Note: Descriptions are shown in the official language in which they were submitted.
CA 02750129 2011-08-17
THERMAL PROCESS TO TRANSFORM CONTAMINATED OR UNCONTAMINATED FEED
MATERIALS INTO USEFUL PRODUCTS, USES OF THE PROCESS, PRODUCTS THEREBY
OBTAINED AND USES THEREOF, MANUFACTURING OF THE CORRESPONDING PLANT
FIELD OF THE INVENTION
The invention relates to a process to thermally treat contaminated or
uncontaminated feed materials such as
contaminated or uncontaminated feed oils, more particularly such as used
lubricating oils, waste oils, oily tank
bottoms, heavy oils, Marpol or bitumen, in a rotating kiln operating under
pressure and/or with the injection of a
gas, preferably with injection of a sweep gas into the reactor or into its
feed stream.
BACKGROUND OF THE INVENTION
Waste oils, especially used lubricating oils (ULO), are considered a threat to
the environment, and is 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." 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.
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.
There is a need for a viable, safe and flexible process that can destroy the
hazardous components in used oil while
making products and by-products that are all environmentally friendly.
The re-refining processes alluded to in the previous section aim to recover
lubricating oils from the used oil feed
streams. There are processes that want to destroy the metal-containing
additives in waste oils, and make
environmentally acceptable products such as fuels:
Many of these patents propose stationary reactors, operating at atmospheric
pressure:
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.
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
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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
625 OF to 725 OF 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
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
substantially contaminant-free product oil. The contaminant-rich solids are
collected for disposal. This process
operates at a negative pressure in the reactor.
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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.
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 850 OF to about 1000 OF 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.
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,
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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.
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.
There is a need for a flexible and viable process that addresses the drawbacks
of existing technologies and that
can destroy the harmful components in waste oils while making products and by-
products that are useful and
environmentally friendly.
SUMMARY
A process for thermally treating an oily feed in a reactor comprising a
rotating kiln operating under a positive
pressure 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
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 feed stream entering the said rotating
operating kiln; or a process for thermally treating an oily feed in a reactor
comprising a rotating kiln operating
under a positive pressure 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
a rotating kiln operating 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, 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. Heavy oil, as obtained by a process thereby obtained. The use of a heavy
oils thereby obtained in
environmental or non environmental applications.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 0: is a simplified flow diagram illustrating a version of the process
according to the present invention.
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.
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.
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Figure 9: is vertical cross section of reactor according to an embodiment of
the invention in a slanted position.
Figure I OA: is a front view of a screen made of wire mesh.
Figure I OB: 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.
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.
GENERAL DEFINITION OF THE INVENTION
Preliminary definitions
For the purpose of this document, the following definitions are adopted:
Feed material: contaminated or uncontaminated feed materials such as
contaminated or uncontaminated feed oils,
more particularly such as used lubricating oils, waste oils, oily tank
bottoms, heavy oils, marpol, waxes and
bitumen. Solid feedstocks could include oil sands, oil shales, and wastes such
as rubber, plastics, asphalts and
other hydrocarbons.
Sweep gas: is any non reactive or substantially non reactive gas, preferably
it is an inert gas such nitrogen,
recycled reactor non-condensable gas or water steam. It was surprisingly found
that such gas not only have as
sweeping effect in the reaction zone of rotating operating reactor, but may
create a suppression, may increase the
safety in plant operations, may help control the reactions in said reactor and
globally may improve the efficiency
of the process. For example, the sweep gas is a gas stream that may
additionally serve in various the following
functions such as:
= when injected into the reactor feed line, the sweep gas changes the density
of the total feed stream; it
changes the flow regimes within the feed line and/or nozzles, which results in
lower incidence of fouling
and plugging of the piping and spray nozzles, and in improved spray patterns;
further, the sweep gas
favours atomization of the oil stream before the oil reaches the reaction
sites on the hot plates, and/or
= if introduced into the liquid feed at temperatures above that of the
hydrocarbon liquid stream, it will
increase the feed stream temperature and reduce the energy, or heat, provided
by the kiln, and/or
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= It reduces the oil's residence time in the reactor, by sweeping the
hydrocarbon vapours out of the reactor
soon after they are formed, thereby reducing the incidence of secondary
reactions, or over-cracking,
resulting in higher liquid yields and more stable liquid product oils, and/or
= the sweep gas present in the reactor reduces the liquid oil's partial
pressure, and favours the vaporization
of the lighter oil fractions, such as the gasoil and naphtha, in the feed and
products; this also reduces over
cracking in the gasoil fraction and increases the stability of the hydrocarbon
liquid products, and/or
= the sweep gas helps to stabilize the pressure in the reactor, and/or
= when steam or nitrogen are used, the sweep gas reduces the risk of fires in
the event of a leak in the
reactor or in the downstream equipment; it will disperse the oil escaping and,
hopefully, keep the oil from
igniting, even if it is above its auto-ignition point, and/or
= it can also be part of the stripping gas stream in the product distillation
unit.
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 500 C, according to ASTM D-86.
Naphtha: 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 (ULO): 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: is a gas such as nitrogen, recycled reaction
gas or water steam that does not affect
or enter into the thermal processing or that does not substantially affect the
thermal processing in a temperature
range up to 700, preferably up to 400 degrees Celsius.
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.
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 any change in phase and/or composition,
and/or reactions initiated or facilitated
by the application, or withdrawal, of heat and/or temperature. Examples of
thermal processing include
evaporating, cracking, condensing, solidifying, drying, pyrolizing and
thermocleaning.
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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.
