U.S. patent application number 13/106282 was filed with the patent office on 2011-11-17 for hydroprocessing of pyrolysis oil and its use as a fuel.
This patent application is currently assigned to EXXONMOBIL RESEARCH AND ENGINEERING COMPANY. Invention is credited to Karlton J. Hickey, William J. Novak, Richard J. Quann, Randolph J. Smiley.
Application Number | 20110277377 13/106282 |
Document ID | / |
Family ID | 44626550 |
Filed Date | 2011-11-17 |
United States Patent
Application |
20110277377 |
Kind Code |
A1 |
Novak; William J. ; et
al. |
November 17, 2011 |
HYDROPROCESSING OF PYROLYSIS OIL AND ITS USE AS A FUEL
Abstract
This invention provides low sulfur fuels, particularly low
sulfur bunker fuels, comprising hydroprocessed pyrolysis oil. The
hydroprocessed pyrolysis oil can be produced using a catalyst
suited to processing pyrolysis oils that may be relatively high in
water content and under relatively low severity conditions to limit
water formation, while making the hydroprocessed pyrolysis oil more
stable than prior to hydroprocessing. The pyrolysis oil can be
converted to a more stable hydroprocessed product, e.g., by
converting at least a majority of the aldehydes, ketones, and/or
carboxylic acids in the pyrolysis oil to more highly stable
compounds, such as alcohols. The hydroprocessed product can be
particularly suited as a blend component for producing a variety of
reduced sulfur fuels.
Inventors: |
Novak; William J.;
(Bedminster, NJ) ; Smiley; Randolph J.;
(Hellertown, PA) ; Quann; Richard J.; (Moorestown,
NJ) ; Hickey; Karlton J.; (Boothwyn, PA) |
Assignee: |
EXXONMOBIL RESEARCH AND ENGINEERING
COMPANY
Annandale
NJ
|
Family ID: |
44626550 |
Appl. No.: |
13/106282 |
Filed: |
May 12, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61395600 |
May 14, 2010 |
|
|
|
Current U.S.
Class: |
44/435 |
Current CPC
Class: |
Y02P 30/20 20151101;
C10G 2300/202 20130101; Y02E 50/13 20130101; Y02E 50/10 20130101;
C10L 1/026 20130101; C10G 2300/1011 20130101; C10G 2300/1059
20130101 |
Class at
Publication: |
44/435 |
International
Class: |
C10L 1/00 20060101
C10L001/00 |
Claims
1. A process for producing a reduced sulfur fuel, comprising:
hydroprocessing pyrolysis oil in the presence of a
non-aluminum-containing support catalyst and hydrogen at a hydrogen
to pyrolysis oil ratio of not greater than about 1000 SCF/bbl
(about 170 Nm.sup.3/m.sup.3) to produce a hydroprocessed product;
and combining at least a portion of the hydroprocessed product with
a base fuel in which the base fuel has a sulfur content in excess
of that of the hydroprocessed product to produce the reduced sulfur
fuel.
2. The process of claim 1, wherein the hydrocarbon feedstock
comprises biomass.
3. The process of claim 1, wherein the non-aluminum-containing
support catalyst includes at least one metal from Groups 8-10 of
the Periodic Table of Elements.
4. The process of claim 1, wherein the non-aluminum-containing
support comprises a carbon support or a silica support.
5. The process of claim 4, wherein the non-aluminum-containing
support catalyst comprises at least one of palladium and
platinum.
6. The process of claim 1, wherein the pyrolysis oil is comprised
of one or more of aldehydes, ketones, and carboxylic acids.
7. The process of claim 1, wherein the base fuel includes at least
one gas oil, heavy fuel oil, or resid oil component.
8. The process of claim 1, wherein the hydroprocessed product
comprises at least 10 wt % non-aromatic alcohols, based on total
weight of the hydroprocessed product.
9. The process of claim 1, wherein the reduced sulfur fuel
comprises a diesel fuel, a home heating oil, an industrial heater
or boiler fuel, a marine fuel, or a combination thereof.
10. The process of claim 1, wherein the pyrolysis oil is a liquid
fraction of a pyrolysis product.
11. A process for producing a reduced sulfur fuel, comprising:
pyrolyzing a hydrocarbon feedstock to produce a pyrolysis oil;
hydroprocessing the pyrolysis oil in the presence of a
non-aluminum-containing support catalyst and hydrogen at a hydrogen
to pyrolysis oil ratio of not greater than about 1000 SCF/bbl
(about 170 Nm.sup.3/m.sup.3) to produce a hydroprocessed product;
and combining at least a portion of the hydroprocessed product with
a base fuel in which the base fuel has a sulfur content in excess
of that of the hydroprocessed product to produce the reduced sulfur
fuel.
12. The process of claim 11, wherein the hydrocarbon feedstock
comprises biomass.
13. The process of claim 11, wherein the non-aluminum-containing
support catalyst includes at least one metal from Groups 8-10 of
the Periodic Table of Elements.
14. The process of claim 11, wherein the non-aluminum-containing
support comprises a carbon support or a silica support.
15. The process of claim 14, wherein the non-aluminum-containing
support catalyst comprises at least one of palladium and
platinum.
16. The process of claim 11, wherein the pyrolysis oil is comprised
of one or more of aldehydes, ketones, and carboxylic acids.
