Note: Descriptions are shown in the official language in which they were submitted.
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METHOD & APPARATUS FOR PRODUCING BIOCHAR
FIELD
[0001] The
present disclosure provides a system and method for producing biochar from
biomass. In particular, the present disclosure provides pyrolytic systems and
methods of
producing biochar.
BACKGROUND
[0002] There
is an increasing interest in fuel derived from biomass such as forestry,
agricultural products or waste. There are various technologies for converting
biomass to fuel
such as direct burning, co-firing, gasification, fermentation, pyrolysis, and
the like.
Depending on the feedstock and the process used the resultant product will
have different
utilities and properties. In many cases, it is desired to produce a product to
replace a fossil
fuel leading to sustainability and environmental benefits.
[0003]
Pyrolysis is a type of thermal decomposition in which a substance is heated in
the
absence of oxygen, or under limited oxygen conditions. Pyrolysis may be termed
'fast' or
'slow' depending on the heating rate and residence time of the biomass. In the
case of dried
biomass, the pyrolysis can result in decomposition into three major products:
bio-char (also
known as biochar or biocoal), bio-oil, and syn-gas. The development of
efficacious
technology that enables the pyrolytic conversion of lower-value biomass into
higher energy
bio-fuels and products (bio-char/bio-coal and bio-oil) is desirable. In
particular, it is of
interest to provide technology for the production, optimization, and delivery
of bio-fuels,
particularly biochar, to be used in various agricultural, forestry, and
industrial applications
that can benefit from using renewable fuel sources
[0004]
Pyrolysis for the conversion of biomass into fuel products are described, for
example, in CA 2,242,279 which discloses an apparatus for continuous charcoal
production;
which CA 2,539,012 discloses a closed retort charcoal reactor system; CA
2,629,417 which
discloses systems and methods for the continuous production of charcoal by
pyrolysis of
organic feed.
[0005]
Although pyrolysis systems are known, to date they have met with limited
commercial success. Several factors can affect the utility of such systems
including the
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availability, moisture content and cost to transport the feedstock. As well as
the efficiency,
robustness and flexibility of the system.
[0006] It would be advantageous to have a relatively inexpensive,
transportable and/or
modular pyrolysis system for producing biochar. The system may be simple,
robust and/or
flexible enough to handle a variety of locations, feedstocks and conditions.
SUMMARY
[0007] The disclosure provides, at least in part, a system for producing
biochar from
biomass. The present systems may be modular comprising, for example, a reactor
module and
a syn-gas management module.
[0008] As used herein, the term 'biomass' refers to material derived from
non-fossilized
organic material, including plant matter such as lignocellulosic material and
animal material
such as wastes, suitable for conversion into biofuels.
[0009] As used herein, the term 'pyrolysis' refers to thermal decomposition
in which a
substance is heated in the absence of substantial amounts of oxygen.
[0010] As used herein, the term 'biochar' or `biocoal' refers to pyrolyzed
biomass.
Generally bio-char will have a calorific value of about 15 MJ/Kg or greater,
such as about 17
MJ/Kg or greater, or about 19 MJ/Kg or greater, about 21 MJ/Kg or greater,
about 23 MJ/Kg
or greater, about 25 MJ/Kg or greater, about 27 MJ/Kg or greater, about 29
MJ/Kg or greater.
[0011] As used herein, "a" or "an" means "one or more".
[0012] This summary does not necessarily describe all features of the
invention. Other
aspects, features and advantages of the invention will be apparent to those of
ordinary skill in
the art upon review of the following description of specific embodiments of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In the accompanying drawings, which illustrate one or more exemplary
non-
limiting embodiments:
[0014] Figure 1 shows a general flow diagram of an exemplary biomass
pyrolysis system
according to the present disclosure;
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[0015] Figure 2 shows a schematic of a biomass pyrolysis system;
[0016] Figure 3 shows the phases of biomass decomposition due to increasing
temperature (a) and a typical mass loss profile of biomass undergoing
pyrolysis (b).
