U.S. patent application number 14/560129 was filed with the patent office on 2015-06-25 for method for oxygenate conversion.
This patent application is currently assigned to ExxonMobil Research and Engineering Company. The applicant listed for this patent is Patricia A. BIELENBERG, Michel DAAGE, Ramesh GUPTA, Karlton J. HICKEY, Brett LOVELESS, Stephen J. McCarthy, Brian PETERSON, Michael Francis RATERMAN, Rohit VIJAY. Invention is credited to Patricia A. BIELENBERG, Michel DAAGE, Ramesh GUPTA, Karlton J. HICKEY, Brett LOVELESS, Stephen J. McCarthy, Brian PETERSON, Michael Francis RATERMAN, Rohit VIJAY.
Application Number | 20150175898 14/560129 |
Document ID | / |
Family ID | 52134438 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150175898 |
Kind Code |
A1 |
McCarthy; Stephen J. ; et
al. |
June 25, 2015 |
METHOD FOR OXYGENATE CONVERSION
Abstract
Methods for organic compound conversion are disclosed.
Particular methods include providing a first mixture comprising
.gtoreq.10.0 wt % of at least one oxygenate, based on the weight of
the first mixture; contacting said first mixture in at least a
first moving bed reactor with a catalyst under conditions effective
to covert at least a portion of the first mixture to a product
stream comprising water, hydrogen, and one or more hydrocarbons;
and separating from said product stream (i) at least one light
stream and ii) at least one heavy stream, wherein the method is
characterized by a recycle ratio of .ltoreq.5.0.
Inventors: |
McCarthy; Stephen J.;
(Center Valley, PA) ; VIJAY; Rohit; (Bridgewater,
NJ) ; RATERMAN; Michael Francis; (Doylestown, PA)
; PETERSON; Brian; (Fogelsville, PA) ; HICKEY;
Karlton J.; (Boothwyn, PA) ; DAAGE; Michel;
(Hellertown, PA) ; LOVELESS; Brett; (Maplewood,
NJ) ; GUPTA; Ramesh; (Berkeley Heights, NJ) ;
BIELENBERG; Patricia A.; (Lebanon, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
McCarthy; Stephen J.
VIJAY; Rohit
RATERMAN; Michael Francis
PETERSON; Brian
HICKEY; Karlton J.
DAAGE; Michel
LOVELESS; Brett
GUPTA; Ramesh
BIELENBERG; Patricia A. |
Center Valley
Bridgewater
Doylestown
Fogelsville
Boothwyn
Hellertown
Maplewood
Berkeley Heights
Lebanon |
PA
NJ
PA
PA
PA
PA
NJ
NJ
NJ |
US
US
US
US
US
US
US
US
US |
|
|
Assignee: |
ExxonMobil Research and Engineering
Company
Annandale
NJ
|
Family ID: |
52134438 |
Appl. No.: |
14/560129 |
Filed: |
December 4, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61918984 |
Dec 20, 2013 |
|
|
|
61918994 |
Dec 20, 2013 |
|
|
|
61919013 |
Dec 20, 2013 |
|
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Current U.S.
Class: |
585/408 |
Current CPC
Class: |
Y02P 30/40 20151101;
B01J 35/1057 20130101; B01J 35/109 20130101; B01J 29/7049 20130101;
B01J 29/40 20130101; C10L 1/06 20130101; B01J 38/12 20130101; B01J
35/10 20130101; B01J 35/1042 20130101; B01J 37/0009 20130101; B01J
21/04 20130101; B01J 2229/20 20130101; B01J 2229/186 20130101; B01J
29/90 20130101; C10L 2270/023 20130101; B01J 27/14 20130101; Y02P
30/20 20151101; B01J 35/108 20130101; B01J 29/7057 20130101; C10G
3/55 20130101; B01J 2229/42 20130101; C07C 1/20 20130101; B01J
35/1023 20130101; B01J 35/1014 20130101; C07C 2529/70 20130101;
B01J 35/1019 20130101; B01J 38/02 20130101; C07C 1/22 20130101;
C10L 2200/0423 20130101; B01J 23/06 20130101; C10G 3/49 20130101;
Y02P 20/584 20151101; C07C 2523/06 20130101; B01J 37/0201 20130101;
B01J 35/1038 20130101; B01J 37/28 20130101; C10G 3/45 20130101;
C07C 2529/06 20130101; B01J 29/405 20130101; C10L 2200/0469
20130101; C07C 2529/40 20130101; B01J 29/061 20130101; C07C 1/20
20130101; C07C 11/02 20130101; C07C 1/20 20130101; C07C 15/02
20130101 |
International
Class: |
C10G 3/00 20060101
C10G003/00; C10L 1/06 20060101 C10L001/06 |
Claims
1. A method for organic compound conversion, comprising: a)
providing a first mixture comprising .gtoreq.10.0 wt % of at least
one oxygenate, based on the weight of the first mixture; b)
contacting said first mixture in at least a first moving bed
reactor with a catalyst under conditions effective to covert at
least a portion of the first mixture to a product stream comprising
water, hydrogen, and one or more hydrocarbons; and c) separating
from said product stream (i) at least one light stream and ii) at
least one heavy stream, wherein the method is characterized by a
recycle ratio of .ltoreq.5.0.
2. The method of claim 1, further comprising contacting the product
stream with a liquid phase quench medium.
3. The method of claim 1, wherein the catalyst comprises a
phosphorous-stabilized catalyst.
4. The method of claim 1, wherein the first mixture comprises
.gtoreq.about 5 wt % H.sub.2O and the catalyst comprises a
phosphorous-stabilized catalyst.
5. The method of claim 1, further comprising separating from the at
least one light stream a light gas stream comprising C.sub.5-
hydrocarbons and hydrogen and a product-enriched stream.
6. The method of claim 1, wherein the at least one light stream
comprises .gtoreq.30 wt % C.sub.5+, hydrocarbons, based on the
weight of the light stream.
7. The method of claim 6, wherein the C.sub.5+ hydrocarbons
comprise .gtoreq.about 30 wt % aromatic hydrocarbons.
8. The method of claim 7, further comprising separating from the at
least one light stream at least one aromatic-enriched hydrocarbon
stream and at least one aromatic-depleted hydrocarbon stream.
9. The method of claim 1, wherein the at least one light stream
comprises .gtoreq.30 wt % of one or more olefins, based on the
weight of the light stream.
10. The method of claim 9, further comprising separating from the
at least one light stream at least one olefin-enriched hydrocarbon
stream and at least one olefin-depleted hydrocarbon stream.
11. The method of claim 1, further comprising a second moving bed
reactor in fluid communication with the first moving bed
reactor.
12. The method of claim 11, wherein a space-time velocity of the at
least one oxygenate in the first moving bed reactor is greater than
a space time velocity of the at least one oxygenate in the second
moving bed reactor.
13. The method of claim 11, further comprising a third moving bed
reactor in fluid communication with the second moving bed
reactor.
14. The method of claim 13, wherein a space-time velocity of the at
least one oxygenate in the second moving bed reactor is greater
than a space time velocity of the third moving bed reactor.
15. A method for organic compound conversion, comprising: a)
providing a first mixture comprising .gtoreq.10.0 wt % of at least
one oxygenate, based on the weight of the first mixture; b)
contacting said first mixture in a first moving bed reactor with a
first catalyst under conditions effective to covert at least a
portion of the first mixture to a first product stream comprising a
first amount of one or more hydrocarbons; c) contacting said first
product stream in a second moving bed reactor with a second
catalyst under conditions effective to covert at least a portion of
the first product stream to a second product stream comprising
water, hydrogen, and a second amount of one or more hydrocarbons;
and d) separating from said second product stream (i) at least one
light stream, and (ii) at least one heavy stream, wherein the
method is characterized by a recycle ratio of .ltoreq.5.0.
16. The method of claim 15, further comprising contacting the first
and/or the second product stream with a liquid phase quench
medium.
17. The method of claim 15, wherein the first and/or the second
catalyst comprises a phosphorous-stabilized catalyst.
18. The method of claim 1, wherein the first mixture and/or first
product stream comprises .gtoreq.about 5 wt % H.sub.2O and the
first and/or second catalyst comprises a phosphorous-stabilized
catalyst.
19. The method of claim 15, wherein the at least one light stream
comprises .gtoreq.30 wt % C.sub.5+ hydrocarbons, based on the
weight of the light stream.
20. The method of claim 19, wherein the C.sub.5+ hydrocarbons
comprise .gtoreq.about 30 wt % aromatic hydrocarbons.
21. The method of claim 15, further comprising separating from the
at least one light stream at least one aromatic-enriched
hydrocarbon stream and at least one aromatic-depleted hydrocarbon
stream.
22. The method of claim 21, wherein the at least one light stream
comprises .gtoreq.30 wt % of one or more olefins, based on the
weight of the light stream.
23. The method of claim 22, further comprising separating from the
at least one light stream at least one olefin-enriched hydrocarbon
stream and at least one olefin-depleted hydrocarbon stream.
24. The method of claim 15, wherein the first and second catalysts
are the same or different.
25. The method of claim 15, wherein the second amount of one or
more hydrocarbons is greater than the first amount of one or more
hydrocarbons.
26. A method for organic compound conversion, comprising: a)
providing a first mixture comprising .gtoreq.10.0 wt % of at least
one oxygenate, based on the weight of the first mixture; b)
contacting said first mixture in a first moving bed reactor with a
first catalyst under conditions effective to covert at least a
portion of the first mixture to a first product stream comprising
water, hydrogen, and a first amount of one or more hydrocarbons; c)
contacting said first product stream in a second moving bed reactor
with a second catalyst under conditions effective to covert at
least a portion of the first product stream to a second product
stream comprising water, hydrogen, and a second amount of one or
more hydrocarbons; d) contacting said second product stream in a
third moving bed reactor with a third catalyst under conditions
effective to covert at least a portion of the second product stream
to a third product stream comprising water, hydrogen, and a third
amount of one or more hydrocarbons; and e) separating from said
third product stream (i) at least one hydrocarbon-enriched
hydrocarbon stream, and (ii) at least one heavy stream, wherein the
method is characterized by a recycle ratio of .ltoreq.5.0.