17. The process of claim 11, wherein the base fuel includes at
least one gas oil, heavy fuel oil, or resid oil component.
18. The process of claim 11, wherein the hydroprocessed product
comprises at least 10 wt % non-aromatic alcohols, based on total
weight of the hydroprocessed product.
19. The process of claim 11, wherein the reduced sulfur fuel
comprises a diesel fuel, a home heating oil, an industrial heater
or boiler fuel, a marine fuel, or a combination thereof.
20. The process of claim 11, wherein the pyrolysis oil is a liquid
fraction of a pyrolysis product.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This Application claims the benefit of Provisional U.S.
Application No. 61/395,600, filed May 14, 2010, the contents of
which are hereby incorporated by reference herein.
FIELD OF THE INVENTION
[0002] This invention is directed to the hydroprocessing of
pyrolysis oils. In particular, this invention is directed to the
production of fuels from hydroprocessed pyrolysis oils.
BACKGROUND OF THE INVENTION
[0003] Pyrolysis oil, the liquid product of a particular
hydrocarbon heat treatment process, is known to have limited use as
a low grade or heavy fuel composition. The type of fuel use is
limited as a consequence of the relatively low quality fuel
characteristics that are common to pyrolysis oils. For example,
pyrolysis oils can contain undesirable amounts of water, which can
have a negative impact on catalysts used to upgrade fuel base or
blend stock components. Pyrolysis oils are also typically
relatively high in oxygen content, which limits their use in higher
quality diesel, jet, or gasoline fuels. In addition, typical
pyrolysis oils contain significant amounts of relatively unstable
compounds such as aldehydes, ketones and carboxylic acids, which
can have adverse effects on the oil composition over a period of
time.
[0004] A variety of hydroprocessing steps have been proposed to
treat pyrolysis oil to increase the fuel quality of the oil. The
proposed steps, however, are generally quite complex and
costly.
[0005] U.S. Patent Application Publication No. 2009/0253948
discloses a process for producing naphtha, aviation, and/or diesel
fuel, blending components, or related products from pyrolysis oil.
The pyrolysis oil is treated in a partial deoxygenation zone
generating a partially deoxygenated stream. Water, gases, and light
ends are removed, and the remainder of the partially deoxygenated
stream is further treated in a full deoxygenation zone to produce a
deoxygenated product stream. The deoxygenated product stream
comprises hydrocarbon compounds that, when fractionated, are useful
as gasoline and naphtha, aviation fuel, or as additives to, or
blending components of, one or both products. The product stream
can also be upgraded to produce a diesel fuel, blending component,
or additive. Furthermore, the product stream can serve as a source
of chemicals or chemical feedstocks.
[0006] U.S. Pat. No. 7,425,657 discloses a method of
hydrodeoxygenation of pyrolysis or bio-oil. The bio-oil and
hydrogen are reacted over a catalyst comprising Pd at a temperature
of more than 200.degree. C. Typically, the method is conducted in
the presence of water; with the bio-oil comprising 5-50 mass %
water. The bio-oil can be a single-phase or multi-phase liquid. In
preferred embodiments, water is removed during the step of reacting
the bio-oil and hydrogen over a catalyst. The method is further
characterized by a bio-oil deoxygenation of at least 50% and/or a
yield of liquid oil of at least 60%. The bio-oil comprises acetic
acid, and at least 30% of the acetic acid in the bio-oil is
converted to ethanol during the process.
[0007] U.S. Pat. No. 4,308,411 discloses a process for converting a
pyrolysis product of a cellulosic fraction derived from municipal
solid waste into a hydrocarbon. The solid waste is separated into
an inorganic fraction and an organic fraction. The organic fraction
is comminuted to a particle size of less than 8 mesh and dried
preferably to a moisture content of less than about 20%. The dried
organic fraction is then pyrolyzed in the presence of an inert
carrier gas, i.e., a carrier gas which is nondeleteriously reactive
with the pyrolysis products, and a heat source, for example a
carbon containing residue of pyrolysis of the organic fraction of
solid waste or a particulate inorganic solid heat source, which may
be formed from the decarbonization of said carbon-containing
residue of pyrolysis. The inorganic heat source that may be the
carbon-containing solid residue of pyrolysis or a decarbonized
inorganic solid derived therefrom is separated, along with any
solid carbon-containing residue, from the "pyrovapor." The
"pyrovapor" is deoxygenated after separation from the
carbon-containing solid residue of pyrolysis and/or the inorganic
heat source by contacting with a crystalline aluminosilicate
zeolite catalyst to convert the oxygenated hydrocarbons into
hydrocarbon product. The hydrocarbon product is gasoline.
[0008] If pyrolysis oils are to be viable as fuels, negative
characteristics associated with the oils, such as high water
content, high oxygen content, and stability of components within
the oils need to be further addressed. As the technology currently
stands, only highly complex, intensive treatment processes have
been suggested for treating pyrolysis oils, so that such oils can
be used as viable high quality fuels.
SUMMARY OF THE INVENTION
[0009] One aspect of the invention relates to a process for
producing a reduced sulfur fuel, comprising: hydroprocessing
pyrolysis oil in the presence of a non-aluminum support catalyst
and hydrogen at a hydrogen to pyrolysis oil ratio of not greater
than about 1000 SCF/bbl (about 170 Nm.sup.3/m.sup.3) to produce a
hydroprocessed product; and combining at least a portion of the
hydroprocessed product with a base fuel in which the base fuel has
a sulfur content in excess of that of the hydroprocessed product to
produce the reduced sulfur fuel.
