U.S. patent application number 15/046076 was filed with the patent office on 2016-06-16 for synthesis of drop-in liquid fuels and chemicals from methanol, ethanol or syngas using mixed catalysts.
This patent application is currently assigned to Pioneer Energy Inc.. The applicant listed for this patent is Pioneer Energy. Invention is credited to Michael T Kelly, Adam M Kortan, Heather A Rose, Robert M Zubrin.
Application Number | 20160168477 15/046076 |
Document ID | / |
Family ID | 50931663 |
Filed Date | 2016-06-16 |
United States Patent
Application |
20160168477 |
Kind Code |
A1 |
Kortan; Adam M ; et
al. |
June 16, 2016 |
Synthesis of Drop-in Liquid Fuels and Chemicals from Methanol,
Ethanol or Syngas Using Mixed Catalysts
Abstract
The present invention discloses a system for converting
synthesis gas to liquid hydrocarbons with comparable energy content
to gasoline within mixed catalyst bed single reactor or double
reactor systems. Varying catalyst composition and temperature
profiles allow for significant tailoring of reaction conditions to
the specific feedstocks or the desired products.
Inventors: |
Kortan; Adam M; (Golden,
CO) ; Kelly; Michael T; (Lakewood, CO) ; Rose;
Heather A; (Lakewood, CO) ; Zubrin; Robert M;
(Golden, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pioneer Energy |
Lakewood |
CO |
US |
|
|
Assignee: |
Pioneer Energy Inc.
Lakewood
CO
|
Family ID: |
50931663 |
Appl. No.: |
15/046076 |
Filed: |
February 17, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14103615 |
Dec 11, 2013 |
9296665 |
|
|
15046076 |
|
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Current U.S.
Class: |
585/322 |
Current CPC
Class: |
C07C 1/22 20130101; C10G
3/45 20130101; C07C 41/01 20130101; C07C 41/00 20130101; Y02P 30/20
20151101; C10G 3/49 20130101; C07C 29/152 20130101; C10G 50/00
20130101; C10G 2400/02 20130101; C07C 43/043 20130101; C07C 41/00
20130101 |
International
Class: |
C10G 3/00 20060101
C10G003/00; C07C 41/01 20060101 C07C041/01; C07C 29/152 20060101
C07C029/152 |
Claims
1) A method of synthesizing gasoline boiling range hydrocarbons
catalytically from a syngas mixture using a single reactor
containing a homogenous mixture of a methanol synthesis catalyst, a
methanol to dimethyl ether synthesis catalyst and a dimethyl ether
to hydrocarbon synthesis catalyst where: a) The methanol synthesis
catalyst is a single metal or metal oxide, or a combination such as
Cu--ZnO. b) The methanol to dimethyl ether synthesis catalyst is a
methanol dehydration catalyst such as gamma-alumina. c) The
hydrocarbon synthesis catalyst is a zeolite material such as
ZSM-5.
2) The method of claim 1 where the zeolite catalyst is doped with a
transition metal element in the range of 1-10 wt %.
3) The method of claim 2 where the zeolite catalyst is doped with
zinc.
4) The method of claim 1 where the temperature within the reactor
is varied linearly with a cooler inlet and warmer outlet.
5) The method of claim 1 where the pressure inside the reactor is
controlled in the range of atmospheric pressure to 500 psi.
6) The method of claim 1 where the catalyst is comprised of two or
more mixed zones where the initial catalyst has a larger portion of
methanol synthesis catalyst and the subsequent zones have larger
portions of hydrocarbon synthesis catalyst.
7) The method of claim 1 where the H.sub.2/CO ratio of the feed gas
is varied from 1/1 to 2/1.
8) The method of claim 1 where the syngas contains a significant
amount of N.sub.2.
9) The method of claim 1 where the syngas is produced using air as
an oxidant.
10) The method of claim 1 where a second reactor filled with a
zeolite catalyst is used after the first reactor to further convert
lower molecular weight hydrocarbons.
11) The method of claim 10 where the first reactor is operated at a
higher pressure, approximately 200-500 psi, while the second
reactor is operated at atmospheric pressure.
12) The method of claim 1 where the reactor is configured as
portable system for transport and deployment to locations where
feedstocks are abundant for synthesis gas.
13) A method of synthesizing gasoline boiling range hydrocarbons
catalytically from a syngas mixture using two reactors comprising
the steps of: a) Reacting H.sub.2/CO in the first reactor
containing a homogenous mixture of a methanol synthesis catalyst
and a methanol to dimethyl ether synthesis catalyst to form
dimethyl ether, and, b) Reacting dimethyl ether in the second
reactor containing a dimethyl ether to hydrocarbon synthesis
catalyst to form the gasoline boiling range hydrocarbon
product.
14) The method of claim 13 where the methanol synthesis catalyst is
a metal or metal oxide, or combination such as Cu--ZnO.
15) The method of claim 13 where the methanol to dimethyl ether
synthesis catalyst is a methanol dehydration catalyst such as
gamma-alumina.
16) The method of claim 13 where the hydrocarbon synthesis catalyst
is a zeolite material such as ZSM-5.
17) The method of claim 16 where the zeolite catalyst is doped with
a transition metal element in the range of 1-10 wt %.
18) The method of claim 13 where the zeolite catalyst is doped with
zinc.
19) The method of claim 13 where the temperature within the first
reactor is varied in the reactor with a cooler inlet and warmer
outlet.
20) The method of claim 13 where the pressure inside the reactors
is controlled in the range of atmospheric pressure to 500 psi.
21) The method of claim 13 where the catalyst in the first reactor
is comprises of two or more mixed zones where the initial catalyst
has a larger portion of methanol synthesis catalyst and the
subsequent zones have larger portions of methanol dehydration
catalyst.
22) The method of claim 13 where the H.sub.2/CO ratio of the feed
gas is varied from 1/1 to 2/1.
23) The method of claim 13 where the syngas contains a significant
amount of N.sub.2.
24) A method of claim 13 where the syngas is produced using air as
an oxidant.
25) The method of claim 13 where the first reactor is operated at
higher pressure, approximately 200-500 psi, while the second
reactor is operated at atmospheric pressure.
26) The method of claim 13 where the reactor is configured as
portable system for transport and deployment to locations where
feedstocks are abundant for synthesis gas.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 14/103,615 filed 11 Dec. 2013 which is a
non-provisional of and claims the benefit of U.S. Provisional
Application Ser. No. 61/737,019, filed on 13 Dec. 2012 entitled
"Synthesis of Fuels from Methanol or Syngas Using Mixed Catalysts,"
U.S. Provisional Application Ser. No. 61/750,263, filed on 8 Jan.
2013 entitled "Synthesis of Fuels from Ethanol or Mixtures of
Ethanol with Methanol or Water Using Mixed Catalysts," and U.S.
Provisional Application Ser. No. 61/778,861, filed 13 Mar. 2013
entitled "Synthesis of Isopropanol and Olefins" all of which are
incorporated in their entireties herein by reference.
BACKGROUND OF THE INVENTION
[0002] The statements in this section merely provide background
necessary to understand the invention and may not be prior art.
[0003] Petroleum has been the primary source of transportation
fuels for the last century and continues to heavily dominate the
market today. Many economic, political and environmental factors
contribute to the desire for alternatives to petroleum for the
essential transportation fuels. Various alternative fuels are being
examined, but almost all require substantial modifications or
additions to the current infrastructure.
[0004] Examples of fuels considered include alcohols such as
methanol and ethanol, but they require both vehicle modifications
and a new distribution infrastructure as they are corrosive to
existing infrastructure. Examples of other fuels considered include
CNG (compressed natural gas) and LNG (liquified natural gas), but
these require even more extensive engine modifications, bulky and
expensive fuel tanks, and complete changes to the refueling
infrastructure. Other fuels considered include higher alcohols such
as butanol but they have a lower energy density than gasoline.
