U.S. patent application number 12/912103 was filed with the patent office on 2011-05-05 for hydroprocessing feedstock containing lipid material to produce transportation fuel.
This patent application is currently assigned to EXXONMOBIL RESEARCH AND ENGINEERING COMPANY. Invention is credited to Edward S. Ellis, Patrick L. Hanks, Bal K. Kaul.
Application Number | 20110099891 12/912103 |
Document ID | / |
Family ID | 43923887 |
Filed Date | 2011-05-05 |
United States Patent
Application |
20110099891 |
Kind Code |
A1 |
Kaul; Bal K. ; et
al. |
May 5, 2011 |
HYDROPROCESSING FEEDSTOCK CONTAINING LIPID MATERIAL TO PRODUCE
TRANSPORTATION FUEL
Abstract
This invention provides processes for producing fuel,
particularly transportation fuel, from biological material, e.g.,
lipid material. One aspect of the invention involves
hydroprocessing a feedstock in a hydroprocessing zone that is
maintained at conditions that promote the efficiency of converting
the lipid-containing feedstock into transportation fuel. Such
conditions include one or more of maintaining CO content of the
hydroprocessing zone at a predetermined amount and recycling or
providing a hydrogen-containing gas to the hydroprocessing zone
that has been treated to remove CO.
Inventors: |
Kaul; Bal K.; (Fairfax,
VA) ; Hanks; Patrick L.; (Annandale, NJ) ;
Ellis; Edward S.; (Basking Ridge, NJ) |
Assignee: |
EXXONMOBIL RESEARCH AND ENGINEERING
COMPANY
Annandale
NJ
|
Family ID: |
43923887 |
Appl. No.: |
12/912103 |
Filed: |
October 26, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61280509 |
Nov 4, 2009 |
|
|
|
Current U.S.
Class: |
44/389 ;
44/388 |
Current CPC
Class: |
C10G 3/52 20130101; C10G
2300/4081 20130101; C10L 1/00 20130101; Y02P 30/20 20151101; C10G
2300/405 20130101; C10G 2300/1011 20130101; C10G 2300/42 20130101;
C10G 3/50 20130101; C10G 3/46 20130101 |
Class at
Publication: |
44/389 ;
44/388 |
International
Class: |
C10L 1/19 20060101
C10L001/19 |
Claims
1. A method for producing transportation fuel, comprising:
providing a feedstock containing lipid material and mineral oil,
wherein the lipid material is selected from the group consisting of
triglycerides, fatty acid alkyl esters and combinations thereof;
and hydroprocessing the feedstock in a hydroprocessing zone to
produce the transportation fuel, wherein the hydroprocessing zone
is maintained at not greater than 1000 vppm CO, based on total
vapor content of the hydroprocessing zone.
2. The method of claim 1, wherein a hydrogen-containing stream that
contains not greater than 200 vppm CO, based on total volume of the
hydrogen-containing stream, is added to the hydroprocessing zone
during hydroprocessing.
3. The method of claim 1, wherein the hydrogen-containing stream
that is added to the hydroprocessing zone during hydroprocessing
contains greater than 60 vol % H.sub.2, based on total volume of
the hydrogen-containing stream.
4. The method of claim 1, wherein the hydroprocessing zone contains
a CoMo or a NiMo hydroprocessing catalyst.
5. The method of claim 1, wherein the hydroprocessing produces a
hydroprocessed product comprised of a liquid fraction and a gas
fraction, and the gas fraction is separated from the liquid
fraction, with at least a portion of the liquid fraction forming
the transportation fuel.
6. The method of claim 5, wherein the separated gas fraction is
treated or contacted with a membrane or an adsorbent to remove at
least a majority of the CO from the gas stream to form a treated
gas stream, with the treated gas stream containing greater than 60
vol % H.sub.2 and not greater than 200 vppm CO, based on total
volume of the treated gas stream.
7. The method of claim 6, wherein the separated gas fraction is
treated or contacted with an adsorbent that is contained in a
pressure swing adsorption system or a rapid cycle pressure swing
adsorption system to form the treated gas stream.
8. The method of claim 6, wherein at least a portion of the treated
gas stream is added to the hydroprocessing zone during
hydroprocessing.
9. The method of claim 5, wherein at least a portion of the
separated gas fraction is acid gas treated.