DETAILED DESCRIPTION
[0017] The present disclosure provides, at least in part, a system for
pyrolysis of biomass,
the system comprising:
(a) a reactor having a retort extending therethrough, said retort comprising a
suitable conveyor such as, for example, an auger or paddle conveyor, an inlet,
and an outlet; the reactor further comprising at least one thermosensor, the
thermosensor capable of generating a signal when the temperature is above
optimal levels;
(b) a heating system adapted to heat the reactor;
(c) a syn-gas management system; the management system comprising a syn-gas
storage tank having an inlet and an outlet, said inlet in fluid communication
with the reactor, and said outlet in fluid communication with the heating
system and a syn-gas outlet such as a flare or storage tank wherein the
communication is controlled via a valve configurable between at least a first
position where flow is directed to the heating system and a second position
where flow is directed to the syn-gas outlet; and
(d) a controller in communication with the thermosensor and the valve;
wherein the controller switches the valve from the first position to the
second position
upon receiving a signal from the thermosensor that the temperature in the
reactor is
above optimal levels.
[0018] The present disclosure provides, at least in part, a system for
pyrolysis of biomass,
the system comprising:
(a) a reactor having a retort extending therethrough, said retort comprising a
suitable conveyor such as, for example, an auger or paddle conveyor, an inlet,
and an outlet; the reactor further comprising at least one thermosensor, the
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thermosensor capable of generating a signal when the temperature is below
optimal levels;
(b) a heating system adapted to heat the reactor;
(c) a syn-gas management system; the management system comprising a syn-gas
storage tank having an inlet and an outlet, said inlet in fluid communication
with the reactor, and said outlet in fluid communication with the heating
system and a syn-gas outlet such as a flare or storage tank wherein the
communication is controlled via a valve configurable between at least a first
position where flow is directed to the heating system and a second position
where flow is directed to the syn-gas outlet; and
(d) a controller in communication with the thermosensor and the valve;
wherein the controller switches the valve from the second position to the
first position
upon receiving a signal from the thermosensor that the temperature in the
reactor is
below optimal levels.
[0019] The
present thermosensor may be capable of generating a signal when the
temperature is above and below optimal levels. The temperature value at above
or below
which the thermosensor generates a signal may be predetermined. Such value may
be altered
depending on a variety of factors such as the needs of a particular production
run, the
feedstock, the output desired, or the like.
[0020] The bio-
char produced via the present process may have a calorific value of about
18 MJ/Kg or greater, about 22 MJ/Kg or greater, about 24 MJ/Kg or greater,
about 26 MJ/Kg
or greater, about 28 MJ/Kg or greater, about 30 MJ/Kg or greater. The present
bio-char may
have an energy density of about 4 MEL or greater, about 6 MEL or greater,
about 8 MEL or
greater, about 10 MEL or greater.
[0021] The
present bio-char may be hydrophobic. For example, if processed at
temperatures under about 400 C the bio-char may be hydrophobic. The present
bio-char may
be hydrophilic. For example, if processed at temperatures above about 400 C
the bio-char
may be hydrophilic. For example, the present bio-char may have a water contact
angle
ranging from about 102 to about 20 depending on process temperature.
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[0022] The
present biochar preferably is grindable. The coal industry uses the Hardgrove
Grindability Index ("HGI") as a standard test to measure grindability where
samples are
compared to a standard reference sample ("SRS"). For example, if the
grindability of a
sample was equal to the SRS coal, it would score 50. A score of less than 50
would indicate
a sample is harder to grind and a score of greater than 50 would indicate is
easier. The present
biochar preferably has a HGI of about 50 or greater, about 52 or greater,
about 54 or greater,
about 56 or greater, about 58 or greater, about 60 or greater.
[0023] The
present disclosure provides a reactor for converting biomass into biochar. The
reactor has at least one retort extending through it. For example, the reactor
may have two,
three, four, or more retorts. It is preferred that the reactor have at least
four retorts. The retort
may comprise a suitable conveyor such as, for example, an auger or paddle
conveyor, an inlet
and an outlet. The inlet receives biomass which passes through the reactor on
the auger to the
outlet.
[0024] The
reactor further comprises a heating system which heats the biomass as it
passes through the reactor. The heating system can heat the biomass to a
temperature suitable
to cause pyrolysis of biomass. The heating system may be any suitable design
such as, for
example, a plurality of heating elements, heat exchangers, or burners
throughout the length of
the reactor.
[0025] The
reactor comprises one or more thermosensors. The thermosensors may be
used to monitor the temperature of within the reactor enabling the temperature
to be kept at
the appropriate level to achieve the desired result. Multiple sensors may
allow for more
accurate assessment of the temperature at different points in the reactor. For
example, based
on the temperature reading the heating may be increased or decreased.
