Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: PROCESS FOR PREPARING TORREFIED BIOMASS MATERIAL USING A
COMBUSTIBLE LIQUID
TECHNICAL FIELD
The present disclosure pertains to torrefied biomass and/or biosolids, and in
particular, to a torrefied densified biomass and/or torrefied densified
biosolid comprising a
combustible liquid and processes for preparing such torrefied densified
biomass and/or
biosolids using a combustible liquid.
BACKGROUND
Biomass and biosolids are becoming important sources of energy as the supply
of
fossil fuels decreases. Burning of petroleum, coal and other fossil fuels also
leads to
pollutants and greenhouse gases being released into the air and water. Biomass
and biosolids
are renewable, produce significantly fewer greenhouse gases than fossil fuels
and are widely
available. Raw biomass and biosolids, however, generally have a low density
resulting in
inefficient storage and transportation. The low energy densities and higher
moisture contents
of raw biomass and biosolids also hampers the widespread use of raw biomass
and biosolids
as a source of thermal energy or as a coal replacement.
Torrefaction of raw biomass and biosolids has been developed recently to turn
the
biomass and biosolids into a charcoal-like state by slow-heating the biomass
and biosolids in
an oxygen-free or low-oxygen environment to a maximum temperature of about 300
C. The
lack of oxygen prevents the biomass and/or biosolids from burning, and
instead, the material
is torrefied. Slow-heating biomass and biosolids also leads to loss of mass
due to the volatile
organic compounds (VOCs) within the raw biomass and biosolids being gassified.
Torrefaction also causes chemical changes to the cellular structures of the
material, resulting
in a partial loss of mass and a loss in mechanical strength and elasticity.
Torrefaction,
therefore, also produces a product that has increased friability and
grindability. Furthermore,
torrefied material is hydrophobic and therefore, stays dry and is insensitive
to atmospheric
humidity. This reduces the risk of rotting, overheating, and auto-ignition of
the materials
when stored.
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Prior art torrefaction processes generally involve one of high-pressure steam,
high
temperature inert gas or superheated steam in the heat treatment processes.
Other torrefaction
processes using gas or pressure or vacuum methods may also be used. Most of
these prior
technologies, however, fail to efficiently and practically convert biomass
into torrefied wood
in a simple, easy, quick, practical, safe, uniform and economic way. In
particular, using any
type of inert gas or steam involves large containment systems with large
amounts of surface
area, high equipment costs, high energy costs, slow treatment rates, and low
overall operating
efficiencies with resultant high production costs. The systems and equipment
are complex
and large for containing the inert gas or steam heat transfer medium, and
often require
heavyweight materials given the high operating pressures required with steam.
Furthermore,
these systems often require more than an hour to torrefy biomass.
Consequently, the prior
technologies also have challenges with scalability.
Recent torrefaction processes have also used bio-liquids (such as, vegetable
oils,
soybean oils, canola oils or animal tallow), paraffinic hydrocarbons, oil,
molten salts or
paraffin, to heat and torrefy biomass. Some of these technologies, however,
involve
intricately designed housings for holding the liquids and torrefying the
biomass, and require
the biomass to pass through a plurality of pools, rivers or liquid
compartments holding the
liquids during the torrefaction process. These processes, therefore, may
require additional
engineering efforts, complicated designs and large volumes of the torrefying
liquids.
Moreover, these processes often involve a pre-heating stage and/or a drying
stage prior to the
torrefaction treatment, thus, being costly to operate and time-consuming.
SUMMARY
The exemplary embodiments of the present disclosure generally pertain to a
torrefied
densified biomass and/or biosolid comprising a combustible liquid and
processes for
preparing the torrefied densified biomass and/or biosolid using a combustible
liquid
exemplified by hydrocarbons, such as plant-derived oils, marine-derived oils,
animal-derived
oils, petroleum products and bitumen-based products.
An exemplary process for preparing a torrefied densified biomass and/or
torrefied
densified biosolids of the present disclosure is disclosed herein, in which a
combustible liquid
is used for torrefying a densified biomass material and/or densified biosolid
material. The
exemplary process may comprise one of two starting materials: (i) the initial
starting material
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may be raw biomass and/or biosolids that undergo densification prior to
heating in the
combustible liquid; or (ii) the initial starting material may be densified
biomass and/or
densified biosolids that are readily available in the marketplace.
An exemplary process of the present disclosure generally comprises the steps
of
densifying raw biomass and/or biosolids; submerging the densified material
into a
combustible liquid heated to a temperature in a range of about 160 C to about
320 C; and
torrefying the densified material in the heated combustible liquid for about 2
minutes to about
120 minutes to produce a torrefied densified biomass and/or biosolid. The
resulting torrefied
densified material comprises about 2% to about 25% w/w combustible liquid. The
densified
biomass and/or biosolids may be directly transferred from the densifying
process into the
combustible liquid to minimize any loss of heat gained by the
biomass/biosolids
densification. This may increase efficiency of the process as the heated
densified biomass
and/or densified biosolids will require less heating in the combustible
liquid.
The process may further comprise a drying step post-densification or prior to
transferring the densified material into the combustible liquid. Drying may be
done in
conjunction with densification.
The starting feedstock may also comprise commercially available densified
biomass
and/or densified biosolids. With such feedstocks, the initial densification
step disclosed
herein is not required.
The biomass material to be torrefied may comprise any type of material derived
from
living or recently living organisms, and are exemplified by plant biomass such
as sugar-cane
bagasse, corn stover, rice straw, wheat straw, bamboo, switchgrass, and hemp.
The biomass
material may also comprise wood biomass such as softwood, hardwood, sawdust,
hog fuel
and wood byproducts. The biosolids may be recovered from sewage or wastewater
during a
sewage treatment process, alternatively obtained from municipal sewage
treatment processes,
alternatively obtained from industrial waste streams exemplified by fruit and
vegetable
processing plants and fibre processing plants, or alternatively, may be
agricultural wastes
from livestock and poultry production. The biomass and/or biosolids may also
be any
combination of the feedstocks described herein.
The exemplary processes disclosed herein may also be continuous processes,
semi-
continuous processes, or batch processes. In such processes, the supply of
biomass material to
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a pelleter or briquetter may be continuous or semi-continuous or in batches.
Alternatively, if
commercially available densified biomass and/or densified biosolids are used,
then the supply
of such densified material to the combustible liquid may be continuous or semi-
continuous or
in batches.
The combustible liquid preferably comprises a hydrocarbon exemplified by plant-
derived oils, marine-derived oils, animal-derived oils, petroleum products and
bitumen-based
products that are heatable to a temperature of up to about 320 C. The
combustible liquid may
be derived from any source such as, for example, an oil derived from a plant
source, a marine
source, an animal source, a petroleum product and a bitumen-based product. For
example, the
combustible liquid may be canola oil, linseed oil, sunflower oil, safflower
oil, corn oil, peanut
oil, palm oil, soybean oil, rapeseed oil, cottonseed oil, palm kernel oil,
coconut oil, sesame
seed oil, olive oil, animal tallow, fish oil, liver oil, and mixtures thereof
Alternatively, the
combustible liquid may be a petroleum-based oil or a bitumen-based oil, such
as, for
example, a synthetic motor oil or engine oil exemplified by 5W-30 and 10W-30
engine oil; a
chainsaw bar oil; a chain oil; transmission fluid oils and fluids exemplified
by automatic
transmission fluids (ATF); hydraulic fluids; gear oils; diesel fuel; paraffin
wax; paraffin oil;
kerosene, stove oil; and mixtures thereof
The torrefied densified biomass and/or biosolid disclosed herein and obtained
from
the processes described herein may absorb between about 2% and 25% w/w
combustible
liquid during the torrefaction process, and may have a heat energy value of
about 6,000 BTU
per pound on a bone dry basis to about 13,000 BTU per pound on a bone dry
basis, or any
amount therebetween. The heat energy value may also be expressed in gigajoules
per metric
tonne (GJ/t), with the torrefied densified biomass and/or biosolid obtained
from the processes
described herein having a heat energy value of about 22 GJ/t on a bone dry
basis to about 27
GJ/t on a bone dry basis, or any amount therebetween.
The torrefied densified biomass and/or biosolid disclosed herein and obtained
from
the processes described herein may also comprise a carbon content of about 50
carbon % on a
bone dry basis to about 65 carbon % on a bone dry basis and may also be
hydrophobic in
nature.
The exemplary processes disclosed herein may also include a gas collection and
condenser system for collecting and separating VOCs, vapours and steam
expelled and/or
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generated during the densification, drying and torrefaction processes, for
condensation and
separation into reusable energy sources.
The claimed invention relates to a continuous process for preparing a
torrefied densified
biomass comprising the steps of: (a) providing a supply of densified biomass
material or
5 densifying a supply of a biomass feedstock to obtain a densified biomass
material; (b) submerging
the densified biomass material in a combustible liquid; (c) torrefying the
densified biomass material
in the combustible liquid at a temperature or a range of temperatures of about
270 C to about
320 C for a period of time that is at least 10 minutes to about 120 minutes,
to produce the toadied
densified biomass; (d) conveying the torrefied densified biomass from the
combustible fluid into a
water bath; and (e) recovering cooled torrefied densified biomass from the
water bath; wherein the
torrefied densified biomass recovered at step (e) comprises no more than about
20% w/w water
after 5 minutes of drip drying and comprises about 2% to about 20% w/w of the
combustible liquid.
Also claimed is a continuous process for producing torrefied pellets
comprising the steps of: (a)
densifying a supply of a biomass feedstock and extruding therefrom densified
pellets; (b)
conveying the densified pellets into and through an input end of a torrefusion
reactor to submerge
the densified pellets in a combustible liquid contained within the torrefusion
reactor, the
combustible liquid having a temperature of about 270 C to about 320 C; (c)
conveying the
submerged densified pellets from the input end to an output end of the
torrefusion reactor for a
period of time that is at least 10 minutes to about 120 minutes, wherein the
densified pellets are
torrefied; (d) discharging the torrefied pellets from the output end of the
torrefusion reactor and
conveying the torrefied pellets into and through a cooler; and (e) recovering
cooled torrefied
pellets from the cooler, the cooled torrefied pellets comprising about 2% to
about 20% w/w of the
combustible liquid; wherein the cooler of step (d) is a water bath and wherein
washing of the
torrefied pellets by water in the water bath removes residual combustible
liquid from outer surfaces
of the torrefied pellets and wherein the cooled torrefied densified pellets
recovered at step (e) have
a water content of no more than about 20% w/w after 5 minutes of drip drying.
In such a process,
thermal energy may be recovered from the water bath. The process may further
comprise the steps
of: (i) combining in a torgas heater, gases produced during step (c) and
combusting therein to
produced heated air; and (ii) using the heated air to heat the combustible
liquid. One or both of the
period of time in step (c) and the temperature or range of temperatures in
step (c) may be selected
whereby the product of step (e) has a water content of about 1% to about 12%
(w/w) or about 2% to
about 10% (w/w), after five minutes of drip drying.
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DESCRIPTION OF THE DRAWINGS
The present disclosure will be described in conjunction with reference to the
following
drawings in which:
Fig. 1 is a schematic flowchart showing an exemplary process for preparing a
torrefied
densified biomass material and/or a torrefied densified biosolid material;
Fig. 2 is schematic flowchart showing a second exemplary process for preparing
a
toadied densified biomass material and/or a torrefied densified biosolid
material;
Fig. 3 is a schematic flowchart showing an exemplary process for densification
and
torrefaction of a biomass feedstock;
Fig. 4 is a schematic flowchart showing an exemplary process for densification
and
torrefaction of a hog fuel feedstock;
Fig. 5(A) is a perspective top-side view of an exemplary embodiment of a
torrefusion
reactor for use in a continuous, semi-continuous or batch throughput
torrefaction process of the
present disclosure, showing torrefied pellets being transported out of a
combustible liquid; Fig.
5(B) is a perspective top-side view of an exemplary alternative embodiment of
a torrefusion
reactor for use in a continuous, semi-continuous or batch throughput
torrefaction process of the
present disclosure, with densified biomass and/or densified biosolids being
loaded in a
densified biomass/biosolids metering bin;
Fig. 6(A) is a perspective top-side view of the torrefusion reactor shown in
Fig. 5(B),
showing torrefied pellets being transported out of a combustible liquid; and
Fig. 6(B) is a
perspective top-side view of the torrefusion reactor shown in Fig. 5(B),
showing the direction
of rotation of the conveyor of the torrefusion reactor as densified biomass
and/or densified
biosolids proceed through the continuous, semi-continuous or batch throughput
torrefaction
process of the present disclosure;
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Fig. 7 is a chart showing physicochemical changes that occur in a biomass
feedstock
over a period of time during processing with an exemplary torrefaction process
disclosed
herein;
Fig. 8 is a graph showing the heat value of biomass feedstock that has been
processed
with an exemplary torrefaction process disclosed herein, wherein the biomass
feedstock has
been processed at different temperatures for different periods of time;
Fig. 9 is a graph showing the heat value of biomass feedstock that has been
processed
with an exemplary torrefaction process disclosed herein, wherein the biomass
feedstock has
been processed at different temperatures for different periods of time;
Fig. 10 is a graph showing the carbon content of a biomass feedstock that has
been
processed with an exemplary torrefaction process disclosed herein, wherein the
biomass
feedstock has been processed at different temperatures for different periods
of time;
Fig. 11 is a graph showing the mass of biomass feedstock and the oil
absorption by
biomass feedstock that has been processed for different time periods using
canola oil as the
combustible liquid;
Fig. 12 is a graph showing the mass of biomass feedstock and the oil
absorption by
biomass feedstock that has been processed for different time periods using
paraffin wax as
the combustible liquid;
Fig. 13 is a graph showing a comparison between the total losses of
combustible
liquids canola oil and paraffin wax in an exemplary torrefaction process
according to the
present disclosure;
Fig. 14 is a graph showing a comparison between the reductions in weight of
biomass
feedstock (in %) when canola oil or paraffin wax are used as the combustible
liquids in an
exemplary torrefaction process according to the present disclosure;
Fig. 15 is a graph showing comparisons of water absorption by biomass
feedstocks
that have been processed at different temperatures for different periods of
time in an
exemplary torrefaction process according to the present disclosure;
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Fig. 16 is a graph showing comparisons of water absorption by biomass
feedstocks
that have been processed for increasing time periods and at increasing time
periods with an
exemplary torrefaction process of the present disclosure;
Fig. 17 is a graph showing total oil absorptions by biomass feedstock
processed with
different types of oil as combustible liquids with an exemplary torrefaction
process of the
present disclosure;
Fig. 18 is a graph showing total oil absorptions by biomass feedstock
processed with
different types of oil as combustible liquids with an exemplary torrefaction
process of the
present disclosure; and
Fig. 19 is a perspective side view of a small-scale torrefusion reactor
suitable for use
in some of the exemplary torrefaction processes disclosed herein.
DETAILED DESCRIPTION
The exemplary embodiments of the present disclosure pertain to torrefied
densified
biomass and/or torrefied densified biosolids comprising a combustible liquid
exemplified by
hydrocarbons. Some exemplary embodiments pertain to processes for preparing a
torrefied
densified biomass and/or torrefied densified biosolids comprising a
combustible liquid.
Suitable combustible liquids are exemplified by plant-derived oils, marine-
derived oils,
animal-derived oils, petroleum-based products and bitumen-based products.
The exemplary torrefaction processes disclosed herein require a reduced energy
consumption as compared to prior art processes, while improving process
efficiency and
feedstock throughput. Energy exemplified by VOCs and steam, produced during
the process,
may be recycled through the system to heat the combustible liquid, and/or to
create pellets for
torrefaction, and/or to torrefy the densified biomass. It was surprisingly
found that minimal
oil is actually absorbed by the densified biomass during the present
torrefaction processes.
Accordingly, the combustible liquids used during the torrefaction steps may be
repeatedly
recycled and reused to process additional biomass feedstocks, thus reducing
input costs.
Furthermore, any type of oil may be used for these processes, including less
valuable and
cheaper oils that may have high contents of unsaturated fats, thereby even
further reducing
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input costs. It is to be noted that use of a densified material as a biomass
feedstock will
reduce torrefaction processing time, as demonstrated in the Examples provided
herein.
The torrefaction processes disclosed herein also do not require a vast amount
of space
to operate and are easily assembled and used, especially given that the
various steps of the
process do not need to occur within a wholly connected system. The dryer,
densifier,
receiving container for torrefaction, and cooling system may all be stored
separately and set
up in independent locations.
Moreover, the torrefaction processes disclosed herein provide an improved
quality of
torrefied densified biomass as the residual oil on the surface of the
torrefied densified
biomass reduces the amount of dust and other combustible materials on the
biomass' surface.
The torrefied densified biomass produced by the exemplary processes is
therefore
hydrophobic. Accordingly, the exemplary processes produce a torrefied
densified product
that is easily transportable and shippable as it does not create an explosion
hazard. The
torrefied densified product can readily be used as a biofuel.
Suitable biomass feedstocks for exemplary processes and products disclosed
herein
include harvested plant materials exemplified by hardwood trees and softwood
trees which
may have been processed into chips and/or sawdust and/or pellets, including
briquettes,
and/or debris and wood waste from wood-processing operations, fibrous annual
or perennial
crops such as Salix, switchgrass, corn stover, straws produced from harvesting
of cereals
and/or oilseed crops; or material obtained from waste streams produced from
fruit processing
plants or vegetable processing plants or cereals processing plants or oilseeds
processing
plants, or obtained from bagasse from sugar cane. Also suitable are biosolids
materials. As
used herein, "biosolids" means any solid or semisolid organic material
recovered from
sewage or wastewater during a sewage treatment process, obtained from
municipal sewage
treatment processes, or alternatively, may be agricultural wastes from
livestock and poultry
production.
The use of biomass materials has been limited as biomass generally has a lower
energy content and lower energy density compared to traditional fossil fuels.
The present
disclosure pertains to a densified or pelletized biomass material, including
biomass densified
into briquettes, as the starting material for torrefaction to increase the
starting energy of the
raw biomass material (for example, pelletized or otherwise densified biomass,
such as
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briquettes, on a dry basis, can have an energy value of up to 40 lbs/cu ft, as
compared to 8
lbs/cu ft for loose biomass material). As understood in the art, densification
is a process for
increasing the density of the biomass, and many forms of densified biomass are
readily
available, such as wood pellets and briquettes. Moreover, various procedures
for densifying
biomass are known in the art and may be employed in the present process, such
as, but not
limited to, extrusion, briquetting, pelleting and agglomeration.
The term "densified" as used herein means a biomass material that has been
compressed to increase its density. The densified biomass material will be
understood to be
various shaped modules of biomass, with the individual pieces having uniform
shapes or non-
non-uniform shapes.
The term "pelletized" as used herein means a biomass material that has been
compacted or concentrated into pellets, or pressed into briquettes. The
pellets may be of any
shape such as those exemplified by cubes, pellets, pucks, briquettes, and
synthetic logs,
wherein the individual pieces have uniform shapes or non-non-uniform shapes.