10. The method of claim 1, wherein the feedstock includes at least
0.05 wt % lipid material, based on total weight of the
feedstock.
11. The method of claim 1, wherein the lipid material portion of
the feedstock is comprised of at least 20 wt % fatty acid alkyl
ester, based on total weight of the lipid material in the
feedstock.
12. A process for producing a transportation fuel, comprising:
providing a feedstock containing lipid material and mineral oil;
hydroprocessing the feedstock in a hydroprocessing zone to produce
a hydroprocessed product comprised of a liquid fraction and a gas
fraction; separating at least a portion of the gas fraction from
the hydroprocessed product; removing at least a majority of CO
contained in the separated gas fraction to form a treated gas
stream; providing at least a portion of the treated gas stream to
the hydroprocessing zone; and recovering at least a portion of the
liquid fraction as the transportation fuel.
13. The method of claim 12, wherein at least a portion of the gas
fraction separated from the hydroprocessed product is acid gas
treated prior to removing the CO.
14. The method of claim 12, wherein the hydroprocessing zone is
maintained at not greater than 1000 vppm CO, based on total vapor
content of the hydroprocessing zone.
15. The method of claim 12, wherein the separated gas fraction is
treated or contacted with a membrane or an adsorbent to remove the
CO and form the treated gas stream, with the treated gas stream
containing greater than 60 vol % H.sub.2 and not greater than 200
vppm CO, based on total volume of the treated gas stream.
16. The method of claim 15, wherein the separated gas fraction is
treated or contacted with an adsorbent that is contained in a
pressure swing adsorption system or a rapid cycle pressure swing
adsorption system to form the treated gas stream.
17. The method of claim 12, wherein the lipid material is selected
from the group consisting of triglycerides, fatty acid alkyl
esters, and combinations thereof.
18. The method of claim 12, wherein the hydroprocessing zone
contains a CoMo or a NiMo hydroprocessing catalyst.
19. The method of claim 12, wherein the feedstock includes at least
0.05 wt % lipid material, based on total weight of the
feedstock.
20. The method of claim 12, wherein the lipid material portion of
the feedstock is comprised of at least 20 wt % fatty acid alkyl
ester, based on total weight of the lipid material in the
feedstock.
Description
[0001] This Application claims the benefit of U.S. Application No.
61/280,509, filed Nov. 4, 2009.
FIELD OF THE INVENTION
[0002] This invention relates to the production of a fuel
composition from a feedstock that comprises lipid material and
mineral oil. More particularly, this invention relates to the
production of at least one transportation fuel composition from a
feedstock that comprises lipid material selected from the group
consisting of triglyceride, fatty acid alkyl ester and a
combination thereof, and mineral oil, wherein the transportation
fuel is produced by hydroprocessing the feedstock.
BACKGROUND OF THE INVENTION
[0003] An increased demand for fuel has generated interest in
finding feedstock other than crude oil or mineral oil. Various
biological oils have been under study for their potential use as
feedstock to product fuel, particularly transportation fuel. For
example, plant oils such as corn, rapeseed, canola and soybean oils
and greases, such as inedible tallow, yellow, and brown greases,
have been under study. A common feature of these types of oils is
that they are composed of triglycerides and free fatty acids that
generally have hydrocarbon chains from 8-20 carbons, which is also
a common characteristic of crude oil.
[0004] U.S. Pat. No. 7,511,181 discloses a process for producing a
hydrocarbon component useful as diesel fuel from biorenewable
feedstocks such as plant oils and greases. The process involves
hydrogenating and deoxygenating, i.e., decarboxylating and/or
hydrodeoxygenating, the feedstock to provide a hydrocarbon fraction
useful as a diesel fuel. An optional pretreatment step to remove
contaminants such as alkali metals from the feedstock can also be
carried out. The hydrocarbon fraction can be isomerized to improve
cold flow properties.
[0005] U.S. Pat. No. 7,232,935 discloses a process for producing a
hydrocarbon component of biological origin. The process comprises
at least two steps, the first of which is a hydrodeoxygenation
step, and the second of which is an isomerization step operated
using a counter-current flow principle. A biological raw material
containing fatty acids and/or fatty acid esters serves as the feed
stock.