27. The method of claim 26, wherein the at least one light stream
comprises .gtoreq.30 wt % C.sub.5+ hydrocarbons, based on the
weight of the light stream.
28. The method of claim 27, wherein the C.sub.5+ hydrocarbons
comprise .gtoreq.about 30 wt % aromatic hydrocarbons.
29. The method of claim 28, further comprising separating from the
at least one light stream at least one aromatic-enriched
hydrocarbon stream and at least one aromatic-depleted hydrocarbon
stream.
30. The method of claim 26, wherein the at least one light stream
comprises .gtoreq.30 wt % of one or more olefins, based on the
weight of the light stream.
31. The method of claim 30, further comprising separating from the
at least one light stream at least one olefin-enriched hydrocarbon
stream and at least one olefin-depleted hydrocarbon stream.
32. The method of claim 26, wherein the first, second and/or third
catalysts are the same or different.
33. The method of claim 26, wherein the second amount of one or
more hydrocarbons is greater than the first amount of one or more
hydrocarbons.
34. The method of claim 26, wherein the third amount of one or more
hydrocarbons is greater than the first and/or second amount of one
or more hydrocarbons.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application Nos. 61/918,984, 61/918,994, and 61/919,013, each filed
on Dec. 20, 2013, the entire contents of each of which are hereby
incorporated by reference herein.
FIELD OF INVENTION
[0002] The invention relates to methods of converting
oxygenate-containing feedstocks to olefins and/or aromatic
hydrocarbons. The method includes a moving bed reactor the use of
which enables a reduced amount of recycle, optionally with liquid
quenching, particularly interstage liquid quenching.
BACKGROUND OF INVENTION
[0003] A variety of industrial processes are known for conversion
of low boiling carbon-containing compounds to higher value
products. One such process, the so-called "MTG process", converts
methanol and/or dimethyl ether to gasoline-range products. The
methanol and/or dimethyl ether are then converted in a series of
reactions that results in formation of a hydrocarbon mixture that
comprises aromatic, paraffinic, and olefinic compounds. This
mixture may be separated into a liquefied petroleum gas (LPG)
fraction and a high-quality gasoline fraction comprising aromatics,
paraffins, and olefins. The typical MTG hydrocarbon product
consists of about olefins and about 50-60% paraffins and 30-50%
aromatics, e.g., xylenes, benzene, toluene, etc.
[0004] Conventionally, methanol is converted to liquid fuels using
either a fixed or fluid bed reactor, and coking is typically not a
significant problem in the process. Tubular fixed bed reactors
immersed in molten salt have also been proposed. Depending on the
design, such reactors have one or more of the following drawbacks,
e.g., relatively inconsistent product yields, low methanol
utilization, low selectivity to desired products, and low catalyst
utilization.
[0005] Low catalyst utilization is typically due to catalyst
deactivation to which fixed and fluid bed reactors are prone. One
mechanism for deactivation mechanism is de-alumination of the
zeolite by steam. This deactivation is permanent and determines the
overall catalyst life. Steam deactivation is most pronounced at the
outlet of the catalyst bed due to higher temperatures, water
partial pressures, and lower coke levels which provides less
protection for the catalyst from steam deactivation. The end of the
catalyst life is determined by the overall activity of the catalyst
and at such time the catalyst must be replaced even though the
catalyst at the top of the fixed bed is still quite active. This
results in only partial catalyst utilization, lower catalyst
efficiency and higher catalyst costs.
[0006] Fixed bed and fluid beds reactors also suffer from
undesirable temperature fluctuations. A fixed bed MTG process is
typically run as an adiabatic process, with a significant
temperature increase across the catalyst bed because of the
exothermic nature of the methanol conversion reaction. Fluctuations
in reactor temperature profiles require significant light gas
recycle or internal cooling coils to control reactor outlet
temperature. Light gas recycle is typically used, but requires
significant capital investment in the form of high capacity
compressors and heat exchanger systems.
[0007] Thus, there is still a need for methods for converting
oxygenate-containing feedstocks, e.g., methanol, that address one
or more of these deficiencies.
SUMMARY OF INVENTION
[0008] Aspects of the invention are based in part on the discovery
that a moving bed reactor may be used in methanol conversion
despite the lack of coking. Aspects of the invention additionally
or alternatively are based at least in part on the discovery that,
over the catalyst life cycle, a moving bed reactor process
approximates the end of cycle performance of a fixed bed reactor,
where product distribution is desirable. The invention is also
based in part on the observation that a moving bed process provides
higher feedstock utilization over the catalyst lifetime. The
invention is also based in part on the understanding that the use
of a moving bed reactor for a highly exothermic reaction can reduce
process variability and costly gas recycle, particularly when
coupled with liquid quenching of the product at one or more stages
of the reaction.
[0009] Thus, in one aspect, embodiments of the invention provide a
method for organic compound conversion, comprising: a) providing a
first mixture comprising .gtoreq.10.0 wt % of at least one
oxygenate, based on the weight of the first mixture; b) contacting
said first mixture in at least a first moving bed reactor with a
catalyst under conditions effective to covert at least a portion of
the first mixture to a product stream comprising water, hydrogen,
and one or more hydrocarbons; and c) separating from said product
stream (i) at least one light stream and ii) at least one heavy
stream, wherein the method is characterized by a recycle ratio of
.ltoreq.5.0.
[0010] In another aspect, embodiments of the invention provide a
method for organic compound conversion, comprising: a) providing a
first mixture comprising .gtoreq.10.0 wt % of at least one
oxygenate, based on the weight of the first mixture; b) contacting
said first mixture in a first moving bed reactor with a first
catalyst under conditions effective to covert at least a portion of
the first mixture to a first product stream comprising a first
amount of one or more hydrocarbons; c) contacting said first
product stream in a second moving bed reactor with a second
catalyst under conditions effective to covert at least a portion of
the first product stream to a second product stream comprising
water, hydrogen, and a second amount of one or more hydrocarbons;
and d) separating from said second product stream (i) at least one
light stream, and (ii) at least one heavy stream, wherein the
method is characterized by a recycle ratio of .ltoreq.5.0.
[0011] In yet another aspect, embodiments of the invention provide
methods for organic compound conversion, comprising: a) providing a
first mixture comprising .gtoreq.10.0 wt % of at least one
oxygenate, based on the weight of the first mixture; b) contacting
said first mixture in a first moving bed reactor with a first
catalyst under conditions effective to covert at least a portion of
the first mixture to a first product stream comprising water,
hydrogen, and a first amount of one or more hydrocarbons; c)
contacting said first product stream in a second moving bed reactor
with a second catalyst under conditions effective to covert at
least a portion of the first product stream to a second product
stream comprising water, hydrogen, and a second amount of one or
more hydrocarbons; d) contacting said second product stream in a
third moving bed reactor with a third catalyst under conditions
effective to covert at least a portion of the second product stream
to a third product stream comprising water, hydrogen, and a third
amount of one or more hydrocarbons; and e) separating from said
third product stream (i) at least one hydrocarbon-enriched
hydrocarbon stream, and (ii) at least one heavy stream, wherein the
method is characterized by a recycle ratio of .ltoreq.5.0.
[0012] Particular embodiments benefit from the combination of a
moving bed reactor and ability to provide a liquid quench of the
reactor effluent, particularly an interstage liquid quench where
two or more reactors, or reaction zones, are employed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 schematically illustrates a method of organic
compound conversion according to an embodiment of the
invention.
[0014] FIG. 2 schematically illustrates a method of organic
compound conversion according to another embodiment of the
invention.
[0015] FIG. 3 schematically illustrates a method of organic
compound conversion according to yet another embodiment of the
invention.
[0016] FIG. 4 compares reactor bed temperature as a function of bed
position for exemplary fixed bed and moving bed reactor
configurations.
[0017] FIG. 5 compares gasoline fraction product yield as a
function of bed position for exemplary fixed bed and moving bed
reactor configurations.
[0018] FIG. 6 compares relative catalyst activity as a function of
bed position for exemplary fixed bed and moving bed reactor
configurations.
[0019] FIG. 7 compares oxygenate utilization relative to catalyst
age for exemplary fixed bed and moving bed reactor
configurations.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0020] The present process is useful for the conversion a first
mixture comprising oxygen-containing organic compounds (i.e.,
"oxygenates") into hydrocarbon products where the conversion is
carried out by an exothermic catalytic reaction. In particular the
catalytic conversion is conducted in a moving bed reactor, the use
of which enables a process having a lower recycle ratio than
conventional processes.
[0021] For the purposes of this invention and the claims thereto,
the numbering scheme for the Periodic Table Groups is used as
described in Chemical and Engineering News, 63(5), pg. 27
(1985).
[0022] As used herein references to a "reactor" shall be understood
to include both distinct reactors as well as reaction zones within
a single reactor apparatus. In other words and as is common, a
single reactor may have multiple reaction zones. Where the
description refers to a first and second reactor, the person of
ordinary skill in the art will readily recognize such reference
includes a single reactor having first and second reaction zones.
Likewise, a first reactor effluent and a second reactor effluent
will be recognized to include the effluent from the first reaction
zone and the second reaction zone of a single reactor,
respectively.
[0023] As used herein, the phrases "light stream" and "heavy
stream" are relative. A "light stream" will generally have a mean
boiling point lower than the mean boiling point of a "heavy
stream." Without limiting the foregoing definition, in some
embodiments, the light stream may comprise a majority of molecules
having 10 or fewer carbon atoms, e.g., 9 or fewer, 8 or fewer, 7 or
fewer, 6 or fewer, 5 or fewer, 4 or fewer, 3, or fewer, 2 or fewer,
1 or fewer, or no carbon atoms.