[0005] For 40 years, a process of converting methanol to gasoline
(MTG) has been known. This process would allow for production of a
gasoline fuel that requires no major infrastructure modifications
while allowing for a larger and more flexible resource base. Since
methanol can be produced from a huge variety of sources including
natural gas, coal, and biomass, it is an attractive process but has
yet to see significant applications due to the relatively low cost
of petroleum products.
[0006] Unfortunately, the MTG process requires multiple steps,
including first transforming methanol to dimethyl ether, then
transforming dimethyl ether to propylene, and finally transforming
propylene to gasoline. This multi-stage system adds complexity and
cost to the MTG process. As a result, the MTG process is not
economically attractive, except when oil prices are extremely high.
Thus, there is a need to develop an economic means for conversion
of methanol to gasoline.
[0007] Ethanol is a major product used as a fuel and chemical
produced both from renewable and petroleum and natural gas feed
stocks. The ethanol to gasoline (ETG) process requires multiple
steps, first transforming ethanol to diethyl ether, then
transforming diethyl ether to ethylene, and finally transforming
ethylene to gasoline. This multistage system adds complexity and
cost to the ETG process. Additionally, ethanol from fermentation
sources is difficult to fully purify as the dehydration process
cannot be completed with simple distillation. As a result the ETG
process is not economically attractive, except when oil prices are
extremely high. Thus there is a need to develop an economic means
for conversion of ethanol to gasoline.
[0008] Due to the parity in the MTG and ETG processes, it is
possible to combine the two alcohols in any ratio and still achieve
highly efficient conversion to gasoline. The ability to freely mix
alcohols allows for a wide range of potential alcohol sources.
Water can also be mixed with the ethanol feed, and while it may be
thermodynamically unfavorable it is still possible to achieve
efficient conversion. The tolerance of water in the feed could
allow for drastically reduced ethanol costs since the ethanol could
be utilized before undergoing several costly distillation and
drying steps.
[0009] The present invention allows for high-efficiency conversion
of ethanol, mixtures of ethanol and methanol, or mixtures of
methanol and ethanol and water to aromatic compounds usable as
gasoline in one step, in one pass, within a single mixed catalyst
reactor. Such a system allows for radically lower plant costs since
fewer independent reactors, condensers, valves, pipes, pumps,
transducers, and control system elements are used, and combining
catalysts leads to higher one-pass conversions and a reduction in
the total material required. The fuels produced from this system
are high energy products that are readily compatible with the
existing transportation fuel infrastructure.
[0010] Therefore, it would be an advancement in the state of the
art to provide a system and method for converting methanol and/or
ethanol and/or mixtures thereof to gasoline-type aromatic
hydrocarbons (hereinafter referred to as "gasoline").
[0011] It is against this background that various embodiments of
the present invention were developed.
BRIEF DESCRIPTION OF THE INVENTION
[0012] The present invention discloses novel methods to synthesize
hydrocarbons.
[0013] In one embodiment, an alcohol is reacted over a mixed
catalyst bed in a single reactor charged with a dehydration
catalyst and a zeolite catalyst. In another embodiment, a method to
synthesize dimethyl ether catalytically from a H.sub.2/CO syngas
mixture using a single reactor containing a homogenous mixture of a
methanol production catalyst and a methanol to dimethyl ether
synthesis catalyst is described. The methanol production catalyst
may be a single metal or metal oxide, or a combination such as
Cu--ZnO. The methanol to dimethyl ether catalyst may be methanol
dehydration catalyst such as gamma-alumina.
[0014] In another embodiment, a method to synthesize gasoline
boiling range hydrocarbons is described where, H.sub.2/CO syngas
mixture is reacted using a single reactor containing a homogenous
mixture of a methanol production catalyst, a methanol to dimethyl
ether synthesis catalyst and a dimethyl ether to hydrocarbon
catalyst.
[0015] In another embodiment, a method to synthesize gasoline
boiling range hydrocarbons catalytically from a H.sub.2/CO syngas
mixture using two reactors is described. The reaction of synthesis
gas H.sub.2/CO in the first reactor containing a homogenous mixture
of a methanol production catalyst and a methanol to dimethyl ether
synthesis catalyst to form dimethyl ether and reaction of dimethyl
ether in the second reactor containing dimethyl ether to
hydrocarbon catalyst to form the gasoline boiling range hydrocarbon
product is described.
[0016] In another embodiment, a method to synthesize gasoline
boiling range hydrocarbons from a light olefin using a single
reactor charged with a zeolite catalyst is described.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 describes the single reactor methanol conversion
system with an optional recycle loop.
[0018] FIG. 2 describes the single reactor methanol conversion
system with an optional hydrogen separation membrane.
[0019] FIG. 3 describes the dual reactor methanol conversion system
with an optional recycle loop and hydrogen separation membrane.
[0020] FIG. 4 describes the single reactor syngas conversion
system.
[0021] FIG. 5 describes the dual reactor syngas conversion
system.
[0022] FIG. 6 describes the single reactor alcohol conversion
system.
DETAILED DESCRIPTION OF THE INVENTION
[0023] In one embodiment, the present invention allows for
high-efficiency conversion of methanol to aromatic compounds usable
as gasoline in one step, in one pass, within a single mixed
catalyst reactor. Such a system allows for radically lower plant
costs since fewer independent reactors, condensers, valves, pipes,
pumps, transducers, and control system elements are used, and
combining catalysts leads to higher one-pass conversions and a
reduction in the total material required. Additionally, modifying
the mixed catalyst ratios allows for much easier tunability of the
process conditions, either in response to the feedstock composition
or for the desired products. The fuels produced from this system
are high energy products that are readily compatible with the
existing transportation fuel infrastructure.
[0024] The present invention involves a system for passing a feed
of methanol into a single fixed bed reactor containing a mixed
catalyst capable of converting the methanol into aromatic
hydrocarbons in the gasoline boiling range. The system converts
methanol efficiently into desired products by combining a catalyst
to dehydrate methanol to dimethyl ether and a catalyst to convert
the dimethyl ether as it is produced into aromatic hydrocarbons. By
intimately mixing the catalyst in a single reactor the products
from dehydration can immediately undergo further reactions and
drive the thermodynamic equilibrium forward.
[0025] In one embodiment of the present invention, because of the
advantages of the described process, the invention is compact
enough to be packaged into a semi-trailer and transported to
locations where waste streams are readily available. For example,
the present invention may be packaged into a portable trailer that
may be taken to a site of a flare gas well (such as the hundreds of
flare gas wells in the Bakken formation in North Dakota) and
utilized to convert the wasted flare gas into valuable
gasoline.
[0026] In another embodiment, there is provided a method for the
manufacture of fuels and chemicals by providing an ethanol feed
into a single fixed bed reactor containing a mixed catalyst capable
of converting the gas into aromatic hydrocarbons in the gasoline
boiling range. The system is able to produce high ethanol
conversion efficiency into the desired products by combining a
catalyst to dehydrate an alcohol to its corresponding ether and a
catalyst to convert the ether as it is produced into aromatic
hydrocarbons. By intimately mixing the catalyst in a single reactor
the products from dehydration can immediately undergo further
reactions and drive the thermodynamic equilibrium forward.
[0027] In another embodiment of this system a mixture of methanol
and ethanol can be used as the feedstock. The same catalysts for
the single component systems can be used and any ratio of methanol
and ethanol can be used.