[0006] In spite of the ongoing efforts to produce fuels using
biological materials as the feedstock, significant improvements
still need to be sought as there are many problems that must be
addressed. For example, transportation fuels such as diesel and
various jet fuels must meet tight specifications. Biological
materials alone cannot meet such specifications, without
hydroprocessing. However, hydroprocessing biological materials is
problematic to the extent that processing the biological materials
using current processes quite often result in excess heats of
reaction, a reduction in catalyst activity, and significant shifts
in co-product formation. Accordingly, there is a need for
additional improvement in producing fuels, particularly
transportation fuels, from feedstock containing biologically
derived material.
SUMMARY OF THE INVENTION
[0007] This invention provides processes for producing fuel,
particularly transportation fuel, from biological material, e.g.,
lipid material. The product can advantageously include one or more
high quality transportation fuels, such as gasoline, kerosene, jet
fuel, and diesel.
[0008] According to one aspect of the invention, there is provided
a method of producing transportation fuel, including providing a
feedstock containing lipid material and mineral oil. Preferably,
the lipid material can be selected from the group consisting of
triglycerides, fatty acid alkyl esters and combinations
thereof.
[0009] The feedstock can be hydroprocessed in a hydroprocessing
zone to produce the transportation fuel. Preferably, the
hydroprocessing zone can be maintained at not greater than 1000
vppm CO, based on total vapor content of the hydroprocessing
zone.
[0010] In one embodiment of the invention, a hydrogen-containing
stream that contains not greater than 200 vppm CO, based on total
volume of the hydrogen-containing stream, is added to the
hydroprocessing zone during hydroprocessing. Preferably, the
hydrogen-containing stream that is added to the hydroprocessing
zone during hydroprocessing contains greater than 60 vol % H.sub.2,
based on total volume of the hydrogen-containing stream.
[0011] In another embodiment, the hydroprocessing zone contains a
CoMo or a NiMo hydroprocessing catalyst.
[0012] In yet another embodiment, the hydroprocessing can produce a
hydroprocessed product comprised of a liquid fraction and a gas
fraction, and the gas fraction can advantageously be separated from
the liquid fraction, with at least a portion of the liquid fraction
forming the transportation fuel. Preferably, the separated gas
fraction can be treated or contacted with a membrane or an
adsorbent to remove at least a majority of the CO from the gas
stream to form a treated gas stream.
[0013] In one embodiment, the treated gas stream can contain
greater than 60 vol % H.sub.2 and not greater than 200 vppm CO,
based on total volume of the treated gas stream. In another
embodiment, the separated gas fraction can be treated or contacted
with an adsorbent contained in a pressure swing adsorption system
or a rapid cycle pressure swing adsorption system to form the
treated gas stream. Preferably, at least a portion of the treated
gas stream can be added to the hydroprocessing zone during
hydroprocessing. Additionally or alternately, at least a portion of
the separated gas fraction can be acid gas treated.
[0014] In general, the feedstock can include at least 0.05 wt %
lipid material, based on total weight of the feedstock.
Additionally or alternately, the lipid material portion of the
feedstock can be comprised of at least 20 wt % fatty acid alkyl
ester, based on total weight of the lipid material in the
feedstock.
[0015] According to another aspect of the invention, there is
provided a process for producing a transportation fuel that
includes hydroprocessing feedstock containing lipid material and
mineral oil in a hydroprocessing zone to produce a hydroprocessed
product comprised of a liquid fraction and a gas fraction. At least
a portion of the gas fraction can be separated from the
hydroprocessed product, and at least a portion of the liquid
fraction can be recovered as the transportation fuel.
[0016] In one embodiment, at least a majority of CO contained in
the separated gas fraction can be removed from the separated gas
fraction to form a treated gas stream, which can be provided or
recycled to the hydroprocessing zone. In another embodiment, at
least a portion of the gas fraction separated from the
hydroprocessed product can be acid gas treated prior to removing
the CO.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIGURE demonstrates two Cases (A and B) according to the
invention in which differing levels of hydrogen are added with a
combined mineral and biocomponent feed to hydrotreat the combined
feed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] This invention can increase, or maximize, the amount of
lipid or bio-material that can be converted to transportation fuel.
One aspect of this increase/maximization involves hydroprocessing a
feedstock that comprises the lipid material, while controlling the
process to limit undesirable side reactions that can cause
substantial increases in heats of reaction and that can produce
compounds that negatively impact catalyst efficiency.
