U.S. patent application number 13/733713 was filed with the patent office on 2013-07-11 for process for making a distillate product and/or c2-c4 olefins.
This patent application is currently assigned to SHELL OIL COMPANY. The applicant listed for this patent is Shell Oil Company. Invention is credited to Ye-Mon CHEN, John William HARRIS, Martin Jean Pierre Cornelis NIESKENS, Easwar Santhosh RANGANATHAN, Colin John SCHAVERIEN.
Application Number | 20130178672 13/733713 |
Document ID | / |
Family ID | 47559464 |
Filed Date | 2013-07-11 |
United States Patent
Application |
20130178672 |
Kind Code |
A1 |
CHEN; Ye-Mon ; et
al. |
July 11, 2013 |
PROCESS FOR MAKING A DISTILLATE PRODUCT AND/OR C2-C4 OLEFINS
Abstract
A process for making a distillate product and one or more C2-C4
olefins from a FCC feedstock containing a cellulosic material and a
hydrocarbon co-feed is provided.
Inventors: |
CHEN; Ye-Mon; (Sugar Land,
TX) ; HARRIS; John William; (Amsterdam, NL) ;
NIESKENS; Martin Jean Pierre Cornelis; (Amsterdam, NL)
; RANGANATHAN; Easwar Santhosh; (Houston, TX) ;
SCHAVERIEN; Colin John; (Amsterdam, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Shell Oil Company; |
Houston |
TX |
US |
|
|
Assignee: |
SHELL OIL COMPANY
Houston
TX
|
Family ID: |
47559464 |
Appl. No.: |
13/733713 |
Filed: |
January 3, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61583678 |
Jan 6, 2012 |
|
|
|
Current U.S.
Class: |
585/240 ;
585/324 |
Current CPC
Class: |
C10G 1/08 20130101; C10G
3/62 20130101; C10G 11/18 20130101; C10G 11/182 20130101; C10G
1/002 20130101; C10G 3/57 20130101; C10G 2300/1014 20130101; C10G
51/026 20130101; C10G 2400/20 20130101; Y02P 30/20 20151101; C10G
3/49 20130101 |
Class at
Publication: |
585/240 ;
585/324 |
International
Class: |
C10G 1/00 20060101
C10G001/00 |
Claims
1. A process for making a distillate product and one or more C2-C4
olefins comprising: a) contacting a FCC feedstock with a FCC
catalyst at a temperature of at least 400.degree. C. in a riser
reactor to produce a distillate product and a spent FCC catalyst,
wherein the FCC feedstock comprises a cellulosic material and a
hydrocarbon co-feed; b) separating at least a portion of the
distillate product from the spent FCC catalyst; c) regenerating the
spent FCC catalyst to produce a regenerated FCC catalyst; d)
contacting an intermediate reactor feedstock with at least a
portion of the regenerated FCC catalyst at a temperature of at
least 500.degree. C. in an intermediate reactor to produce one or
more C2-C4 olefins and a used regenerated FCC catalyst; e)
separating at least a portion of the one or more C2-C4 olefins from
the used regenerated catalyst; and f) providing at least a portion
of the used regenerated FCC catalyst as FCC catalyst in step
a).
2. The process of claim 1 wherein the FCC feedstock comprises a
hydrocarbon co-feed and at least one cellulosic material selected
from the group consisting of a solid cellulosic material, a
pyrolysis oil derived from cellulosic material, and a mixture
thereof.
3. The process of claim 1 wherein the hydrocarbon co-feed comprises
at least 8 wt % elemental hydrogen, based on the total weight of
the hydrocarbon co-feed on a dry basis.
4. The process of claim 1 wherein the hydrocarbon co-feed comprises
in the range from at least 20 wt % to at most 100 wt % of at least
one paraffin, based on the total weight of the hydrocarbon
co-feed.
5. The process of claim 1 wherein the combination of the cellulosic
material and the hydrocarbon co-feed has an overall molar ratio of
hydrogen to carbon (H/C) of equal to or more than 1.1 (1.1/1).
6. The process of claim 1 wherein the cellulosic material is a
solid cellulosic material and said solid cellulosic material is
supplied to the riser reactor at a location upstream of the
location where the hydrocarbon co-feed is supplied to the riser
reactor.
7. The process of claim 1 wherein the FCC catalyst comprises
zeolite Y or ultrastable zeolite Y (USY) in combination with an MFI
type zeolite.
8. The process of claim 1 wherein step a) comprises contacting a
FCC feedstock with a FCC catalyst at a temperature of at least
400.degree. C. in a riser reactor to produce a
gasoline-containing-product, a distillate product and a spent FCC
catalyst; and wherein at least a portion of the
gasoline-containing-product is provided as an intermediate reactor
feedstock in step d).
9. The process of claim 1 wherein the intermediate reactor
feedstock in step d) comprises in the range from at least 20 wt %
to at most 65 wt % of one or more olefins, based on the total
weight of intermediate reactor feedstock.
10. The process of claim 9 wherein the one or more olefins are one
or more C5.sup.+-olefins.
11. The process of claim 1 wherein the intermediate reactor
feedstock in step d) comprises one or more hydrocarbon compounds,
and at least 80 wt % of said one or more hydrocarbon compounds has
a boiling temperature at 0.1 MPa in the range from at least
30.degree. C. to less than 221.degree. C.
12. The process of claim 1 wherein the temperature in step a) is
higher than the temperature in step d).
13. The process of claim 1 wherein the intermediate reactor
feedstock comprise further biological feed components.
14. A process for the preparation of a biofuel and/or a
biochemical, comprising a) contacting a FCC feedstock with a FCC
catalyst at a temperature of at least 400.degree. C. in a riser
reactor to produce a distillate product and a spent FCC catalyst,
wherein the FCC feedstock comprises a cellulosic material and a
hydrocarbon co-feed; b) separating at least a portion of the
distillate product from the spent FCC catalyst; c) regenerating the
spent FCC catalyst to produce a regenerated FCC catalyst; d)
contacting an intermediate reactor feedstock with at least a
portion of the regenerated FCC catalyst at a temperature of at
least 500.degree. C. in an intermediate reactor to produce one or
more C2-C4 olefins and a used regenerated FCC catalyst; e)
separating at least a portion of the one or more C2-C4 olefins from
the used regenerated catalyst; f) providing at least a portion of
the used regenerated FCC catalyst as FCC catalyst in step a); and
g) blending at least a portion of the distillate product and/or at
least a portion of the one or more C2-C4 olefins with one or more
other components to produce a biofuel and/or a biochemical.
15. The process of claim 14 wherein the FCC feedstock comprises a
hydrocarbon co-feed and at least one cellulosic material selected
from the group consisting of a solid cellulosic material, a
pyrolysis oil derived from cellulosic material, and a mixture
thereof.
16. The process of claim 14 wherein the temperature in step a) is
higher than the temperature in step d).
17. A process for the preparation of a biofuel and/or a
biochemical, comprising a) contacting a FCC feedstock with a FCC
catalyst at a temperature of at least 400.degree. C. in a riser
reactor to produce a distillate product and a spent FCC catalyst,
wherein the FCC feedstock comprises a cellulosic material and a
hydrocarbon co-feed; b) separating at least a portion of the
distillate product from the spent FCC catalyst; c) regenerating the
spent FCC catalyst to produce a regenerated FCC catalyst; d)
contacting an intermediate reactor feedstock with at least a
portion of the regenerated FCC catalyst at a temperature of at
least 500.degree. C. in an intermediate reactor to produce a used
regenerated FCC catalyst, one or more C2-C4 olefins and a
gasoline-containing-product, said gasoline-containing-product
comprises one or more hydrocarbon compounds, wherein at least 80 wt
% of such one or more hydrocarbon compounds has a boiling
temperature at 0.1 MPa in the range from equal to or more than
30.degree. C. to less than 221.degree. C.; e) separating at least a
portion of the gasoline-containing-product and at least a portion
of the one or more C2-C4 olefins from the used regenerated
catalyst; f) providing at least a portion of the used regenerated
FCC catalyst as FCC catalyst in step a); and g) blending at least a
portion of the distillate product and/or at least a portion of the
gasoline-containing-product with one or more other components to
produce a biofuel and/or a biochemical.
18. The process of claim 17 wherein the FCC feedstock comprises a
hydrocarbon co-feed and at least one cellulosic material selected
from the group consisting of a solid cellulosic material, a
pyrolysis oil derived from cellulosic material, and a mixture
thereof.
19. The process of claim 17 wherein the temperature in step a) is
higher than the temperature in step d).
Description
[0001] The present application claims the benefit of U.S.
Provisional Patent Application Ser. No. 61/583,678, filed Jan. 6,
2012, the entire disclosure of which is hereby incorporated by
reference.
FIELD OF THE INVENTION
[0002] The invention relates to a process for making a distillate
product and/or C2-C4 olefins.
BACKGROUND OF THE INVENTION
[0003] The fluidized catalytic cracking (FCC) of heavy hydrocarbons
to produce lower boiling hydrocarbon products such as gasoline is
well known in the art. FCC processes have been around since the
1940's. Typically, a FCC unit or process includes at least a riser
reactor, a catalyst separator and a regenerator. A feedstock is
introduced into the riser reactor wherein it is contacted with hot
FCC catalyst from the regenerator. The mixture of the feedstock and
FCC catalyst passes through the riser reactor and into the catalyst
separator wherein the hydrocarbon product is separated from the FCC
catalyst. The separated hydrocarbon product passes from the
catalyst separator to a downstream system for further separation
and the separated catalyst passes to the regenerator where the coke
deposited on the FCC catalyst during the cracking reaction is
burned off the catalyst to provide a regenerated catalyst. The
resulting regenerated catalyst is used as the aforementioned hot
FCC catalyst and is mixed with the FCC feedstock that is introduced
into the riser reactor.
