Note: Descriptions are shown in the official language in which they were submitted.
CA 02757061 2011-10-20i
MOBILE PLANT FOR THERMALLY TREATING A CONTAMINATED OR
UNCONTAMINATED FEED STREAM, PROCESSES THEREOF AND USES OF PRODUCTS
THEREOF
FIELD OF THE INVENTION
The invention relates to a mobile plant comprising a reactor for thermally
treating a contaminated
or uncontaminated feed stream such as a feed oil. The mobile plant also
produces oils to be used
for cleaning tank bottoms for ships, tank farms and equipment fouled by heavy
hydrocarbons
material.
The present invention also relates to a process to thermally treat used
lubricating oils, waste oils,
oily tank bottoms, heavy oils or bitumen in a rotating kiln operating under
pressure with the
injection of a gas, preferably of a sweep gas into the reactor of the mobile
plant or its feed stream.
The present invention also relates to the use of oils with resins, such as
cracked or polarized oils,
for cleaning equipment or materials that are fouled or contaminated with
hydrocarbons or with
other contaminants.
The present invention, also relates to the use of the mobile plant for
preparing specialty oils and
the use of these oils in specific applications.
The processes of the invention may be used in various environmental
applications and the
products thereby obtained are useable in various environmental way such as
fuels, specialty oils,
for cleaning fouled equipment and materials, and site specific applications.
BACKGROUND OF THE INVENTION
Waste oils, especially used lubricating oils (ULO), are considered a threat to
the environment, and
are classified as a hazardous product in most jurisdictions. The Environment
Protection Agency
(EPA) states that: "One gallon of used lubricating oil can pollute a million
gallons of water."
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Presently water is used to clean ships bunker reservoir, tank farm bottoms and
other equipment
that is fouled by heavy oils and/or other hydro-carbon residue. This means
that the water used
has to be separated from the oily residues and then the residues treated or
burned in ciment kilns.
The burning of the oily residues is bad for the environment and a waste of the
hydrocarbon
resources.
There are many processes to treat waste oils. Up until the December 2001
report to the European
Commission of the Environment by Taylor Nelson Sofres titled "Critical review
of existing
studies and life cycle analysis on the regeneration and incineration of waste
oils", and the
November 19, 2008 European union directive, there was priority given to re-
refining processes
recycling waste oils into lubricating oils in the European Union as well as in
the rest of the World.
Consequently many re-refining processes were invented and used. The commercial
re-refining
processes used in Europe are described in the Taylor Nelson Sofres report.
These and others are
described in a book by Francois Audibert titled "Waste Engine Oils, Re-
refining and Energy
Recovery", (Elsevier, Amsterdam, 2006). Among the processes that regenerate
ULO into
lubricating oil base-stocks, some, such as the acid clay processes, were
abandoned or legislated
out because of the disposal costs, both financial and environmental, of the by-
products such as
spent acid and clays.
Lube oil regeneration processes, using solvent extraction or vacuum
distillation as their primary
process, require a finishing step, such as hydrotreating, which entails the
purchase of hydrogen or
building a hydrogen unit. Usually, the quality of their feedstock determines
the quality of their
products. Waste oil compositions are variable, and can change even within a
shipment. Re-
refining processes usually require extensive laboratory analyses of both the
waste oil entering the
plant, to determine the amount of chemicals to add in their pre-treatment
processes, and of the
product lubricating oils to ensure consistent product quality. Because of
their high capital and
operating costs, these plants must be close to large population centre and/or
serve a large
collection area, and usually require government subsidies to be viable.
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When the used oil is to be used as fuel, chemical treatment of ULO to extract
heavy metals,
sulphur and chlorides is legislated and requires considerable laboratory
analyses because of the
constant variations in feedstock compositions.
In some very specific and rare applications, ULO is cleaned, dewatered, tested
and its additive
package is topped-off, before the lube oil is used again without leaving the
plant site. Again, these
applications require extensive laboratory analyses.
The re-refining processes alluded to in the previous section aim to recover
lubricating oils from
the used oil feed streams. There are processes aimed at destroying the metal-
containing additives
in waste oils, and make environmentally acceptable products such as fuels.
Corresponding
proposed stationary reactors, operating at atmospheric pressure, are mentioned
in the following
patent literature.
In Canadian Patents 1,309,370, and 2,112,097, and in US Patents 5,271,808 and
5,795,462 Shurtleff
speaks of: An apparatus and a method that are provided reclaiming a useful oil
product from
waste oil, such as used lubricating oil. The apparatus comprises an oil feed
means, a boiler, a
heater and a separating means. The heater is used to heat the waste oil in the
boiler to a
temperature such that heavier hydrocarbons remain unvolatilized, trapping
contaminants
therewith. The separating means separates the volatilized lighter hydrocarbons
from the
unvolatilized heavier hydrocarbons and contaminants.
In US Patent 5,871,618 and Canadian Patent 2,225,635, Kong at Al. speak of an
apparatus and a
process for reclaiming fuel oil from waste oil. The apparatus comprises a
thermal cracking unit
for cracking the high boiling hydrocarbon material into lighter, lower
boiling, material so as to
separate hydrocarbon vapor products from viscous materials; a condenser/ heat
exchanger for
condensing the hydrocarbon vapour products to the liquid state; a fuel
stabilization unit for
chemically treating the condensates so as to give an oil product and solid
sediment; and a
polishing unit for forming a high quality fuel oil by physically removing
solid contaminants.
According to the present invention, high quality fuel oil can be obtained
together with an
environmentally innocuous solid ash cake, through a simple and efficient
process.
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In US Patent 5,362,381, Brown et Al. speak of a process in which waste
lubricating oil is
reprocessed into commercially usable diesel fuel and naphtha by
thermocracking. A
thermocracker unit is fired with sludge removed from the principal pool of oil
undergoing
vaporization. The vapours are separated from liquids in a primary distillation
tower with
precisely controlled heating. Resultant vapours are partially condensed.
Resultant liquids flow
downward through a secondary distillation tower into a reboiler which is
heated by a flue gas
bypass with an auxiliary burner. Vapours leaving the secondary distillation
tower are partially
condensed and resultant fluids are passed to a light ends flash tank. Gases
from the flash tank
fuel the auxiliary burner. Liquids are collected and stored for selling as
naphtha. Hot liquids are
withdrawn from the reboiler and are immediately cooled to atmospheric
conditions. Liquids
within specification are stored in a diesel storage tank for further use and
sale. Off-specification
products are stored in a reflux storage tank and are pumped and heated and
sprayed downward
in the primary distillation tower for washing the tower and for reprocessing
in the
thermocracking unit. Some light ends are mixed with sludge in a storage tank.
The mixture is
pumped as sludge fuel to the burner in a fire tube in the thermocracking unit.
In US Patent 5,885,444, Wansborough et Al. speak of a process for thermally
cracking waste motor
oil into a diesel fuel product is provided. The thermal cracking process uses
low temperature
cracking temperatures from 625F to 725F with ambient pressure to generate a
column distilled
fraction of diesel fuel mixed with light ends, the light ends being flashed
off to produce a high
quality #2 diesel fuel. The process further provides for removal from the
cracking vessel an
additional product stream which, when filtered, is suitable for use as a #3
fuel oil and that can be
further blended with a bunker oil to yield a #5 fuel product.
In Canadian Patent 2,242,742, Yu speaks of a process and apparatus for the
reclaiming and re-
refining of waste oils. The process comprises raising a temperature of a feed
mixture of fresh
waste oil and a recycled non-volatile residue to a range of 400 C to 490 C
for a time sufficient to
cause pyrolysis of said heavy hydrocarbons contained in the feed mixture, but
insufficient to
permit substantial undesired polymerization, oxidation and dehydrogenation
reactions to take
place in said feed mixture; cooling the resulting pyrolized waste oil mixture
to a temperature in
the range of 300 C to 425 C, and maintaining said temperature while allowing
volatile
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components in the pyrolyzed waste oil mixture to evaporate, leaving a non-
volatile residue
containing said contaminants; condensing the evaporated volatile components to
form a
reclaimed oil product; and mixing the non-volatile residue with fresh waste
oil to form more of
said feed mixture and repeating said temperature raising, cooling, evaporation
and mixing steps
on a continuous basis, while continuing to condense volatile components
evaporated from said
pyrolyzed waste oil mixture. The apparatus comprises a heating unit, a
container, a condenser
and pumping equipment and piping. The process and apparatus of the present
invention
generate #2 diesel fuel, gasoline and coke from waste oil. In this patent, the
reactor operates
under positive pressure.
Among the problems common to stationary reactors in waste oil applications are
coking of the
reactor walls, which impedes heat transfer from the heat source to the oil to
be treated, and
fouling of the equipment, not only in the reactor but also upstream and
downstream of the
reactor.
In US Patent 6,589,417, and Canadian Patent 2,314,586, Taciuk et Al. speak of
a process by which
used oil is treated in a reactor to remove contaminants. The reactor comprises
a rotating vessel
housed within a heating chamber. The inside of the vessel is indirectly heated
by conduction
through the vessel walls. The vessel contains a permanently resident charge of
non-ablating,
coarse granular solids. Within the vessel, the oil is vaporized and pyrolyzed,
producing a
hydrocarbon vapour. Coke is formed as a by-product. Contaminants, such as
metals and halides
become associated with the coke. The coarse granular solids scour and
comminute the coke to
form fine solids. The fine solids are separated from the coarse solids and are
removed from the
vessel. The hydrocarbon vapours are separated from any fine solids and are
routed to a vapour
condensation system for producing a substantially contaminant-free product
oil. The
contaminant-rich solids are collected for disposal. This process operates at a
negative pressure in
the reactor.
Rotating kilns, operating under vacuum, are suggested in processes designed to
thermally crack
bitumen, heavy oil, rubber tires, oil shale and oil sands, coal or refinery
distillation column
bottoms.
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In Canadian Patent 1,334,129, Klaus speaks of an invention that relates to a
process and
apparatus for the pyrolysis of bitumen. The process involves spraying
preheated bitumen into a
generally horizontal cylindrical rotating reactor which is heated from the
outside and which
contains grinding bodies. The bitumen is heated to the pyrolysis temperature
and thereby forms a
gaseous product and a solid pyrolyzed coke. The solid pyrolyzed coke is
removed from the
reactor walls by the grinding bodies and the resulting small particles are
continuously removed
from the reactor through ports in the reactor wall.
In US Patent 4,473,464, Boyer et Al. speak of a method for producing a
distillable
hydrocarbonaceous stream and carbonaceous agglomerates from a heavy crude oil
by charging
the crude oil and finely divided carbonaceous solids to a rotary kiln with the
crude oil and
carbonaceous solids being charged in a weight ratio from about 0.6 to about
1.5; tumbling the
crude oil and finely divided carbonaceous solids in the rotary kiln at a
temperature from about
850F to about 1000F for up to about 30 minutes to produce a vaporous stream
and agglomerate
particles containing a residual portion of the crude oil and finely divided
carbonaceous solids;
separating the agglomerate particles into a product portion of a desired
particle size range and a
recycle portion; grinding the recycle portion to produce the finely divided
carbonaceous solids
and heating the finely divided carbonaceous solids prior to recycling the
carbonaceous solids to
mixture with the crude oil, an improvement comprising: supplying at least a
major portion of the
heat required in said rotary kiln by heating the crude oil charged to the
rotary kiln thereby
eliminating the heating of the finely divided carbonaceous solids prior to
recycling.
In US Patent 4,439,209, Wilwerding speaks of an apparatus for the continuous
non-oxidative
thermal decomposition of heat-dissociable organic matter to a solid carbon
residue, particularly
activated carbon, and a mixture of gaseous products, without substantial
coking or tar formation.
The apparatus involve a cylindrical rotating drum in a substantially
horizontal position, into
which feed material is introduced at one end and products recovered at the
other end. An axial
temperature gradient, increasing in the direction of flow, is maintained
within the drum, enabling
the exercise of a high degree of control over the reaction to fully convert
the feed into the desired
products.
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Indirectly fired rotating kilns are usually considered inefficient means to
convey heat into a
reactor. Some propose heating the reactor feed with a hot stream. The hot
stream can be
circulating gas, liquid or solids.
In US patent 5,423,891, Taylor proposes a direct gasification of a high BTU
content fuel gas from a
hydrocarbon content solid waste material W which may include some glass
content is effected by
preheating heat carrier solids HCS in a flash calciner to a temperature
capable of thermally
cracking the hydrocarbon content of the solid waste material W directly into
the high BTU
content fuel gas. The HCS are separated from the products of combustion and
fed into a gas
sealed refractory lined horizontal axis rotary kiln retort concurrently with
the solid waste W.
Momentary contact and mixing of the solid waste W with the HCS in the rotary
kiln in the
absence of oxygen is sufficient to directly thermally crack the solid waste
material into the high
BTU gas product. Separated HCS are returned to the flash calciner for
reheating. A trommel,
coupled directly to the output of the rotary kiln retort and having a trommel
screen with mesh
openings smaller than glass agglomerates, but sized larger than the HCS,
permits separation of
the HCS and discharging of glass agglomerates from the downstream end of the
trommel screen
to prevent shut down of the direct gasification unit. Direct gasification of
steel industry waste
water treatment plant sludge, automobile shredded refuse ASR, municipal solid
waste MSW and
refuse derived fuel RDF and oil mill scale is effectively achieved,
irrespective of glass content
contaminant.