Feedstock
[0019] The feedstock that is used in the invention is preferably a
combination feed containing both lipid material and mineral oil. By
"mineral oil" is meant a fossil/mineral fuel source, such as crude
oil, and not the commercial organic product, such as sold under the
CAS number 8020-83-5, e.g., by Aldrich. In one embodiment, the
lipid material and mineral oil are mixed together prior to
processing. In another embodiment, the lipid material and mineral
oil are provided as separate streams into appropriate processing
unit(s) or vessel(s).
[0020] The term "lipid material" as used according to the invention
is a composition comprised of biological materials. Generally,
these biological materials include vegetable fats/oils, animal
fats/oils, fish oils, pyrolysis oils, and algae lipids/oils, as
well as components of such materials. More specifically, the lipid
material includes one or more type of lipid compounds. Lipid
compounds are typically biological compounds that are insoluble in
water, but soluble in nonpolar (or fat) solvents. Non-limiting
examples of such solvents include alcohols, ethers, chloroform,
alkyl acetates, benzene, and combinations thereof.
[0021] Major classes of lipids include, but are not necessarily
limited to, fatty acids, glycerol-derived lipids (including fats,
oils and phospholipids), sphingosine-derived lipids (including
ceramides, cerebrosides, gangliosides, and sphingomyelins),
steroids and their derivatives, terpenes and their derivatives,
fat-soluble vitamins, certain aromatic compounds, and long-chain
alcohols and waxes.
[0022] In living organisms, lipids generally serve as the basis for
cell membranes and as a form of fuel storage. Lipids can also be
found conjugated with proteins or carbohydrates, such as in the
form of lipoproteins and lipopolysaccharides.
[0023] Examples of vegetable oils that can be used in accordance
with this invention include, but are not limited to rapeseed
(canola) oil, soybean oil, coconut oil, sunflower oil, palm oil,
palm kernel oil, peanut oil, linseed oil, tall oil, corn oil,
castor oil, jatropha oil, jojoba oil, olive oil, flaxseed oil,
camelina oil, safflower oil, babassu oil, tallow oil and rice bran
oil.
[0024] Vegetable oils as referred to herein can also include
processed vegetable oil material. Non-limiting examples of
processed vegetable oil material include fatty acids and fatty acid
alkyl esters. Alkyl esters typically include C.sub.1-C.sub.5 alkyl
esters. One or more of methyl, ethyl, and propyl esters are
preferred.
[0025] Examples of animal fats that can be used in accordance with
the invention include, but are not limited to, beef fat (tallow),
hog fat (lard), turkey fat, fish fat/oil, and chicken fat. The
animal fats can be obtained from any suitable source including
restaurants and meat production facilities.
[0026] Animal fats as referred to herein also include processed
animal fat material. Non-limiting examples of processed animal fat
material include fatty acids and fatty acid alkyl esters. Alkyl
esters typically include C.sub.1-C.sub.5 alkyl esters. One or more
of methyl, ethyl, and propyl esters are preferred.
[0027] Algae oils or lipids are typically contained in algae in the
form of membrane components, storage products, and metabolites.
Certain algal strains, particularly microalgae such as diatoms and
cyanobacteria, contain proportionally high levels of lipids. Algal
sources for the algae oils can contain varying amounts, e.g., from
2 wt % to 40 wt % of lipids, based on total weight of the biomass
itself.
[0028] Algal sources for algae oils include, but are not limited
to, unicellular and multicellular algae. Examples of such algae
include a rhodophyte, chlorophyte, heterokontophyte, tribophyte,
glaucophyte, chlorarachniophyte, euglenoid, haptophyte,
cryptomonad, dinoflagellum, phytoplankton, and the like, and
combinations thereof. In one embodiment, algae can be of the
classes Chlorophyceae and/or Haptophyta. Specific species can
include, but are not limited to, Neochloris oleoabundans,
Scenedesmus dimorphus, Euglena gracilis, Phaeodactylum tricornutum,
Pleurochrysis carterae, Prymnesium parvum, Tetraselmis chui, and
Chlamydomonas reinhardtii.
[0029] The lipid material portion of the feedstock is preferably
comprised of triglycerides, fatty acid alkyl esters, or preferably
combinations thereof. In one embodiment, the feedstock includes at
least 0.05 wt %, for example at least 0.1 wt %, at least 0.5 wt %,
or at least 1 wt % lipid material, based on total weight of the
feedstock provided for processing into fuel.
