U.S. patent application number 13/772700 was filed with the patent office on 2014-08-21 for in-situ upgrading of biomass pyrolysis vapor using acid catalyst and alcohol.
This patent application is currently assigned to Chevron U.S.A. Inc.. The applicant listed for this patent is Armando Joseph Belardinelli, Curtis L. Krause, Yunquan Liu. Invention is credited to Armando Joseph Belardinelli, Curtis L. Krause, Yunquan Liu.
Application Number | 20140230319 13/772700 |
Document ID | / |
Family ID | 51350086 |
Filed Date | 2014-08-21 |
United States Patent
Application |
20140230319 |
Kind Code |
A1 |
Liu; Yunquan ; et
al. |
August 21, 2014 |
IN-SITU UPGRADING OF BIOMASS PYROLYSIS VAPOR USING ACID CATALYST
AND ALCOHOL
Abstract
Processes for thermal conversion of biomass are provided. The
processes involve upgrading the pyrolysis vapor from a pyrolysis
reactor. The steps include thermally converting a biomass feedstock
in a pyrolysis reactor, recovering a pyrolysis vapor from the
reactor, passing the pyrolysis vapor in contact with an acid
catalyst in the presence of alcohol, and converting the resulting
upgraded pyrolysis vapor into a liquid product. The resulting
biooil liquid product is more refined, and the overall processes
offer economic and energy efficiency.
Inventors: |
Liu; Yunquan; (Xiamen,
CN) ; Belardinelli; Armando Joseph; (Sugar Land,
TX) ; Krause; Curtis L.; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Liu; Yunquan
Belardinelli; Armando Joseph
Krause; Curtis L. |
Xiamen
Sugar Land
Houston |
TX
TX |
CN
US
US |
|
|
Assignee: |
Chevron U.S.A. Inc.
San Ramon
CA
|
Family ID: |
51350086 |
Appl. No.: |
13/772700 |
Filed: |
February 21, 2013 |
Current U.S.
Class: |
44/388 |
Current CPC
Class: |
C10G 67/02 20130101;
Y02P 30/20 20151101; C10G 2400/04 20130101; C10L 1/19 20130101;
C10G 2400/02 20130101; C10G 3/46 20130101; C10G 3/50 20130101; C10G
3/42 20130101; C10L 1/02 20130101; C10G 3/48 20130101 |
Class at
Publication: |
44/388 |
International
Class: |
C10L 1/19 20060101
C10L001/19 |
Claims
1. A process for the thermal conversion of biomass comprising the
steps of: a) thermal conversion of a biomass feedstock in a
pyrolysis reactor; b) recovering a pyrolysis vapor from the
reactor; c) passing the pyrolysis vapor in contact with an acid
catalyst in the presence of an alcohol to produce an upgraded
pyrolysis vapor; and d) converting the upgraded pyrolysis vapor
from step c) into a liquid product.
2. The process of claim 1, wherein the acid catalyst comprises a
sulfated zirconium catalyst, a zeolite .beta. or Nafion-SiO2
catalyst.
3. The process of claim 1, wherein the acid catalyst comprises a
zeolite .beta..
4. The process of claim 1, wherein the alcohol is methanol or
ethanol.
5. The process of claim 1, wherein the alcohol is injected into a
stream containing the pyrolysis vapor passed in contact with the
acid catalyst.
6. The process of claim 1, wherein the liquid product has a pH in a
range of from about 2 to about 5.
Description
TECHNICAL FIELD
[0001] The present application relates to a process of upgrading
biomass pyrolysis vapor. More specifically, the present application
relates to a process of in-situ upgrading of biomass pyrolysis
vapor using a multi-layer catalyst bed or a cascade of catalytic
reactors.
BACKGROUND
[0002] With the diminishing supply of fossil fuels, the use of
renewable energy sources is becoming increasingly important as a
feedstock for production of hydrocarbon compounds. Thermal
conversion of carbonaceous materials, such as biomass and waste,
can play an important role to provide materials that can replace
fossil fuels. These conversions can be accomplished by pyrolysis
processes.
[0003] Pyrolysis is one of two major pathways for converting
biomass into fuels or chemicals in a thermochemical platform. The
major product from a common fast pyrolysis process is called
biocrude or biooil, a dark brown liquid that generally is acidic
and has high oxygen and water content, which are characteristics
that are usually not favored by existing refinery equipment or
processes used for further processing to transportation fuels. For
instance, the oxygen content could be 50 weight percent (wt %) or
higher in biooil, thus requiring a high amount of hydrogen to
upgrade the biooil into hydrocarbon fuels via hydroprocessing,
which makes the process economically unattractive. In addition, the
acidity of biooil causes the biooil to be corrosive to existing
pipelines. Moreover, the water content is typically 20 to 30 wt %
and the biooil is immiscible with petroleum crude, which makes
co-refining difficult. Therefore, biooils with improved properties,
such as with less oxygen, less water, and close to neutral pH,
would be preferred.