In US Patent 4,512,873, Escher speaks of a process in which the residues
obtained in the
hydrogenation of oil, especially heavy oil, or of coal are subjected to low
temperature
carbonization in a drum, preferably a rotary drum, at temperatures between
approximately 400 C
and approximately 600 C, by means of a carbonization gas after the separation
of the condensable
portions and heating to temperatures between approximately 600 C and
approximately 950 C,
which is introduced into the low temperature carbonization drum. The gas is
heated to
temperatures between approximately 600 C and approximately 950 C indirectly by
flue gases
arising from the combustion of oil or gas, for example, of excess
carbonization gas. The residue to
be carbonized at low temperature is introduced into the hot gas in a finely
dispersed state and
preferably atomized.
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From a practical point of view, it is difficult to ensure the integrity of the
seals of both the main
reactor and the coke incinerator when there is a circulating stream of solids.
When produced gas
is circulated to heat the reactor feed oil to cracking temperatures, large
amounts of circulating gas
is required, compared to the fresh feed stream.
Attempts have been made to provide the industry with a transportable plant
able to purify
contaminated oils and refine oils in general.
In US patent 4,039,130, Hogan proposes a portable skid mounted fully equipped
topping plant for
the distillation of gasoline and diesel fuel from crude oil feed, equiped with
its own power
supply, capable of producing its own electricity and power requirements,
utilizing fuel from
crude oil feed, and designed for automatic operation and equipped with an
automatic shut-down
system. The system input is crude oil (not waste oil) and its stated output is
diesel.
In US patent 5,316,743 Leblanc proposes a portable refinery including a
refining vessel (a system
similar to a horizontal distillation tower) a heater for providing heat to the
refining vessel,
dewatering devices, and a storage tank mounted on a skied which can be quickly
and easily
transported to a reservoir of petroleum products to refine the petroleum or
waste petroleum into
diesel grade fuel at the reservoir. It works At about 630 degrees F or about
330 degrees C.
In US patent applicationUS2009/ 0095683 Al Zulauf proposes a mobile fuel
filter for removing
sulfur-containing compounds from a diesel fuel. The system and methods are for
the removal of
sulfur containing compounds that provide for the production of fuel streams
having
concentration of less than 15 ppm.
In US patent 7,510,647 Evans proposes a mobile fluid catalyst injection system
and a method of
controlling a fluid catalyst cracking process is provided. In one embodiment,
a mobile fluid
catalyst platform and a flow control device coupled to the platform and a flow
control device
coupled with an outlet of the reservoir and adapted to control the flow of
catalyst from the
reservoir to a fluid catalyst cracking unit (FCCU).
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In US Patent 7,951,340 Brons, Wright, Lutz and Greaney propose an atmospheric
and/or vacuum
resid fractions of a high solvency dispersive power (HSDP) crude oil are added
to a blend of
crude oil to prevent fouling of crude oil refinery equipment and to perform on-
line cleaning of
fouled refinery equipment. The HSDP resid fractions dissolve asphaltene
precipitates and
maintain suspension of inorganic particulates before coking affects heat
exchange surfaces.
In US patent 2010/0147333 Wright, Brons, Feiller and Lutz propose Non-high
solvency dispersive
power (non-HSDP) crude oil with increased fouling mitigation and on-line
cleaning effects
includes a base non-HSDP crude oil and an effective amount of resins isolated
from a high
solvency dispersive power (HSDP) crude oil, and method of making same. Also,
methods of
using such non-HSDP crude oil for on-line cleaning of a fouled crude oil
refinery component, for
reducing fouling in a crude oil refinery component, and in a system capable of
experiencing
fouling conditions associated with particulate or asphaltene fouling.
None of those prior art mobile plants was effectively commercialized due to
several drawbacks
such as not being able to treat a wide variety of waste oils, providing
readily useable products
with no environmentally harmful by-products.
There was therefore a need for a process allowing for the on-site treatment of
the oils coming
from the cleaning of fouled equipment and/or materials. None of the prior
processes used
cleaning oils containing a high concentration of resins (polarized
hydrocarbons) as cleaning
agents for fouled equipment and materials that have deposits of hydrocarbons
and other
materials such as asphaltenes, tars, coke, salts, dirt, gums, and resins.
There was therefore a need for a transportable flexible and viable process
unit that addresses at
least one of the drawbacks of existing technologies.
There was also a need for a transportable unit that can destroy the harmful
components in waste
oils.
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The was additionnally a need for a transportable unit that can destroy the
harmful components in
waste oils while making products and by-products.
The was also a need for a transportable unit that can destroy the harmful
components in waste
oils while making products and by-products that are useful and environmentally
friendly and
commercial way.
The was further a need for a transportable unit that can destroy the harmful
components in waste
oils while making products and by-products that are useful, environmentally
friendly and of a
commercial interest.
There was also a need for a transportable unit that can destroy the harmful
components in waste
oils and that can be operated in a commercial way.
Additionnally, there was a need for a viable, safe and flexible process that
can destroy the
hazardous components in waste oils while making products and by-products that
are all
environmentally friendly.
There was also a need to have a process for cleaning in an efficient and
environmentally friendly
for fouled tank farms and boat reservoirs and equipment with products that can
be treated on
premises.
There was further a need for adequate amounts of a cleaning oil which can
dissolve and/or
combine with fouling material to remove it. There was a need to dispose of the
materials coming
from the cleaning process in an environmentally friendly manner.
There is a need for a viable and flexible process that can destroy the
hazardous components of
ULO and produce useful products with little or no by-products to dispose of in
industrial
landfills or incinerators.
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ABSTRACT
Mobile plant, for thermally treating a feed stream, comprising a first unit
designed for heating the
feed oil (Unit I); ii. a second unit comprising a rotating reactor designed to
perform the thermal
processing (pyrolizing) of the feed oil and a vapour solid separator (Unit
II); and iii. a third unit
(Unit III) that is a product separation unit and that is preferably configured
for recycling at least
part of the treated feed stream (heavy oil), recovered in Unit III, into Unit
I. The first unit and or
the second unit is (are) configured for injecting a sweep gas in said feed oil
and or in said rotating
reactor, and/or the second unit is configured in a way that the rotating
reactor may work under
positive pressure. The processes for thermally treating a feed material by
using a mobile plant.
The uses of the processes for various environmental and non environmental
applications.
Processes for manufacturing the mobile plants. Uses of oil containing resins
(such as cracked
and/or polarized oils) for cleaning purposes and other specialty applications.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1: represents a cross section, according to a plan perpendicular to the
horizontal axis, of a
reactor and the charge of metal plates and the shelves tacked on the kiln
walls of a reactor
according to a first embodiment of the present invention wherein the reactor
cross section
has 34 shelves. In this example, the shelves are spaced to allow for only two
rows of plates
per shelf, one layer against the reactor wall, the other against the first
row.
Figure 2: represents a cross section, according to a plan perpendicular to the
horizontal axis, of a
reactor and the charge of metal plates and the shelves tacked on the kiln
walls of a
reactor according to a second embodiment of the present invention wherein the
reactor
cross section has only 4 shelves, each pushing two layers of enough plates to
cover at
least a quarter of the reactor wall.
Figure 3: represents a cross section, according to a plan perpendicular to the
horizontal axis, of a
reactor and the charge of metal plates and the shelves tacked on the kiln
walls of a
reactor according to a third embodiment of the present invention, as described
in the
"Preferred Mode" section of this application, wherein the reactor has only one
shelf.
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Figure 4: represents a cross section of a bracket as present in the reactor
represented in Figure 2
with sections of shelves, seen from the top.
Figure 5: represents the bracket of Figure 4 shown from an end.
Figure 6: Illustrates an example of the exit end of the kiln represented in
Figure 1 with 4 scoops.
Figure 7: is a cross section of a reactor, according to an embodiment of the
invention, in the
horizontal position and wherein the feeding of the material to be treated and
the exit of
the vapours and the solids produced are both on the left side of the reactor.
Figure 8A: is a cross view of a first embodiment of the center ring supports
for the feed line inside
a cylindrical reactor of the invention, when the reactor is cool.
Figure 8B: is a cross view of a second embodiment of the center ring supports
for the feed line
inside a cylindrical reactor of the invention, when the reactor is cool.
Figure 8C: is a cross view of a third embodiment of the center ring supports
for the feed line
inside a cylindrical reactor of the invention, when the reactor is heated.
Figure 8D: is a detailed perspective view of the attachments means of the
invention that allows
the support beams to expand and rotate at their junctions points with the
reactor walls
and rings, when the reactor is heated.
Figure 9: is vertical cross section of reactor according to an embodiment of
the invention in a
slanted position.
Figure 10A: is a front view of a screen made of wire mesh.
Figure 10B: is a front view of a screen made of a perforated disc.
Figure 11: is a vertical cross section of a reactor according to an embodiment
of the invention in a
slanted position wherein the feeding of the material to be treated and the
exit of the
thereby obtained vapours and solids are on opposite side of the reactor.
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Figures 12 A and 12 B: are a further alternate embodiment of the rotating
reactor of the invention
wherein heating is performed inside the reactor.
Figure 13: is a vertical cross section of a reactor of the invention made up
of two cones joined at
the base.
Figure 14: is a vertical cross section of a reactor of the invention in a
slanted position with a
configuration particularly suited for treating heavy oils feedstocks that may
produce
more solids or more cokes or contain sand or contaminated soils.
Figure 15: is a simplified flow sheet of the mobile plant for thermally
treating contaminated feed
oil, the transportable plant comprising a rotating reactor as represented on
Figure 1 to 14.
Figure 16: illustrates how all the equipment in figure 15 can be transported
on a flatbed truck, or
inside a container.
Figure 17: is a plot plan showing the equipment once deployed on site.
GENERAL DEFINITION OF THE INVENTION
Preliminary definitions
For the purpose of this document, the following definitions are adopted:
- Feed stream: is a constituted of liquids and /or of solids, preferably the
feed stream is a feed
oil, that is selected in the group constituted by a contaminated oil and/or an
uncontaminated waste oil, wherein said oil is advantageously a synthetic oil,
a natural oil,
a vegetable oil, an animal fat oil. The feed stream may also be constituted of
oily tank
bottoms, oily water, marpol, asphalts, oily beaches, contaminated soils, oil
sands and/or
tars, heavy oils, tires, process oils, and any mixture containing one or more
of these oils.
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- Sweep gas: is any non reactive or substantially non reactive gas,
preferably it is an inert gas
such nitrogen or water steam; it has surprisingly be found that such gas not
only have as
sweeping effect in the reaction zone of rotating operating reactor, but
creates a positive
pressure. This may incidentally increase the safety of the operation and/or
improve the
efficiency of the process.
- Contaminants: in waste oils, the most common contaminant is water.
Other contaminants
include, but are not limited to, sand, clay, engine wear products, and
decomposition
products from oils, greases and/or additives.
- Diesel, gasoil or fuel oil: in the context of this process are oils
mainly made up of
hydrocarbons with boiling points between 100 C and 5000C, according to ASTM D-
86.
- Naphtha: a light oil with a 90% point (ASTM D-86) around 160 C, and a
specific gravity
between 0.65 and 0.8.
- Used Lubricating Oil (UL0): Oils or greases that were used as
lubricants, usually in engines,
and were discarded. Examples would include car engine oils, compressor oils,
and diesel
engine oils among others. Lubricating oils generally contain additives, which
are carefully
engineered molecules added to base oils to improve one or more characteristic
of the
lubricating oil for a particular use. Used lubricating oil is classified as a
hazardous product
in many jurisdictions because of its additives and contaminants.
- Substantially non reactive gas: a gas that does not readily interact
with the feed or product
oils in the reactor.
- Waste oils: Oils or greases that are discarded. They include ULO as
well as a wide range of
other oils such as marpol, refinery tank bottoms, form oils, metal working
oils, synthetic
oils and PCB-free transmission oils, to name a few.
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- Consistent shapes: means shapes so they can stay on the narrow shelves
and/or each other,
while protecting the reactor wall from direct contact with the relatively cold
feed.
- Thermal processing : is preferably at least one of the followings:
evaporating, cracking,
drying, pyrolizing and thermocleaning.
- The height of a shelve: is the distance between the attachment point of the
shelve on the
reactor wall and the end of the shelve directed to the center of the reactor.
- The width of a shelve: is the measurement of the distance between the two
sides of the shelve
on a direction perpendicular to the height of the shelve.
- oils containing resins: is a mixture of oils that contain cracked and/or
polarized oils.
- plates: is substantially flat or a flat piece of a solid material such as
stone or metal or other
material non ablating at reactor operating conditions or a smooth flat thin
piece of
material. In the context of this invention, substantially flat means also
slightly concave or
convex in at least one direction of the plate and on at least one face of the
plate, more
preferably the curve plate is adapted to the form of the reactor.
Substantially also means
that a plate may be for at least 70%, preferably for at least 80 %, more
preferably for at least
95 % of its surface, flat.
A first object of the present invention is constituted by the family of mobile
plants for thermally
treating a feed stream said mobile plant comprising a first unit designed for
heating the feed oil
(Unit I), a second unit comprising a rotating reactor designed to perform the
thermal processing
(pyrolizing) of the feed stream and a vapour solid separator (Unit II); and a
third unit (Unit III)
that is a product separation unit and that is preferably configured for
recycling at least part of the
treated feed stream (heavy oil), recovered in Unit III, into Unit I. In these
mobile plants the first
unit and/or the second unit is (are) advantageously configured for injecting a
sweep gas in said
feed oil and or in said rotating reactor, and/or the second unit is
advantageously configured in a
way that the rotating reactor may work under positive pressure.