The
briquettes may also be of any shape such as exemplified by squares,
rectangules, triangules,
quadrilaterals, or any regular polygon (such as, for example, pentagons,
heptagons, octagons
and the like) or alternatively irregular polygons. The individual pieces may
have uniform
shapes or non-uniform shapes, asymmetric shapes or symmetric shapes.
Hereinafter, the term "densified" shall refer to densified and pelletized
materials
collectively, including, without limitation, pellets and briquettes, which
retain some moisture
content, such as, for example, an initial moisture content in the densified
biomass and/or
biosolids material of at least about 1%. The densified biomass and/or
biosolids material may
also have an initial moisture content of at least about 1.5%, at least about
2%, at least about
2.5%, at least about 3%, at least about 3.5%, at least about 4%, at least
about 4.5%, at least
about 5%, at least about 5.5%, at least about 6%, at least about 6.5%, at
least about 7%, at
least about 7.5%, at least about 8%, at least about 8.5%, at least about 9%,
at least about
9.5%, at least about 10%, at least about 11%, at least about 12%, at least
about 13%, at least
about 14%, at least about 15%, at least about 16%, at least about 17%, at
least about 18%, at
least about 19%, at least about 20%, or any moisture content therebetween.
The term "densification" used herein shall refer to densification,
pelletization and
briquetting processes. Furthermore, the densified biomass material may also be
referred to as
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"pellets," "cubes" or "briquettes" herein. However, it should be understood
that the densified
biomass referred to herein does not include charcoal briquettes which are
already torrefied
and therefore cannot be torrefied any further.
As used herein, the term "wet basis" or "As Received Basis" refers to actual
values or
5 chemical measurements of a sample of densified biomass material or a
sample of torrefied
densified biomass, as obtained from an analysis of the sample, and includes,
without
limitation, moisture content, % ash, % volatile matter, % fixed carbon, %
sulphur, % carbon,
% nitrogen, % oxygen, and calorific values, such as heat energy values in
Btu/lb, GJ/t,
Kcal/kg.
10 As used
herein, the term "dry basis" refers to theoretical values that are calculated
from the "wet basis" or "as received basis" values to provide results for a
sample of densified
biomass material or a sample of torrefied densified biomass as if there was no
moisture in the
sample (i.e., if it was bone dry; total heat value as though dry).
Accordingly, as used herein,
the term "bone dry basis" refers to the theoretical value for a sample of
densified biomass
material or a sample of torrefied densified biomass with zero detectable
moisture content.
The torrefaction processes of the present disclosure generally pertain to
immersion of
densified biomass material into a combustible liquid maintained at a
temperature in the range
of about 160 C to about 320C, for a period of time in the range of about 2
minutes to about
120 minutes, for about 5 minutes to about 120 minutes, for about 8 minutes to
about 90
minutes, for about 10 minutes to about 60 minutes, for about 12 minutes to
about 45 minutes,
or for about 15 minutes to about 30 minutes.
As used herein, the term "combustible liquid" means the liquid for contacting
and
immersing therein the densified biomass material, and then torrefying the
densified biomass
material in the combustible liquid. The term "combustible liquid" may comprise
a
hydrocarbon-based oil exemplified by plant-derived oils, marine-derived oils,
animal-derived
oils, petroleum products and bitumen-based products, and may also comprise a
synthetic fuel
or a synthetic oil. Suitable plant-derived oils are exemplified by canola oil,
linseed oil,
sunflower oil, safflower oil, corn oil, peanut oil, palm oil, soybean oil,
rapeseed oil,
cottonseed oil, palm kernel oil, coconut oil, sesame seed oil, olive oil, and
mixtures of plant-
derived oils. Suitable animal-derived oils are exemplified by animal tallow,
fryer greases, and
liver oil among others, and mixtures thereof Suitable marine-derived oils are
exemplified by
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whale oil, seal oil, fish oil, algal oils, and mixtures of marine-derived
oils. Suitable petroleum
products are exemplified by synthetic motor oil and engine oils such as
exemplified by 5W-
30 and 10W-30 engine oils, chainsaw bar oil, chain oil, transmission fluid
oils and fluids such
as automatic transmission fluids (ATF), hydraulic fluids, gear oils, diesel
fuel, paraffin wax,
paraffin oil, kerosene, and stove oil, among others, and mixtures thereof A
suitable synthetic
fuel or synthetic oil may be produced by a Fischer Tropsch conversion process
and is
exemplified by pyrolysis oil and the like. The combustible liquid may also be
any
combinations of plant-derived oils, marine-derived oils, animal-derived oils,
petroleum
products and synthetic fuels or oils. The combustible liquid used in the
present disclosure
may further be heatable to a temperature of up to 320 C. As used herein, the
combustible
liquid is for heating densified biomass material in an oxygen-free environment
to torrefy the
densified material without igniting it, rather than for the infusion of
densified biomass
material with the combustible liquid or alternatively, for causing a
significant increase in
absorption of combustible liquid by densified biomass material.
The products of the torrefaction processes disclosed herein are
torrefied/densified
biomass and/or biosolids material that retain a portion of the combustible
liquid and have a
high degree of hydrophobicity. The torrefied densified biomass and/or biosolid
obtained from
the processes described herein may absorb between about 2% and about 25% w/w
combustible liquid during the torrefaction process, or any amount
therebetween. For example,
without limitation, the amount of combustible liquid absorbed and retained
within torrefied
densified biomass may be about 2% to about 25% w/w combustible liquid, or any
amount
therebetween; about 2% to about 24% w/w combustible liquid, or any amount
therebetween;
about 2% to about 23% w/w combustible liquid, or any amount therebetween;
about 2% to
about 22% w/w combustible liquid, or any amount therebetween; about 2% to
about 21%
w/w combustible liquid, or any amount therebetween; about 2% to about 20% w/w
combustible liquid, or any amount therebetween; about 2% to about 19% w/w
combustible
liquid, or any amount therebetween; about 2% to about 18% w/w combustible
liquid, or any
amount therebetween; about 2% to about 17% w/w combustible liquid, or any
amount
therebetween; such as, for example, 3% w/w combustible liquid, 4% w/w
combustible liquid,
5% w/w combustible liquid, 6% w/w combustible liquid, 7% w/w combustible
liquid, 8%
w/w combustible liquid, 9% w/w combustible liquid, 10% w/w combustible liquid,
11% w/w
combustible liquid, 12% w/w combustible liquid, 13% w/w combustible liquid,
14% w/w
combustible liquid, 15% w/w combustible liquid, 16% w/w combustible liquid, or
any
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12
amount therebetween.
Those skilled in the art would understand that the biomass and/or biosolid
materials of
the present disclosure have a range of heat energy values. Those skilled in
the art would
know that exemplary energy values of the densified biomass and/or biosolids
may range from
about 4,300 BTU per pound to about 12,800 BTU per pound, depending on the
feedstock and
the moisture content of the feedstock. For example, a skilled person in the
art would known
that wood generally has an energy content of about 6,400 BTU per pound with
20% moisture
(air dry basis) to about 7,600 to about 9,600 BTU per pound on a bone dry
basis (or about 15
GJ/t with 20% moisture to about 18-22 GJ/t on a bone dry basis), and that
agricultural
residues, such as switchgrass, have an energy content of about 4,300 BTU per
pound to about
7,300 BTU per pound (or about 10-17 GJ/t), depending on the moisture content
of the
agricultural residue. In addition, those skilled in the art would known that
charcoal has an
energy content of about 12,800 BTU per pound. Accordingly, a skilled person
would
appreciate that the range of heat energy values following torrefaction can
also vary, with
those biomass and/or biosolid material having a lower initial heat energy
value producing an
end product having a lower heat energy value compared to a biomass and/or
biosolid material
having a higher initial heat energy value. In addition, as described herein,
different factors
can be varied, such as, without limitation, the density of the densified
biomass, the
temperature of the combustible liquid, the submersion time of the densified
biomass in the
combustible liquid, and the type of combustible liquid used, to obtain a
particular heat energy
value for a torrefied densified biomass and/or biosolid material of the
present disclosure.
The torrefied densified biomass and/or biosolid of the present disclosure may
accordingly have a heat energy value of about 6,000 BTU per pound on a bone
dry basis to
about 13,000 BTU per pound on a bone dry basis, or any heat energy value
therebetween, for
example, from about 6,000 BTU per pound on a bone dry basis to about 12,000
BTU per
pound on a bone dry basis, or any heat energy value therebetween; from about
6,000 BTU per
pound on a bone dry basis to about 11,000 BTU per pound on a bone dry basis,
or any heat
energy value therebetween; from about 6,000 BTU per pound on a bone dry basis
to about
10,000 BTU per pound on a bone dry basis, or any heat energy value
therebetween; from
about 6,000 BTU per pound on a bone dry basis to about 9,000 BTU per pound on
a bone dry
basis, or any heat energy value therebetween; from about 9,000 BTU per pound
on a bone dry
basis to about 13,000 BTU per pound on a bone dry basis, or any heat energy
value
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13
therebetween, such as, for example, about 9,500 BTU per pound on a bone dry
basis; about
10,000 BTU per pound on a bone dry basis; about 10,500 BTU per pound on a bone
dry
basis; about 11,000 BTU per pound on a bone dry basis; about 11,500 BTU per
pound on a
bone dry basis; about 12,000 BTU per pound on a bone dry basis; about 12,500
BTU per
pound on a bone dry basis on a bone dry basis; about 13,000 BTU per pound, or
any heat
energy value therebetween. The heat energy value may also be expressed in
terms of
gigajoules per metric tonne (GJ/t). The torrefied densified biomass and/or
biosolid may
therefore comprise a heat energy value of about 22 GJ/t on a bone dry basis to
about 27 GJ/t
on a bone dry basis, or any heat energy value therebetween, for example, from
about 22 GJ/t
on a bone dry basis to about 26.5 GJ/t on a bone dry basis or any heat energy
value
therebetween; from about 22 GJ/tt on a bone dry basis to about 26 GJ/t on a
bone dry basis or
any heat energy value therebetween; from about 22 GJ/t on a bone dry basis to
about 26 GJ/t
on a bone dry basis or any heat energy value therebetween; from about 22 GJ/t
on a bone dry
basis to about 25 GJ/t on a bone dry basis or any heat energy value
therebetween; from about
22 GJ/t on a bone dry basis to about 24 GJ/t on a bone dry basis or any heat
energy value
therebetween; or from about 22 GJ/t on a bone dry basis to about 23 GJ/t on a
bone dry basis
or any heat energy value therebetween.
Furthermore, the torrefied densified biomass disclosed herein may have a
carbon
content of about 50 carbon % on a bone dry basis to about 65 carbon % on a
bone dry basis,
or any amount therebetween. For example, without limitation, the carbon
content of the
torrefied densified biomass may be about 51 carbon % on a bone dry basis, 52
carbon % on a
bone dry basis, 53 carbon % on a bone dry basis, 54 carbon % on a bone dry
basis, 55 carbon
% on a bone dry basis, 56 carbon % on a bone dry basis, 57 carbon % on a bone
dry basis, 58
carbon % on a bone dry basis, 59 carbon % on a bone dry basis, 60 carbon % on
a bone dry
basis, 61 carbon % on a bone dry basis, 62 carbon % on a bone dry basis, 63
carbon % on a
bone dry basis, 64 carbon % on a bone dry basis, 65 carbon % on a bone dry
basis, or any
amount therebetween.
The torrefied end products are easily grindable into particulate and/or
powdered forms
that are particularly suitable for use as fuels for generation of power and/or
heat.
Furthermore, the torrefied material is easily transported and stored and are
hydrophobic in
nature.
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A schematic flowchart is shown in Fig. 1 that illustrates an exemplary process
of the
present disclosure for preparing a torrefied densified biomass and/or biosolid
material having
a higher energy density value as compared to a non-torrefied biomass material.
In this
embodiment, the starting raw biomass material 2 is not densified and the
process for
preparing the torrefied densified biomass material includes initial steps of
drying and
densifying raw biomass material 2 into densified biomass material 20. For the
torrefaction
process, a receiving container 10 is filled with a combustible liquid 12, as
described above.
Combustible liquid 12 is heated up to a temperature in a range of about 160 C
to about
320 C, and densified biomass material 20 is immersed in the hot combustible
liquid 12 in
to receiving container 10. Densified biomass material 20 is completely
submerged in the hot
combustible liquid 12 to create an "oxygen-free" environment. The hot
combustible liquid 12
may be maintained at a temperature in a range of about 160 C to about 320 C,
or any
temperature therebetween. Alternatively, the temperature of the hot
combustible liquid 12
may be varied during the process between about 160 C and about 320 C. Whether
combustible liquid 12 is maintained at a certain temperature or varied during
the process, the
temperature of densified biomass 20 is increased from its initial temperature
to a temperature
in a range of about 160 C to about 320 C, or any temperature therebetween.
During this
heating process, most of the moisture is driven out of densified biomass 20
and densified
biomass 20 takes in heat energy in an endothermic reaction. Densified biomass
20 also
undergoes chemical and structural changes and expels some VOCs contained
within
densified biomass 20. The resulting torrefied densified biomass 30 is removed
from receiving
container 10 and cooled in a cooling system 32.
Any type of densification process described in the art may be used in the
present
process to produce a densified biomass material 20 for torrefaction. For
example, densifier 5
may be a pelletizer, as known in the art, and may comprise an extrusion
process for
producing pellets (including, for example, a pellet mill extruder, a screw
extruder), a hammer
mill, a piston press, a wheel press or a briquetter for pressing biomass into
a briquette, or may
involve agglomeration. Densification may also include the addition of pellet
binders during
the densification process to ensure that pellet quality is maintained. The
densification process
may also involve pre-heating and melting of the raw biomass material 2 through
mechanical
action and friction and heat, resulting in a significant reduction of volume,
elimination of
some moisture and air, and an increase in temperature of the biomass. After
raw biomass
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material 2 is densified, the resulting densified biomass 20 proceeds through
the torrefaction
process.
The present disclosure also provides that a dryer 7 may be used to reduce the
moisture
content in raw biomass material 2 before and/or after densification and before
torrefaction.
5 Those skilled in the art will appreciate that any dryer known in the art
may be used, such as,
for example, the AltentechTM BiovertidryerTM (available from AltentechTM Power
Inc.,
Vancouver, BC, Canada), together with densifier 5. The drying process may be
useful in
further heating of the densified biomass material 20 prior to torrefaction,
thereby increasing
the efficiency of the torrefaction process.
10 Dryer 7
and/or densifier 5 (or a combined dryer/densifier) may be located near
receiving container 10 containing combustible liquid 12. With such an
arrangement, densified
biomass 20 may be directly transferred from densifier 5 and/or dryer 7 (or a
combined
dryer/densifier) to receiving container 10 without cooling the densified
biomass 20 in-
between. Those skilled in the art will appreciate that through the action of
densifiers and
15 melding raw material into a compact product, densifiers produce
significant heat, thus
resulting in a heated densified product. Dryers known in the art also use
significant heat to
extract moisture from raw biomass, thus further increasing the heat of a
densified product.
Accordingly, densified biomass 20 is at a temperature greater than ambient
temperature
immediately following densification and/or drying. Transfer of densified
biomass 20 directly
from densifier 5 and/or dryer 7 (or a combined dryer/densifier) to receiving
container 10 may
assist in further reducing the costs of torrefying biomass and increase the
efficiency of the
process as the initial temperature of densified biomass 20 entering
combustible liquid 12 is
higher than ambient temperature. Alternatively, the densified biomass 20 may
be cooled
before transferring from densifier 5 and/or dryer 7 (or a combined
dryer/densifier) to
receiving container 10.
Importantly, the present disclosure provides for densification prior to
contact with any
type of oil; that is, raw biomass material 2 is densified prior to contacting
any oil of the
combustible liquid (or densified biomass 20 is used as the starting material).
Those skilled in
the art will appreciate that fat and oil may interfere with steam absorption
and reduce
pelletability. Fats and oils may be used during pelleting, but generally to
lubricate the die and
ensure a smooth start-up after the die cools off Oil is mixed with raw
biomaterial following
densification to purge the die prior to shutdown and is not for actual
pelletization of the
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biomass. In fact, oil-saturated biomass from a pellet press may be saved
following
pelletization for reuse in a subsequent shutdown sequence (see, for example,
Kofman, PD.
"The production of wood pellets." Coford Connects, Processing/Products No. 10,
pages 1-6,
2012). Accordingly, the present disclosure provides an improved torrefied
densified biomass
as compared to prior art processes which coat biomass with oil prior to
densification.
Receiving container 10 may be any type of container that can be heated to a
temperature of up to about 320 C and can hold hot combustible liquid at a
temperature of up
to about 320 C for extended periods of time. It is, therefore, understood that
receiving
container 10 be of a simple design. For example, receiving container 10 may be
a
commercially available deep fryer exemplified by a PITCO fryer (PITCO is a
registered
trademark of Pitco Frialator, Inc., Burlington, Vermont, U.S.A.), a VULCAN
fryer
(VULCAN is a registered trademark of Vulcan-Hart Corporation, Chicago,
Illinois, U.S.A.),
a FRYMASTER (FRYMASTER is a registered trademark of Frymaster LLC,
Shreveport,
Louisiana, U.S.A.), a Southbend fryer, or a DEAN fryer (DEAN is a registered
trademark of
Frymaster LLC, Shreveport, Louisiana, U.S.A.); or, receiving container 10 may
be any sized
drum, tank, pot or other container that can be heated directly from below to a
temperature of
about 320 C, and that can hold a combustible liquid at a temperature of about
320 C for
extended periods of time. Receiving container 10 is also sufficiently sized to
receive the
desired amount of densified biomass 20 together with the combustible liquid
12.
Combustible liquid 12 may be heated using a heat source directly below
receiving
container 10 or using an external heat source to heat the combustible liquid
12, which can be
transferred into receiving container 10 once it reaches its operating
temperature. The external
heat source may be, for example, a nuclear reactor with modest thermal output,
a furnace that
burns coal or natural gas, or a portion of the produced biocoal, with or
without additional heat
exchangers.
It is understood that, to minimize costs of the exemplary processes described
herein,
the size of receiving container 10 and the amount of combustible liquid 12
used may be
limited to a size and amount that is sufficient to completely submerge the
particular quantity
of densified biomass 20 to be torrefied. Moreover, smaller amounts of
combustible liquid
may also be used if densified biomass 20 comprises smaller-sized pellets or
briquettes.
Accordingly, the exemplary processes described herein may be varied in order
to make the
process more efficient and less costly, and can be adjusted according to a
user's needs.