[0010] Another aspect of the invention relates to a process for
producing a reduced sulfur fuel, comprising: pyrolyzing a
hydrocarbon feedstock to produce a pyrolysis oil; hydroprocessing
the pyrolysis oil in the presence of a non-aluminum support
catalyst and hydrogen at a hydrogen to pyrolysis oil ratio of not
greater than about 1000 SCF/bbl (about 170 Nm.sup.3/m.sup.3) to
produce a hydroprocessed product; and combining at least a portion
of the hydroprocessed product with a base fuel in which the base
fuel has a sulfur content in excess of that of the hydroprocessed
product to produce the reduced sulfur fuel.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Introduction
[0011] The present invention relates to processes for providing
reduced sulfur fuels. The low sulfur fuels are preferably produced
as a blend that includes a hydroprocessed pyrolysis oil product and
a base fuel in which the base fuel has a higher sulfur content than
that of the hydroprocessed pyrolysis oil product. In this manner, a
pyrolysis oil can be hydroprocessed to reduce its sulfur content,
so that a higher sulfur hydrocarbon, e.g., a base fuel that is
off-spec for high sulfur content, can be used as an on-spec fuel
blend composition.
[0012] Due to the innate chemistry of pyrolysis oils, e.g.,
typically a relatively high water content, the hydroprocessed
pyrolysis oil product can advantageously be produced using a
catalyst that can tolerate that chemistry (e.g., water content).
Additionally or alternately, the pyrolysis oil can be
hydroprocessed under relatively low severity conditions, e.g., to
limit additional water formation and/or to make the pyrolysis oil
more stable (i.e., to reduce the content of higher reactivity
compounds, preferably in favor of lower reactivity compounds). For
instance, the pyrolysis oil can be converted to a more stable
product by converting at least a majority of the aldehydes,
ketones, and/or carboxylic acids in the pyrolysis oil to more
highly stable partially deoxygenated compounds (e.g., alcohols)
and/or completely deoxygenated hydrocarbons. The hydroprocessed
pyrolysis oil product can also be relatively very low in sulfur
content and can thus be particularly suited as a blend component
for a variety of fuels, or in certain rare circumstances as a fuel
composition by itself. Examples of preferred fuels for blending
with the hydroprocessed pyrolysis oil product can include, but are
not limited to, distillate fuels that include diesel fuel, home
heating oil, industrial heating and boiler oil, marine fuels such
as bunker fuel, and the like, and combinations thereof.
Pyrolysis Oil
[0013] In general, pyrolysis is a thermal degradation process in
which large hydrocarbon molecules are broken or cracked into
smaller molecules in the presence of little if any (e.g.,
substantially no) reactive gas component such as oxygen. A wide
variety of hydrocarbon materials can be pyrolyzed to produce vapor,
liquid, and often solid hydrocarbon materials. The portion of the
pyrolysis product that is liquid at about 25.degree. C. and about
101 kPaa (about 14.7 psia, about 1.0 atm) absolute pressure, is
also referred to herein as pyrolysis oil. According to the present
invention, the pyrolysis oil can be hydroprocessed under
predetermined (effective hydroprocessing) conditions to produce a
hydroprocessed product, and optionally but preferably at least a
portion of the product can be combined or blended with higher
sulfur hydrocarbons, e.g., an off-spec high sulfur content base
fuel, to produce a lower sulfur fuel, such as an on-spec sulfur
content fuel composition.
[0014] A wide range of feedstocks of various types, sizes, and
moisture contents can be pyrolyzed to produce a pyrolysis oil that
can be processed according to the present invention. Feedstocks
that can be used in the pyrolysis step can comprise any hydrocarbon
that can be thermally decomposed or transformed. In a preferred
embodiment, the feedstock can comprise biomass, preferably at least
10 wt %, for example at least 30 wt %, at least 50 wt %, at least
70 wt %, or at least 90 wt % biomass, based on total weight of
feedstock processed/supplied to the thermal/pyrolysis reactor.
[0015] The term "biomass," for the purposes of this invention, is
considered any material not derived from fossil/mineral resources
and comprising at least carbon, hydrogen, and oxygen. Examples of
biomass can include, but are not limited to, plant and
plant-derived material, vegetation, agricultural waste, forestry
waste, wood waste, paper waste, animal-derived waste,
poultry-derived waste municipal solid waste, cellulose,
carbohydrates or derivates thereof, charcoal, and the like, and
combinations/mixtures thereof. The feedstock can additionally or
alternately comprise pyrolyzable components other than biomass,
such as fossil/mineral fuels (e.g., coal, petroleum, crude
oil-derived fuels, shale oil-derived fuels, and the like, and
combinations/mixtures thereof).
[0016] Further examples of biomass that can additionally or
alternately be present as feedstock components can include, but are
not limited to, timber harvesting residues, softwood chips,
hardwood chips, tree branches, tree stumps, leaves, bark, sawdust,
off-spec paper pulp, corn, corn cob, corn stover, wheat straw, rice
straw, sugarcane bagasse, switchgrass, miscanthus, animal manure,
municipal garbage, municipal sewage, commercial waste, grape
pumice, almond shells, pecan shells, coconut shells, coffee
grounds, grass pellets, hay pellets, wood pellets, cardboard,
paper, plastic, cloth, and the like, and combinations/mixtures
thereof.