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Those mobile plants are particularly suited for treating a feed stream that is
a feed oil, and more
preferably a contaminated oil or an uncontaminated oil.
According to a preferred embodiment, the mobile plants of the invention, when
used for
thermally treating a feed oil, are configured in a way that said first unit
contain no sub-unit for
chemically treating, preferably for purifying, said feeding stream before its
injection into Unit II.
Advantageously, is designed to remove the water from the feed oil when water
is present in said
feed stream (oil).
According to a preferred embodiment, said rotating reactor comprises:
a. a rotating kiln, which rotating kiln preferably containing plates;
b. a heating system;
c. at least one shelf on the reactor wall;
d. a charge of plates of consistent shapes;
e. means for bringing the mixture to be thermally processed on the surface of
at least
part of the plates;
f. means for removing the solids from the reactor, preferably either through
entrainment with the exiting vapours, or through a separate solids exit, or
both;
g. means for recovering the reaction and straight run products; and
h. means for venting the gas obtained by the thermal processing outside the
reactor
zone.
In the meaning of the present application, the charge of plates may be
constituted of various type
of plates, each plate of a particular type being consistent in form with the
form of other plates of
the same type. The charge of plates may be constituted by an assembly of
plates of the same type
and consistent in form.
Advantageously, at least one shelf is placed on the reactor wall in such a way
to keep a uniform
distribution of the plates along the reactor length. In the rotating kiln, the
at least one shelf is
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preferably either parallel to the center axis of the reactor, when the reactor
is horizontal, or
slanted with respect to the centre axis when the reactor is slanted or not
slanted.
Said means for bringing the mixture to be thermally processed on the surface
of at least part of
the plates, are configured in a way to bring the said mixture on the surface
of at least more than
10% of the plates, preferably on the surface of at least more than 30 % of the
plates, and more
advantageously on the surface of about 50 % of the plates present in said
reactor.
According to a preferred embodiment, the reactor and its internals for thermal
processing is
configured to rotate around its centre axis, the said axis forming with the
horizontal an angle that
is less than 45 degrees, preferably less than 30 degrees and more preferably
this angle is about 5
degrees and more advantageously the angle is of 0 degree.
Advantageously, in the mobile plants of the invention, the center axis of the
rotating kiln is
horizontal or slanted and said angle is maintained constant except in the case
wherein solid
agglomeration occurs or when the reactor is cooled down after operation.
Said reactor is preferably configured in a way that the walls of said reactor
are directly and/or
indirectly heated and/or in a way that said reactor is configured in a way
that the inside of the
reactor is directly and/or indirectly heated.
The heat source is advantageously generated by electricity, a hot oil and/or
gas stream, or
obtained from the combustion of gas, naphtha, other oily streams, coke, coal,
or organic waste or
by a mixture of at least two of these.
According to other embodiment, said reactor is configured in a way that the
inside of the reactor
is indirectly heated by an electromagnetic field and/or the inside of the
reactor is directly heated
by a hot gas, liquid or solid stream, electricity or partial combustion of the
feedstock, coke,
products or by-products.
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The heating means advantageously comprise at least one heating system external
to the walls of
the reactor, which is usually the case of an indirectly fired kiln.
Advantageously, the external walls of the reactor are at least partially
surrounded by one or more
burners and/ or exposed to combustion gas and/ or hot solids.
According to another embodiment, the walls of said reactor are surrounded by a
fire box, and
said fire box is stationary and contains one or more burners.
In the rotating kiln, one or more shelves are advantageously attached to the
internal walls or the
external walls of said reactors. The shelve (s) is (are) are preferably
attached to the wall of said
reactor in a way allowing for the thermal expansion of the shelves with
minimum stress on the
reactor walls and on the shelve(s). According to a specific embodiment, the
shelve(s) is(are) held
by T shaped clamps. Advantageously, the shelve(s) is(are) symmetrically
attached to the internal
wall of said reactor the shelve(s) is(are) attached to the internal wall in a
designed and/or random
pattern of said reactor.
The number of shelve(s) that is(are) disposed, per square meter of the
internal surface of the
reactor, on the internal wall of said reactor ranges advantageously from 1 to
40, preferably from 2
to 20.
The number of shelve(s) that is(are) disposed, per square meter of the
internal surface of the
reactor, on the internal wall of said reactor ranges advantageously from 1 to
50 units, more
advantageously from 2 to 20, preferably from 3 to 15 and this number is more
advantageously
about 4.
The number of shelves in the reactor depends on the weight and/or on the size
and/or on the
form of the plates and/or on the maximum operating temperature of the reactor
wall and/or on
the material the shelves and plates are made of.
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The space between two shelves represents from 0 to 100 % a preferably from 5%
to 100% of the
radius of the cylinder.
Advantageously, the space between two shelves represents from 10% to 100% of
the radius of the
cylinder; this space is preferably about 25% of the radius of the reactor that
is preferably a
cylinder.
According to a preferred embodiment, the distance between two shelves
represents from 5 % to
100 % of the circumference of the inner wall of the reactor that is preferably
a cylinder, more
preferably a cylinder with conic ends.
According to another preferred embodiment, the distance between two shelves
represents from
10 to 100%, this space being preferably about 25% of the circumference of the
inner wall of the
reactor that is preferably a cylinder. The form of the shelves is preferably
selected in the group
constituted by flat, concave, convex, spiral and slanted.
According to a preferred embodiment, the shelves are slanted in relation to
the reactor axis, the
angle between the reactor axis and the shelves is the same as that between the
reactor axis and the
horizontal, and preferably the angle between the reactor axis and the
horizontal can range from 00
to 300 and is more preferably 0 .
Advantageously, the height and/or the width of the shelves is calculated and
depends on at least
one of the following parameters: the space between the shelves, the space
between the supports
(the "T" brackets), the material the shelves are made of and the weight of the
plates. Preferably,
the height or width of the shelves ranges from 1 to 8 cm. More preferably, the
height or width of
the shelves ranges from 1.5 to 4 cm, and said width is preferably about 2.5
cm, more preferably
about 2.
According to another embodiment, the width and the height of the shelves are
selected in order
for the shelves to be able to retain 2 to 3 plates. Advantageously, the height
of the shelves is at
least about the thickness of the plates, preferably about twice the thickness
of the plates.19
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CA 02757061 2011-10-20 I
The shape of the plates of the charge is advantageously selected among the
group of
parallelograms, such as square, rectangles, lozenges, or trapezes. More
advantageously, the plates
of the charge are rectangular, triangular, hexagonal or octagonal. The shape
of the plates of the
charge may be perfect or imperfect, or about perfect.
According to a preferred embodiment, all the plates present in the rotating
kiln have about the
same size and shape.
The volume of the plates of the charge present in the reactor may represent
from 1% to 25% of the
internal volume of the said reactor. Advantageously, the volume of the plates
of the charge
present in the reactor represents about 4%, of the internal volume of the said
reactor.
According to another embodiment, the charge of the reactor is constituted by
flat and/or slightly
curved metal plates of consistent thickness and shape.
Plates having a melting point which is at least of 100 degrees Celsius, and
more preferably that is
of at least 150 degrees Celsius above the reactor wall maximum operating
temperature in the
thermal processing zone, are particularly suited.
Advantageously, the plates are heavy enough to scrape coke or other solids off
the reactor wall
and/or off other plates.
According to a preferred embodiment, most of plates and preferably each plate
present in the
rotating kiln, has a density that is superior to 2.0 g/cm3 , preferably
superior to 3.0 g/cm3 and
more preferably comprised between 5.5 g/cm3 and 9.0 g/cm3.
The means for bringing the mixture in contact with at least part of the
surfaces of the plates are
advantageously, spraying means and/or a conveyor.
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Means for bringing the mixture in contact with at least part of the surfaces
of the plates are spray
nozzles that spray the mixture onto the surface of the plates of the charge
when the feedstream is
liquid and/or mixture of liquid and/or gas are particularly suited.
The means for bringing the solids outside the reactor is (are) advantageously
entrainment with
the product gas, scoop(s), screw conveyors and/or gravity.
The means for bringing the solid outside the said reactors comprise an exit
hopper arrangement
attached to the solids exit tube.
According to a preferred embodiments, the rotating reactor has two exits: one
for the solids and
one for the gas/vapours and entrained solids obtained. The gas/vapours
obtained may contain
entrained solids.
The rotating kilns used as constitutive element of the mobile plants of the
invention are equipped
with means for avoiding accumulation of solid in the reactor and/or for
plugging of any of the
exits.
The means for avoiding accumulation are advantageously a screw conveyor in the
solids exit
tube, or a slanted solids exit tube.
According to a preferred embodiment, the reactor is a cylinder, or a cylinder
with two conic
extremities, or two cones attached by their basis, or a sphere. Preferably the
reactor is a heated
cylinder having a length to radius ratio ranging from 1 to 20 and preferably
ranging from 2 to 15,
more preferably this ratio is about 10.
The rotating kilns used in the the mobile plants may comprise a feeding line
positioned about the
longitudinal central axis of the reactor, said feeding line being attached to
the internal walls of
said reactor by attachment means that allow said feeding line to stay immobile
despite the
rotational movement of said reactor. Said attachment means may comprise a tube
and/or at least
a ring surrounding said feeding line, said surrounding tube and/or surrounding
ring(s) being
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attached to the internal wall of the reactor and leaving at least part of the
feeding line not
surrounded. The diameter and/of the constituting material of the surrounding
tube and/or of the
surrounding ring(s) is (are) selected in order to allow the thermal expansion
of said feeding line.
According to a preferred embodiment, said attachment means comprise a second
tube and/or at
least a second ring surrounding said first tube and/or said at least first
ring surrounding said
feeding line, said second surrounding tube and/or said surrounding ring(s)
being attached to the
internal wall of the reactor and to the external surface of said first tube
and/or of said at least first
ring surrounding said feeding line and leaving at least part of the feeding
line not surrounded by
support rings.
The length of the attachment means of the second tube and/or of the at least a
second ring is
advantageously about the distance between the external wall of said the second
tube and/or of
the at least a second ring to the internal wall of the said reactor. Wherein
the length of the
attachment means of the second tube and/or of the at least a second ring may
be superior,
preferably for at least 10 %, more preferably superior for at least 20 %, to
the distance between the
external wall of said the second tube and/or of the at least second ring to
the internal wall of the
said reactor. Alternatively, the length of the attachment means of the said
first tube and/or of the
said at least first ring to the second tube and/or to the at least a second
ring is about the distance
between the external wall of said first tube and/or of said at least first
ring to the internal wall of
the second tube and/or to the at least a second ring. According to another
embodiment, the
length of the attachment means of the said first tube and/or of the said at
least first ring to the
second tube and/or to the at least a second ring is superior, preferably for
at least 10 %, more
preferably for at least 20 % to the distance between the external wall of said
first tube and/ or of
said at least first ring to the internal wall of the second tube and/or to the
at least a second ring.
Some, preferably each, of the attachment means are articulated to their
attachment point.
The reactor is advantageously configured in a way that reactor feed is made
laterally trough one
end of said reactor, and the exists of the vapours obtained during the thermal
processing is
positioned on the same end or at the opposite end of said reactor. The reactor
feed may be made
laterally trough one end of said reactor, and the exists of the cokes obtained
during the thermal
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processing is positioned on the same end or at the opposite end of said
reactor. Alternatively, the
reactor feed is made laterally trough one end of said reactor, and the exists
of the vapours
obtained during the thermal processing is positioned on the same end or at the
opposite end of
said reactor.
According to a preferred embodiment, the mobile plant of the invention are
configured in a way
that the rotating kiln have heating means inside allowing the thermal
processing to occur on the
plates that are heated on the external walls of the kiln.
The shelves may also be attached to the exterior surface of the kiln.
According to another preferred embodiment, the external walls of the kiln face
the internal wall
of the said stationary housing.
The feeding of the mixture may be on the top of the reactor and is thus
preferably at equal
distance of each end of the reactor.
The exit of the vapour may be positioned on a side of the walls of the reactor
and preferably at
equal distance of both ends of said reactor.
The exit of the coke may be positioned on a side of the walls of the reactor
and preferably at equal
distance of both ends of said reactor.
The exit of the solids may be on the bottom of the reactor and preferably is
at equal distance of
each end of the reactor.
The said rotating kiln rotates around its centre axis, the said axis may be
horizontal or slanted.
In the mobile plants of the invention, the first unit advantageously
comprises:
= Means to heat, and possibly filter, the feed stream
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= Means to dehydrate the feed stream and to at least partially condense the
vapours exiting
the dehydrator
= Means to separate the water, light oils and non-condensable gas
= Means to send the non-condensable gasses to fuel
= Means to inject additives, if required
= Means to introduce the hot oil recycle stream
In the first unit the feed stream is preferably a waste oil and the dehydrator
is heated either by
direct contact with the hot heavy oil recycle stream, by an electric heater
mounted in a sleeve in
the dehydrator and/or by a circulating dehydrator bottom oil stream in a heat
exchanger or
heater.