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As described above, combustible liquid 12 may be heated to a temperature in a
range
of about 160 C to about 320 C, or any temperature therebetween, and the
combustible liquid
12 may be maintained at this temperature during the torrefaction process. By
way of further
example, the temperature that combustible liquid 12 may be heated to and
maintained at can
vary in a range of between about 180 C to about 320 C, or any temperature
therebetween;
between about 180 C to about 300 C, or any temperature therebetween; between
about 200 C
to about 320 C, or any temperature therebetween; between about 200 C and about
310 C, or
any temperature therebetween; between about 200 C and about 300 C, or any
temperature
therebetween; between about 200 C and about 290 C, or any temperature
therebetween;
between about 200 C and about 280 C, or any temperature therebetween; between
about
200 C and about 270 C, or any temperature therebetween; between about 200 C
and about
260 C, or any temperature therebetween; between about 200 C and about 250 C,
or any
temperature therebetween; between about 200 C and about 240 C, or any
temperature
therebetween; between about 220 C and about 300 C, or any temperature
therebetween;
between about 220 C and about 290 C, or any temperature therebetween; between
about
220 C and about 280 C, or any temperature therebetween; between about 220 C
and about
270 C, or any temperature therebetween; between about 220 C and about 260 C,
or any
temperature therebetween; between about 220 C and about 250 C, or any
temperature
therebetween; between about 220 C and about 240 C, or any temperature
therebetween; or
can be about 162 C, 165 C, 168 C, 170 C, 172 C, 175 C, 178 C, 180 C, 181 C ,
182 C ,
183 C , 184 C , 185 C , 186 C , 187 C , 188 C , 189 C , 190 C , 191 C, 192 C,
193 C,
194 C, 195 C, 196 C, 197 C, 198 C, 199 C, 200 C, 201 C, 202 C, 203 C, 204 C,
205 C,
206 C, 207 C, 208 C, 209 C, 210 C, 211 C, 212 C, 213 C, 214 C, 215 C, 216 C,
217 C,
218 C, 219 C, 220 C, 22FC, 222 C, 223 C, 224 C, 225 C, 226 C, 227 C, 228 C,
229 C,
230 C, 23FC, 232 C, 233 C, 234 C, 235 C, 236 C, 237 C, 238 C, 239 C, 240 C,
24FC,
242 C, 243 C, 244 C, 245 C, 248 C, 250 C, 252 C, 255 C, 258 C, 260 C, 262 C,
264 C,
266 C, 268 C, 270 C, 272 C, 274 C, 276 C, 278 C, 280 C, 282 C, 284 C, 286 C,
288 C,
290 C, 292 C, 294 C, 296 C, 298 C, 300 C, 302 C, 304 C, 306 C, 308 C, 310 C,
312 C,
314 C, 316 C, 318 C, 320 C, or any temperature therebetween.
It is further contemplated that the temperature of combustible liquid 12 may
be heated
in a step-wise fashion. This step-wise heating may be done in a single
receiving container 10
such that the same combustible liquid is heated to an initial temperature and
then heated to an
increased temperature for torrefying densified biomass 20. Using a single
receiving container
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18
reduces any costs that would be associated with transferring densified biomass
20
between multiple receiving containers 10, using multiple volumes of
combustible liquid 12,
and heating multiple volumes of combustible liquid 12.
Combustible liquid 12 may be heated to an initial lower temperature prior to
loading
5 with densified biomass 20. Once densified biomass 20 is submerged within
combustible
liquid 12 at the lower initial temperature for a certain period of time,
combustible liquid 12
may be heated to a higher temperature for torrefaction. Such a step-wise
heating of
combustible liquid 12 and densified biomass 20 may result in a more efficient
and less costly
process, as the initial lower temperature may be used for heating densified
biomass 20 from
10 its starting temperature to a higher temperature and for releasing the
majority of the moisture
from densified biomass 20; the higher temperature, on the other hand, may be
used for a
shorter period of time for torrefying densified biomass 20. Accordingly, less
energy may be
required as a higher temperature would be required for a shorter period of
time. By way of
example, combustible liquid 12 may be initially heated to a temperature in a
range of about
HOT to about 200 C, or any temperature therebetween, such as, but not limited
to, about
110 C, 112 C, 114 C, 116 C, 118 C, 120 C, 122 C, 124 C, 126 C, 128 C, 130 C,
132 C,
134 C, 136 C, 138 C, 140 C, 142 C, 144 C, 148 C, 150 C, 151 C, 152 C, 153 C,
154 C,
155 C, 156 C, 157 C, 158 C, 159 C, 160 C, 161 C, 162 C, 163 C, 164 C, 165 C,
166 C,
167 C, 168 C, 169 C, 170 C, 171 C, 172 C, 173 C, 174 C, 175 C, 176 C, 177 C,
178 C,
179 C, 180 C, 182 C, 185 C, 188 C, 190 C, 192 C, 195 C, 198 C, 200 C, or any
temperature
therebetween. Densified biomass 20 may be submerged within the lower
temperature for
about 2 minutes to about 30 minutes, or any amount of time therebetween, such
as 2.5, 3, 3.5,
4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5,
13, 13.5, 14, 14.5, 15,
15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 20.5, 21, 21.5, 22, 22.5,
23, 23.5, 24, 24.5, 25,
25.5, 26, 26.5, 27, 27.5, 28, 28.5, 29, 29.5, 30 minutes, or any amount of
time therebetween.
Following the initial period of the heat treatment, combustible liquid 12,
containing densified
biomass 20 submerged therein, may be further heated to a temperature of about
180 C to
about 320 C, or any temperature therebetween, such as, but not limited to,
about 181 C ,
182 C , 183 C , 184 C , 185 C , 186 C , 187 C , 188 C , 189 C , 190 C , 191 C,
192 C,
193 C, 194 C, 195 C, 196 C, 197 C, 198 C, 199 C, 200 C, 201 C, 202 C, 203 C,
204 C,
205 C, 206 C, 207 C, 208 C, 209 C, 210 C, 211 C, 212 C, 213 C, 214 C, 215 C,
216 C,
217 C, 218 C, 219 C, 220 C, 22FC, 222 C, 223 C, 224 C, 225 C, 226 C, 227 C,
228 C,
229 C, 230 C, 23FC, 232 C, 233 C, 234 C, 235 C, 236 C, 237 C, 238 C, 239 C,
240 C,
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24FC, 242 C, 243 C, 244 C, 245 C, 248 C, 250 C, 252 C, 255 C, 258 C, 260 C,
262 C,
264 C, 266 C, 268 C, 270 C, 272 C, 274 C, 276 C, 278 C, 280 C, 282 C, 284 C,
286 C,
288 C, 290 C, 292 C, 294 C, 296 C, 298 C, 300 C, 302 C, 304 C, 306 C, 308 C,
310 C,
312 C, 314 C, 316 C, 318 C, 320 C, or any temperature therebetween. Densified
biomass 20
may be torrefied in the higher temperature for about 2 minutes to about 60
minutes, or any
amount of time therebetween, such as 2.5 minutes, 3 minutes, 3.5 minutes, 4
minutes, 4.5
minutes, 5 minutes, 5.5 minutes, 6 minutes, 6.5 minutes, 7 minutes, 7.5
minutes, 8 minutes,
8.5 minutes, 9 minutes, 9.5 minutes, 10 minutes, 10.5 minutes, 11 minutes,
11.5 minutes, 12
minutes, 12.5 minutes, 13 minutes, 13.5 minutes, 14 minutes, 14.5 minutes, 15
minutes, 15.5
minutes, 16 minutes, 16.5 minutes, 17 minutes, 17.5 minutes, 18 minutes, 18.5
minutes, 19
minutes, 19.5 minutes, 20 minutes, 20.5 minutes, 21 minutes, 21.5 minutes, 22
minutes, 22.5
minutes, 23 minutes, 23.5 minutes, 24 minutes, 24.5 minutes, 25 minutes, 25.5
minutes, 26
minutes, 26.5 minutes, 27 minutes, 27.5 minutes, 28 minutes, 28.5 minutes, 29
minutes, 29.5
minutes, 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38 minutes, 40
minutes, 42
minutes, 44 minutes, 46 minutes, 48 minutes, 50 minutes, 52 minutes, 54
minutes, 56
minutes, 58 minutes, 60 minutes, or any amount of time therebetween.
The present disclosure contemplates densified biomass material 20 being loaded
directly into receiving container 10. Alternatively, densified biomass
material 20 may be
loaded into a holder 22, which is then immersed within receiving container 10.
To allow direct contact of densified biomass material 20 with combustible
liquid 12
when holder 22 is used in the exemplary process, holder 22 may be any type of
holder that
can fit the densified feedstock to be torrefied and fit within receiving
container 10 and that is
porous to combustible liquid 12 in receiving container 10, but not to the
densified feedstock.
As such, holder 22 prevents densified biomass 20 or torrefied densified
biomass 30 contained
in holder 22 from falling outside holder 22, while allowing combustible liquid
12 to flow
through holder 22 to heat and torrefy densified biomass 20. For example,
without limitation,
holder 22 may be a wire-strainer type basket or wire mesh basket or other type
of basket with
perforations within its outer walls. It is understood that holder 22 can
withstand the heat of
combustible liquid 12 and can be heated to a temperature of up to about 320 C
for extended
periods of time.
Given that densified biomass 20 is completely submerged within combustible
liquid
12, which is heated to a temperature in a range of about 160 C to about 280 C,
or any
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temperature therebetween, densified biomass 20 is heated up to a temperature
in a range of
about 160 C to about 320 C, or any temperature therebetween, by completion of
the
torrefaction process. By way of further example, the temperature of torrefied
densified
biomass 30 at the end of the exemplary process can vary in a range of between
about 180 C
5 to about 320 C, or any temperature therebetween; between about 180 C to
about 300 C, or
any temperature therebetween; between about 200 C and about 320 C, or any
temperature
therebetween; between about 200 C and about 310 C, or any temperature
therebetween;
between about 200 C and about 300 C, or any temperature therebetween; between
about
200 C and about 290 C, or any temperature therebetween; between about 200 C
and about
10 280 C, or any temperature therebetween; between about 200 C and about
270 C, or any
temperature therebetween; between about 200 C and about 260 C, or any
temperature
therebetween; between about 200 C and about 250 C, or any temperature
therebetween;
between about 200 C and about 240 C, or any temperature therebetween; between
about
220 C and about 300 C, or any temperature therebetween; between about 220 C
and about
15 290 C, or any temperature therebetween; between about 220 C and about
280 C, or any
temperature therebetween; between about 220 C and about 270 C, or any
temperature
therebetween; between about 220 C and about 260 C, or any temperature
therebetween;
between about 220 C and about 250 C, or any temperature therebetween; between
about
220 C and about 240 C, or any temperature therebetween; or can be about 162 C,
165 C,
20 168 C, 170 C, 172 C, 175 C, 178 C, 180 C, 181 C , 182 C , 183 C , 184 C
, 185 C , 186 C ,
187 C , 188 C , 189 C , 190 C , 191 C, 192 C, 193 C, 194 C, 195 C, 196 C, 197
C, 198 C,
199 C, 200 C , 201 C, 202 C, 203 C, 204 C, 205 C, 206 C, 207 C, 208 C, 209 C,
210 C,
211 C, 212 C, 213 C, 214 C, 215 C, 216 C, 217 C, 218 C, 219 C, 220 C, 22FC,
222 C,
223 C, 224 C, 225 C, 226 C, 227 C, 228 C, 229 C, 230 C, 23FC, 232 C, 233 C,
234 C,
235 C, 236 C, 237 C, 238 C, 239 C, 240 C, 24FC, 242 C, 243 C, 244 C, 245 C,
248 C,
250 C, 252 C, 255 C, 258 C, 260 C, 262 C, 264 C, 266 C, 268 C, 270 C, 272 C,
274 C,
276 C, 278 C, 280 C, 282 C, 284 C, 286 C, 288 C, 290 C, 292 C, 294 C, 296 C,
298 C,
300 C, 302 C, 304 C, 306 C, 308 C, 310 C, 312 C, 314 C, 316 C, 318 C, 320 C,
or any
temperature therebetween. One of skill in the art will appreciate that the
temperature of
torrefied densified biomass 30 at the end of the torrefaction process, prior
to removal from
receiving container 10, will depend on the starting raw material, the time
that densified
biomass 20 is submerged within heated combustible liquid 12, the type of
combustible liquid
12 used, and the temperature of combustible liquid 12.
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During submersion of the densified biomass 20 within combustible liquid 12 and
during the torrefaction process, densified biomass 20 absorbs combustible
liquid 12 such that
the resulting torrefied densified biomass 30 retains some absorbed combustible
liquid 12. The
amount of combustible liquid 12 absorbed by the densified biomass 20 and
retained in the
post-torrefaction densified biomass 30 depends upon several different factors
including, for
example, the physico-chemical properties of the starting feedstock, the
density of the
densified biomass 20, the amount of starting feedstock, the submersion time of
the densified
biomass 20 in the combustible liquid 12, the combustible liquid 12 used, and
the temperature
of the combustible liquid 12. As will be illustrated and described further in
Examples 4 and 5,
the absorption of combustible liquid 12 by densified biomass 20 does not occur
at a constant
rate. Combustible liquid 12 is initially absorbed at a higher rate compared to
absorption rates
occurring later in the torrefaction process. For example, the rate of
absorption at the
beginning of the torrefaction process may be between about 9% to about 18% w/w
combustible liquid per mass of the input bone dry densified biomass, or any
rate
therebetween such as, without limitation, about 10%, 11%, 12%, 13%, 14%, 15%,
16%, 17%,
or any rate therebetween. Following the initial higher rate of absorption of
the combustible
liquid 12, the absorption rate decreases and remains at a fairly constant rate
for a period of
time during the torrefaction process. This lower rate occurring during the mid-
portion of the
torrefaction process may be between about 6% to about 14% w/w combustible
liquid per
mass of the input bone dry densified biomass, or any rate therebetween such
as, without
limitation, about 7%, 8%, 9%, 10%, 11%, 12%, 13%, or any rate therebetween. It
was
discovered that if densified biomass 20 is submersed in combustible liquid 12
for longer
periods of time, rate of absorption of the combustible liquid 12 by the
densified biomass 20
decreases substantially. For example, the rate of absorption during later
periods of the
torrefaction process may be between about 2% to about 10% w/w combustible
liquid per
mass of the densified biomass of the initial rate of absorption, or any rate
therebetween such
as, without limitation, about 3%, 4%, 5%, 6%, 7%, 8%, 9%, or any rate
therebetween. The
rate of absorption of combustible liquid 12 by densified biomass 20 may also
fall to a
negative rate if the densified biomass 20 is submersed within combustible
liquid 12 for an
extensive period of time. It appears that some of the combustible liquid 12
absorbed by the
densified biomass 20 during the earlier stages of the torrefaction process may
be released
from torrefied densified biomass 30 as the torrefaction process is maintained
for increasingly
extended periods of time. As disclosed above, the time ranges during which the
rate of
absorption occurs at higher rates, constant rates, lower rates of absorption,
or negative rates;
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22
i.e., loss of the combustible liquid by torrefied densified biomass 20 will
depend on one or
more of the temperature of the combustible liquid 12, the physico-chemical
properties of the
starting feedstock, the amount of starting feedstock, the combustible liquid
12, the type of
combustible liquid 12 used, and other factors. However, it is apparent that
the rate of
absorption of combustible liquid 12 by densified biomass 20 varies during the
torrefaction
process, such that, the rate of absorption is initially higher, subsequently
diminishing over
time and, eventually, potentially resulting in loss of some combustible liquid
12 absorbed
earlier in the process. Based on these findings, the duration of the
torrefaction process may be
varied to obtain torrefied densified biomass 30 with different amounts of
combustible liquid
12 absorbed therein.
The amount of time that densified biomass 20 is submerged within combustible
liquid
12 may vary depending on different variables, such as for example, the
properties of the
starting feedstock, including its size and initial temperature, the size of
receiving container
10, the amount of the starting feedstock for torrefaction, the amount of
combustible liquid 12,
the type of combustible liquid 12, and the physico-chemical properties of
torrefied densified
biomass 30 that is desired, such as the mass, amount of oil contained therein,
carbon content,
hydrophobic nature and the heat energy value (BTU per pound or GJ/t). By way
of example,
the submersion time of densified biomass 20 in combustible liquid 12 may vary
from about 2
minutes to about 120 minutes, or any amount of time therebetween; such as for
example,
from about 2 minutes to about 110 minutes, or any amount of time therebetween;
from about
2 minutes to about 100 minutes, or any amount of time therebetween; from about
2 minutes
to about 90 minutes, or any amount of time therebetween; from about 2 minutes
to about 80
minutes, or any amount of time therebetween; from about 2 minutes to about 75
minutes, or
any amount of time therebetween; from about 2 minutes to about 70 minutes, or
any amount
of time therebetween; from about 2 minutes to about 65 minutes, or any amount
of time
therebetween; from about 2 minutes to about 60 minutes, or any amount of time
therebetween; from about 2 minutes to about 55 minutes, or any amount of time
therebetween; from about 2 minutes to about 50 minutes, or any amount of time
therebetween; from about 2 minutes to about 45 minutes, or any amount of time
therebetween; from about 2 minutes to about 40 minutes, or any amount of time
therebetween; from about 2 minutes to about 35 minutes, or any amount of time
therebetween; from about 2 minutes to about 30 minutes, or any amount of time
therebetween; from about 2 minutes to about 25 minutes, or any amount of time
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23
therebetween; from about 2 minutes to about 20 minutes, or any amount of time
therebetween; from about 5 minutes to about 60 minutes, or any amount of time
therebetween; from about 5 minutes to about 55 minutes, or any amount of time
therebetween; from about 5 minutes to about 50 minutes, or any amount of time
therebetween; from about 5 minutes to about 45 minutes, or any amount of time
therebetween; from about 5 minutes to about 40 minutes, or any amount of time
therebetween; from about 5 minutes to about 35 minutes, or any amount of time
therebetween; from about 5 minutes to about 30 minutes, or any amount of time
therebetween; from about 5 minutes to about 25 minutes, or any amount of time
therebetween; from about 5 minutes to about 20 minutes, or any amount of time
therebetween; from about 5 minutes to about 15 minutes, or any amount of time
therebetween; or about 2 minutes, 2.5 minutes, 3 minutes, 3.5 minutes, 4
minutes, 4.5
minutes, 5 minutes, 5.5 minutes, 6 minutes, 6.5 minutes, 7 minutes, 7.5
minutes, 8 minutes,
8.5 minutes, 9 minutes, 9.5 minutes, 10 minutes, 11 minutes, 12 minutes, 13
minutes, 14
minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, 20
minutes, 21
minutes, 22 minutes, 23 minutes, 24 minutes, 25 minutes, 26 minutes, 27
minutes, 28
minutes, 29 minutes, 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38
minutes, 40
minutes, 42 minutes, 44 minutes, 46 minutes, 48 minutes, 50 minutes, 52
minutes, 54
minutes, 56 minutes, 58 minutes, 60 minutes, or any amount of time
therebetween.
Following submersion of densified biomass 20 in combustible liquid 12 for the
time
desired, torrefied densified biomass 30 is retrieved from receiving container
10. If densified
biomass 20 is directly loaded into receiving container 10, any type of utensil
may be used to
retrieve torrefied densified biomass 30 from receiving container 10.