[0024] As used herein the phrase "at least a portion of" means
.gtoreq.0 to 100.0 wt % of the process stream or composition to
which the phrase refers. The phrase "at least a portion of" refers
to an amount .ltoreq.about 1.0 wt %, .ltoreq.about 2.0 wt %,
.ltoreq.about 5.0 wt %, .ltoreq.about 10.0 wt %, .ltoreq.about 20.0
wt %, .ltoreq.about 25.0 wt %, .ltoreq.about 30.0 wt %,
.ltoreq.about 40.0 wt %, .ltoreq.about 50.0 wt %, .ltoreq.about
60.0 wt %, .ltoreq.about 70.0 wt %, .ltoreq.about 75.0 wt %,
.ltoreq.about 80.0 wt %, .ltoreq.about 90.0 wt %, .ltoreq.about
95.0 wt %, .ltoreq.about 98.0 wt %, .ltoreq.about 99.0 wt %, or
.ltoreq.about 100.0 wt %. Additionally or alternatively, the phrase
"at least a portion of" refers to an amount .gtoreq.about 1.0 wt %,
.gtoreq.about 2.0 wt %, .gtoreq.about 5.0 wt %, .gtoreq.about 10.0
wt %, .gtoreq.about 20.0 wt %, .gtoreq.about 25.0 wt %,
.gtoreq.about 30.0 wt %, .gtoreq.about 40.0 wt %, .gtoreq.about
50.0 wt %, .gtoreq.about 60.0 wt %, .gtoreq.about 70.0 wt %,
.gtoreq.about 75.0 wt %, .gtoreq.about 80.0 wt %, .gtoreq.about
90.0 wt %, .gtoreq.about 95.0 wt %, .gtoreq.about 98.0 wt %,
.gtoreq.about 99.0 wt %, or 100.0 wt %.
[0025] Ranges expressly disclosed include combinations of any of
the above-enumerated values; e.g., 10.0 to 100.0 wt %, 10.0 to 98.0
wt %, 2.0 to 10.0, 40.0 to 60.0 wt %, etc.
[0026] As used herein the term "first mixture" means a
hydrocarbon-containing composition including one or more
oxygenates. Typically, the first mixture comprises .gtoreq.10.0 wt
% of at least one oxygenate, based on the weight of the first
mixture. Thus, the amount of oxygenate(s) in the first mixture may
be .gtoreq.10.0 wt %, .gtoreq.about 12.5 wt %, .gtoreq.about 15.0
wt %, .gtoreq.about 20.0 wt %, .gtoreq.about 25.0 wt %,
.gtoreq.about 30.0 wt %, .gtoreq.about 35.0 wt %, .gtoreq.about
40.0 wt %, .gtoreq.about 45.0 wt %, .gtoreq.about 50.0 wt %,
.gtoreq.about 55.0 wt %, .gtoreq.about 60.0 wt %, .gtoreq.about
65.0 wt %, .gtoreq.about 70.0 wt %, .gtoreq.about 75.0 wt %,
.gtoreq.about 80.0 wt %, .gtoreq.about 85.0 wt %, .gtoreq.about
90.0 wt %, .gtoreq.about 95.0 wt %, .gtoreq.about 99.0 wt %,
.gtoreq.about 99.5 wt %, or about 100.0 wt %. Additionally or
alternatively, the amount of oxygenate in the first mixture may be
.ltoreq.about 12.5 wt %, .ltoreq.about 15.0 wt %, .ltoreq.about
20.0 wt %, .ltoreq.about 25.0 wt %, .ltoreq.about 30.0 wt %,
.ltoreq.about 35.0 wt %, .ltoreq.about 40.0 wt %, .ltoreq.about
45.0 wt %, .ltoreq.about 50.0 wt %, .ltoreq.about 55.0 wt %,
.ltoreq.about 60.0 wt %, .ltoreq.about 65.0 wt %, .ltoreq.about
70.0 wt %, .ltoreq.about 75.0 wt %, .ltoreq.about 80.0 wt %,
.ltoreq.about 85.0 wt %, .ltoreq.about 90.0 wt %, .ltoreq.about
95.0 wt %, .ltoreq.about 99.0 wt %, .ltoreq.about 99.5 wt %, or
.ltoreq.about 100.0 wt %. Ranges expressly disclosed include
combinations of any of the above-enumerated values; e.g.,
.gtoreq.10.0 to about 100.0 wt %, about 12.5 to about 99.5 wt %,
about 20.0 to about 90.0, about 50.0 to about 99.0 wt %, etc.
[0027] As used herein the term "oxygenate," oxygenate composition,"
and the like refer to oxygen-containing compounds having 1 to about
50 carbon atoms, 1 to about 20 carbon atoms, 1 to about 10 carbon
atoms, or 1 to about 4 carbon atoms. Exemplary oxygenates include
alcohols, ethers, carbonyl compounds, e.g., aldehydes, ketones and
carboxylic acids, and mixtures thereof. Particular oxygenates
methanol, ethanol, dimethyl ether, diethyl ether, methylethyl
ether, di-isopropyl ether, dimethyl carbonate, dimethyl ketone,
formaldehyde, and acetic acid.
[0028] In particular embodiments, the oxygenate comprises one or
more alcohols, preferably alcohols having 1 to about 20 carbon
atoms, 1 to about 10 carbon atoms, or 1 to about 4 carbon atoms.
The alcohols useful as first mixtures may linear or branched,
substituted or unsubstituted aliphatic alcohols and their
unsaturated counterparts. Non-limiting examples of such alcohols
include methanol, ethanol, propanols (e.g., n-propanol,
isopropanol), butanols (e.g., n-butanol, sec-butanol, tert-butyl
alcohol), pentanols, hexanols, etc., and mixtures thereof. In any
embodiment described herein, the first mixture may be one or more
of methanol, and/or ethanol, particularly methanol. In any
embodiment, the first mixture may be methanol and dimethyl
ether.
[0029] The oxygenate, particularly where the oxygenate comprises an
alcohol (e.g., methanol), may optionally be subjected to
dehydration, e.g., catalytic dehydration over e.g.,
.gamma.-alumina. Further optionally, at least a portion of any
methanol and/or water remaining in the first mixture after
catalytic dehydration may be separated from the first mixture. If
desired, such catalytic dehydration may be used to reduce the water
content of reactor effluent before it enters a subsequent reactor
or reaction zone, e.g., second and/or third reactors as discussed
below.
[0030] In any embodiment, one or more other compounds may be
present in first mixture. Some common or useful such compounds have
1 to about 50 carbon atoms, e.g., 1 to about 20 carbon atoms, 1 to
about 10 carbon atoms, or 1 to about 4 carbon atoms. Typically,
although not necessarily, such compounds include one or more
heteroatoms other than oxygen Some such compounds include amines,
halides, mercaptans, sulfides, and the like. Particular such
compounds include alkyl-mercaptans (e.g., methyl mercaptan and
ethyl mercaptan), alkyl-sulfides (e.g., methyl sulfide),
alkyl-amines (e.g., methyl amine), alkyl-halides (e.g., methyl
chloride and ethyl chloride). In particular embodiments, the first
mixture includes one or more of .gtoreq.1.0 wt % acetylene,
pyrolysis oil or aromatics, particularly C.sub.6 and/or C.sub.7
aromatics. Thus, the amount of such other compounds in the first
mixture may be .ltoreq.about 2.0 wt %, .ltoreq.about 5.0 wt %,
.ltoreq.about 10.0 wt %, .ltoreq.about 15.0 wt %, .ltoreq.about
20.0 wt %, .ltoreq.about 25.0 wt %, .ltoreq.about 30.0 wt %,
.ltoreq.about 35.0 wt %, .ltoreq.about 40.0 wt %, .ltoreq.about
45.0 wt %, .ltoreq.about 50.0 wt %, .ltoreq.about 60.0 wt %,
.ltoreq.about 75.0 wt %, .ltoreq.about 90.0 wt %, or .ltoreq.about
95.0 wt %. Additionally or alternatively, the amount of such other
compounds in the first mixture may be .gtoreq.about 2.0 wt %,
.gtoreq.about 5.0 wt %, .gtoreq.about 10.0 wt %, .gtoreq.about 15.0
wt %, .gtoreq.about 20.0 wt %, .gtoreq.about 25.0 wt %,
.gtoreq.about 30.0 wt %, .gtoreq.about 35.0 wt %, .gtoreq.about
40.0 wt %, .gtoreq.about 45.0 wt %, .gtoreq.about 50.0 wt %,
.gtoreq.about 60.0 wt %, .gtoreq.about 75.0 wt %, or .gtoreq.about
90.0 wt %. Ranges expressly disclosed include combinations of any
of the above-enumerated values; e.g., 1.0 to about 10.0 wt %, about
2.0 to about 5.0 wt %, about 10.0 to about 95.0 wt %, about 15.0 to
about 90.0 wt %, about 20.0 to about 75.0 wt %, about 25.0 to about
60 wt %, about 30.0 to about 50 wt %, about 35.0 to about 45 wt %,
about 40.0 wt %, etc.
[0031] The term "catalyst" as used herein refers to a composition
of matter comprising a zeolite and optionally a Group 2-12 element
of the Periodic Table. In this sense the term comprising can also
mean that the catalyst can comprise the physical or chemical
reaction product of the zeolite another compound such as the Group
2-12 element, a filler, and/or binder. The catalyst may be combined
with a carrier to form a slurry.
[0032] The zeolite employed in the present catalyst composition
generally comprises at least one medium pore aluminosilicate
zeolite having a Constraint Index of 1-12. The Constraint Index may
be .ltoreq.about 12.0, .ltoreq.about 11.0, .ltoreq.about 10.0,
.ltoreq.about 9.0, .ltoreq.about 8.0, .ltoreq.about 7.0,
.ltoreq.about 6.0, .ltoreq.about 5.0, .ltoreq.about 4.0,
.ltoreq.about 3.0, or .ltoreq.about 2.0. Additionally or
alternatively, the Constraint Index may be about .gtoreq.about
11.0, .gtoreq.about 10.0, .gtoreq.about 9.0, .gtoreq.about 8.0,
.gtoreq.about 7.0, .gtoreq.about 6.0, .gtoreq.about 5.0,
.gtoreq.about 4.0, .gtoreq.about 3.0, .gtoreq.about 2.0, or
.gtoreq.about 1.0. In any embodiment, the Constraint Index may be
1.0 to about 10.0, 1.0 to about 8.0, 1 to about 6.0, 1 to about
5.0, 1 to about 3.0, 2.0 to about 11.0, 3.0 to 10.0, 4.0 to 9.0, or
6.0 to 9.0, etc. Constraint Index is determined as described in
U.S. Pat. No. 4,016,218, incorporated herein by reference for
details of the method.