In this process, the feed oil, which may have been chemically pre-treated, is
heated and its water removed
preferably in a flash evaporator. The dewatered oil may be heated again to a
temperature close to, but below, its
initial thermal cracking temperature. This heating step is accomplished either
by heat exchange with a hot oil
stream, by the injection of a hot gas, by direct contact with a hotter oil
stream, or by a combination of these
methods. The resulting reactor feed stream is sprayed unto metal plates in a
rotating kiln, where it is thermally
cracked and/or vaporized. The reactor operates under positive pressure. The
reaction products, hydrocarbon
vapours and solid coke, are swept out of the reactor as soon as possible to
prevent secondary reactions. Most of
the coke is removed from the hydrocarbon stream, before the oil is condensed,
usually in cyclones. The residual
coke is washed out for the hydrocarbon vapours preferably in a wash column or
in a dephegmator. The
hydrocarbon product stream is condensed and separated into specified products.
The non-condensable gas, heated
or non heated gas and possibly the naphtha is(are) used as fuel on site.
More specifically, the first objet of the present invention is:
- a) a process for thermally treating an oily feed in a reactor comprising a
rotating kiln operating under
positive pressure 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
recovered separately or in the form of mixtures of at least two of these
latter 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 feed stream entering the said rotating operating kiln;
or
- b) a process for thermally treating an oily feed in a reactor comprising a
rotating kiln operating under a
positive pressure 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
latter components; or
-c) a process for thermally treating an oily feed in a reactor comprising a
rotating kiln operating 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 latter 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.
Advantageously, the oily feed is selected among contaminated or uncontaminated
oils such as 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.
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According to a preferred embodiment, the vapours and the solids exiting the
kiln are routed to vapour solid
separation means.
Advantageously, the vapour solid decantation means are a stationary box and/or
a heated cyclone for the heavier
solid and/or then are sent to an a cyclone(s) to separate most of the solids
present in said vapours exiting the
rotating kiln from the said vapours.
According to a preferred embodiment, the solids present in said vapours
exiting the rotating kiln are selected
among: 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.
The vapour-solid separation equipment, preferably the separation box and/or
the cyclones, is (are) preferably
heated, at a temperature that is(are) above the temperature of the vapours
existing the kiln, more 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.
Advantageously, the vapour solid separation equipment, preferably the cyclones
and/or the separation box, are
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 is advantageously a dry coke, i.e. this
coke preferably contains less than 2
weight percent of oil.
According to a preferred embodiment, 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.
Advantageously, the vapours exiting the vapour solid separating equipment,
such as cyclone(s), are partially
condensed in a self refluxing condenser and/or in a wash tower, to complete
the solids removal from the reactor
products.
According to a preferred embodiment, the vapours exiting the last set wherein
solids are eliminated, preferably
this step takes 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.
Advantageously, said heavy oil, containing the residual, are recycled in the,
preferably in a dewatering step when
present, and/or in the oil feed entering at the beginning of the process,
and/or in the reactor feed oil entering the
rotating kiln.
CA 02750129 2011-08-17
According to a preferred embodiment, wherein said recovered heavy oil and the
fractionator bottom oil can also
be used as back flushing oils to clean fouled equipment.
Advantageously, in the rotating kiln, ranges from I to 4 atmospheres,
preferably this pressure ranges from 1.2 to
1.5 atmospheres and/or the feed oil is, before entering said rotating
operating reactor, heated, preferably at a
temperature that is at least 20 degrees Celsius under the cracking temperature
of the feed oil.
According to a preferred embodiment, the water is removed from the feed oil
before the feed oil enters the
reactor, preferably in a flash evaporator, from the feed oil, before the said
feed oil enter the rotating kiln.
The feed oil entering the rotating kiln may also be an oil that, due to its
history and/or due to its origin, was
previously chemically treated, or slightly chemically treated due to its
history or to reduce its metal content, thus
the feed oil may have been treated by at least one acid and by at least one
base, the acid being advantageously a
sulphur acid and/or a phosphoric acid.
According to an alternative mode, the feed oil is physically and chemically
pre-treated before entering the said the
process.
Advantageously, the heating step(s) 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.
Alternatively, 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, advantageously comprises
hydrocarbon vapours and other vapour
present in the reaction zone of the rotating operating kiln and solid coke.
Advantageously, the reaction products exiting the rotating operating kiln are
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.
Reactor residence time is a function of the feed oil composition, of the
pressure in the reactor, of the temperature,
and/or of the desired products slates.
According to an alternative embodiment of the process, the reaction products,
when swept out of the said rotating,
are heated at a temperature that is advantageously slightly over the
temperature at the exit of the reactor.
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CA 02750129 2011-08-17
Advantageously, 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
and/or in a self reflecting condenser.
According to a preferred embodiment, the hydrocarbon product stream is
condensed and separated into specified
products and/or at least part, and preferably all, the non-condensable gas
produced in the said rotating operating
kiln is used as fuel on site and/or at least part, and preferably all, the
naphtha present in the feed oil and/or
produced in the said rotating kiln is used as fuel on site.
Advantageously, the sweep gas is super heated steam and/or the sweep gas
represents in weight up to 30 % of the
weight of the feed oil, more preferably up to 10 %, and more preferably
between 0.5 and 5 % of the weight of the
feed oil.
According to an alternative embodiment, the cyclones are outside of said
rotating operating reactor but inside a
second enclosure, said second heated enclosure communicating or not with the
first reaction's zone in order to
benefit of a hot flue gas flow surrounding said cyclones.