In the mobile plant, Unit II preferably contains:
= Means to further pre-heat the reactor feed stream,
= Means to inject a sweep gas, either into the reactor feed stream or directly
into the reactor,
= Means to feed the reactor feed stream into the reactor,
= A rotating kiln containing plates and operating under pressure,
= Two reactor exits: one for vapours and entrained solids, and one for solids.
In the mobile plant, Unit III preferably contains:
= Means to separate the solids from the vapours exiting the kiln, preferably
heated in a
second enclosure,
= Means to remove residual solids from the vapours exiting the reactor,
= Means to cool, and to partially condense the reactor products,
= Means to separate the reactor products into a specified product slate, and
= Means to cool the liquid products
According to a preferred embodiment, in the mobile plants of the invention
only unit I, or only
unit II or only unit III is mobile.
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According to another preferred embodiment, only units I and II are mobile, or
only units II and III
are mobile.
In the third unit, the means to separate the solids from the vapours exiting
the reactor can be a
stationary box, heated cyclones and/or a self-refluxing condenser. The means
to separate the
reactor products into specification product cuts can be a succession of flash
drums, (a) distillation
column(s) operating under pressure, at atmospheric pressure and/or under
vacuum. The means
of cooling the reactor products are conventional equipment such as heat
exchangers with cooler
oil streams and/or cooling water and/or air coolers.
A second object of the present invention is constituted by the processes for
thermally treating a
feed material by using a mobile plant as defined in the first object of the
present invention.
The processes of the invention are using a mobile plant for thermally treating
a feed stream and
comprises the following steps:
i. a first step wherein the feed stream is heated and/or dehydrated and/or
degased
(Step I);
ii. a second step the heated feed stream is thermally processed (pyrolized)
and the
resulting thermally processed streamed is treated by a vapour solid separator
(Step II);
and
iii. a third step (Step III) that is a product separation step wherein part
that of the treated
feed stream (heavy oil), recovered in Step III may be recycled, into Step I or
II.
Unit I and/or unit II is (are) configured for injecting a sweep gas in said
feed oil and or in said
rotating reactor, and/ or the second unit is configured in a way that the
rotating reactor may work
under positive pressure.
According to a preferred embodiment, in said processes:
- a) said rotating kiln operates under a positive pressure that is
preferably of at least 1 psig
and for producing the following components: coke and non condensable gas
and/or heavy
oils and/or wide range diesel oils and/or naphtha, each of those produced
components
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CA 02757061 2011-10-20
being recovered separately or in the form of mixtures of at least two of these
components,
wherein in said process a sweep gas, that is an inert gas or a substantially
non reactive gas,
is injected into the said rotating kiln or in the said oily feed stream
entering the said
rotating operating kiln; or
- b) said rotating kiln operates under a positive pressure that is preferably
of at least_l psig
and for producing the following components: coke and non condensable gas
and/or heavy
oils and/or wide range diesel oils and/or naphtha, each of those produced
components
being recoverable separately or in the form of mixtures of at least two of
these components;
or
-c) said rotating kiln operates for producing the following components: coke
and non
condensable gas and/or heavy oils and/or wide range diesel oils and/or
naphtha, each of
those produced elements being recoverable separately or in the form of
mixtures of at least
two of these components, and wherein in said process a sweep gas, that is an
inert gas or a
substantially non reactive gas, is injected into the said rotating kiln or in
the feed stream
entering the said rotating operating kiln.
The feed material is advantageously an oily feed that is preferably a
contaminated oil or an
uncontaminated oil.
Among the oily feed is selected among: contaminated or uncontaminated oils,
waste oils, used
lubricating oils, oily tank bottoms, Marpol, heavy oils, bitumen and other
heavy oils, coal, oil
sands, asphalts, chemically pre-treated oils or mixtures of at least two of
the latter, are of a
particular interest.
During the process, the vapours and the solids exiting the rotating kiln in
function may
advantageously be routed to vapour solid decantation means.
According to a preferred embodiment, the vapour solid separation means are a
stationary box
and/or a heated cyclone for the heavier solid and/or cyclone(s) to separate
most of the solids
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present in said vapours exiting the rotating kiln from the said vapours; the
cyclone treatment
following advantageously the treatment by one or several cyclones.
The solids present in said vapours exiting the rotating kiln may be: coke,
metals, sand, dirt,
asphaltens, preasphaltens, sulphurous compounds, heavy polymers such as gums
and/or resin,
salts, cokes containing various compounds such as sulphur, halogen and metal;
each of these
solid component being alone or in mixture with at least one of the latter
component.
The vapour-solid separation equipment, preferably the separation box an or the
cyclones, is (are)
preferably heated, at a temperature that is(are) above the temperature of the
vapours existing the
kiln, preferably this temperature is up to about 300 degrees Celsius, more
preferably up to 200
degrees Celsius, advantageously up to about 20 degrees Celsius, more
preferably up to 10 degrees
over the temperature of the vapours exiting the kiln.
The vapour solid separation equipment, preferably the cyclones and/or the
separation box, are
advantageously heated at a temperature that is at least 10, and preferably at
least 20, degrees
below the cracking temperature of the vapour.
The solid exiting the rotating kiln may be a dry coke, for example this coke
preferably contains
less than 2 weight percent of oil.
According to an advantageous embodiment of the processes of the invention,
most, preferably
more than 50 %, more preferably more than 90 %, of the coke is removed from
the vapours
exiting the rotating kiln, and, in the case wherein the feed oil is an used
oil, up to 99,5 % of the
coke is removed from said vapour exiting the rotating kiln.
The vapours exiting the vapour solid separating equipment, such as cyclone(s),
are
advantageously partially condensed in a self-refluxing condenser and/or in a
wash tower, to
complete the solids removal from the reactor products.
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The vapours exiting the last step wherein solids are advantageously
eliminated, and this step
takes preferably place at the top of the condenser and/or of the wash tower,
are routed to
product separation, while the recovered heavy oil containing the residual
solids exits at the
bottom.
The heavy oil, resulting from the process containing the residual, is recycled
preferably in a
dewatering step, when present, and/or in the oil feed entering at the
beginning of the process,
and/or in the oil feed entering the rotating kiln feed.
The recovered heavy oil and the fractionators bottoms oil positioned in the
product separation
section can also be used as back flushing oils to clean fouled equipment.
The positive pressure, in the rotating kiln, may advantageously ranges from 1
to 4 atmospheres,
preferably this pressure ranges from 1.2 to 1.5 atmospheres.
According to a preferred embodiment, the feed oil, before entering the
rotating operating reactor,
is heated, preferably at a temperature that is at least 20 degrees Celsius
under the cracking
temperature of the feed oil.
The water present is advantageously removed from the feed oil, before the feed
oil enter the
reactor. The water removal is preferably performed in a flash evaporator, from
the feed oil, before
the said feed oil enter the rotating kiln.
The processes of the invention may also be used for the thermal processing of
a feed oil that is an
oil, which according to its history and/or according to its origin, was,
before entering the rotating
kiln, chemically treated, or slightly chemically treated, to reduce its metal
content, preferably the
feed oil is treated by at least one acid and by at least one base, the acid
being advantageously a
sulphur acid and/or a phosphoric acid. The feed oil may also be an oil that
was physically
and/or chemically pre-treated before entering the said the process.
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CA 02757061 2011-10-20i
In the heating step(s), that may be performed in step I and in step lithe
is(are) accomplished in a
heater and/or by heat exchange with a hot oil stream, a hot thermal fluid, by
the injection of a hot
gas, by direct contact with a hotter oil stream, or by a combination of at
least two of these
methods.
According to a preferred embodiment, the reactor feed stream resulting from
the heating of the
feed oil is, before entering said rotating operating reactor, sprayed unto
metal plates in a rotating
kiln that contains metal plates, wherein it is thermally cracked and/or
vaporized.
The reaction products that exit the rotating kiln may comprise hydrocarbon
vapours and other
vapour present in the reaction zone of the rotating operating kiln and solid
coke.
The reaction products exiting the rotating operating kiln are advantageously
swept out of the said
rotating operating reactor as soon as possible, preferably in 5 seconds to 60
minutes, more
preferably in about 5 minutes; the residence time is a function of at least
one of the following
parameters: feed oil composition, the reaction pressure, the temperature
and/or the desired
product slats.
The reaction products, when swept out of the said rotating, are heated
advantageously heated at
a temperature that is advantageously slightly over the temperature at the exit
of the reactor.
According to a preferred embodiment, most of the coke is removed from the
hydrocarbon stream
exiting the rotating kiln, before the oil is condensed preferably in a
vapour/solid separator and
then advantageously in cyclones and/or in a wash tower or in a self reflecting
condenser.
The hydrocarbon product stream is advantageously condensed and separated into
specified
products.
According to preferred embodiments of the processes of the invention:
- at least part, and preferably all, the non-condensable gas produced in
the said rotating
operating kiln is used as fuel on site; or
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- at least part, and preferably all, the naphthas present in the feed oil
and/or produced in
the said rotating kiln is used as fuel on site.
When a sweep gas is used, the sweep gas used is preferably a super heated
steam. The sweep gas
may represent in weight up to 30 % of the weight of the feed oil, preferably
up to 10 %, and
more preferably between 0.5 and 5 % of the weight of the feed oil.
The cyclones used to separate the coke and other solids are advantageously
positioned outside of
said rotating operating reactor but inside a second heated enclosure, said
second kiln
communicating or not with the first reaction's zone in order to benefit of a
warm hot flue gas flow
surrounding said cyclones.
At least part of the purified oils thereby recovered may be used on the site
or sold to clean heat
exchanger(s) or other fault equipments.
The residence time in the rotating kiln ranges from 3 to 15 hours, and this
time preferably range
from 2 minutes and 30 minute.
The demetalisation rate of the total liquid oil products (heavy oil, wide
range diesel and naphtha)
recovered during said process is advantageously of at least 90 %, preferably
of at least 95 % and
more preferably of at least 99 %. The total recovered oil contains less than
60 PPM of metal.
The metals mainly present in the recovered total oil products are mainly
copper, iron and zinc,
the other metals being at a level that may be as low or inferior to 1 PPM.
Chrome, vanadium,
cadmium, nickel and lead, originally present in the feed stream, being during
said process mainly
concentrated in the recovered coke, the concentration may reach up to 99 %
weight.
According to a preferred embodiment, the gas recovered from the rotating kiln
being mainly
composed of hydrocarbon, preferably alkanes and/or of alylenes. The gas and
the naphtha
produced are advantageously used as fuel on the site to satisfy the energy
self sufficiency of the
plant in function.
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The recovered oil is characterized in that is has no sulphurous content or has
less than 3000 ppm
of the sulphur in the mixture.
The processes of the invention allows a limited amount of Marpol may be
injected in the feed oil
that is preferably of the type present in the bottom of ship fuel tank. Said
limited amount of
Marpol may advantageously represent from 10 to 95 % of the weight of the feed
oil and the feed
oil may be replaced by a Marpol (no direct injection).
The limited amount of water present in the oily products represent up to 98 %
weight of the feed
oil, provided the oil is at a temperature lower than its vaporisation
temperature at line pressure
The processes of the invention are particularly suited for treating limited
amount of oily products
containing up to 99 % weight of the feed oil.
The processes of the invention are particularly efficient due to the fact that
said rotating kiln
contains a charge of plates and at least part of the surface of said plates is
used to perform said
thermal treating. Advantageously, the thermal processing is performed on at
least part of the
surface of said plates in movement. Preferably, the processes of the invention
are used for thermal
processing of a mixture, wherein thermal processing is performed on at least 5
%, preferably on at
least 10% of the surface of said plates and/or on at least 5 %, preferably on
at least 10% of the
plates.
It has been surprisingly discovered that during thermal processing of a
mixture, wherein said
plates when moving inside said reactor clean the walls of said reactor, and
avoid reactor wall
failures.
It has been also surprisingly discovered that during thermal processing of a
mixture said plates
protect at least part of the walls of said reactor and that said plates
contribute to the uniformity of
temperatures conditions in said reactor.
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It has been further discovered that during the thermal processing of a mixture
in said plates
contribute to the heat transfer taking place from the heated walls to the
surface of said plates,
particularly to the heat transfer taking place on the surfaces of those plates
wherein thermal
processing occurs.
A third object of the present invention, is constituted by the uses of a
process as defined in the
second object of the present application, for:
- treating wastes oils such as used lubricating oils, form oils, metal
treating oils, refinery or
transportation oil tank bottoms; and/or
- destroying hazardous and/or toxic products; and/or
- reusing waste products in an environmental acceptable form and/or way;
and/or
- cleaning contaminated soils or beaches; and/or
- cleaning tar pit; and/or
- use in coal-oil co-processing; and/or
- recovering oil from oil spills; and/or
- recovering PCB free transformed oils.
The uses of a process of the invention for treating used oils and to prepare:
- a fuel, or a component in a blended fuel, such as a home heating oil, a
low sulphur marine
fuel, a diesel engine fuel, a static diesel engine fuel, power generation
fuel, farm
machinery fuel, off road and on road diesel fuel; and/or
- a cetane index enhancer; and/or
- a drilling mud base oil or component; and/or
- a solvent or component of a solvent; and/or
- a diluent for heavy fuels, bunker or bitumen; and/or
- a light lubricant or component of a lubricating oil; and/or
- a cleaner or a component in oil base cleaners; and/or
- a flotation oil component; and/or
- a wide range diesel; and/or
- a clarified oil; and/or
- a component in asphalt blends,
32
,
CA 02757061 2011-10-20
are also of a particular interest.