[0004] Many FCC processes and systems are designed so as to provide
for a high conversion of the FCC feedstock to products having
boiling temperatures in the gasoline boiling range. There are
situations, however, when it is desirable to provide for the high
conversion of the FCC feedstock to lower olefins, such as C2-C4
olefins, and/or to a distillate product, which distillate product
may comprise products having boiling temperatures in the diesel
boiling range--as opposed to products having boiling temperatures
in the gasoline boiling range.
[0005] US2006/0231461 describes a process for making middle
distillate and lower olefins. In this process a dense phase
reactor, or fixed fluidized bed reactor is used between the
catalyst regenerator and the riser reactor of a FCC process or unit
to provide for an improved middle distillate yield and for enhanced
selectivity towards the production of lower olefins. The dense
phase reactor is used to provide for the cracking of a gasoline
feedstock to yield lower olefins and for the conditioning of the
catalyst so that this catalyst is more suitable for the production
of a middle distillate product in the riser reactor.
[0006] It would be desirable to produce such middle distillate
product and such lower olefins in a sustainable manner.
[0007] Without wishing to be bound by any kind of theory, some may
consider that carbon is present in the atmosphere as CO.sub.2 and
that photoautotrophs like plants, algae and some bacteria fix this
inorganic carbon to organic carbon (such as for example
carbohydrates) using sunlight for energy. Over geological time
frames (>10.sup.6 years) organic matter (plant materials) is
fossilized to provide petroleum, natural gas and coal. It is stated
that when consuming these fossil resources to make polymers,
chemicals & fuel the carbon is released back into the
atmosphere as CO.sub.2 in a short time frame of 1-10 years. In this
case, it is argued that the rate at which biomass is converted to
fossil resources is in total imbalance with the rate at which
fossil resources are consumed and liberated. However, when using
annually renewable crops or biomass as the feedstocks for
manufacturing our carbon based polymers, chemicals and fuels, the
rate at which CO.sub.2 is fixed equals the rate at which it is
consumed and liberated. Using annually renewable carbon feedstocks
allows for sustainable development of carbon based materials and
for control and even reduction of CO.sub.2 emissions to help meet
global CO.sub.2 emissions standards under the Kyoto protocol.
[0008] It would be an advancement in the art to provide processes
that may help to create sustainable CO.sub.2 emissions or even
reduce CO.sub.2 emissions from a refinery and/or to provide
processes that can be beneficial in a CO.sub.2 capture and trade
scheme.
[0009] WO2008/127956 describes a system comprising a riser reactor
comprising a gas oil feedstock and a first catalyst under catalytic
cracking conditions to yield a riser reactor product comprising a
cracked gas oil product and a first used catalyst; an intermediate
reactor comprising at least a portion of the cracked gas oil
product and a second catalyst under high severity conditions to
yield a cracked intermediate reactor product and a second used
catalyst; wherein the intermediate reactor feedstock comprises at
least one of a fatty acid and a fatty acid ester. This fatty acid
and/or fatty acid ester can for example be obtained plant oils,
such as for example palm oil, coconut oil, corn oil, soya oil,
safflower oil, sunflower oil, linseed oil, olive oil and peanut oil
and/or animal fats.
[0010] A disadvantage of the process as described in WO2008/127956,
however, is that the use of plant oils and/or animal fats as an FCC
feedstock may compete with their use as food.
SUMMARY OF THE INVENTION
[0011] It has now been found that such an FCC process can be
obtained by feeding a cellulosic material, such as for example
pyrolysis oil and/or wood, in the right location into the FCC
process.
[0012] Accordingly, in an embodiment, a process for making a
distillate product and one or more C2-C4 olefins is provided
comprising:
a) contacting a FCC feedstock with a FCC catalyst at a temperature
of at least 400.degree. C. in a riser reactor to produce a
distillate product and a spent FCC catalyst, wherein the FCC
feedstock comprises a cellulosic material and a hydrocarbon
co-feed; b) separating at least a portion of the distillate product
from the spent FCC catalyst; c) regenerating the spent FCC catalyst
to produce a regenerated FCC catalyst; d) contacting an
intermediate reactor feedstock with at least a portion of the
regenerated FCC catalyst at a temperature of at least 500.degree.
C. in an intermediate reactor to produce one or more C2-C4 olefins
and a used regenerated FCC catalyst; e) separating at least a
portion of the one or more C2-C4 olefins from the used regenerated
catalyst; and f) providing at least a portion of the used
regenerated FCC catalyst as FCC catalyst in step a).
[0013] In another embodiment, a process for the preparation of a
biofuel and/or a biochemical is provided comprising
a) contacting a FCC feedstock with a FCC catalyst at a temperature
of at least 400.degree. C. in a riser reactor to produce a
distillate product and a spent FCC catalyst, wherein the FCC
feedstock comprises a cellulosic material and a hydrocarbon
co-feed; b) separating at least a portion of the distillate product
from the spent FCC catalyst; c) regenerating the spent FCC catalyst
to produce a regenerated FCC catalyst; d) contacting an
intermediate reactor feedstock with at least a portion of the
regenerated FCC catalyst at a temperature of at least 500.degree.
C. in an intermediate reactor to produce one or more C2-C4 olefins
and a used regenerated FCC catalyst; e) separating at least a
portion of the one or more C2-C4 olefins from the used regenerated
catalyst; f) providing at least a portion of the used regenerated
FCC catalyst as FCC catalyst in step a); and g) blending at least a
portion of the distillate product and/or at least a portion of the
one or more C2-C4 olefins with one or more other components to
produce a biofuel and/or a biochemical.
[0014] In yet another embodiment, a process for the preparation of
a biofuel and/or a biochemical is provided comprising
a) contacting a FCC feedstock with a FCC catalyst at a temperature
of at least 400.degree. C. in a riser reactor to produce a
distillate product and a spent FCC catalyst, wherein the FCC
feedstock comprises a cellulosic material and a hydrocarbon
co-feed; b) separating at least a portion of the distillate product
from the spent FCC catalyst; c) regenerating the spent FCC catalyst
to produce a regenerated FCC catalyst; d) contacting an
intermediate reactor feedstock with at least a portion of the
regenerated FCC catalyst at a temperature of at least 500.degree.
C. in an intermediate reactor to produce a used regenerated FCC
catalyst, one or more C2-C4 olefins and a
gasoline-containing-product, said gasoline-containing-product
comprises one or more hydrocarbon compounds, wherein at least 80 wt
% of such one or more hydrocarbon compounds has a boiling
temperature at 0.1 MPa in the range from equal to or more than
30.degree. C. to less than 221.degree. C.; e) separating at least a
portion of the gasoline-containing-product and at least a portion
of the one or more C2-C4 olefins from the used regenerated
catalyst; f) providing at least a portion of the used regenerated
FCC catalyst as FCC catalyst in step a); and g) blending at least a
portion of the distillate product and/or at least a portion of the
gasoline-containing-product with one or more other components to
produce a biofuel and/or a biochemical.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a process flow schematic representing an
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] It would be more preferred to use non-edible renewable
energy sources, such as some cellulosic materials such as wood, as
an FCC feedstock.
[0017] It would therefore be an advancement in the art to provide
an FCC process for the production of a distillate and C2-C4
olefins, that allows one to use a non-edible renewable energy
source, such as a cellulosic material, as a feedstock.
[0018] Accordingly, in an embodiment provides a process for making
a distillate product and one or more C2-C4 olefins comprising:
a) contacting a FCC feedstock with a FCC catalyst at a temperature
of equal to or more than 400.degree. C. in a riser reactor to
produce a distillate product and a spent FCC catalyst, wherein the
FCC feedstock comprises a cellulosic material and a hydrocarbon
co-feed; b) separating at least part of the distillate product from
the spent FCC catalyst; c) regenerating the spent FCC catalyst to
produce a regenerated FCC catalyst; d) contacting an intermediate
reactor feedstock with at least part of the regenerated FCC
catalyst at a temperature of equal to or more than 500.degree. C.
in an intermediate reactor to produce one or more C2-C4 olefins and
a used regenerated FCC catalyst; e) separating at least part of the
one or more C2-C4 olefins from the used regenerated catalyst; f)
using at least part of the used regenerated FCC catalyst as FCC
catalyst in step a).
[0019] Without wishing to be bound by any kind of theory, it is
believed that when cellulosic materials (such as solid cellulosic
material and/or pyrolysis oil) are catalytically cracked, much more
coke is formed than when vegetable oils and/or animal fat are
catalytically cracked. Therefore, if cellulosic materials, such as
solid cellulosic material and/or pyrolysis oil, were fed to the
intermediate reactor--similar to the fatty acids and/or fatty acid
esters in WO2008/127956--excessive coke would form on the catalyst
and the used catalyst could no longer be used for the production of
any distillate product in the riser reactor.
[0020] However, it was found that the cellulosic material(s) can be
used as a feedstock in the process for the making of a distillate
product and one or more C2-C4 olefins, when the cellulosic
material(s) is fed into the riser reactor instead of the
intermediate reactor and when the cellulosic material(s) are fed
together with a hydrocarbon co-feed.
[0021] Operating an FCC process in a mode for the production of a
distillate product and one or more C2-C4 olefins--rather than a
mode for the production of a gasoline product--further has the
advantage that a lower temperature can be used in the riser
reactor, thereby further reducing coke formation due to the
cellulosic material feed. Operating at such lower temperature may
result in lower yields of C3 and/or C4 hydrocarbon products, such
as for example propane, propene, butanes and/or butenes. In
addition, operating at such lower temperature may result in a more
olefinic gasoline that may be more difficult to blend with other
components in a fuel. Conveniently, however, the process according
to the invention allows one to optionally recycle any olefinic
gasoline, made as a product in the riser reactor, as a feed to the
intermediate reactor in step d) of the process. In this
intermediate reactor such olefinic gasoline can advantageously be
converted into C3 and/or C4 hydrocarbon products and a blendable
gasoline.