[0004] Currently, most research on improving the properties of
biooil has been focused on post-pyrolysis treatment involving
upgrading the liquid biooil obtained from fast pyrolysis with
hydroprocessing or hydrotreating, and other reactions like
esterification. However, little or no effort has been put into in
situ catalytic upgrading of pyrolysis vapor before it is condensed
into liquid. For example, one common biooil upgrading method is to
first separate it into two phases (aqueous and lignin phase), and
then use the pyrolytic lignin phase (or organic phase) for
hydroprocessing, while the aqueous phase is passed onto
steam-reforming to generate the hydrogen required by the
hydroprocessing. Although this approach may work, one distinct
disadvantage is that both the aqueous and lignin phases have to be
reheated up to high temperatures for steam reforming and
hydroprocessing, which would require extra heat or energy, thus
considerably reducing the overall thermal efficiency of the
process.
[0005] Biomass-derived pyrolysis oil has the potential to replace
up to 60 percent (%) of transportation fuels, thereby reducing the
dependency on conventional petroleum and reducing its environmental
impact. Therefore, there is a need in the industry for a process
that is more economical and energy efficient for converting biomass
to fuels.
SUMMARY
[0006] The present invention provides a process for in-situ
upgrading of biomass pyrolysis vapor using a multi-layered catalyst
bed or cascaded catalytic reactors. In one aspect, the present
process for the thermal conversion of biomass comprises the steps
of a) thermal conversion of a biomass feedstock in a pyrolysis
reactor, b) recovering a pyrolysis vapor from the reactor, c)
passing the pyrolysis vapor in contact with a cracking catalyst, a
water-gas shift reaction catalyst, a hydrotreating catalyst, and an
acid catalyst, and d) converting the resulting pyrolysis vapor from
step c) into a liquid product.
[0007] In one other aspect, the present process for the thermal
conversion of biomass comprises the steps of a) thermal conversion
of a biomass feedstock in a pyrolysis reactor, b) recovering a
pyrolysis vapor from the reactor, c) passing the pyrolysis vapor in
contact with an acid catalyst in the presence of an alcohol, and d)
converting the resulting pyrolysis vapor from step c) into a liquid
product.
[0008] In another aspect, the present process for the thermal
conversion of biomass comprises the steps of a) thermal conversion
of a biomass feedstock in a pyrolysis reactor, b) recovering a
pyrolysis vapor from the reactor, c) passing the pyrolysis vapor in
contact with a water-gas shift reaction catalyst and a
hydrotreating catalyst, and d) converting the resulting pyrolysis
vapor from step c) into a liquid product.
[0009] In yet another aspect, the present process for the thermal
conversion of biomass comprises the steps of a) thermal conversion
of a biomass feedstock in a pyrolysis reactor, b) recovering a
pyrolysis vapor from the reactor, c) passing the pyrolysis vapor in
contact with a cracking catalyst, a water-gas shift reaction
catalyst, and a hydrotreating catalyst, and d) converting the
resulting pyrolysis vapor from step c) into a liquid product.
[0010] Among other factors, it has been found that by in-situ
upgrading the biomass pyrolysis vapor using the series of catalysts
of the present processes, a liquid biooil product is obtained that
is so refined that the liquid product can be combined with crude
oil to make gasoline. In addition, it has been found that by
in-situ upgrading the biomass pyrolysis vapor to have less acidity,
one can attain a liquid biooil product which is easier to handle
and less corrosive in post-pyrolysis treatment. It has also been
found that in-situ upgrading of hot pyrolysis vapor is more
attractive and economical, as biooil with improved properties, such
as less oxygen and/or less acidity, is produced directly. This
makes the further upgrading into liquid transportation fuels more
cost effective due to less hydrogen being required. Energy is also
saved for pyrolysis vapor cooling and pyrolysis oil reheating.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] For a more complete understanding of the exemplary
embodiments of the present invention and the advantages thereof,
reference is now made to the following description in conjunction
with the accompanying drawings, which are briefly described as
follows.
[0012] FIG. 1 is a schematic of a process for in-situ upgrading of
pyrolysis vapor using a multi-layered catalyst bed, with multiple
layers of the different catalysts, according to an exemplary
embodiment.
[0013] FIG. 2 is a schematic of a process for in-situ upgrading of
pyrolysis vapor using cascaded catalyst reactors (or beds),
according to an exemplary embodiment.
[0014] FIG. 3 is a schematic of a process for in-situ upgrading of
pyrolysis vapor using an acid catalyst in the presence of alcohol,
according to an exemplary embodiment.
[0015] FIG. 4 is a schematic of a process for in-situ upgrading of
pyrolysis vapor using a water-gas shift reaction catalyst and a
hydrotreating catalyst, with multiple layers of the different
catalysts, according to an exemplary embodiment.
[0016] FIG. 5 is a schematic of a process for in-situ upgrading of
pyrolysis vapor using a water-gas shift reaction catalyst and a
hydrotreating catalyst, using cascaded catalyst reactors (or beds),
according to an exemplary embodiment.
[0017] FIG. 6 is a schematic of a process for in-situ upgrading of
pyrolysis vapor using a cracking catalyst, a water-gas shift
reaction catalyst, and a hydrotreating catalyst, with multiple
layers of the different catalysts, according to an exemplary
embodiment.