According to a preferred embodiment, at least part of the purified oils
definition recovered is used on the site to
clean the heat exchanger(s).
Advantageously, wherein the residence time in the rotating kiln ranges from 3
minutes to 15 hours, and this time
is preferably comprised between 2 minutes and 30 minutes. At least part of the
purified recovered oil may be used
on the site or sold to clean heat exchangers and/or any other fouled
equipment.
According to a preferred embodiment, the demetallisation of the total oil
liquid products (heavy oil, wide range
diesel and naphtha) recovered during said process is of at least 90 %,
preferably of at least 95 % and more
preferably of at least 99 %.
Advantageously, the total recovered oil contains less than 60 PPM of metal.
According to another preferred embodiment, the metals mainly present in the
recovered total oil products are
mainly copper, iron and zinc, the other metals being at a level that is
inferior to I PPM and/or 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 %.
Alternatively, the main components in the recovered gas are non condensable
gas such as methane, ethane,
ethylene, propane, propylene, nitrogen, carbon monoxide, carbon dioxide and
gas containing sulphur and halides.
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Advantageously, the gas and the naphtha produced are used as fuel on site to
satisfy the energy self sufficiency of
the plant in function.
According to another preferred embodiment, the recovered oil is characterized
in that is has no sulphurous content
or less than 3 000 ppm of the sulphur in the mixture. Sulphur content in the
liquid products depends on many
factors such as the sulphur content in the feed, on the reactor operating
conditions, on the efficiency of the solids
removal from the reactor product stream.
Alternatively, a limited amount of Marpol is injected in the feed oil that is
preferably of the type present at the
bottom of a ship fuel tank and the amount of Marpol represents from 10 to 95 %
of the weight of the feed oil.
Advantageously, a limited amount of an oily product containing up to 98, more
preferably up to 99, weight % of
sweet water and/or of salted water, is injected in said reactor, provided the
oil is at a temperature that is lower
than water's vaporization temperature at line pressure.
According to a preferred embodiment, the rotating kiln used in the process of
the invention contains a charge
made 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.
The processes of the present invention are particularly suited for the thermal
processing of a mixture, wherein
thermal processing being 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.
Advantageously, said plates when moving inside said reactor clean the walls of
said reactor and/or said plates
protect at least part of the walls of said reactor and avoid reactor wall
failure due to thermal shock.
According to a preferred embodiment, said plates contribute to the uniformity
of temperatures conditions in said
reactor and/or said plates contribute to the heat transfer taking place from
the heated walls to the surface of said
plates, particularly on the surfaces of those plates wherein thermal
processing occurs and/or said plates contribute
to avoid spraying of cold mixtures on the heated walls of said reactor, and
avoid reactor wall failure due to
thermal shock.
According to another preferred embodiment of the invention, said reactor
comprises:
a. a rotating kiln;
b. a heating system;
c. at least one shelf on the reactor wall;
d. a charge of plates of consistent shapes;
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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 fine 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.
Preferably, 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, and more preferably, the at least one shelf
is 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.
Advantageously, said means for bringing the mixture to be thermally processed
on the surface of at least part of
the plates, 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.
The mixture to be thermally processed is advantageously a liquid, gas and/or
solid and/or is a mixture of at least
two of these, preferably said mixture comprises mostly organic compounds that
may be transformed by thermal
processing, more preferably said mixture comprises at least 80 %, preferably
at least 90 %, more preferably at
least about 95 % of organic compounds that may be transformed by thermal
processing.
The process of the invention is advantageously used for treating mixtures that
are contaminated soils and/or
bitumen that preferably comprise up to 100 %, preferably at least 5 %, of
organic compounds that may be
transformed by thermal processing; advantageously in the case of oils sands
and shale oils, the mixtures have only
5 % to 12 % oil, the remaining being sand/or earth or shale.
Advantageously, said process is used to treat mixtures that may comprise other
components that are not organic
compounds and/or that may not be transformed by thermal processing.
Said other components, alone or in a combination, may be selected among:
water, steam, nitrogen, sand, earths,
shale, metals, organic salts, inorganic salts, inorganic acids, organic acids,
organic basis, inorganic basis, lime,
organic gas and inorganic gas that won't be transformed in the reactor and
among mixtures of at least two of these
components.
Advantageously, the treated mixtures are composed of organic compounds that
may be transformed by thermal
processing in: a liquid phase, a gaseous phase, a solid phase, or in a
combination of at least two of these phases
and/or said mixture are mostly composed of organic compounds that may be
transformed by thermal processing,
in at least a liquid phase, a gaseous phase and a solid phase.
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According to a preferred embodiment, the reactor feed oil is substantially
free of an organic liquid and of a slurry
phase.
The processes of the invention, may operate in less than 10 % vol., preferably
in less than 5% vol. of an organic
solid, and/or liquid and /or of a slurry phase and/or operate in the absence
of an organic solid, liquid and/or slurry
phase.
In the processes of the invention, the said rotating kiln rotates around its
centre axis, the said axis is horizontal or
slanted.
Advantageously, the rotating kiln rotates 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.
According to another preferred embodiment, 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 and/or the walls of said reactor are directly and/or
indirectly heated.
Advantageously, the inside of the reactor is directly and/or indirectly heated
and/or the heat source is 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.
The inside of the reactor may be 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.
According to a preferred embodiment, the heating means comprises at least one
heating system external to the
walls of the reactor which is usually the case of an indirectly fired kiln.
Alternatively, the external walls of the reactor may be partially surrounded
by, or exposed to, one or more burners
and/or exposed to combustion gas and/or hot solids.