[0030] In a particular embodiment of the invention, the feedstock
includes not more than 40 wt %, preferably not more than 30 wt %,
for example not more than 20 wt %, not more than 10 wt %, or not
more than 5 wt % lipid material, based on total weight of the
feedstock.
[0031] In one embodiment, the lipid material contains one or more
triglycerides. Types of triglycerides can be determined according
to their fatty acid constituents. The fatty acid constituents can
be readily determined using Gas Chromatography (GC) analysis. This
analysis involves extracting the fat or oil, saponifying
(hydrolyzing) the fat or oil, preparing an alkyl (e.g., methyl)
ester of the saponified fat or oil, and determining the type of
(methyl) ester using GC analysis. In one embodiment, a majority
(i.e., greater than 50%) of the triglyceride present in the lipid
material can be comprised of C.sub.8 to C.sub.22 fatty acid
constituents, based on total triglyceride present in the lipid
material. For clarity, when a fatty acid or fatty acid ester
molecule is specified as a "C.sub.xx" fatty acid, fatty acid
constituent, or fatty acid ester, what is meant is that "xx" is the
number of carbons on the carbon side of the carboxylate linkage,
i.e., including the carboxylate carbon, whereas, in fatty acid
esters, the ester carbons are not included in the "C.sub.xx" and
are the carbons on the oxygen side of the carboxylate linkage,
i.e., stopping at the carboxylate oxygen. Further, a triglyceride
is a molecule having a structure identical to the reaction product
of glycerol and three fatty acids. Thus, although a triglyceride is
described herein as being comprised of fatty acids, it should be
understood that the fatty acid component does not necessarily
contain a carboxylic acid hydrogen. In the processes of the present
invention, a majority of the triglyceride present in the lipid
material can preferably be comprised of C.sub.10 to C.sub.18, for
example C.sub.12 to C.sub.18, fatty acid constituents, based on
total triglyceride present in the lipid material.
[0032] In a particular embodiment, the lipid material includes
triglyceride, with at least 20 wt %, preferably at least 30 wt %,
for example at least 40 wt %, of the triglyceride being comprised
of lauric acid (C 12:0) constituents. Using the notation "C xx:yy"
indicates a compound having "xx" carbons on the main chain, i.e.,
on the carbon side of the carboxylate group including the
carboxylate carbon, and having "yy" double bonds on that main
chain. Additionally or alternately, the lipid material includes
triglyceride, with 40 wt % to 60 wt %, for example from 42 wt % to
58 wt % or from 44 wt % to 55 wt %, of the triglyceride being
comprised of lauric acid constituents. Unless otherwise
unambiguously specified, percentages expressed herein are
percentages based on a number total of elements or
constituents.
[0033] Additionally or alternately, the lipid material includes
triglyceride, with at least 2 wt %, preferably at least 5 wt %, for
example at least 10 wt %, of the triglyceride being comprised of
myristic acid (C 14:0) constituents. Additionally or alternately,
the lipid material includes triglyceride, with 10 wt % to 28 wt %,
for example 12 wt % to 26 wt % or 14 wt % to 24 wt %, of the
triglyceride being comprised of myristic acid constituents.
[0034] Additionally or alternately, the lipid material includes
triglyceride, with at least 2 wt %, preferably at least 3 wt %, for
example at least 5 wt %, of the triglyceride being comprised of
palmitic acid (C 16:0) constituents. Additionally or alternately,
the lipid material includes triglyceride, with 2 wt % to 12 wt %,
for example 3 wt % to 10 wt % or 5 wt % to 8 wt %, of the
triglyceride being comprised of palmitic acid constituents.
[0035] Additionally or alternately, the lipid material includes
triglyceride, with at least 0.5 wt %, preferably at least 1 wt %,
for example at least 2 wt %, of the triglyceride being comprised of
stearic acid (C 18:0) constituents. Additionally or alternately,
the lipid material includes triglyceride, with 0.5 wt % to 60 wt %,
for example 1 wt % to 55 wt % or 2 wt % to 50 wt %, of the
triglyceride being comprised of stearic acid constituents.