[0018] FIG. 7 is a schematic of a process for in-situ upgrading of
pyrolysis vapor using a cracking catalyst, a water-gas shift
reaction catalyst, and a hydrotreating catalyst, using cascaded
catalyst reactors (or beds), according to an exemplary
embodiment.
DETAILED DESCRIPTION
[0019] Illustrative embodiments of the invention are described
below. In the interest of clarity, not all features of an actual
implementation are described in this specification. One of ordinary
skill in the art will appreciate that in the development of any
such actual embodiment, numerous implementation-specific decisions
must be made to achieve the developers' specific goals, such as
compliance with system-related and business-related constraints,
which will vary from one implementation to another. Moreover, it
will be appreciated that such a development effort might be complex
and time-consuming, but would nevertheless be a routine undertaking
for those of ordinary skill in the art having the benefit of this
disclosure.
[0020] The present invention may be better understood by reading
the following description of non-limitative embodiments with
reference to the attached drawings wherein like parts of each of
the figures are identified by the same reference characters. The
words and phrases used herein should be understood and interpreted
to have a meaning consistent with the understanding of those words
and phrases by those skilled in the relevant art. No special
definition of a term or phrase, for example, a definition that is
different from the ordinary and customary meaning as understood by
those skilled in the art, is intended to be implied by consistent
usage of the term or phrase herein. To the extent that a term or
phrase is intended to have a special meaning, for example, a
meaning other than that understood by skilled artisans, such a
special definition will be expressly set forth in the specification
in a definitional manner that directly and unequivocally provides
the special definition for the term or phrase. Moreover, various
streams or conditions may be referred to with terms such as "hot,"
"cold," "cooled, "warm," etc., or other like terminology. Those
skilled in the art will recognize that such terms reflect
conditions relative to another process stream, not an absolute
measurement of any particular temperature.
[0021] The present application is directed to an improved biomass
pyrolysis process that performs in-situ upgrading of
pyrolysis-vapor using different catalysts. Specifically, a catalyst
bed with multi-layered catalysts or cascaded catalytic reactors
with different catalysts are implemented in a regular fast
pyrolysis unit. The biooil produced this way will have improved
properties, for instance, lower oxygen content and/or less acidity,
over biooils produced from regular fast pyrolysis. The present
application is also directed to systems for implementing such
processes.
[0022] Referring to FIG. 1, a process 100 for in-situ upgrading of
pyrolysis vapor using a multi-layered catalyst bed reactor 102 is
illustrated. A biomass stream 104 and a recycled off-gas stream 106
are fed into a fluid bed pyrolysis reactor 108. In certain
exemplary embodiments, the recycled off-gas stream 106 includes
nitrogen (N.sub.2). The recycled off gas stream 106 fluidizes the
bed in the pyrolysis reactor 108. In certain exemplary embodiments,
the biomass stream 104 includes wood sawdust, bark, yard waste,
waste lumber, agricultural wastes, peat, paper mill wastes,
cellulosic wastes, municipal solid waste, food processing wastes,
sewage sludge, and the like. In certain embodiments, the biomass
stream 104 can be dried prior to entering the fluid bed pyrolysis
reactor 108. In certain exemplary embodiments, the biomass stream
104 is dried to less than 10 wt % moisture content. In certain
exemplary embodiments, the biomass stream 104 is ground to form
small particles, for instance, less than 3 millimeters (mm) in its
shortest dimension.
[0023] The pyrolysis reactor 108 is any reactor type capable of
completing a pyrolysis reaction involving thermal decomposition of
the biomass stream 104 at short reaction times. The pyrolysis
reaction is sometimes called "fast", "flash", or "rapid" pyrolysis.
The reaction is conducted in a reactor type capable of high heat
transfer rates to small biomass particles, in order to achieve the
rapid increase in temperature of the particle that is necessary.
Suitable examples of pyrolysis reactors include, but are not
limited to, fluidized bed reactors, circulating fluidized bed
reactors, and transport reactors. In fluidized bed reactors and
circulating fluidized bed reactors, hot gases and solids are
brought into intimate contact with the biomass particles in the
biomass stream 104. In certain exemplary embodiments, the solids
are normally inert, for instance, silica or sand. In transport
reactors, either hot gas alone or a mixture of hot gas and solids
may be used. All reactors generally require a significant recycled
off-gas flow, usually from about 1 to about 10 times the weight of
biomass stream 104 being processed. If the pyrolysis reaction is
carried out in the absence of oxygen, for example, in a nitrogen
atmosphere, then the non-condensable gases formed have significant
contents of carbon monoxide, hydrogen, methane and other light
hydrocarbons or organics, which can be burned. The pyrolysis
reactor 108 is generally operated at conditions which promote
maximum yield of organic liquid. In certain exemplary embodiments,
the pyrolysis reactor 108 is operated at a temperature in the range
of from about 400 degrees Celsius (.degree. C.) to about
650.degree. C., a vapor residence time of less than about 2
seconds, and at substantially atmospheric pressure. Generally, the
pyrolysis reaction yields a pyrolysis vapor stream 110 that exits a
top 108a of the pyrolysis reactor 108.