[0028] In another embodiment of this system a mixture of ethanol
and water can be used as the feedstock. The system is tolerant to a
large range of ethanol/water mixtures, and the system can be
adjusted to produce consistent ethanol space velocities with high
conversion regardless of the concentration of the feed.
[0029] In one embodiment, a gamma-alumina catalyst is used in this
work for the dehydration of methanol and ethanol to their ether
derivatives, but other catalysts that perform the same function
could be used.
[0030] In one embodiment, a transition metal doped ZSM-5 catalyst
is used for the conversion of dehydration products of methanol and
ethanol to aromatics respectively.
[0031] In one embodiment, a transition metal mixed with a main
group metal and doped on ZSM-5 to form a catalyst used for the
conversion of dehydration products of methanol and ethanol to
aromatics respectively.
[0032] In one embodiment, a transition metal selected from the
group consisting of copper, zinc, iron, manganese, cobalt,
zirconium is doped on ZSM-5 to form a catalyst used for the
conversion of dehydration products of methanol and ethanol to
aromatics respectively.
[0033] In one embodiment, a mixture of two or more transition
metals are doped on ZSM-5 to form a catalyst used for the
conversion of dehydration products of methanol and ethanol to
aromatics respectively.
[0034] A preferred catalyst used is a transition metal such as
zinc, but other metals may also be used.
[0035] The catalysts in this system can either be homogenously
mixed in a variety of ratios, or can be mixed as a gradient.
Increased percentages of dehydration catalyst such as gamma-alumina
at the inlet that gradually decrease down the length of the reactor
can provide increased alcohol dehydration initially but taper into
a majority of metal doped zeolite once the methanol has been
converted.
[0036] In one embodiment, to make catalyst preparation and loading
easier, multiple zones of variably mixed catalyst can be employed
in the reactor to make any gradient desired.
[0037] In another embodiment of this reaction a recirculating pump
is used to recycle the waste gas back into the reactor inlet, as
shown in FIG. 1. This allows for the upgrading of small hydrocarbon
products that would otherwise be completely lost as waste products.
It also allows for controlling the space velocity of the gas
through the system, which can be used to modify the kinetics or be
useful in controlling the temperature of the reactor.
[0038] In another embodiment, a hydrogen separation membrane can
also be used in conjunction with the recirculating pump as shown in
FIG. 2. By removing the product hydrogen the partial pressure of
the hydrocarbons in the recycle stream is increased and the
aromatization reaction, which produces hydrogen as a product, would
be more thermodynamically driven towards the products.
[0039] In another embodiment of this reaction, additional reactors
can be utilized after the initial mixed bed reactor in order to
further increase the conversion of small gaseous hydrocarbons.
Since the feed methanol is essentially completely converted into
dimethyl ether or larger products in the first reactor, the
secondary reactors would likely contain only a metal doped zeolite
catalyst. A condenser that removes water and liquid hydrocarbons
from the product stream of the primary reactor would allow for
increased conversion in the secondary reactors since the main
products of the conversion have been removed from the process
stream.
[0040] As an addition to this embodiment a recirculating pump can
be used to recycle the waste gas stream into the secondary
reactors, further increasing the yield of the desired liquid
products. Also, a hydrogen separation membrane can be installed
in-between the primary and secondary reactors to increase the
potential product yields from the secondary reactors, and be used
by itself or in conjunction with the recycle loop.
[0041] This invention can also be used with feedstocks besides
methanol and ethanol including C1 to C5 alcohols as they are
available.
[0042] In one embodiment, carbon monoxide and hydrogen or synthesis
gas (syngas) conversion is preferred. Carbon monoxide conversion to
larger hydrocarbons requires a metal catalyst such as copper,
chromium, iron, nickel, rhodium, ruthenium, zinc, or their oxides
among others to convert the syngas to methanol, and then subsequent
reactions further transform the intermediate methanol to aromatic
hydrocarbon products.
[0043] In one embodiment, a common methanol production catalyst
such as Cu--ZnO can be intimately combined with both a methanol
dehydration catalyst such as gamma-alumina and a hydrocarbon
synthesis catalyst such as metal doped ZSM-5. This process, shown
in FIG. 4, allows for an improved CO conversion to methanol
thermodynamic equilibrium and greater efficiencies. The intimately
mixed catalyst can accomplish the full conversion from syngas to
aromatics in a single reactor.
[0044] In another embodiment, the ratios of the three component
catalyst mixture can be modified within the reactor to achieve
greater conversion. By increasing the proportion of methanol
production catalyst at the inlet the whole system can make better
use the available reactants, and as the CO is converted less of the
catalyst is needed down the length of the reactor. This alteration
of the catalyst ratios within the reactor could be continuous or
could be separated into two or more distinct zones for easier
mixing and loading of the reactor.
[0045] In another embodiment of this system a secondary reactor
containing a catalyst such as metal doped ZSM-5 could be employed
after the primary reactor to further convert small organics to more
desirable larger products.
[0046] In one embodiment of the present invention, because of the
advantages of the described process, the invention is compact
enough to be packaged into a semi-trailer and transported to
locations where waste streams are readily available. For example,
the present invention may be packaged into a portable trailer that
may be taken to a site of a flare gas well (such as the hundreds of
flare gas wells in the Bakken formation in North Dakota) and
utilized to convert the wasted flare gas into valuable chemical and
fuel products.
[0047] In another embodiment of the system, a methanol synthesis
catalyst and a methanol dehydration catalyst can be mixed in a
single reactor to produce dimethyl ether as an end product. The
feed ratio and catalyst composition can be altered to produce
dimethyl ether and water using a 2/1 hydrogen/carbon monoxide
syngas ratio or the ratio can be altered to 1/1 to facilitate the
water gas shift reaction and produce dimethyl ether and carbon
dioxide as primary products. The products can be condensed out of
the gas stream and separated if necessary using standard
distillation techniques.
[0048] In another embodiment of the system a sygas stream with
additional components such as carbon dioxide or nitrogen can be
used.
[0049] In another embodiment of the system, two reactors may be
employed, with the first reactor containing a mixture of the
methanol production catalyst and the methanol dehydration catalyst
and the second reactor containing a hydrocarbon synthesis catalyst
such as the metal doped ZSM-5. In such a system, the first reactor
converts the syngas at high efficiency into dimethyl ether and
water or dimethyl ether and carbon dioxide. After the water is
knocked out in a condenser, the remaining dimethyl ether can then
be converted to aromatics in the metal-doped ZSM-5 reactor.
[0050] In another embodiment of the system a light olefin gas such
as ethylene or propylene from a variety of sources can be converted
to aromatics and larger hydrocarbons by passing them through a
transition metal doped zeolite catalyst. The resulting liquid
products can be used directly as a fuel.
[0051] In another embodiment of the system the light olefin feed
can be a mixture of ethylene and propylene in any ratio.
[0052] In another embodiment of the invention, propylene is
synthesized by the steps of ketonizing acetic acid to form acetone,
hydrogenating acetone to form isopropanol and dehydrating
isopropanol to form propylene.
[0053] In one embodiment of the present invention, because of the
advantages of the described process, the invention is compact
enough to be packaged into a semi-trailer and transported to
locations where waste streams are readily available. For example,
the present invention may be packaged into a portable trailer that
may be taken to a site of a flare gas well (such as the hundreds of
flare gas wells in the Bakken formation in North Dakota) and
utilized to convert the wasted flare gas into valuable
gasoline.
DEFINITIONS
[0054] Unless specifically noted otherwise herein, the definitions
of the terms used are standard definitions used in the art.
Exemplary embodiments, aspects and variations are illustrated in
the figures and drawings, and it is intended that the embodiments,
aspects and variations, and the figures and drawings disclosed
herein are to be considered illustrative and not limiting.