[0033] Some useful catalysts compositions include a zeolite having
a structure wherein there is at least one 10-member ring channel
and no channel of rings having more than 10 members. Some such
molecular sieves may be referred to as having a framework type or
topology of EUO, FER, IMF, LAU, MEL, MRI, MFS, MTT, MWW, NES, PON,
SFG, STF, STI, TUN, or PUN. Particularly useful zeolites have a
BEA. MFI or MEL framework.
[0034] Non-limiting examples of zeolites useful herein include one
or a combination of SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17,
SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37,
SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, and SAPO-56.
[0035] Particular other zeolites useful in embodiments of the
invention include ZSM-5, ZSM-11; ZSM-12; ZSM-22; ZSM-23; ZSM-34,
ZSM-35; ZSM-48; ZSM-57; and ZSM-58. Other useful zeolites may
include MCM-22. PSH-3, SSZ-25, MCM-36, MCM-49 or MCM-56, with
MCM-22. In any embodiment the zeolite may be ZSM-5 or ZSM-11. ZSM-5
is described in detail in U.S. Pat. No. 3,702,886 and RE 29,948.
ZSM-11 is described in detail in U.S. Pat. No. 3,709,979. ZSM-5 is
particularly useful.
[0036] The catalyst composition can employ the zeolite in its
original crystalline form or after formulation into catalyst
particles, such as by extrusion. A process for producing zeolite
extrudates in the absence of a binder is disclosed in, for example,
U.S. Pat. No. 4,582,815, the entire contents of which are
incorporated herein by reference. Some processes utilize a
hydrothermally stabilized catalyst composition.
[0037] Hydrothermally stabilized zeolite catalyst compositions are
well-known and are typically stabilized by incorporation of a Group
15 element, particularly phosphorous. The Group 15 element can be
incorporated after formulation of the zeolite (such as by
extrusion) to form self-bound catalyst particles. Optionally, a
self-bound catalyst can be steamed after extrusion. Such
compositions are particularly useful where the reactor feed, e.g.,
first mixture provided to the first reactor, the first product
stream provided to the second reactor, and/or the second product
stream provided to the third reactor, includes a significant amount
of water, e.g., .gtoreq.5 wt % H.sub.2O. While a hydrothermally
stabilized catalyst may be used in any embodiment, such catalyst
compositions are also particularly useful where the liquid quench
medium is water.
[0038] In particular embodiments, the zeolite may be combined with
5.0 to 75.0 wt %, e.g., 10.0 to 65.0 wt %, 20.0 to 55.0 wt %, 25.0
to 45.0 wt %, or 30.0 to 40.0 wt %, of a binder. There are many
different binders that are useful in forming the catalyst
compositions used herein. Non-limiting examples of binders that are
useful alone or in combination include various types of metal
oxides, e.g., hydrated alumina, silicas, and/or other inorganic
oxide sols. One preferred alumina containing sol is aluminum
chlorhydrol. Upon heating, the inorganic oxide sol, preferably
having a low viscosity, is converted into an inorganic oxide binder
component. For example, an alumina sol will convert to an aluminum
oxide binder following heat treatment.
[0039] Aluminum chlorhydrol, a hydroxylated aluminum based sol
containing a chloride counter ion, has the general formula of
Al.sub.mO.sub.n(OH).sub.oCl.sub.p.x(H.sub.2O) wherein m is 1 to 20,
n is 1 to 8, o is 5 to 40, p is 2 to 15, and x is 0 to 30. In one
embodiment, the binder is
Al.sub.13O.sub.4(OH).sub.24Cl.sub.7.12(H.sub.2O) as is described in
G. M. Wolterman, et al., Stud. Surf. Sci. and Catal., 76, pages 105
144 (1993), which is herein incorporated by reference. In another
embodiment, one or more binders are combined with one or more other
non-limiting examples of alumina materials such as aluminum
oxyhydroxide, boehmite, diaspore, and transitional aluminas such as
.alpha.-alumina, .beta.-alumina, .gamma.-alumina. .delta.-alumina,
.epsilon.-alumina, .kappa.-alumina, and .rho.-alumina, aluminum
trihydroxide, such as gibbsite, bayerite, nordstrandite, doyelite,
and mixtures thereof.
[0040] In some embodiments, the binder is an alumina sol,
predominantly comprising aluminum oxide, optionally including some
silicon. In yet another embodiment, the binder is peptized alumina
made by treating an alumina hydrate, such as pseudobohemite, with
an acid, preferably an acid that does not contain a halogen, to
prepare a sol or aluminum ion solution. Non-limiting examples of
commercially available colloidal alumina sols include Nalco 8676
available from Nalco Chemical Co., Naperville, Ill., and Nyacol
AL20DW available from Nyacol Nano Technologies, Inc., Ashland,
Mass.
[0041] A process for converting an oxygenate-containing first
mixture to a hydrocarbon stream containing aromatic molecules in
the present of the catalyst described above will now be described.
FIG. 1 schematically illustrates a process 100, an
oxygenated-containing feed is provided via line 102 optional
dehydration unit 104 or to moving bed reactor 106. Moving bed
reactor 106 may be any reactor suitable for converting an
oxygenate-containing first mixture to an aromatics-containing
hydrocarbon effluent. One such moving bed reactor is described in
Industrial and Engineering Chemistry, "Thermofor Catalytic Cracking
Unit," vol. 39, no. 12, pp. 1685-1690, incorporated herein by
reference in its entirety. In any embodiment, the reactor 106 may
include one or more moving bed reactor having the catalyst therein.
Where reactor 106 includes more than one reactor, the reactors may
be arranged in any suitable configuration, e.g., in series,
parallel, or series-parallel.
[0042] Moving bed reactor 106 may be operated with a catalyst and
under conditions to produce a product stream comprising water, one
or more hydrocarbons, and hydrogen. In particular embodiments, the
reactor 106 is operated at a weight hourly space velocity (WHSV, g
oxygenate/g catalyst/hour) in the range of from 0.50 to 12.0
hr.sup.-1. The WHSV may be 0.5 to 11.0 hr.sup.-1, 0.5 to 10.0
hr.sup.-1, 0.5 to 9.0 hr.sup.-1, 0.5 to 7.0 hr.sup.-1, 0.5 to 6.0
hr.sup.-1, 0.5 to 5.0 hr.sup.-1, 0.5 to 4.0 hr.sup.-1, 0.5 to 3.0
hr.sup.-1, 0.5 to 2.0 hr.sup.-1, 0.5 to 1.0 hr.sup.-1, 1.0 to 11.0
hr.sup.-1, 1.0 to 10.0 hr.sup.-1, 1.0 to 9.0 hr.sup.-1, 1.0 to 7.0
hr.sup.-1, 1.0 to 6.0 hr.sup.-1, 1.0 to 5.0 hr.sup.-1, 1.0 to 4.0
hr.sup.-1, 1.0 to 3.0 hr.sup.-1, 1.0 to 2.0 hr.sup.-1, 2.0 to 11.0
hr.sup.-1, 2.0 to 10.0 hr.sup.-1, 2.0 to 9.0 hr.sup.-1, 2.0 to 7.0
hr.sup.-1, 2.0 to 6.0 hr.sup.-1, 2.0 to 5.0 hr.sup.-1, 2.0 to 4.0
hr.sup.-1, 2.0 to 3.0 hr.sup.-1, 3.0 to 11.0 hr.sup.-1, 3.0 to 10.0
hr.sup.-1, 3.0 to 9.0 hr.sup.-1, 3.0 to 7.0 hr.sup.-1, 3.0 to 6.0
hr.sup.-1, 3.0 to 5.0 hr.sup.-1, 3.0 to 4.0 hr.sup.-1, 4.0 to 11.0
hr.sup.-1, 4.0 to 10.0 hr.sup.-1, 4.0 to 9.0 hr.sup.-1, 4.0 to 7.0
hr.sup.-1, 4.0 to 6.0 hr.sup.-1, or about 0.50 hr.sup.-1.
[0043] Additionally or alternatively, the first mixture comprising
the oxygenate is exposed in moving bed reactor 106 to a temperature
.gtoreq.about 400.degree. C. and a pressure .gtoreq.1 bar absolute.
In any embodiment, the temperature may be .gtoreq.about
425.0.degree. C., .gtoreq.about 450.0.degree. C., .gtoreq.about
475.0.degree. C., .gtoreq.about 500.0.degree. C., .gtoreq.about
525.0.degree. C., .gtoreq.about 550.0.degree. C., .gtoreq.about
600.degree. C., .gtoreq.about 650.degree. C., or .gtoreq.about
700.degree. C. Additionally or alternatively, the temperature of
reactor 106 may be .ltoreq.about 425.0.degree. C., .ltoreq.about
450.0.degree. C., .ltoreq.about 475.0.degree. C., .ltoreq.about
500.0.degree. C., .ltoreq.about 525.0.degree. C., .ltoreq.about
550.0.degree. C., .ltoreq.about 600.degree. C., .ltoreq.about
650.degree. C., or .ltoreq.about 700.degree. C. Ranges of
temperatures expressly disclosed include combinations of any of the
above-enumerated values. Such temperature ranges may be used in
combination with a reactor pressure of about 2.0 to about 500.0 bar
absolute. In particular embodiments, the pressure may be
.ltoreq.about 10.0 bar absolute, .ltoreq.about 50 bar absolute,
.ltoreq.about 75.0 bar absolute, .ltoreq.about 100.0 bar absolute,
.ltoreq.about 125.0 bar absolute, .ltoreq.about 150.0 bar absolute,
.ltoreq.about 175.0 bar absolute, .ltoreq.about 200.0 bar absolute,
.ltoreq.about 250.0 bar absolute, .ltoreq.about 300.0 bar absolute,
.ltoreq.about 350.0 bar absolute, .ltoreq.about 400 bar absolute,
or .ltoreq.about 450 bar absolute. Additionally or alternatively,
the pressure may be .gtoreq.about 5.0 bar absolute, .gtoreq.about
10.0 bar absolute, .gtoreq.about 50 bar absolute, .gtoreq.about
75.0 bar absolute, .gtoreq.about 100.0 bar absolute, .gtoreq.about
125.0 bar absolute, .gtoreq.about 150.0 bar absolute, .gtoreq.about
175.0 bar absolute, .gtoreq.about 200.0 bar absolute, .gtoreq.about
250.0 bar absolute, 300.0 bar absolute. Ranges and combinations of
temperatures and pressures expressly disclosed include combinations
of any of the above-enumerated values.
