Note: Descriptions are shown in the official language in which they were submitted.
1
TITLE:
Combined process to produce both a pipelineable crude and carbon fiber from
heavy hydrocarbon
Field of the Invention:
The invention disclosed and claimed has to do with processing of heavy
hydrocarbon
feedstock such as Canadian bitumen (but any heavy hydrocarbon) to upgrade the
feedstock to marketable and transportable products, such as blended crude oil
suitable for transport by pipeline and value-added carbon fibre or carbon-
fibre
precursor materials. The invention is a type of hydrocarbon upgrading process
or
system.
PRIOR ART:
The following discussion is meant to inform the reader of the state of the art
in the
realm of this invention.
U.S. patent 4,454,023 discloses a method that thermally cracks a heavy crude
and
solvent deasphalts the residue into a liquid pitch using a solvent process. A
lower
yield pipelineable crude product is created and the process creates a liquid
phase
asphaltene by-product that is then sent to a gasifier for combustion purposes.
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U.S. patent 4,572,281 provides a process to generate solid asphaltenes post-
solvent
deasphalting from heavy hydrocarbon. The generation of the solid asphaltenes
occurs at a different point in the process, the asphaltene solids are
considered for
combustion, and there is no mention of a pipelineable crude as a product.
U.S. patents 9,200,211 and 9,150,794 both disclose a method to generate
pipelineable crude while producing a solid asphaltene product that is
generated as a
solid in the mixing portion of the solvent deasphalting step. However, these
patents
do not address anything beyond solid asphaltene products made in concert with
the
pipelineable heavy crude, and simply teach that the solid asphaltene material
is good
for use in combustion processes like gasification and for power production.
U.S. Patent 7,101,499 shows an apparatus for producing pellets from hot heavy
hydrocarbon or asphaltene that supplies the hot heavy hydrocarbon or
asphaltene
through a conduit to its outlet; and pellet producing medium or means that
breaks up
the liquid stream of the hot asphaltene flowing out of the outlet of the
conduit and
produces pellets of asphaltene. The feedstock in this patent is a liquid
asphaltene
teaching away from the a solid being fed to the extruding step.
U.S. patent application 2013/0036714 is a continuous process for fractioning,
combining, and recombining asphalt sources into asphalt components for
pelletization of asphalt and asphalt-containing products such that the pellets
formed
are generally uniform in dimension, freely flowing, free from agglomeration,
and the
pelletized asphalt is dried and/or packaged, and preferably compatibly
packaged, for
additional processing and applications. This patent requires a pre-pelletizing
process
(i.e. filtering) and a drying and/or packaging step. Also, the patent refers
to the Asphalt
as a solid or liquid requiring filtering and heating/cooling to obtain the
necessary
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viscosity and consistency for feed to the pelletizer. The feedstock to the
transport
preparation step (i.e pelletizing) is essentially a liquid (with a softening
point) teaching
away from a solid particulate asphaltene product being generated in the
asphaltene
removal step.
U.S. patent 9,580,839 makes carbon fiber from asphaltenes obtained from heavy
oil
feedstocks undergoing upgrading in a continuous coking reactor. The liquid-
phase
asphaltene stream is mixed as the asphaltene stream travels horizontally from
a first
end of a continuous coking reactor. The process then takes the liquid-phase
asphaltene stream through a filter to yield a purified asphaltene stream;
introducing
the purified asphaltene stream through a spinneret to yield carbon-based
filaments;
passing the carbon-based filaments through an inert gas stream to yield a
carbon-
based fiber; and collecting the carbon-based fiber on a draw-down device. The
patent
teaches away from using solid asphaltenes, as the feed to the spinneret is a
liquid,
and in addition does not produce a pipelineable crude from the process.
Applicant has found no patents or literature that disclose a common base
process to
treat or upgrade a heavy hydrocarbon to produce two higher valued products
that
include a pipelineable heavy crude and a carbon fiber and/or activated carbon.
SUMMARY OF THE INVENTION:
It is to be understood that other aspects of the present invention will become
readily
apparent to those skilled in the art from the following detailed description,
wherein
various embodiments of the invention are shown and described by way of
illustration.
As will be realized, the invention is capable for other and different
embodiments and
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its several details are capable of modification in various other respects, all
without
departing from the spirit and scope of the present invention. Accordingly, the
drawings and detailed description are to be regarded as illustrative in nature
and not
as restrictive.