[0017] The biomass to be pyrolyzed can optionally but preferably be
ground prior to pyrolyzing. For example, the biomass can be ground
in a mill until a desired particle size is achieved. In one
embodiment, the particle size of the biomass to be pyrolyzed is
sufficiently ground to pass through a 30 mm screen, for example
through a 20 mm screen, through a 10 mm screen, through a 5 mm
screen, or through a 1 mm screen.
[0018] Pyrolysis can preferably be carried out in a relatively
inert atmosphere, which means that there are few if any (e.g.,
substantially no) reactive components to react with the pyrolysis
feed material. Such reactive components can include hydrocarbon
reactive gases, such as reactive oxygen compounds, sulfur
compounds, and various reactive hydrogen compounds. Preferably,
pyrolysis can be carried out in an environment (e.g., in the
pyrolysis reactor) having a hydrocarbon reactive gas (e.g., oxygen,
sulfur, and/or hydrogen) content of not greater than about 10 vol
%, for example not greater than about 5 vol %, not greater than
about 1 vol %, or not greater than about 0.1 vol %. In a continuous
process, this reactive gas content can be based on total volume of
gas, e.g., fluidizing gas, supplied to the pyrolysis reactor during
continuous operation.
[0019] In one embodiment where reactive oxygen (i.e., oxygen that
is not covalently bonded to pyrolysis hydrocarbon feedstock) is
present in the hydrocarbon reactive gas(es), it can advantageously
be present in an amount less that the stoichiometric amount
required for complete combustion. Additionally or alternately,
pyrolysis can be carried out in an environment (e.g., in the
pyrolysis reactor) having an oxygen content of less than about 40%,
less than about 30%, less than about 20%, less than about 10%, less
than about 5%, less than about 1%, less than about 0.5%, less than
about 0.1%, or less than about 0.01% of the stoichiometric amount
of oxygen required for complete combustion of the feedstock.
Further additionally or alternately, pyrolysis can be carried out
in the absence of (added) reactive oxygen.
[0020] Pyrolysis conditions can preferably include those that
reduce and/or minimize non-condensable gas formation and/or
solid/char formation. Additionally or alternately, the pyrolysis
conditions can preferably include those that lead to condensable
gas and/or liquid formation. See, for example, Czernik and
Bridgwater, Energy & Fuels, 18:590-598, 2004; see also Mohan et
al., Energy & Fuels, 20:848-889, 2006.
[0021] In one embodiment, pyrolyzed product exits the pyrolysis
reactor as a vapor, preferably passing through a filter to separate
solids from the more desirable portion of the product. In this
embodiment, the filtered vapors can then be condensed to form one
or more liquid pyrolysis products.
[0022] Condensation can be carried out using any equipment suitable
for such purpose, e.g., a condensation train to collect the desired
products. The condensation train can comprise at least one chilled
water condenser, at least one electrostatic precipitator, at least
one coalescence filter, or a combination thereof.
[0023] Pyrolysis temperature should be high enough to convert a
sufficient quantity of feed to desired product, but not so high to
produce undesirably high quantities of non-condensable gas and/or
solid products. In a preferred embodiment, feed can be pyrolyzed at
a temperature from about 200.degree. C. to about 600.degree. C.,
for example from about 300.degree. C. to about 600.degree. C. or
from about 400.degree. C. to about 500.degree. C.
[0024] Pyrolysis pressure should be within a range that reduces
and/or minimizes formation of non-condensable gas and/or solid
products. The pressure can range from about 0 psig (about 0 MPag)
to about 1000 psig (about 6.9 MPag), for example from about 5 psig
(about 35 kPag) to about 500 psi (about 3.5 MPag) or from about 10
psig (about 69 kPag) to about 200 psig (about 1.4 MPag).
[0025] Pyrolysis can advantageously be carried out for a period of
time that enables a substantial or desired quantity of feed to be
converted into condensable vapor and/or liquid products. This time
window can range widely and can be rather broad, depending upon
pressure, temperature, type of reactor used, and other
considerations. For example, pyrolysis conditions can be
implemented for a period of time from about 0.1 seconds to about 24
hours, for example from about 0.1 seconds to about 1 hour, from
about 0.5 seconds to about 4 hours, from about 1 second to about 6
hours, from about 0.1 seconds to about 6 hours, from about 0.5
seconds to about 1 hour, from about 1 second to about 4 hours, or
from about 1 second to about 1 hour. If only for sheer economic
reasons, shorter times can be particularly advantageous, such as
from about 0.1 seconds to about 1 minute, from about 0.1 seconds to
about 30 seconds, from about 0.1 seconds to about 10 seconds, from
about 0.5 seconds to about 1 minute, from about 0.5 seconds to
about 30 seconds, from about 0.5 seconds to about 10 seconds, from
about 1 second to about 1 minute, from about 1 second to about 30
seconds, or from about 1 second to about 10 seconds.