[0024] Once the pyrolysis on the biomass stream 104 is complete,
the pyrolysis vapor stream 110 is often passed through separation
devices, such as filters or cyclones, in order to remove any
entrained solid particles, or char, 112a, 112b, resulting from the
pyrolysis reaction. In certain exemplary embodiments, the pyrolysis
vapor stream 110 enters a first cyclone reactor 114 to separate
pyrolysis vapors from entrained char. A pyrolysis vapor stream 116
exits the first cyclone reactor 114 and enters a second cyclone
reactor 118 to further separate pyrolysis vapors from entrained
char. A pyrolysis vapor stream 120 exits the second cyclone reactor
118 and is introduced at a top 102a of the multi-layered catalyst
bed reactor 102. In certain exemplary embodiments, the pyrolysis
vapor stream 120 is substantially free of particles so as not to
plug the catalyst bed reactor 102.
[0025] The catalyst bed reactor 102 includes multiple layers of the
different catalysts. The pyrolysis vapor stream 120 passes through
each catalyst bed, in sequence from the top 102a to a bottom 102b,
in the multi-layer catalyst bed reactor 102. The selection and
proper combination of different catalysts is important, as it
determines the performance of the catalytic treatment of the
pyrolysis vapor stream 120.
[0026] In certain exemplary embodiments, a top catalyst 102c would
be a zeolite type cracking catalyst, preferably HZSM-5, as this
catalyst can be operated at a temperature between about 370 and
about 410.degree. C., at atmospheric pressure. The cracking
catalyst will crack the hydrocarbon in the pyrolysis vapor stream
120. Suitable examples of other zeolite cracking catalysts for use
include, but are not limited to, REX, REY, and USY zeolites. Any
suitable temperature and pressure can be used, based upon the
degree of cracking desired. Some zeolite type catalysts, such
HZSM-5, are prone to coke or char formation on the catalyst. The
extent of the coking can be controlled by the relative space
velocity of the pyrolysis vapor stream in the catalyst bed. Other
cracking catalysts, for example those used in catalytic crackers
(for instance fluid catalytic cracking units), may be less prone to
coking relative to zeolites. Other types of catalysts, such as
alumina based catalysts, can be used as cracking catalysts and will
have lower coking tendencies.
[0027] In certain exemplary embodiments, a middle catalyst 102d
would be a high temperature water-gas-shift catalyst, for example,
a precious metal catalyst such as platinum (Pt)/mixed oxide, which
are good for operating in the temperature range of from about 350
to about 450.degree. C. The purpose of using a shift catalyst is to
convert the water and carbon monoxide (CO) in the pyrolysis vapor
stream 120 into hydrogen (H.sub.2) and carbon dioxide (CO.sub.2),
thus providing the hydrogen required by hydrodeoxygenation or
hydrotreating. The water-gas shift reaction catalysts generally
include a transition metal or transition metal oxide. In certain
exemplary embodiments, precious metal catalysts, such as platinum
in a mixed oxide, are utilized for operating in a temperature range
of from about 350 to about 450.degree. C. The hydrogen is then
available for the hydrotreating or hydrodeoxygenation. The relative
space velocity of the hot vapor stream through the bed can be
designed and controlled to produce the maximum amount of hydrogen.
The limiting factor will be the amount of carbon monoxide present
in the pyrolysis vapor stream. Since water-gas shift is an
equilibrium process, injection of additional hot water vapor before
this catalyst would drive the conversion of all of the carbon
monoxide into carbon dioxide and produce more hydrogen.
[0028] A third catalyst 102e would include a hydrotreating (or
hydrodeoxygenation) catalyst. Suitable examples of hydrotreating or
hydrodeoxygenation catalysts include, but are not limited to, any
known nickel molybdenum (NiMo), cobalt molybdenum (CoMo), or noble
metal catalyst supported on .gamma.-alumina. Generally, such
catalysts are commercially available. In certain exemplary
embodiments, the reaction is generally run at a temperature in the
range from about 350 to about 450.degree. C., at atmospheric
pressure. The hydrotreating removes the oxygen
containing-hydrocarbons in the pyrolysis vapor.
[0029] In certain exemplary embodiments, a solid acid catalyst
102f, such as sulfated zirconia, zeolite .beta., or Nafion-silicone
disoxide (SiO.sub.2) composite (SAC-13), can be added to the very
bottom 102b of the catalyst bed reactor 102 with an injection of an
alcohol stream 124 to perform an esterification process. The
alcohol stream 124 can include methanol or ethanol, and can be
injected into the catalyst 102f bed, catalyst bed reactor 102, or
pyrolysis vapor stream 120 to support the esterification reaction.