A fourth object of the present invention is constituted by the uses of the
products, preferably of
the diesel, and heavy oils, obtained in a process, as defined in the second
object of the invention,
for cleaning fouled equipment such as tank bottoms or other reservoir
contaminated with
hydrocarbons and other fouling materials such as asphaltenes, tars, coke,
salts, dirt, gums, and
resins.
The uses for cleaning equipment and materials contaminated with hydrocarbons
and other
fouling materials such as asphaltenes, tars, coke, salts, dirt, gums, and
resins are of a particular
interest.
According to the uses of the invention, the cleaning of the fouled equipment
is performed
without water and or without a need to separate water from the residue of the
cleaning. Also the
invention permits the use of higher temperatures and the heavy polarized oils
allow for a higher
efficiency for removing fouling materials containing hydrocarbons.
Advantageously, the residue from the cleaning and the oil, thereby obtained,
can then be pumped
out and treated.
A fifth object of the present application is constituted by the use of a
mobile plant, as defined in
the first object of the present application, on the site wherein contaminated
oil is present in
contaminated equipments, to produce heavy polarized oils to clean the
contaminated
(equipments) tanks on the site and equipment and then treat the residue of the
cleaning into
heavy oils to obtain commercial products and more oil to continue the cleaning
process.
Among those uses, those wherein contaminated oil is present in a contaminated
equipment, to
perform effective periodic cleaning of a contaminated equipment such as tank
farms and refinery
equipment, are of a particular interest.
33
CA 02757061 2011-10-201
These uses of a mobile plant, may be performed on the place wherein
contaminated oil is
generated or on a specific place (storage unit) close to other places wherein
various contaminated
oils are generated and with reduced transport of waste oils which are
hazardous material.
The uses of a mobile plant, to treat waste oils in regions with low density of
population, for
example near out of the way mines or industrial complex and where the volumes
of oils to be
treated at any given time is low and the cost of transporting the oils is high
or could lead to
ecological disasters during the transport, are also of a particular interest.
According to a preferred embodiment of the uses of the invention, the waste
oils treated are most
of the waste oils in these regions are burned or thrown away which is very bad
for the
environment.
Also of a particular interest are those uses of a mobile plant wherein said
mobile plant is
transported on a periodic basis and or when necessary, for example in the case
of an irregular
production of contaminated oils or in the case of an accidental environmental
contamination, in
these regions to treat the oils and sell the product in the region.
Advantageously, are the uses of mobile plant of the invention wherein said
mobile plant or at
least one unit, preferably at least unit II, of said mobile plant, is built
within a standard 45 feet
hicube container.
Preferably the mobile plant and is transported by truck, rail, airplane,
submarine or boat.
A sixth object of the present application is constituted by the processes for
manufacturing the
mobile plants as defined in the first object of the present invention, wherein
said process
comprises assembly by known means the constituting elements of said reactor.
Advantageously, in the manufacturing processes, the known assembling means
comprise at least
one of the following means: screwing, jointing, riveting and welding.
34
,
CA 02757061 2011-10-20
Those manufacturing processes, comprises manufacturing steps wherein Unit I
and or Unit II and
or unit III are attached on the platform of a mobile vehicle such as truck,
wagon, plane, ship.
Detailled description of the invention
Figure 1 is a simplified flow diagram illustrating a version of the process.
The waste oil feedstock can contain up to 20% water in an emulsion, and up to
10% naphtha. Free
water should be separated at the tank farm. The feed oil can be chemically pre-
treated before
entering the plant, however, it is usually not required.
The feed oil (1) is filtered (2) and heated to approximately 90 C (3). If
necessary, the waste oil
feedstock may be filtered again or put through a decanter to remove as much
solids (12) as
possible before entering the dewatering unit. The feed oil is sprayed into a
pre-flash drum (4)
where a pool of oil is kept hot by means of a re-boiler heater (5). The water
and naphtha in the
feed oil are evaporated and exit the flash drum from the top of the vessel.
The water and naphtha
are cooled and condensed (6) and the water (7), naphtha (8), and possibly gas
(9) are separated
and pumped to the tank farm. The de-watering system can operate at pressures
up to 90 kPa
gauge, and hot oil temperatures up to 260 C.
The hot and dry oil from the flash drum is heated (10), either through heat
exchange or put into a
vacuum column. It is then routed to the reactor. A gas stream (11),
representing between 0.1%
weight. and 10% weight. of the reactor feed stream, is introduced into the dry
waste oil feed
stream to the reactor. When used lubricating oils are processes, the steam
injection rate should be
around 4% weight. on dry feed. The gas stream serves many functions: It
changes the flow
regimes of the reactor feed stream and prevents fouling and plugging of the
piping and spray
nozzles. It reduces the oil's residence time in the reactor, thereby reducing
the incidence of
secondary reactions, or over-cracking, resulting in more stable product oils.
It can also be part of
the stripping gas stream in the product distillation unit.
35
CA 02757061 2011-10-20
The combined oil and gas stream is introduced into the reactor through one or
more spray
nozzles (14) within the rotating kiln (13) as described in the Canadian Patent
Application
2,704,186. The kiln rotates within a combustion chamber (15) which is fired by
temperature
controlled burners (16). The rotating kiln has internals and is kept at the
desired temperature
such that the vaporization and thermal cracking of the feed oil takes place
before the liquid can
reach the kiln wall. The thermal process produces hydrocarbon vapours and
small solid particles
that contain most of the sulphur, all of the excess carbon, some of the
halides and almost all of the
metals that were in the feed oil.
The reactor operates at a positive pressure up to 90 KPa(g). The kiln
operating temperature is
determined by the quality and quantity of the waste oil, and by the quality
and quantity of the
desired products. It can vary between 380 C and 4600C for used lubricating
oils feeds, and up to
550 C, when bitumen or heavy oils are treated.
The hydrocarbon vapours and the coke particles exit the reactor and enter a
box and/or cyclone
(16) separators where the solid particles are removed from the hydrocarbon
vapours. In a
preferred mode, the vapour-solids separators are in a heated chamber (18) or
heat traced to
prevent dew point condensation and plugging of the equipment. The coke (31)
and other solids
drop by centrifugal force and gravity, cooled (30) and stored. The coke and
other solids exiting
the reactor are non-leachable.
The hydrocarbon vapours enter a flash drum (19) and self-refluxing condenser,
or scrubbing
tower (20) assembly, where any remaining coke is removed. The heavy oil from
the bottom of the
flash drum is recycled to the reactor feed or mixed with the distillation
column bottoms. The
vapours from the reactor are partially cooled (21) and enter the product
separation unit (21). The
vapours exiting the top of the main distillation column are cooled (22) are
the product gas (23),
naphtha (24) and water (25) are separated.
The water is sent to storage or to the water treatment unit. After treatment,
it can be re-used in
the steam generation unit. Some of the naphtha is used as reflux to the main
distillation column,
36
CA 02757061 2011-10-20
the rest is sent to storage. It will later be used as fuel in the plant. The
gas is consumed on site as
fuel in the plant.
The diesel fraction (27) is pulled as a side cut, through a stripper, cooled
(26) and sent to storage.
The column bottoms or heavy product (28) can either be recycled to the
cracking vessel, or cooled
and sold as de-metalized, low sulphur, heavy fuel oil. When heated the heavy
oil is very effective
as backwash oil in the plant. It permits on-stream cleaning of fouled
equipment and minimises
the need for chemical pre-treatment of used oil feeds.
Although the present invention has been described with the aid of specific
embodiments, it
should be understood that several variations and modifications may be grafted
onto said
embodiments and that the present invention encompasses such modifications,
usages or
adaptations of the present invention that will become known or conventional
within the field of
activity to which the present invention pertains, and which may be applied to
the essential
elements mentioned above.
DETAILLED DESCRIPTION OF ROTATING KILN THAT MAY ADVANTAGEOUSLY BE
USED IN THE MOBILE PLANT OF THE INVENTION
Preferred embodiments of the reactor
The invention is that of the indirectly fired rotating kiln (1), represented
on Figures 1 and 2,
having preferably the following dimensions 5' by 20' containing a charge of
700 metal plates (2)
that are lifted by one or more narrow shelves (3) as the reactor rotates at a
speed comprised
between 1 and 3rpm. The shelves are wide enough to hold two plates: one
against the wall, and a
second one against the first plate. The plates are flat pieces of metal of
regular shapes. The heat (5)
coming through the reactor wall heats the plates as they are dragged and
lifted against the reactor
wall by one or more narrow shelves. As the rotation continues, the plates fall
off the shelves or off
the plates below them, and flip as they fall, presenting the hot surface to
the oil jet (4) projected
unto the plates (5) by a Nozzle preferably spraying the oil in a rectangular
pattern.
37
CA 02757061 2011-10-20
The plates carry the heat from the reactor walls and provide a hot surface
where the reactions
take place. The plates are lifted and kept against the reactor walls by
shelves (3). Depending on
the thickness of the plates, the shelves can be designed to hold one, two or
more rows of plates.
As the kiln rotates, the plates fall off the shelves or off the plates below,
presenting the face that
was against the reactor wall to the oil spray.
As they slide over each other, the metal plates become a surface that protects
the reactor walls
from direct contact with the relatively cold oil spray and from the resulting
thermal shock. Also,
as they slide down the reactor, the plates scrape the reactor walls and each
other clean of coke
and avoid bridging of the depositing coke. The coke released is entrained out
of the reactor with
the hydrocarbon gas or is removed by the scoops, hopper and solids exit.
The shelves are attached to the reactor walls with clamps (6), represented on
Figures 4 and 5, to
reduce stress due to the differential thermal expansion between the reactor
walls and the shelves.
The clamps are spaced in such a way that, even at the hottest reactor
temperature, the shelves are
strong enough to support the hot plates on them. Depending on the spacing
between the shelves,
there may be only one double row of plates per shelf or several rows one on
top of each other.
Both the plates and shelves increase the heat transfer area from the heat
source to the reaction
site.
The clamps (6) are shaped like a T as represented in Figures 4 and 5. The base
of the T (7) is
welded to the rotating kiln walls. The cross bar or top of the T (8) is U
shaped to receive the
shelve (3) ends, leaving room for the thermal expansion of the shelves, both
longitudinally and
perpendicular to the reactor wall. Bolts (9) close off the U brackets and keep
the shelves from
falling out of the brackets. The branches of top of the T (6) are wide enough
to allow for the
thermal expansion of the shelves within them, while providing strength and
support for the load
of 1, 2 or more layers of the metal plates along the full length of the
shelves in the reactor, and as
many rows as the spacing between the shelves will accommodate.
Scoops (10) are attached to the kiln wall at the exit end of the kiln to
remove heavier coke that
may have deposited on the bottom of the kiln. The scoops are pipe sections
with one end closed,
and the other end cut on a slant, to allow any hydrocarbon vapours to escape
before the coke falls
into the hopper (11). The scoops are sized small enough so that the metal
plates cannot enter with
38
CA 02757061 2011-10-20
the coke. As the reactor rotates, the scoops turn upside down and dump their
load of coke into a
hopper mounted on the solids exit tube (12). To ensure that none of the plates
block the coke exit
from the reactor, the hopper has a metal grid (13) that will deflect any plate
towards the bottom of
the kiln. The solids exit tube (12) has a screw conveyor (15) to push the coke
out of the reactor.
The solids exit tube can be above the vapour exit tube (14), within the vapour
exit tube, below the
vapour exit, or even at separate ends. There must be at least two exits from
the kiln to ensure that
the reactor exit is never obstructed. In normal operation, the coke will exit
the reactor mostly
through the vapour exit (14). The scoops are required when the feed to the
kiln is interrupted and
there are no vapours to carry the coke out, or when there is a surplus of
coke, or the coke is wet or
heavy.
The reactor is an indirectly fired rotating kiln, heated by the burner 5, and
containing a charge of
metal plates that carry the heat from the reactor walls and provide a hot
surface where the
reactions take place. The plates are lifted and kept against the reactor walls
by one or more
shelves, wide enough to hold two plates. As the kiln rotates, the plates fall
off the shelves,
presenting the face that was against the reactor wall to the oil spray. The
metal plates protect the
reactor walls from thermal shock, and scrape the walls and each other clean of
coke. The shelves
are attached to the reactor walls with clamps to reduce stress due to
differential thermal
expansion between the reactor walls and the shelves. Both the plates and
shelves increase the heat
transfer area from the heat source to the reaction site.
In the test apparatus, used lubricating oils or other oils from a collection
depot are sprayed into a
horizontal or slanted rotating kiln 10' in diameter and 8' long in order to
thermally crack and
vaporize the oil or the chemicals within it. The kiln has 4" fins welded in
continuous spirals, 8"
apart, to the inside of the kiln walls. A 1" wide shelf is attached to the
fins, and a charge of 4"
equilateral triangular metal plates is added.
As the kiln rotates, the shelf pushes and raises the blades along the reactor
wall. As they reach
just past the 5' height, they flip as they fall at the top of their run,
presenting their hot side to the
oil being sprayed on them.