[0055] As used herein, an "alkyl" group is a straight, branched,
cyclic, acylic, saturated or unsaturated, aliphatic group or
alcoholic group having a chain of carbon atoms. A C.sub.1-C.sub.20
alkyl or C.sub.1-C.sub.20alkanol, for example, may include alkyl
groups that have a chain of between 1 and 20 carbon atoms, and
include, for example, the groups methyl, ethyl, propyl, isopropyl,
vinyl, allyl, 1-propenyl, isopropenyl, ethynyl, 1-propynyl,
2-propynyl, 1,3-butadienyl, penta-1,3-dienyl, penta-1,4-dienyl,
hexa-1,3-dienyl, hexa-1,3,5-trienyl, and the like. An alkyl group
may also be represented, for example, as a
--(CR.sup.1R.sup.2).sub.m-- group where R.sup.1 and R.sup.2 are
independently hydrogen or are independently absent, and for
example, m is 1 to 8, and such representation is also intended to
cover both saturated and unsaturated alkyl groups.
[0056] An "alkyl compound(s)" as used herein, is an alkyl
containing 1 to 20 carbons (C.sub.1-C.sub.20 alkyl), and includes
cyclic and acyclic alkanes, alkenes, alcohols, ketones and
aromatics (e.g., benzene, toluene, ethyl benzene etc.) and mixtures
thereof. The alkyl compound may be used as a raw material for
chemical processing, a solvent or the alkyl compound may be used as
a fuel or mixtures of fuels. Such fuel or mixtures of fuels may be
further combined with other fuel or fuel products to form a
gasoline. Non-exclusive examples of an alkyl compound include
butane, 1-butanol, 2-butanol, 2-pentanol, 1-hexanol, 2-hexanol,
2-heptanol, 4-heptanol, 4-heptanone, 3-methyl cyclohexanol,
2,6-dimethyl-4-heptanol and mixtures thereof.
[0057] "Gasoline" is known to comprise of a complex mixture of
volatile hydrocarbons suitable for use as a fuel in a
spark-ignition internal combustion engine. Typically, gasoline
boils over a range of about 27.degree. C. to about 225.degree. C.
Gasoline may consist of a single blendstock, such as the product
from a refinery alkylation unit, or it may comprise of a blend of
several blendstocks. The blending of gasoline is well known in the
art and may include a combination of three to twelve or more
different blendstocks. Optimization of the blending process takes
into account a plurality of characteristics of both the blendstocks
and the resulting gasoline, and may include such characteristics as
cost and various measurements of volatility, octane, boiling point
characteristics and chemical composition. While hydrocarbons
usually represent a major component of gasoline, certain oxygen
containing organic compounds may be included as gasoline
components. In one aspect, such oxygen containing organic compounds
are referred to as "oxygenate" or "oxygenates," and are important
gasoline substitutes such as ethanol and butanol. Oxygenates are
also useful as components in gasoline because they are usually of
high octane and can be a more economical source of gasoline octane
than a high octane hydrocarbon blending component such as alkylate
or reformate.
[0058] Natural gas liquids are the larger hydrocarbon components of
natural gas, including ethane, propane and butane as the major
constituents. These components can be separated from the methane
using simple condensation. This liquid portion of the natural gas
stream can be used as is or further separated using common chemical
engineering techniques.
[0059] Catalysts used in reductions may be supported or
unsupported. A supported catalyst is one in which the active metal
or metals are deposited on a support material; e.g. prepared by
soaking or wetting the support material with a metal solution,
spraying or physical mixing followed by drying, calcination and
finally reduction with hydrogen if necessary to produce the active
catalyst. Catalyst support materials used frequently are porous
solids with high surface areas such as silica, alumina, titania,
magnesia, carbon, zirconia, zeolites etc.
[0060] The dehydration of alcohols can be accomplished using
several catalysts including metal oxides and concentrated acids.
Gamma alumina is an efficient solid catalyst used for this process.
Dehydration of methanol generally forms dimethyl ether while larger
alcohols such as ethanol and propanol form their corresponding
ethers as well as olefins such as ethylene and propylene.
[0061] Zeolites are crystalline aluminosilicates with ordered,
porous structures with well defined pore sizes. Zeolites generally
consist of a tetrahedral network of SiO.sub.2 and Al.sub.2O.sub.3
linked through the oxygen sites. The silica to alumina ratio can be
varied, which changes the acidic character of the zeolite. The
excess negative charge generated by the aluminum ions is balanced
by a counter cation, which is usually sodium or ammonia in the most
simple form. Alternatively, the zeolite can be doped with a metal
cation which displaces the counter cation and alters the properties
of the catalyst. This doping is usually done using the incipient
wetness impregnation technique, which consists of adding a metal
salt dissolved in the minimum amount of water to the zeolite,
heating to allow diffusion, then drying and calcining to achieve
the final catalyst. ZSM-5 has a pore size of 5.4-5.6 angstroms.
Zeolite catalysts have been used for many applications, including
extensive study into using them as sole catalysts of the methanol
to gasoline process.
[0062] The methods of the present invention can comprise, consist
of, or consist essentially of the essential elements and
limitations of the method described herein, as well as any
additional or optional ingredients, components, or limitations
described herein or otherwise useful in synthetic organic
chemistry.
[0063] "Synthesis gas" or "syngas" is a mixture of varying amounts
of carbon monoxide and hydrogen. Syngas maybe produced by the
partial oxidation of materials such as methane, liquid
hydrocarbons, coal, biomass, etc.
[0064] "Biomass" is material obtained from living or recently
living organisms.
[0065] Acetic acid may be made by oxidation of ethanol produced by
fermentation or conversion of synthesis gas to methanol followed by
its carbonylation. Synthesis gas may be obtained in large
quantities from biomass, coal, natural gas, etc.
DETAILED DESCRIPTION OF DRAWINGS
[0066] FIG. 1 describes a single reactor methanol conversion system
where methanol from a liquid resevoir (120) is delivered via an
HPLC pump (121) into a vaporizer (122) heated with heat tape. Gas
flow is mixed with an inert gas from a cylinder (119) and
controlled by a mass flow controller (103). Mixed gas flow can be
preheated with heat tape (131-132). Heated gas enters the reactor
(123) heated with heat tape then passes to the condenser (126)
cooled with a coolant loop (124, 129). Liquid from the condenser is
captured in a sample cylinder (127) and proceeds to liquid product
analysis (130). Gas from condenser passes through a back pressure
regulator (115), is measured by a dry gas meter (116) and is vented
out and analyzed (128). Optionally, the gas can also be
recirculated via a recirculating compressor (125) with flow
measured by a mass flow meter (117) and returned to the reactor
inlet. Pressure is monitored by pressure transducers (106, 118) and
temperature is monitored by thermocouples (101-102, 104-105,
107-114).
[0067] FIG. 2 describes a single reactor methanol conversion system
where methanol from a liquid resevoir (221) is delivered via an
HPLC pump (222) into a vaporizer (223) heated with heat tape. Gas
flow is mixed with an inert gas from a cylinder (220) and
controlled by a mass flow controller (203). Mixed gas flow can be
preheated with heat tape (232-233). Heated gas enters the reactor
(224) heated with heat tape then passes to the condenser (227)
cooled with a coolant loop (225, 230). Liquid from the condenser is
captured in a sample cylinder (228) and proceeds to liquid product
analysis (231). Gas from condenser passes through a back pressure
regulator (215), is measured by a dry gas meter (216) and is vented
out and analyzed (229). Optionally, the gas can also be
recirculated via a recirculating compressor (226) with flow
measured by a mass flow meter (217) and passed through a membrane
gas separator (223). Permeate gas flow is measured by a mass flow
meter (219) then vented out of the system. Retenate gas is returned
to the reactor inlet. Pressure is monitored by pressure transducers
(206, 218) and temperature is monitored by thermocouples (201-202,
204-205, 207-214).