[0036] Additionally or alternately, the lipid material includes
triglyceride, with at least 5 wt %, preferably at least 6 wt %, for
example at least 7 wt %, of the triglyceride being comprised of
oleic acid (C 18:1) constituents. Additionally or alternately, the
lipid material includes triglyceride, with 5 wt % to 30 wt %, for
example 6 wt % to 25 wt % or 7 wt % to 20 wt %, of the triglyceride
being comprised of oleic acid constituents.
[0037] Additionally or alternately, the lipid material includes
triglyceride, with at least 2 wt %, preferably at least 3 wt %, for
example at least 4 wt %, of the triglyceride being comprised of
erucic acid (C 22:1) constituents. Additionally or alternately, the
lipid material includes triglyceride, with 2 wt % to 70 wt %, for
example 3 wt % to 65 wt % or 4 wt % to 60 wt % of the triglyceride
being comprised of erucic acid constituents.
[0038] In one embodiment, the lipid material comprises fatty acid
alkyl ester. Preferably, the fatty acid alkyl ester comprises fatty
acid methyl esters (FAME), fatty acid ethyl esters (FAEE), and/or
fatty acid propyl esters.
[0039] In a particular embodiment of the invention, the lipid
material portion of the feedstock comprises fatty acid alkyl ester,
and a majority of the fatty acid alkyl ester present in the lipid
material is preferably FAME.
[0040] In another embodiment of the invention, the lipid material
portion of the feedstock can comprise at least 20 wt %, preferably
at least 30 wt %, for example at least 40 wt % fatty acid alkyl
ester, preferably FAME, based on total weight of the lipid
material. Preferably, a majority of the fatty acid constituents of
the fatty acid alkyl ester, preferably FAME, can be selected from
the group consisting of caprylic acid (C 8:0), capric acid (C
10:0), lauric acid (C 12:0), myristic acid (C 14:0), palmitic acid
(C 16:0), palmitoleic acid (C 16:1), stearic acid (C 18:0), oleic
acid (C 18:1), linoleic acid (C 18:2), linolenic acid (C 18:3),
erucic acid (C 22:1), and combinations thereof. In a particular
embodiment, a majority of the fatty acid constituents of the FAME
present in the lipid material portion can be selected from the
group consisting of lauric acid (C 12:0), myristic acid (C 14:0),
palmitic acid (C 16:0), palmitoleic acid (C 16:1), stearic acid (C
18:0), oleic acid (C 18:1), and combinations thereof, based on
total amount of FAME present in the lipid material portion.
[0041] The feedstock provided according to this invention comprises
a mineral oil. Examples of mineral oils can include, but are not
limited to, straight run (atmospheric) gas oils, vacuum gas oils,
demetallized oils, coker distillates, cat cracker distillates,
heavy naphthas (optionally but preferably at least partially
denitrogenated and/or at least partially desulfurized), diesel
boiling range distillate fraction (optionally but preferably at
least partially denitrogenated and/or at least partially
desulfurized), jet fuel boiling range distillate fraction
(optionally but preferably at least partially denitrogenated and/or
at least partially desulfurized), kerosene boiling range distillate
fraction (optionally but preferably at least partially
denitrogenated and/or at least partially desulfurized), and coal
liquids. The mineral oil that is included as a part of the
feedstock can comprise any one of these example streams or any
combination thereof that would be suitable for hydrocracking with
the lipid material portion. Preferably, the feedstock does not
contain any appreciable asphaltenes. In one embodiment, the mineral
oil can be mixed with the lipid material portion and then
hydrotreated to form a hydrotreated material. In another
embodiment, the mineral oil can be hydrotreated to reduce the
nitrogen and/or sulfur content before being mixed with the lipid
material portion.
[0042] The mineral oil component can contain nitrogen-containing
compounds (abbreviated as "nitrogen"). For example, the mineral oil
can contain at least 5 wppm nitrogen, based on total weight of the
mineral oil component. Preferably, the mineral oil will contain not
greater than 1.0 wt % nitrogen, based on total weight of the
mineral oil component. In general, at least a majority of the
nitrogen will be in the form of organonitrogen compounds.
[0043] The mineral oil will typically contain sulfur-containing
compounds (abbreviated as "sulfur" or "sulfur content"). Such
compounds can typically be present in the mineral oil at a sulfur
content greater than 500 wppm, or often greater than 0.1 wt %,
based on total weight of the mineral oil. Preferably, the sulfur
content of the mineral oil will not be greater than 6 wt %,
preferably not greater than 4 wt %, based on total weight of the
mineral oil.