Preferably, the utensil
used will limit the amount of combustible liquid 12 that is removed with
torrefied densified
biomass 30, as the present process contemplates reuse of the combustible
liquid 12. By way
of example, the utensil may be a perforated-type of utensil, such as, without
limitation, a
slotted spoon, or may be a pair of forceps, tweezers, tongs, or the like. If
holder 22 is used to
load densified biomass 20 into receiving container 10, then holder 22, along
with torrefied
densified biomass 30 contained therein, is removed from receiving container
10.
To minimize the amount of combustible liquid 12 that is removed along with
torrefied
densified biomass 30, and thereby, be able to reuse as much combustible liquid
12 as
possible, torrefied densified biomass 30, or holder 22 containing torrefied
densified biomass
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30, may be held above receiving container 10 for about 15 seconds to about 150
seconds, or
any time therebetween, to drain torrefied densified biomass 30 of combustible
liquid 12 and
drip combustible liquid 12 into receiving container 10 for reuse. For example,
without
limitation, torrefied densified biomass 30, or holder 22, may be held above
receiving
container 10 for about 15 seconds, 16 seconds, 17 seconds, 18 seconds, 19
seconds, 20
seconds, 21 seconds, 22 seconds, 23 seconds, 24 seconds, 25 seconds, 26
seconds, 27
seconds, 28 seconds, 29 seconds, 30 seconds, 31 seconds, 32 seconds, 33
seconds, 34
seconds, 35 seconds, 36 seconds, 37 seconds, 38 seconds, 39 seconds, 40
seconds, 41
seconds, 42 seconds, 43 seconds, 44 seconds, 45 seconds, 48 seconds, 50
seconds, 52
seconds, 55 seconds, 58 seconds, 60 seconds, 65 seconds, 70 seconds, 75
seconds, 80
seconds, 85 seconds, 90 seconds, 95 seconds, 100 seconds, 105 seconds, 110
seconds, 115
seconds, 120 seconds, 125 seconds, 130 seconds, 135 seconds, 140 seconds, 145
seconds,
150 seconds, or any amount of time therebetween. If time permits, a skilled
person will
appreciate that torrefied densified biomass 30, or holder 22, may be held
above receiving
container 10 for longer periods of time to maximize the amount combustible
liquid 12
retained in receiving container 10. Accordingly, the exemplary process
described herein
maximizes retention of oil or combustible liquid 12 in receiving container 10,
rather than
absorption into the torrefied densified biomass, to reduce costs of
replenishing the oil for
torrefaction with each cycle.
The exemplary process further provides a cooling step, wherein torrefied
densified
biomass 30 is placed in a cooling system 32 to cool torrefied densified
biomass 30 to near-
ambient temperatures until it can be safely handled for packaging, storing,
use, or
transportation. Cooling system 32 may be, for example, a cold water bath with
the water at a
sufficiently cold temperature to cool torrefied densified biomass 30 to a near-
ambient
temperature. For example, without limitation, the cold water bath may have
water at a
temperature of about 0 C to about 100 C, or any temperature therebetween, such
as, without
limitation, about 0 C, 2 C, 4 C, 6 C, 8 C, 10 C, 12 C, 14 C, 16 C, 18 C, 20 C,
22 C, 24 C,
26 C, 28 C, 30 C, 32 C, 34 C, 36 C, 38 C, 40 C, 42 C, 44 C, 46 C, 48 C, 50 C,
52 C, 54 C,
56 C, 58 C, 60 C, 62 C, 64 C, 68 C, 70 C, 72 C, 74 C, 76 C, 78 C, 80 C, 82 C,
84 C, 86 C,
88 C, 90 C, 92 C, 94 C, 96 C, 98 C, 100 C, or any temperature therebetween.
Torrefied
densified biomass 30 may be immersed in the cold water bath for about 0.5 to
about 20
minutes, or any amount of time therebetween, such as, without limitation, 0.5
minutes, 1
minutes, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8
minutes, 9
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minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15
minutes, 16
minutes, 17 minutes, 18 minutes, 19 minutes, 20 minutes, or any amount of time
therebetween. It is understood that torrefied densified biomass 30 may be left
in the cold
water bath for longer periods of time, and the amount of time will vary
depending on a
5 number
of factors, such as, the size of torrefied densified biomass 30, the size and
temperature of the cold water bath, the starting temperature of torrefied
densified biomass 30
(i.e., its temperature at the point it is retrieved from receiving container
10), and the desired
temperature of the torrefied densified biomass 30 for handling. The
torrefaction process
produces a hydrophobic torrefied biomass. Accordingly, cooling torrefied
densified biomass
to 30 in
water does not generally result in significant absorption of water or an
increase in
weight of the torrefied densified biomass 30. However, the amount of water
absorbed by the
torrefied densified biomass 30 is relative to the amount of time that
densified biomass 20 is
retained in hot combustible liquid 12 and the temperature of combustible
liquid 12. It is
further contemplated that torrefied densified biomass may also be cooled in a
step-wise
15
fashion, such that an initial cold water bath with water at a temperature
between about 50 C
to about 100 C, or any temperature therebetween, is used, followed by a cold
water bath at a
temperature between about 0 C to about 50 C, or any temperature therebetween.
This step-
wise cooling may increase the efficiency of the cooling step and thereby
reduce costs and
increase throughput.
20
Torrefied densified biomass 30 may be placed directly into cooling system 32
without
holder 22, or holder 22 containing torrefied densified biomass 30 therein may
be placed into
cooling system 32. Accordingly, torrefied densified biomass 30 may be
extracted from the
cold water bath in a manner similar to how it is retrieved from receiving
container 10, as
described above. The use of a cooling system 32, such as a cold water bath,
does not require
25
significant energy or resources to operate, thus providing a further cost-
savings and
efficiency. Furthermore, collection of any steam expelled during the cooling
process may also
be used in other stages of the process, as described in more detail below.
Further, as mentioned above, the amount of combustible liquid 12 absorbed and
retained within torrefied densified biomass 30 may be varied depending on
various factors,
including the duration of the torrefaction process and submersion of densified
biomass 20
within combustible liquid 12, the temperature of the combustible liquid 12,
the properties of
the starting feedstock, the amount of the starting feedstock, and the type of
combustible liquid
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12 used, amongst other factors. Consequently, the heat energy value of
torrefied densified
biomass 30 may also be tailored by adjusting the variables, such as the
duration of the
torrefaction process and submersion of densified biomass 20 within combustible
liquid 12,
the temperature of the combustible liquid 12, the properties of the starting
feedstock, the
amount of the starting feedstock, and the combustible liquid 12 used, amongst
other factors.
Another exemplary process of the present disclosure is shown in Fig. 2. In
this
embodiment, the starting raw biomass material is densified such that no
densification step is
required prior to immersion in combustible liquid 12. Densified biomass 20 can
be any
biomass material that is readily commercially available as a densified biomass
product. Other
than the initial starting material, the remaining steps of this embodiment are
the same as those
described in relation to Fig. 1.
As shown in Figs. 1 and 2, a gas collection and condenser system 40 comprising
a
plurality of pipes may be used for connecting to receiving container 10 and
cooling system
32. System 40 may comprise a series of inlets and outlets, with an inlet
disposed in each of
receiving container 10 and cooling system 32 above the liquid level of
combustible liquid 12
and the cooling water in cooling system 32, respectively. The inlet disposed
in receiving
container 10 is for collecting VOCs and steam, and the inlet disposed in
cooling system 32 is
for collecting steam upon cooling of the torrefied densified biomass. An inlet
may also be
disposed in densifier 5 or dryer 7 (or a combined dryer/densifier) to capture
any steam that is
expelled during the densification and drying processes. The mixture of VOCs
and steam may
be further processed and condensed in system 40. The mixture may be separated
into bio-
liquids and gases that contain CO, CO2 and perhaps also H2, CH4 and other
trace volatiles.
The gases may be burnt to help heat the combustible liquid 12 in receiving
container 10 or to
provide energy for dryer 7 or densifier 5 (or a combined dryer/densifier). If
the gases are used
in the exemplary processes, outlets of system 40 will be disposed within the
heat sources for
heating combustible liquid 12 and within the dryer 7 and densifier 5 (or a
combined
dryer/densifier) to assist in operating these machines. Alternatively, the
gases may be used or
sold separately as feedstock for other chemical synthesis processes. The bio-
liquids obtained
from the non-volatile vapors and steam may be reused in cooling system 32 or
potentially in a
steam generator or boiler for heating combustible liquid 12. The present
disclosure, therefore,
provides for a heat exchange system that results in a more energy-efficient
process.
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It is further contemplated that the exemplary processes described herein may
be
continuous, semi-continuous or batch processes. With a continuous, semi-
continuous or batch
process, the various steps of the process may be connected by a conveyor-type
system or
other type of system to allow continuous transporting of densified biomass 20
or holder 22
containing densified biomass 20 therein through the present processes as
described herein.
The present disclosure therefore contemplates a system for carrying out the
exemplary
torrefaction processes disclosed herein. In such a system, a conveyor or other
type of
transport system may be used to carry the raw biomass material, whether
densified to begin
with or not, through the processes described in Figs. 1 and 2. Accordingly,
the raw biomass
material 2 is brought from the densifier 5/dryer 7 or receiving container 10
through the
process to the cooling system 32, where the torrefied densified biomass 30 is
retrieved and
available for handling, transport, use, shipping, etc. Any type of continuous
system, semi-
continuous system or batch system contemplated herein is a straight-line,
simple to design,
easily operatable and efficient system, with limited complexity and
engineering required.
The exemplary processes described herein may further comprise a step of
cleaning the
torrefied densified biomass 30. This step of cleaning may comprise a screening
process,
wherein a screening device is used to separate fines and any other waste
particles from
torrefied densified biomass 30. Alternatively, this step of cleaning may
comprise a washing
step, wherein torrefied densified biomass 30 is washed in a water bath to
remove residual
combustible oil adhering to the outer surface of the torrefied densified
biomass 30. The
cleaning of the torrefied densified biomass 30 may also comprise both a
screening step and a
washing step.
Another embodiment of the present disclosure relates to an exemplary process
100
illustrated in Fig. 3 wherein a selected biomass or biosolids feedstock is
delivered to a pellet
press or briquetter 105 wherein the feedstock is densified and extruded as
pellets or pressed
into briquettes (i.e., densified biomass 20) which are transferred by a pellet
feed conveyer
110 into a torrefusion reactor 115. The supply of the selected biomass or
biosolids feedstock
to pellet press or briquetter 105 may be continuous, semi-continuous or in
batches, thereby
resulting in a continuous, semi-continuous or batch throughput process 100.
The torrefusion
reactor 115 contains a volume of heated combustible oil 12 wherein the pellets
20 are
submerged and torrefied for a selected period of time. The combustible oil 12
contained in
the torrefusion reactor 115, is maintained at a temperature from the range of
about 160 C to
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about 320 C. The torrefusion reactor 115 has components that controllably
maintain the
pellets 20 submerged in the heated combustible oil 12 while controllably
conveying the
submerged pellets 20 from the input end to the output end of the torrefusion
reactor 115. The
submerged pellets 20 are torrefied during their transport from the input end
to the output end
of the torrefusion reactor 115 via conveyor 110 (or any other suitable
conveyor belt that
allows continuous or semi-continuous transport of the pellets through the
process 100). The
duration of time for transport of the submerged pellets 20 from the input end
to the output
end of the torrefusion reactor 115 can be controllably varied from about 2
minutes to about
120 minutes (or longer if so desired). After leaving the output end of the
torrefusion reactor
115, the torrefied pellets are conveyed on conveyor 110 (or any other suitable
conveyor belt
that allows continuous or semi-continuous transport of the pellets through the
process 100) to
a cooler 120 from which they are conveyed into and through a screening device
125 which
separates fines from the torrefied pellets. Finally, the screened torrefied
pellets are conveyed
into a finished product bin 130 via conveyor 110 (or any other suitable
conveyor belt that
allows continuous or semi-continuous transport of the pellets through the
process 100).
Heat and gases produced during torrefaction of the pellets in the torrefusion
reactor
115 are collected in a torgas collection hood 160 under a vacuum force created
by torgas fan
170 which conveys the heat and torrefaction gases to the torgas burner 145.
The torgas burner
145 combines and combusts the torrefaction gases to produce heated air which
is then
conveyed to the hot side of an air-to-oil heat exchanger 150. The torgas
burner 145 and
thermal energy from the external burner is combined prior to the heat
exchanger 150. The
combustible oil contained within the torrefusion reactor 115 is maintained at
a selected
temperature by constant circulation by an oil pump 152 through an oil filter
154 and into the
cool side of the air-to-oil heat exchanger 150 wherein it is heated by the
heated air incoming
from the torgas burner 145. The heated combustible oil is then conveyed back
into the
torrefusion reactor 115. The air-to-oil heat exchanger 150 is vented 158 to
the atmosphere.
Optionally, the screened fines 135 may also be conveyed to a burner 140 for
production of
thermal energy, and the thermal energy then routed to a torgas burner 145.
Another embodiment of the present disclosure relates to an exemplary process
200
illustrated in Fig. 4 wherein a selected biomass or biosolids feedstock is
delivered to a pellet
press or briquetter 202 wherein the feedstock is densified and extruded as
pellets or pressed
into briquettes which are transferred by a pellet feed conveyer 205 into a
torrefusion reactor
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210. The supply of the selected biomass or biosolids feedstock to pellet press
or briquetter
202 may be continuous, semi-continuous or in batches, thereby resulting in a
continuous,
semi-continuous or batch throughput process 200. The torrefusion reactor 210
contains a
volume of heated combustible oil wherein the pellets are submerged and
torrefied for a
selected period of time. The combustible oil contained in the torrefusion
reactor 210, is
maintained at a temperature from the range of about 160 C to about 320 C. The
torrefusion
reactor 210 has components that controllably maintain the pellets submerged in
the heated
combustible oil while controllably conveying the submerged pellets from the
input end to the
output end of the torrefusion reactor 210 via conveyer 205 or another conveyor
belt that
allows continuous or semi-continuous transport of the pellets through the
process 200. The
submerged pellets are torrefied during their transport from the input end to
the output end of
the torrefusion reactor 210. The duration of time for transport of the
submerged pellets from
the input end to the output end of the torrefusion reactor 210 can be
controllably varied from
about 2 minutes to about 120 minutes (or longer if so desired). After leaving
the output end of
the torrefusion reactor 210, the torrefied pellets are conveyed by conveyor
205 (or any other
suitable conveyor belt that allows continuous or semi-continuous transport of
the pellets
through the process 200) into a water bath cooler 215 which receives a
constant supply of
fresh water 212. Residual combustible oil adhering to the surface of the
torrefied pellets
conveyed from the torrefusion reactor 210 is washed away from the torrefied
pellets into the
wash water which is then separated from the washed torrefied pellets. The
washed torrefied
pellets are conveyed into a finished product bin 220 by conveyor 205 (or any
other suitable
conveyor belt that allows continuous or semi-continuous transport of the
pellets through the
process 200).
Heat and gases produced during torrefaction of the pellets in the torrefusion
reactor
210 are collected in a torgas collection hood 250 under a vacuum force created
by a torgas
fan 255 which conveys the heat and torrefaction gases to a torgas burner 260.
The torgas
burner 260 combines and combusts the torrefaction gases with a supply of
thermal energy
from an external burner 262 to produce heated air which is then conveyed to
the hot side of
an air-to-oil heat exchanger 235. The combustible oil contained within the
torrefusion reactor
210 is maintained at a selected temperature by constant circulation by an oil
pump 225
through an oil filter 230 and into the cool side of the air-to-oil heat
exchanger 235 wherein it
is heated by the heated air incoming from the torgas burner 260. The heated
combustible oil
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is then conveyed back into the torrefusion reactor 210. The air-to-oil heat
exchanger 235 is
vented 237 to the atmosphere.
Either fresh water or the wash water from the water bath cooler 215 is
optionally
routed to equipment 275 that can receive an incoming biomass feedstock from a
hopper
5 referred to in Fig. 4 as a "raw salty hog" 270, that may need
desalinization processing. Such
biomass feedstocks are exemplified by hog fuel wastestreams produced from
processing of
harvested logs that have been transported on and/or stored on saltwater
waterways, which
may require desalinization. The wash water is blended with the biomass
feedstock in
desalting and dewatering equipment 275. The salinized wash water recovered
from the
10 desalting and dewatering equipment may optionally be disposed of as an
effluent 272, while
the desalted and dewatered biomass feedstock is conveyed to the pellet press
202 for
densification and extrusion as pellets.
Representative illustrations of a small scale torrefusion reactor for use as
torrefusion
reactor 115, 210 are shown in Figures 5(A), 5(B), 6(A) and 6(B). Torrefusion
reactor 115,
15 210 may comprise a mechanism for continuously or semi-continuously
conveying densified
biomass 20 through the reactor 115, 210, or for conveying densified biomass 20
in batches
through the reactor 115, 210, such as by way of conveyor 110, 205 (or any
other suitable
conveyor belt that allows continuous or semi-continuous transport of the
densified biomass
20 through process 100, 200). Conveyor 110, 205 may be hand-operated,
electronically-
20 operated, battery-operated, solar-operated, or otherwise powered to
convey densified biomass
20 into and through the torrefusion reactor 115, 210 and torrefied densified
biomass 30 out of
the torrefusion reaction 115, 210. As shown in Figures 5(B), 6(A) and 6(B),
the torrefusion
reaction may comprise holder 22 or other type of intake hopper/feeder that
operates as a
densified biomass/biosolids metering bin and comprises a notch, slit, hole,
space or any other
25 type of opening 280 at the point of contact with conveyor 110, 205
between the bottom of
holder 22 and conveyor 110, 205, such that the densified biomass 20 may be
gravity fed from
the holder 22 onto the moving conveyor 110, 205 as the conveyor moves. The
throughput of
the densified biomass 20 onto conveyer 110, 205 and through process 100, 200
may be
controlled by adjusting the size of the notch, slit, hole, space or other type
of opening 280 in
30 or at the bottom of holder 22 and/or by adjusting the amount, size,
weight and thickness of
the bed of densified biomass 20 placed in holder 22. The direction of rotation
of conveyor
110, 205 is shown in Figure 6(B). Arrow (A) represents the direction of
rotation of conveyor
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110, 205 to carry the densified biomass 20 into the combustible liquid for a
certain period of
time and then conveying the torrefied densified biomass 30 out of the
combustible liquid.
Arrow (13), shown in shadow, indicates that conveyor 110, 205 may be an
endless conveyor
belt that can continuously or semi-continuously move densified biomass 20
through the
torrefaction processes disclosed herein. It will be understand that in a full-
scale, operational
throughput process, this conveyor 110, 205 may continue to convey the
torrefied densified
biomass 30 into water bath cooler 215. An exemplary size for a small scale
torrefusion
reactor 115, 210 is shown in Table A below.