The purpose of using the catalyst 102f is to reduce the acidity of
pyrolysis vapor stream 120 by letting the carboxylic acid (e.g.,
acetic acid) in the pyrolysis vapor stream 120 react with the
alcohol stream 124 to form ester and water. An upgraded pyrolysis
vapor stream 130 is removed from the bottom 102b of the catalyst
bed reactor 102 and directed to a quench tower 134. The pyrolysis
vapor stream 130 is generally less acidic and safer for transport
through pipes and equipment.
[0030] The order in which the pyrolysis vapor stream 120 contacts
the foregoing catalysts can be any order. In certain exemplary
embodiments, the water-gas shift catalyst is generally contacted
prior to the hydrotreating catalyst so that the water-gas shift
reaction can produce hydrogen, which can be used in the
hydrotreating reaction, and thereby make the process more
efficient. In one embodiment, the cracking catalyst is contacted
first, followed by the water-gas shift catalyst, hydrotreating
catalyst, and then the acid catalyst. In another embodiment, the
water-gas shift catalyst is contacted first, followed by the
hydrotreating catalyst, the acid catalyst, and then the cracking
catalyst.
[0031] The pyrolysis vapor stream 130 is quenched and converted
into a liquid biooil product 140, and collected at a base 136 of
the quench tower 134. A portion 140a of the biooil product 140 is
collected in a biooil collection tank 144, while a portion 140b can
be pumped via pump 146 through a heat exchanger 148 to produce a
cooled biooil stream 150. In certain exemplary embodiments, the
cooled biooil stream 150 is reintroduced at a top 134a of the
quench tower 134 to quench the pyrolysis vapor stream 130.
[0032] In certain exemplary embodiments, a biooil vapor stream 154
from the quench tower 134 is directed to a condenser 156 to cool
and condense the biooil vapor stream 154 to produce a condensed
biooil stream 158 and a non-condensable gas stream 160. In certain
exemplary embodiments, the condensed biooil stream 158 is routed to
the biooil collection tank 144. The biooil collected in tank 144
generally has an oxygen content in the range of from about 30 to
about 40 percent (%) (dry, ash free basis) and a water content in
the range of from about 15 to about 25%, depending on the operating
temperatures of the quench tower and the condensers. The biooil
product is generally phase stable and which may separate from a
lighter density, more water rich product phase. Typical pH values
for the biooil product are in the range of from about 2 to about
5.
[0033] FIG. 2 illustrates a process 200 for in-situ upgrading of
pyrolysis vapor, according to another exemplary embodiment. The
process 200 for in-situ upgrading of pyrolysis vapor is the same as
that described above with regard to the process 100 for in-situ
upgrading of pyrolysis vapor, except as specifically stated below.
For the sake of brevity, the similarities will not be repeated
hereinbelow. The process 200 utilizes cascaded catalytic reactors,
each having a single type of catalyst therein.
[0034] Referring now to FIG. 2, the pyrolysis vapor stream 120 free
of particles exits the second cyclone reactor 118 and is passed
through a heat exchanger 202 to control the temperature of the
pyrolysis vapor stream 120 to produce a pyrolysis vapor stream 204.
The temperature of the pyrolysis vapor stream 120 is adjusted to
achieve optimal conditions for catalysis. The pyrolysis vapor
stream 204 is introduced into a first catalytic reactor 208. In
certain exemplary embodiments, the first catalytic reactor 208
includes a zeolite cracking catalyst therein. A pyrolysis vapor
stream 210 exits the first catalytic reactor 208 and is passed
through a heat exchanger 212 to control the temperature of the
pyrolysis vapor stream 210 to produce a pyrolysis vapor stream 214.
The temperature of the pyrolysis vapor stream 210 is adjusted to
achieve optimal conditions for catalysis.
[0035] The pyrolysis vapor stream 214 is introduced into a second
catalytic reactor 218. In certain exemplary embodiments, the second
catalytic reactor 218 includes a water-gas shift catalyst therein.
A pyrolysis vapor stream 220 exits the second catalytic reactor 218
and is passed through a heat exchanger 222 to control the
temperature of the pyrolysis vapor stream 220 to produce a
pyrolysis vapor stream 224. The temperature of the pyrolysis vapor
stream 220 is adjusted to achieve optimal conditions for
catalysis.
[0036] The pyrolysis vapor stream 224 is introduced into a third
catalytic reactor 228. In certain exemplary embodiments, the third
catalytic reactor 228 includes a hydrotreating catalyst therein. A
pyrolysis vapor stream 230 exits the third catalytic reactor 228
and is passed through a heat exchanger 232 to control the
temperature of the pyrolysis vapor stream 230 to produce a
pyrolysis vapor stream 234. The temperature of the pyrolysis vapor
stream 230 is adjusted to achieve optimal conditions for
catalysis.
[0037] The pyrolysis vapor stream 234 is introduced into a fourth
catalytic reactor 238. In certain exemplary embodiments, the fourth
catalytic reactor 238 includes an acid catalyst therein. The
alcohol stream 124 can be injected with the pyrolysis vapor stream
234 to perform the esterification process and lower the acidity of
the resulting upgraded pyrolysis vapor stream 240. The pyrolysis
vapor stream 240 exits the fourth catalytic reactor 238 and is
directed to the quench tower 134.