[0022] Hence, the process of the present invention advantageously
allows one to use a non-edible renewable energy source, such as a
cellulosic material, as a feedstock in an FCC process for the
making of a distillate product and one or more C2-C4 olefins.
[0023] In step a) of the process according to the invention a FCC
feedstock is contacted with a FCC catalyst at a temperature of
equal to or more than 400.degree. C. in a riser reactor to produce
a distillate product and a spent FCC catalyst.
[0024] The Fluidized Catalytic Cracking (FCC) feedstock can
comprise one or more cellulosic material(s). Preferably the FCC
feedstock comprises a solid cellulosic material, a pyrolysis oil
derived from cellulosic material, and/or a mixture thereof. In an
especially preferred embodiment the FCC feedstock comprises one or
more material(s) chosen from the group of non-edible solid
cellulosic material, pyrolysis oil and/or mixtures thereof. By a
non-edible material is herein understood a material that is not
suitable for human consumption.
[0025] By a cellulosic material is herein understood and defined as
a material comprising cellulose, hemicellulose, lignocellulose
and/or lignin; a material derived therefrom; and/or mixtures of
such materials. For example, pyrolysis oil may be considered a
liquid material derived from a cellulosic material. More preferably
the cellulosic material comprises lignocellulose or a material
derived thereof. Such a material that comprises lignocellulose is
also referred to as a lignocellulosic material. Preferably, the
cellulosic material is a solid cellulosic material or a liquid or
gaseous material derived of such a solid cellulosic material. Most
preferably the cellulosic material is a solid cellulosic material,
a pyrolysis oil derived (produced) from cellulosic material, and/or
a mixture thereof.
[0026] Preferably the cellulosic material is not a material used
for human food production. Examples of suitable cellulosic
materials include aquatic plants and algae, agricultural waste
and/or forestry waste and/or paper waste and/or plant material
obtained from domestic waste and/or sugar processing residues
and/or mixtures thereof. Examples of suitable cellulosic materials
include agricultural wastes such as corn stover, soybean stover,
corn cobs, rice straw, rice hulls, oat hulls, corn fibre, cereal
straws such as wheat straw, barley straw, rye straw and oat straw;
grasses; forestry products and/or forestry residues such as wood
and wood-related materials such as wood chips, sawdust, bark or the
needles of trees; waste paper; sugar processing residues such as
bagasse and beet pulp; or mixtures thereof.
[0027] More preferably the cellulosic material is a solid
cellulosic material selected from the group consisting of wood,
sawdust, straw, grass, bagasse, corn stover and/or mixtures
thereof. These solid cellulosic materials are advantageous as they
do not compete with human food production and are therefore
considered more sustainable.
[0028] The cellulosic material may also be a material derived from
the above materials, for example liquid and gaseous materials
derived from the above cellulosic material by pyrolysis,
(hydro)-liquefaction (also sometimes referred to as solvolysis),
torrefaction or other treatments. More preferably the cellulosic
material is a, optionally torrefied, solid cellulosic material or a
pyrolysis oil.
[0029] By a pyrolysis oil is herein understood an oil obtained by
pyrolysis of a cellulosic material. The pyrolysis oil may be
upgraded by hydrotreatment and/or hydrodeoxygenation (for example
to substantially reduce the oxygen content of the pyrolysis oil).
Preferably, however, an essentially untreated pyrolysis oil is used
which has not or essentially not been upgraded by hydrotreatment
and/or hydrodeoxygenation, as such hydrotreatment and/or
hydrodeoxygenation can advantageously be avoided in the processes
according to the invention. The pyrolysis oil may comprise a
"whole" pyrolysis oil or a part thereof.
[0030] By pyrolysis is herein understood the thermal decomposition
of a, preferably solid, cellulosic material at a temperature of
equal to or more than 350.degree. C. The concentration of oxygen is
preferably less than the concentration required for complete
combustion. More preferably the pyrolysis is carried out in the
essential absence of non-in-situ-generated oxygen. A limited amount
of oxygen may be generated in-situ during the pyrolysis process.
Preferably pyrolysis is carried out in an oxygen-poor, preferably
an oxygen-free, atmosphere. More preferably pyrolysis is carried
out in an atmosphere containing equal to or less than 5 vol. %
oxygen, more preferably equal to or less than 1 vol. % oxygen and
most preferably equal to or less than 0.1 vol. % oxygen. In a most
preferred embodiment pyrolysis is carried out in the essential
absence of oxygen.
[0031] The pyrolysis temperature is preferably equal to or more
than 350.degree. C., more preferably equal to or more than
400.degree. C. and most preferably equal to or more than
450.degree. C. The pyrolysis temperature is further preferably
equal to or less than 800.degree. C., more preferably equal to or
less than 700.degree. C. and most preferably equal to or less than
650.degree. C.
[0032] The pyrolysis pressure may vary widely. For practical
purposes a pressure in the range from 0.01 to 0.5 MPa (MegaPascal),
more preferably in the range from 0.1 to 0.2 MPa is preferred. Most
preferred is an atmospheric pressure (about 0.1 MPa).
[0033] By torrefying or torrefaction is herein understood the
treatment of the solid cellulosic material at a temperature in the
range from equal to or more than 200.degree. C. to equal to or less
than 350.degree. C. in the essential absence of a catalyst and in
an oxygen-poor, preferably an oxygen-free, atmosphere. By an
oxygen-poor atmosphere is understood an atmosphere containing equal
to or less than 15 vol. % oxygen, preferably equal to or less than
10 vol. % oxygen and more preferably equal to or less than 5 vol. %
oxygen. By an oxygen-free atmosphere is understood an atmosphere
where oxygen is essentially absent.
[0034] Torrefying of a solid cellulosic material is preferably
carried out at a temperature of more than 200.degree. C., more
preferably at a temperature equal to or more than 210.degree. C.,
still more preferably at a temperature equal to or more than
220.degree. C., yet more preferably at a temperature equal to or
more than 230.degree. C. In addition torrefying of a solid
cellulosic material is preferably carried out at a temperature less
than 350.degree. C., more preferably at a temperature equal to or
less than 330.degree. C., still more preferably at a temperature
equal to or less than 310.degree. C., yet more preferably at a
temperature equal to or less than 300.degree. C.
[0035] Torrefaction of any solid cellulosic material is preferably
carried out in the essential absence of oxygen. More preferably the
torrefaction is carried under an inert atmosphere, containing for
example inert gases such as nitrogen, carbon dioxide and/or steam;
and/or under a reducing atmosphere in the presence of a reducing
gas such as hydrogen, gaseous hydrocarbons such as methane and
ethane or carbon monoxide.
[0036] Any torrefaction may be carried out at a wide range of
pressures. Preferably, however, the torrefaction is carried out at
atmospheric pressure (about 0.1 MPa). In addition, the torrefaction
may be carried out batchwise or continuously.
[0037] The torrefied solid cellulosic material has a higher energy
density, a higher mass density and greater flowability, making it
easier to transport, pelletize and/or store. Being more brittle, it
can be easier reduced into smaller particles.
[0038] If the cellulosic material comprises a solid cellulosic
material, the process according to the invention preferably
comprises an additional step wherein the particle size of such
solid cellulosic material is reduced before using it as part of the
FCC feedstock in step a).
[0039] Preferably any solid cellulosic material used as part of the
FCC feedstock in step a) is a micronized solid cellulosic material.
By a micronized solid cellulosic material is herein understood a
solid cellulosic material that has a particle size distribution
with a mean particle size in the range from equal to or more than 5
micrometer to equal to or less than 5000 micrometer, as measured
with a laser scattering particle size distribution analyzer.
[0040] The particle size of any solid cellulosic material, can
optionally be reduced before or after such solid cellulosic
material is torrefied. Such a particle size reduction may for
example be especially advantageous when such solid cellulosic
material comprises wood or torrefied wood. The particle size of
any, optionally torrefied, solid cellulosic material can be reduced
in any manner known to the skilled person to be suitable for this
purpose. Suitable methods for particle size reduction include
crushing, grinding and/or milling. The particle size reduction may
for example be achieved by means of a ball mill, hammer mill,
(knife) shredder, chipper, knife grid, or cutter.
[0041] Preferably any solid cellulosic material used in the FCC
feedstock in step a) has a particle size distribution where the
mean particle size lies in the range from equal to or more than 5
micrometer (micron), more preferably equal to or more than 10
micrometer, even more preferably equal to or more than 20
micrometer, and most preferably equal to or more than 100
micrometer to equal to or less than 5000 micrometer, more
preferably equal to or less than 1000 micrometer and most
preferably equal to or less than 500 micrometer.
[0042] For practical purposes the particle size distribution and
mean particle size of the solid cellulosic material can be
determined with a Laser Scattering Particle Size Distribution
Analyzer, preferably a Horiba LA950, according to the ISO 13320
method titled "Particle size analysis--Laser diffraction
methods".
[0043] In addition to the cellulosic material, the FCC feedstock
also comprises a hydrocarbon co-feed (herein also referred to as
hydrocarbon feed). The hydrocarbon co-feed comprises one or more
material(s) other than the cellulosic material described above. The
hydrocarbon co-feed hence comprises one or more material(s) other
than for example a solid cellulosic material; a pyrolysis oil; or a
mixture thereof.
[0044] By a hydrocarbon feed is herein understood a feed that
contains one or more hydrocarbon compounds. By a hydrocarbon
compound is herein understood a compound that contains both
hydrogen and carbon and preferably consists of hydrogen and carbon.