In an embodiment, an integrated process is provided to produce both a
pipelineable
crude and a carbon fiber product from a common heavy hydrocarbon feedstock,
where the feedstock is first processed in a thermal reactor and some of the
product
from the reactor is treated in a solvent deasphalting unit, with produced
liquids
lo being collected and mixed and further processed to reduce olefins, to
produce a
liquid crude stream for pipeline transport. From the same reactor product,
asphaltene solids are also produced from the solvent deasphalting unit, and
then
further processed into a carbon fiber product, and gases generated at any
portion of
the entire process may be reused in the process or sold. This embodiment
features
the following specific ordered process steps:
a. Introducing heavy hydrocarbon feedstock to a heater and raising the
feedstock's temperature to a desired range below the cracking
temperature of the feedstock (600-660 F (315.6-348.9 C));
b. Sending the heated heavy hydrocarbon feedstock for processing to in
a near atmospheric thermal reactor operating at an elevated uniform
bulk liquid temperature of 700-790 F (371.1-421.1 C) for an in-reactor
residence time (1 min to 7 hours) to create and produce a vaporized
lighter heavy hydrocarbon stream from the reactor and a separate
heavier liquid hydrocarbon stream from the reactor;
c. Condensing the lighter hydrocarbon stream produced from the reactor
in step b);
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d. Saturating olefins in the condensed lighter hydrocarbon stream from
step c);
e. Mixing the heavier liquid hydrocarbon stream produced in step b) with
a lighter hydrocarbon which acts as a solvent to precipitate asphaltene
solid particulate (powder) which is and remains solid at operating
conditions, creating and producing a solid/liquid mixture;
f. Separating the solid/liquid mixture produced in step e) into two
streams: a solid/solvent slurry and a second heavy hydrocarbon liquid
(resin)/solvent mixture;
g. Separating the heavy hydrocarbon liquid (resin)/solvent mixture
produced in step f) into a heavy hydrocarbon stream and a solvent
stream for reuse as required in process step e)
Ii. Mixing the heavy hydrocarbon stream produced in step g) with the
condensed lighter hydrocarbon stream produced in step d) to create a
pipelineable crude;
i. Separating solids from solvent in the solid/solvent slurry produced in
step f) in a solid/vapor inertial separation unit, to produce a solvent-
free solid asphaltene particulate (powder) stream and a vaporized
solvent stream where the vaporized solvent is then condensed and
reused as required in step e);
j. Adding a different solvent to the solid asphaltene powder in step i) to
create and produce a reduced solid stream primarily consisting of
coke, coke precursors and inorganic material and a second stream
being a mixture comprised of the added different solvent and a
reduced asphaltene solid particulate with coke, coke precursors and
inorganic material removed;
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k. Separating the solvent/asphaltene mixture produced in step j) to
create and produce a stream of the different solvent which may be
reused as required in step j) and a reduced asphaltene solid
particulate stream;
I. Extruding the reduced asphaltene solid particulate produced in step k)
into non-Newtonian flowing fluid producing extruded asphaltenes;
m. Spinning the extruded asphaltenes into continuous thread that can be
wound on a spool;
n. Stabilizing the spooled asphaltene thread by heat treatment at 350-
550 F (176.7-287.8 C) for up to 1 hour;
o. Carbonizing the stabilized asphaltene thread by heat treatment at
1832-3632 F (1000-2000 C) for up to 1 hour to produce a carbonized
carbon fiber; and
p. Adding surface treatment and sizing the carbonized carbon fiber to
create a general purpose carbon fiber product.
In another embodiment, the process has an additional intermediate process step
before step j) to produce a higher quality carbon fiber with the following
qualities:
Tensile strength of at least 1.5 GPa; and
Young modulus of at least 290 GPa,
the added process being an additional solvent separation step to remove
insolubles
from the asphaltene powder solids in step i) which insoluble might hinder the
formation of "marketable" carbon fiber thread.
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In another embodiment of the process an additional step of flash separation,
preferably under partial vacuum, is performed to remove lighter molecules from
the
asphaitenes before step j) in order to reduce the production of voids in the
carbon
fiber thread.
An additional step of graphitization may be added in yet another embodiment of
the
process after step m) to heat the carbon fiber to over 5432 F (3000 C) to
produce a
graphene product.
lo Another embodiment of the process includes an additional thermal
cracking step
after step b) but before step e) to generate more mesophase material to
improve
the characteristics of the carbon fiber product.
An apparatus is provided in an embodiment of the invention to perform the
steps of
the above process as an integrated process to create both a pipelineable crude
and
a carbon fiber product from a single crude feedstock. The apparatus includes:
a. Means to introduce heavy hydrocarbon feedstock to a heater to be
raised to a desired temperature range below the cracking temperature
of the feedstock (600-660 F (315.6-348.9 C));
b. Means to send and process the heated heavy hydrocarbon feedstock
in a near atmospheric thermal reactor operating at an elevated
uniform bulk liquid temperature of 700-790 F (371.1-421.1 C) for a
desired residence time of between 1 min to 2 hours to produce a
vaporized lighter heavy hydrocarbon stream from the reactor and a
separate heavier liquid hydrocarbon stream from the reactor;
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c. Means to receive and condense the lighter hydrocarbon stream in
produced in b);
d. Means to saturate the olefins in the condensed lighter hydrocarbon
stream condensed in c);
e. Means to mix the heavier liquid hydrocarbon stream produced in b)
with a different lighter hydrocarbon acting as a solvent to precipitate
asphaltene solid powder at operating conditions creating a solid/liquid
mixture;
f. Means to separate the solid/liquid stream produced in e) into two
io streams, one a solid/solvent slurry, and a second heavy
hydrocarbon
liquid/solvent mixture;
g. Means to separate the heavy hydrocarbon liquid/solvent mixture
produced in f) into a heavy hydrocarbon stream and a solvent stream
that can be reused in e);
h. Means to mix the heavy hydrocarbon stream from g) with the lighter
hydrocarbon stream from d) to create a pipelineable crude;
i. Means to separate the powder solids from the solvent in the
solid/solvent slurry produced in f) in an inertial separation unit,
creating a solvent-free solid asphaltene powder stream and a
vaporized solvent stream where the solvent may be further condensed
and reused in e);
j. Means to add a different solvent to the solid asphaltene powder in i) to
create a reduced solid stream primarily consisting of coke, coke
precursors and inorganic material and a second stream comprised of
the added solvent and asphaltene solid mixture;
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k. Means to separate the solvent/asphaltene mixture to create a re-
usable stream of solvent for use in j) and a reduced asphaltene solid
stream;
I. Means to extrude the asphaltene solids produced in k) into a non-
Newtonian flowing fluid producing extruded asphaltenes;
m. Means to spin the extruded asphaltenes into a continuous thread that
can be wound on a spool;
n. Means to stabilize the asphaltene-based thread at 400-500 F (204.4-
260 C) for up to an hour;
o. Means to carbonize the stabilized asphaltene thread at 1832-3632 F
(1000-2000 C) for up to an hour; and
p. Means to add surface treatment and size the carbonized asphaltene-
based carbon fiber to create a marketable general purpose carbon
fiber product.
The apparatus may also include an additional solvent separation means to
remove
insolubles from the asphaltene powder solids from i) that might hinder
formation of
"marketable" carbon fiber thread; similarly, the apparatus may include means
to
provide an additional step of flash separation, preferably under partial
vacuum, to
remove lighter molecules from the asphaltenes to reduce the formation of voids
in
the carbon fiber thread. Additional means to provide graphitization may be
added
after step m) for heating the carbon fiber to over 5432 F (3000 C) to produce
a
graphene product, and means to provide an additional thermal cracking step may
be included after b) but before e) to generate more mesophase material to
improve
the characteristics of the carbon fiber product.