Upon contact with the hot plates, the oil is thermally cracked and/or
vaporized. The coke formed
is either entrained with the vapours out of the kiln or it deposits on the
plates. The plates, sliding39
CA 02757061 2011-10-20
against the reactor wall or on each other, scrape the coke free, and it is
entrained out of the reactor
with the vapours. Most of the coke exits the reactor with the hydrocarbon
vapours; the residual
coke is removed by the scoops, hopper and solids exit.
Four scoops are welded to the reactor wall at the exit end. They are made from
4" piping, 6" long,
with one end plugged, and the other end cut on a slant. A hopper protected by
a metal cage
above it, receives the coke dumped by the scoops. The cage deflects any
scooped up plate back
into the reactor. The hopper receives the coke and drops it into the coke exit
tube. A screw
conveyor, on the bottom of the coke exit tube, carries the coke out of the
reactor.
When the reactor feed is used lubricating oil, the recovered gas is 5% weight
of the feed and has
an average molecular weight of 42, the recovered liquid is 92% weight of the
feed and has an
average specific gravity of 0.83 and the solids are 3% weight of the feed and
have a specific
gravity of 1.7. These numbers depend on the feedstock composition, and on the
reaction
temperatures and pressures.
Figures 7, 9, 11 and 12 are illustrations of the apparatus adapted for
different feedstocks.
Figure 7 shows a vertical cross section of a reactor in the horizontal
position. The reactor actually
has four shelves, but only two are shown here (20). The other two shelves
would be on the section
not shown. The feed enters the reactor in pipe 21, and is projected unto the
hot plates (23) by
spray nozzles (22). A possible feed for this reactor would be an organic
liquid such as waste oils.
The plates are lifted from the plate bed (24) by the shelves (20). In this
illustration, the reactor (25)
is supported by two horizontal cylinders (26) and is heated externally with
gas or naphtha
burners (27). The reactor rotates inside a heating chamber, which is
stationary (38). There are
various options for the heating chamber. It could be a section of a hot stack,
where the stack gas
needs to be cooled before clean-up, for example. A seal (37) is shown around
the rotating kiln and
the stationary wall of the heating chamber. It is useful to keep the feed pipe
in place with support
rings (28), as illustrated on Figure 8. The gas and entrained coke leave the
reactor through the gas
exit pipe (29). Accumulated solid coke is scooped up by shovels (30), is
dumped into a hopper
(31), and is carried out of the reactor with the help of a screw conveyor (32)
inside the solids exit
pipe (33). There is a seal (34) between the rotating reactor and the product
exit box (35). The
40
CA 02757061 2011-10-20
product exit box is stationary. A first separation of solids and vapours
occurs in the product exit
box (35).
Figures 8A and 8B are two cases of center ring supports for the feed line
(39), shown when the
reactor is cool. Figure 8C is the support rings in Figure 8B when the reactor
is hot. Figure A is for
a smaller reactor radius with only one centre ring (40). Figure 8B is for a
larger reactor radius, for
which two centre rings (40) and (41) are required to avoid deforming the
support legs (42). In
Figures 8B and C there are two sets of support legs: The first (42) hold the
larger centre ring (41)
in place. The second set of support legs hold the smaller centre ring (40) in
place. The smaller
centre ring supports the reactor feed pipe (39). The support legs (42) and
(43) are attached to the
reactor wall (45) and/or centre rings with brackets (44) that permit and/ or
allow the support
beams to expand and rotate at their junction points with the reactor walls and
rings.
Figure 9 shows a vertical cross section of a reactor in the slanted position,
about 50 from the
horizontal in this illustration. This reactor would be used for feedstocks
that contain solids such
as sand. The reactor actually has four shelves, but only two are shown here
(20). The other two
shelves would be on the section not shown. The feed enters the reactor in pipe
21, it is pushed
along the feed line with a screw conveyor and is projected unto the hot plates
(23) by nozzles,
holes and/or slits (22). The plates (23) are rectangular and are about as long
as the reactor section
where they are installed. The plates are lifted from the plate bed (24) by the
shelves (20). In this
illustration, the reactor (25) is supported by two slanted cylinders (26) and
is heated externally
with gas or naphtha burners (27). The reactor rotates inside a heating
chamber, which is
stationary (38). A seal (37) is shown around the rotating kiln and the
stationary wall of the heating
chamber. The gas and entrained coke leave the reactor through the gas exit
pipe (29). The solids
that are too heavy to be entrained out of the reactor by the gas, slide long
the reactor floor,
through the screen (36), and are scooped up by the scoops (30). Accumulated
solids are scooped
up, along with residual coke, by shovels (30), are dumped into a hopper (31),
and are carried out
of the reactor with the help of a screw conveyor (32) inside the solids exit
pipe (33). There is a seal
(34) between the rotating reactor and the product exit box (35). The product
exit box is stationary.
A first separation of solids and vapours occurs in the product exit box (35).
41
CA 02757061 2011-10-20
Figure 10 shows two possible configurations for the screens (36) in figures 7
and 9. Figure 10A is a
screen made of wire mesh. Figure 10B is a screen made of a perforated disc.
Both screens are
tacked on to the reactor wall. Their outer circumferences are scalloped,
allowing for different
thermal expansions of the reactor walls and the screens with minimal stress on
the reactor walls.
Both configurations permit both the vapours and the solids to travel
practically unimpeded from
one end of the reactor to the other. The perforations are calculated so as to
avoid movement of the
plates from one section to the other. Also, the perforations must be too small
for the ends of the
plates to enter. The screens will be scraped clean by the plates, as the
reactor turns.
Figure 11 is a vertical cross section of a reactor in the slanted position,
about 50 from the
horizontal is illustrated here.
This reactor would be used for feedstocks that contain solids such as sand.
The reactor actually has four shelves, but only two are shown here (20). The
other two shelves
would be on the section not shown. The feed enters the reactor in pipe 21, it
is pushed along the
feed line with a screw conveyor and is projected unto the hot plates (23)
through the end of the
pipe or slits in the pipe (22).
The plates (23) are rectangular and are about as long as the reactor section
where they are
installed when the reactor is heated. The plates are lifted from the plate bed
(24) by the shelves
(20). In this illustration, the reactor (25) is supported by two slanted
cylinders (26) and is heated
externally with gas or naphtha burners (27). The reactor rotates inside a
heating chamber, which
is stationary (38). A seal (37) is shown around the rotating kiln and the
stationary wall of the
heating chamber. The gas and entrained coke leave the reactor through the gas
exit pipe (29). The
solids that are too heavy to be entrained out of the reactor by the gas, slide
long the reactor floor,
through the screens (36), and are scooped up by the scoops (30). Accumulated
solids are scooped
up, along with residual coke, by shovels (30), are dumped into a hopper (31),
and are carried out
of the reactor with the help of a screw conveyor (32) inside the solids exit
pipe (33). There is a seal
(34) between the rotating reactor and the product exit box (35).
The product exit box is stationary. A first separation of solids and vapours
occurs in the product
exit box (35).
42
i
CA 02757061 2011-10-20
Figure 13shows a vertical cross section of a reactor made up of two cones
joined at the base.
This reactor could be used for liquid feedstocks and/or feedstocks that
contain solids such as
sand. The reactor actually has four shelves, but only two are shown here (20).
The other two
shelves would be on the section not shown. The feed enters the reactor in pipe
21, and is projected
unto the hot plates (23) through the end of the pipe or spray nozzles (22).
The plates (23) are rectangular and are about as long as the reactor section
where they are
installed when the reactor is heated. The plates are lifted from the plate bed
(24) by the shelves
(20). In this illustration, the reactor (25) is supported by two truncated
cones and a cylinder (26)
and is heated externally with gas or naphtha burners (27). The reactor rotates
inside a heating
chamber, which is stationary (38). A seal (37) is shown around the rotating
kiln and the stationary
wall of the heating chamber. The gas and entrained coke leave the reactor
through the gas exit
pipe (29). The solids that are too heavy to be entrained out of the reactor by
the gas, slide long the
reactor floor, and are scooped up by the scoops (30). Accumulated solids are
scooped up, along
with residual coke, by shovels (30), are dumped into a hopper (31), and are
carried out of the
reactor with the help of a screw conveyor (32) inside the solids exit pipe
(33).
There is a seal (34) between the rotating reactor and the product exit box
(35). The product exit
box is stationary. A first separation of solids and vapours occurs in the
product exit box (35). This
shape of reactor allows the plates to slide back towards the entrance and
scrape the walls, other
plates and the shelves clean of coke and other deposited solids.
Figure 14 represents a vertical cross section of a reactor in the slanted
position, about 5o from the
horizontal is illustrated here. This reactor would be used for heavy oils
feedstocks that may
produce more coke or contain sand or contaminated soils.
The reactor actually has four shelves, but only two are shown here (20). The
other two shelves
would be on the section not shown. The feed enters the reactor in pipe 21, it
is either pumped or
pushed along the feed line with a screw conveyor and is projected unto the hot
plates (23)
through spray nozzles or slits in the pipe (22). The plates (23) are
rectangular and they not only
flip when falling off the shelves, but also slide along the shelves, scraping
coke off the shelves and
reactor walls.
43
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CA 02757061 2011-10-20
The plates are lifted from the plate bed (24) by the shelves (20). In this
illustration, the reactor (25)
is supported by two slanted rollers (26) and is heated externally with gas or
naphtha burners (27).
The reactor rotates inside a heating chamber, which is stationary (38). A seal
(37) is shown around
the rotating kiln and the stationary wall of the heating chamber. The gas and
entrained coke leave
the reactor through the gas exit pipe (29). The solids that are too heavy to
be entrained out of the
reactor by the gas, slide long the reactor floor, and are scooped up by the
scoops (30).
Accumulated solids are scooped up, along with residual coke, by shovels (30),
are dumped into a
hopper (31), and slide out of the reactor through the slanted solids exit pipe
(33). There is a seal
(34) between the rotating reactor and the product exit box (35). The product
exit box is stationary.
A first separation of solids and vapours occurs in the product exit box (35).
DESCRIPTION OF THE MOBILE PLANT
This example of a mobile thermal cracking plant can process 50 barrels per
stream day (BPSD) of
used lubricating oil or heavy fuel left as a tank bottom. All the essential
equipment is mounted in
a container, or on a flat-bed truck, or on the bridge of a ship.
Figure 15 is a simplified flow sheet of the process.
The waste oil feedstock (1) is pumped with P-101, to stream (2), the feed to V-
102, the dehydrator.
P-103 pumps dehydrator bottom oil (3) through H-104. The oil exiting H-104 is
separated into
two streams, one (stream 4) returning to V-102, providing the heat required to
vaporise the water
in the feed oil, and the second stream (5) is the reactor feed oil.
Water, stream (6) is heated, becomes steam (7) and injected into stream (5).
The combined stream
(8) is injected into the reactor (R-120), where the oil is thermally cracked
and/or vaporized. The
vapours and coke exiting the reactor, stream (9), are routed to one or more
heated cyclone(s), Cy-
121, where the coke drops out in stream (10), and the vapours, stream (11),
are sent to a
dephlegmator (AC-124). The heavy oil, containing traces of coke is pumped with
P-123 out of V-
122, in stream (12). The vapours exiting the dephlegmator (13) are routed to a
column pre-flash
drum, V-130.
44
CA 02757061 2011-10-201
The liquid from the pre-flash drum, stream enters the column, C-131, a few
trays, maybe 4 trays,
from the bottom, while the vapours from V-130, stream (15), enters the column
below the bottom
tray, and provides the vapour flow to the column.
The column overhead vapours, stream (21), are routed to an air cooler, AC-134,
in which the
naphtha cut and the steam are condensed. Stream (22), containing water and
liquid naphtha
along with non-condensable gas enter V-135, a three phase separator. The non-
condensable gas,
stream (23), serves as fuel in the plant.
The naphtha, stream (24), is pumped out of V-135 with P-138. It separates into
two streams:
stream (25) is the reflux to the column, providing the liquid flow in the top
section of the column,
while stream (26) is product naphtha sent to storage and/or serves as fuel in
the pant.
P-137 pumps the water (or condensed steam) to a treatment facility or to
storage, stream (27).
Figure 16 illustrates how all the equipment in figure 1 can be transported on
a flatbed truck, or
inside a container.
The column, C-131, is transported in the horizontal position, sitting on three
supports: Si, S2, and
S3. The supports are 6 feet high and have a semi-circular shape at the top to
hold the column in
place. Support Si is the pivot around which the column can be raised and
lowered. Si also
serves as part of the column's skirt, when the column is vertical.
The pumps are on pallets and are put either on the back end of the flatbed or
under the column.
The rest of the space under the column is a storage area for the piping that
is removed for
transport, and will be hooked-up when the plant is on site.
45
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CA 02757061 2011-10-20 i
The air coolers are on a rack above the two three phase accumulators, V-135
and V-106. The air
coolers are on supports and rails, and can slide out once the plant is on
site.
A heat exchanger, E-109, is not shown on the simplified flow diagram. It cools
the vapours
exiting the dephlegmator and heats the reactor feed stream, reducing the heat
required in the
reactor R-120.
Figure 17 is a plot plan showing the equipment once deployed on site.
A second flatbed or container truck would carry the control room and
instrument switch boards,
along with an enclosed flair and a fork lift truck. The flare would be
installed at a safe distance
from the plant once on site.
ADVANTAGES OF THE USE OF A ROTATING KILN
In order to understand the advantages of the invention, it may be useful to
explain why the
invention was necessary and how it progressed.