The walls of said reactor are advantageously surrounded by a fire box, and
said fire box is stationary and may
contain one or more burners.
According to another preferred embodiment, one or more shelves are attached to
the internal walls or the external
walls of said reactors and/or the shelve (s) is (are) are 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).
CA 02750129 2011-08-17
Advantageously, the shelve(s) is(are) held by T shaped clamps and/or the
shelve(s) is(are) symmetrically attached
to the internal wall of said reactor and/or the shelve(s) is(are) attached to
the internal wall in a designed and/or
random pattern of said reactor .
According to another preferred embodiment, 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
from 1 to 40, preferably from 2 to 20
and/or 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 from I to 50 units, more preferably from
2 to 20, advantageously from 3 to 15
and this number is more advantageously about 4.
The number of shelves in the reactor may depend on the weight 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.
Advantageously, the space between two shelves represents from 0 to 100 %,
preferably this space from 5% to
100% of the radius of the cylinder.
Alternatively, 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.
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.
Advantageously, 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 processes of the invention wherein the form of the shelves in the rotating
reactor is selected in the group
constituted by flat, concave, convex, spiral and slanted are of a particular
interest.
Advantageously, 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 30 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, more
preferably, the height or width of the shelves
ranges from I to 8 cm.
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According to a specific embodiment, 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 and/or the width and the
height of the shelves are selected in
order for the shelves to be able to retain 2 to 3 plates.
The height of the shelves is, advantageously, at least about the thickness of
the plates, preferably about twice the
thickness of the plates and/or the shape of the plates of the charge is
selected among the group of parallelograms,
such as square, rectangles, lozenges, or trapezes.
According to a preferred embodiment, the plates of the charge are rectangular,
triangular, hexagonal or octagonal
and/or the shape of the plates of the charge is perfect or imperfect, or about
perfect.
Advantageously, all the plates present in the reactor have about the same size
and shape.
According to another preferred embodiment of the invention, the volume of the
plates of the charge present in the
reactor represents from 1 % to 25% of the internal volume of the said reactor
and/or the volume of the plates of the
charge present in the reactor represents about 4%, of the internal volume of
the said reactor.
Advantageously, the charge of the reactor is constituted by flat and/or
slightly curved metal plates of consistent
thickness and shape and/or by plates having a melting point which is at least
of 100 degrees Celsius, and more
preferably is of at least 150 degrees Celsius above the reactor wall maximum
operating temperature in the thermal
processing zone.
According to a preferred embodiment, the rotating reactor used is
characterized by plates are heavy enough to
scrape coke or other solids off the reactor wall and/or off other plates, more
preferably each plate has a density
that is superior to 2.0-g/cm3, preferably superior to 2.0-g/cm3 and more
preferably comprised between 5.5 g/cm3
and 9.0 g/cm3.
Advantageously, the means for bringing the mixture in contact with at least
part of the surfaces of the plates are
spraying means and/or a conveyor, more advantageously, the 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 is mixture of liquid and/or gas.
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 advantageously
comprise an exit hopper arrangement
attached to the solids exit tube.
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According to another preferred embodiment, said reactor has two exits: one for
the solids and one for the
gas/vapours and entrained solids obtained,
Advantageously, the gas/vapours obtained during the thermal processing contain
entrained solids.
Additionally, said reactor is equipped with means for avoiding accumulation of
solid in the reactor and/or for
plugging of any of the exits.
Advantageously, the means for avoiding accumulation are a screw conveyor in
the solids exit tube, or a slanted
solids exit tube and/or the reactor is a cylinder, or a cylinder with two
conic extremities, or two cones attached by
their basis, or a sphere.
In a preferred embodiment, the reactor is a heated cylinder having a length to
radius ratio ranging from I to 20
and preferably ranging from 2 to 15, more preferably this ratio is about 10.
According to another preferred embodiment of the invention, the processes of
the invention are performed with 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 thus preferably
comprise a tube and/or at least a ring
surrounding said feeding line, said surrounding tube and/or surrounding
ring(s) being attached to the internal wall
of the reactor and leaving at least part of the feeding line not surrounded.
The diameter and/or the constituting material of the surrounding tube and/or
of the surrounding ring(s) is (are)
advantageously selected in order to allow the thermal expansion of said
feeding line support ring.
According to an embodiment of a particular interest, 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.
Advantageously, the length of the attachment means of the second tube and/or
of the at least a second ring is
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; more preferably, the length of the
attachment means of the second tube and/or of
the at least a second ring is 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 a second ring to the internal
wall of the said reactor.
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Advantageously, 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 preferred 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.
Advantageously, some, preferably each, of the said attachment means are
articulated to their attachment point.
According to another preferred embodiment, the reactor feed is made laterally
trough one end of said reactor, and
the exits of the vapours obtained during the thermal processing is positioned
on the same end or at the opposite
end of said reactor.
Advantageously, the reactor feed is made laterally trough one end of said
reactor, and the exit of the cokes
obtained during the thermal processing is positioned on the same end or at the
opposite end of said reactor.
The reactor feed is advantageously made laterally trough one end of said
reactor, and the exits of the vapours
obtained during the thermal processing is advantageously positioned on the
same end or at the opposite end of
said reactor.
According to a preferred embodiment, the rotating kiln used to perform the
process of the invention has heating
means inside allowing the thermal processing to occur on the plates that are
heated on the external walls of the
kiln. In this configuration, the shelves are advantageously attached to the
exterior surface of the kiln and/or the
external walls of the kiln face the internal wall of the said stationary
housing.