[0068] FIG. 3 describes a dual reactor methanol conversion system
where methanol from a liquid resevoir (335) is delivered via an
HPLC pump (336) into a vaporizer (334) heated with heat tape. Gas
flow is mixed with an inert gas from a cylinder (331) and
controlled by a mass flow controller (304). Mixed gas enters the
first reactor (337) heated with heat tape then passes to the first
condenser cooled with cold house water loop (332, 346). Gas from
condenser passes through a gas separation membrane (338) where the
permeate is monitored by a mass flow meter (315) and vented while
the retenate passes through a back pressure regulator (327) and
enters the second reactor (339) which is heated by heat tape. After
the second reactor the gas stream passes through the second cold
water cooled condenser and the remaining gas passes through a third
condenser (341) which is chilled by a coolant loop (333, 344).
Liquid from all three condensers is collected in a sample cylinder
(342) and removed from the system for liquid analysis (345). The
gas from the cold condenser passes through a back pressure
regulator (327), measured by a dry gas meter (328) and is vented
from the system and analyzed (343). Optionally, some of the gas can
be recirculated using a recirculating pump (340) and measured by a
mass flow meter (329) and returned to the process stream at the
inlet to the gas separation membrane. Pressure is monitored by
pressure transducers (305, 317, 330) and temperature is monitored
by thermocouples (301-303, 306-314, 316, 318-326).
[0069] FIG. 4 describes a single reactor sygnas to dimethyl ether
conversion system where carbon monoxide and hydrogen sources
(417-418) are controlled by mass flow controllers (401-402) and
measured by mass flow meters (403-404). The mixed syngas is
converted in a single reactor (419) heated by heat tape and the
product gasses pass through a condenser (421) chilled by a coolant
loop (420, 424). Liquid products are collected in a sample cylinder
(422) and removed for liquid analysis (425). Gas products pass
through a back pressure regulator (415), are measured by a dry gas
meter (416) and are vented for gas analysis (423). Pressure is
monitored by a pressure transducer (406) and temperature is
monitored by thermocouples (405, 407-414).
[0070] FIG. 5 describes a dual reactor syngas to gasoline
conversion system where carbon monoxide and hydrogen sources
(529-530) are controlled by mass flow controllers (501-502) and
measured by mass flow meters (503-504). Mixed syngas is passes
through the first reactor (533) and into a condenser cooled by cold
house water (531, 540). Gas products pass a back pressure regulator
(527) and are fed into a second reactor (534) and into the second
cold house water condenser. Gas products from that condenser pass
through a coolant loop (532, 538) chilled condenser (535) and any
remaining gas passes through a back pressure regulator (526), is
measured by a dry gas meter (528) and is vented from the system for
gas analysis (537). Liquid from all condensers is collected in a
sample cylinder (536) and removed from the system for liquid
analysis (539). Pressure is monitored by pressure transducers (506,
517) and temperature is measured by thermocouples (505, 507-515,
517-525).
[0071] FIG. 6 describes a single reactor alcohol conversion system
where a premixed feed of alcohols or alcohol and water is stored in
a liquid resevoir (618). An HPLC pump (619) feeds the liquid into a
vaporizer (620) heated with heat tape and can be mixed with an
inert gas (617) controlled by a mass flow controller (603). Mixed
gasses are heated by heat tape (628-629) and fed into the reactor
(621) heated by heat tape. Products from the reactor pass into a
condenser (623) chilled by a coolant loop (622, 626) and liquid
products are collected in a sample cylinder (624) and removed for
liquid analysis (627). Gas products pass through a back pressure
regulator (615), are measured by a dry gas meter (616) and are
vented from the system and analyzed (625). Pressure is monitored by
a pressure transducer (606) and temperature monitored by
thermocouples (601-602, 604-605, 607-614).
EXPERIMENTAL
[0072] Although the following experiments are described in detail,
they are illustrative examples of the inventions described herein
and not limitative of the remainder of the description.
[0073] Reagents and catalysts used were obtained from commercial
sources such as Sigma Aldrich, Alfa Aesar, etc. or prepared through
procedures well known to those with ordinary skill in the art.
[0074] Gas phase products were analyzed with a Varian MicroGC with
four channels: a 20 m 5 A molecular sieve column with Ar carrier, a
20 m 5 A molecular sieve column with He carrier, a 10 m PPQ column
with He carrier and an 8 m CBS column with He carrier. All channels
used thermal conductivity detectors. Calibrations using external
standards were performed for all identified compounds.
[0075] Liquid products were analyzed on an Agilent 6890 5973 GCMS
system equipped with a JW1 DB624 column with dimensions of 30
m.times.250 .mu.m.times.1.4 .mu.m. The method ran at 1 ml/min flow,
with oven temperature at 40.degree. C. for the first two minutes
followed by temperature ramp at 10.degree. C./min to a temperature
of 240.degree. C. which was held for 10 minutes. The solvent delay
was set at 5 minutes. Chemical identities of the obtained products
were confirmed against a NIST 2011 library.
Experiment 1
[0076] The zeolite catalyst used in these examples was ZSM-5 in the
acid form doped with 5 wt % Zn. Commercial HZSM-5 (provided by
Tricat Inc., SiO.sub.2/Al.sub.2O.sub.3=23.5) was doped with
Zn(NO.sub.3).sub.2 using the incipient wetness impregnation
technique. The wetted catalyst was heated to 80.degree. C. for 6
hours, dried at 120.degree. C. for 6 hours and finally calcined at
600.degree. C. for 6 hours. Gamma-alumina catalyst was obtained
from a commercial source (Tricat Inc.) and used as received. The
reactor system for this experiment, illustrated in FIG. 1,
consisted of an ASA schedule 40 steel pipe reactor with a 10:1 form
factor and 1.5 inch diameter, for an internal volume of
approximately 0.5 L. Temperatures were measured by thermocouples
running the length of the bed and measured from the center of the
reactor. Pressure was monitored by a pressure transducer.
[0077] For this experiment the reactor was loaded with 25% (v/v)
gamma-alumina and 75% Zn-ZSM-5. The catalysts were measured and
homogenously mixed prior to loading the reactor. Total catalyst
weight was approximately 300 g.
[0078] Methanol was introduced to the system via a HPLC pump and a
vaporizer and then combined with a He carrier gas that was
controlled by a mass flow controller. The methanol flow rates were
varied from 0.5 to 5 mL/min and the He flow rates from 0.15 to 1
SLPM.
[0079] The pressure inside the reactor was kept at nominally
atmospheric pressure. Temperatures inside the reactor were
controlled so that the inlet temperature was 200.degree. C. and the
temperature increased approximately linearly to the outlet which
was at 450.degree. C.
[0080] After exiting the reactor the product stream passed through
a condenser to separate out the liquid products, and then the
remaining gas stream either left the system through a dry gas meter
or was recycled through the reactor using a recirculation pump.
Liquid samples were massed and the composition determined through
GC-MS using the procedure described above. Gas samples were taken
at regular intervals and the gas composition was determined with GC
analysis as described above.
[0081] Selected samples that show the results of process variable
changes are shown in Table 1 A. The system efficiency is reported
as the organic liquid yield, which is ratio of the total organic
liquid product mass divided by the organic fraction of the input
methanol.
organic liquid yield efficiency = mass org liq mass MeOH * 0.438 *
100 % ##EQU00001##
[0082] Typical gas and liquid product distributions for all
experiments with a methanol feedstock are shown in Table 1B for
reference.