[0038] Generally, the processes of the present invention involves
thermal conversion of biomass by pyrolysis, i.e., in a pyrolysis
reactor. A greatly improved liquid, biooil product is obtained by
the present process as the pyrolysis vapor is upgraded. The
pyrolysis vapor is contacted with a cracking catalyst, a water-gas
shift reaction catalyst, a hydrotreating catalyst and an acid
catalyst. This particular selection of catalysts provides an
upgraded vapor that is converted into a liquid product by a means
such as by quenching, thus resulting in a biooil liquid so refined
that it can be combined with crude oil to give a useful gasoline
product. No additional refining is necessary. Further refining, of
course, can be conducted to fine tune the properties of the biooil
product, depending on the ultimate product desired.
[0039] The selection and proper combination of the different
catalysts allows for upgrading of the pyrolysis vapor, and thereby
provides the resulting refined biooil. The use of a cracking
catalyst, in combination with a hydrotreating catalyst and a
water-gas shift reaction catalyst, and an acid catalyst, can
provide one with a liquid biooil product having reduced oxygen and
water content as well as lowered acidity. In general, the pyrolysis
vapor can contact the different catalysts in any order desired. The
catalysts can be arranged in a multi-layer fashion, in separate
reactors, or in a combination of such.
[0040] Contacting the catalysts with the pyrolysis vapor stream 120
can be conducted in any suitable fashion. In certain embodiments,
the contacting is conducted in a single reactor where the catalysts
are situated in a multilayer fashion. The vapor contacts each
catalyst in order as situated in the multilayer fashion. In other
embodiments, the catalysts are arranged in separate reactors, with
the pyrolysis vapor being passed in sequence through each reactor.
Heat exchangers can be included in between the cascaded reactors to
heat or cool the pyrolysis vapor for the appropriate temperatures
required by various upgrading catalysts. In addition, it would
allow for easier sampling of the upgraded vapor for analysis after
each stage, thus allowing more control over the process. In such an
embodiment, the temperature and pressure for each reaction can be
better fine tuned to control the reaction. Also, guard beds can be
placed before each reactor to filter out unwanted materials, if so
desired.
[0041] FIG. 3 illustrates a process 300 for in-situ upgrading of
pyrolysis vapor using the acid catalyst, according to an exemplary
embodiment. The process 300 for in-situ upgrading of pyrolysis
vapor is the same as that described above with regard to the
process 100 for in-situ upgrading of pyrolysis vapor, except as
specifically stated below. For the sake of brevity, the
similarities will not be repeated hereinbelow. Referring now to
FIG. 3, the pyrolysis vapor stream 120 enters a catalyst bed
reactor 302. The catalyst bed reactor 302 includes a solid acid
catalyst bed 302f with an injection of alcohol stream 124 to
perform an esterification process. An upgraded pyrolysis vapor
stream 330 is removed from a bottom 302b of the catalyst bed
reactor 302 and directed to the quench tower 134. The pyrolysis
vapor stream 330 is generally less acidic and safer for transport
through pipes and equipment.
[0042] FIG. 4 illustrates a process 400 for in-situ upgrading of
pyrolysis vapor using a water-gas shift catalyst and a
hydrotreating (or hydrodeoxygenation) catalyst, according to an
exemplary embodiment. The process 400 for in-situ upgrading of
pyrolysis vapor is the same as that described above with regard to
the process 100 for in-situ upgrading of pyrolysis vapor, except as
specifically stated below. For the sake of brevity, the
similarities will not be repeated hereinbelow. Referring now to
FIG. 4, the pyrolysis vapor stream 120 enters a catalyst bed
reactor 402 having a top catalyst 402d and a bottom catalyst 402e.
The catalyst bed reactor 402 includes multiple layers of the
different catalysts. In certain exemplary embodiments, the top
catalyst 402d is a water-gas shift catalyst. In certain exemplary
embodiments, the bottom catalyst 402e is a hydrotreating catalyst.
The pyrolysis vapor stream 120 passes through each catalyst bed, in
sequence from a top 402a to a bottom 402b, in the multi-layer
catalyst bed reactor 402. In certain exemplary embodiments, the
water-gas shift catalyst is contacted first, followed by the
hydrotreating catalyst. An upgraded pyrolysis vapor stream 430 is
removed from the bottom 402b of the catalyst bed reactor 402 and
directed to the quench tower 134.
[0043] FIG. 5 illustrates a process 500 for in-situ upgrading of
pyrolysis vapor, according to another exemplary embodiment. The
process 500 for in-situ upgrading of pyrolysis vapor is the same as
that described above with regard to the process 400 for in-situ
upgrading of pyrolysis vapor, except as specifically stated below.
For the sake of brevity, the similarities will not be repeated
hereinbelow. The process 500 utilizes cascaded catalytic reactors,
each having a single type of catalyst therein.