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An integrated process is provided which is operated to create both a higher
value
pipelineable crude and a high value carbon fiber product from a lower value
common heavy hydrocarbon feedstock such as bitumen, where the feedstock is
processed in a thermal reactor followed by a deasphalting step in a solvent
deasphalting (SDA) unit, with liquids produced in the reactor and SDA being
gathered and processed to reduce olefins and blended to make a crude liquid
product for pipeline transport, and with the asphaltene solids produced from
the
SDA being processed to generate a marketable carbon fiber product, and with
any
gases generated throughout the entire process reused in the process or sold.
Pipelineable crude is defined as a crude that meets current pipeline
specifications
of greater than API 19 (density <920 kg/m3), viscosity less than 300 cSt at
reference temperature, sediment and water less than 0.5 wt% and olefins less
than
1 wt% or non-detectable by the measurement tool used by the transporter.
Carbon fiber is defined as a fiber containing at least 92 wt % carbon. Carbon
fibers
generally have excellent tensile properties, low densities, high thermal and
chemical
stabilities in the absence of oxidizing agents, good thermal and electrical
conductivities, and excellent creep resistance. They have been extensively
used in
composites in the form of woven textiles, continuous fibers/rovings, and
chopped
fibers for making manufactured goods. The composite parts can be produced
through filament winding, tape winding, pultrusion, compression molding,
vacuum
bagging, liquid molding, and injection molding. This process creates both a
pipelineable crude and commercial quality carbon fiber product.
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In one aspect, there is provided an integrated process is provided to produce
both a pipelineable
crude product and a carbon fiber product from a heavy hydrocarbon feedstock,
where the heavy
carbon feedstock is processed in a thermal reactor and some of the product
from the thermal
reactor is treated in a solvent deasphalting unit, with produced liquids being
collected and mixed
and further processed to reduce olefins, to produce a liquid crude stream for
pipeline transport,
and with asphaltene solids produced from the solvent deasphalting unit further
processed into
the carbon fiber product, and where gases generated at any portion of the
entire process are
reused in the process or sold, the process comprising:
a. introducing the heavy hydrocarbon feedstock into a heater and raising
the heavy
hydrocarbon feedstock temperature to a desired temperature range below a
cracking temperature of the heavy hydrocarbon feedstock of 600-660 Fto
produce a heated heavy hydrocarbon feedstock;
b. sending the heated heavy hydrocarbon feedstock for processing to a near
atmospheric thermal reactor operating at an elevated uniform bulk liquid
temperature of 700-790 F for an in-reactor residence time of 1 min to 7 hours
to
create and produce a vaporized lighter heavy hydrocarbon stream and a heavier
liquid hydrocarbon stream;
c. condensing the lighter hydrocarbon stream produced from the reactor in
step b)
to produce a condensed lighter heavy hydrocarbon stream;
d. saturating olefins in the condensed lighter hydrocarbon stream from step
c) to
produce a condensed olefin-saturated liquid;
e. mixing the heavier liquid hydrocarbon stream produced in step b) with a
lighter
hydrocarbon solvent to precipitate asphaltenes and form a precipitated
asphaltene solid particulate which remains solid at operating conditions,
creating
and producing a solid/liquid mixture;
f. separating the solid/liquid mixture produced in step e) in two streams
including a
solid/lighter hydrocarbon solvent slurry and a heavy hydrocarbon
liquid/lighter
hydrocarbon solvent mixture;
Date Recue/Date Received 2022-09-12
10b
g. separating the heavy hydrocarbon liquid/lighter hydrocarbon solvent
mixture
produced in step f) into a heavy hydrocarbon stream and a lighter hydrocarbon
solvent;
h. mixing the heavy hydrocarbon stream produced in step g) with the
condensed
olefin-saturated liquid produced in step d) to create the pipelineable crude
product;
separating solids from the lighter hydrocarbon solvent in the solid/lighter
hydrocarbon solvent slurry produced in step f) in a solid/vapor inertial
separation
unit, to produce a solvent-free solid asphaltene particulate stream and a
vaporized lighter hydrocarbon solvent stream;
j. adding a first solvent different from the lighter hydrocarbon solvent to
the solvent-
free solid asphaltene particulate stream in step i) to produce a reduced solid
stream primarily consisting of coke, coke precursors and inorganic material
and
a second stream being an asphaltene solid particulate/solvent mixture
comprising the first solvent and an asphaltene solid particulate with coke,
coke
precursors and inorganic material removed;
k. separating the asphaltene solid particulate/solvent mixture of step j)
to recover
the first solvent for reuse in step j) and a reduced asphaltene solid
particulate
stream;
extruding the reduced asphaltene solid particulate stream to produce extruded
asphaltenes;
m. spinning the extruded asphaltenes into a continuous thread of asphaltene
thread
woundable on a spool;
n. stabilizing the asphaltene thread by heat treatment at 350-550 F for up
to 1 hour
to produce a stabilized asphaltene thread;
o. carbonizing the stabilized asphaltene thread by heat treatment at 1832-
3632 F
for up to 1 hour to produce a carbonized carbon fiber; and
Date Recue/Date Received 2022-09-12
10c
P. conditioning the carbonized carbon fiber to create the carbon
fiber product,
wherein the conditioning comprises surface treating and sizing the carbonized
carbon fiber.