Table A: Torrefusion Reactor Size
Reactor Length (feet) 36
Reactor Width (feet) 5
Conveyor Thickness (inches) 4
Retention/Submersion time (minutes) 15
Bulk Density (lbs/ft3) 40
Fill Factor (%) 100%
Mass of Conveyor Mat (lbs/ft3) 2,400
Mass of Conveyor Mat (MT) 1.09
Conveyor Cycles per Hour 4
Input per Hour (MT) 4.355
Output per Hour @ 80% (MT) 3.484
Operating Hours per Day 24.00
Operating Hours per Week 7.00
Operating Weeks per Year 50.00
Uptime (%) 80
Total Capacity (input) (MT/annum) 29,262
Total Capacity (output) (MT/annum) 23,410
Torrefied densified biomass 30 produced by the processes described herein
comprises
about 2% to about 25% w/w combustible liquid following torrefaction (i.e.,
torrefied
densified biomass 30 absorbs about 2% to about 25% w/w combustible liquid
during the
process), or any amount therebetween. For example, without limitation, the
amount of
combustible liquid 12 absorbed and retained within torrefied densified biomass
30 may be
about 2% to about 25% w/w combustible liquid, or any amount therebetween;
about 2% to
about 24% w/w combustible liquid, or any amount therebetween; about 2% to
about 23%
w/w combustible liquid, or any amount therebetween; about 2% to about 22% w/w
combustible liquid, or any amount therebetween; about 2% to about 21% w/w
combustible
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liquid, or any amount therebetween; about 2% to about 20% w/w combustible
liquid, or any
amount therebetween; about 2% to about 19% w/w combustible liquid, or any
amount
therebetween; about 2% to about 18% w/w combustible liquid, or any amount
therebetween;
about 2% to about 17% w/w combustible liquid, or any amount therebetween; such
as, for
example, 3% w/w combustible liquid, 4% w/w combustible liquid, 5% w/w
combustible
liquid, 6% w/w combustible liquid, 7% w/w combustible liquid, 8% w/w
combustible liquid,
9% w/w combustible liquid, 10% w/w combustible liquid, 11% w/w combustible
liquid, 12%
w/w combustible liquid, 13% w/w combustible liquid, 14% w/w combustible
liquid, 15%
w/w combustible liquid, 16% w/w combustible liquid, or any amount
therebetween.
Torrefied densified biomass 30 produced by the processes of the present
disclosure
may further have a heat energy value of about 6,000 BTU per pound on a bone
dry basis to
about 13,000 BTU per pound on a bone dry basis, or any heat energy value
therebetween, for
example, from about 6,000 BTU per pound on a bone dry basis to about 12,000
BTU per
pound on a bone dry basis, or any heat energy value therebetween; from about
6,000 BTU per
pound on a bone dry basis to about 11,000 BTU per pound on a bone dry basis,
or any heat
energy value therebetween; from about 6,000 BTU per pound on a bone dry basis
to about
10,000 BTU per pound on a bone dry basis, or any heat energy value
therebetween; from
about 6,000 BTU per pound on a bone dry basis to about 9,000 BTU per pound on
a bone dry
basis, or any heat energy value therebetween; or from about 9,000 BTU per
pound on a bone
dry basis to about 13,000 BTU per pound on a bone dry basis, or any heat
energy value
therebetween; such as, for example, about 9,500 BTU per pound on a bone dry
basis; about
10,000 BTU per pound on a bone dry basis; about 10,500 BTU per pound on a bone
dry
basis; about 11,000 BTU per pound on a bone dry basis; about 11,500 BTU per
pound on a
bone dry basis; about 12,000 BTU per pound on a bone dry basis; about 12,500
BTU per
pound on a bone dry basis; about 13,000 BTU per pound on a bone dry basis, or
any heat
energy value therebetween. Alternatively, torrefied densified biomass 30 may
comprise a
heat energy value of about 22 GJ/t on a bone dry basis to about 27 GJ/t on a
bone dry basis,
or any heat energy value therebetween, for example, from about 22 GJ/t on a
bone dry basis
to about 26.5 GJ/t on a bone dry basis or any heat energy value therebetween;
from about 22
GJ/t on a bone dry basis to about 26 GJ/t on a bone dry basis or any heat
energy value
therebetween; from about 22 GJ/t on a bone dry basis to about 26 GJ/t on a
bone dry basis or
any heat energy value therebetween; from about 22 GJ/t on a bone dry basis to
about 25 GJ/t
on a bone dry basis or any heat energy value therebetween; from about 22 GJ/t
on a bone dry
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basis to about 24 GJ/t on a bone dry basis or any heat energy value
therebetween; or from
about 22 GJ/t on a bone dry basis to about 23 GJ/t on a bone dry basis, or any
heat energy
value therebetween.
The torrefied densified biomass 30 produced by the processes disclosed herein
may
also have a carbon content of about 50 carbon % on a bone dry basis to about
65 carbon % on
a bone dry basis, or any amount therebetween. For example, without limitation,
the carbon
content of the torrefied densified biomass 30 may be about 51 carbon % on a
bone dry basis,
52 carbon % on a bone dry basis, 53 carbon % on a bone dry basis, 54 carbon %
on a bone
dry basis, 55 carbon % on a bone dry basis, 56 carbon % on a bone dry basis,
57 carbon % on
a bone dry basis, 58 carbon % on a bone dry basis, 59 carbon % on a bone dry
basis, 60
carbon % on a bone dry basis, 61 carbon % on a bone dry basis, 62 carbon % on
a bone dry
basis, 63 carbon % on a bone dry basis, 64 carbon % on a bone dry basis, 65
carbon % on a
bone dry basis, or any amount therebetween.
As disclosed above, the amount of combustible liquid 12 absorbed and retained
within
torrefied densified biomass 30 may vary depending on one or more factors
exemplified by the
duration of the torrefaction process, submersion of densified biomass 20
within the
combustible liquid 12, the temperature of the combustible liquid 12, the
physico-chemical
properties of the starting feedstock, the amount of the starting feedstock,
and the type of
combustible liquid 12 used, amongst other factors. Consequently, the heat
energy value of
torrefied densified biomass 30 and any other physico-chemical property of the
torrefied
densified biomass 30, such as the carbon content, or the hydrophobic nature of
the torrefied
densified biomass 30, may also be tailored by adjusting the one or more
variables such as the
duration of the torrefaction process, submersion of densified biomass 20
within combustible
liquid 12, the temperature of the combustible liquid 12, the properties of the
starting
feedstock, the amount of the starting feedstock, and the type of combustible
liquid 12 used,
amongst other factors.
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EXAMPLES
The following examples are provided to enable a better understanding of the
disclosure described herein.
Example 1:
Materials and Methods
In this example, a small test unit was designed for testing purposes. The test
unit
consisted of: a small container for holding a combustible liquid, such as
vegetable oil; a gas
burner, on which to place the small container; and a wire basket with a
contour of the small
container, such that the wire basket fit within the inner walls of the small
container. In
addition, a small scale capable of measuring up to 10 kgs in 0.001 kg
increments and a
thermocouple and temperature gauge was used for weight and temperature
calculations,
respectively.
For this example, 10 kilograms of densified softwood pellets made from a blend
of
spruce, pine and fir were tested. The 10 kilograms were divided into 1
kilogram samples
(using the small scale for measuring), and 1 sample was set aside for testing
purposes. As an
initial step, the small container was placed on a scale and the net weight of
the empty small
container was measured. Vegetable oil was then poured into the small container
and the total
weight of the small container plus vegetable oil was measured, thereby
providing a net
weight for the vegetable oil. One kilogram of unheated oil was set aside for
additional
measurements.
Once the measurements of the vegetable oil were complete, the gas burner was
turned
on to a temperature of about 270 C, and the temperature of the vegetable oil
in the small
container was monitored using the thermocouple and temperature gauge. After
the
temperature of the vegetable oil was stabilized at about 260 C to about 270
C, a 1-Kg
sample of densified wood pellets was loaded into the wire strainer basket and
submerged in
the heated vegetable oil in the small container for about 5 minutes. The wire
strainer basket
with the densified wood pellets contained therein was then removed from the
vegetable oil in
the small container, and allowed to drain and drip dry over the small
container for 5 minutes.
The torrefied densified biomass was retrieved from the wire strainer basket
and its weight
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measured, without submersing in a cold water, to avoid any water absorption by
the torrefied
densified biomass and contamination of the results. The net weight loss or
gain of the sample
was then calculated by comparing to the starting weight of the densified wood
pellets, on a
dry basis. The net weight of the used oil was also measured by measuring the
small container
5
containing the used oil and subtracting the weight of the small container. Oil
loss by
absorption and mass loss of pellets was calculated. This process was repeated
another 8
times, each with a 1 kilogram sample of densified wood pellets. The total
weight of the small
container containing the oil was measured prior to each experiment. One
kilogram of the used
vegetable oil in the small container was collected for additional testing
purposes.
10 The
resulting torrefied densified biomass from all 9 test experiments were
collected
and mixed together to form a sample batch. One kilogram of the sample batch
was collected
for testing.
Results:
The results from two sample batches prepared according to the process
described for
15 Example
1 are shown in Table 1. The test results indicated that with about 5 minutes
in a
vegetable oil heated to about 260 C to about 270 C, densified wood pellets
increased in
weight by an average of about 10% and increased in BTU value by an average of
15%. In
addition, the torrefied wood pellets were found to be hydrophobic and to have
increased
grindability (i.e., high Hardgrove Grindability Index) as compared to
untorrefied wood
20
pellets. "Hardgrove Grindability Index" ("HGI") is a measure for grindability
of coal.
Grindability is indicated using the unit H, for example, "40 H" or "55 H." A
higher HGI
value indicates a more easily pulverized or more grindable product.
As shown in Table 1 below, the lower heating value (LHV) of two sample batches
of
torrefied pellets obtained from the process were 23.11 and 22.76 GJ/ton,
respectively. This
25
represents an increase in LHV of approximately 14.8% for sample 1 and
approximately
16.1% for sample 2. Those skilled in the art will know that an average LHV for
wood pellet
fuel ranges from a low of 18.14 GJ/ton to a high of 19.72 GJ/ton, making
torrefied wood
pellets of the disclosed process to be approximately 17.5% higher in heat
value compared to
good quality biofuel.
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Table 1:
Measurements Starting Densified Wood Torrefied Wood Pellet Torrefied Wood
Pellet
Pellet #1 #1 #2
As Received Dry Basis As Received Dry Basis As Received Dry Basis
Basis Basis Basis
Weight 1 kg 1 kg 1 kg
% Moisture* 7.00 1 0 2.78 I. 0 0.59 1 0
Calorific Value
(Gross)
i .
Btu/lb 8336 ! 8963 9786 ! 10066 9934 ! 9993
Kcal/kg 46314979 5437 1 5592 5519 1 5552
1
GJ/ton 19.39 20.85 22.76 1 23.41 23.11 23.24
% Carbon =
.
. 55.46 i 55.79
. :
= !
% Hydrogen .=
=
.
.
. 6.58 1 6.62
.=
=
(excludes H in :
=
. I
=== i
36.92moisture) .
=
:
% Nitrogen . 0.09 1 0.09
=
% Sulphur 0.02 , 0.02
.==!
% Ash '
= 0.56 !
0.56
:
=
%Oxygen . 36.70 1 36.92
: i
% Hydrogen ..=='
.
.
.
! 6.65 ---
=
(includes H in .=
-
.===
. I
moisture) :
' .
=
=
* "% Moisture" for the "Torrefied Wood Pellets" refers to the amount of
water in the
torrefied wood pellets immediately after the torrefaction process (i.e., after
drip drying
for 5 minutes).
"Starting Densified Wood Pellet" is the sample that was initially set aside
for testing
purposes.
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Example 2:
Materials and Methods
In this example, a coastal hemlock briquette was quartered and each quarter
was used
for testing. Three of the quarters were used in the torrefaction process and
one quarter was set
aside. The initial weight of the quartered briquettes used in the torrefaction
process is set out
in Table 2 below.
The small test unit, as described above for Example 1, was used in this
example. As
an initial step, the small container was placed on a scale and the net weight
of the empty
small container was measured. Vegetable oil was then poured into the small
container and the
total weight of the small container plus vegetable oil was measured, thereby
providing a net
weight for the vegetable oil. One kilogram of unheated oil was set aside for
additional
measurements.
After the measurements of the vegetable oil were complete, the gas burner was
turned
on to a temperature of about 260 C, and the temperature of the vegetable oil
in the small
container was monitored. After the temperature of the vegetable oil was
stabilized at about
260 C, a quarter briquette sample was loaded into the wire strainer basket and
submerged in
the heated vegetable oil in the deep fryer for about 7.5 minutes. The wire
strainer basket with
the quarter briquette sample contained therein was then removed from the
vegetable oil in the
small container and allowed to drain over the deep fryer for 5 minutes. The
torrefied
densified biomass was then retrieved from the wire strainer basket and its
weight measured,
without submersing in a cold water, to avoid any water absorption by the
torrefied densified
biomass and contamination of the results. The net weight loss or gain of the
sample was then
calculated by comparing to the starting weight of the densified wood pellets,
on a dry basis.
The net weight of the used oil was also measured by measuring the small
container
containing the used oil and subtracting the weight of the small container. Oil
loss by
absorption and mass loss of pellets was calculated. This process was then
repeated another 2
times for the other 2 quarter briquette samples, with the exception that 1
quarter briquette was
torrefied for about 10 minutes, and the other for about 15 minutes. The total
weight of the
small container containing the oil was measured prior to each experiment. One
kilogram of
the used vegetable oil in the small container was collected for additional
testing purposes.
The resulting torrefied densified biomass from each experiment was collected
for testing.
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Results:
The results for Example 2 are shown in Table 2. The test results indicated
that all
quarter briquette samples increased in weight, on average, by about 10% as
compared to the
original weight of the respective quarter briquette, representing the
approximate amount of
oil absorbed by the samples. In addition, the torrefied wood pellets were
found to be
hydrophobic and to have increased grindability (i.e., high Hardgrove scale
score) as
compared to untorrefied wood pellets.
Table 2: Quartered Briquettes Experiment
Sample 1 Sample 2 Sample 3
Starting Weight (g) 1139.85 140.85 149.60
Finished Weight (g) 156.40 155.25 165.75
Net Increase in Weight (%) 10.58% 9.28% 9.74%
Starting Temp. of Oil (SC) _ 222.00 269.00 266.00
Ending Temp. of Oil (SC) I 266.00 270.00 E 267.00
Retention Time in Oil (mins) 15.00 7.50 10.00
Example 3:
Materials and Methods
In this example, 2 1-Kg samples of densified softwood pellets made from a
blend of
spruce, pine and fir were tested in the small test unit described above in
Example 1.
As an initial step, the small container was placed on a scale and the net
weight of the
empty small container was measured. Vegetable oil was then poured into the
small container
and the total weight of the small container plus vegetable oil was measured,
thereby
providing a net weight for the vegetable oil. One kilogram of unheated oil was
set aside for
additional measurements.
After the measurements of the vegetable oil were complete, the gas burner was
turned
on to a temperature of about 250 C to about 260 C, and the temperature of the
vegetable oil
in the small container was monitored. After the temperature of the vegetable
oil was
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stabilized at about 250 C to about 260 C, a 1-kilogram sample of densified
wood pellets was
loaded into the wire strainer basket and submerged in the heated vegetable oil
in the small
container for about 20 minutes for the first sample. The wire strainer basket
with the
densified wood pellets contained therein was then removed from the vegetable
oil in the
small container and allowed to drain over the deep fryer for 5 minutes. The
torrefied
densified biomass was then retrieved from the wire strainer basket and its
weight measured,
without submersing in a cold water bath, to avoid any water absorption by the
torrefied
densified biomass and contamination of the results. The net weight loss or
gain of the sample
was then calculated by comparing to the starting weight of the densified wood
pellets, on a
dry basis. The net weight of the used oil was also measured by measuring the
small container
containing the used oil and subtracting the weight of the small container. Oil
loss by
absorption and mass loss of pellets was calculated.
After the above process, the second 1-kg sample was loaded into the wire
strainer
basket and submerged in the heated vegetable oil in the small container for
about 30 minutes.
The wire strainer basket with the densified wood pellets contained therein was
then removed
from the small container and allowed to drain over the deep fryer for 5
minutes. The net
weight loss or gain of the sample was then calculated by comparing to the
starting weight of
the densified wood pellets, on a dry basis. The net weight of the used oil was
also measured
by measuring the small container containing the used oil and subtracting the
weight of the
small container. Oil loss by absorption and mass loss of pellets was
calculated. One kilogram
of the used vegetable oil in the deep fryer was collected for additional
testing purposes.
Results:
It was found that with 20 minutes in a vegetable oil heated to about 260 C to
about
270 C, torrefied pellets had a net loss of weight of about 2.20%. With 30
minutes in heated
vegetable oil, it was found that torrefied pellets had a net weight loss of
about 6.16%. In
addition, the torrefied wood pellets were hydrophobic and had increased
grindability (i.e.,
high Hardgrove scale score) as compared to untorrefied wood pellets.
Without wishing to be bound by theory, it is thought that some oil absorption
occurs
during the first few minutes of torrefaction, which may result in a net
increase in weight of
the biomass. Following the first few minutes, the biomass is increasingly
torrefied, thereby
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expelling VOCs and losing weight, resulting in a torrefied densified biomass
that has a net
weight loss as compared to the initial starting material.
Example 4:
Materials and Methods
5 In this
example, 4 different samples of densified softwood pellets made from a blend
of spruce, pine and fir, each weighing about 0.5 kg, were tested using the
small test unit
described in Example 1. Vegetable oil was heated to 220 C to about 240 C in
the small
container. The weight of the small container was measured before it was filled
with oil and
after it was filled with oil to determine the weight of the oil prior to the
torrefaction process.
10 One of
the 4 different samples was submerged in the oil for a pre-determined amount
of time,
and then allowed to drip dry over the small container for about 5 minutes. The
small
container containing the oil was measured again following the torrefaction
process to
determine the amount of oil absorbed by the sample. This procedure was
repeated for the
three other samples.
15 Results
The results indicated that there was less absorption with more time in the
heated oil,
as described above in Example 3. As shown in Table 3 below, sample 1, which
was torrefied
for about 10 minutes in the hot vegetable oil, showed about 9.6% oil
absorption, and sample
2, which was torrefied for about 15 minutes in the hot vegetable oil, showed
about 6.7% oil
20 absorption.
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Table 3: Oil Absorption During Torrefaction
Sample 1 Sample 2
Sample Weight ¨ at start 0.5 0.5
.=
Moisture Content* 4%
4%
Sample Weight ¨at start; bone dry basis 0.4808 0.4808
Sample Weight ¨ at end 0.45 0.474
Process Time 15 10
Change in Weight of Sample -6% =
-1%
=
Oil Weight ¨ at start 2.968 ====
2.926
Oil Weight ¨ at end 2.936
= 2.88
=
% Absorption of Oil by Sample 6.6556%
9.5674%
(bone dry basis starting weight)
"Moisture Content" refers to the amount of water (in %) in the torrefied wood
pellets
immediately after the torrefaction process (i.e., after drip drying for 5
minutes).