[0044] Referring now to FIG. 5, the pyrolysis vapor stream 120 is
passed through a heat exchanger 512 to control the temperature of
the pyrolysis vapor stream 120 to produce a pyrolysis vapor stream
514. The temperature of the pyrolysis vapor stream 120 is adjusted
to achieve optimal conditions for catalysis. The pyrolysis vapor
stream 514 is introduced into a first catalytic reactor 518. In
certain exemplary embodiments, the first catalytic reactor 518
includes a water-gas shift catalyst therein. A pyrolysis vapor
stream 520 exits the first catalytic reactor 518 and is passed
through a heat exchanger 522 to control the temperature of the
pyrolysis vapor stream 520 to produce a pyrolysis vapor stream 524.
The temperature of the pyrolysis vapor stream 520 is adjusted to
achieve optimal conditions for catalysis.
[0045] The pyrolysis vapor stream 524 is introduced into a second
catalytic reactor 528. In certain exemplary embodiments, the second
catalytic reactor 528 includes a hydrotreating catalyst therein. A
pyrolysis vapor stream 530 exits the second catalytic reactor 528
and is directed to the quench tower 134. By upgrading the pyrolysis
vapor in accordance with the processes 400, 500, the overall
upgrading process is more thermally efficient. The heat loss due to
condensation of pyrolysis vapor and the reheating of biooil is
avoided. Furthermore, no hydrogen is needed, as hydrogen can be
provided internally by the water-gas-shift reaction. In addition,
the biooil produced from the quench tower 134 would have a lower
oxygen content, lower water content, and lower acidity.
[0046] FIG. 6 illustrates a process 600 for in-situ upgrading of
pyrolysis vapor using a cracking catalyst, a water-gas shift
catalyst, and a hydrotreating (or hydrodeoxygenation) catalyst,
according to an exemplary embodiment. The process 600 for in-situ
upgrading of pyrolysis vapor is the same as that described above
with regard to the process 100 for in-situ upgrading of pyrolysis
vapor, except as specifically stated below. For the sake of
brevity, the similarities will not be repeated hereinbelow.
Referring now to FIG. 6, the pyrolysis vapor stream 120 enters a
catalyst bed reactor 602 having a top catalyst 602c, a middle
catalyst 602d, and a bottom catalyst 602e. The catalyst bed reactor
602 includes multiple layers of the different catalysts. In certain
exemplary embodiments, the top catalyst 602c is a cracking
catalyst. In certain exemplary embodiments, the middle catalyst
602d is a water-gas shift catalyst. In certain exemplary
embodiments, the bottom catalyst 602e is a hydrotreating catalyst.
The pyrolysis vapor stream 120 passes through each catalyst bed, in
sequence from a top 602a to a bottom 602b, in the multi-layer
catalyst bed reactor 602. The order in which the pyrolysis vapor
stream 120 contacts the foregoing catalysts can be any order. In
certain exemplary embodiments, the water-gas shift catalyst is
generally contacted prior to the hydrotreating catalyst so that the
water-gas shift reaction can produce hydrogen, which can be used in
the hydrotreating reaction, and thereby make the process more
efficient. In one embodiment, the cracking catalyst is contacted
first, followed by the water-gas shift catalyst, and then the
hydrotreating catalyst. In another embodiment, the water-gas shift
catalyst is contacted first, followed by the hydrotreating
catalyst, and then the cracking catalyst. An upgraded pyrolysis
vapor stream 630 is removed from the bottom 602b of the catalyst
bed reactor 602 and directed to the quench tower 134.
[0047] FIG. 7 illustrates a process 700 for in-situ upgrading of
pyrolysis vapor, according to another exemplary embodiment. The
process 700 for in-situ upgrading of pyrolysis vapor is the same as
that described above with regard to the process 600 for in-situ
upgrading of pyrolysis vapor, except as specifically stated below.
For the sake of brevity, the similarities will not be repeated
hereinbelow. The process 700 utilizes cascaded catalytic reactors,
each having a single type of catalyst therein.
[0048] Referring now to FIG. 7, the pyrolysis vapor stream 120 is
passed through a heat exchanger 702 to control the temperature of
the pyrolysis vapor stream 120 to produce a pyrolysis vapor stream
704. The temperature of the pyrolysis vapor stream 120 is adjusted
to achieve optimal conditions for catalysis. The pyrolysis vapor
stream 704 is introduced into a first catalytic reactor 708. In
certain exemplary embodiments, the first catalytic reactor 708
includes a zeolite cracking catalyst therein. A pyrolysis vapor
stream 710 exits the first catalytic reactor 708 and is passed
through a heat exchanger 712 to control the temperature of the
pyrolysis vapor stream 710 to produce a pyrolysis vapor stream 714.
The temperature of the pyrolysis vapor stream 710 is adjusted to
achieve optimal conditions for catalysis.
[0049] The pyrolysis vapor stream 714 is introduced into a second
catalytic reactor 718. In certain exemplary embodiments, the second
catalytic reactor 718 includes a water-gas shift catalyst therein.
A pyrolysis vapor stream 720 exits the second catalytic reactor 718
and is passed through a heat exchanger 722 to control the
temperature of the pyrolysis vapor stream 720 to produce a
pyrolysis vapor stream 724. The temperature of the pyrolysis vapor
stream 720 is adjusted to achieve optimal conditions for
catalysis.