In another aspect, there is provided an apparatus is also provided to produce
a pipelineable
crude and a carbon fiber product from a heavy hydrocarbon feedstock, the
apparatus
comprising:
a. a first heater configured to heat heavy hydrocarbon feedstock within a
desired
temperature range below the cracking temperature of the heavy hydrocarbon
feedstock of 600-660 F;
b. a near atmospheric thermal reactor in fluid communication with the first
heater,
the near atmospheric thermal reactor being configured for operation at an
elevated uniform bulk liquid temperature of 700-790 F for a desired residence
time of between 1 min to 7 hours to produce a vaporized lighter heavy
hydrocarbon stream and a heavier liquid hydrocarbon stream;
c. a first solvent deasphalting separator in fluid communication with the
near
atmospheric thermal reactor, the first solvent deasphalting separator being
configured to mix the heavier liquid hydrocarbon stream produced in b) with a
first lighter hydrocarbon solvent to precipitate asphaltenes solid and produce
a
solids/lighter hydrocarbon solvent slurry, and a heavy hydrocarbon
liquid/lighter
hydrocarbon solvent mixture, the heavy hydrocarbon liquid/lighter hydrocarbon
solvent mixture being further treatable to enable mixing with a condensed
olefin-
saturated liquid to create the pipelineable crude product;
d. an inertial separation unit in fluid communication with the first
solvent
deasphalting separator, the inertial separation unit being configured to
separate
solids from the first lighter hydrocarbon solvent in the solids/lighter
hydrocarbon
solvent slurry produced in c) and produce a solvent-free solid asphaltene
particulate stream and a vaporized lighter hydrocarbon solvent stream;
Date Recue/Date Received 2022-09-12
10d
e. a second solvent deasphalting separator for addition of a second solvent
different from the first lighter hydrocarbon solvent to the solvent-free solid
asphaltene particulate stream produced in d) to create a reduced solids stream
primarily consisting of coke, coke precursors and inorganic material and an
asphaltene solid particulate/solvent mixture comprising the second solvent and
an asphaltene solid mixture;
f. an extruder in fluid communication with the second solvent deasphalting
separator, the extruder being configured to separate the asphaltene solid
particulate/solvent mixture of e) to produce a reduced asphaltene solid
particulate stream and a recovered solvent stream recyclable to the first
solvent
deasphalting separator, and further configured to extrude the reduced
asphaltene solid particulate stream to produce extruded asphaltenes that are
spinnable into a continuous thread of asphaltene thread woundable on a spool;
9. a second heater configured to stabilize the asphaltene thread at
400-500 F for
up to 1 hour to produce a stabilized asphaltene thread; and
h. a furnace configured to carbonize the stabilized asphaltene
thread at 1832-
3632 F for up to 1 hour to produce a carbonized carbon fiber, the carbonized
carbon fiber being subjectable to a surface treatment to produce the carbon
fiber
product.
In another aspect, there is provided a process is provided to treat a heavy
hydrocarbon
feedstock, comprising: thermally treating the hydrocarbon feedstock at a
temperature ranging
from 700 F to 790 F for a residence time ranging from 1 minute to 7 hours to
produce a
lighter hydrocarbon stream and a heavier hydrocarbon stream; solvent
deasphalting the
heavier hydrocarbon stream with a solvent to precipitate asphaltenes and form
solid
asphaltene precipitates and produce deasphalted oil; separating the
deasphalted oil from the
solid asphaltene precipitates to produce a solvent - diluted deasphalted oil
stream comprising
at least a portion of the solvent and a slurry stream comprising the
asphaltene precipitates
and residual solvent; separating the solvent - diluted deasphalted oil stream
to produce a
recovered solvent stream and a deasphalted oil stream; and separating the
slurry stream to
Date Recue/Date Received 2022-09-12
10e
produce a solid asphaltene particulate stream and a recovered solvent stream,
the solid
asphaltene particulate stream being suitable as a carbon fiber precursor.
In another aspect, there is provided a system is provided for treating a heavy
hydrocarbon
feedstock, the system comprising: a thermal reactor configured to receive the
heavy
hydrocarbon feedstock and operable at a temperature ranging from 700 F to 790
F for a
residence time of between 1 min and 7 hours to produce a lighter hydrocarbon
stream and a
heavier hydrocarbon stream; a solvent deasphalting separator in fluid
communication with
the thermal reactor and configured to contact the heavier hydrocarbon stream
with a solvent
to precipitate asphaltenes and form solid asphaltene precipitates, the solvent
deasphalting
separator producing a solvent-diluted deasphalted oil stream comprising at
least a portion of
the solvent and a slurry stream comprising the asphaltene precipitates and
residual solvent;
and an inertial separation unit in fluid communication with the solvent
deasphalting separator,
the inertial separation unit being configured to separate the slurry stream
solids to produce a
solid asphaltene particulate stream and a recovered solvent stream, the solid
asphaltene
particulate stream being suitable as a carbon fiber precursor.
In another aspect, there is provided a process is provided for producing a
carbon fiber
product, comprising: thermally treating a hydrocarbon feedstock at a
temperature ranging
from 700 F to 790 F for a residence time ranging from 1 minute to 7 hours to
produce a
lighter hydrocarbon stream and a heavier hydrocarbon stream; solvent
deasphalting the
heavier hydrocarbon stream with a solvent to precipitate asphaltenes and form
solid
asphaltene precipitates and produce deasphalted oil; separating the
deasphalted oil from the
solid asphaltene precipitates to produce a solvent-diluted deasphalted oil
stream comprising
at least a portion of the solvent and a slurry stream comprising the
asphaltene precipitates
and residual solvent; separating the slurry stream to produce a solid
asphaltene particulate
stream and a recovered solvent stream; extruding the solid asphaltene
particulate stream to
produce extruded asphaltenes; spinning the extruded asphaltenes into a
continuous thread
of asphaltene thread; stabilizing the asphaltene thread by heat treatment at
350 F to 550 F
for up to 1 hour to produce a stabilized asphaltene thread; carbonizing the
stabilized
asphaltene thread by heat treatment at 1823 F to 3632 F for up to 1 hour to
produce a
Date Recue/Date Received 2022-09-12
10f
carbonized carbon fiber; and conditioning the carbonized carbon fiber to
produce the carbon
fiber product.
In another aspect, there is provided a process is provided for treating a
heavy hydrocarbon
feedstock, comprising: thermally treating the hydrocarbon feedstock to produce
a lighter
hydrocarbon stream and a heavier hydrocarbon stream; solvent deasphalting the
heavier
hydrocarbon stream with a solvent to precipitate asphaltenes and form solid
asphaltene
precipitates and produce deasphalted oil; separating the deasphalted oil from
the solid
asphaltene precipitates to produce a solvent-diluted deasphalted oil stream
comprising a
portion of the solvent and a slurry stream comprising the asphaltene
precipitates and residual
solvent; separating the solvent-diluted deasphalted oil stream to produce a
recovered solvent
stream and a deasphalted oil stream; separating the slurry stream to produce a
solid
asphaltene particulate stream and a recovered solvent stream; and processing
the solid
asphaltene particulate stream to produce a carbon fiber precursor.