[0026] In some embodiments, fast pyrolysis can be used. Fast
pyrolysis is a relatively high-temperature process in which
feedstock is relatively rapidly heated, in some embodiments in the
absence of oxygen. The feedstock can decompose to generate
predominantly vapor and solid (i.e., char) products. The vapor
product can preferably be cooled and condensed to form one or more
liquid products. Multiple steps of heating and cooling can be
carried out to produce intermediate pyrolysis liquid products. Fast
pyrolysis processes can produce from about 60 wt % to about 75 wt %
condensable gas and liquid products, from about 15 wt % to about 25
wt % solid char, and from about 10 w t% to about 20 wt %
non-condensable gas products, but these percentages can vary
greatly depending on the particular composition of the
feedstock.
[0027] Additionally or alternately, slow pyrolysis can be used. In
slow pyrolysis, the feedstock can be heated to not greater than
about 600.degree. C. for a period ranging from about 1 minute to
about 24 hours, for example from about 1 minute to about 60
minutes. Vapor product typically does not escape as rapidly in slow
pyrolysis as it does in fast pyrolysis. Thus, vapor products may
react more with each other as solid char and any liquid are being
formed. As the name would imply, rate of heating in slow pyrolysis
is typically slower than that used in fast pyrolysis. In slow
pyrolysis, a feedstock can be held at constant temperature or can
be relatively slowly heated. Vapors can be removed (e.g.,
continuously) as they are formed.
[0028] Further additionally or alternately, vacuum pyrolysis can be
used. In vacuum pyrolysis, the feedstock can be heated at less than
atmospheric pressure (less than about 0 kPag, or less than about
100 kPaa). Vacuum conditions can be used to decrease the boiling
point and/or to avoid, reduce, and/or minimize adverse chemical
reactions.
[0029] As mentioned above, pyrolysis product can contain water. As
an example, condensed pyrolysis product can contain from about 10
wt % to about 30 wt % water. Optionally but preferably, the water
can be removed prior to hydroprocessing using any appropriate
means, such as by flashing, decanting, distillation, membrane
separation, or the like, or any combination thereof. Thus
preferably, prior to hydroprocessing, water can be removed from
(water content can be reduced in) the pyrolysis product to produce
a pyrolysis oil hydroprocessing feedstock having not greater than
about 20 wt %, preferably not greater than about 10 wt %, for
example not greater than about 5 wt % water or not greater than
about 3 wt % water, based on total weight of the pyrolysis oil
hydroprocessing feedstock.
[0030] The pyrolysis oil used as feedstock for hydroprocessing can
unfortunately contain components that can be relatively unstable
over time. Such components can include, but are not necessarily
limited to, one or more of aldehydes, ketones, and carboxylic
acids.
[0031] In one embodiment, the pyrolysis oil hydroprocessing
feedstock can comprise at least about 1.0 wt % aldehydes, for
example at least about 1.5 wt % aldehydes, from about 1.5 wt % to
about 20 wt % aldehydes, or from about 2 wt % to about 15 wt %
aldehydes, based on total weight of the pyrolysis oil
hydroprocessing feedstock.
[0032] Additionally or alternately, the pyrolysis oil
hydroprocessing feedstock can comprise at least about 0.8 wt %
ketones, for example at least about 1 wt % ketones, from about 1 wt
% to about 10 wt % ketones, or from about 1.5 wt % to about 8 wt %
ketones, based on total weight of the pyrolysis oil hydroprocessing
feedstock.
[0033] Further additionally or alternately, the pyrolysis oil
hydroprocessing feedstock can comprise at least about 1.2 wt %
carboxylic acids, for example at least about 1.5 wt % carboxylic
acids, from about 1.5 wt % to about 25 wt % carboxylic acids, or
from about 2 wt % to about 20 wt % carboxylic acids, based on total
weight of the pyrolysis oil hydroprocessing feedstock.
Hydroprocessing Catalyst and Conditions
[0034] Hydroprocessing refers to processes or treatments that
expose at least a portion of a feedstock (in this case, the
pyrolysis product) to hydrogen in the presence of a hydroprocessing
catalyst to facilitate the reaction. Such processes can include,
but are not limited to, hydrodeoxygenation, hydrodenitrogenation,
hydrodesulfurization, hydrotreating, hydrocracking,
hydroisomerization, hydrodewaxing, and the like, and combinations
thereof. For examples of such processes, see U.S. Pat. Nos.
7,513,989, 7,435,335, 7,288,182, 7,288,181, 7,244,352 and
7,220,352, the relevant contents of which are hereby incorporated
by reference. Specifically with regard to the pyrolysis oil,
hydroprocessing can primarily involve the conversion of
oxygen-containing hydrocarbons to non-aromatic alcohols and/or
paraffins.
[0035] Pyrolysis oil can be hydroprocessed according to this
invention to produce a hydroprocessed product reduced in one or
more of aldehyde, ketone, and carboxylic acid content and
optionally but preferably increased in alcohol content. In a
particularly preferred embodiment, the pyrolysis product can be
reduced in each of aldehyde, ketone, and carboxylic acid content
and can be simultaneously increased in alcohol content.
[0036] Hydroprocessing catalysts suitable for use with a pyrolysis
oil-based feedstock according to the present invention can
preferably be able to tolerate at least a relatively low level
moisture content within the hydroprocessing environment or reaction
vessel, as there will generally be some amount of water included
with the pyrolysis oil, and additional water can form as a
byproduct during hydroprocessing.