In the kiln above, at first, the oil was sprayed on a charge of ceramic balls.
For the reaction to
occur, the kiln had to be over heated because the charge impeded heat transfer
to the reaction
sites. Furthermore, the ceramic balls were too smooth and light to scrape the
coke off the reactor
walls. The balls exploded into dust because of the thermal shock between the
cold oil and the hot
reactor wall. The reactor had to be shut down to remove the coke and ceramic
dust that caked the
reactor wall and bottom. The reactor runs were less than a day long.
The solids charge was changed to a number of coarse granulated solids charges.
They were more
effective in scraping the coke off the reactor walls but soon the coke stayed
trapped within the
charge, again impeding the heat transfer to the reactor sites. The temperature
at the reaction site
varied as the coke built up within the charge. The run times increased to 3 to
4 days before the
reactor had to be shut-down.
The solids charge was replaced by off-spec cultivator blades : equilateral
triangles, with 6" sides,
made of carbon steel. The blades were effective in keeping the reactor walls
clean but the
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CA 02757061 2011-10-20
temperature in the reactor continued to vary. A shelf was attached to the
reactor wall and the
reaction temperature became steady and easier to control, allowing for a
specific slate of products
of consistent qualities. The reactor walls stayed free of coke and run times
increased to 6 weeks or
more.
Thermal cracking is an endothermic reaction. Since the oil spray was directed
to the hot metals
plates, the coke deposited on the metal plates instead of the reactor walls.
The blades not only
removed the coke that formed on the reactor wall, they protected the reactor
wall from coke
depositing there in the first place. The shelf pushed the metal plates higher
and longer against the
reactor wall. The reaction surface area and its temperature could be increased
without over firing
the kiln.
There was a conveyor to transport the coke from the bottom of the reactor to
the exit tube. The
conveyor was enclosed, protecting the coke and hydrocarbon vapours from the
heat source. This
caused the coke to be wetted by the condensing oil, and to agglomerate. This
apparatus resulted
in the formation of coke-oil plugs that obstructed the exit tube and cause
over pressuring of the
reactor. The enclosed conveyor was replaced with scoops, open to the kiln
heat, dumping dry
coke into the new coke exit tube. The coke exit tube was separated from the
vapour exit to avoid
re-entrainment of the fines into the product vapours or plugging of the only
exit from the reactor
and over-pressurizing the reactor.
EXAMPLES - Mobile plant for thermally treating a feed oil, that is a
contaminated oil Ces
exemples se rappportent-ils plus precisement au mobile plant ou peuvent-ils
etre adaptes au
cas du mobile plant
The mobile plant represented on Figure 15, has a day capacity of 50 barrels
per day (BPD) for
thermally treating waste oils, and making useful products without
environmentally harmful by-
products.
The mobile plant comprises and a rotating reactor having the following
specifications:
= Reactor cylinder internal diameter: 5'
= Reactor cylinder length: 20'
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CA 02757061 2011-10-20
= Heat released: 0.5 MMBtu/hr
= Conic section heights: 2.5'
= Housing external size: 7' high 6' wide and 26' long
Examples 1, 2 and 3 were tests performed using dry waste oil drawn from the
same drums to
eliminate test result differences due to variations in feed oil quality as
much as possible.
Example 1 was performed with the injection of 5% weight. water added to the
161/h reactor feed
oil.
Example 2 kept the same oil feed rate and operating conditions as in example 1
but without water
injection into the reactor.
In example 3, the oil feed rate was increased by 50% to 24 1/h, again without
water in the reactor
feed.
Example 4 was performed on the same kiln but with a different oil sample.
Example 1:
Refer to Table 1 - Example 1 for a summary of the operating conditions and
feed and products
rates and analyses. The waste oil streams tested contained used lubricating
oils as well as other
oily streams such as metal working oils, transmission fluids, greases, form
oils, and any number
of unknown waste oil streams.
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CA 02757061 2011-10-20
TABLE 1 -EXAMPLE 1
Reactor Size: L = LO7 m, Diameter 0.47 m
Reactor Temperature: 490 C
Reactor Pressure: 124 KPa(a)
Sweep Gas: Steam @5% Weight on Feed
Heavy Oil Recycle: None
Oil Feed Rate: 16 L/h
Test Method Units Feed Oil Gas Naphtha Gasoil
Heavy Oil Coke
& Solids
Weight % on Dry Oil Feed 100 5.3 8.0
56.5 20.6 9.6
Density @ 15C ASTM D4052 g/ml 0.89 0.758
0.866 0.933 1.4
Molecular Weight g/mole 36.7
Water (1) .STM D1533 Volume % 5.7 0.7
Metals Digestion & ICP-IS ppm Weight 2160
3 240 25550
Sulphur LECO S32 Weight % 0.63 0.0037 0.05
0.26 0.91 2.63
Halogens Oxygen Bomb Combustion ppm Weight 470 192
84.3 5 219
Viscosity @ 40C ASTM D445 cSt 33.6
2.11 77.1
Copper Strip Corrosion ASTM D120
la
Sediments ASTM 02276 mg/ml
0.5 0.05
Flash Point ASTM D92 C 128
48 <100
CCR D189 Weight % 3.34
1.01
Ash ASTM D4422 &ASTIVI D482 Weight % 0.4
0.01 0.05 7.43
pH
Distillation ASTM D2887 Weight %
IBP C 162 30 110
338
10% C 246 47 156
374
50% C 414 98 255
436
90% C 528 133 355
525
EP C 592 157 419
589
Notes: (1) The oil feed is 95% of the reactor feed stream, while
the water entering the kiln makes up the other
The steam injected into the reactor feed stream is condensed in the
distillation column overhead conde
All the product yields are calculated on a dry oil basis.
A dewatered waste oil stream of 16 L/ min is injected in an indirectly fired
rotating kiln,
containing metal shavings at 490 C reactor exit temperature.
The seals on the kiln were changed to permit pressures above atmospheric in
the reaction zone.
Steam was also injected into the reactor at the rate of 5% weight on dry oil
feed.
As shown on Table 6, a 72% conversion of the 3500C+ fraction into lighter
oils, gas and coke was
observed. Over 95% of the metals entering the reactor exits with the coke.
Example 2:
Please refer to the Table 2, Example 2 for a summary of the operating
conditions and feed and
products rates and analyses.
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CA 02757061 2011-10-20
Table 2- Example 2
Reactor Size: I = 1.07 m, Diameter 0.47 m
Reactor Temperature: 500 C
Reactor Pressure: 125KPa(a)
Sweep Gas: None
Heavy Oil Recycle: None
Oil Feed Rate: 16 L/h
Test Method Units Feed Oil Gas Naphtha Gasoil
Heavy Oil Coke
& Solids
Weight % on Dry Oil Feed 100 9.8 11.2
46.8 22.6 9.6
Density @ 15C ASTM D4052 g/m1 0.893 0.758
0.865 0.933 1.4
Molecular Weight g/mole 37.4
Water STM 01533 Volume % 0.7
Metals Digestion & ICP-IS ppm Weight 2160
3 Not Done 25510
Sulphur LECO S32 Weight % 0.63 Not Done 0.05
0.26 0.91 2.63
Halogens Oxygen Bomb Combustion ppm Weight 470 192
85 5 219
Viscosity @ 40C ASTM D445 cSt 33.6
2.1 77.1
Copper Strip Corrosion ASTM D120
la
Sediments ASTM 02276 mg/ml
0.5 0.05
Flash Point ASTM 092 C 128 <0
48
CCR ASTM 0189 Weight % 3.34
1.01
Ash ASTM 04422 & ASTM 0482 Weight % 0.4
0.01 0.05 7.43
pH
Distillation ASTM D2887 Weight %
IBP C 162 30 150
338
10% C 246 47 178
374
50% C 414 98 255
436
90% C 528 133 343
525
EP C 592 157
589
The waste oil streams tested contained used lubricating oils as well as other
oily streams such as
metal working oils, transmission fluids, greases, form oils, and any number of
unknown waste oil
streams.
A dewatered waste oil stream of 16 L/h is injected in an indirectly fired
rotating kiln, containing
metal shavings at 4900C. This stream was drawn from the same barrel as in
Example 1. The seals
on the kiln had been changed to permit pressures above atmospheric in the
reaction zone. There
was no steam injection into the reactor for this test.
As shown on Table 5, a 69% conversion of the 350 C fraction into lighter oils,
gas and coke was
observed. Over 95% of the metals entering the reactor exits with the coke.
The main difference between these two examples is in the gasoil make: in
example 1, the gasoil in
the products was 56.5% weight, a gain of 30.5% weight on feed oil. In example
2, the gasoil make
was 46.8% weight of the products, a gain of only 20.8% weight on feed oil. The
injection of steam
into the reactor may have impeded the secondary reactions in which the gasoil
present in the
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CA 02757061 2011-10-20
reactor is cracked, producing naphtha and gas. The operation of the reactor
during example 1
was more stable than for example 2 in that temperatures and pressure swings
were calmed. The
wide range diesel oil produced was lighter in colour and more stable in
example 1 than example
2.
Example 3:
Please refer to the Table 3 - Example 3 for a summary of the operating
conditions and feed and
products rates and analyses.
Table 3- Example 3
Reactor Size: L = 1.07 m, Diameter 0.47 m
Reactor Temperature: 495 C
Reactor Pressure: 125KPa(a)
Sweep Gas: None
Heavy Oil Recycle: None
Oil Feed Rate: 241/h
Test Method Units Feed Oil Gas Naphtha Gasoil
Heavy Oil Coke
& Solids
Weight % on Dry Oil Feed 100 0.6 11.9
54 29 4.5
Density @ 15C ASTM D4052 g/ml 0.889 0.752
0.862 0.931 9.0
Molecular Weight g/mole 37.6
Water STM D1533 Volume % 0.7
Metals Digestion & ICP-IS ppm Weight 86.9
0.04 61 (1)
Sulphur LECO S32 Weight % 0.63 0.03
0.26 0.88 2.63
Halogens Oxygen Bomb Combustion ppm Weight 470 190
84.5 45.2 219
Viscosity @ 40C ASTM D445 cSt 33.6
1.89 66.3
Copper Strip Corrosion ASTM D120
3b
Sediments ASTM D2276 mg/ml 0.14
0.6 0.05
Flash Point ASTM D92 C 128 <0
41 222 (OC)
CCR 0189 Weight % 3.34
0.87
Ash ASTM D4422 & ASTM D482 Weight % 0.4
0.05 7.43
PH 4.32
Distillation ASTM D2887 Weight %
IBP C 162 30 144
338
10% C 246 45 172
368
50% C 414 94 251
431
90% C 528 126 335
518
EP C 592 146 400
588
Note: (1) Metals in the coke was not done. The ash at 7.43% wt.
is mostly composed of the metals in the coke
The waste oil streams tested contained used lubricating oils as well as other
oily streams such as
metal working oils, transmission fluids, greases, form oils, and any number of
unknown waste oil
streams. The oil in this test was taken from the same drums as for examples 1
and 2. However,
the analytical data differs a little from the previous examples. This confirms
that waste oil
feedstocks can change in properties, even when pulled from a single tank.
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A dewatered waste oil stream of 24 L/h is injected in an indirectly fired
rotating kiln, containing
metal shavings at 4900C. The seals on the kiln were changed to permit
pressures above
atmospheric in the reaction zone. There was no steam injection during this
test.
As shown on Table 6, a 61% conversion of the 3500C+ fraction into lighter
oils, gas and coke was
observed. Over 95% of the metals entering the reactor exits with the coke.
In this example, the feed rate was increased by 50% over the first two
examples, and there was no
steam injection. Although the conversion of heavy oil is lower than in the
first two examples, 61%
of the 3500C+ oil was cracked, the gasoil gain was 28% weight, higher than for
example 2, and
slightly lower than in example 1. See Table 6. Increasing the feed rate by 50%
also reduced the
secondary reactions but operation of the reactor was difficult because of
pressure swings and
decreasing temperatures in the steal chip bed.
Example 4:
Please refer to the Table 4 - Example 4 for a summary of the operating
conditions and feed and
products rates and analyses.
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CA 02757061 2011-10-20
Table 4- Example 4
Reactor Size: L = L07 m, Diameter 0.47 m
Reactor Temperature: 500 C
Reactor Pressure: 1251(Pa(a)
Sweep Gas: Steam @0.5% wt on dry oil feed
Heavy Oil Recycle: None
011 Feed Rate: 6.7 1./hr
Test Method
Units Feed Oil Gas Naphtha Gasoil
Heavy Oil Coke
& Solids
Weight % on Dry Oil Feed
100 3
9 70 17 1
.Density 15C ASTM 04052
g/ml 0.88
0.841 0.889 1.109 2.683
Molecular Weight
g/mole 37
Water STIV1 01533
Volume % 0.53
Metals (1) Digestion & ICP-IS
ppm Weight 92.3
0 0 81.6 78540
Sulphur LECO S32
Weight % 0.33
0.063 0.15 0.5 1.97
Halogens Oxygen Bomb Combustion ppm
Weight 367
78 75 199
Viscosity @ 40C ASTM 0445
cSt 45.3
1.276
Copper Strip Corrosion ASTM 0120
Sediments ASTM D2276
mg/ml 0.25
Flash Point ASTM 092
C 91
<7 32.5 220
MCRT ASTM D4530
Weight % 1.25
0.13
Ash ASTM D4422 & ASTM D482 Weight %
0.61
0 0.02 68.64
PH
Distillation IBP ASTM D2887
Weight %C 151
25 78 314
10%
C 326.6 78
138 355
50%
C 429 80
209 442
90%
C 558 135
315 612
EP
C 750
397
Notes: (1) Metals in this table
include only Cadnium, Chrome, Copper, Iron, Nickel, Lead, and Vanadium
The waste oil streams tested contained used lubricating oils as well as other
oily streams such as
metal working oils, transmission fluids, greases, form oils, and any number of
unknown waste oil
streams. This oil was heavier than the feed oil in the previous three
examples.