In another aspect, there is provided a process is provided for treating a
heavy hydrocarbon
feedstock, comprising: solvent deasphalting the heavy hydrocarbon feedstock
with a solvent
to precipitate asphaltenes and form solid asphaltene precipitates and produce
deasphalted oil;
separating the deasphalted oil from the solid asphaltene precipitates to
produce a solvent-
diluted deasphalted oil stream comprising a portion of the solvent and a
slurry stream
comprising the asphaltene precipitates and residual solvent; separating the
solvent-diluted
deasphalted oil stream to produce a recovered solvent stream and a deasphalted
oil stream;
separating the slurry stream to produce a solid asphaltene particulate stream
and a recovered
solvent stream; and processing the solid asphaltene particulate stream to
produce a carbon
fiber precursor.
In another aspect, there is provided a process is provided for producing a
carbon fiber
precursor, comprising: solvent deasphalting a hydrocarbon feedstock with a
first solvent to
precipitate asphaltenes and form solid asphaltene precipitates and produce
deasphalted oil;
separating the deasphalted oil from the solid asphaltene precipitates to
produce a solvent-
Date Recue/Date Received 2022-09-12
1 Og
diluted deasphalted oil stream comprising a portion of the solvent and a
slurry stream
comprising the asphaltene precipitates and residual solvent; separating the
slurry stream to
produce a solid asphaltene particulate stream and a recovered solvent stream;
solvent
deasphalting the solid asphaltene particulate stream with a second solvent,
different from the
first solvent, to precipitate insolubles contained in the solid asphaltene
particulate stream;
separating the insolubles from the solid asphaltene particulate stream; and
processing the
solid asphaltene particulate stream to produce the carbon fiber precursor.
Date Recue/Date Received 2022-09-12
11
BRIEF DESCRIPTION OF DRAWINGS:
FIG. 1 is a block diagram or flow-chart of the integrated process of the
invention.
FIG. 2 is a block diagram or flow-chart of a second embodiment of the
integrated
process of the invention.
DETAILED DESCRIPTION:
The detailed description set forth below in connection with the appended
drawings is
intended as a description of various embodiments of the present invention and
is not
intended to represent the only embodiments contemplated by the inventor. The
detailed description includes specific details for the purpose of providing a
comprehensive understanding of the present invention. However, it will be
apparent
to those skilled in the art that the present invention may be practiced
without these
specific details.
Figure 1 is a process flow diagram depicting a process 10 for forming a
hydrocarbon
liquid product 200, that meets pipeline specification and a carbon fiber
product 120
from a common heavy hydrocarbon feedstock 5 that cannot itself be shipped by
pipeline without treatment or modification. The final hydrocarbon product 200
has
sufficient characteristics to meet minimum pipeline transportation
requirements
(minimum API gravity of 19, at least 350 cSt at 7.5 oC, less than 0.5wt%
sediment
and water and olefins less than 1wt% (or non-detectable)) and is a favourable
refinery
feedstock while the final solid product 120 has sufficient characteristics to
be used in
general purpose and high performance carbon fiber products. Process10 is
designed
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to use over 95wt% of the heavy hydrocarbon feedstock with over 83wr/o used as
a
pipelineable crude and over 12wt% as carbon fiber.
As shown in Figure 1, a heavy hydrocarbon feedstock 5, that can't be shipped
via
pipeline, can be routed through a heater 20 to heat the material to a desired
temperature level and sent as stream 25 to a reactor 30 where the process
fluid
temperature is controlled and maintained while it undergoes a mild controlled
cracking process. Sweep gas, 31, can be introduced into the reactor to assist
in
mixing the liquid pool in the reactor and to assist in removing any evolved
vapours
lo from the hydrocarbon feedstock. The sweep gas can be any type of non-
condensable
vapour that can end up in the fuel gas system for combustion or reuse in the
process.
Examples of sweep gas can be a hydrocarbon mixture such as natural gas or
steam,
nitrogen or hydrogen. After the mild cracking process, a light top fraction 33
can be
routed from the reactor 30 to a gas liquid condensing separator and olefin
saturation
process 40 with a heavy bottom fraction 32 routed to a liquid/solid solvent
extraction
process 50. The condensed overhead liquid fraction 33 will have a much higher
API
gravity than the bottom fraction 32. For example, the overhead liquid fraction
33 could
typically have an API gravity of 26 or greater.
An olefin saturation process 40 takes the vapour stream 33 from the reactor 30
to
convert the olefins in this stream to meet pipeline transport specification.
The
condensed olefin-saturated liquid exits unit 40 as stream 45 and can be
blended into
the final product, 200. Any non-condensable vapour exits as stream 43 and can
be
sent to an H2S removal unit, such as an amine unit, so vapour can be readily
reused
in the process or used as a fuel gas.
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Stream 32 from the reactor 30 is fed to the solvent deasphalting unit 50. The
solvent
extraction process 50 can comprise any suitable solvent extraction process
that can
handle the separation of precipitated solids at operating conditions from the
remaining hydrocarbon liquid. An example of a relevant solid-liquid solvent
separation
process is US patent 9,976,093 and Canada patent 2,844,000. A recycled solvent
stream 63, 73 may be mixed with stream 32 to precipitate a solid asphaltene
phase
from the liquid 32 stream. Additional makeup solvent may be required to mix
with
stream 32 in separator 50. The asphaltenes precipitated are a solid powder so
a
solid/liquid separation can now be made as opposed to the typical
liquid/liquid
separation. A solid/liquid separation requires less solvent to provide the
desired
recovery of pipelineable heavy oil. A heavy deasphalted oil leaves the SDA
unit, 50,
as stream 57, Stream 57 is blended with stream 45 to create the final product,
200,
which has physical characteristics which enable it to meet required pipeline
transport
criteria without having to mix the final hydrocarbon with transport diluents,
The solvent
used in SDA 50 can be a pure hydrocarbon component ideally in the range of C6
to
C8 or more practically, a mixture of C5 to C8 extracted from readily available
natural
gas condensate or diluent that comes in with the heavy crude feed.