[0037] Thus, in an effort to maintain catalytic activity and/or
catalyst life, the hydroprocessing catalyst and hydroprocessing
conditions can advantageously be maintained to limit/minimize water
formation during hydrolysis, while reducing at least one of
aldehyde, ketone, and carboxylic acid content in the hydroprocessed
pyrolysis oil product. Preferably, water formation can be
limited/minimized during hydroprocessing, while a majority (i.e.,
at least 50%) of the combined aldehyde, ketone, and carboxylic acid
components (e.g., as measured by the ratio of the
pre-hydroprocessing collective content to the post-processing
collective content) are converted, e.g., to alcohol components.
[0038] Hydroprocessing catalysts whose support(s) contain
substantially no aluminum (usually, but not necessarily, in oxide
form) can be preferred. For instance, non-aluminum-containing
supported catalysts can include at least one metal from Groups 8-10
of the Periodic Table of the Elements, designated according to the
IUPAC System. Examples of such metals can include, but are not
limited to, iron, ruthenium, osmium, cobalt, rhodium, iridium,
nickel, palladium, platinum, and combinations thereof. In a
particularly preferred embodiment, palladium and/or platinum is
present.
[0039] In the aforementioned hydroprocessing catalysts, the total
content of metals from Groups 8-10 can be at least about 0.1 wt %,
for example at least about 0.3 wt %, at least about 0.5 wt %, at
least about 1.0 wt %, at least about 2.0 wt %, or at least about
3.0 wt %. Additionally or alternately, the total content of metals
from Groups 8-10 can be about 40 wt % or less, for example about 30
wt % or less, about 25 wt % or less, about 20 wt % or less, about
15 wt % or less, about 10 wt % or less, or about 5.0 wt % or
less.
[0040] Hydroprocessing catalyst support materials can include, but
are not limited to, carbon (e.g., relatively high surface area
graphitized carbon, graphite, activated carbon, or the like, or a
combination thereof) and silica supports, with a preference for
support materials that are porous particulate solids and that
contain substantially no aluminum (alumina). Examples of carbon and
silica supports are described in U.S. Pat. No. 5,149,680, the
relevant contents of which are hereby incorporated by
reference.
[0041] When the catalyst comprises a carbon support material, the
support can advantageously have a relatively high BET surface area,
for example at least about 100 m.sup.2/g, at least about 200
m.sup.2/g, or at least about 300 m.sup.2/g. Additionally or
alternately, the BET surface area is typically not greater than
about 1000 m.sup.2/g, for example not greater than about 750
m.sup.2/g.
[0042] A preferred carbon support, such as an activated carbon
support, can be prepared by heat treating a carbon-containing
starting material, which can comprise/be any suitable carbon
material, such as an oleophilic graphite, a carbon black, or the
like.
[0043] Additionally or alternately, the carbon support material can
be at least partially oxidized, for example at a temperature from
about 300.degree. C. to about 1200.degree. C. for an appropriate
period of time to sufficiently oxidize the support material, prior
to use. In such an embodiment, the carbon support can be heated,
e.g., in an inert atmosphere at a temperature from about
900.degree. C. to about 3300.degree. C., and the heated carbon can
be oxidized, e.g., at a temperature from about 300.degree. C. to
about 1200.degree. C. Further in such an embodiment, the oxidized
material can optionally be heated, e.g., in an inert atmosphere
(such as nitrogen) at a temperature from about 900.degree. C. to
about 3000.degree. C.
[0044] Examples of oxidizing agents can include, but are not
limited to, steam, carbon dioxide, gases containing molecular
oxygen (e.g., air), or the like, or a combination thereof. In one
embodiment, oxidation can be carried out to give a carbon weight
loss of at least about 10 wt %, for example at least about 15 wt %,
based on weight of carbon subjected to the oxidation step.
Additionally or alternately, the carbon weight loss due to such
oxidation can be not greater than about 40 wt %, for example not
greater than about 25 wt %, of the carbon subjected to the
oxidation step. The rate of supply of oxidizing agent can be such
that the desired weight loss takes place over at least about 2
hours, for example over at least about 4 hours.
[0045] Preferred silica supports are those having a relatively high
surface area, for example greater than about 50 m.sup.2/g, greater
than about 75 m.sup.2/g, or greater than about 100 m.sup.2/g.
[0046] In the hydroprocessing reaction, it can be preferred to
limit the amount of hydrogen used in the process, e.g., to limit
any water that can be formed as a co-product. In one embodiment,
hydroprocessing can be carried out at a hydrogen to pyrolysis oil
treat gas ratio of not greater than about 1000 SCF/bbl (about 170
Nm.sup.3/m.sup.3), for example not greater than about 900 SCF/bbl
(about 150 Nm.sup.3/m.sup.3) or not greater than about 800 SCF/bbl
(about 140 Nm.sup.3/m.sup.3).
[0047] Hydroprocessing can be carried out over a wide range of
pressures, e.g., from about 3.4 MPaa (about 500 psia) to about 21
MPaa (about 3000 psia), from about 3.4 MPaa (about 500 psia) to
about 14 MPaa (about 2000 psia), from about 3.4 MPaa (about 500
psia) to about 12 MPaa (about 1800 psia), from about 3.4 MPaa
(about 500 psia) to about 9.0 MPaa (about 1300 psia), or from about
3.4 MPaa (about 500 psia) to about 6.2 MPaa (about 900 psia).
[0048] Hydroprocessing can also be carried out over a wide range of
temperatures, for example from about 200.degree. C. to about
500.degree. C., from about 200.degree. C. to about 400.degree. C.,
or from about 300.degree. C. to about 375.degree. C.