A dewatered waste oil stream of 6.7 L/h is injected in an indirectly fired
rotating kiln, containing
metal shavings at 490 C. The seals on the kiln were changed to permit
pressures above
atmospheric in the reaction zone. Steam was also injected into the reactor at
the rate of 0.5%
weight on feed.
As shown on Table 6, a 79.5% conversion of the 3500C+ fraction into lighter
oils, gas and coke was
achieved. The gasoil make was 70% weight., an increase of 57% of the feed oil.
Over 95% of the
metals entering the reactor exits with the coke.
Please refer to the Table 5 for a summary of the heavy oil conversion and
gasoil product gains in
the four test previously descrived.
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CA 02757061 2011-10-20
Table 5
Heavy Oil Conversion and Gasoil Gain
Example 1 2 3 4
Heavy Oil ¨ 350 C+
% weight in Feed oil 74 74 73 83
% weight in Products 20.6 22.6 29 17
% Converted 72.2 69.5 61 79.5
Gasoil ¨ 185C to 350 C
% weight in Feed oil 26 26 26 12
% weight in the Products 56.5 46.8 54 51.7
% weight Gain on feed oil 30.5 20.8 28 39.7
These examples show that the injection of a sweep gas, in this case steam,
results in a more
efficient conversion of the heavy oil into gasoil, or wide range diesel fuel.
A more stable
operation and constant reaction temperature are obtained when the reactor is
operating under
pressure, instead of a vacuum. Also, conversion of the heavy oil into gasoil
is increased when a
sweep gas is injected into the reactor.
The following two examples illustrate how the heavy oil, produced from used
lubricating oil
treated with the process, surprisingly proved to be effective in cleaning
fouled equipment.
Example 5:
Used lubricating oil was being treated in a unit with a rotating kiln and heat
exchangers became
plugged. The exchangers were too hot to open or to treat with acetone. It was
decided to try
back washing the exchangers using the heavy oil, directly from the bottom of
the wash column,
because that oil, at 350 C, was hot and the pump could develop up to two
atmospheres in
pressure. The heat exchangers were unplugged and clean in a matter of minutes.
The fouling
material, along with the heavy oil, were routed back to the dehydration vessel
where they mixed
with fresh used oil feed and became reactor feed oil.
54
CA 02757061 2011-10-20 1
Example 6:
When the same heavy oil was first tested as a component in a floatation oil,
although the
floatation oil tanks had been cleaned prior to the test, the oil arrived at
the floatation cells very
dark and containing gums and solids. Although the lines had been flushed
before the test, the
new oil had cleaned the remaining deposits out of the floatation oil feed
system. The new oil
proved to be more effective than hot water and steam as a defouling agent.
Advantages of the Process
This waste oil thermal cracking process has many advantages over other waste
oil cracking or
reuse processes:
1. It is simple and easy to operate.
2. It is flexible and can treat a wide variety of waste oils, not just used
lubricating oils from
service stations and the like.
3. About 99% of the metals and 75% of the sulphur, present in waste oil, exit
the process with
the non-leachable coke before the vapours exiting the reactor are condensed.
The sulphur
and metals do not enter into the finished oil products.
4. All the products from this process are safe and can be sold in current
markets. There is no
product or by-product to dispose of in incinerators or industrial waste dumps.
5. The heavy oil produced can be used to back-flush and clean heat exchangers
and other equipment on site. There is no need to pre-treat the waste oil
feedstock to prevent equipment
fouling. Therefore, the laboratory analyses and chemicals required by the
waste oil feed pre-
treating unit are not needed, neither is their spent chemicals disposal.
6. The oil used to clean equipment on site and containing fouling material can
be processed in
the mobile plant and reused.
This waste oil thermal cracking process has many advantages over waste oil
recycling processes:
1. It is simple and easy to operate.
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CA 02757061 2011-10-20
2. It is flexible and can treat a wide variety of waste oils, not just used
lubricating oils from
service stations and the like.
3. The products do not need to meet the stringent specifications of
lubricating oil basestocks.
This eliminates the need for careful selection of feedstocks, leaving most
waste oils to be
disposed of into the environment.
4. The additives in the waste oil feedstocks are destroyed and about 99% of
the metals and 75%
of the sulphur, present in waste oil, exit the process with the non-leachable
coke before the
vapours exiting the reactor are condensed. There is no need to dispose of the
heavy oil
fraction, containing most of the metals and sulphur.
5. All the products from this process are safe and can be sold in current
markets. There is no
product or by-product to dispose of in incinerators or industrial waste dumps.
6. The heavy oil produced can be used to back-flush and clean heat exchangers
and other
equipment on site. There is no need to pre-treat the waste oil feedstock to
prevent equipment
fouling. Therefore, the laboratory analyses and chemicals required by the
waste oil feed pre-
treating unit are not needed, and neither is their spent chemicals disposal.
The resulting
soiled back-flushing oil can be recycled to the dehydration unit, and/or to
the reactor, and
reused. There is no need to treat waste water and/or to dispose of oily wastes
in industrial
dumps or landfills.
7. It is viable in smaller plants, with a smaller collection radius and does
not need to be
subsidized by governments.
Presently water is used to clean ships bunker reservoir, tank farm bottoms and
other equipment
that is fouled by heavy oils and/or other hydro-carbon residue. This means
that the water used
has to be separated from the oily residues and then the residues treated or
burned in cement
kilns. The burning of the oily residues is bad for the environment and a waste
of the hydrocarbon
resources.
The present invention can take the residues and produce diesels, additives for
asphalt and heavy
oils that can be used to clean the residues. By using these oils to clean the
tank bottoms and other
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CA 02757061 2011-10-20
reservoir the cleaning process is more efficient and there is no need to
separate water from the
residue. All the residue and the oil can then be pumped out and treated.
By having a mobile plant it would be possible to produce the heavy polarized
oils to clean the
tanks and equipment and then treat the residue and heavy oils to obtain
commercial products
and more oil to continue the cleaning process. Thus the mobile plant permits
more effective
periodic cleaning of tank farms and refinery equipment and other places with
reduced transport
of waste oils which are hazardeous material.
Also a mobile plant can also be used to treat waste oils in regions with low
density of population,
near out of the way mines or industrial complexes and where the volumes of
oils to be treated at
any given time is low and the cost of transporting the oils is high or could
lead to ecological
disasters during the transport. Presently, most of the waste oils in these
regions are burned or
thrown away which is very bad for the environment. A mobile plant would be
transported on a
periodic basis in these regions to treat the oils and sell the product in the
region.
The mobile plant could be built within a standard 45 feet hicube container and
thus could be
easily transported by truck, rail or boat.
In summary some of the advantages of the new thermal processing apparatus
include:
= A steady and controllable reaction temperature,
= A specified product slate of consistent quality,
= Protection of the reactor wall from stress and failure due to thermal shock
or hot spots,
= Preventing coke from depositing and sticking on the reactor walls and
internals,
= Longer run times, shorter shut-downs, less maintenance cost,
= Safer operation,
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CA 02757061 2011-10-20
= A steady and controllable reaction pressure, and
= Minimizing of the thermal stress on the reactor walls and/or on the
internals.
Some embodiments of the invention may have only one of these advantages, some
embodiments
may several advantages and may have all of simultaneously.
ADVANTAGES OF THE PROCESS OF THE INVENTION
This is a simple process that can treat a wide variety of waste oils and make
useful and
environmentally friendly products.
This process is in energy equilibrium. When used lubricating oils are
processed, the produced
gas and naphtha are consumed on site, and there is little or no need to
purchase fuel, or to use the
more valuable wide range diesel or heavy oil products from the plant. There is
also no naphtha
to dispose of.
When produced, the wide range diesel is a light amber colour. The produced
diesel is unstable
and will darken with time or when exposed to air. The diesel deteriorates much
faster, within
days instead of months, if there is no inert gas injection into the reactor
inlet. Injection of inert gas
results in a higher yield of diesel oil (from 78% vol. to 82% vol. of the
total liquid product) and
lower yield of naphtha (from 10% vol. to 6% vol. of the total liquid product).
Depending on the sulphur content in the feed oil, the sulphur in the diesel
produced could be
below the 0.1% weight., now specified in Europe for home heating oil.
The heavy oil is a low sulphur fuel. It can be sold as bunker fuel, or as a
specialty oil. It is also
used as backwash oil in the process plant. Plants that process waste oils face
constant fouling of
their equipment. Used lubricating oil re-refining facilities usually pre-treat
their feedstock with
chemicals to remove as much of the metals and solids as possible. They have to
test each truck
load entering the plant and must add the purchase of chemicals and the
disposal of spent
chemicals to their operating costs. Thermal cracking units that treat used
lube oils, are usually
much smaller than re-refiners. They have frequent shutdowns to remove coke
deposits and clean
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CA 02757061 2011-10-20
heat exchangers. In this process, heat exchangers can be cleaned while the
plant is on stream
using the backwash oil on site. The solids exit the plant with the coke.
The sulphur and metals, released in the cracking reactions, are attached to
the coke. The coke is
removed from the vapour oil stream as it leaves the reactor. Therefore the
sulphur and metals are
not present when the oil is condensed into liquid fuels. This is why the oil
products leaving the
plant are low in sulphur and metals, when compared to products from other used
oil thermal
cracking facilities. The metals in the coke are thought to act as catalysts in
the deterioration of the
oil products. The diesel oil produced with this process are more stables than
oils produced in
other thermal cracking units. The coke is non-leachable and can be disposed of
in landfills. It can
also be blended in asphals or cements.
This is a dry process: there is no liquid level in the reactor. The reactor
temperature is not limited
to the boiling point of the oil feed. This process can treat a much wider
variety of waste oils than
the conventional thermal cracking units. As an example: synthetic oils are
increasingly used as
base oils. They are more stable than conventional base oils and do not need to
be changed as
often to keep engines in good running order. Less oil changes mean less
feedstock to used lube
oil plants and the feedstock they get contains more contaminants. In a
conventional plant, since
the reactor temperature is limited to the boiling point of the oil, he more
stable oil will require a
longer residence time to crack, which limits the plant throughput and
profitability.
The process is very flexible. Since the reactor temperature can be changed to
suit, this process can
be used to treat waste oils that are not necessarily used lubricating oils
such as refinery tank
bottoms. It can also treat oils that have a high propensity to form coke such
as bitumen or
marpol.
The reactor in the process is under pressure which results in a more stable
operation, and
consistent product quality and quantity. A rotating kiln under positive
pressure is safer because
there will be no oxygen ingress into the reactor, which, if left undetected,
could result in an
explosion. In the event of a leak, oily vapours would exit into the firebox
and would burn in an
environment designed to contain flames.
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One of the safety features of this process is that there is no vessel
containing large amounts of oil
in this process. Residence times are low. The only vessel that might contain
large amounts of oil
is the dewatering flash drum. It is under a steam atmosphere. In an emergency
the equipment
can be drained within minutes, and steam or another inert gas, is already
present in the reaction
and product separation units.
The present invention can take the residues and produce diesels, additives for
asphalt and heavy
oils that can be used to clean the residues. By using these oils to clean the
tank bottoms and other
reservoir the cleaning process is more efficient and there is no need to
separate water from the
residue. All the residue and the oil can then be pumped out and treated.
By having a mobile plant it would be possible to produce the heavy polarized
oils to clean the
tanks and equipment and then treat the residue and heavy oils to obtain
commercial products
and more oil to continue the cleaning process. Thus the mobile plant permits
more effective
periodic cleaning of tank farms and refinery equipment and other places with
reduced transport
of waste oils which are hazardeous material.
Also a mobile plant can also be used to treat waste oils in regions with low
density of population,
near out of the way mines or industrial complex and where the volumes of oils
to be treated at
any given time is low and the cost of transporting the oils is high or could
lead to ecological
disasters during the transport. Presently, most of the waste oils in these
regions are burned or
thrown away which is very bad for the environment. A mobile plant would be
transported on a
periodic basis in these regions to treat the oils and sell the product in the
region.
The mobile plant could be built within a standard 45 feet hicube container and
thus could be
easily transported by truck, rail or boat.
Also cleaning with oil is better for corrosion purposes and leaves no water
residues in the
equipment, which could become safety hazards when the equipment is put back
into service.
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Among the products are cracked heavy oils that can be used to dissolve and
clean the fouling
agents deposited in equipment. The cleaning oil, along with the foulants
removed from the
equipment can be treated in the mobile plant, making useful products.
Although the present invention has been described with the aid of specific
embodiments, it
should be understood that several variations and modifications may be grafted
onto said
embodiments and that the present invention encompasses such modifications,
usages or
adaptations of the present invention that will become known or conventional
within the field of
activity to which the present invention pertains, and which may be applied to
the essential
elements mentioned above.
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