The feeding of the mixture is advantageously performed on the top of the
reactor and preferably is at equal
distance of each end of the reactor
The exit of the vapour is advantageously positioned on a side of the walls of
the reactor and preferably at equal
distance of both ends of said reactor.
According to another preferred embodiment, the exit of the coke is positioned
on a side of the walls of the reactor
and preferably at equal distance of both ends of said reactor.
Advantageously, the exit of the solids is on the bottom of the reactor and
preferably is at equal distance of each
end of the reactor.
Those processes of the invention wherein the continuous or semi-continuous
thermal treating of the feed oil is
performed are of a particular interest.
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CA 02750129 2011-08-17
The processes of the invention are of a particular interest when applied to
the treatment of feed oils which
comprises organic compounds having the following thermodynamic and physical
features: a specific gravity as
per ASTM D-4052 between 0.75 and 1.1, and/or distillation temperatures, as per
ASTM D- 1160, ranging from
-20 C to 4 000 C, more preferably ranging from 20 C to 950 C.
The average residence time in the rotating kiln ranges advantageously from 5
seconds to 10 hours, preferably
between 30 seconds and 2 hours, and more preferably is between 90 seconds and
10 minutes.
According to another preferred embodiment, the average oil and feed oil
residence time in the rotating kiln is,
when:
- a positive pressure is present in the rotating kiln, comprised between 0.5
seconds to 2 hours; or
- a sweep gas such as nitrogen is injected, in the feed stream or in the
rotating rector, comprised between
I and 10 minutes for used lubricated oil and comprised between 2 and 15
minutes for heavy oils.
According to another preferred embodiment, the average residence time in the
rotating kiln is, when:
- nitrogen as sweep gas is injected in the feed stream in an amount up to 15
weight %, preferably in an
amount up to 10 weight %, comprised between 5 seconds and 15 minutes,
preferably between 8 and 10
minutes; and
- water steam is is injected in the feed stream in an amount up to 10 weight
%, preferably in an amount up
to 5 weight %, comprised between 0.5 minutes and 15 minutes, preferably
between 4 and 5 minutes.
The heating temperature in the rotating kiln may range advantageously from 350
C to 750 C.
Preferably the heating temperature on the surface of the plates in the reactor
ranges from 390 C to 500 C, more
preferably from 420 C to 455 C and, more advantageously, is :
- about 425 C particularly when used lube oils are treated;
- between 250 C an 500 C, preferably between 300 C and 400 C, when vegetal
oils or animal fats are
treated .
According to another preferred embodiment, the heating temperature in the
reactor ranges from 500 C to 520 C,
an is preferably about 505 C, more preferably about 510 C particularly when
shredded tires, bitumen, heavy oils,
contaminated soils or oil sands or soil contaminated with heavy oils are
treated.
The rotation speed of the rotating reactor advantageously ranges from 0.5 rpm
to 10 rpm.
The rotation speed of the rotating reactor depending on the size of the
reactor and on the process requirements,
may advantageously range from ranges from I rpm to 10 rpm, preferably 2 to 5
rpm from and is more
advantageously about 3 rpm, for example in the case of a reactor treating 400
barrels of used oil per day.
CA 02750129 2011-08-17
According to a preferred embodiment of the process of the invention, the
various fractions generated by the
thermal processing are recovered as follow:
- the liquid fraction is recovered by distillation
- the gaseous fraction is recovered by distillation; and
- the solid fraction is recovered for example in cyclones, a solids recovery
box, a scrubber, a wash tower
and/or a self refluxing condenser.
Preferably are those processes wherein
- the amount of the recovered liquid fraction represents between 85% and 100%
weight of the organic reactor
feed; and/or
- the amount of the recovered gaseous fraction represents between 0% weight
and 10% weight of the reactor
feed; and/or
- the amount of the recovered solid fraction represents between 0% weight and
5% weight,
when the feedstock is used lubricating oil
Said processes are advantageously operated in a continuous or in a batch mode.
A second object of the present invention is constituted by non environmental
and by environmental uses of the
processes defined in the first object of the present invention.
Among those uses, those:
- 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
- recovering energy and/or fuels from used tires and/or plastics;
- recovering energy and/or fuels from wood chips and/or paper;
- use in coal-oil co-processing; and/or
- recovering oil from oil spills; and/or
- PCB free transformed oils,
are of a particular interest.
Those for treating used oils and to prepare:
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- 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,
are also of a particular interest.
A third object of the present invention is a process for fabricating a plant
comprising a rotating reactor and its
internals for thermal processing according to the first object of the present
invention, which process comprises
assembly by known means the constituting elements of said reactor.
Advantageously, the known assembling
means comprise screwing, jointing, riveting and welding.
A fourth object of the present invention is the heavy oil, as obtained by a
process defined in the first object of
the present invention.
Heavy oils thereby obtained are polarized hydrocarbons and/or non-polarized
hydrocarbons or mixtures of latter,
and in those mixtures mainly made of hydrocarbons wherein at least part of the
mixture of hydrocarbons includes
polarized hydrocarbons, are of a particular interest.
Heavy oils thereby obtained and wherein the polarized hydrocarbons are
selected in the family constituted by the
polarized hydrocarbons having, according to ASTM method number D 1160, a
boiling point range between
160 C and 800 degrees Celsius, more preferably between 300 and 500 degrees
Celsius, are also of a particular
interest.
Among those heavy oils, those having a density, according to ASTM method
number D4052, at 20 degrees
Celsius, that ranges from 0.9 and 1.2 grams per millilitre, are advantageous
and those containing less than 10
weight % of solids are more preferred.