Preferably the hydrocarbon co-feed is a fluid hydrocarbon co-feed.
By a fluid hydrocarbon co-feed is herein understood a hydrocarbon
co-feed that is not in a solid state when contacted with the FCC
catalyst. The hydrocarbon co-feed is preferably fed via a feed
nozzle into the riser reactor in an essentially liquid state, in an
essentially gaseous state or in a partially liquid-partially
gaseous state. For hydrocarbon co-feeds that are highly viscous, it
may therefore be advantageous to preheat such feeds before entering
the feed nozzle. The hydrocarbon co-feed is preferably in a gaseous
state when contacted with the catalytic cracking catalyst. When
entering the riser reactor in an essentially or partially liquid
state, the fluid hydrocarbon co-feed preferably vaporizes upon
entry and preferably is contacted in a gaseous state with the FCC
catalyst and/or the cellulosic material.
[0045] The hydrocarbon co-feed can for example be any non-solid
hydrocarbon co-feed known to the skilled person to be suitable as a
feed for a catalytic cracking unit. The hydrocarbon co-feed can for
example be obtained from a conventional crude oil (also sometimes
referred to as a petroleum oil or mineral oil), an unconventional
crude oil (that is, oil produced or extracted using techniques
other than the traditional oil well method) or a Fischer Tropsch
oil (sometimes referred to as a synthetic oil) and/or a mixture
thereof.
[0046] The hydrocarbon co-feed may also be a hydrocarbon co-feed
from a renewable source, such as for example a vegetable oil.
[0047] In one embodiment the hydrocarbon co-feed is derived from a,
preferably conventional, crude oil. Examples of conventional crude
oils include West Texas Intermediate crude oil, Brent crude oil,
Dubai-Oman crude oil, Arabian Light crude oil, Midway Sunset crude
oil or Tapis crude oil. Such oils are sometimes also referred to as
mineral oils and preferably the hydrocarbon co-feed is therefore a
mineral hydrocarbon co-feed. By a mineral hydrocarbon co-feed is
understood a hydrocarbon co-feed that comprises or is derived from
a mineral oil.
[0048] More preferably the hydrocarbon co-feed comprises a fraction
of a, preferably conventional, crude oil or renewable oil.
Preferred hydrocarbon co-feeds include straight run (atmospheric)
gas oils, flashed distillate, vacuum gas oils (VGO), coker gas
oils, diesel, gasoline, kerosene, naphtha, liquefied petroleum
gases, atmospheric residue ("long residue") and vacuum residue
("short residue") and/or mixtures thereof. Most preferably the
hydrocarbon co-feed comprises a long residue and/or VGO.
[0049] The composition of the hydrocarbon co-feed may vary widely.
The hydrocarbon co-feed may for example contain paraffins, olefins
and aromatics. By paraffins both normal-, cyclo- and
branched-paraffins are understood.
[0050] In a preferred embodiment the hydrocarbon co-feed comprises
one or more paraffins, for example in the range from equal to or
more than 20 wt % to equal to or less than 100 wt % of one or more
paraffins, preferably in the range from equal to or more than 50 wt
% of one or more paraffins, more preferably from equal to or more
than 70 wt % of one or more paraffins, most preferably from equal
to or more than 90 wt %, to equal to or less than 100 wt % of one
or more paraffins, based on the total weight of the hydrocarbon
co-feed. Such a hydrocarbon co-feed comprising one or more
paraffins is herein also referred to as a paraffinic hydrocarbon
co-feed.
[0051] For practical purposes the paraffin content of all
hydrocarbon co-feeds having an initial boiling point of at least
260.degree. C. can be measured by means of ASTM method D2007-03
titled "Standard test method for characteristic groups in rubber
extender and processing oils and other petroleum-derived oils by
clay-gel absorption chromatographic method", wherein the amount of
saturates will be representative for the paraffin content. For all
other hydrocarbon co-feeds the paraffin content of the hydrocarbon
co-feed can be measured by means of comprehensive multi-dimensional
gas chromatography (GC.times.GC), as described in P. J.
Schoenmakers, J. L. M. M. Oomen, J. Blomberg, W. Genuit, G. van
Velzen, J. Chromatogr. A, 892 (2000) p. 29 and further.
[0052] Examples of paraffinic hydrocarbon co-feeds include
so-called Fischer-Tropsch derived hydrocarbon streams such as
described in WO2007/090884 and herein incorporated by reference, or
a hydrotreater product or hydrowax. By hydrowax is understood the
bottoms fraction of a hydrocracker. Examples of hydrocracking
processes which may yield a bottoms fraction that can be used as
hydrocarbon co-feed, are described in EP-A-699225, EP-A-649896,
WO-A-97/18278, EP-A-705321, EP-A-994173 and U.S. Pat. No. 4,851,109
and herein incorporated by reference.
[0053] In a preferred embodiment the hydrocarbon co-feed comprises
equal to or more than 11 wt % elemental hydrogen, more preferably
equal to or more than 12 wt % elemental hydrogen (i.e. hydrogen
atoms), based on the total weight of the hydrocarbon co-feed on a
dry basis (i.e. water-free basis). A high content of elemental
hydrogen, such as a content of equal to or more than 12.2 wt %,
allows the hydrocarbon co-feed to act as a cheap hydrogen donor in
the catalytic cracking process. A particularly preferred
hydrocarbon co-feed having an elemental hydrogen content of equal
to or more than 12.5 wt % is Fischer-Tropsch derived waxy
raffinate. Such Fischer-Tropsch derived waxy raffinate may for
example comprise about 85 wt % of elemental carbon and 15 wt % of
elemental hydrogen.
[0054] The weight ratio of the cellulosic material to hydrocarbon
co-feed may vary widely.
[0055] The weight ratio of hydrocarbon co-feed to cellulosic
material is preferably equal to or more than 50 to 50 (5:5), more
preferably equal to or more than 70 to 30 (7:3), still more
preferably equal to or more than 80 to 20 (8:2), even still more
preferably equal to or more than 90 to 10 (9:1). For practical
purposes the weight ratio of hydrocarbon co-feed to cellulosic
material is preferably equal to or less than 99.9 to 0.1
(99.9:0.1), more preferably equal to or less than 95 to 5 (95:5).
The hydrocarbon co-feed and the cellulosic material are preferably
being fed to the catalytic cracking reactor in a weight ratio
within the above ranges. If the cellulosic material is a solid
cellulosic material, the amount of solid cellulosic material, based
on the total weight of the FCC feedstock, is preferably equal to or
less than 30 wt %, more preferably equal to or less than 20 wt %,
most preferably equal to or less than 10 wt % and even more
preferably equal to or less than 5 wt %. For practical purposes the
amount of any solid cellulosic material present, based on the total
weight of the FCC feedstock, is preferably equal to or more than
0.1 wt %, more preferably equal to or more than 1 wt %.
[0056] When the cellulosic material comprises a pyrolysis oil, the
feed supplied to the catalytic cracking reactor may preferably
comprise in the range from equal to or more than 5 wt %, more
preferably from equal to or more than 10 wt % to equal to or less
than 99 wt %, more preferably equal to or less than 90 wt % of such
pyrolysis oil based on the total weight of the FCC feedstock.
[0057] Preferably the combination of the, preferably solid,
cellulosic material and the hydrocarbon co-feed has an overall
molar ratio of hydrogen to carbon (H/C) of equal to or more than
1.1 (1.1/1), more preferably of equal to or more than 1.2 (1.2/1),
most preferably of equal to or more than 1.3 (1.3/1). For practical
purposes the FCC feedstock may for example have an overall molar
ratio of hydrogen to carbon (H/C) in the range from equal to or
more than 1.1 (1.1/1) to equal to or less than 2.15 (2.15/1).
[0058] The hydrocarbon co-feed and the cellulosic material can be
mixed prior to entry into the riser reactor or they can be added
separately, at the same location or at different locations to the
riser reactor.
[0059] In one embodiment the hydrocarbon co-feed and the cellulosic
material are not mixed together prior to entry into the riser
reactor. In this embodiment the hydrocarbon co-feed and the
cellulosic material may be fed simultaneously (that is at one
location) to the riser reactor, and optionally mixed upon entry of
the riser reactor; or, alternatively, the hydrocarbon co-feed and
the cellulosic material may be added separately (at different
locations) to the riser reactor. Riser reactors can have multiple
feed inlet nozzles. The cellulosic material and the hydrocarbon
co-feed can therefore be processed in the riser reactor even if
both components are not miscible by feeding each component through
a separate feed inlet nozzle.
[0060] When the cellulosic material is a solid cellulosic material,
such solid cellulosic material is preferably supplied to the riser
reactor at a location upstream of the location where the
hydrocarbon co-feed is supplied to the riser reactor. Without
wishing to be bound by any kind of theory it is believed that this
allows the solid cellulosic material to be contacted with the FCC
catalyst first; allowing the solid cellulosic material to be
converted into an intermediate oil product and allowing this
intermediate oil product to be at least partly and preferably
wholly vaporized before the FCC catalyst is quenched by addition of
a hydrocarbon co-feed. Further supplying the solid cellulosic
material upstream of the hydrocarbon co-feed allows for longer
residence times for the solid cellulosic material (when compared to
the residence time for the hydrocarbon co-feed), making it possible
to use a solid cellulosic material with a particle size
distribution having a mean particle size of equal to or more than
2000 micrometer.
[0061] In another embodiment the hydrocarbon co-feed and the
cellulosic material are mixed together prior to entry into a riser
reactor to provide a feed mixture comprising the hydrocarbon
co-feed and the cellulosic material. The feed mixture may be
prepared just before entry to a riser reactor or it may optionally
be held in a stirred feed vessel before being forwarded to a riser
reactor.