[0044] The product stream from reactor 106 is provided via a line
108 to first separation unit 110 for separation into (i) at least
one aromatic-rich hydrocarbon stream 112, and (ii) at least one
heavy stream 112. First separation unit 110 may be any suitable
separation means, e.g., distillation tower, simulated moving-bed
separation unit, high pressure separator, low pressure separator,
flash drum, etc.
[0045] In any embodiment, the recycle ratio may be .ltoreq.5.0,
e.g. .ltoreq.about 4.0, .ltoreq.about 3.0, .ltoreq.about 2.0,
.ltoreq.about 1.0, .ltoreq.about 0.5. Additionally or
alternatively, the recycle ratio may be 0, .ltoreq.about 0.25,
.ltoreq.about 0.5, .ltoreq.about 1.0, .ltoreq.about 2.0,
.ltoreq.about 3.0, .ltoreq.about 4.0, e.g., 0 to about 5.0, 0 to
about 4.0, 0 to about 3.0, 0 to about 2.0, 0 to about 1.0, 0 to
about 0.5, or 0 to about 0.25. As used herein the term "recycle
ratio" refers to the ratio of the number of moles of gas recycled
to the reactor to the total number of moles of oxygenate provided
to the reactor. For example, the gas recycled to the reactor may be
a stream comprising molecules having 5 or fewer carbon atoms. Due
to the highly exothermic nature of the conversion process, such
recycle ratios are not sufficient to control reactor temperature
within acceptable limits for fixed or fluid bed reactors. The
reduction in recycle ratio reduces or eliminates
capitally-intensive equipment, e.g., compressors, heat exchangers,
etc., needed to implement such higher recycle ratios.
[0046] Typically, light stream 112 can be sent for further
processing, e.g., to recover the desired aromatic or olefinic
molecules therein. In any embodiment, however, at least a portion
of hydrocarbon-enriched light stream 112 may optionally be recycled
to reactor 106 via recycle line 116, e.g., by combination directly
or indirectly with the first mixture in line 102. In particular
embodiments, .gtoreq.50.0 wt %, 50.0 to 100 wt %, 60.0 to 95.0 wt
%, 70.0 to 90.0 wt %, 80.0 to 85.0 wt %, of the first mixture's
aromatics can be the recycled aromatics, weight percents being
based on the total amount of aromatics in the first mixture.
Additionally or alternatively, at least a portion of light stream
112 may be provided via a line 118 to line 108 exiting reactor 106
to quench the product stream. Additionally or alternatively, a
liquid quench medium can be provided via line 120. Liquid quench
medium provided via line 120 may be any liquid suitable for
quenching the reaction, e.g., at least a portion of the light
stream, at least a portion of the heavy stream, one or more
oxygenates, and/or water.
[0047] Additionally or alternatively, at least a portion of heavy
stream 114 exiting first separation unit 110 may be recycled to
reactor 106, e.g., by combination, directly or indirectly, with
line 102 via line 116. While processes having high conversion may
not necessarily benefit from doing so, any oxygenates remaining in
heavy stream 114 may be recovered therefrom. At least a portion of
the recovered oxygenates may thereafter be provided to reactor
106.
[0048] With continuing reference to FIG. 1, FIG. 2 schematically
depicts a process 200 according to particular embodiments. The
first product stream 108 exiting moving bed reactor 106 can be
provided to a second moving bed reactor 202. Moving bed reactor 202
may be of any suitable design, e.g., as described for moving bed
reactor 106 and may be operated under conditions and provide
product characteristics as described for moving bed reactor 106.
Embodiments may also include means to transport catalyst from
reactor 106 to reactor 202.
[0049] In embodiments of the invention, first moving bed reactor
106 may be operated at a WHSV greater than or less than that of
second moving bed reactor 202. In particular embodiments, the WHSV
of the first moving bed reactor 106 can be greater than that of the
second moving bed reactor 202. Although it is not critical, in any
embodiment, the ratio of the WHSV of the second reactor 202 to the
WHSV of the first reactor 106 may be .gtoreq.about 40.0,
.gtoreq.about 35.0, .gtoreq.about 30.0, .gtoreq.about 25.0,
.gtoreq.about 20.0, .gtoreq.about 15.0, .gtoreq.about 10.0,
.gtoreq.about 5.0, .gtoreq.about 2.5, .gtoreq.about 2.0, or
.gtoreq.about 1.5. Additionally or alternatively, the ratio of the
WHSV of the second reactor 202 to the WHSV of the first reactor 106
may be .ltoreq.about 1.1, .ltoreq.about 1.5, .ltoreq.about 2.0,
.ltoreq.about 2.5, .ltoreq.about 5.0, .ltoreq.about 10.0,
.ltoreq.about 15.0, .ltoreq.about 20.0, .ltoreq.about 25.0,
.ltoreq.about 30.0, .ltoreq.about 35.0, .ltoreq.about 40.0.
Exemplary ranges of the ratio of the WHSV of the first reactor 106
to the WHSV of the second reactor 202 include about 1.1 to about
40.0, about 1.5 to about 35.0, about 2.0 to about 30.0, about 2.5
to about 25.0, about 5.0 to about 20.0, about 10.0 to about 15.0,
about 30.0 to about 40.0, about 25.0 to about 40.0, about 20.0 to
about 40.0, about 15.0 to about 40.0, about 10.0 to about 40.0,
about 5.0 to about 40.0, about 2.5 to about 40.0, about 2.0 to
about 40.0, about 1.5 to about 40.0, about 25.0 to about 30.0,
about 20.0 to about 30.0, about 15.0 to about 30.0, about 10.0 to
about 30.0, about 5.0 to about 30.0, about 2.5 to about 30.0, about
2.0 to about 30.0, about 1.5 to about 30.0, about 1.1 to about
30.0, etc.
[0050] The second product stream may be directed from second moving
bed reactor 202 via line 204 to separation unit 110. As described
with respect to FIG. 1, separation unit 110 may separate the second
product stream into the at least one hydrocarbon-enriched stream
112, and the at least one heavy stream 114. In some embodiments
including the second moving bed reactor 202, at least a portion of
the stream 112 may be recycled to the first moving bed reactor 106
via line 116 or provided as a quench via line 118. Additionally or
alternatively, at least a portion of the stream 112 may be combined
with the second product stream 204, e.g., via line 206 to quench
the second product stream 204. Optionally, a liquid quench medium
may be supplied to the second product stream 204 via line 208. The
liquid quench medium supplied via line 208 may be the same or
different than that provided by line 120.
[0051] As described with respect to FIG. 1, at least a portion of
heavy stream 114 from embodiments including the second reactor 202
may optionally be recycled to reactor 106 via recycle line 116,
e.g., by combination directly or indirectly with the first mixture
in line 102. Additionally or alternatively as described with
respect to FIG. 1, at least a portion of heavy stream 114 may be
provided via a line 118 to line 108 exiting reactor 106 to quench
the first product stream. Additionally or alternatively, at least a
portion of the stream 114 may be combined with the second product
stream 204, e.g., via line 206 to quench the second product stream
204.
[0052] With continuing reference to FIGS. 1 and 2, FIG. 3
schematically depicts a process 300 according to particular
embodiments wherein the second product stream 204 exiting moving
bed reactor 202 can be provided to a third moving bed reactor 302.
Moving bed reactor 302 may be of any suitable design, e.g., as
described for moving bed reactors 106 and 202 and may be operated
under conditions and provide product characteristics as described
for moving bed reactors 106 and 202. Embodiments may also include
means to transport catalyst from reactors 106 and/or reactor 202 to
reactor 302.
[0053] In embodiments of the invention, second moving bed reactor
202 may be operated at a WHSV greater than or less than that of
third moving bed reactor 302. In particular embodiments, the WHSV
of the second moving bed reactor 202 is greater than that of the
third moving bed reactor 302. Although it is not critical, in any
embodiment, the ratio of the WHSV of the second reactor 202 to the
WHSV of the third reactor 302 may be .ltoreq.about 40.0,
.ltoreq.about 35.0, .ltoreq.about 30.0, .ltoreq.about 25.0,
.ltoreq.about 20.0, .ltoreq.about 15.0, .ltoreq.about 10.0,
.ltoreq.about 5.0, .ltoreq.about 2.5, .ltoreq.about 2.0, or
.ltoreq.about 1.5. Additionally or alternatively, the ratio of the
WHSV of the second reactor 202 to the WHSV of the third reactor 302
may be .gtoreq.about 1.1, .gtoreq.about 1.5, .gtoreq.about 2.0,
.gtoreq.about 2.5, .gtoreq.about 5.0, .gtoreq.about 10.0,
.gtoreq.about 15.0, .gtoreq.about 20.0, .gtoreq.about 25.0,
.gtoreq.about 30.0, .gtoreq.about 35.0, .gtoreq.about 40.0.
Exemplary ranges of the ratio of the WHSV of the second reactor 202
to the WHSV of the third reactor 302 include about 1.1 to about
40.0, about 1.5 to about 35.0, about 2.0 to about 30.0, about 2.5
to about 25.0, about 5.0 to about 20.0, about 10.0 to about 15.0,
about 30.0 to about 40.0, about 25.0 to about 40.0, about 20.0 to
about 40.0, about 15.0 to about 40.0, about 10.0 to about 40.0,
about 5.0 to about 40.0, about 2.5 to about 40.0, about 2.0 to
about 40.0, about 1.5 to about 40.0, about 25.0 to about 30.0,
about 20.0 to about 30.0, about 15.0 to about 30.0, about 10.0 to
about 30.0, about 5.0 to about 30.0, about 2.5 to about 30.0, about
2.0 to about 30.0, about 1.5 to about 30.0, about 1.1 to about
30.0, etc.