Another family of heavy oil thereby obtained are those wherein the solids are
selected in the family constituted
by:
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CA 02750129 2011-08-17
i. carbon residues, corresponding to a carbon coke ASTM D189 that is
preferably lower than 5 %,
more preferably lower than 3 %;
ii. sulphurous compounds wherein the sulphur content of said heavy oil is,
according to ASTM
D529 1, lower or equal to 5 %, above usually in the order of 1.5 % wt.
A fifth object of the present invention is constituted by the use of the heavy
oils obtained by a process defined
in the first object of the present invention or by the use of a heavy oil
defined in the third object of the present
invention:
- a fuel oil;
- a component of floatation oils or cleaning oils for equipment;
- a diluent for asphalt;
- a secondary refinery feed (preferably in a hydrocracking unit) to produce
diesel and other fuels;
- a transformer oil without PCB;
- a water repellent additive in asphalt and/or cement;
- a cleaner to remove dirt containing polarized particles such as, asphalts
and/or resins and/or metal
particles attached to equipment walls, in such a use said used oil is
preferably heated at temperature
ranging preferably from 0 to 400 C, and more preferably below its ignition
points (advantageously
C under its ignition point), and has a total hash metal content that is
advantageously below 3%
weight, preferably below 1 000 ppm wt., more preferably bellow 600 ppm wt.
more preferably bellow
20 60 ppm wt.;
- as substitute to creosol, particularly in the preventive treatment of
supporting railways wood beam;
and
- in the same application than the original use of the oil before its
contamination.
DETAILED DESCRIPTION OF THE PROCESS
Figure 0 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 (100) is filtered (102) and heated to approximately 90 C (103).
If necessary, the waste oil feedstock
may be filtered again or put through a decanter to remove as much solids (112)
as possible before entering the
dewatering unit. The feed oil is sprayed into a pre-flash drum (104) where a
pool of oil is kept hot by means of a
re-boiler heater (105). 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 (106) and the
water (107), naphtha (108), and
possibly the gas (109) are separated and pumped to the tank farm and/or are
used as fuel on site. The de-watering
23
CA 02750129 2011-08-17
system can operate at pressures up to 100 kPa gauge, preferably at pressures
up to 90 kPa gauge, and with hot oil
temperatures up to 360 C.
The hot and dry oil from the flash drum is heated (110), either through heat
exchange, by direct contact with a
hotter stream and/or put into a vacuum column. It is then routed to the
reactor. A gas stream (111), representing
between 0.1% wt. and 15% wt. of the reactor feed stream, is introduced into
the dry waste oil feed stream to the
reactor. When used lubricating oils are processed, and the gas used is steam,
the steam injection rate should be
around 4% wt. on dry feed.
The sweep gas stream is any non-reactive, or a substantially non-reactive, gas
that is introduced with the reactor
feed stream, or via another injection nozzle, into the reactor via a separate
nozzle. Examples of sweep gas streams
include water steam, nitrogen and reaction non-condensable gas at normal
conditions of atmospheric pressure and
C. By performing the process according to the present invention it has been
surprisingly found that the sweep
gas stream may additionally also serve a variety of functions such as, but
limited to, the following functions:
15 = when injected into the reactor feed line, the sweep gas changes the
density of the total feed stream; it
changes the flow regimes within the feed line and/or nozzles, which results in
lower incidence of fouling
and plugging of the piping and spray nozzles, and in improved spray patterns;
further, the sweep gas
favours atomization of the oil stream before the oil reaches the reaction
sites on the hot plates, and/or
= if introduced into the liquid feed at temperatures above that of the
hydrocarbon liquid stream, it will
increase the feed stream temperature and reduce the energy, or heat, provided
by the kiln, and/or
= It reduces the oil's residence time in the reactor, by sweeping the
hydrocarbon vapours out of the reactor
soon after they are formed, thereby reducing the incidence of secondary
reactions, or over-cracking,
resulting in higher liquid yields and more stable liquid product oils, and/or
= the sweep gas present in the reactor reduces the liquid oil's partial
pressure, and favours the vaporization
of the lighter oil fractions, such as the gasoil and naphtha, in the feed and
products; this also reduces over
cracking in the gasoil fraction and increases the stability of the hydrocarbon
liquid products, and/or
= the sweep gas helps to stabilize the pressure in the reactor, and/or
= the sweep gas helps to keep the velocity of the vapours exiting the reactor
stable, improving the solids-
vapour separation efficiency in downstream equipment;
= when steam or nitrogen are used, the sweep gas reduces the risk of fires in
the event of a leak in the
reactor or in the downstream equipment; it will disperse the oil escaping and,
hopefully, keep the oil from
igniting, even if it is above its auto-ignition point, and/or
= it can also be part of the stripping gas stream in the product distillation
unit.
The combined oil and gas stream is introduced into the reactor through one or
more spray nozzles (114) within
the rotating kiln (113) as described in the Canadian Patent Application
2,704,186. The kiln rotates within a
combustion chamber (115) which is fired by temperature controlled burners
(116). 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.
24
CA 02750129 2011-08-17
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 100 KPa(g). The kiln
operating temperature is determined by the
quality and quantity of the reactor feedstock, and by the quality and quantity
of the desired products, and by the
reactor volume or residence time available. It can vary between 380 C and 460
C 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 (117) separators
where the solid particles are removed from the hydrocarbon vapours. In a
preferred mode, the vapour-solids
separators are in a heated chamber (118) or heat traced to prevent dew point
condensation and plugging of the
equipment. The coke (131) and other solids drop by centrifugal force and
gravity, they are cooled (130) and sent
to storage. Normally, the coke and other solids exiting the reactor are non-
leachable.