[0062] The fluidized catalytic cracking (FCC) catalyst preferably
comprises a zeolite (also sometimes referred to as a crystalline
aluminosilicate), preferably dispersed in an amorphous matrix
component. For example the FCC catalyst may comprise amorphous
silica alumina and a zeolite. In addition, the FCC catalyst
preferably comprises a binder and/or a filler.
[0063] In a preferred embodiment the FCC catalyst includes a
so-called "large pore" zeolite. By a "large pore" zeolite is herein
understood a zeolite comprising a porous, crystalline
aluminosilicate structure having a porous internal cell structure
on which the major axis of the pores is in the range of 0.62
nanometer to 0.8 nanometer. The axes of zeolites are depicted in
the `Atlas of Zeolite Structure Types`, of W. M. Meier, D. H.
Olson, and Ch. Baerlocher, Fourth Revised Edition 1996, Elsevier,
ISBN 0-444-10015-6. Examples of such large pore zeolites include
FAU or faujasite.
[0064] In a preferred embodiment the FCC catalyst includes a
zeolite chosen from the group consisting of Y zeolites; ultrastable
Y zeolites (USY); X zeolites, zeolite beta, zeolite L, offretite,
mordenite, faujasite (including synthetic faujasite), and zeolite
omega, Rare Earth zeolite Y (=REY) and Rare Earth USY (REUSY).
[0065] If the FCC catalyst comprises a Y-type zeolite, such a
Y-type zeolite preferably comprises an overall silica-to-alumina
mole ratio of more than 3.0, more preferably an overall silica-to
alumina mole ratio of between about 3.0 and about 6.0.
[0066] The FCC catalyst can also comprise a so-called medium pore
zeolite" in addition to the above mentioned zeolites. By a "medium
pore" zeolite is herein understood a zeolite comprising a porous,
crystalline aluminosilicate structure having a porous internal cell
structure on which the major axis of the pores is in the range of
0.45 nanometer to 0.62 nanometer.
[0067] Hence, in addition to the above mentioned zeolites, the FCC
catalyst preferably includes a zeolite chosen from the group
consisting of MFI type zeolites (such as for example ZSM-5); MTW
type zeolites (such as for example ZSM-12); MTT type zeolites (such
as for example ZSM-23) the TON type zeolites (such as for example
zeolite theta one or ZSM-22); and the FER structural type, for
example, ferrierite. Of these MFI type zeolites, preferably ZSM-5,
are most preferred.
[0068] In a preferred embodiment the FCC catalyst comprises zeolite
Y or ultrastable zeolite Y (USY) in combination with an MFI type
zeolite such as ZSM-5.
[0069] If the FCC catalyst comprises both a large pore zeolite and
a medium pore zeolite, the ratio of the large pore zeolite to the
medium pore size zeolite in the FCC catalyst is preferably in the
range of 99:1 to 70:30, more preferably in the range of 98:2 to
85:15.
[0070] In a preferred embodiment the stability and/or acidity of a
zeolite used in the FCC catalyst can be increased by exchanging the
zeolite with hydrogen ions, ammonium ions, polyvalent metal
cations, such as rare earth-containing cations, magnesium cations
or calcium cations, or a combination of hydrogen ions, ammonium
ions and polyvalent metal cations, thereby lowering the sodium
content until it is less than about 0.8 weight percent, preferably
less than about 0.5 weight percent and or less than about 0.3
weight percent, calculated as Na.sub.2O.
[0071] The FCC catalyst further preferably comprises an amorphous
matrix component. Examples of such an amorphous matrix include
amorphous silica-alumina, amorphous silica, amorphous alumina,
amorphous titania, amorphous zirconia and amorphous magnesium
oxide, or combinations of two or more of these.
[0072] In addition the FCC catalyst may comprise binders and/or
fillers. An example of a binder is silica sol. Examples of fillers
include natural or synthetic clays, pillared or delaminated clays,
or mixtures of one or more of these. Examples of clays which may be
present in the FCC catalyst include kaolin, hectorite, sepiolite
and attapulgite.
[0073] The total amount of zeolite that is present in the FCC
catalyst is preferably in the range of 5 wt % to 50 wt %, more
preferably in the range of 10 wt % to 30 wt %, and even more
preferably in the range of 10 wt % to 25 wt % relative to the total
mass of the FCC catalyst, whilst the remainder is preferably
amorphous matrix component, binder and/or filler.
[0074] By a riser reactor is herein understood an elongated
essentially tube-shaped reactor. Such reactors are suitable for
carrying out catalytic cracking reactions. The elongated
essentially tube-shaped reactor is preferably oriented in an
essentially vertical manner.
[0075] Examples of suitable riser reactors are described in the
Handbook titled "Fluid Catalytic Cracking technology and
operations", by Joseph W. Wilson, published by PennWell Publishing
Company (1997), chapter 3, especially pages 101 to 112, herein
incorporated by reference.
[0076] The riser reactor may be a so-called internal riser reactor
or a so-called external riser reactor as described therein.
[0077] Most preferably the internal riser reactor is an essentially
vertical, essentially tube-shaped reactor, that may have an
essentially vertical upstream end located outside a vessel and an
essentially vertical downstream end located inside the vessel. The
vessel is suitably a reaction vessel suitable for catalytic
cracking reactions and/or a vessel that comprises one or more
cyclone separators and/or swirl tubes. The internal riser reactor
is especially advantageous when at least part of the feed comprises
a solid cellulosic material or a pyrolysis oil. The solid
cellulosic material may be converted in-situ into a pyrolysis oil.
Without wishing to be bound to any kind of theory it is believed
that an internal riser reactor may reduce polymerization of any
olefins formed, thereby reducing plugging risks and maintenance or
service requirements.
[0078] When an external riser reactor is used, it may be
advantageous to use an external riser reactor with a curve or low
velocity zone at its upper end as for example illustrated in the
Handbook titled "Fluid Catalytic Cracking technology and
operations", by Joseph W. Wilson, published by PennWell Publishing
Company (1997), chapter 3, FIG. 3-7, herein incorporated by
reference. It has been advantageously found that a part of the
catalytic cracking catalyst may deposit in the curve or low
velocity zone, thereby forming a protective layer against corrosion
by any residual solid cellulosic material particles and/or any
oxygen-containing hydrocarbons contained in a pyrolysis oil.
[0079] It may be advantageous to add a lift gas at the bottom of
the riser reactor. Examples of such a liftgas include steam,
vaporized oil and/or oil fractions, and/or any mixtures of these.
Steam is most preferred as a lift gas from a practical perspective.
However, the use of a vaporized oil and/or oil fraction (preferably
vaporized liquefied petroleum gas, gasoline, diesel, kerosene or
naphtha) as a liftgas may have the advantage that the liftgas can
simultaneously act as a hydrogen donor and may prevent or reduce
coke formation. In an especially preferred embodiment both steam as
well as vaporized oil and/or a vaporized oil fraction (preferably
liquefied petroleum gas, vaporized gasoline, diesel, kerosene or
naphtha) are used as a liftgas.
[0080] When the cellulosic material is a solid cellulosic material
and this solid cellulosic material is introduced at the bottom of
the riser reactor, it can be advantageous to increase the residence
time of the cellulosic material at that part of the riser reactor
by increasing the diameter of the riser reactor at the bottom.
Hence in a preferred embodiment the riser reactor comprises a riser
reactor pipe and a bottom section, which bottom section has a
larger diameter than the riser reactor pipe, and wherein a solid
cellulosic material is supplied to the riser reactor in the bottom
section.
[0081] The bottom section having the larger diameter may for
example have the form of a lift pot.
[0082] Preferably the total average residence time of the
cellulosic material in the riser reactor lies in the range from
equal to or more than 1.0 seconds, more preferably from equal to or
more than 1.5 seconds, still more preferably from equal to or more
than 2.0 seconds to equal to or less than 5.0 seconds, preferably
to equal to or less than 4.0 seconds, most preferably to equal to
or less than 2.5 seconds. Residence time as referred to in this
patent application is based on the vapour residence at outlet
conditions, that is, residence time includes not only the residence
time of a specified feed (such as the FCC feedstock) but also the
residence time of its conversion products.
[0083] Preferably the temperature in the riser reactor, where the
FCC feedstock is contacted with the FCC catalyst, lies in the range
from equal to or more than 400.degree. C., more preferably from
equal to or more than 450.degree. C., still more preferably from
equal to or more than 480.degree. C., to equal to or less than
800.degree. C., more preferably to equal to or less than
700.degree. C., still more preferably to equal to or less than
600.degree. C. and most preferably to equal to or less than
550.degree. C.
[0084] Preferably the pressure in the riser reactor ranges from
equal to or more than 0.05 MPa to equal to or less than 1 MPa, more
preferably from equal to or more than 0.1 MPa to equal to or less
than 0.6 MPa.
[0085] The weight ratio of FCC catalyst to FCC feedstock (that is
the total FCC feedstock of cellulosic material and hydrocarbon
co-feed) will herein also be referred to as catalyst to feed ratio
(catalyst:feed ratio). This catalyst to feed weight ratio
preferably lies in the range from equal to or more than 1:1, more
preferably from equal to or more than 2:1 and most preferably from
equal to or more than 3:1 to equal to or less than 150:1, more
preferably to equal to or less than 100:1, most preferably to equal
to or less than 50:1.
[0086] In step a) preferably one or more hydrocarbon products and a
spent FCC catalyst may be produced. The one or more hydrocarbon
product(s) comprise at least a distillate product, but may also
include one or more other product(s). By a hydrocarbon product is
herein understood a product comprising one or more hydrocarbon
compounds.