Stream 53 contains entrained solid asphaltene powder in a solvent liquid
phase.
Stream 53 is reduced in pressure to flash the solvent to create a vapor/solid
mixture
as a slurry or suspension that enters the inertial separation unit (ISU), 60,
for a
solid/vapour separation. Solvent vapour is condensed and returned to the SDA
unit
50 for reuse as stream 63. The asphaltene solid powder leaves the ISU as
stream 67
and enters an extruder to apply pressure to the solid asphaltenes to remove
any
remaining entrained solvent. The extruder temperature can be in the 200-350 C
range to create conditions to provide continuous flow as a Non-Newtonian fluid
through and out of the equipment. The removed solvent is returned to the SDA
unit
as stream 73. Some of the generated asphaltene extrudate can be segregrated
and
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sent to the solid fuels market, as stream 71, if the market for carbon fiber
is saturated
or not economic. As another embodiment, material in stream 71 can be sent to
for
processing to become activated carbon. The majority of the extruded
asphaltenes
leave the extruding unit, 70, as stream 75 and is fed to the spinning unit,
80, where
"green" carbon fiber is produced as stream 85. "Green" fiber is a term used
for
hydrocarbon crude derived fiber that has yet to be oxidized or carbonized, and
is
extremely fragile.) The spinning of the "green" fiber can be accomplished by
either
melt or jet spinning. Ideally, the diameter of the "green" fiber is less than
15 urn,
preferably less than 10 urn for commercial applications.
The "green" fiber is then stabilized in unit 90. Stabilization is accomplished
by heating
the fibers in a forced air environment to provide sufficient fresh oxygen to
the fiber
surfaces air at temperatures in the range of 200-300 C. Heating causes the
spun
fibers to pick up oxygen molecules on their surfaces to prevent the onset of
inter-fiber
coalescence or melting and to promote good carbon yield in later
carbonization.
Stabilization can take between a few minutes up to an hour or two. The
stabilized
fiber, stream 95, is then carbonized, in unit 100, under an inert environment
(no
oxygen) and is heated uniformly up to approximately 1000 C, but can go up to
1800 C
to improve both the fiber strength and Young modulus. The carbonizing step can
take
between a minute to up to an hour or two depending on the final properties
desired.
The lack of oxygen prevents the fibers from burning in the very high
temperatures.
As the fibers are heated, they begin to lose their non-carbon atoms, plus a
few carbon
atoms, in the form of various gases including water vapor, ammonia, carbon
monoxide, carbon dioxide, hydrogen, nitrogen, sulfur, evolved metals such as
nickel
and vanadium and others. As the non-carbon atoms are expelled, the remaining
carbon atoms form tightly bonded carbon crystals that are aligned more or less
parallel to the long axis of the fiber. In a variant of this process, two
furnaces operating
at two different temperatures are used to better control the rate of heating
during
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carbonization. The carbonized fiber leaves as stream 108 and can have surface
treatment and sizing applied in unit 110. Surface treatment and sizing methods
mainly
used are acid oxidation, resin addition, plasma treatment, rare earth
treatment, and/or
gamma irradiation. Surface treatment leads to improved composite properties
due to
the conditions of improved surface area of the fiber surface, chemical bonding
and
adhesion between fiber and matrix. Surface treating and sizing is typically
used since
after carbonizing, the fibers have a surface that does not bond well with
epoxies and
other materials used in composite materials. To give the fibers better bonding
properties, their surface is slightly oxidized. The addition of oxygen atoms
to the
surface provides better chemical bonding properties and also etches and
roughens
the surface for better mechanical bonding properties. Oxidation can be
achieved by
immersing the fibers in various gases such as air, carbon dioxide, or ozone;
or in
various liquids such as sodium hypochlorite or nitric acid. The fibers can
also be
coated electrolytically by making the fibers the positive terminal in a bath
filled with
various electrically conductive materials. The surface treatment process must
be
carefully controlled to avoid forming tiny surface defects, such as pits,
which could
cause fiber failure.
The final carbon fiber product, stream 120, is normally general purpose (GP)
carbon
fiber. This product, 120, has a higher value than either the hydrocarbon
feedstock, 5,
or the typical disposition for asphaltenes, as a solid fuel.
As an additional embodiment to Figure 1, After the surface treatment, the
fibers can
be coated to protect them from damage during winding or weaving. This process
is
called sizing. Coating materials are chosen to be compatible with the adhesive
used
to form composite materials. Typical coating materials include epoxy,
polyester,
nylon, urethane, and others.
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The coated fibers are wound onto cylinders called bobbins. The bobbins are
loaded
into a spinning machine and the fibers are twisted into yarns of various
sizes.
Another embodiment, shown in Figure 2 provides modification options to the
process
shown in Figure 1 and described above in order to create an option for
production of
high performance carbon fibers along with general purpose carbon fiber and
pipelineable crude. Unit 35 can be added to provide additional thermal
cracking to
the residue portion of the crude to generate more mesophase material from the
thermally affected asphaltene solid powder for the feed to the SDA, 50, as
stream 37.
Mesophase content is a contributor to high performance carbon fiber.
Unit 65 can be added to perform further treatment and separation of the
asphaltene
solids. Stream 64 is undesirable solids that hinder the generation of carbon
fiber
while stream 66 contains flowable hydrocarbon that create voids in the carbon
fiber.