The hydrocarbon vapours enter a flash drum (119) and self-refluxing condenser,
or scrubbing tower (120)
assembly, where the remaining coke is removed. The heavy oil from the bottom
of the flash drum (129) can be
mixed with the distillation column bottoms and/or recycled to the reactor feed
and/or used as back flushing oil
and/or sent to storage and sold. The vapours from the reactor are partially
cooled (132) and enter the product
separation unit (121). The vapours exiting the top of the main distillation
column are cooled (122) and are
separated in a three phase accumulator to yield the product gas (123), naphtha
(124) and water (125).
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, the rest is sent to storage. It
may be used as fuel in the plant. The gas is consumed on site as fuel in the
plant.
The diesel fraction (127) is pulled as a side cut, possibly through a
stripper, cooled (126) and sent to storage.
The column bottoms or heavy product (128) 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.
Preferred embodiments of the invention
The invention is that of the a process using an indirectly fired rotating kiln
(1), represented on Figures 1 and 2,
having preferably the following dimensions 8' by 20' containing a charge of
1100 metal plates (2) that are lifted
by one or more narrow shelves (3) as the reactor rotates at a speed comprised
between 0.5 and 10 rpm. 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
CA 02750129 2011-08-17
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.
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 failure due to the
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 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
26
CA 02750129 2011-08-17
when the feed to the kiln is interrupted and there is no vapour to carry the
coke out, or when there is a surplus of
coke, or the coke is wet with oil 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 I" 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, sliding 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.
27
CA 02750129 2011-08-17
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 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 5 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).
Figure 10 shows two possible configurations for the screens (36) in figures 7
and 9. Figure I OA 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
28
CA 02750129 2011-08-17
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 1 1 is a vertical cross section of a reactor in the slanted position,
about 5 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 (3 I), 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).
Figure 13 shows 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).
29
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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.
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).
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.
in
CA 02750129 2011-08-17
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
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 caused over pressuring of the reactor, failure of
the seals, escape of hot oil above its
auto-ignition temperature and fires. 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
The following examples are given as a matter of illustration and should not be
constructed as constituting any
limitation of the scope of the present invention in its generality.
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 I was performed with the injection of 5% wt. water added to the 16 1/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 feed.
In example 3, the oil feed rate was increased by 50% to 241/h, again without
water in the reactor feed.
Example 4 was performed on the same kiln but with a different oil sample.
Example 5 was performed on a larger
kiln with oil similar to that used in example 4.
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Example 1: with the injection of 5% wt. water added to the 16 Uh reactor feed
oil.
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.
.TABLE I - EXAMPLE I
Reactor Size: L = 1.07 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 D2276 mg/ml 0.5 0.05
Flash Point ASTM D92 C 128 48 <100
CCR D189 Weight % 3.34 1.01
Ash ASTM D4422 & ASTM 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. Water was also
injected into the reactor feed stream at the rate of 5% weight on dry oil
feed.
As shown on Table 6, a 72% 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.
Example 2: kept the same oil feed rate and similar operating conditions as in
example I but without water
injection into the reactor feed.
Please refer to the Table 2
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CA 02750129 2011-08-17
Table 2 - Example 2
Reactor Size: L =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 HeavyOil Coke
& Solids
Weight % on Dry Oil Feed 100 9.8 11.2 46.8 22.6 9.6
Density @ 15C ASTM D4052 g/ml 0.893 0.758 0.865 0.933 1.4
Molecular Weight g/mole 37.4
Water STMD1533 Volume % 0.7
Metals Digestion & ICP-IS ppm Weight 2160 3 Not Done 25510
Sulphur LECO 532 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 D2276 mg/ml 0.5 0.05
Flash Point ASTM D92 C 128 <0 48
CCR ASTM D189 Weight % 3.34 1.01
Ash ASTM D4422 & ASTM D482 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
- Example 2 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.
A dewatered waste oil stream of 16 L/h is injected in an indirectly fired
rotating kiln, containing metal shavings at
490 C to 500 C. 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 or water injection into
the reactor for this test.
As shown on Table 6, 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 reactor is cracked,
producing naphtha and gas. The
operation of the reactor during example I 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.
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Example 3: the oil feed rate was increased by 50% to 24 I/h, again without
water in the reactor feed.
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: 24 L/h
Test
I Method Units Feed Oil Gas Naphtha Gasoil HeavyOil 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 c5t 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 D189 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 I 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.
A dewatered waste oil stream of 24 L/h is injected in an indirectly fired
rotating kiln, containing metal shavings at
490 C to 500 C. The seals on the kiln were changed to permit pressures above
atmospheric in the reaction zone.
There was no steam or water injection during this test.
As shown on Table 6, a 61% 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.
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In this example, the feed rate was increased by 50% over the first two
examples, and there was no steam or water
injection. Although the conversion of heavy oil is lower than in the first two
examples, 61% of the 350 C' 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: performed on the same kiln but with a different oil sample.
Please refer to the Table 4 - Example 4 for a summary of the operating
conditions and feed and products rates and
analyses.
Table 4 - Example 4
Reactor Size: L = 1.07 m, Diameter 0.47 m
Reactor Temperature: SW C
Reactor Pressure: 125KPa(a)
Sweep Gas: Steam @ 0.51% wt on dry oil feed
Heavy Oil Recycle: None
Oil Feed Rate: 6.7 L/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 D4052 g/ml 0.88 0.841 0.889 1.109 2.683
Molecular Weight g/mole 37
Water STM D1533 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 D445 cst 45.3 1.276
Copper Strip Corrosion ASTM D120
Sediments ASTM D2276 mg/ml 0.25
Flash Point ASTM D92 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 ASTM D2887 Weight %
IBP 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.