[0087] In step b) such one or more hydrocarbon product(s)--which
hydrocarbon product(s) comprise least part of the distillate
product--can be separated from the spent FCC catalyst.
[0088] Step b) (also referred to herein as separation step) is
preferably carried out with the help of one or more cyclone
separators and/or one or more swirl tubes. Suitable ways of
carrying out the separation step are for example described in the
Handbook titled "Fluid Catalytic Cracking; Design, Operation, and
Troubleshooting of FCC Facilities" by Reza Sadeghbeigi, published
by Gulf Publishing Company, Houston Tex. (1995), especially pages
219-223 and the Handbook "Fluid Catalytic Cracking technology and
operations", by Joseph W. Wilson, published by PennWell Publishing
Company (1997), chapter 3, especially pages 104-120, and chapter 6,
especially pages 186 to 194, herein incorporated by reference. The
cyclone separators are preferably operated at a velocity in the
range from 18 to 80 meters/second, more preferably at a velocity in
the range from 25 to 55 meters/second.
[0089] Step b) may further comprise stripping of the spent FCC
catalyst. In such a stripping step the spent FCC catalyst may be
stripped to recover any products absorbed on the spent FCC catalyst
before forwarding the spent FCC catalyst to the regeneration in
step c). These products may be recycled and/or added to the one or
more hydrocarbon product(s) obtained from step a)
[0090] In a preferred embodiment the one or more hydrocarbon
product(s) obtained in step a) and/or step b) are subsequently
fractionated to produce one or more product fractions.
[0091] Fractionation may be carried out in any manner known to the
skilled person in the art to be suitable for fractionation of
products from a catalytic cracking reactor. For example the
fractionation may be carried out as described in the Handbook
titled "Fluid Catalytic Cracking technology and operations", by
Joseph W. Wilson, published by PennWell Publishing Company (1997),
chapter 8, especially pages 223 to 235, herein incorporated by
reference.
[0092] The one or more hydrocarbon product(s) are preferably
obtained as gaseous hydrocarbon products from step (a) and/or step
(b). These gaseous hydrocarbon products can subsequently be
separated into various gas and liquid products in one or more
fractionation units.
[0093] Preferably a cooler and/or fractionator is used to cool the
gaseous hydrocarbon products obtained from step (a) and to condense
any heavy liquid products. The fractionator preferably comprises a
distillation tower, which distillation tower comprising a bottom
section (sometimes referred to as flash zone) at the bottom of the
tower; a heavy cycle oil (HCO) section, a light cycle oil (LCO)
section and a top section.
[0094] In the light cycle oil (LCO) section of the distillation
tower the distillate product may be separated from the remainder of
the hydrocarbon products. By a distillate product is herein
preferably understood a hydrocarbon-compound-containing composition
of which at least 80 wt %, more preferably at least 90 wt % has a
boiling temperature at 0.1 MPa in the range from equal to or more
than 221.degree. C. to less equal to or less than 370.degree.
C.
[0095] From the top section of the distillation tower, naphtha
products (herein also referred to as gasoline-containing products)
and so-called dry gas can be withdrawn. By naphtha product(s) or
gasoline-containing-product(s) are herein preferably understood
hydrocarbon-compound-containing compositions of which at least 80
wt %, more preferably at least 90 wt % has a boiling temperature at
0.1 MPa in the range from equal to or more than 30.degree. C. to
less than 221.degree. C.
[0096] Step c) (also referred to herein as regeneration step)
preferably comprises regenerating the spent FCC catalyst in a
regenerator to produce a regenerated FCC catalyst. More preferably
step c) comprises contacting the spent FCC catalyst with an oxygen
containing gas in a regenerator at a temperature of equal to or
more than 550.degree. C. to produce a regenerated FCC catalyst,
heat and carbon dioxide. During the regeneration coke, that can be
deposited on the FCC catalyst as a result of the catalytic cracking
reaction(s) in step a) and/or step d), is burned off to restore the
catalyst activity.
[0097] Preferably the catalyst regenerator comprises an essentially
vertical-arranged, essentially cylindrical vessel that defines the
regeneration zone and wherein the spent FCC catalyst is maintained
as a fluidized bed by the upward passage of the oxygen-containing
gas, such as air.
[0098] Preferably the spent FCC catalyst is regenerated at a
temperature in the range from equal to or more than 575.degree. C.,
more preferably from equal to or more than 600.degree. C., to equal
to or less than 950.degree. C., more preferably to equal to or less
than 850.degree. C. In a most preferred embodiment the temperature
within the regeneration zone is preferably maintained in the range
of from equal to or more than 620.degree. C. to equal to or less
than 780.degree. C., and more preferably in the range of from equal
to or more than 670.degree. C. to equal to or less than 750.degree.
C. Preferably the spent FCC catalyst is regenerated at a pressure
in the range from equal to or more than 0.05 MPa to equal to or
less than 1 MPa, more preferably from equal to or more than 0.1 MPa
to equal to or less than 0.6 MPa.
[0099] The residence time of the spent FCC catalyst within the
regeneration zone is preferably in the range of from equal to or
more than 1 minute to equal to or less than 6 minutes, and more
preferably from equal to or more than 2 minutes to equal to or less
than 4 minutes. The coke content on the regenerated FCC catalyst is
less than the coke content on the spent FCC catalyst. Preferably
the coke content on the regenerated FCC catalyst is equal to or
less than 0.5 wt. %, based on the total weight of the regenerated
FCC catalyst. More preferably the coke content of the regenerated
FCC catalyst lies in the range of from equal to or more than 0.01
wt. % to equal to or less than 0.5 wt. % based on the total weight
of the regenerated FCC catalyst. Most preferably the coke
concentration on the regenerated FCC catalyst lies in the range of
equal to or more than 0.01 wt. % to equal to or less than 0.1 wt.
%, based on the total weight of the regenerated FCC catalyst.
[0100] In a preferred embodiment a side stream of fresh FCC
catalyst is added to the regenerator to make-up for possible losses
of the FCC catalyst in the process, such as for example possible
losses of FCC catalyst in any cyclone(s) after the reactor(s)
and/or in any optional cyclone(s) after the regenerator. In
addition the side stream of fresh FCC catalyst may be used to
replace part of the spent FCC catalyst with fresh FCC catalyst to
make-up for any loss in catalyst activity in the process. If part
of the spent FCC catalyst is replaced by fresh FCC catalyst, such
part of the spent FCC catalyst is preferably equal to or less than
10 wt %, more preferably equal to or less than 5 wt % and most
preferably equal to or less than 1 wt %, based on the total weight
of catalyst present in the regenerator.
[0101] By a fresh FCC catalyst is herein understood an FCC catalyst
that has not been used yet in a fluidized catalytic cracking
reaction.
[0102] The oxygen containing gas may be any oxygen containing gas
known to the skilled person to be suitable for use in a
regenerator. For example the oxygen containing gas may be air or
oxygen-enriched air. By oxygen enriched air is herein understood
air comprising more than 21 vol. % oxygen (O.sub.2), more
preferably air comprising equal to or more than 22 vol. % oxygen,
based on the total volume of air.
[0103] Any heat produced in the exothermic regeneration step is
preferably employed to provide energy for feed vaporization and the
endothermic catalytic cracking in step a) and/or step d). In
addition the heat produced can be used to heat water and/or
generate steam. The steam may be used elsewhere, for example as a
liftgas in the riser reactor.
[0104] In a preferred embodiment step c) further comprises
separating the produced regenerated FCC catalyst from any
side-products produced in the regeneration, such as for example
carbon dioxide. Preferably such separation is carried out with the
help of one or more cyclone separators and/or swirl tubes.
[0105] The regenerated FCC catalyst is at least partly forwarded to
step d).
[0106] In step d) at least part of the regenerated FCC catalyst is
contacted with an intermediate reactor feedstock in an intermediate
reactor at a temperature of equal to or more than 500.degree. C. to
produce one or more C2-C4 olefins and a used regenerated FCC
catalyst.
[0107] The intermediate reactor feedstock is preferably a feedstock
comprising one or more hydrocarbon compounds of which one or more
hydrocarbon compounds at least 80 wt %, more preferably at least 90
wt % has a boiling temperature at 0.1 MPa of equal to or below
221.degree. C., more preferably equal to or below 204.degree. C.
More preferably the intermediate reactor feedstock is a feedstock
comprising one or more hydrocarbon compounds of which hydrocarbon
compounds at least 80 wt %, more preferably at least 90 wt % has a
boiling temperature at 0.1 MPa in the range from equal to or more
than 30.degree. C. to less than 221.degree. C., more preferably in
the range from equal to or more than 32.degree. C. to equal to or
less than 204.degree. C.
[0108] Examples of refinery streams that may be used as the
intermediate reactor feedstock include the so-called naphtha
products described herein above. Such naphtha products can for
example be formed by one or more fraction(s) of the products of a
fluidized catalytic cracking reactor, of which fraction(s) at least
80 wt %, more preferably at least 90 wt % boils in the range from
equal to or more than 30.degree. C. to less than 221.degree. C.
[0109] Examples of naphtha products include light-light-cycle oil
(LLCO, sometimes also referred to as heavy-catalytically-cracked
gasoline (HCCG) or heavy-catalytically-cracked naphtha);
catalytically-cracked gasoline (CCG, sometimes also referred to as
heart-cut gasoline or catalytically-cracked naphtha); and a light
catalytically-cracked gasoline (LCCG, sometimes also referred to as
catalytically-cracked tops or light catalytically-cracked
naphtha).
[0110] Further examples of refinery streams that may be used as the
intermediate reactor feedstock include, coker gasoline, visbreaker
gasoline, light straight run gasoline, heavy straight run gasoline,
raffinates, hydrowaxes, Fischer-Tropsch waxes and/or mixtures of
these.