[0026] Certain
exemplary embodiments of the present disclosure comprise one or more
additional sensors such as, for example, a sensor for sensing the speed of the
auger. This
sensor enables the controller to assess the speed with which the biomass is
moving through
the retort. If this speed is too slow the controller may cause the speed to
increase or if the
speed is too fast the controller may cause the speed to decrease.
[0027] In
certain exemplary embodiments of the present disclosure, the reactor produces
a biochar stream and a gaseous stream. Biochar can have utility as a fuel
source, soil additive,
or the like. The gaseous stream may comprise condensable and non-condensable
components.
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The condensable components may, for example, be condensed to form pyrolysis
oil (bio-oil).
Bio-oil may be used as a petroleum substitute. The non-condensable gases (syn-
gas) may be
combustible and used, for example, to fuel the reactor heating system. The
biochar stream
may exit the reactor via a biochar delivery system such as described further
herein. The
gaseous stream may exit the reactor via a gas collection system such as
described further
herein.
[0028] The
present system may comprise a biochar delivery system for receiving the
biochar exiting the reactor. The delivery system receives the biochar stream
from the retort
via the outlet. The system may include a char cooling means. Any suitable
cooling means
may be used such as direct contact with a cooling medium, indirect contact
with a cooling
medium, direct contact fluid quenching, or the like. For example, the means
may be an auger
which moves the hot biochar through a cooling zone to compaction and/or
bagging area. An
airlock such as a rotary valve airlock may be positioned between the cooling
zone and the
compaction/bagging area. The cooling of the biochar may be aided by the
application of a
liquid such as water.
[0029] It is
possible enrich the biochar with additives such as nutrients or minerals. The
resultant biochar could derive advantageous properties from such enrichment.
For example,
when used as a soil additive the addition of nutrients and minerals markedly
improves the
performance of the product. Examples of minerals include, but are not limited
to, nitrogen,
sulphur, magnesium, calcium, phosphorous, potassium, iron, manganese, copper,
zinc, boron,
chlorine, molybdenum, nickel, cobalt, aluminum, silicon, selenium, or sodium.
Examples of
nutrients include compost tea, humic and fulvic acids, plant hormones, and
other solutions of
benefit to plant growth and soil health such as buffers, pH conditioners, and
the like.
[0030] The
addition of the additives to the bio-char may be achieved in any suitable
manner. For example, additives may be applied at the biochar delivery system.
Additives can
be introduced to the cooling liquid and applied to the biochar at the cooling
zone. As the
cooling liquid boils off the additives can be left behind on the char.
Additives may be
introduced as a solid and, for example, incorporated through mixing in the
cooling zone.
[0031] Gases
may exit the retort(s) via a gas collection system. The system may be in any
suitable form but can advantageously be a series of pipes dispersed throughout
the reactor
such that gas developed in the retort(s) during the pyrolysis process enters
the pipes and is
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carried out of the reactor. Where the reactor comprises more than one retort
it is preferred
that each retort have a separate gas collection pipe. Each retort may have
more than one gas
collection pipe. The separate pipes may feed into a gas collection module but
it has been
found that having separate pipes running from a section of the retort that has
been shown to
correspond with a particular biomass temperature and thermochemical stage of
decomposition (see Figure 3) to a common gas manifold improves efficiency of
gas
collection and reduces reactor downtime. The specific positioning of these
separate pipes
along the retort can improve efficiency.
[0032] The
reactor comprising one or more retorts, one or more thermosensors, and a
heating system may be in the form of a module. This can aid in the
transportation of the
pyrolysis system to various locations. The reactor module may also comprise a
gas collection
system.
[0033] The
present system comprises a syn-gas management system. The system is
adapted to receive the gaseous stream from the reactor, for example via the
gas collection
system. The gaseous stream may comprise condensable components. The syn-gas
management system may comprise a condenser to remove at least some of the
condensable
components to form bio-oil. The resultant oil may be stored in one or more bio-
oil storage
tanks. The system may comprise a pump such as, for example, a pump capable of
creating at
least a partial vacuum. The pump may be positioned downstream of the reactor,
but upstream
of the syn-gas and bio-oil collection tanks to facilitate gas movement from
retort to collection
tanks and combustion burners. The pump may take various forms, but will
preferably be
capable of conveying a corrosive, and high temperature gas stream. The pump
may be a
liquid-ring pump, a positive displacement pump, or any other suitable pump or
combination
of pumps. Preferred are pumps able to tolerate a temperature greater than
about 0 C, a
temperature greater than about 50 C, a temperature greater than about 100 C.