CA 02750129 2011-08-17
As shown on Table 6, a 79.5% conversion of the 350 CT fraction into lighter
oils, gas and coke was achieved.
The gasoil make was 70% wt., an increase of 57% of the feed oil. Over 95% of
the metals entering the reactor
exited with the coke.
Example 5: Performed on a larger kiln with oil similar to that used in example
4.
Please refer to the Table 5 - Example 5 for a summary of the operating
conditions and feed and products rates and
analyses.
Table 5 - Example 5
Reactor Size: L= 2.44 m; Diameter=3.05m
Reactor Temperature: 500 C
Reactor Pressure: 50 KPa(a) average
Sweep Gas: 0
Heavy Oil Recycle: 350 L/h
Oil Feed Rate: 1125 L/h
Test Method Units Feed Oil Gas Naphtha Gasoil HeavyOil Coke
& Solids
Weight%on Dry Oil Feed 100 2.6 7.6 51.7 35.2 2.9
Density @ 15C ASTM D4052 g/ml 0.897 0.751 0.846 0.876 1.8
Molecular Weight g/mole
Water STM D1533 Volume % 14.7
Metals (1) Digestion & ICP-IS ppm Weight 3650 2.4 1.4 10.3
Sulphur ASTM D808 Weight % 0.36 0.07 0.09
Halogens Oxygen Bomb Combustion ppm Weight 350 0.02 <3
Viscosity @ 40C ASTM D445 cSt 2.21
Copper Strip Corrosion ASTMD120 la
Sediments ASTM D2276 mg/ml 0.6 0 <0.01 0.009
Flash Point ASTM 093 C 42 51 214
MCRT ASTM D4530 Weight %
Ash ASTM D4422 & ASTM D482 Weight % 37.1
pH
Distillation ASTM D2887 Weight %
IBP C 91 39 134 318
10% C 295 77 173 429
50% C 421 114 269 481
90% C 499 19 370 539
EP C 571 182 422 689
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 first three examples, but comparable to the oil in
example 4. This test was carried out on a
larger kiln than for the previous examples.
A dewatered waste oil stream of 1125 L/h is injected in an indirectly fired
rotating kiln, containing metal shavings
at 500 C. The seals on the kiln did not pen-lit pressures above atmospheric in
the reaction zone. There was no
steam injected into the reactor during this test. The total heavy oil stream
of 350 L/h was recycled and added to
the reactor feed stream. The pressure in the reactor varied between 30 KPa(a)
and 90 KPa(a) and it was difficult
to keep the temperature stable.
As shown on Table 6, a 58.8% conversion of the 350 C+ fraction into lighter
oils, gas and coke was achieved.
The gasoil make was 51.7% wt., an increase of 39.7% wt, of the feed oil. Over
99% of the metals entering the
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CA 02750129 2011-08-17
reactor exited with the coke. The best separation of the coke from the vapours
exiting the reactor was achieved
during this test. Over 75% of the sulphur entering the reactor exited the
process with the coke.
Table 6
Heavy Oil Conversion and Gasoil Gain
Example 1 2 3 4 5 Other (1)
Heavy Oil - 350C+
wt in Feed oil 74 74 73 83 85 84
% wt in Products 20.6 22.6 29 17 35 9
1% Conversion 72.2 69.5 61 79.5 58.8 86.9 (2)
Gasoil - 185C to 350C
% wt in Feed oil 26 26 26 13 12 12.5
% wt in Products 56.5 46.8 54 700 51.7 63.2
%0 wt Gain on Feed oil 30.5 20.8 28 57 39.7 50.7
Notes: 1) "Other" is the average obtained by operating the larger
kiln over 5,000 hours with between 0 and 10% wt. (on dry
oil feed) steam injection.
2) During these runs, about 30% of the heavy oil make was
recycled back to the reactor feed.
The average results from some 5,000 hours of subsequent runs on this kiln are
shown in the "other" column of
Table 6. They achieved an average 86.9% conversion of the heavy oil fraction
entering the reactor in the dry
waste oil feed. The wide range diesel oil fraction in the feed oil of 12.5%
wt. became 63.2% wt. at the reactor
exit, an increase of 50.7% wt. on dry oil feed.
Some embodiments of the invention may have only one of these advantages; some
embodiments may several
advantages and/or may have all of them 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).
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Depending on the sulphur content in the feed oil, the sulphur in the diesel
produced could be below the 0.1 % wt.,
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 from their feedstock 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 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 mostly
attached to the coke when exiting the
reactor. 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 asphalts or
cements as a water-repelling additive.
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, the 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.
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.
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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;
- a 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;
- no by-products to dispose of in industrial landfills;
- less need for the purchase of chemicals and disposal of spent chemicals;
- a steady and controllable reaction pressure, and
- minimizing of the thermal stress on the reactor walls and/or on the
internals.
This waste oil thermal cracking process has many advantages over other waste
oil cracking or reuse processes:
- it is simple and easy to operate;
- it is flexible and can treat a wide variety of waste oils, not just used
lubricating oils from service stations
and the like;
- 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;
- 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;
- 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;
- 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;
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CA 02750129 2011-08-17
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; and
- it is viable in smaller plants, with a smaller collection radius and does
not need to be subsidized by
governments.
Some embodiments of the invention may have only one of these advantages; some
embodiments may several
advantages and may have all of simultaneously.
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.