[0111] In an especially preferred embodiment the intermediate
reactor feedstock comprises a product produced in the riser reactor
in step a), for example a gasoline-containing product or naphtha
product produced in the riser reactor of step a). Hence preferably
step a) comprises contacting a FCC feedstock with a FCC catalyst at
a temperature of equal to or more than 400.degree. C. in a riser
reactor to produce a gasoline-containing-product, a distillate
product and a spent FCC catalyst; and at least part of the
gasoline-containing-product is used as an intermediate reactor
feedstock in step d).
[0112] In a preferred embodiment the intermediate reactor feedstock
comprises one or more olefins, for example comprising in the range
from equal to or more than 20 wt % of one or more olefins, more
preferably equal to or more than 45 wt % of one or more olefins, to
equal to or less than 65 wt % of one or more olefins, more
preferably to equal to or less than 55 wt % of one or more olefins,
based on the total weight of intermediate reactor feedstock. By an
olefin is herein understood a hydrocarbon compound wherein two or
more carbon atoms are bound to another carbon atom by a double
bond. Preferably such olefins contained in the intermediate reactor
feedstock are C5.sup.+-olefins. By C5.sup.+-olefins are herein
understood olefins having equal to or more than 5 carbon atoms.
Examples of such C5.sup.+-olefins include pentenes, pentadienes,
hexenes and hexadienes. An example of such an olefin-containing
intermediate reactor feedstock is an olefin-containing naphtha
product (for example catalytically cracked gasoline). Preferably
the intermediate reactor feedstock is therefore a naphtha product
(also referred to herein as gasoline-containing-product) comprising
in the range from equal to or more than 20 wt % to equal to or less
than 65 wt % of one or more olefins, based on the total weight of
naphtha product. Such a naphtha product comprising one or more
olefins may be difficult to blend with other fuel components. The
process according to the invention can conveniently convert such an
olefin-containing naphtha product into a blendable gasoline
component and one or more C2-C4 olefins.
[0113] In a preferred embodiment the present invention therefore
also provides a process for the preparation of a biofuel and/or a
biochemical, comprising
a) contacting a FCC feedstock with a FCC catalyst at a temperature
of equal to or more than 400.degree. C. in a riser reactor to
produce a distillate product, a spent FCC catalyst, and optionally
a first gasoline-containing-product, wherein the FCC feedstock
comprises a cellulosic material and a hydrocarbon co-feed; b)
separating at least part of the distillate product from the spent
FCC catalyst; c) regenerating the spent FCC catalyst to produce a
regenerated FCC catalyst; d) contacting an intermediate reactor
feedstock, which intermediate reactor feedstock may optionally
comprise the first gasoline-containing-product, with at least part
of the regenerated FCC catalyst at a temperature of equal to or
more than 500.degree. C. in an intermediate reactor to produce a
used regenerated FCC catalyst, one or more C2-C4 olefins and a
second gasoline-containing-product, which second
gasoline-containing-product comprises one or more hydrocarbon
compounds, and wherein at least 80 wt % of such one or more
hydrocarbon compounds has a boiling temperature at 0.1 MPa in the
range from equal to or more than 30.degree. C. to less than
221.degree. C.; e) separating at least part of the second
gasoline-containing-product and at least part of the one or more
C2-C4 olefins from the used regenerated catalyst; f) using at least
part of the used regenerated FCC catalyst as FCC catalyst in step
a); wherein at least part of the first gasoline-containing-product
or at least part of the second gasoline-containing-product is
blended with one or more other components to prepare a biofuel
and/or a biochemical.
[0114] In addition the intermediate reactor feedstock may comprise
further biological feed components such as vegetable oils, used
cooking oil, animal fat and/or mixtures thereof. Such vegetable
oils, used cooking oil and/or animal fat may optionally be upgraded
or pretreated, for example by means of a hydrotreatment (including
for example hydrogenation and/or hydrodeoxygenation). Suitable
plant oils (vegetable oils) include for example rapeseed oil, palm
oil, coconut oil, corn oil, soya oil, safflower oil, sunflower oil,
linseed oil, olive oil and peanut oil. Suitable animal fats include
for example pork lard, beef fat, mutton fat and chicken fat. If any
biological feed component is present, such biological feed
component is preferably present in the intermediate reactor
feedstock in an amount of equal to or more than 1 wt % to equal to
or less than 40 wt %, more preferably from equal to or more than 5
wt % to equal to or less than 30 wt %, most preferably from equal
to or more than 10 wt % to equal to or less than 20 wt %, based on
the total weight of the intermediate reactor feedstock.
[0115] The intermediate reactor is preferably an intermediate
reactor comprising a fluidized catalyst. More preferably the
intermediate reactor is a fluidized bed reactor or a riser reactor.
In case the intermediate reactor is a riser reactor, the
intermediate reactor in step d) could be referred to as the second
riser reactor, since the riser reactor in step a) would form the
first riser reactor. When the intermediate reactor is a fluidized
bed reactor it is preferably a so-called dense phase reactor, dense
bed reactor or a fixed fluidized bed reactor.
[0116] If the intermediate reactor is a fluidized bed reactor, this
fluidized bed reactor can for example comprise a vessel that
defines a fluidized bed reaction zone. Regenerated FCC catalyst may
be contained in this reaction zone where it may be fluidized by the
introduction of the intermediate reactor feedstock and, optionally,
steam.
[0117] If the intermediate reactor is a riser reactor, the riser
reactor may for example be any type or riser reactor as described
for step a), including for example an internal or external riser
reactor and/or a riser reactor including a liftpot. If a liftgas is
used, any liftgas as mentioned for step a) may be used, but steam
may be most preferred as a liftgas.
[0118] Preferably the temperature in the intermediate reactor,
where the intermediate reactor feedstock is contacted with the
regenerated FCC catalyst, lies in the range from equal to or more
than 500.degree. C., more preferably from equal to or more than
520.degree. C., and most preferably equal to or more than
550.degree. C. to equal to or less than 900.degree. C., more
preferably to equal to or less than 850.degree. C., still more
preferably to equal to or less than 800.degree. C. and most
preferably to equal to or less than 750.degree. C.
[0119] In a preferred embodiment the temperature in the
intermediate reactor in step d) is higher than the temperature in
the riser reactor in step a).
[0120] Preferably the pressure in the intermediate reactor ranges
from equal to or more than 0.05 MPa (MegaPascal) to equal to or
less than 1 MPa, more preferably from equal to or more than 0.1 MPa
to equal to or less than 0.6 MPa.
[0121] In a preferred embodiment the intermediate reactor feedstock
and steam are simultaneously fed into the reaction zone of the
intermediate reactor to be contacted with the regenerated FCC
catalyst. The use of steam as a co-feed or liftgas may
advantageously improve selectivity towards C2-C4 olefins. When
steam is used, the weight ratio of steam to intermediate reactor
feedstock lies preferably in the range of equal to or more than
0.1:1 to equal to or less than 15:1. More preferably, the weight
ratio of steam to intermediate reactor feedstock lies in the range
of from 0.2:1 to 10:1.
[0122] In step d) preferably one or more hydrocarbon products and a
used regenerated FCC catalyst may be produced. The one or more
hydrocarbon product(s) comprise at least one or more C2-C4 olefins,
but may also include one or more other hydrocarbon product(s).
[0123] In step (e) such one or more hydrocarbon product(s) can be
separated from the used regenerated FCC catalyst in any manner
known to the person skilled in the art. For example, the used
regenerated FCC catalyst may be separated from the one or more
hydrocarbon products in the same manner as the such one or more
hydrocarbon product(s)--which hydrocarbon product(s) may comprise
least part of the distillate--can be separated from the spent FCC
catalyst in step (b). For example such separation can be carried
out with the help of one or more cyclone separators and/or one or
more swirl tubes. In addition, a stripping step may be incorporated
in step e), wherein the used regenerated FCC catalyst may be
stripped to recover any products absorbed on the used regenerated
FCC catalyst before using at least part of the used regenerated FCC
catalyst as FCC catalyst in step a). These products may be recycled
and/or added to the one or more hydrocarbon product(s) obtained in
step d).
[0124] In a preferred embodiment the one or more hydrocarbon
product(s) obtained in step d) are subsequently cooled and/or
fractionated to produce one or more product fractions, one of which
would be the one or more C2-C4 olefins.
[0125] By olefins are herein preferably understood hydrocarbon
compounds having one or more unsaturated bond(s). By C2-C4 olefins
are herein understood olefins having in the range from equal to or
more than 2 to equal to or less than 4 carbon atoms. Preferably the
C2-C4 olefins are olefins chosen from the group consisting of
ethene, propene, 1-butene, 2-butene, butadiene and methyl-propene.
Most preferred olefins are ethene and propene.
[0126] In step f) at least part of the used regenerated FCC
catalyst is recycled and used as FCC catalyst in step a).
[0127] Advantageously the regenerated FCC catalyst is partially
deactivated during step d) prior to using the used regenerated FCC
catalyst in the riser reactor in step a). What is meant by partial
deactivation is that the used regenerated FCC catalyst will contain
a higher concentration of coke than the regenerated FCC catalyst.
The use of such partially deactivated catalyst (i.e. the already
partially coked catalyst comprising) in step a) advantageously
allows one to operate at a lower temperature and lower catalyst
activity such that the desired distillate product can be made in
higher yields. The coke concentration on the used regenerated FCC
catalyst is greater than the coke concentration on the regenerated
FCC catalyst, but it is less than that of the separated spent FCC
catalyst. Preferably, the coke content of the used regenerated FCC
catalyst is in the range of from equal to or more than 0.1 wt. % to
equal to or less than 1 wt. %, and, more preferably, from equal to
or more than 0.1 wt. % to equal to or less than 0.6 wt. %.