[0049] Space velocity through the reaction vessel in which
hydroprocessing is carried out should be high enough to avoid
over-reacting through high residence times. In one embodiment,
hydroprocessing can be carried out at a liquid hourly space
velocity (LHSV) of at least about 0.1 hr.sup.-1, for example at
least about 0.5 hr.sup.-1, at least about 1.0 hr.sup.-1, or at
least about 1.5 hr.sup.-1. Additionally or alternately, the LHSV
can be about 10 hr.sup.-1 or less, for example about 5.0 hr.sup.-1
or less, about 3.0 hr.sup.-1 or less, about 2.0 hr.sup.-1 or less,
or about 1.5 hr.sup.-1 or less.
Hydroprocessed Product
[0050] The hydroprocessed product produced according to the present
invention can advantageously be reduced in one or more of aldehyde,
ketone, and carboxylic acid content and optionally but preferably
can be increased in alcohol content. In a particularly preferred
embodiment, the pyrolysis product can be reduced in each of
aldehyde, ketone, and carboxylic acid content and can be
simultaneously increased in alcohol content.
[0051] In one embodiment, the hydroprocessed product can comprise
less than about 1.5 wt % aldehydes, for example less than about 1
wt % aldehydes or less than about 0.5 wt % aldehydes, based on
total weight of the hydroprocessed product. Additionally or
alternately, the hydroprocessed product can comprise less than
about 1 wt % ketones, for example less than about 0.5 wt % ketones
or less than about 0.1 wt % ketones, based on total weight of the
hydroprocessed product. Further additionally or alternately, the
hydroprocessed product can comprise less than about 1.5 wt %
carboxylic acids, for example less than about 1 wt % carboxylic
acids or less than about 0.5 wt % carboxylic acids, based on total
weight of the hydroprocessed product. Still further additionally or
alternately, the hydroprocessed product can comprise at least about
10 wt % non-aromatic alcohols, for example at least about 15 wt %
non-aromatic alcohols, at least about 20 wt % non-aromatic
alcohols, or at least about 25 wt % non-aromatic alcohols, based on
total weight of the hydroprocessed product.
[0052] The hydroprocessed product can also advantageously be
relatively low in sulfur content, for example comprising less than
about 2.0 wt % sulfur, less than about 1.0 wt % sulfur, less than
about 5000 wppm sulfur, less than about 2000 wppm sulfur, less than
about 1000 wppm sulfur, less than about 500 wppm sulfur, less than
about 200 wppm sulfur, less than about 100 wppm sulfur, less than
about 50 wppm sulfur, less than about 30 wppm sulfur, less than
about 20 wppm sulfur, less than about 15 wppm sulfur, less than
about 10 wppm sulfur, or less than about 5 wppm sulfur, based on
total weight of the hydroprocessed product.
[0053] If desired, water in the hydroprocessed product can be
removed prior to combining or blending with base fuel to produce
the low sulfur fuel. Removal of water can be accomplished using any
appropriate means, such as by flashing, decanting, distillation,
membrane separation, or the like, or a combination thereof. In one
embodiment, prior to combining or blending with base fuel, water
can be removed to produce a hydroprocessed product having a water
content of not greater than about 2 wt %, for example not greater
than about 1 wt % or not greater than about 0.5 wt %.
Reduced Sulfur Fuel
[0054] The hydroprocessed product produced according to the present
invention can be useful as a fuel or as a component of a fuel
product. The fuel that is produced can generally be a heavier fuel,
typically referred to as a bunker fuel, and can be particularly
advantageous in its reduction in sulfur content relative to current
bunker fuels.
[0055] Thus, in one embodiment, a fuel is provided that is a blend
product of hydroprocessed product and a base fuel. At least a
portion of the hydroprocessed product can be combined or blended
with the base fuel to produce a higher quality fuel and/or to meet
strict governmental and/or product fuel specifications. In
particular, the fuel that is produced can have a sulfur content of
not greater than about 5 wt %, for example not greater than about 4
wt %, not greater than about 3 wt %, not greater than about 2 wt %,
not greater than about 1 wt %, not greater than about 5000 wppm,
not greater than about 2000 wppm, not greater than about 1000 wppm,
not greater than about 500 wppm, not greater than about 200 wppm,
not greater than about 100 wppm, not greater than about 50 wppm,
not greater than about 30 wppm, not greater than about 20 wppm, not
greater than about 15 wppm, or not greater than about 10 wppm,
based on at least one of ISO 8754 or ISO 14596 test methods.
[0056] Base fuels that can be combined or blended with the
hydroprocessed product can generally comprise, consist essentially
of, or be any heavier refinery fraction. Such fractions are
typically heavier than gasoline or a majority of gasoline blend
stocks. Examples of base fuels include, but are not limited to, gas
oil, heavy fuel oil, atmospheric resid, vacuum resid, heavy cycle
oil, and the like, and mixtures thereof.