TABLE-US-00001 TABLE 1A Sample # 1 2 3 4 5 Methanol GHSV (h.sup.-1)
33 67 134 67 67 He GHSV (h.sup.-1) 120 18 18 18 18 Total Input GHSV
(h.sup.-1) 153 85 152 85 85 Approximate 0 0 0 0.75 1.5
Recirculation Ratio Organic Liquid Yield 60.4 57.8 57.6 59.6 57.8
Efficiency (%)
TABLE-US-00002 TABLE 1B Component Wt % Water 55.7 H.sub.2 0.5 CO
0.1 CO.sub.2 0.2 Methane 0.6 Ethylene 0.3 Ethane 0.3 Propane 0.4
Dimethyl Ether 4.6 i-Butane 2.9 n-Butane 0.7 Pentane 0.6 Benzene
0.3 Toluene 4.3 C8 aromatics 11.9 C9 aromatics 9.4 C10 aromatics
5.6 C11 aromatics 0.9 C12 aromatics 0.6
Experiment 2
[0083] The same reactor system from EXPERIMENT 1 was used except a
gradient composition mixed bed catalyst was used. The first third
of the reactor was packed with homogenously mixed 75% gamma-alumina
and 25% Zn-ZSM-5 (v/v) while the rest of the reactor was packed
with 25% gamma-alumina and 75% Zn-ZSM-5. The temperature varied
linearly from 200.degree. C. at the inlet to 450.degree. C. at the
outlet, and the pressure was maintained at nominally atmospheric
pressure. No inert diluent gas was used in these tests. The effects
of other process variables are detailed in Table 2.
TABLE-US-00003 TABLE 2 Sample # 6 7 8 9 10 11 12 13 Methanol 67 67
67 67 134 200 267 334 GHSV (h.sup.-1) Approximate 0 1 2 4 0.9 0.6
0.5 0.4 Recirculation Ratio Organic 66.6 72.4 68.1 67.5 59.8 53.0
55.5 44.9 Liquid Yield (%)
Experiment 3
[0084] This experiment used the two reactor system as described in
FIG. 2. Reactor 1 was a mixed-bed, gradient reactor with the first
third consisting of 75% gamma-alumina and 25% Zn-ZSM-5 (v/v) while
the rest of the reactor was packed with 25% gamma-alumina and 75%
Zn-ZSM-5. Temperatures in the first reactor varied linearly from
200.degree. C. at the inlet to 400.degree. C. at the outlet.
Reactor 2 was packed with Zn-ZSM-5 only and was held at nominally
atmospheric pressure and 400.degree. C. The pressure of the first
reactor was varied as shown in Table 3. A hydrogen separation
membrane was also included in between the reactors for some tests.
Sample 17 included a recirculation loop that fed the product gas
into the system immediately before the separation membrane.
TABLE-US-00004 TABLE 3 Sample # 14 15 16 17 Methanol GHSV
(h.sup.-1) 267 267 281 267 Membrane Used no yes yes yes Reactor
Pressure (psig) 0 30 80 35 Recirculation Rate 0 0 0 4.5 Organic
Liquid Yield (%) 73.8 72.9 64.4 71.7 Total Product Distribution (wt
%) Water 47.7 50.3 49.1 56.2 H.sub.2 1.6 1.3 1.1 0.4 CO 2.7 1.6 2.7
1.3 CO.sub.2 4.0 4.9 2.5 0.4 Hydrocarbons 43.9 41.9 44.5 41.7
Hydrocarbon Composition (wt %) Methane 4.4 4.3 6.8 4.0 Ethylene 0.3
0.6 0.3 0.1 Ethane 1.9 0.4 1.7 1.6 Propane 0.3 0.4 0.3 0.0 Dimethyl
Ether 13.4 5.8 7.2 6.8 i-Butane 7.5 5.1 3.8 2.1 n-Butane 2.9 1.4
1.3 1.1 Pentane 0.0 1.7 1.1 0.0 Benzene 0.5 0.5 0.5 0.2 Toluene 6.0
5.4 5.4 4.4 C8 Aromatics 22.6 22.7 21.5 26.6 C9 Aromatics 23.1 26.3
24.5 30.9 C10 Aromatics 12.9 20.3 20.4 18.7 C11 Aromatics 1.7 2.8
2.5 1.9 C12+ Aromatics 2.5 2.4 2.6 1.5
Experiment 4
[0085] The reactor system for this experiment is illustrated in
FIG. 1. For this experiment the reactor was loaded with 50% (v/v)
gamma-alumina and 50% Zn-ZSM-5. The catalysts were measured and
homogenously mixed prior to loading the reactor. Total catalyst
weight was approximately 300 g.
[0086] Ethanol was introduced to the system via a HPLC pump and a
vaporizer. The ethanol flow rate was 1 mL/min which translates to a
GHSV of 46 h.sup.-1.
[0087] Temperatures inside the reactor were controlled so that the
inlet temperature was 200.degree. C. and the temperature increased
approximately linearly to the outlet which was at 400.degree. C.
After exiting the reactor the product stream passed through a
condenser to separate out the liquid products, and then the
remaining gas stream left the system through a dry gas meter.
Liquid samples were massed and the composition determined through
GC-MS using the procedure described above. Gas samples were taken
at regular intervals and the gas composition was determined with GC
analysis as described above.
[0088] Selected samples that show typical results and the influence
of pressure changes are shown in Table 4. The system efficiency is
reported as the organic liquid yield, which is ratio of the total
organic liquid product mass divided by the organic fraction of the
input ethanol.
organic liquid yield efficiency = mass org liq mass EtOH * 0.609 *
100 % ##EQU00002##
TABLE-US-00005 TABLE 4 Sample # 18 19 Reactor Pressure (psi) 5 100
Organic Liquid Yield Efficiency (%) 60.4 57.4 Total Product
Distribution (wt %) Water 37.0 39.0 H.sub.2 1.2 1.0 CO 0.1 0.3
CO.sub.2 0.2 0.8 Hydrocarbons 61.5 59.0 Hydrocarbon Composition (wt
%) Methane 0.7 1.0 Ethylene 1.0 0.6 Ethane 1.6 3.3 Propane 17.2
20.2 i-Butane 13.7 6.5 n-Butane 4.3 2.4 Pentane 0.0 2.8 Benzene 1.8
1.8 Toluene 15.0 12.0 C8 Aromatics 24.8 21.3 C9 Aromatics 12.6 13.2
C10 Aromatics 4.0 7.0 C11 Aromatics 0.9 3.0 C12+ Aromatics 2.4
4.9
Experiment 5
[0089] The same reactor system from EXPERIMENT 4 was used except
the feedstock was mixed methanol and ethanol. The alcohols were
mixed in a common reservoir and pumped as a single feed. The
temperature varied linearly from 225.degree. C. at the inlet to
400.degree. C. at the outlet, and the pressure was maintained at
nominally atmospheric pressure. Efficiency was calculated similarly
to the equation in EXPERIMENT 4 but accounting for the mixed nature
of the feed. The typical results of the feedstock variations are
shown in Table 5.