[0128] The amount of regenerated FCC catalyst produced in step c)
that is provided to the intermediate reactor in step d) may vary
extensively and may for example lie in the range from equal to or
more than 1 wt. % to equal to or less than 100 wt. %, based on the
total weight of regenerated FCC catalyst produced in step c). More
preferably the amount of regenerated FCC catalyst produced in step
c) that is provided to the intermediate reactor in step d) may lie
in the range from equal to or more than 10 wt. %, still more
preferably equal to or more than 50 wt. % to equal to or less than
100 wt. %, possibly equal to or less than 90 wt. %, based on the
total weight of regenerated FCC catalyst produced in step c).
[0129] To assist in providing for the control of the process
conditions within the riser reactor in step a) and/or to provide
for the desired product mix, the regenerated FCC catalyst produced
in step c) can be divided into at least a first portion that is
passed to the intermediate reactor in step d) and a second portion
that is passed to the riser reactor in step a). In such a case the
second portion preferably comprises equal to or less than 50 wt %,
based on the total weight of regenerated FCC catalyst produced in
step c). If a second portion is present, the second portion more
preferably lies in the range from equal to or more than 10 wt % to
equal to or less than 50 wt %, based on the total weight of the FCC
catalyst produced in step c).
[0130] The one or more hydrocarbon product(s), such as for example
the distillate product and/or the one or more C2-C4 olefins,
obtained in the process according to the invention may
advantageously be used to produce one or more biofuel components
and/or one or more biochemical components.
[0131] For example, the C2-C4 olefins produced according to the
invention may advantageously be used to produce bio-polymers, such
as for example biological polypropylene and/or biological
polyethylene.
[0132] The distillate product produced according to the invention
may advantageously be used as a biofuel component or it may undergo
further process steps to be converted into a biofuel component.
[0133] The biofuel components and/or biochemical components
produced according to the process of the present invention will
have increased levels of carbon-14 isotope and are advantageously
more sustainable than their conventional counterparts.
[0134] In one embodiment at least part of the distillate product
produced in the process of the invention is hydrotreated before
being used as a biofuel component. Such hydrotreatment may include
for example hydrodesulfurization, hydrodeoxygenation,
hydrodenitrogenation and/or hydrogenation. In a preferred
embodiment the distillate product produced is
hydrodeoxygenated.
[0135] The hydrotreatment (such as the hydrodeoxygenation)
preferably comprises contacting the distillate product with
hydrogen in the presence of a hydrotreatment catalyst (such as a
hydrodeoxygenation catalyst) at a temperature in the range from
equal to or more than 200.degree. C., preferably equal to or more
than 250.degree. C., to equal to or less than 450.degree. C.,
preferably equal to or less than 400.degree. C.; at a total
pressure in the range of equal to or more than 1 MPa to equal to or
less than 35 MPa; and/or at a partial hydrogen pressure in the
range of equal to or more than 0.2 MPa to equal to or less than 35
MPa.
[0136] Any hydrodeoxygenation catalyst used can be any type of
hydrodeoxygenation catalyst known by the person skilled in the art
to be suitable for this purpose. The hydrodeoxygenation catalyst
preferably comprises a catalyst support and one or more active
elements. The active elements may include metals such as Nickel
(Ni), Chromium (Cr), Molybdenum (Mo), and Tungsten (W), Cobalt
(Co), Platinum (Pt), Palladium (Pd), Rhodium (Rh), Ruthenium (Ru),
Iridium (Ir), Osmium (Os), Copper (Cu), iron (Fe), Zink (Zn),
Gallium (Ga), Indium (In) and Vanadium (V) in elementary form,
alloys or mixtures of one or more thereof such as.
[0137] Preferably the hydrodeoxygenation catalyst is a catalyst
comprising Ruthenium, Rhenium, Cobalt, Nickel, Copper, Tungsten
and/or alloys or mixtures of Ruthenium, Rhenium, Cobalt, Nickel,
Tungsten and/or Copper, such as for example Rh--Co-- and/or Ni--Cu,
on a catalyst carrier that is inert at the reaction conditions. The
carrier preferably may comprise a refractory oxide or mixtures
thereof, preferably alumina, amorphous silica-alumina, titania or
silica, ceria, zirconia, or it may comprise an inert component such
as carbon or silicon carbide or carbon. Carriers that were found
inert are ZrO.sub.2, CeO.sub.2, CeO.sub.2 and/or mixtures thereof
such as CeO.sub.2--ZrO.sub.2, silicon carbide and/or carbon. In
some cases it may be advantageous to use a sulphided
hydrodeoxygenation catalyst. If a sulphided hydrodeoxygenation
catalyst is used, the catalyst may be sulphided in-situ or ex-situ.
In the case of in-situ sulphiding, a sulphur source, usually
hydrogen sulphide or a hydrogen sulphide precursor, is preferably
supplied to the catalyst during operation of the hydrodeoxygenation
process. Most preferred are hydrodeoxygenation catalysts comprising
rhodium on alumina(Rh/Al.sub.2O.sub.3), rhodium on silica
(Rh/SiO.sub.2), rhodium on zirconia (Rh/ZrO.sub.2), rhodium-cobalt
on alumina (RhCo/Al.sub.2O.sub.3), rhodium-cobalt on silica
(RhCo/SiO.sub.2), rhodium-cobalt on zirconia (RhCo/ZrO.sub.2),
nickel on alumina(Ni/Al.sub.2O.sub.3), nickel on silica
(Ni/SiO.sub.2), nickel on zirconia (Ni/ZrO.sub.2), nickel-copper on
alumina (NiCu/Al.sub.2O.sub.3), nickel-copper on silica
(NiCu/SiO.sub.2), nickel-copper on zirconia (NiCu/ZrO.sub.2),
nickel-tungsten on alumina (NiW/Al.sub.2O.sub.3), nickel-tungsten
on silica (NiW/SiO.sub.2), nickel-tungsten on zirconia
(NiW/ZrO.sub.2), cobalt on alumina(Co/Al.sub.2O.sub.3), cobalt on
silica (Co/SiO.sub.2), cobalt on zirconia (Co/ZrO.sub.2),
cobalt-molybdenum on silica (CoMo/Si.sub.2O.sub.3),
cobalt-molybdenum on zirconia(CoMo/ZrO.sub.2), cobalt-molybdenum on
alumina(CoMo/Al.sub.2O.sub.3).
[0138] The biofuel component and/or biochemical component can be
blended with one or more other components to produce a biofuel
and/or a biochemical. Examples of one or more other components with
which the biofuel component and/or biochemical component may be
blended include anti-oxidants, corrosion inhibitors, ashless
detergents, dehazers, dyes, lubricity improvers and/or mineral fuel
components, but also conventional petroleum derived gasoline,
diesel and/or kerosene fractions.
[0139] By a biofuel respectively a biochemical is herein understood
a fuel or a chemical that is at least party derived from a
renewable energy source.
[0140] In FIG. 1 one embodiment according to the invention is
illustrated. In FIG. 1, a FCC feedstock comprising cellulosic
material and hydrocarbon co-feed (102) and steam (104) are
introduced into the bottom of a first riser reactor (106). In the
bottom of the first riser reactor (106), the FCC feedstock (102)
and the steam (104) are mixed with "fresh" regenerated FCC catalyst
(108) and used regenerated FCC catalyst (110). In the first reactor
riser (106) the FCC feedstock (102) is catalytically cracked to
produce one or more hydrocarbon products comprising distillate and
a spent FCC catalyst. The mixture of one or more hydrocarbon
products, spent FCC catalyst, steam, and any residual non-cracked
FCC feedstock is forwarded from the top of the first riser reactor
(106) into a reactor vessel (112), comprising a first cyclone
separator (114) closely coupled with a second cyclone separator
(116). One or more products (118) are retrieved via the top of the
second cyclone separator (116) and optionally forwarded to a
fractionator (not shown). Spent FCC catalyst is retrieved from the
bottom of the cyclone separators (114 and 116) and forwarded to a
stripper (120) where further hydrocarbon products are stripped off
the spent FCC catalyst.
[0141] The spent and stripped FCC catalyst (122) is forwarded to a
regenerator (124), where the spent and stripped FCC catalyst is
contacted with air (126) to produce a regenerated FCC catalyst
(108). A first part of the regenerated FCC catalyst (108a) is
recycled to the bottom of the first riser reactor (106). A second
part of the regenerated FCC catalyst (108b) is forwarded to the
bottom of an intermediate riser reactor (130). In the bottom of the
intermediate riser reactor (130) the second part of the regenerated
FCC catalyst (108b) is contacted with an intermediate reactor
feedstock (132) consisting of gasoline, and a second stream of
steam (134). In the intermediate riser reactor (130) the
intermediate reactor feedstock (132) is catalytically cracked to
produce one or more hydrocarbon products comprising C2-C4 olefins
and a used regenerated FCC catalyst. The mixture of one or more
hydrocarbon products, used regenerated FCC catalyst, steam, and any
residual non-cracked intermediate reactor feed is forwarded from
the top of the intermediate riser reactor (130) into a second
reactor vessel (136), comprising a first cyclone separator (138)
closely coupled with a second cyclone separator (140). One or more
products (142) are retrieved via the top of the second cyclone
separator (140) and optionally forwarded to a fractionator (not
shown). Used regenerated FCC catalyst is retrieved from the bottom
of the cyclone separators (138 and 140) and forwarded to a stripper
(144) where further hydrocarbon products are stripped off the used
regenerated FCC catalyst. Subsequently the stripped used
regenerated FCC catalyst is recycled to the bottom of the first
riser reactor (106) as FCC catalyst stream (110).
* * * * *