Suitable pumps
may be able to tolerate a temperature of less than about 600 C. The pump
preferably delivers
a pressure greater than about zero (0), but less than about two (2) pounds per
square inch
when measured at the tank or at the burner.
[0034] The syn-
gas may be stored in a syn-gas tank. The storage tank may have an inlet
for receiving the flow of syn-gas from the reactor and an outlet in fluid
communication with
the heating system and a flare pipe or other means for discharging the syn-
gas. The
communication may be controlled via a valve, such as a three-way valve,
configurable
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between a first position where flow is directed to the heating system and a
second position
where flow is directed to the flare pipe or other discharge means.
Alternatively the second
position may direct the flow of gas to a storage tank for later use.
[0035] The syn-
gas management system comprising the syn-gas storage tank, optionally
the condenser and bio-oil storage tank may be in the form of a module. This
aids in the
transportation of the pyrolysis system to different locations and improves the
ease of
implementation.
[0036] The
present system may comprise a controller, such as for example a
programmable logic controller. The controller may be in communication with the
thermosensor and the valve. The controller switches the valve from the first
position to the
second position upon receiving a signal from the thermosensor that, for
example, the
temperature in the reactor is above optimal levels. The controller may also
switch the valve
from the second to the first position upon receiving a signal from the
thermosensor that, for
example, the temperature in the reactor is below optimal levels. The
controller will frequently
be a microprocessor. The controller may be a separate module or may be a part
of one of the
other modules. As a separate module the controller can be located remote from
the pyrolysis
system. The controller may control more than just the valve. Depending on the
particular
embodiment the controller may control a variety of factors such as, for
example, the delivery
of biomass feedstock from the dryer to reactor, the residence time of biomass
in each retort,
the speed and/or pressure of vacuum pump(s), the residence time of biochar or
bio-coal in
any cooling portion of the system, the amount of additive added to biochar or
biocoal, the
speed of the retort, the speed of the conveyor, or the like, or any
combination thereof
[0037] The
present system may include a biomass dryer module. The drying can receive
biomass feedstock and may comprise a moisture sensor. The dryer receives
biomass and dries
it to reduce the moisture content. Preferably, the moisture content is about
20% or less, about
18% or less, about 15% or less. The dryer may be, for example, a flash dryer,
a belt dryer, or
a drum dryer. Once the desired moisture content is reached the biomass can be
fed into the
retort via the inlet means. A rotary valve airlock may be used between the
dryer and the
reactor in order to control the delivery of the biomass. In an embodiment of
the present
disclosure hot air from the reactor can be used in the dryer thus reducing the
need for external
heat sources in the dryer and improving the overall efficiency of the system.
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[0038] Any
suitable biomass feedstock may be used herein such as, for example, those
comprising wood fibre, agricultural fibre, by-products or waste (from plant or
animal
sources), municipal waste, or the like. The selection of biomass may vary
depending on
availability, the desired output and the particular application. Softwood-
fibre typically
comprises three major components: hemicellulose (25-35% dry mass), cellulose
(40-50% dry
mass), and lignin (25-35% dry mass). The energy content of wood fibre is
typically 17-21
GJ/tonne on a dry basis
[0039] The
feedstock may be in particulate form and may have an average particle size of
from about 1 mm to about 50 mm, such as from about 5 mm to about 25 mm. It is
preferred
that the feedstock have a moisture content of about 15% or less, such as about
10 % or less,
before commencement of pyrolysis.
[0040]
Depending on the nature of the biomass it may be necessary to prepare the
feedstock prior to pyrolysis. For example, the certain feedstocks may require
grinding to
produce particles of an appropriate particle size and/or shape. The present
method may
comprise a moisture removal step where the feedstock is heated to such a
temperature that
moisture is driven off
[0041] The
present disclose provides a method of producing bio-char. Figure 3a and 3b
summarizes the steps that may be present in said method. For instance, the
present method
may comprise a hemicellulose decomposition step. The hemicellulose
decomposition step
may be at a temperature of from about 200 C to about 280 C, such as about
220 C to about
260 C. The temperature may vary throughout the step or may stay constant. For
example, the
temperature may be increased at a rate of about 100 C/min or less, about 50
C/min or less,
about 35 C/min or less, about 20 C/min or less, about 15 C/min or less,
about 10 C/min or
less. The step may continue for any suitable length of time such as, about 1
minute or more,
about 2 minutes or more, about 3 minutes or more, about 4 minutes or more,
about 5 minutes
or more, about 10 minutes or more. It is preferred that by the end of the
pyrolysis at least
about 30%, at least about 40%, at least about 50%, at least about 60%, at
least about 70%, at
least about 75%, at least about 80%, at least about 85%, of the mass of
hemicellulose in the
feedstock has been decomposed.