[0054] The third product stream may be directed from third moving
bed reactor 302 via line 304 to separation unit 110. As described
with respect to FIG. 1, separation unit 110 may separate the third
product stream the at least one light stream 112, and the at least
one heavy stream 114. As described with respect to FIGS. 1 and 2,
at least a portion of light stream from embodiments including the
third reactor 302 may optionally be recycled to reactor 106 via
recycle line 116, e.g., by combination directly or indirectly with
the first mixture in line 102. Additionally or alternatively as
described with respect to FIGS. 1 and 2, at least a portion of
light stream 112 may be provided via a line 118 to line 108 exiting
reactor 106 to quench the first product stream and or the to quench
the second product stream via line 206. Additionally or
alternatively, at least a portion of the light stream 112 may be
combined with the third product stream 304, e.g., via line 306 to
quench the third product stream 304. Likewise, at least a portion
of heavy stream 114 may be combined with the first mixture in line
102, e.g., via line 116; provided via line 118 to quench the first
product stream exiting reactor 106; combined with the second
product stream 204, e.g., via line 206 to quench the second product
stream 204; and/or provided via line 306 to quench the third
product stream 304. Product stream 304, optionally, may also be
quenched by an external liquid quench medium via line 308. The
liquid quench medium supplied via line 308 may be the same or
different than that provided by line 120 and/or 208.
Product Compositions
[0055] The processes described herein may be used to manufacture a
variety of hydrocarbon compositions from the oxygenate-containing
first mixture. For example, product stream exiting the first
reactor, second and/or third reactors may comprise one or more
olefins, typically having from 2 to 30 carbon atoms, 2 to 8 carbon
atoms, 2 to 6 carbon atoms, or 2 to 4 carbons atoms, e.g.,
ethylene, propylene, butene-1, pentene-1,4-methyl-pentene-1,
hexene-1, octene-1, and decene-1, preferably ethylene, propylene,
butene-1, pentene-1,4-methyl-pentene-1, hexene-1, octene-1, and
isomers thereof. Other non-limiting examples of olefin monomer(s)
can include unsaturated monomers, diolefins having 4 to 18 carbon
atoms, conjugated or nonconjugated dienes, polyenes, vinyl
monomers, and cyclic olefins.
[0056] Additionally or alternatively, the product stream exiting
the first, second and/or third reactor may comprise .gtoreq.about
30.0 wt % of paraffinic molecules, e.g., n-, iso-, and
cyclo-paraffins, based on the weight of hydrocarbons in the product
stream. In particular embodiments, the amount of paraffinic
molecules in the hydrocarbon may be about 30.0 to about 100.0 wt %,
about 40.0 to about 100.0 wt %, about 50.0 to about 100.0 wt %,
about 60.0 to about 100 wt %, about 70.0 to about 100.0 wt %, about
80.0 to about 100.0 wt %, about 90.0 to about 100.0 wt %, about
95.0 to about 100 wt %, about 30.0 to about 95.0 wt %, about 40.0
to about 95.0 wt %, about 50.0 to about 95.0 wt %, about 60.0 to
about 95 wt %, about 70.0 to about 95.0 wt %, about 80.0 to about
95.0 wt %, about 90.0 to about 95.0 wt %, about 30.0 to about 90.0
wt %, about 40.0 to about 90.0 wt %, about 50.0 to about 90.0 wt %,
about 60.0 to about 90 wt %, about 70.0 to about 90.0 wt %, about
80.0 to about 90.0 wt %, about 30.0 to about 80.0 wt %, about 40.0
to about 80.0 wt %, about 50.0 to about 80.0 wt %, about 60.0 to
about 80 wt %, about 70.0 to about 80.0 wt %, about 30.0 to about
70.0 wt %, about 40.0 to about 70.0 wt %, about 50.0 to about 70.0
wt %, about 60.0 to about 70.0 wt %, about 30.0 to about 60.0 wt %,
about 40.0 to about 60.0 wt %, about 50.0 wt %, about 30.0 to about
40.0 wt %, about 30.0 to about 50.0 wt %, or about 40.0 to about
50.0 wt %. In some embodiments the product stream may comprise
molecules having about 8 to 20 carbon atoms, particularly from 10
to about 15 carbon atoms. Such compositions may be useful in diesel
fuel compositions.
[0057] Additionally or alternatively, the product stream exiting
the first, second and/or third reactors may comprise .gtoreq.about
30.0 wt % of aromatics, based on the weight of said hydrocarbons in
the product stream. In particular embodiments, the amount of
aromatics in the hydrocarbon may be about 30.0 to about 100.0 wt %,
about 40.0 to about 100.0 wt %, about 50.0 to about 100.0 wt %,
about 60.0 to about 100 wt %, about 70.0 to about 100.0 wt %, about
80.0 to about 100.0 wt %, about 90.0 to about 100.0 wt %, about
95.0 to about 100 wt %, about 30.0 to about 95.0 wt %, about 40.0
to about 95.0 wt %, about 50.0 to about 95.0 wt %, about 60.0 to
about 95 wt %, about 70.0 to about 95.0 wt %, about 80.0 to about
95.0 wt %, about 90.0 to about 95.0 wt %, about 30.0 to about 90.0
wt %, about 40.0 to about 90.0 wt %, about 50.0 to about 90.0 wt %,
about 60.0 to about 90 wt %, about 70.0 to about 90.0 wt %, about
80.0 to about 90.0 wt %, about 30.0 to about 80.0 wt %, about 40.0
to about 80.0 wt %, about 50.0 to about 80.0 wt %, about 60.0 to
about 80 wt %, about 70.0 to about 80.0 wt %, about 30.0 to about
70.0 wt %, about 40.0 to about 70.0 wt %, about 50.0 to about 70.0
wt %, about 60.0 to about 70.0 wt %, about 30.0 to about 60.0 wt %,
about 40.0 to about 60.0 wt %, about 50.0 wt %, about 30.0 to about
40.0 wt %, about 30.0 to about 50.0 wt %, or about 40.0 to about
50.0 wt %. In some embodiments the product stream may comprise
aromatic molecules having about 5 to 20 carbon atoms, particularly
from 5 to about 12 carbon atoms, particularly 8 to about 20 carbon
atoms, particularly those having 1 to 2 aromatic rings.
[0058] In any embodiment, the aromatics comprise .gtoreq.10.0 wt %
paraxylene, based on the weight of the aromatics. Thus, the amount
of paraxylene in the aromatics of the hydrocarbon component of the
product stream may be .gtoreq.10.0 wt %, .gtoreq.about 20.0 wt %,
.gtoreq.about 30.0 wt %, .gtoreq.about 40.0 wt %, .gtoreq.about
45.0 wt %, .gtoreq.about 50.0 wt %, .gtoreq.about 55.0 wt %,
.gtoreq.about 60.0 wt %, .gtoreq.about 65.0 wt %, .gtoreq.about
70.0 wt %, .gtoreq.about 80.0 wt %, .gtoreq.about 90.0 wt %,
.gtoreq.about 95.0 wt %, or about 100.0 wt %. Additionally or
alternatively, the amount of para-xylene in the aromatics portion
of the hydrocarbon of the product stream exiting reactor 106 may be
.ltoreq.about 12.5 wt %, .ltoreq.about 20.0 wt %, .ltoreq.about
30.0 wt %, .ltoreq.about 40.0 wt %, .ltoreq.about 45.0 wt %,
.ltoreq.about 50.0 wt %, .ltoreq.about 55.0 wt %, .ltoreq.about
60.0 wt %, .ltoreq.about 65.0 wt %, .ltoreq.about 70.0 wt %,
.ltoreq.about 80.0 wt %, .ltoreq.about 90.0 wt %, .ltoreq.about
95.0 wt % or .ltoreq.about 100%. Ranges of temperatures expressly
disclosed include combinations of any of the above-enumerated
values, e.g., about 10.0 to about 95.0 wt %, about 20.0 to 80.0 wt
%, about 30.0 to about 70.0 wt %, about 40.0 to about 60.0 wt %,
about 10.0 to about 50.0 wt %, about 20.0 to about 60.0 wt %, about
30.0 to about 50.0 wt %, etc.
[0059] In any embodiment, the hydrocarbons of the product stream
comprises a relatively small amount of durene; e.g., 0 to about
30.0 wt %, 0 to about 25.0 wt %, 0 to about 20.0 wt % 0 to about
15.0 wt % 0 to about 10.0 wt %, 0.0 to about 5.0 wt %, 0 to about
2.5 wt %, 0 to about 1.0 wt %, 1.0 to about 30.0 wt %, 1.0 to about
25.0 wt %, 1.0 to about 20.0 wt %, 1.0 to about 15.0 wt %, about
1.0 to about 10.0 wt %, about 1.0 to about 5.0 wt %, about 1.0 to
about 2.5 wt %, about 2.5 to about 30.0 wt %, about 2.5 to about
25.0 wt %, about 2.5 to about 20.0 wt %, about 2.5 to about 15.0 wt
%, about 2.5 to about 10.0 wt %, about 2.5 to about 5.0 wt %, about
5.0 to about 30.0 wt %, about 5.0 to about 25.0 wt %, about 5.0 to
about 20.0 wt %, about 5.0 to about 15.0 wt %, about 5.0 to about
10.0 wt %, about 10.0 to about 30.0 wt %, about 10.0 to about 25.0
wt %, about 10.0 to about 20.0 wt %, about 10.0 to about 15.0 wt %,
about 15.0 to about 30.0 wt %, about 15.0 to about 25.0 wt %, about
15.0 to about 20.0 wt %, about 20.0 to about 30.0 wt %, about 20.0
to about 25.0 wt %, about 25.0 to about 30.0 wt %.
[0060] One of the products in the product stream exiting reactor
106 can typically include hydrogen. Preferably, hydrogen can be
present in an amount .gtoreq.0.05 wt %. Thus, the amount of
hydrogen may be .ltoreq.about 10.0 wt %, about 5.0 wt %,
.ltoreq.about 4.0 wt %, .ltoreq.about 3.0 wt %, .ltoreq.about 2.0
wt %, .ltoreq.about 1.0 wt %, .ltoreq.about 0.50 wt %,
.ltoreq.about 0.40 wt %, .ltoreq.about 0.30 wt %, .ltoreq.about
0.20 wt %, .ltoreq.about 0.10 wt %, or 0.05 wt %. Additionally or
alternatively, the amount of hydrogen can be in some embodiments
.gtoreq.about 5.0 wt %, .gtoreq.about 4.0 wt %, .gtoreq.about 3.0
wt %, .gtoreq.about 2.0 wt %, .gtoreq.about 1.0 wt %, .gtoreq.about
0.50 wt %, .gtoreq.about 0.40 wt %, .gtoreq.about 0.30 wt %,
.gtoreq.about 0.20 wt %, .gtoreq.about 0.10 wt %, or 0.05 wt %.