TABLE-US-00006 TABLE 5 Sample # 20 21 Methanol:Ethanol Ratio of
Feed 1:1 3:1 Organic Fraction of Feed (%) 53.8 49.4 Organic Liquid
Yield (%) 64.4 67.9 Total Product Distribution (wt %) Water 51.4
49.1 H.sub.2 0.6 1.0 CO 0.1 0.2 CO.sub.2 0.2 0.3 Hydrocarbons 47.7
49.4 Hydrocarbon Composition (wt %) Methane 0.6 1.1 Ethylene 1.0
1.5 Ethane 0.9 1.1 Propane 1.1 1.7 Dimethyl Ether 10.7 14.5
i-Butane 9.2 11.9 n-Butane 2.9 3.0 Pentane 1.0 2.1 Benzene 1.3 1.0
Toluene 14.0 11.5 C8 Aromatics 28.2 24.0 C9 Aromatics 17.7 16.3 C10
Aromatics 8.6 8.9 C11 Aromatics 1.1 0.5 C12+ Aromatics 1.8 0.9
Experiment 6
[0090] For this experiment the same reactor setup was used as in
the previous two experiments. The feedstock was a mixture of
ethanol and water which were mixed in a single reservoir and pumped
together. The flow rates were adjusted so that the ethanol GHSV was
approximately 46 h.sup.-1 for all tests. The reactor temperature
varied linearly from 250.degree. C. at the inlet to 400.degree. C.
at the outlet, and the system was maintained at atmospheric
pressure. Results of the variations of the feed ethanol/water ratio
are shown in Table 6. The organic liquid yield is calculated as in
EXPERIMENT 4 and only considers the ethanol content of the
feed.
TABLE-US-00007 TABLE 6 Sample # 22 23 Ethanol:Water Ratio of Feed
9:1 1:1 Organic Liquid Yield (%) 65.3 60.4 Total Product
Distribution (wt %) Water 47.3 73.3 H.sub.2 1.0 0.7 CO 0.1 0.2
CO.sub.2 0.2 0.8 Hydrocarbons 51.5 25.1 Hydrocarbon Composition (wt
%) Methane 0.6 1.1 Ethylene 1.0 2.7 Ethane 1.4 1.3 Propane 10.4
13.0 i-Butane 8.5 14.6 n-Butane 2.3 4.6 Pentane 2.0 3.5 Benzene 1.7
1.0 Toluene 16.2 11.2 C8 Aromatics 29.0 21.8 C9 Aromatics 17.6 18.7
C10 Aromatics 6.1 4.7 C11 Aromatics 1.4 0.7 C12+ Aromatics 2.0
1.1
Experiment 7
[0091] The conversion of a H.sub.2/CO mixture utilized the reactor
system shown in FIG. 4, with the same sized reactor and components
as in the previous experiments. Catalyst composition varied between
tests but always including the same gamma-alumina and Zn-ZSM-5 used
previously, and additionally the CO reduction catalyst Cu--ZnO
(Unicat). Sample 24 used a reactor containing equal volume portions
of gamma-alumina, Zn-ZSM-5 and Cu--ZnO mixed homogenously. Sample
25 consisted of equal volumes of gamma-alumina and Cu--ZnO for the
first half of the reactor, then only Zn-ZSM-5 in the second half.
In all cases the catalyst was reduced for 16 hours at 180.degree.
C. with a 5% H.sub.2 gas stream (balance N.sub.2) flowing at 0.5
SLPM, then for 1 hour at the same temperature with 100% H.sub.2.
The reactor was always kept in a reducing environment or this
procedure was repeated before testing.
[0092] The reactor temperatures were controlled with an
approximately linear gradient with the inlet cooler than the
outlet. The effect of the temperature gradient size is shown in
Table 7.
TABLE-US-00008 TABLE 7 Sample # 24 25 H.sub.2/CO Feed Ratio 2/1 2/1
Total GHSV (h.sup.-1) 200 174 Reactor Pressure (psig) 300 285
Reactor Temperature (.degree. C.) 225-300 200-420 CO conversion (%)
86.5 67.0 Total Product Distribution (wt %) Hydrocarbon 19.5 15.1
H.sub.2 7.2 9.2 CO 13.1 29.9 CO.sub.2 55.6 40.0 H.sub.2O 4.5 5.7
Hydrocarbon Composition (wt %) Methane 4.3 12.9 Ethane 17.0 21.5
Ethylene 0.0 0.0 Propane 27.7 37.7 i-butane 29.4 25.2 n-butane 8.0
0.0 C6+ aliphatic 1.8 0.0 Benzene 0.0 0.0 Toluene 0.4 0.0 C8
aromatic 0.4 0.0 C9 aromatic 0.8 0.4 C10 aromatic 4.1 1.6 C11+
aromatic 2.9 0.7
Experiment 8
[0093] This experiment utilized a two reactor syngas conversion
system as shown in FIG. 5. The first reactor employed a mixed
catalyst for syngas conversion to dimethyl ether which was then
converted to larger hydrocarbons in a second reactor. The catalyst
in Reactor 1 was homogenously mixed Cu--ZnO and gamma-alumina, each
one half by volume. The catalyst in the second reactor was all
Zn-ZSM-5. Pressures around 300 psi in the first reactor encouraged
syngas conversion while ambient pressure in the second reactor
favored aromatic hydrocarbon production. The feed H.sub.2/CO ratio
was varied from 1 to 2. Typical results of changing the process
variables are shown in Table 8.
TABLE-US-00009 TABLE 8 Sample # 26 27 H.sub.2/CO Feed Ratio 2/1 1/1
Total GHSV (h.sup.-1) 174 230 Reactor 1 Temperature (.degree. C.)
250 175-275 Reactor 2 Temperature (.degree. C.) 400 450 CO
Conversion (%) 60.9 64.9 Total Product Distribution (wt %)
Hydrocarbon 17.5 16.0 H.sub.2 8.8 2.7 CO 30.4 29.5 CO.sub.2 34.2
44.1 H.sub.2O 9.2 7.7 Hydrocarbon Composition (wt %) Methane 7.5
6.2 Ethane 4.6 4.3 Ethylene 0.1 1.7 Propane 22.7 18.3 i-butane 26.5
10.4 n-butane 0.0 0.0 Benzene 0.1 1.2 Toluene 4.1 11.0 C8 aromatic
13.1 23.8 C9 aromatic 11.2 15.0 C10 aromatic 7.4 6.4 C11+ aromatic
2.6 1.7
Experiment 9
[0094] The type of system described in EXPERIMENT 8 can also be
used to produce dimethyl ether as an end product. A single reactor
was loaded with the top 3/4 homogenously mixed Cu--ZnO and
gamma-alumina, each one half by volume, and the bottom 1/4 was pure
gamma-alumina. The H.sub.2/CO ratio of the feed was kept between 1
and 1.3 to promote the consumption of water via the water gas shift
reaction to drive the thermodynamics forward. Pressures around 300
psi encouraged syngas production and facilitated condensation of
the dimethyl ether and some CO.sub.2 in a condenser held between
-30 and -40.degree. C.
TABLE-US-00010 TABLE 9 Sample # 28 H.sub.2/CO.sub.2 Feed Ratio 1.3
Reactor Temperature (.degree. C.) 250-275 Total Product
Distribution (wt %) H.sub.2 4.0 CO 40.3 CO.sub.2 31.7 Methane 0.1
Dimethyl Ether 23.1 Dimethyl Ether Production Yield (%) 54 Dimethyl
Ether Captured (%) 89 DME/CO.sub.2 Capture Ratio 2.05
Experiment 10
[0095] The type of system tested in EXPERIMENT 9 could also be used
with a syngas feed that contained a contaminate from the syngas
production such as carbon dioxide or nitrogen. The same reactor as
in EXPERIMENT 9 was used for tests with carbon dioxide. A reactor
loaded with the top 7/8 as CuO--ZnO and gamma-alumina each one half
by volume and the bottom 1/8 was pure gamma-alumina. In all cases
the internal reactor volume was 0.5 L. Additional process variables
and results are detailed in Table 10.