[0050] The pyrolysis vapor stream 724 is introduced into a third
catalytic reactor 728. In certain exemplary embodiments, the third
catalytic reactor 728 includes a hydrotreating catalyst therein. A
pyrolysis vapor stream 730 exits the third catalytic reactor 728
and is directed to the quench tower 134. By upgrading the pyrolysis
vapor in accordance with the processes 600, 700, the overall
upgrading process is more thermally efficient. The heat loss due to
condensation of pyrolysis vapor and the reheating of biooil is
avoided. Also, a liquid biooil product is obtained that is refined
such that the product can be combined with crude oil to produce
gasoline. Furthermore, no hydrogen is needed, as hydrogen can be
provided internally by the water-gas-shift reaction. In addition,
the biooil produced from the quench tower 134 would have a lower
oxygen content, lower water content, and lower acidity.
[0051] By upgrading pyrolysis vapor in accordance with the
processes of the present invention, the overall upgrading process
is more thermally efficient than conventional processes. Heat loss
due to condensation of pyrolysis vapor and reheating of biooil is
avoided. Furthermore, no hydrogen (H.sub.2) is needed, as hydrogen
can be provided internally by the water-gas-shift reactions. In
addition, the biooil produced from the quench tower has less
oxygen, less water, and fewer acids than biooils produced using
conventional processes, and therefore has an improved quality over
conventional biooils. By treating the pyrolysis vapor in accordance
with the present invention, a liquid biooil product can be obtained
that is already so refined that it can be combined directly, or
with minimal further refining, to crude oil to make a gasoline
product.
[0052] To facilitate a better understanding of the present
invention, the following examples of certain aspects of some
embodiments are given. In no way should the following examples be
read to limit, or define, the scope of the invention.
EXAMPLES
Example 1
[0053] The typical operating conditions for a multi-layer fixed-bed
reactor would be: [0054] Catalysts used: Top layer--HZSM-5
(cracking catalyst); [0055] 2nd layer--Pt supported on mixed oxide
(water-gas shift catalyst); [0056] 3rd layer--NiMo and CoMo
Supported on .gamma.-alumina (hydrotreating catalyst); [0057]
Bottom layer--Zeolite .beta. (acid catalyst). [0058] Pressure:
Atmospheric [0059] Temperature: 350-400.degree. C. [0060] Volume
Ratio: Determined by space velocities required; also considering
cost, generally [0061] Top layer: 2nd layer: 3rd layer: Bottom
layer=5:2:3:10 [0062] Expected Bio-oil Quality: [0063] Oxygen
content: <10 wt % [0064] Water content: <5 wt % [0065] pH:
5-6
Example 2
[0066] The typical operating conditions for an acid catalyst
fixed-bed reactor would be: [0067] Catalysts used: Zeolite .beta.
(acid catalyst). [0068] Pressure: Atmospheric [0069] Temperature:
350-400.degree. C. [0070] Expected Bio-oil Quality: [0071] pH:
5-6
Example 3
[0072] The typical operating conditions for a multi-layer fixed
-bed reactor would be: [0073] Catalysts used: Top layer--Pt
supported on mixed oxide (water-gas shift catalyst); [0074] 2nd
layer-NiMo and CoMo Supported on .gamma.-alumina (hydrotreating
catalyst); [0075] Pressure: Atmospheric [0076] Temperature:
350-400.degree. C. [0077] Expected Bio-oil Quality: [0078] Oxygen
content: <10 wt % [0079] Water content: <5 wt %
Example 4
[0080] The typical operating conditions for a multi-layer fixed
-bed reactor would be: [0081] Catalysts used: Top layer--HZSM-5
(cracking catalyst); [0082] 2nd layer--Pt supported on mixed oxide
(water-gas shift catalyst); [0083] 3rd layer-NiMo and CoMo
Supported on .gamma.-alumina (hydrotreating catalyst). [0084]
Pressure: Atmospheric [0085] Temperature: 350-400.degree. C. [0086]
Volume Ratio: Determined by space velocities required; also
considering cost, generally [0087] Top layer: 2nd layer: 3rd
layer=5:2:3 [0088] Expected Bio-oil Quality: [0089] Oxygen content:
<10 wt % [0090] Water content: <5 wt %
[0091] Therefore, the present invention is well adapted to attain
the ends and advantages mentioned as well as those that are
inherent therein. The particular embodiments disclosed above are
illustrative only, as the present invention may be modified and
practiced in different but equivalent manners apparent to those
skilled in the art having the benefit of the teachings herein.
While numerous changes may be made by those skilled in the art,
such changes are encompassed within the spirit of this invention as
defined by the appended claims. Furthermore, no limitations are
intended to the details of construction or design herein shown,
other than as described in the claims below. It is therefore
evident that the particular illustrative embodiments disclosed
above may be altered or modified and all such variations are
considered within the scope and spirit of the present invention.
The terms in the claims have their plain, ordinary meaning unless
otherwise explicitly and clearly defined by the patentee.
* * * * *