[0042] The
present method may comprise a cellulose decomposition step. The cellulose
decomposition step may be at a temperature of from about 240 C to about 400
C, such as
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about 300 C to about 380 C. The temperature may vary throughout the step or
may stay
constant. For example, the temperature may be increased at a rate of about 100
C/min or
less, about 50 C/min or less, about 35 C/min or less, about 20 C/min or
less, about 15
C/min or less, about 10 C/min or less. The step may continue for any suitable
length of time
such as, about 1 minute or more, about 2 minutes or more, about 3 minutes or
more, about 4
minutes or more, about 5 minutes or more, about 10 minutes or more. It is
preferred that by
the end of the pyrolysis at least about 30%, at least about 40%, at least
about 50%, at least
about 60%, at least about 70%, of the mass of cellulose in the feedstock has
been
decomposed.
[0043] The
present method may comprise a lignin decomposition step. The cellulose
decomposition step may be at a temperature of from about 280 C to about 500
C, such as
about 400 C to about 500 C. The temperature may vary throughout the step or
may stay
constant. For example, the temperature may be increased at a rate of about 100
C/min or
less, about 50 C/min or less, about 35 C/min or less, about 20 C/min or
less, about 15
C/min or less, about 10 C/min or less. The step may continue for any suitable
length of time
such as, about 1 minute or more, about 2 minutes or more, about 3 minutes or
more, about 4
minutes or more, about 5 minutes or more, about 10 minutes or more. It is
preferred that by
the end of the pyrolysis at least about 5%, at least about 10%, at least about
15%, at least
about 20%, of the mass of lignin in the feedstock has been decomposed.
[0044] Yields
of bio-char, bio-oil, and syn-gas can be altered by varying the process
temperatures and/or heat transfer rates. While not wishing to be bound by
theory, it is
believed that higher temperatures tend to favour the production of bio-oil
and/or syn-gas by
driving off more of the condensable volatiles produced from decomposition of
cellulose.
Conversely, slow pyrolysis may favour the production of bio-char by limiting
the
decomposition of cellulose and reducing the amount of bio-oil produced. Bio-
coal production
can generally be maximized at temperatures of approximately 285 C. It is
believed that at
these temperatures hemicellulose still decomposes into syn-gas while much of
the cellulose
remains as a solid within the lignin matrix. By limiting the decomposition of
the cellulose
fraction, yields of bio-coal can be increased to around 70%. This type of
pyrolysis is known
as torrefaction and the resulting bio-char is referred to torrefied bio-char
or bio-coal.
Producing torrefied bio-char leads to a reduced amount of bio-oil thus
reducing the issues
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associated with storing and handling such oil. In addition, many industrial
scale kilns are
already equipped to handle solid fuels such as bio-coal rather than liquid bio-
oil.
[0045] Certain
embodiments according to the present disclosure may provide bio-char
yields in the range of from about 20% to about 80%, such as about 25% to about
70%. In
general, higher yields are seen with torrefaction than with other types of
pyrolysis. Certain
embodiments according to the present disclosure may provide bio-oil yields in
the range of
from about 10% to about 40%, such as about 20% to about 50%.
[0046]
According to a further aspect of the invention, a method for converting
biomass to
biochar is provided. The method comprises the steps of:
(a) introducing biomass to an interior of a retort in a reactor;
(b) advancing the biomass through the retort by means of a retort conveyor
such
as an auger extending therethrough, the temperature of the retort being
elevated to a point where pyrolysis of the biomass occurs;
(c) collecting biochar from the retort;
(d) applying an additive to the biochar;
wherein the additive is selected from soil nutrients and/or minerals. Examples
of
minerals include, but are not limited to, nitrogen, sulphur, magnesium,
calcium,
phosphorous, potassium, iron, manganese, copper, zinc, boron, chlorine,
molybdenum, nickel, cobalt, aluminum, silicon, selenium, sodium, compost tea,
humic acids, fulvic acids, plant hormones, pH conditioners, buffers, or
combinations thereof
[0047]
Referring to Figure 1, a general flow diagram of an exemplary biomass
pyrolysis
system can be seen. Biomass 1 is loaded into a dryer system 2. Biomass may be
any suitable
such as wood waste, agricultural waste, or any other organic material that can
be used to
produce bio-char. A rotary valve airlock 3 controls the feeding of the dry
biomass feed into a
reactor 4. The reactor produces a biochar stream which is fed to a cooling
zone 5. Cooling
water 6 and additives 7 may be applied to the biochar. A rotary valve airlock
8 controls the
movement of the cooled biochar to the compaction 9 and bagging 10 areas.