Ranges of hydrogen content expressly disclosed include combinations
of any of the above-enumerated values, e.g., 0.05 wt % to about 5.0
wt %, about 0.10 to about 4.0 wt %, about 0.2 to about 3.0 wt %,
about 0.4 to about 2.0 wt %, or about 0.5 to about 1.0 wt %.
[0061] In any of the embodiments described, the at least one light
stream 112 may be separated by any suitable means into a gas stream
comprising C.sub.5- hydrocarbons and hydrogen, at least a portion
of the gas stream may, but need not, be recycled if desired at an
acceptable recycle ratio, and a product-enriched stream, e.g.,
comprises .gtoreq.about 30 wt %, .gtoreq.about 35 wt %,
.gtoreq.about 40 wt %, .gtoreq.about 50 wt %, .gtoreq.about 60 wt
%, .gtoreq.about 70 wt %, .gtoreq.about 80 wt %, about .gtoreq.90
wt %, C.sub.5+ hydrocarbons, based on the weight of the
product-enriched stream. The C.sub.5- hydrocarbons comprise may
.gtoreq.about 30 wt %, .gtoreq.about 35 wt %, .gtoreq.about 40 wt
%, .gtoreq.about 50 wt %, .gtoreq.about 60 wt %, .gtoreq.about 70
wt %, .gtoreq.about 80 wt %, about .gtoreq.90 wt %, aromatic
hydrocarbons. Thus, some embodiments may be described as further
comprising separating from the at least one light stream 112 at
least one aromatic-enriched hydrocarbon stream and at least one
aromatic-depleted hydrocarbon stream.
[0062] In embodiments designed to utilize features of the invention
to produce olefins, the at least one light stream may comprise
.gtoreq.30 wt %, .gtoreq.about 35 wt %, .gtoreq.about 40 wt %,
.gtoreq.about 50 wt %, .gtoreq.about 60 wt %, .gtoreq.about 70 wt
%, .gtoreq.about 80 wt %, or .gtoreq.about 90 wt %, of one or more
olefins, based on the weight of the light stream. Thus, some
embodiments may be described as further comprising separating from
the at least one light stream at least one olefin-enriched stream
and at least one olefin-depleted stream.
[0063] Products may also comprise mixtures of the above-recited
compositions. While some specific compositions are expressly
described as being recovered from the light stream, the skilled
person will understand that product mixtures may be isolated in a
variety of ways from various separation processes and optionally be
recombined to provide a desired product mixture, e.g., jet fuel
compositions, diesel fuel compositions, gasoline fuel compositions,
etc.
ADDITIONAL EMBODIMENTS
[0064] The embodiments of the invention are illustrated in the
following additional embodiments.
Embodiment 1
[0065] A method for organic compound conversion, comprising: a)
providing a first mixture comprising .gtoreq.10.0 wt % of at least
one oxygenate, based on the weight of the first mixture; b)
contacting said first mixture in at least a first moving bed
reactor with a catalyst under conditions effective to covert at
least a portion of the first mixture to a product stream comprising
water, hydrogen, and one or more hydrocarbons; and c) separating
from said product stream (i) at least one light stream and ii) at
least one heavy stream, wherein the method is characterized by a
recycle ratio of .ltoreq.5.0.
Embodiment 2
[0066] A method for organic compound conversion, comprising: a)
providing a first mixture comprising .gtoreq.10.0 wt % of at least
one oxygenate, based on the weight of the first mixture; b)
contacting said first mixture in a first moving bed reactor with a
first catalyst under conditions effective to covert at least a
portion of the first mixture to a first product stream comprising a
first amount of one or more hydrocarbons; c) contacting said first
product stream in a second moving bed reactor with a second
catalyst under conditions effective to covert at least a portion of
the first product stream to a second product stream comprising
water, hydrogen, and a second amount of one or more hydrocarbons;
and d) separating from said second product stream (i) at least one
light stream, and (ii) at least one heavy stream, wherein the
method is characterized by a recycle ratio of .ltoreq.5.0.
Embodiment 3
[0067] A method for organic compound conversion, comprising: a)
providing a first mixture comprising .gtoreq.10.0 wt % of at least
one oxygenate, based on the weight of the first mixture; b)
contacting said first mixture in a first moving bed reactor with a
first catalyst under conditions effective to covert at least a
portion of the first mixture to a first product stream comprising
water, hydrogen, and a first amount of one or more hydrocarbons; c)
contacting said first product stream in a second moving bed reactor
with a second catalyst under conditions effective to covert at
least a portion of the first product stream to a second product
stream comprising water, hydrogen, and a second amount of one or
more hydrocarbons; d) contacting said second product stream in a
third moving bed reactor with a third catalyst under conditions
effective to covert at least a portion of the second product stream
to a third product stream comprising water, hydrogen, and a third
amount of one or more hydrocarbons; and e) separating from said
third product stream (i) at least one hydrocarbon-enriched
hydrocarbon stream, and (ii) at least one heavy stream, wherein the
method is characterized by a recycle ratio of .ltoreq.5.0.
Embodiment 4
[0068] The method of any of the previous embodiments, further
comprising contacting the first, second, and/or third product
streams with a liquid phase quench medium.
Embodiment 5
[0069] The method of any of the previous embodiments, wherein one
or more of the first, second and/or third catalysts comprises a
phosphorous-stabilized catalyst.
Embodiment 6
[0070] The method of any of the previous embodiments, wherein the
first mixture, the first product stream, and or the second product
stream comprises .gtoreq.about 5 wt % H.sub.2O and the catalyst
comprises a phosphorous-stabilized catalyst.
Embodiment 7
[0071] The method of any of the previous embodiments, further
comprising separating from the at least one light stream a gas
stream comprising C.sub.5- hydrocarbons and hydrogen and a
product-enriched stream.
Embodiment 8
[0072] The method of any of the previous embodiments, wherein the
at least one light stream comprises .gtoreq.30 wt %, .gtoreq.about
35 wt %, .gtoreq.about 40 wt %, .gtoreq.about 50 wt %,
.gtoreq.about 60 wt %, .gtoreq.about 70 wt %, .gtoreq.about 80 wt
%, about .gtoreq.90 wt %, C.sub.5+ hydrocarbons, based on the
weight of the light stream.
Embodiment 9
[0073] The method of embodiment 8, wherein the C.sub.5+,
hydrocarbons comprise .gtoreq.about 30 wt %, .gtoreq.about 35 wt %,
.gtoreq.about 40 wt %, .gtoreq.about 50 wt %, .gtoreq.about 60 wt
%, .gtoreq.about 70 wt %, .gtoreq.about 80 wt %, about .gtoreq.90
wt % aromatic hydrocarbons, based on the weight of the C.sub.5+
hydrocarbons.
Embodiment 10
[0074] The method of embodiment 9, further comprising separating
from the at least one light stream at least one aromatic-enriched
hydrocarbon stream and at least one aromatic-depleted hydrocarbon
stream.
Embodiment 11
[0075] The method of any of embodiments 1-7, wherein the at least
one light stream comprises .gtoreq.30 wt %, .gtoreq.about 35 wt %,
.gtoreq.about 40 wt %, .gtoreq.about 50 wt %, .gtoreq.about 60 wt
%, .gtoreq.about 70 wt %, .gtoreq.about 80 wt %, about .gtoreq.90
wt %, of one or more olefins, based on the weight of the at least
one light stream.
Embodiment 12
[0076] The method of embodiment 11, further comprising separating
from the at least one light stream at least one olefin-enriched
hydrocarbon stream and at least one olefin-depleted hydrocarbon
stream.
Embodiment 13
[0077] The method of any of the previous embodiments, wherein the
recycle ratio is .ltoreq.about 4.0, .ltoreq.about 3.0,
.ltoreq.about 2.0, .ltoreq.about 1.0, .ltoreq.about 0.5,
.ltoreq.about 0.25, about 0.
Embodiment 14
[0078] The method of any of the previous embodiments, wherein a
second moving bed reactor is in fluid communication with the first
moving bed reactor, preferably in direct serial fluid communication
with the first moving bed reactor.
Embodiment 15
[0079] The method of embodiment 14, wherein a space-time velocity
of the at least one oxygenate in the first moving bed reactor is
greater than a space time velocity of the at least one oxygenate in
the second moving bed reactor.
Embodiment 16
[0080] The method of any of the previous embodiments, wherein a
third moving bed reactor is in fluid communication with the second
moving bed reactor, preferably in direct serial fluid communication
with the second moving bed reactor.
Embodiment 17
[0081] The method of embodiments 16, wherein a space-time velocity
of the at least one oxygenate in the second moving bed reactor is
greater than a space time velocity of the third moving bed
reactor.
Embodiment 18
[0082] The method of any of embodiments 2-17, wherein the first and
second catalysts are the same or different.
Embodiment 19
[0083] The method of any of embodiments 3-18, wherein the first and
third catalysts are the same or different.
Embodiment 20
[0084] The method of any of embodiments 3-19, wherein the second
and third catalyst are the same or different.
Embodiment 21
[0085] The method of any of embodiments 2-20, wherein the second
amount of one or more hydrocarbons is greater than the first amount
of one or more hydrocarbons.
Embodiment 22
[0086] The method of any of embodiments 3-21, wherein the third
amount of one or more hydrocarbons is greater than the first and/or
second amount of one or more hydrocarbons.
Embodiment 23
[0087] The method of any of the previous embodiments, where one or
more of the catalyst compositions comprises a hydrothermally
stabilized zeolite catalyst composition, e.g.,
phosphorous-stabilized catalyst composition, and the liquid quench
medium provided to one or more of the first, second, and/or third
reactors comprises water.