The material in stream 66 can be added to the hydrocarbon liquid product
stream,
200, if the pipeline specifications can be maintained. Otherwise, stream 66
can be
recycled to unit 30 for re-processing. Stream 64 can contain coke particles
generated
in reactor 30 and/or inorganic material in the feed. Unit 65 can contain a
second
solvent deasphalting step using organic solvents that adsorb heavier molecules
than
what is used in SDA unit, 50. The solvents that could be used to reject the
heaviest,
most undesirable solids in the solid asphaltene powder mixture are essentially
heterocyclic hydrocarbon based compounds such as toluene, xylene, benzene,
tetrahydrofuran, cyclohexanone, quinoline and pyridine among others. Vacuum
distillation can also be used in unit 65, alone or in combination with a
second
deasphalting step, to remove any remaining lighter molecules that could create
voids
in the carbon fiber. Any lighter material evolved in the vacuum distillation
or similar
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process will end up as stream 66. In addition, sparging can be considered
within unit
65 to produce more mesophase material by removing lighter components and
altering
the orientation of the carbon molecules to promote high performance carbon
fiber in
stream 130. Sparging is a process similar to air blowing, and for carbon
fiber, it is
normally conducted with inert nitrogen instead of air.
Carbon fibers can be graphitized in unit 105 after carbonization in unit 100
at
temperatures close to 3,000 C in an non-oxygen environment for improved
Young's
modulus. This step can create high performance carbon fibers with tensile
strength
above 1.5 GPA (preferably above 3 GPa) and Young's modulus above 290 GPA, up
to 500 GPa, Stream 103 from unit 100 is directed for graphitization in unit
105, while
stream 101 is directly set to the final step of surface treatment to create
general
purpose carbon fiber. The material leaving unit 105, graphitization, as stream
108,
will be high performance carbon fiber, stream 130, after surface treatment is
performed in unit 110.
In one aspect, the feedstock 5 can be a heavy hydrocarbon (virgin or a
previously
processed stream), such as the heavy hydrocarbon obtained from a SAGD (steam
assisted gravity drainage) process, for example Canadian Oil sands bitumen, or
from
any other suitable source of heavy hydrocarbon. In another aspect, the
feedstock 5
can have an API gravity in the range of 0 to 14.
The thermal cracker, 30, in Figure 1 and 30 and 35 in Figure 2, is operated at
conditions that maximize the economic return for producing both pipelineable
crude,
200, and carbon fiber products, 120 and 130. In one aspect, the heater 20 will
heat
the process fluid 5 to a temperature between 675-790 F (357.2-421,1 C). before
the
process fluid 25 is introduced into the reactor 30. In the reactor 30, the
process fluid
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25 (heated to 675-790 F (357.2-421.1 C) by the heater 20) undergoes a mild
controlled cracking process. Appropriately located heaters are provided in
this
reactor 30 to maintain the desired constant temperature generated in heater 20
and
to apply uniform heat flux for the fluid. The heaters provide indirect heat
through any
source readily available (electric, heat transfer fluid, radiant etc.). To
ensure a
uniform heat flux, mixing can be applied to the process fluid on a continuous
or
intermittent basis.
The reactor 30 can be operated in a manner, through optimizing primarily five
inter-
1.0 related process variables (Temperature, Pressure, Residence Time, Sweep
Gas and
Heat Flux), so as to reduce or even prevent coke from forming during the
reaction,
and minimizing gas production, while also providing optimal conversion of the
asphaltene portion of the heavy hydrocarbon to provide the desired mix of
refinery-
ready feedstock components through pipelineable crude and carbon fiber
products.
The first and second variables involve applying a uniform heat flux between
7000-
12000 BTU/hr sq.ft (22.1- 37.8KVV/m2) to the entire pool of process fluid in
the reactor
and maintaining a single operating temperature in the reactor between 675-790
F
(357.2-421.1 C). This may be achieved by the presence of appropriately sized
and
located heating devices in the reactor. The number of heaters will be set by
calculating the optimal dispersion of heat between any two heaters so as to
have a
uniform temperature throughout the pool and to avoid peak or spot temperatures
significantly higher than the target temperature in the reactor. Avoiding peak
temperature spots reducing the chance for generating coke in the reactor.
The third reactor variable, residence time, can be between 5 up to 7 hours
minutes
in the reactor. AS the residence time is increased, the conversion of 975-F F
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(523.9+ C) material to 975- F (523.9-F C) material increases and the expected
concentration of mesophase material increases.
The fourth reactor variable, operating pressure, can be maintained at near
atmospheric pressure, in any case, to be less than 50 psig (345 kPa), with
standard
pressure control principles used for consistent performance. The pressure
range is
controlled on the low end to prevent excessive, premature flashing of
hydrocarbon,
essentially bypassing the reactor, and limited on the high end to reduce
secondary
cracking and consequent increased gas yields.
The fifth reactor variable, sweep gas 31, may be added to the process fluid in
the
reactor 30 in the range of 0-80 set/bbl (0-14.24 Sm3/Sm3) if deemed beneficial
to
improving the reactor performance.
is The sweep gas 31 can be natural gas, hydrogen, produced/fuel gas from
the process,
steam, nitrogen or any other non-reactive, non-condensable gas that will not
condense to a liquid.
Sweep gas in the dosage of 0-80 scf/bbl (0-14.24 Sm3/Sm3) of feed may be
provided
to remove the "lighter" hydrocarbon products (i.e. methane to <750 F (398.9
C))
boiling point hydrocarbons) as soon as they are formed in the reactor 30 so
that there
is a minimum of secondary cracking which could increase gas make and
potentially
increase olefinic naphtha/distillate production. The sweep gas may also allow
the
reactor to operate closer to the desired operating pressure (<50 psig (345
kPa)) and
temperature. The sweep gas 31 can also be used to provide additional heat
and/or
mixing to the process fluid 14 in the reactor 30.
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Each variable may be changed independently, within the ranges suggested, based
on the quality of feedstock provided or based on the quality and quantity of
each
output desired. Since the 5 noted process variables are inter-related, a multi-
variable
process control scheme with a prescribed objective function (maximum yield to
meet
minimum product specifications) will be beneficial to ensure the process
operates at
an optimal point when any one of the variables is changed or the feed/product
situation is altered.
The overhead fraction 32 can be directed to a gas liquid separation unit 40,
which
can comprise a cooler and separation drum, as an example, in which a portion
of the
overhead fraction 32 that is a condensable liquid product containing naphtha
and
heavier hydrocarbons can be separated from the gaseous components of the
overhead fraction 32. An off-gas line 43 containing undesirable gases such as
sour
.. gas, can be provided at the separation drum in unit 40 (not shown) for
those gases
to be disposed of, recycled, or subjected to further treatment.