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[0048] The
reactor produces a gaseous stream which passes to a condenser 11 which can
condense condensable components such as bio-oil. The condensed bio-oil is
collected in a
bio-oil collection tank 12. A vacuum pump 13 moves the remain gaseous stream
to a oil tank
14, a syn-gas collection tank 15. The gaseous stream is fed to a three-way
valve 16. A
controller 18 receives a signal from a thermosensor (not shown) in the reactor
4. Depending
on the needs of the reactor the controller 18 can direct the valve via a
control signal 19 to
direct the syn-gas to a flare 17 or to the reactor 4 where the syn-gas can be
burnt by a furnace
(not shown).
[0049]
Referring to Figure 2, an overall side view of a biomass reactor system
according
to an embodiment of the present disclosure can be seen. Feedstock hopper 1
loads biomass
into a cyclone dryer system 2 which has an exhaust 3. Hot flue gas 5 from the
furnace 6 can
be used in the dryer assembly. A rotary valve airlock 4 controls the feeding
of biomass feed
into one or more anaerobic retorts 7. Biomass may be wood waste, agricultural
waste, or any
other organic material that can be burned to produce heat energy. Retorts 7
are tubular and
extend through furnace 6. The biomass is advanced through retorts 7 by augers.
Heat from
furnace 6 and the anaerobic conditions in retorts 7 pyrolize the biomass
advancing through
retorts 7, converting the organic feed to form a biochar stream and a gaseous
stream.
[0050] At
least a portion of the gaseous stream is collected by the gas collection
system 8
which comprises pipes leading to a gas collection manifold. The gases are then
fed into a
condenser 10 which can condense condensable components such as bio-oil. The
condensed
bio-oil is collected in a bio-oil collection tank 17 which the gaseous stream
is fed to a three-
way valve 19. Depending on the needs of the furnace 6 the valve can direct the
gas to a flare
18 or to syn-gas burners 9 via syn-gas pipe 20.
[0051] Biochar
at the downstream end of retorts 7 is collected and delivered to a cooling
retort with a water jacket and auger 13 . The assembly comprises a coolant
(water) tank 11
and an additive tank 12. The water and/or additive are applied to the biochar
via spray
nozzles 14. Cooled and improved biochar is the delivered to a collection bin
16 controlled via
a rotary valve airlock 15.
[0052] It is
contemplated that the different parts of the present description may be
combined in any suitable manner. For instance, the present examples, methods,
aspects,
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embodiments or the like may be suitably implemented or combined with any other
embodiment, method, example or aspect of the invention.
[0053] Unless
defined otherwise, all technical and scientific terms used herein have the
same meaning as is commonly understood by one of ordinary skill in the art to
which this
invention belongs. Unless otherwise specified, all patents, applications,
published
applications and other publications referred to herein are incorporated by
reference in their
entirety. If a definition set forth in this section is contrary to or
otherwise inconsistent with a
definition set forth in the patents, applications, published applications and
other publications
that are herein incorporated by reference, the definition set forth in this
section prevails over
the definition that is incorporated herein by reference. Citation of
references herein is not to
be construed nor considered as an admission that such references are prior art
to the present
invention.
[0054] Use of
examples in the specification, including examples of terms, is for
illustrative purposes only and is not intended to limit the scope and meaning
of the
embodiments of the invention herein. Numeric ranges are inclusive of the
numbers defining
the range. In the specification, the word "comprising" is used as an open-
ended term,
substantially equivalent to the phrase "including, but not limited to," and
the word
"comprises" has a corresponding meaning.
[0055] The invention includes all embodiments, modifications and variations
substantially as hereinbefore described and with reference to the examples and
figures. It will
be apparent to persons skilled in the art that a number of variations and
modifications can be
made without departing from the scope of the invention as defined in the
claims. Examples of
such modifications include the substitution of known equivalents for any
aspect of the
invention in order to achieve the same result in substantially the same way.
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