TABLE-US-00011 TABLE 10 Sample # 29 30 31 Feed Rate (SLPM) H.sub.2
1.8 1.6 1.3 CO 0.3 0.5 0.7 CO.sub.2 0.6 0 0 N.sub.2 0 1.8 1.8
Reactor Pressure (psig) 284 286 393 Reactor Temperature (.degree.
C.) 230-260 160-260 140-270 Total Product Distribution (wt %)
H.sub.2 64.7 36.9 28.2 CO 8.7 7.1 9.9 CO.sub.2 24.6 2.5 3.8 N.sub.2
0 54.9 54.2 Dimethyl Ether 2.0 2.1 3.0 CO Conversion (%) 54 54 58
Dimethyl Ether Selectivity (%) 89 62 61
Experiment 11
[0096] To test the feasibility of dimethyl ether conversion to
larger hydrocarbons pure dimethyl ether was fed into a reactor
containing only Zn-ZSM-5. The reactor was kept at atmospheric
pressure and the dimethyl ether gas was fed at a GHSV of 50
h.sup.-1. The results of temperature variations are shown in Table
11.
TABLE-US-00012 TABLE 11 Sample # 32 33 34 35 Temperature (.degree.
C.) 350 400 450 500 Organic Liquid Yield Efficiency (%) 52.1 51.9
62.4 60.6 Total Product Distribution (wt %) Water 39.7 36.7 27.2
23.8 H.sub.2 0.9 1.7 2.7 3.4 CO 0.2 0.5 0.8 2.2 CO.sub.2 0.4 1.7
4.7 13.5 Hydrocarbons 49.2 48.3 54.2 52.2 Unreacted Dimethyl Ether
9.54 11.18 10.34 5.0 Hydrocarbon Composition (wt %) Methane 1.4 3.1
5.6 9.5 Ethylene 0.2 0.4 0.5 0.5 Ethane 0.9 1.6 2.7 4.2 Propane 0.1
0.3 0.0 0.0 i-Butane 7.9 15.2 4.2 2.6 n-Butane 1.8 5.0 2.2 2.2
Pentane 0.0 1.8 3.4 3.6 Benzene 1.1 1.6 3.0 4.0 Toluene 9.8 12.6
15.5 14.5 C8 Aromatics 27.1 26.9 28.6 24.2 C9 Aromatics 23.8 17.7
18.7 17.3 C10 Aromatics 18.2 10.5 11.0 10.9 C11 Aromatics 2.8 1.1
1.8 2.3 C12+ Aromatics 4.8 2.3 3.0 4.2
Experiment 12
[0097] To test the feasibility of producing aromatic hydrocarbons
from ethylene, propylene, and their mixtures, a gas containing one
or both components was fed into a reactor containing only Zn-ZSM-5.
The reactor had a volume of 0.5 L, was kept at atmospheric
pressure, and the olefin feed was fed at a GHSV of 90-120 h.sup.-1.
The results of feed composition and temperature variations are
shown in Table 12.
TABLE-US-00013 TABLE 12 Sample # 36 37 38 39 Ethylene Flow Rate
(SLPM) 1.0 0.5 0.5 0.25 Propylene Flow Rate (SLPM) 0.0 0.5 0.25 0.5
Temperature (.degree. C.) 450 450 350 350 Organic Liquid Yield
Efficiency (%) 39.2 36.8 32.9 31.7 Product Composition (wt %)
Hydrogen 2.1 2.1 1.2 0.9 Methane 8.3 7.6 2.7 2.0 Ethylene 0.0 0.0
0.4 0.2 Ethane 22.4 14.7 4.5 2.7 Propylene 13.2 17.8 20.5 21.3
Propane 0.0 0.0 0.0 0.0 i-Butane 1.7 2.6 11.6 12.9 n-Butane 1.4 2.3
5.0 5.8 Pentane 0.0 0.6 3.1 4.1 Benzene 1.7 4.7 1.9 1.7 Toluene 3.7
8.0 4.2 5.3 C8 Aromatics 8.2 13.6 9.8 12.2 C9 Aromatics 7.9 6.8 9.4
10.3 C10 Aromatics 7.5 3.9 9.9 8.5 C11 Aromatics 6.3 4.8 8.2 7.3
C12+ Aromatics 11.9 10.4 7.7 4.8
Experiment 13
[0098] Catalysts containing CeO.sub.2 and MnO.sub.2 deposited on
alumina are prepared by impregnation supports with aqueous
solutions of precursors using the incipient wetness technique. The
impregnated samples are then dried at 121.degree. C. for 12 h and
then calcined at 450.degree. C. for 3 h in a stream of air. The
ketonization is performed in a typical fixed bed tubular quartz
reactor with 1 g of catalyst and the reactants are delivered to the
reactor using a pump with liquid hourly space velocity (LHSV): 0.25
cc/g catalyst/h. The ketonization process is performed at a
temperature range of 250-450.degree. C. Quantitative conversion of
the acid was noted at 350.degree. C. in the presence of the
following catalysts: 10 and 20 wt. percent
MnO.sub.2/Al.sub.2O.sub.3, 20 wt. percent MnO.sub.2/TiO.sub.2, 20
wt. percent CeO.sub.2 Al.sub.2O.sub.3 and 20 wt.-%
CeO.sub.2/TiO.sub.2. The highest activity is exhibited by alumina
supported catalysts. At 325.degree. C. and 350.degree. C., 96%
yield of acetone was obtained from 20% MnO.sub.2 on alumina.
Experiment 14
[0099] In a cylindrical reactor about 5.5 L in volume, 3765 gm of
3.2.times.3 2 mm tablets of CuO--ZnO catalyst is added and the
reactor purged with nitrogen. Isopropanol containing 2% water is
pumped over the catalyst bed at 10 L/hr along with hydrogen gas at
2000 SLPH (Standard L/hr) as the pressure is around 435 psig. The
catalyst bed is heated to 100.degree. C. and catalyst reduced for 3
hours. After reduction of the catalyst, isopropanol flow is raised
to 25 L/hr and hydrogen flow rate to about 550 SLPH with the
reactor pressure at about 290 psig. The reactor temperature is
raised to 140.degree. C. and acetone with 2% water is passed
through the reactor at 1.64 SLPH. The temperature of the lower part
of the reactor rose to 160.degree. C. due to exotherm. The reaction
is continued with the reactor top at 140.degree. C. and pressure at
290 psig as product is collected. GC analysis indicates 98.5%
acetone conversion with 98.6 selectivity for isopropanol. Morizane
et al U.S. Pat. No. 8,283,504 B2
Energy Analysis
[0100] calorimetry was performed on representative samples of the
liquid products in order to measure the energy content of the fuel.
For reference, methanol and ethanol have energy densities of 22.6
kJ/g and 29.7 kJ/g, respectively. The energy density of gasoline is
about 45 kJ/g. Results of the analysis are reported in Table 13 and
show that the fuels produced in this system are comparable to
modern petroleum derived fuels.
TABLE-US-00014 TABLE 13 Experi- Energy ment Sample Density # #
Feedstock Reactor System (kJ/g) 1 3 methanol single reactor
homogenous 43.0 catalyst 2 10 methanol single reactor gradient
catalyst 43.1 2 11 methanol single reactor gradient catalyst 43.0 2
12 methanol single reactor gradient catalyst 43.1 2 13 methanol
single reactor gradient catalyst 42.8 3 14 methanol two reactor
gradient catalyst 42.6 3 15 methanol two reactor gradient catalyst
42.7 3 16 methanol two reactor gradient catalyst 42.6 3 17 methanol
two reactor gradient catalyst 42.4 7 24 syngas single reactor
homogenous 44.7 catalyst 8 27 syngas two reactor homogenous
catalyst 42.3
* * * * *