One or more liquid hydrocarbon streams can be produced from separation drum
(not
shown, but in 40).
The bottom fraction 32 can contain hydrocarbons, and thermally modified
asphaltenes. Although the characteristics of the bottom fraction 32 taken from
the
reactor 30 will vary depending on the process fluid 25 input into the reactor
30 and
the reactor's operating parameters, in one aspect the bottom fraction 32 can
have an
API gravity ranging between -5 and 5.
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Controllable process variables allow an operator to vary the performance of
the
reactor 30 to meet the needs of the final product based on changing
characteristics
of the incoming process fluid 25.
The controllability of the five inter-related variables, residence time, sweep
gas, heat
flux, temperature and pressure in the reactor 30 allow an operator to vary the
performance of the reactor 30.
In this manner, when the characteristics of the feedstock 5 are changed the
five inter-
related process variables can be optimized to avoid the production of coke and
minimize the production of non-condensable vapors which are produced in the
reactor 30. For example, the operator can vary the residence time of the
process
fluid in the reactor 30 based on the characteristics of the process fluid to
obtain the
desired yields and/or quality of the bottoms output 32, and the overhead
output, 33.
Alternatively, the operator can vary the sweep gas, temperature or pressure to
achieve similar outcomes.
The process variables are inter-related and the
minimization of coke and avoidance of excess gas make is challenging and is
best
determined by pilot operations.
The reactor 30 is operated in a manner that significantly limits and even
prevents the
formation of coke and reduces gas production while converting asphaltenes into
more
suitable components for downstream processing.
Consequently, modified
asphaltenes and other heavy components remain in the bottom fraction 32 that
is
removed from the reactor 30. To maximize the recovery of the desirable
refinery
feedstock crude and to separate heavy components for carbon fiber production,
the
bottom fraction 32 from the reactor 30 must be further treated using, for
example, a
high performance solvent extraction process 50. The treatment of the bottom
fraction
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32 by solvent extraction process 50 allows the reactor 30 and the solvent
extraction
process 50 to be used in conjunction, to produce a suitable full range
refinery
feedstock crude transported via pipeline without the need for transport
diluent and a
solid asphaltene product for carbon fiber production which can involve the
following
steps: extrusion, melt spinning, stabilization, carbonization, graphitization,
surface
treatment, and/or sizing. As stated previously, optional thermal conditioning
in Unit
35, and optional solvent deasphalting in Unit 55, can be employed to generate
different quality crude and carbon fiber products.
EXAMPLE:
250 lbs/hr (113.4 kg/hr) of diluted bitumen at 22.4 API (918.8 kg/m3) (stream
5 in
Figure 1 or 2) were processed at a 15 barrel/day (2.4 m3/day) dilbit feed
pilot plant.
The diluent was removed from the bitumen and 170.6 lbs/hr (77.4 kg/hr) of
bitumen
(stream 25 in Figure 1 or 2) was fed to the thermal reactor. The bitumen has
an API
of 7.7 API (1015.5 kg/m3). 141.6 lbs/hr (64.4 kg/hr) of pipelineable crude
(stream
200 in Figure 1 or 2) was produced at 19.1 API (938.5 kg/m3), 270 cSt, less
than
0.5w1% olefins, and less than 0.5wt% sediment and water. The processed crude
product meets pipeline specification. Of note, the processed crude measured a
micro-carbon residue (MGR) of less than 6wt%. 21.3 bls/hr (9.66 kg/hr) of 10-
15um
diameter general purpose carbon fiber (stream 120 in Figure 1 or 2) was
created
with a young Modulus of over 28 GPa and ultimate strength of over 170 MPa.
Approximately 4.3 lbs/hr (1.95 kg/hr) of solid material (stream 64 in Figure
2) was
created that can be used in the solid fuels market, and 3.4 lbs/hr (1.54
kg/hr) of fuel
gas (stream 43 in Figure 1 or 2) was generated for reusing in the process.
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DEFINITIONS:
Carbon fiber - Fiber containing at least 92 wt % carbon, while the fiber
containing at
least 99 wt % carbon is usually called a graphite fiber.
General purpose carbon fiber - Carbon fibers that have relatively low tensile
strength (less than 1 GPa) and low modulus (less than 100 GPa) respectively.
Isotropic-pitch-based carbon fibers belong to this grade and are used in
applications
that benefit from their low weight and bulkiness, e.g. thermal insulation for
a high-
temperature furnace, cement reinforcement and activated carbon fiber
applications).
Graphene - Graphene is an atomic-scale hexagonal lattice made of a single
layer of
carbon atoms. It is the basic structural element of many other allotropes of
carbon,
such as graphite, diamond, charcoal, carbon nanotubes and fullerenes.
Insolubles ¨ Material that precipitates into or remains in the solid form when
mixed
with a solvent.
Mesophase- A phase of matter intermediate between a liquid and solid, referred
to
zo as liquid crystals.
Non-Newtonian fluid ¨ A fluid that its viscosity (the gradual deformation by
shear or
tensile stresses) is dependent on shear rate or shear rate history. A Non-
Newtonian
fluid's viscosity can change when under force to either more liquid or more
solid.
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Pipelineable crude ¨ Heavy hydrocarbon with API less than or equal to 19
(density
>920 kg/m3), and/or more than 300 cst that requires some processing to meet
pipeline specifications of greater than API 19 (density <920 kg/m3), viscosity
less
than 300 cSt at reference temperature, sediment and water less than 0.4 wt%
and
olefins less than 1 wt% or non-detectable by the measurement tool used by the
transporter.
Transport hydrocarbon ¨ Diluent, condensate, hydrocarbon with Boiling range of
butane to 550 F nominally
Tensile strength ¨ Measure of the amount of force with which a fiber can be
pulled
before it breaks.
Young's modulus - Measure of a material's stiffness defined as the axial
stress
divided by the axial strain. The higher the modulus, the stiffer the material
(i.e. the
is greater the stress necessary to cause deformation).
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