[0057] The base fuel combined or blended with the hydroprocessed
product can typically have an overall sulfur content in excess of
that of the hydroprocessed product, such that the blend can thereby
produce a reduced sulfur fuel. In one embodiment, the
hydroprocessed product can be combined or blended with a base fuel
having a sulfur content in excess of the hydroprocessed product to
produce a reduced sulfur fuel, e.g., the base fuel having a sulfur
content that is at least 10% in excess of that of the
hydroprocessed product, for example at least 50% in excess, at
least 100% in excess, at least 200% in excess, or at least 400% in
excess.
[0058] Additionally or alternately, the fuel produced according to
the present invention can be reduced in viscosity relative to
typical base (heavy) fuels. For example, the fuel that is produced
can have a kinematic viscosity at .about.50.degree. C. of not
greater than about 800, e.g., not greater than about 600, not
greater than about 400, or not greater than about 200, based on ISO
3104 test method.
[0059] Further additionally or alternately, the fuel produced
according to the present invention can be increased in flash point
relative to typical base (heavy) fuels. For example, the fuel that
is produced can have a flash point of at least about 40.degree. C.,
e.g., at least about 50.degree. C. or at least about 60.degree. C.,
based on ISO 2719 test method.
[0060] Still further additionally or alternately, the fuel produced
according to the present invention can be reduced in water content
relative to typical base (heavy) fuels. For example, the fuel that
is produced can have a water content of not greater than about 0.5
vol %, e.g., not greater than about 0.4 vol % or not greater than
about 0.3 vol %, based on ISO 3733 test method.
[0061] Specific examples of fuels produced according to the present
invention can include, but are not limited to, diesel fuels, home
heating oil, industrial heater and boiler fuel, and marine fuel,
preferably marine fuels of the distillate type (e.g., gas oil or
marine gas oil), intermediate type (e.g., marine diesel fuel or
intermediate fuel oil), and resid type (e.g., fuel oil or residual
fuel oil). Examples of marine distillate fuels can include, but are
not limited to, DM designated fuel grades (e.g., DMX, DMA, DMB, and
DMC). Examples of intermediate marine fuels can include, but are
not limited to, IF fuel grades (e.g., IFO 180 and 380). Examples of
resid fuel types can include, but are not limited to, RM designated
fuel grades (e.g., RMA to RML).
[0062] Additionally or alternately, the present invention can
include one or more of the following embodiments.
Embodiment 1.
[0063] A process for producing a reduced sulfur fuel, comprising:
hydroprocessing pyrolysis oil in the presence of a non-aluminum
support catalyst and hydrogen at a hydrogen to pyrolysis oil ratio
of not greater than about 1000 SCF/bbl (about 170 Nm.sup.3/m.sup.3)
to produce a hydroprocessed product; and combining at least a
portion of the hydroprocessed product with a base fuel in which the
base fuel has a sulfur content in excess of that of the
hydroprocessed product to produce the reduced sulfur fuel.
Embodiment 2.
[0064] A process for producing a reduced sulfur fuel, comprising:
pyrolyzing a hydrocarbon feedstock to produce a pyrolysis oil;
hydroprocessing the pyrolysis oil in the presence of a non-aluminum
support catalyst and hydrogen at a hydrogen to pyrolysis oil ratio
of not greater than about 1000 SCF/bbl (about 170 Nm.sup.3/m.sup.3)
to produce a hydroprocessed product; and combining at least a
portion of the hydroprocessed product with a base fuel in which the
base fuel has a sulfur content in excess of that of the
hydroprocessed product to produce the reduced sulfur fuel.
Embodiment 3.
[0065] The process of embodiment 1 or embodiment 2, wherein the
hydrocarbon feedstock comprises biomass.
Embodiment 4.
[0066] The process of any one of the previous embodiments, wherein
the non-aluminum-containing support catalyst comprises at least one
metal from Groups 8-10 of the Periodic Table of Elements.
Embodiment 5.
[0067] The process of any one of the previous embodiments, wherein
the non-aluminum-containing support comprises a carbon support or a
silica support.
Embodiment 6.
[0068] The process of embodiment 5, wherein the
non-aluminum-containing support catalyst comprises at least one of
palladium and platinum.
Embodiment 7.
[0069] The process of any one of the previous embodiments, wherein
the pyrolysis oil is comprised of one or more of aldehydes,
ketones, and carboxylic acids.
Embodiment 8.
[0070] The process of any one of the previous embodiments, wherein
the base fuel includes at least one gas oil, heavy fuel oil, or
resid oil component.
Embodiment 9.
[0071] The process of any one of the previous embodiments, wherein
the hydroprocessed product comprises at least 10 wt % non-aromatic
alcohols, based on total weight of the hydroprocessed product.
Embodiment 10.
[0072] The process of any one of the previous embodiments, wherein
the reduced sulfur fuel comprises a diesel fuel, a home heating
oil, an industrial heater or boiler fuel, a marine fuel, or a
combination thereof.
Embodiment 11.
[0073] The process of any one of the previous embodiments, wherein
the pyrolysis oil is a liquid fraction of a pyrolysis product.
[0074] The principles and modes of operation of this invention have
been described above with reference to various exemplary and
preferred embodiments. As understood by those of skill in the art,
the overall invention, as defined by the claims, encompasses other
preferred embodiments not specifically enumerated herein.
* * * * *