Example 5:
Materials and Methods
In this example, 4 different samples of densified softwood pellets made from a
blend
of spruce, pine and fir were tested, with each sample having a starting weight
of 250 grams
(0.250 kg). Each sample was tested using the method as described above in
Example 1 and
the temperature, time and weight parameters as specified below in Table 4.
Results
The results indicated that the rate of absorption of the oil by the pellets
varied over
time. As shown in Table 4 below, sample 1, which was torrefied for about 15
minutes in the
hot vegetable oil, showed about 14.31% oil absorption per mass input of bone
dry pellets;
sample 2, which was torrefied for about 30 minutes in the hot vegetable oil,
showed about
14.00% oil absorption per mass input of bone dry pellets; sample 3, which was
torrefied for
about 45 minutes in the hot vegetable oil, showed about 13.88% oil absorption
per mass input
of bone dry pellets; and sample 4, which was torrefied for about 60 minutes in
the hot
vegetable oil, showed about 11.87% oil absorption per mass input of bone dry
pellets.
As shown in Fig. 7, the oil absorption initially occurred at a higher rate
during the first
few minutes of torrefaction, after which the rate of absorption decreased and
then remained at
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a constant rate for a period of time. As the torrefaction period progressed
further, the rate of
absorption stopped and then showed negative values indicating that oil was
expelled from the
torrefied biomass during the extended periods of torrefaction. In this
example, the highest
rate of absorption occurred during the first 15 minutes of torrefaction after
which, the rate of
absorption of oil slowed and then remained at a constant rate through 45
minutes of
torrefaction, after which time, it appears that the densified biomass began
expelling oil
previously absorbed by the densified biomass.
Fig. 7 also shows that the heat value of the torrefied pellets following the
torrefaction
process increased substantially between 0 and 15 minutes of the torrefaction
process, then
to increased slowly and fairly consistently between 15 minutes and 45
minutes of torrefaction,
and eventually began to decrease after 45 minutes of torrefaction. The "heat
value of samples
¨ at end" in Table 4 and "heat value of finished product" in Fig. 7 is the
total of the torrefied
biomass plus the absorbed oil. Accordingly, the results of this example
suggest that as
pelleted biomass torrefies, the biomass expels oil (less oil in the finished
product means less
heat value in the finished product derived from oil). Since there is a net
gain in heat value of
the torrefied pellets over the long term, even with the expulsion of oil, the
biomass itself is
gaining heat value during the process and it is not simply due to oil
absorption.
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Table 4: Oil Absorption and Heat Value for Different Submersion Times in
Canola Oil
Heated to 270 C
Sample Sample Sample Sample 4
1 I 2 I 3
Submersion time (minutes) 15 30 45 60
Sample Weight - at start (g) 250.00 250.20 250.80 250.45
Moisture content (%) 1.82 1.82 1.82 1.82
Sample Weight -at start; bone dry basis (g) 245.45 245.65 246.24
245.89
Sample Weight - at end (g) 247.5 242.2 236.15 233.5
Oil Weight-at start (g) 650 612.4 572.4 651.7
Oil Weight-at end (g) 612.4 573.35 531.7 612.6
Gross Oil Used (g) 37.6 I 39.05 I 40.7 I 39.1
Oil Evaporation (g) 2.47 4.65 6.52 9.90
Net Oil Absorbed (g) 35.13 34.40 I 34.18 1 29.20
% Absorption of Oil by Sample 14.31 14.00 13.88 1 11.87
(bone dry basis starting weight)
=
Heat Value of Samples - at start (GJ/T @ 5% 18.00 18.00 18.00
18.00
MC)
Heat Value of Samples - at end (GJ/T) 24.10 24.56 24.85 24.75
"Moisture Content" refers to the amount of water (in %) in the torrefied wood
pellets
immediately after the torrefaction process (i.e., after drip drying for 5
minutes).
Example 6:
Materials and Methods
In this example, 20 kilograms of densified softwood pellets made from a blend
of
spruce, pine and fir (SPF wood pellets) were tested. The 20 kilograms were
divided into 1
kilogram samples, and all 20 of the 1 kilogram samples were tested using the
method as
described above in Example 1 for a specific temperature (i.e., either 240,
245, 250, 255, 250,
265 or 270 C) and for a specific submersion time (i.e., either 10, 15, 20, 25
or 30 minutes) at
each temperature, with the exception that a PITCO commercial deep fryer was
used for the
process (rather than a small container with a gas burner). In addition, each
sample was cooled
in a water bath following the torrefaction process for 5 minutes, then removed
from the cold
water bath and allowed to drain for 5 minutes before collecting the sample in
a large tub. The
method was repeated for the 20 1-kg samples for each different temperature and
submersion
time condition. Accordingly, for each temperature and submersion time
combination, the
method was repeated 20 times with a 1-kg sample each time. In addition, 10 1-
kg samples
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were tested using the method as described above in Example 1 at 280 C for 30
minutes and 6
1-kg samples were tested using the method as described above in Example 1 at
290 C for 30
minutes; that is, the method was repeated 10 times for the temperature-time
combination of
280 C for 30 minutes, and the method was repeated 6 times for the temperature-
time
combination of 290 C for 30 minutes, and the results for each temperature-time
combination
were averaged.
The resulting torrefied densified biomass from the different test experiments
for each
temperature-time condition were collected and mixed together to form a sample
batch. One
kilogram of the sample batch was collected for testing. The resulting 1-kg
sample batch was
to analyzed to determine the heat values of the torrefied pellets after
each temperature-time
condition.
Results
The data for this Example 6 are shown in Tables 5-13 and reflected in Figures
8 and
9. This Example 6 substantiates the findings in Example 5 (Table 4 and Figure
7). The results
indicated that the submersion/retention time in the heated canola oil and the
temperature of
the heated oil substantially correlated with the heat value of the torrefied
wood pellet at the
end of the process. As shown in Tables 5-13 below, generally, the higher the
temperature of
the canola oil and the longer the time retained in the heated canola oil, the
greater the heat
value of the torrefied pellets following the torrefaction process.
The highest heat energy value was obtained when densified pellets were
submersed in
290 C canola oil for 30 minutes (26.04 GJ/t on a bone dry basis) and the
lowest heat energy
value was obtained when densified pellets were submersed in 240 C canola oil
for 10 minutes
(22.78 GJ/t on a bone dry basis). All heat energy values for the torrefied
pellets were greater
than the heat energy value calculated for densified biomass that was not
torrefied (i.e., 20.49
GJ/t on a bone dry basis). Torrefying pellets at 250 C produced a slightly
higher heat energy
value than when torrefying pellets at 255 C at every time point measured.
Moreover, a
submersion time of 20 minutes produced the highest heat energy value when
using canola oil
at a temperature of 265 C. This data, therefore, indicated that the
torrefaction process may be
tailored as desired by varying the temperature of the canola oil and the time
submersed in the
heated oil.
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Table 5: Heat Value of Torrefied Wood Pellets Before and After Torrefusion at
240 C
Measurements Before Torrefusion Torrefusion Torrefusion Torrefusion
Torrefusion
Torrefusion for 10 mins. for 15 mins. for 20 mins.
for 25 mins. for 30 mins.
Wet I Thy Wet Dry Wet I Dry Wet ! Thy Wet I
Dry Wet ! Dry
Basis Basis Basis i Basis Basis Basis Basis i Basis Basis
Basis Basis i Basis
Weight 1 kg 1 kg 1 kg 1 kg 1 kg 1 kg
% Moisture" 5.66 0 6.05 0 4.92 I 0 5.2 0 4.12 0
3.31 0
% Ash 0.42 I 0.44 0.38 I 0.41 0.37 I 0.39 0.34 I 0.36
0.37 I 038 0.35 I 0.36
`)/0 Volatile 79.99 84.79 79.81 84.95 81.19 i 85.39 80.26 !
84.66
Matter I I 81.28 i 84.77 81.4
84.19
% Fixed 13.93 I 14.77 13.76 I 14.64 13.52 I 14.22 14.2
14.98
Carbon
14.23 I 14.85 14.94 15.45
`)/0 Sulphur 0.03 0.04 0.02 0.02 0.02 0.02 0.01 0.01
0.01 0.01 0.01 0.01
Calorific
Value (Gross)
Btu/lb 8309 I 8807 9202 I 9794 9437 I 9925 9505 I 10026 9646
I 10060 9791 I 10127
Kcal/kg 4616 I 4893 5112 I 5441 5243 I 5514 5281 I 5570
5359 I 55.89 5440 I 5626
GJ/T 1933. 2049. 214 22.78 21.95 23.09 22.11 23.32 22.44 23.4 22.77
23.55
`)/0 Carbon 47.76 50.62 51.48 54.8 52.32 I 55.03 52.65
55.53 53.19 55.47 53.85 55.69
% Nitrogen 0.068 I 0.073 0.032 I 0.034 0.019 I 0.020 0.035 0.037
0.036 0.038 0.044 0.045
%Oxygen 40.36 42.78 35.75 38.05 35.97 37.83 35.36 37.31 35.80 37.35 35.91
37.13
"% Moisture" with respect to the "Torrefied Wood Pellets" on a "Wet Basis"
refers to
the amount of water (in %) in the sample following cooling in the water bath
for 5
minutes and then draining for 5 minutes, as described in the Methods.
5 Table 6: Heat Value of Torrefied Wood Pellets Before and After
Torrefusion at 245 C
Measurements Before Torrefusion Torrefusion Torrefusion Torrefusion
Torrefusion
Torrefusion for 10 mins. for 15 mins. for 20 mins.
for 25 mins. for 30 mins.
Wet Thy Wet Dry Wet Dry Wet Thy Wet Dry Wet Dry
Basis Basis Basis Basis Basis Basis Basis Basis Basis Basis Basis Basis
Weight 1 kg I 1 kg I 1 kg I 1 kg I 1 kg I 1 kg I
% Moisture" 5.66 I 0 7.28 I 0 6.76 I 0 4.9 0 5.17
0 4.87 0
`)/0 Ash 0.42 0.44 0.32 0.34 0.35 0.37 0.41 0.43
0.41 0.43 0.39 0.41
`)/0 Volatile 79.99 84.79
Matter 79.1 85.31 78.77 84.48 80.82 84.98 79.91 84.27 80.1
84.2
% Fixed 13.93 I 14.77 =
Carbon 13.3 14.35 14.12 15.15 13.87 ! 14.59
14.51 15.3 14.64 ! 15.39
`)/0 Sulphur 0.03 0.04 0.01 0.01 0.01 0.01 0.01 0.01
0.02 0.02 0.02 0.02
Calorific
Value (Gross)
Btu/lb 8309 8807 9260 9987 9360 10039 9583 10076 9619 10144 9702 10198
Kcal/kg 4616 4893 5145 5548 5200 5577 5324 5598 5344 5635 5390 5666
GJ/T 1933. 2049. 21.54 23.23 21.77 23.35 2229 I
23.44 22.37 I 23.59 22.57 I 23.72
`)/0 Carbon 47.76 50.62 51.01 55.01 51.69 I 55.44 52.99
55.72 52.99 I 55.88 53.04 55.75
% Nitrogen 0.068 I 0.073 0.040 I 0.043 0.040 I 0.043 0.037
I 0.039 0.036 I 0.038 0.032 I 0.033
%Oxygen 40.36 I 42.78 35.10 I 37.87 34.84 I 37.37 35.32
I 37.14 34.99 I 36.90 35.28 I 37.09
"% Moisture" with respect to the "Torrefied Wood Pellets" on a "Wet Basis"
refers to
the amount of water (in %) in the sample following cooling in the water bath
for 5
minutes and then draining for 5 minutes, as described in the Methods.
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Table 7: Heat Value of Torrefied Wood Pellets Before and After Torrefusion at
250 C
Measurements Before Torrefusion Torrefusion Torrefusion Torrefusion
Torrefusion
Torrefusion for 10 mins. for 15 mins. for 20 mins.
for 25 mins. for 30 mins.
Wet I Thy Wet i Dry Wet I Dry Wet ! Thy Wet I
Dry Wet ! Dry
Basis Basis Basis i Basis Basis Basis Basis i Basis Basis
Basis Basis i Basis
Weight 1 kg : 1 kg : 1 kg : 1 kg : 1 kg : 1 kg :
`)/0 Moisture" 5.66 i 0 5.83 i 0 6.42 1 0 7.93 I 0 5.32 I 0
4.91 I 0
% Ash 0.42 I 044 0.36 0.38 0.38 I 0.41 0.4 I 0.43
0.4 I 042 0.41 I 043
1
`)/0 Volatile 79.99 i 84.79 , =
Matter 1 7943 1 84.35 79.35 1 84.8 78.03 I 84.75
79.89 i 84.39 79.71 I 83.83
I
% Fixed 13.93 I 14.77 I ! I !
Carbon 14.38 1 15.27 13.85 1 14.79 13.64 1 14.82
14.39 1 15.19 14.97 1 15.74
`)/0 Sulphur 0.03 1 0.04 0.02 1 0.02 0.02 1 0.02 0.02 1 0.02
0.02 1 0.02 0.01 1 0.01
Calorific
Value (Gross)
Btu/lb 8309 1 8807 9411 1 9994 9459 1 10107 9447 1 10261 9735
1 10283 9849 1 10358
Kcal/kg 4616 1 4893 5228 1 5552 5255 1 5615 5248 1 5701
5408 1 5713 5472 1 5754
GJ/T 1933. 1 2049. 21.89 1 23.25 22 1 23.51
21.97 1 23.87 22.64 1 23.92 22.91 1 24.09
`)/0 Carbon 47.76 I 50.62 51.67 1 54.87 51.96 I 55.52 51.48
I 55.91 52.93 I 55.91 53.61 I 56.38
% Nitrogen 0.068 1 0.073 0.040 1 0.042 0.038 1 0.041 0.034 1 0.037
0.034 1 0.036 0.036 1 0.038
%Oxygen 40.36 1 42.78 35.79 1 38.01 34.89 1 37.29 33.93
1 36.85 34.90 1 36.85 34.59 1 36.38
* "% Moisture" with respect to the "Torrefied Wood Pellets" on a "Wet
Basis" refers to
the amount of water (in %) in the sample following cooling in the water bath
for 5
minutes and then draining for 5 minutes, as described in the Methods.
Table 8: Heat Value of Torrefied Wood Pellets Before and After Torrefusion at
255 C
Measurements Before Torrefusion Torrefusion Torrefusion Torrefusion
Torrefusion
Torrefusion for 10 mins. for 15 mins. for 20 mins.
for 25 mins. for 30 mins.
Wet Thy Wet Dry Wet Dry Wet Thy Wet Dry Wet Dry
Basis Basis Basis Basis Basis Basis Basis Basis Basis Basis Basis Basis
Weight 1 kg I 1 kg I 1 kg I 1 kg ! 1 kg ! 1 kg !
% Moisture" 5.66 1 0 8.63 1 0 9.5 1 0 7.17 1 0
6.86 1 0 6.77 1 0
`)/0 Ash 0.42 1 0.44 0.39 1 0.42 0.37 I 0.41 0.44 1 0.48
0.51 1 0.55 0.41 1 0.44
`)/0 Volatile 79.99 84.79
Matter 77.87 85.23 76.01 83.99 78.75 84.84 78.09 83.84 78.49
84.2
`)/0 Sulphur 0.03 1 0.04 0.01 0.01 0.01 i 0.02 0.02 i
0.02 0.01 i 0.01 0.02 i 0.03 I 1 i 1 i
Calorific
1 !
Value (Gross)
. i
Btu/lb 8309 1 8807 9130 1 9992 9059 1 10011 9437 1 10166 9447
1 10143 9564 1 10259
Kcal/kg 4616 1 4893 5072 1 5551 5033 1 5561 5243 1 5648
5248 1 5635 5313 1 5700
GJ/T 1933. I 2049. 2124 I 23.24 21.07 I 23.28
21.95 1 23.65 21.97 1 23.59 2225 1 23.86
`)/0 Carbon 47.76 1 50.62 51.14 1 55.97 51.07 1 56.43 52.63
1 56.69 52.96 1 56.87 53.5 1 57.38
% Nitrogen 0.068 I 0.073 0.066 I 0.073 0.067 I 0.074 0.063 1 0.067
0.061 1 0.065 0.062 1 0.067
%Oxygen 40.36 1 42.78 33.58 1 36.77 32.83 1 36.28 33.37
1 35.94 33.30 1 35.73 32.86 1 35.23
* "% Moisture" with respect to the "Torrefied Wood Pellets" on a "Wet
Basis" refers to
the amount of water (in %) in the sample following cooling in the water bath
for 5
minutes and then draining for 5 minutes, as described in the Methods.
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Table 9: Heat Value of Torrefied Wood Pellets Before and After Torrefusion at
260 C
Measurements Before Torrefusion Torrefusion Torrefusion Torrefusion
Torrefusion
Torrefusion for 10 mins. for 15 mins. for 20 mins.
for 25 mins. for 30 mins.
Wet I Thy Wet Dry Wet I Dry Wet ! Thy Wet I
Dry Wet ! Dry
Basis Basis Basis i Basis Basis Basis Basis i Basis Basis
Basis Basis i Basis
Weight 1 kg 1 kg 1 kg 1 kg 1 kg 1 kg
A) Moisture" 5.66 0 10.01 0 7.62 0 9.13 I 0
6.92 I 0 6.59 I 0
% Ash 0.42 1 044 0.39 044 0.39 1 0.42 0.37 1 0.41
0.39 1 042 0.4 1 043
A) Volatile 79.99 i 84.79 =
Matter 76.06 84.52 78.25 84.7 75.83 i 83.44 77.91
83.7 77.42 i 82.89
A) Sulphur 0.03 0.04 0.01 i 0.01 0.01 0.01 0.01 0.01
0.02 0.02 0.02 0.03
Calorific
Value (Gross)
Btu/lb 8309 8807 8989 9989 9475 10256 9376 10318 9677 10397 9771 10461
Kcal/kg 4616 i 4893 4994 i 5550 5264 5698 5209 5732 5376
5776 5428 5812
GJ/T 1933. 2049. 2091. 23.24 2204. 23.86 21.81 24 22.51 24.18 22.73
24.33
A) Carbon 47.76 50.62 50.81 56.47 52.5 56.83 51.92 57.14
53.42 57.39 53.87 57.68
% Nitrogen 0.068 0.073 0.068 0.075 0.064 0.069 0.063 0.070 0.069
0.074 0.058 0.062
%Oxygen 40.36 42.78 32.59 36.19 33.13 35.87 32.34 35.58 32.86 35.31 32.71
35.00
"% Moisture" with respect to the "Torrefied Wood Pellets" on a "Wet Basis"
refers to
the amount of water (in %) in the sample following cooling in the water bath
for 5
minutes and then draining for 5 minutes, as described in the Methods.