EXAMPLES
Example 1
Fixed Bed Reactor Configuration
[0088] After pressurizing and vaporization, methanol can be
provided to a first stage of a dehydration (DME) reactor having an
alumina catalyst therein to form an equilibrium mixture of
methanol, dimethyl ether, and water. The reactor can be operated at
a reactor inlet temperature of 310-320.degree. C. and a pressure of
about 26 bar. Approximately 15-20% of the heat of reaction can be
released in this first step.
[0089] In the fluid bed configuration, the DME reactor effluent
should typically be cooled to moderate the temperature rise over a
second-stage dehydration reactor before passing into multiple,
parallel fixed-bed conversion reactors containing a ZSM-5 to
convert the methanol and dimethyl ether to hydrocarbons and water.
WHSV can be about 1.6. The inlet temperature of the conversion
reactor can be .about.350-370.degree. C., the inlet pressures can
be about 19-23 bar. The reactor outlet temperature can be
.about.410-420.degree. C. About 85% of the reaction heat can be
released in the conversion.
[0090] The conversion of methanol to hydrocarbons and water can be
virtually complete and essentially stoichiometric. The reaction is
typically highly exothermic with an adiabatic temperature rise. The
fixed-bed process can often require a gas recycle to absorb the
heat of reaction keeping the catalyst temperature within an
acceptable temperature range. The recycle, however, can dilute the
concentration of reactants in the reactor feed, thereby slowing the
reaction rate. This dilution effect may be overcome by raising the
reaction pressure.
[0091] After being cooled, the effluent from the MTG conversion
reactor can be separated into three phases: gas, liquid water, and
liquid hydrocarbons. The gas phase can contain mostly light
hydrocarbons, hydrogen, CO and CO.sub.2. Most of the gas can be
recycled with the aid of a recycle compressor to the ZSM-5
conversion reactor. The water phase, which can contain trace
amounts of oxygenated organic compounds, can be treated in a
biological wastewater treatment plant. The hydrocarbon product
containing mainly raw gasoline, dissolved hydrogen, carbon dioxide
and light hydrocarbons (C.sub.1-C.sub.4) can be sent first to the
de-ethanizer. The de-ethanizer bottom product can be sent to the
stabilizer where C.sub.3 and part of the C.sub.4 components can be
removed overhead to the fuel gas system. C.sub.4 and C.sub.5
components can be withdrawn as a side stream. The bottom product
can be fed into a gasoline splitter where it can be separated into
light and heavy gasoline fractions. Each stream can be cooled and
stored. The heavy gasoline fraction, which typically contains
durene, can be passed to the heavy gasoline treatment (HGT)
reactor. In the HGT process, the heavy MTG gasoline, comprising
primarily aromatics, can be processed over a multifunctional metal
acid catalyst. The following reactions can occur:
disproportionation, isomerization, transalkylation, ring
saturation, and dealkylation/cracking. The durene content can be
reduced to less than 2 wt %.
Example 2
Fluid Bed Reactor Configuration
[0092] Methanol can be preheated, vaporized and sent to a dense,
fluid bed reactor. The fluid bed reactor can contain a catalyst
that converts methanol to hydrocarbons. The reaction is typically
exothermic and heat can be removed from the reactor by generating
steam within tubes immersed horizontally in the fluid bed. The
catalyst can be continuously regenerated by burning off coke in air
in a separate regenerator vessel. The hot reactor effluent can
generate high pressure steam before final catalyst removal. The
reactor effluent can be recycled to heat the methanol feed before
cooling in air and thereafter being provided to a three phase
separator. The water can be sent to a treatment plant and the gas
can be compressed and sent along with the liquid hydrocarbon to a
de-ethanizer. The bottoms of the de-ethanizer can feed a
debutanizer to produce C.sub.3 and C.sub.4 feed to an alkylation
unit. The C.sub.5+ gasoline fraction can be blended with alkylate
and butane to give finished gasoline. Optionally, the heavy
fraction of the gasoline can be treated to reduce durene
content.
Example3
Moving Bed Reactor Configuration
[0093] After pressurizing and vaporization, methanol can be
provided to a first moving bed reactor. Because the reaction is
typically highly exothermic, the first reactor can be relatively
small. Catalyst can move down from the first reactor to a second,
larger moving bed reactor and the vapor phase effluent can be
cooled before entering the second reactor. Thereafter, the vapor
phase effluent from the second reactor can be provided to a third
reactor larger than the second reactor. Catalyst can move from the
second reactor to the third reactor. Back mixing can be minimized,
thereby minimizing staging concerns associated with fluid-bed
reactors. WHSV can be highest in the first reactor, decreasing in
the second and third reactors. The system can have low pressure
drop so as to reduce/minimize the recycle compressor cost. The
moving bed reactor can be operated at minimum recycle (approaching
zero). Methanol can be provided between reactors as an interstage
quench. The interstage quench along with different WHSV for each
reactor is believed to control catalyst aging and can optimize the
reactor in addition to allowing a recycle ratio that decreases in
the second and third reactors.
[0094] Table 1 compares the products and methanol utilization for
the configurations of Examples 1-3. Data in Table 1 are indicative
of performance at the beginning of the catalyst life. Data for
Example 2 are estimated from known relationship between fixed-bed
and fluid bed processes. Data for Example 3 are estimated from end
of catalyst cycle of the fixed bed performance since the moving bed
approximates the asymptotic limit of end of life, fixed bed
conditions. The results show that the moving bed can provide a more
desired product distribution and higher methanol utilization.
TABLE-US-00001 TABLE 1 Example 1 Example 2 Example 3 C.sub.5+
gasoline yield 28.5 22.6 35.2 (wt % of feed) aromatics in C.sub.5+
57.1 23 32.7 gasoline (wt %) MeOH utilization to 60.4 48 81.5
C.sub.5+ gasoline
[0095] FIG. 4 illustrates the reactor bed temperature as a function
of bed position for fixed-bed and moving bed reactor configurations
described in Examples 1 and 3. FIG. 4 shows the temperature
(degrees Fahrenheit) of the catalyst bed as a function of the
dimensionless catalyst bed depth, for various points in time during
operation of an adiabatic fixed-bed conversion reactor, as well as
the steady-state temperature profile for the moving bed reactor.
The temperature profile within the fixed-bed reactor can be a
function of time because the catalyst can deactivate continuously;
the feed conversion can occur initially at the entrance of the
catalyst bed, which can be accompanied by a rapid temperature
increase (FIG. 4, left-most curve). The temperature can remain high
through the remaining portion of the catalyst bed, which can
subject the desired products to undesired side reactions in the
fixed-bed process. The steady-state temperature profile for the
moving bed process (FIG. 4) seems to be consistent with the
end-of-cycle profile of the fixed-bed process.
[0096] FIG. 5 illustrates gasoline fraction product yield as a
function of bed position for fixed-bed and moving bed reactor
configurations described in Examples 1 and 3. The yield curves for
the fixed-bed process (along with the temperature profiles) can
evolve with time as the catalyst deactivates, as described
previously. FIG. 5 shows that the gasoline yields at early times in
the catalyst cycle (left-most curve) can increase quickly, but then
decrease throughout the catalyst bed. This decrease can be due to
secondary reactions that consume the gasoline-range product in the
latter portion of the catalyst bed, which can remain at high
temperature due to the adiabatic nature of the fixed-bed process.
The gasoline yields in the moving bed process (FIG. 5) can be
increased/maximized due to the desirable temperature gradient
across the moving bed, as depicted in FIG. 4.
[0097] FIG. 6 illustrates relative catalyst activity as a function
of bed position for fixed bed and moving bed reactor configurations
of Examples 1 and 3. As FIG. 6 shows, the moving bed reactor can
approximate the performance of the fixed bed configuration at the
end of the catalyst cycle. The start of cycle condition (SOC)
appears to show that the catalyst activity can remain constant (and
at its maximum) throughout the catalyst bed; this high activity in
the latter portions of the fixed-bed (FIG. 6, circled) can result
in undesired secondary reactions that can consume the
gasoline-range products formed in the first part of the bed. The
moving bed process can result in a relatively deactivated catalyst
throughout the latter portions of the catalyst bed, which can be
unable to convert the gasoline-range products formed in the first
part of the bed.
[0098] FIG. 7 illustrates oxygenate utilization relative to
catalyst age for fixed bed and moving bed reactor configurations of
Examples 1 and 3. The oxygenate (methanol) utilization is defined
as the fraction of convertible oxygenate (methanol) that has formed
gasoline-range products during the conversion process. The
fixed-bed process can convert a relatively low fraction of
oxygenate to gasoline at early life (FIG. 7, left-most curve) as
described previously. The saw-tooth form of the curves in FIG. 7
can be a result of intermittent catalyst regeneration in the
fixed-bed process, which can result in an abrupt change in the
oxygenate utilization as reactor operation can re-start with
regenerated catalyst. The moving bed design can afford a constant,
near-ideal oxygenate utilization due to a steady-state temperature
and catalyst activity profile as described previously.
[0099] Embodiments described herein and recited in the claims
appended hereto may have one or more of the following advantages
compared to fixed or fluid bed reactor processes: reduced capital
expenditure, reduced catalyst deactivation due to coking, reduced
steam deactivation at the reactor outlet, higher methanol
utilization, more consistent product yield, higher selectivity to
desired products, and/or higher catalyst utilization. All documents
described herein are incorporated by reference herein for purposes
of all jurisdictions where such practice is allowed, including any
priority documents and/or testing procedures to the extent they are
not inconsistent with this text, provided however that any priority
document not named in the initially filed application or filing
documents is NOT incorporated by reference herein. As is apparent
from the foregoing general description and the specific
embodiments, while forms of the invention have been illustrated and
described, various modifications can be made without departing from
the spirit and scope of the invention. Accordingly, it is not
intended that the invention be limited thereby. Likewise, the term
"comprising" is considered synonymous with the term "including" for
purposes of Australian law. Likewise whenever a composition, an
element or a group of elements is preceded with the transitional
phrase "comprising," it is understood that we also contemplate the
same composition or group of elements with transitional phrases
"consisting essentially of," "consisting of," "selected from the
group of consisting of," or "is" preceding the recitation of the
composition, element, or elements and vice versa.
* * * * *