Table 10: Heat Value of Torrefied Wood Pellets Before and After Torrefusion at
265 C
Measurements Before Torrefusion Torrefusion Torrefusion Torrefusion
Torrefusion
Torrefusion for 10 mins. for 15 mins. for 20 mins.
for 25 mins. for 30 mins.
Wet Dry Wet ; Thy Wet Dry Wet ; Dry Wet ; Dry
Wet ; Dry
Basis : Basis Basis I Basis Basis : Basis Basis I Basis Basis I Basis Basis
I Basis
Weight 1 kg i 1 kg 1 kg 1 kg 1 kg 1 kg
A) Moisture" 5.66 I 0 8.35 I 0 9.44 I 0 7.53 0 7.06
0 6.76 0
A) Ash 0.42 0.44 0.38 0.41 0.39 0.43 0.37 0.4
0.38 0.41 0.4 0.43
A) Volatile 79.99 i 84.79 1 1 1
Matter 77.45 84.51 75.58 83.46 77.2 I 83.49
76.74 82.57 77.25 82.86
A) Sulphur 0.03 i 0.04 0.02 i 0.02 0.01 i 0.01 0.01 0.01
0.01 0.01 0.01 0.01
Calorific
Value (Gross)
Btu/lb 8309 8807 9341 10193 9326 10298 9759 10554 9763 10504 9823 10535
Kcal/kg 4616 4893 5190 5663 5181 5721 5422 5863 5424 5836 5457 5853
GJ/T 19.33 20.49 21.73 23.71 21.69 23.95 22.7 24.55 22.71 24.43 22.85
24.51
A) Carbon 47.76 50.62 51.67 56.38 51.66 57.05 53.85 58.24
53.87 57.96 54.33 58.27
A) Nitrogen 0.068 0.073 0.068 0.074 0.064 0.071 0.063
0.068 0.062 0.067 0.053 0.057
%Oxygen 40.36 42.78 33.35 36.39 32.34 35.71 31.88 34.46 32.31 34.76 32.10
34.42
"% Moisture" with respect to the "Torrefied Wood Pellets" on a "Wet Basis"
refers to
the amount of water (in %) in the sample following cooling in the water bath
for 5
minutes and then draining for 5 minutes, as described in the Methods.
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Table 11: Heat Value of Torrefied Wood Pellets Before and After Torrefusion at
270 C
Measurements Before Torrefusion Torrefusion Torrefusion Torrefusion
Torrefusion
Torrefusion for 10 mins. for 15 mins. for 20 mins.
for 25 mins. for 30 mins.
Wet I Dry Wet I Thy Wet I Dry Wet I Dry Wet I
Dry Wet I Dry
! . : !
Basis : Basis Basis Basis Basis Basis Basis : Basis Basis : Basis Basis
: Basis
Weight 1 kg : 1 kg : 1 kg : 1 kg : 1 kg 1 kg :
`)/0 Moisture* 5.66 i 0 9.36 i 0 10.12 i 0 8.26 1 0 7.28
0 7.2 I 0
% Ash 0.42 1 044 0.34 0.38 0.36 1 OA 0.41 1 044 0.38
0.41 0.38 1 041
`)/0 Volatile 79.99 i 84.79 1 =
Matter 1 76.4 1 84.3 75.3 1 83.77 75.32 1 82.11
77.14 1 83.2 76.3 i 82.23
`)/0 Fixed 13.93 I 14.77 I i i
!
Carbon 13.90 1 15.32 14.22 1 15.83 -- 1 --
15.20 1 16.39 16.12 ! 17.36
`)/0 Sulphur 0.03 1 0.04 0.03 1 0.03 0.03 1 0.03 0.01 1 0.01
0.03 0.03 0.03 1 0.03
Calorific
Value (Gross)
Btu/lb 8309 I 8807 9347 I 10313 9347 I
10399 9623 I 10490 9858 10631 9918 I 10688
Kcal/kg 4616 1 4893 5193 1 5729 5193 1 5777 5346 1 5828
5477 5906 5510 1 5938
GJ/T 19.33 2049. 21.74 23.99 21.74 24.19 22.38 244 22.93 24.73 23.07
24.86
`)/0 Carbon 47.76 1 50.62 51.74 1 57.08 51.82 1 57.65
53.39 ! 58.19 54.39 58.66 54.85 1 59.11
% Nitrogen 0.068 1 0.073 0.149 ! 0.164 0.139 1 0.155
0.068 1 0.074 0.134 0.145 0.134 ! 0.144
%Oxygen 40.36 1 42.78 32.31 1 35.66 31.47 1 35.03
31.64 1 34.51 31.50 33.98 31.09 1 33.50
* "% Moisture" with respect to the "Torrefied Wood Pellets" on a "Wet
Basis" refers to
the amount of water (in %) in the sample following cooling in the water bath
for 5
minutes and then draining for 5 minutes, as described in the Methods.
Table 12: Heat Value of Torrefied Wood Pellets Before and After Torrefusion at
280 C
Measurements Before Torrefusion Torrefusion for 30 mins.
Wet Basis I Dry Basis Wet Basis I Dry Basis
i i
Weight 1 kg 1 kg .
:
% Moisture* 5.66 1 0 9.05 1 0
% Ash 0.42
0.44 0.41 1 0.45
% Volatile Matter 79.99 1 84.79 73.75 1 81.09
% Fixed Carbon 13.93 1 14.77 16.79 1 18.46
% Sulphur 0.03 I 0.04 0.03 0.03
i
Calorific Value
(Gross) 1
Btu/lb 8309 1 8807 9913 10900
Kcal/kg 4616 1 4893 5507 6056
GJ/T 19.33 1 20.49 23.06 25.35
% Carbon 47.76 50.62 54.62 60.06
% Nitrogen 0.068 1 0.073 0.138 0.152
%Oxygen 40.36 1 42.78 29.60 32.54
* "% Moisture" with respect to the "Torrefied Wood Pellets" on a "Wet
Basis" refers to the amount of water (in %) in the sample following
cooling in the water bath for 5 minutes and then draining for 5 minutes,
as described in the Methods.
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Table 13: Heat Value of Torrefied Wood Pellets Before and After Torrefusion at
290 C
Measurements Before Torrefusion Torrefusion for 30 mins.
Wet Basis I Dry Basis Wet Basis I Dry Basis
Weight 1 kg 1 kg
% Moisture* 5.66 0 10.03 0
% Ash 0.42 0.44 0.43 0.47
% Volatile Matter 79.99 84.79 71.15 79.08
% Fixed Carbon 13.93 14.77 18.39 20.45
% Sulphur 0.03 I 0.04 0.03 I 0.03
Calorific Value
(Gross)
Btu/lb 8309 8807 10071 11194
Kcal/kg 4616 4893 5595 6219
GJ/T 19.33 20.49 23.42 26.04
% Carbon 47.76 50.62 55.91 62.15
% Nitrogen 0.068 0.073 0.143 0.159
%Oxygen 40.36 42.78 27.31 30.35
"% Moisture" with respect to the "Torrefied Wood Pellets" on a "Wet
Basis" refers to the amount of water (in %) in the sample following
cooling in the water bath for 5 minutes and then draining for 5 minutes,
as described in the Methods.
Example 7:
Materials and Methods
The same method as described in Example 6 was used in this example, including
the
different submersion times in the heated canola oil (i.e., either 10, 15, 20,
25 or 30 minutes)
and the different temperatures of the canola oil used in the process (i.e.,
either 240, 245, 250,
255, 250, 265 or 270 C; and submersing for 30 minutes at 280 C or 290 C).
In this example, the resulting data was analyzed to determine the carbon
content of
the torrefied pellets after each temperature-time combination.
Results
The data for this Example 7 are shown in Tables 5-13 above and in Figure 10.
The
results indicated that the carbon percentage of the torrefied wood pellets at
the end of the
torrefaction process generally increased with an increase in
submersion/retention time in
heated canola oil and with an increase in the temperature of the heated oil.
As shown in
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Figure 10, there was a general upward trend in the carbon content of the
torrefied wood
pellets with an increase in temperature of the canola oil. There was also
substantial
correlation between carbon content and submersion time in heated oil.
The highest carbon content was obtained when the densified wood pellets were
5 submersed in 290 C canola oil for 30 minutes (62.15 carbon % on a bone
dry basis) and the
lowest carbon content was obtained when the densified wood pellets were
submersed in
240 C canola oil for 10 minutes (54.80 carbon % on a bone dry basis). The
carbon content for
all torrefied pellets was greater than the carbon percentage calculated for
densified biomass
that was not torrefied (i.e., 50.62 carbon % on a bone dry basis).
10 Example 8:
Materials and Methods
The amount of evaporation of the different types of combustible liquids were
tested.
Each combustible liquid was tested once using the following evaporation test.
The small test
unit as described above for Example 1 was used for this test. The small
container was placed
15 on the scale and the net weight of the empty small container was
measured. A volume of oil
was measured out and poured into the small container and a lid placed on top
of the small
container. The gas burner was then turned on to 270 C, and the temperature of
the oil was
monitored. Once the desired temperature of 270 C was reached, the small
container with the
vegetable oil was removed from the gas burner and the small container with the
vegetable oil
20 was calculated. The small container with the vegetable oil was then put
back on the gas
burner and allowed to heat for 30 minutes at 270 C. The weight of the small
container with
the vegetable oil was measured after 30 minutes of heating and the reduction
in weight
caused by evaporation recorded.
The different combustible liquids tested were: canola oil, sunflower oil, corn
oil,
25 peanut oil, bar and chain oil, 5W30 oil, automatic transmission fluid,
hydraulic fluid AW32,
gear oil 80W90, and paraffin wax.
Results
The results indicated that evaporation of each of the different combustible
liquids
after heating at 270 C for 30 minutes was negligible. Accordingly, evaporation
of the
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combustible liquids was not taken into account when calculating oil absorption
by torrefied
densifed biomass following a torrefaction process.
Example 9:
Materials and Methods
This Example 9 was performed in order to compare the oil absorption by
densified
pellets when using canola oil as the combustible liquid versus paraffin wax as
the
combustible liquid.
In this example, densified softwood pellets made from a blend of spruce, pine
and fir
(SPF wood pellets) were tested. A 250 gram sample of SPF wood pellets was
weighed out
and a wire sieve for holding the densified material was separately weighed.
The sample of
densified material was then loaded into the wire sieve and the total weight of
the sieve plus
densified material was measured and then set aside for testing purposes. The
small test unit
described in Example 1 was used for this example. As an initial step, the
small container was
placed on a scale and the net weight of the small container was measured. A
volume of oil
(either canola oil or paraffin wax) was measured out and poured into the small
container and
the total weight of the small container plus oil was measured, thereby
providing a net weight
for the oil.
Once the measurements of the oil were complete, the gas burner was turned on
to a
specific temperature (either 250 C, 260 C or 270 C), and the temperature of
the oil was
monitored.
After the temperature of the oil was stabilized at the desired temperature,
the
following weights were measured: (a) the weight of the small container plus
the heated oil;
(b) the weight of the small container plus the heated oil plus the lid for the
small container
plus a temperature probe inserted into the small container; and (c) the weight
of the small
container plus the heated oil plus the lid for the small container plus a
temperature probe
inserted into the small container plus the 250 gram sample of densified
material loaded in the
wire sieve and placed on top of the small container (i.e., not yet submerged
in the small
container).
Upon completion of the above measurements, the wire sieve containing the
densified
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material was submerged in the heated oil and the small container covered with
a lid. The
densified material was submerged in the heated oil for a specific amount of
time (either 15 or
30 minutes). After submersion for the desired time, the gas burner was turned
off and the
total weight of the small container, oil, lid, temperature probe, sieve and
densified material
was measured (with the sieve and densified material still submerged in the
oil). The wire
sieve with the densified material contained therein was then removed from the
small
container and oil, and allowed to drain over the small container for about
five minutes. The
drained wire sieve with the densified material contained therein was weighed,
and the
densified material was subsequently weighed separately. With the sieve and
densified
material removed, the total weight of the small container, oil, lid and
temperature probe was
weighed and then the total weight of the small container plus oil was
subsequently weighed
separately.
The bone dry weight of the torrefied pellets was then calculated (i.e., to
provide a
bone dry basis for the torrefied pellets), and then the bone dry weight of the
pellets was
compared to the loss of oil and a % oil absorption calculated.
The above process was completed twice for each temperature, time and oil
combination (i.e., two test runs done for each different type of oil being
tested at each
different temperature and submersion time), with each process starting with a
250 gram
sample of densified pellets.
Results
As shown in Figure 11, when canola oil was used as the combustible liquid for
the
torrefaction process, oil absorption by the densified biomass tended to
generally increase
when the temperature of the canola oil was increased from 250 C to 260 C, but
then declined
slightly when torrefied at a temperature of 270 C. There also appeared to be a
general
decrease in weight of the torrefied densified biomass with increased
temperature; however,
carrying out the torrefaction process at 260 C for 30 minutes caused an
increase in weight
(i.e., +11.48g compared to starting weight, which amounted to a weight of
249.35g) as
compared to carrying out the process at 250 C for 30 minutes (+8.53g compared
to starting
weight, which amounted to an end weight of 246.4g). This increase in weight
corresponded
with an increase in oil absorption for this temperature-time condition (i.e.,
an oil absorption
of 21.02% per mass input of bone dry pellets at 260 C for 30 minutes, as
compared to an oil
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absorption of 16.65% at 250 C for 30 minutes), which suggested that the weight
increase is
due to the increased oil absorption when torrefying at 260 C for 30 minutes.
The slight
decline in oil absorption when a temperature of 270 C was used (i.e., 16.86%
oil absorption
at 15 minutes and 17.11% at 30 minutes) also corresponded to a decrease in the
weight of the
torrefied densified biomass at this temperature (i.e., -1.28g at 15 minutes
and -5.47g at 30
minutes), further suggesting that oil absorption is correlated with the weight
of the resulting
torrefied densified biomass. This data also correlated with the data obtained
from Examples 3
and 5.
Figure 12 shows that similar results were obtained when paraffin wax was used
as the
to combustible liquid. Oil absorption by the densified biomass tended to
generally increase
when the temperature of the paraffin wax was increased from 250 C to 260 C,
but then
declined when torrefied at a temperature of 270 C. The rate of increase in the
oil absorption
was greater for paraffin wax than for canola oil when increasing the
temperature from 250 C
to 260 C and when increasing the submersion time at each temperature point. As
with canola
oil, there also appeared to be a general decrease in weight of the torrefied
densified biomass
with increased temperature. However, there did not seem to be a correlation
between the
weight of the torrefied densified biomass at the end of the process and the
oil absorbed by the
torrefied densified biomass as seen with canola oil.
Figure 13 and Tables 14 and 15 below illustrate that generally more canola oil
was
lost during the torrefaction process when canola oil was used as the
combustible liquid. The
amount of oil loss was generally similar when using either canola oil or
paraffin wax, except
when torrefying at 250 C. The amount of paraffin wax lost when torrefying at
250 C for 15
minutes was significantly less with paraffin wax. Furthermore, the rate of
loss of oil between
15 minutes of torrefaction and 30 minutes of torrefaction at 250 C when
paraffin wax was
used as the combustible liquid seemed to be significantly greater than when
canola oil was
used.
As shown in Figure 14, when using canola oil as the combustible liquid rather
than
paraffin wax, the reduction in weight of the torrefied pellet as compared to
the starting
biomass differed. For both, as shown in Tables 14 and 15 and described above,
the weight of
the torrefied pellets generally tended to decrease with increased temperature.
However, with
canola oil, the weight of the torrefied pellets was greater than the starting
densified pellets
when the torrefaction process was carried out at 250 C and 260 C. There was
only a
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54
reduction in weight as compared to the starting densified pellets when
torrefying at 270 C.
With paraffin wax, the end weight of the torrefied pellet was generally less
than the starting
weight of the densified pellet, except when torrefying at 250 C for 15
minutes. Paraffin wax
generally led to a greater reduction in weight at all time points and
temperatures. Without
wishing to be bound by theory, these results may be due to the biomass
absorbing less
paraffin wax during the torrefaction process than when canola oil is used.
Less absorption of
the paraffin wax may be as a result of the longer molecular chain of paraffin
wax and perhaps
a greater evaporation rate of paraffin wax.
Table 14: Canola Oil Absorption by Pellets and Weight Reduction of Pellets
During
Torrefaction at Different Temperatures and Submersion Times
Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6
Submersion Time (mins.) 15 30 15 30 15 30
Temperature (SC) 250 250 260 260 _ 270 270
Sample Weight - at start;
250.00 250.00 250.00 250.00 I 250.00
250.00
wet basis (g)
Moisture Content (%)* 4.85 4.85 4.85 4.85 4.85 4.85
Sample Weight - at start;
237.88 237.88 237.88 237.88 237.88
237.88
bone dry basis (g)
Sample Weight-at end;
251.30 246.40 244.48 249.35 236.60
232.40
bone dry basis (g)
Change in Weight - bone dry
+13.43 +8.53 +6.60 +11.48 -1.28 -5.47
basis (g)
Pot + Oil Weight - at start
2,390.20 2,350.75 2,355.40 2,359.20 1
2,352.90 2,346.70
(g)
Pot + Oil Weight - at end (g) 2,356.20 2,311.15 2,318.10 2,309.20
2,312.80 2,306.00
Change in Pot + Oil Weight
-34.00 -39.60 -37.30 -50.00 I -40.10
-40.70
(g)
Reduction in Pellet Weight
5.64 3.58 2.78 4.82 -0.54 -2.30
Start to Finish (/o)
% Oil Absorption by Sample
Including Evaporation (bone 14.29% 16.65% 15.68% 21.02% 16.86%
17.11%
dry basis)
"Moisture Content" refers to the amount of water in the samples immediately
after the
torrefaction process (i.e., after drip drying for 5 minutes).
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Table 15: Paraffin Wax Absorption by Pellets and Weight Reduction of Pellets
During
Torrefaction at Different Temperatures and Submersion Times
Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6
Submersion Time (mins.) 15 30 15 30 15 30
Temperature (SC) 250 250 260 260 270 270
Sample Weight - at start;
250.00 250.00 250.00 250.00 250.00
250.00
wet basis (g)
4.85
1 4.85 1 4.85
Moisture Content (%)* 4.85 ; 4.85 1 4.85
Sample Weight - at start;
237.88 237.88 237.88 237.88 237.88
237.88
bone dry basis (g)
Sample Weight-at end;
242.60 234.95 231.40 230.75 I 219.15
210.95
bone dry basis (g)
Change in Weight - bone dry
+4.72 -2.93 -6.47 -7.13 -18.73 -26.93
basis (g)
Pot + Oil Weight-at start 2,185.10 2,222.35 2,183.30 2,212.05
2,252.75 2,214.60
(g) 1
Pot + Oil Weight - at end (g) 2,178.60 1 2,186.40 2,151.30 !
2,162.85 2,219.20 ! 2,176.45
Change in Pot + Oil Weight 6.50 35.95 32.00 49.20 33.55
38.15
(g)
Reduction in Pellet Weight 1.99 ! -1.23 -2.72 -3.00 -7.87
I -11.32
Start to Finish (%)
% Oil Absorption by Sample 3 ! 15 13 21 ! 14 ! 16
Including Evaporation (bone
dry basis)
"Moisture Content" refers to the amount of water in the samples immediately
after the
torrefaction process (i.e., after drip drying for 5 minutes).
5 Example 10:
Materials and Methods
The torrefied pellets from Example 6, which proceeded through the torrefaction
process at different temperatures (240 C, 245 C, 250 C, 255 C, 260 C, 265 C,
270 C,
280 C or 290 C) for different submersion times (10, 15, 20, 25 or 30 minutes),
were tested to
10 determine the hydrophobic nature of the torrefied pellets. To do this, a
953.63 gram sample
from each batch of processed torrefied densified biomass corresponding to a
specific
temperature-time condition was measured out and submersed in water for two
weeks (i.e., 14
days). Once removed from the water, the samples were allowed to drain in a
sieve for 5
minutes, and then each sample was weighed to measure the change in weight of
the sample.
15 This measurement was compared to the weight of the water, and the amount
of water
absorbed by each sample was calculated.
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Results
The data in Table 16 indicated that as the temperature of the torrefaction
process
increased (i.e., the temperature of the heated canola oil), the hydrophobic
nature of the
resulting product increased. This data is represented in Figures 15 and 16,
which show that
the amount of water absorbed by the torrefied densified pellets following the
torrefaction
process correlated with the temperature of the torrefaction process. When
torrefied at higher
temperatures (such as 270 C, 280 C or 290 C) rather than at lower temperatures
(such as
240 C), the resulting torrefied densified pellets absorbed less water into the
pellets.
The submersion time in the heated canola oil appeared to be less material to
the
hydrophobic nature of the resulting product; however, the results indicated
that generally for
shorter submersion times (e.g., 10 minutes), more water was absorbed by the
resulting
torrefied densified pellets compared to when longer submersion times were used
for the
torrefaction process (e.g., 30 minutes).
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Table 16: Water Absorption Following Torrefaction
-
'
Sample Torrefaction i Process i Gross i Weight of i Net
i Torrefied i Water
temperature i time i Weight of i Container i Weight of i Sample i
Absorbed
( C) 1 (minutes) 1 Water (g) 1 (g) 1 Water (g) 1 Weight (g) I
(g)
1 240 10 1,536.50 46.37 1490.13 953.63 536.50
2 240 i 15 ! 1,437.20 I 46.37 I 1390.83 1
953.63 i 437.20
3 240 ! 20 I 1,397.50 I 46.37 I 1351.13 !
953.63 I 397.50
4 240 25 1,391.50 46.37 1345.13 953.63 391.50
240 . 30 . 1,394.00 . 46.37 . 1347.63 . 953.63
. 394.00
6 245 . 10 1,448.35 46.37 1401.98 953.63 448.35
, ,
7 245 i 15 i 1,377.20 i 46.37 i 1330.83 i
953.63 i 377.20
! i !
8 245
20 i 1,377.85 46.37
1331.48 953.63 377.85
9 245 25 1,336.45 46.37 1290.08 953.63 336.45
245 30 1,335.70 46.37 1289.33 953.63 335.70
11 250 10 1,421.80 46.37 1375.43 953.63 421.80
12 250 , 15 1,337.90 46.37 1291.53 953.63 337.90
! !
13 250 ! 20 ; 1,305.20 ; 46.37 ; 1258.83 I
953.63 I 305.20
14 250 25 1,319.70 46.37 1273.33 953.63 319.70
250 30 1,285.55 46.37 1239.18 953.63 285.55
16 255 10 1358.10 46.37 1311.73 953.63 358.10
17 255 . 15 1286.25 46.37 1239.88 953.63 286.25
: ! :
18 255 i 20 i 1291.85 i 46.37 i 1245.48 i
953.63 i 291.85
19 255 25 1260.05 46.37 1213.68 953.63 260.05
255 30 1243.35 46.37 1196.98 953.63 243.35
21 260 10 1294.50 46.37 1248.13 953.63 294.50
22 260 15 1290.30 46.37 1243.93 953.63 290.30
23 260 : 20 : 1232.85 : 46.37 : 1186.48 :
953.63 : 232.85
24 260 25 1227.95 46.37 1181.58 953.63 227.95
260 30 1223.95 46.37 1177.58 953.63 223.95
26 265 10 1281.10 46.37 1234.73 953.63 281.10
27 265 15 1224.85 46.37 1178.48 953.63 224.85
;
28 265 i 20 : 1225.40 i 46.37
1 1179.03 i 953.63 i 225.40
1
29 265 25 i 1208.25 i 46.37 i 1161.88 !
953.63 i 208.25
265 30 1207.40 46.37 1161.03 953.63 207.40
31 270 10 1236.80 46.37 1190.43 953.63 236.80
32 270 15 1184.40 46.37 1138.03 953.63 184.40
33 270 i 20 i 1192.30 i 46.37 i 1145.93 i
953.63 i 192.30
I I i
34 270 i 25 1 1164.10 1 46.37 1 1117.73 1
953.63 1 164.10
270 30 1167.80 46.37 1121.43 953.63 167.80
36 280 30 1161.60 46.37 1115.23 953.63 161.60
37 290 30 1149.90 46.37 1103.53 953.63 149.90
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Example 11:
Materials and Methods
In this example, both densified softwood pellets made from a blend of spruce,
pine
and fir (SPF wood pellets) and densified hog fuel were tested. A 250 gram
sample of either
SPF wood pellets or densified hog fuel was weighed out and a wire sieve for
holding the
densified material was separately weighed. The sample of densified material
was then loaded
into the wire sieve and the total weight of the sieve plus densified material
was measured and
then set aside for testing purposes using the small test unit described in
Example 1.
As an initial step, the small container was placed on a scale and the net
weight of the
empty small container was measured. A volume of oil (one of the following:
sunflower oil,
corn oil, peanut oil, canola oil, bar and chain oil, 5W30 oil, automatic
transmission fluid,
hydraulic fluid AW32, gear oil 80W90, or paraffin wax) was measured out and
poured into
the small container and the total weight of the small container plus oil was
measured, thereby
providing a net weight for the oil.
Once the measurements of the oil were complete, the gas burner was turned on
to the
testing temperature of 270 C, and the temperature of the oil was monitored.
After the temperature of the oil was stabilized at 270 C, the following
weights were
measured: (a) the weight of the small container plus the heated oil; (b) the
weight of the small
container plus the heated oil plus the lid for the small container plus a
temperature probe
inserted into the small container; and (c) the weight of the small container
plus the heated oil
plus the lid for the small container plus a temperature probe inserted into
the small container
plus the 250 gram sample of densified material loaded in the wire sieve and
placed on top of
the small container (i.e., not yet submerged in the small container).
Upon completion of the above measurements, the wire sieve containing the
densified
material was submerged in the heated oil and the small container covered with
a lid. The
densified material was submerged in the heated oil for 30 minutes. After the
30 minute
submersion time, the small container was turned off and the total weight of
the small
container, oil, lid, temperature probe, sieve and densified material was
measured (with the
sieve and densified material still submerged in the oil). The wire sieve with
the densified
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material contained therein was then removed from the small container and oil,
and allowed to
drain over the small container for 5 minutes, except in the case of hog fuel,
which was
allowed to drain for 10 minutes. The drained wire sieve with the densified
material contained
therein was weighed, and the densified material was subsequently weighed
separately. With
the sieve and densified material removed, the total weight of the small
container, oil, lid and
temperature probe was weighed and then the total weight of the small container
plus oil was
subsequently weighed separately.
The bone dry weight of the torrefied pellets was then calculated, and then the
bone
dry weight of the pellets was compared to the loss of oil (net of evaporation
of the oil) and
calculated as a percentage loss of canola oil.
The above process was done twice for each different type of oil used (i.e.,
two test
runs done for each different type of oil being tested), with each process
starting with a 250
gram sample of densified pellets.
Results
The data from this example are shown in Table 17 and Figure 17 for the plant-
derived
oils, and in Table 18 and Figure 18 for the petroleum-based oils. These
results indicated that
torrefaction of the densified biomass in the plant-derived oils generally
tended to result in less
oil absorption by the resulting torrefied densified biomass, when compared to
torrefaction of
the densified biomass in the petroleum-based oils.
Amongst the plant-derived oils, torrefaction of SPF pellets in sunflower oil
at 270 C
for 30 minutes resulted in the least amount of oil being absorbed by the
densified biomass (on
average about 11.38% oil absorption). Canola oil resulted in the most oil
absorption by the
torrefied densified biomass after torrefaction in canola oil at 270 C for 30
minutes (on
average about 12.12% oil absorption).
Amongst the petroleum-based oils, paraffin wax followed by 5W30 motor oil
resulted
in the least amount of oil absorption by the torrefied densified biomass (on
average about
16.48% and 17.10% oil absorption, respectively). Gear oil (80W90) resulted in
the most oil
absorption by the torrefied densified biomass after torrefaction in the gear
oil at 270 C for 30
minutes (on average about 24.32% oil absorption).
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The data in Tables 17 and 18 also indicated that torrefaction in plant-derived
oils
resulted in a generally lower average net loss in weight of the biomass as
compared to
torrefaction in petroleum-based oils. Amongst the plant-derived oils,
torrefaction in peanut
oil resulted in the lowest average net loss in weight (i.e., a net loss in
weight of about 7.70 g)
5 and torrefaction in sunflower oil resulted in the highest average net
loss in weight (i.e., a net
loss in weight of about 10.85 g). Amongst the petroleum-based oils,
torrefaction in bar and
chain oil and hydraulic fluid (AW32) resulted in the lowest average net losses
in weight (i.e.,
net losses in weight of about 10.70 g and 10.60 g, respectively) and
torrefaction in automatic
transmission fluid (ATF) resulted in the highest average net loss in weight
(i.e., a net loss in
10 weight of about 17.23 g).
As shown in Tables 17 and 18, when hog fuel was used as the starting densified
biomass, significantly greater oil absorption occurred by the hog fuel biomass
in plant-
derived oils (canola oil) and petroleum-based oils (paraffin wax) and a
significantly greater
average net loss in weight occurred when the hog fuel biomass was torrefied in
plant-derived
15 oils (canola oil) and petroleum-based oils (paraffin wax).
Table 17: Oil Absorption and Net Loss of Mass for Different Plant-derived Oils
Sample Combustible Densified Oil Net Loss
Average Oil Average Net
Liquid Biomass Absorption in Weight
Absorption Loss in
(%) (g) (%) Weight (g)
1 Sunflower oil SPF pellets 10.81 12.25
11.38
10.85
2 Sunflower oil SPF pellets 11.96 9.45
1 Corn oil SPF pellets 11.25 9.15
11.88 9.33
2 Corn oil SPF pellets 12.52 9.50
1 Peanut oil I SPF pellets I 12.02 7.35 I
11.76 7.70
2 Peanut oil SPF pellets 11.50 8.05
1 Canola oil SPF pellets 10.93 12.05
12.12 - 10.58
2 Canola oil SPF pellets 13.30 9.10
1 Canola oil Hog fuel 213.40 74.00
2 Canola oil Hog fuel 265.13 102.45 239.27 88.23
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Table 18: Oil Absorption and Net Loss of Mass for Different Petroleum-Based
Oils
Sample 1 Combustible 1 Densified 1 Oil 1 Net Loss in 1 Average Oil 1
Average Net
Liquid Biomass Absorption Weight
Absorption Loss in
(%) (g) (%)
Weight (g)
1 Bar and Chain oil SPF pellets 19.71 11.00
20.39 10.70
2 _ Bar and Chain oil _ SPF pellets _ 21.07 _ 10.40 _
1 5W30 motor oil SPF pellets 19.18 14.25
17.10 13.25
2 5W30 motor oil _ SPF pellets _ 15.02 _ 12.25
_
Automatic
1SPF pellets 22.70 18.20
transmission fluid
- 20.90 -
17.23
i Automatic
2SPF pellets 19.10 16.25
i transmission fluid 1
Hydraulic fluid
1 (AW32) SPF pellets 25.72 9.05
19.99 10.60
Hydraulic fluid
2 SPF pellets 14.26 12.15
(AW32)
1 Gear oil (80W90) SPF pellets 34.09 13.70
- 24.32 12.93
2 Gear oil (80W90) SPF pellets 14.55 14.75
1 i Paraffin wax SPF pellets i 15.35 i 14.50
- 16.48 14.48
2 Paraffin wax SPF pellets 17.61 14.45
1 Paraffin wax i Hog fuel 230.89 73.15 i =
231.00 65.80
2 Paraffin wax Hog fuel 231.10 58.45
Example 12:
Materials and Methods
In this example, 2 kilograms of densified softwood pellets made from a blend
of
spruce, pine and fir (SPF wood pellets) were tested. The 2 kilograms were
divided into 1
kilogram samples, and each 1 kilogram sample was tested using the method as
described
above in Example 1 in a combustible liquid (either a plant-derived oil or a
petroleum-based
oil) heated to a temperature of 270 C for 30 minutes. The method was repeated
for the 2 1-kg
samples for each different type of oil. Accordingly, for each type of oil, the
method was
to repeated twice with a 1-kg sample each time. The resulting torrefied
densified biomass from
both test experiments for each type of oil were collected and mixed together
to form a sample
batch. One kilogram of the sample batch was collected for testing.
In this example, the resulting 1-kg sample batch was analyzed to determine the
heat
energy values of the torrefied pellets after each temperature-time condition.
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The plant-derived oils used in this example included peanut oil, sunflower oil
and
corn oil. The petroleum-based oils used in this example included automatic
transmission
fluid, gear oil 80W90, motor oil (5W30), bar and chain oil, and hydraulic
fluid AW32.
Results
The results shown in Tables 19 and 20 below indicated that the petroleum-based
oils
generally tended to result in torrefied densified biomass having slightly
higher heat energy
values than the densified biomass that was torrefied in plant-derived oils.
For example, the
heat energy values for torrefied densified biomass processed in petroleum-
based oils were
approximately 26 gigajoules per metric tonne (W/t); whereas the heat energy
values for
biomass processed in plant-derived oils were approximately about 24-25 GJ/t.
This difference
may be due to greater oil absorption by petroleum-processed biomass, as shown
in Example
10 above.
The results further indicated that all of the plant-derived oils produced
torrefied products with
approximately similar heat energy values, and all of the petroleum-based oils
similarly
produced torrefied products with approximately similar heat energy values.
Table 19: Heat Value of Torrefied Wood Pellets After Torrefusion at 270 C for
30
Minutes in Plant-derived Oils
Measurements Sunflower oil Corn Oil Peanut Oil
Wet Dry Wet I Dry Wet Dry
Basis I Basis Basis Basis Basis I Basis
Weight 1 kg 1 kg 1 kg
% Moisture* 1.04 0 0.78 0 1.52 0
% Ash 0.47 0.48 0.44 0.44 0.43 0.44
% Volatile Matter 80.96 81.81 80.69 81.32 80.22 81.46
% Fixed Carbon 17.53 17.71 18.09 18.24 17.83 18.10
% Sulphur 0.02 0.02 0.02 I 0.02 0.02 0.02
Calorific Value
(Gross) ;
=
;
=
;
Btu/lb 10615 10727 10616 10699 10426 10587
Kcal/kg 5897 5959 5898 5944 5792 5881
GJ/T 24.69 24.95 24.69 24.89 24.25 24.62
% Carbon 58.27 58.88 58.63 j 59.09 57.72 j 58.61
% Nitrogen 0.15 0.15 0.14 0.14 0.13 0.13
%Oxygen 33.34 33.69 33.29 I 33.56 33.53 I 34.04
"% Moisture" refers to the amount of water in the samples immediately after
the
torrefaction process (i.e., after drip drying for 5 minutes).
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Table 20: Heat Value of Torrefied Wood Pellets After Torrefusion at 270 C for
30
Minutes in Petroleum-Based Oils
Measurements Bar & Chain AW32 Automatic Gear Oil Motor Oil
Oil Hydraulic Oil Transmission 80W90 5W30
Fluid
Wet Dry Wet Dry Wet Dry Wet Dry Wet Dry
Basis Basis Basis Basis Basis Basis Basis Basis Basis Basis
Weight 1 kg 1 kg 1 kg 1 kg 1 kg
% Moisture* 0.72 I 0 0.94 0 1.32 ! 0 0.71 I 0
0.81 0
% Ash 0.44 0.45 0.57 0.57 0.50 i 0.51 0.72 0.73
0.68 0.68
% Volatile 80.00 80.58
Matter 80.14 80.90 79.98 81.06 77.67 78.23 79.32 79.97
% Fixed 18.84 18.97
Carbon 18.35 18.53 18.20 18.43 20.90 21.04 19.19 19.35
% Sulphur 0.03 0.03 0.08 0.08 0.04 0.04 0.13 0.13
0.04 0.04
Calorific
Value (Gross)
Btu/lb 10983 11062 11088 11194 10951 11098 11318 11399 10892 10981
Kcal/kg 6102 6146 6160 6219 6084 j 6166 6288 6333
6051 6100
GJ/T 25.55 25.73 25.79 26.04 25.47 I 25.81 26.33
26.51 25.33 25.54
% Carbon 59.57 60.00 60.01 60.58 59.50 I 60.30 60.64 61.07
59.18 59.66
% Nitrogen 0.15 0.15 0.13 0.13 0.16 0.16 0.16 0.16
0.16 0.16
%Oxygen 32.19 32.42 31.27 31.57 31.59 32.01 30.72 30.94 32.30 32.58
"% Moisture" refers to the amount of water in the samples immediately after
the
torrefaction process (i.e., after drip drying for 5 minutes).
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Example 13:
Materials and Methods
A small scale torrefusion reactor was constructed in order to test the
continuous/semi-
continuous process disclosed herein. The reactor consists of a conveyor belt
that can
continuously or semi-continuously convey pellets through combustible liquid
held in a large
metal tank. The combustible liquid was heated with a temperature control. The
pellets were
delivered onto the conveyor belt of the reactor, where a hopper would be
located, and then
conveyed along the conveyor belt into, through and then out of the combustible
liquid. The
reactor is shown in Figure 19.
Results
The reactor shown in Figure 19 was used to torrefy wood pellets and
demonstrated
that a continuous/semi-continuous process could be used to torrefy pellets.
Densified pellets
were delivered onto the conveyor belt in hot combustible liquid (on the right-
hand side of
Figure 19) and conveyed through the combustible liquid and out the other end
(i.e., on the
left-hand side of Figure 19). The pellets were fully submersed as they
conveyed along the
conveyor belt through the combustible liquid and were delivered on the other
end as a
torrefied densified biomass.