[0044] In one embodiment, the feedstock can include not greater
than 99.5 wt %, for example not greater than 99 wt %, not greater
than 98 wt %, not greater than 95 wt %, not greater than 90 wt %,
or not greater than 85 wt % mineral oil, based on total weight of
the feedstock.
[0045] Additionally or alternately, the feedstock can include at
least 50 wt % mineral oil, based on total weight of the feedstock.
Preferably, the feedstock can include at least 60 wt %, for example
at least 70 wt %, at least 75 wt %, at least 80 wt %, or at least
85 wt % mineral oil, based on total weight of the feedstock.
[0046] According to one aspect of the invention, the feedstock that
is hydrocracked can have an initial boiling point of at least
100.degree. C., preferably at least 150.degree. C., for example at
least 180.degree. C. or at least 200.degree. C. The basic test
method of determining the boiling points or ranges of such
feedstock, as well as the fuel compositions produced according to
this invention, can be by performing batch distillation according
to ASTM D86-09e1, Standard Test Method for Distillation of
Petroleum Products at Atmospheric Pressure.
[0047] Additionally or alternately, the feedstock can have a final
boiling point of not greater than 500.degree. C., preferably not
greater than 450.degree. C., for example not greater than
400.degree. C.
[0048] The feedstock can preferably be converted to a product by
hydroprocessing, preferably in a continuous operation process. In
one embodiment, hydroprocessing can be carried out at a liquid
hourly space velocity (LHSV) from 0.1 hr.sup.-1 to 20 hr.sup.-1,
for example from 0.1 hr.sup.-1 to 5 hr.sup.-1.
Hydroprocessing
[0049] The transportation fuel produced according to this invention
can advantageously include hydroprocessing of the desired feedstock
in a hydroprocessing zone. Hydroprocessing is a process in which
feed material is treated or contacted with hydrogen, optionally but
preferably in the presence of a hydroprocessing catalyst. The
hydrogen (and/or catalyst) in the process serves to reduce or
remove hetero- (non-carbon) atoms from the feed such as nitrogen,
sulfur, and oxygen. The hydrogen (and/or catalyst) in the process
can also be used to saturate carbon compounds and/or to increase
the ratio of isoparaffins to normal paraffins in the product
composition. Examples of hydroprocessing processes for lipid (bio-)
material include, but are not limited to, hydrodeoxygenation,
hydrotreating, hydrocracking, hydrogenation (including
dearomatization), dewaxing, hydroisomerization, and hydrofinishing.
Additional (or alternate) hydroprocessing processes for mineral
feeds can include hydrodenitrogenation, hydrodesulfurization, and
the like.
CO Control
[0050] The hydroprocessing zone can be maintained during the
process at conditions that promote the efficiency of converting the
lipid-containing feedstock into transportation fuel. In one
embodiment, the hydroprocessing zone can be maintained at not
greater than 1000 vppm CO (carbon monoxide), for example not
greater than 900 vppm CO, not greater than 800 vppm CO, or not
greater than 700 vppm CO, based on total vapor content of the
hydroprocessing zone.
[0051] It may also be preferred that, during hydroprocessing, a
hydrogen-containing stream be added to the hydroprocessing zone.
Preferably, the hydrogen-containing stream contains greater than 60
vol % H.sub.2, more preferably at least 70 vol % H.sub.2, for
example at least 80 vol % H.sub.2 or at least 90 vol % H.sub.2,
based on total volume of the hydrogen-containing stream.
[0052] The hydrogen-containing stream can also be referred to by
other names such as a treat gas stream, a hydrogen stream, or a
hydrogen treat gas stream. It is not necessary that the stream be
pure H.sub.2, as long as the stream does not contain levels of
impurities that would substantially negatively impact
hydroprocessing of the feedstock to efficiently form transportation
fuel.
[0053] In one embodiment of the invention, the hydrogen-containing
stream added to the hydroprocessing zone contains not greater than
200 vppm CO, preferably not greater than 100 vppm CO, for example
not greater than 50 vppm CO, not greater than 10 vppm CO, or not
greater than 5 vppm CO, based on total volume of the
hydrogen-containing stream added to the hydroprocessing zone during
hydroprocessing.
[0054] The amount of hydrogen added to the hydroprocessing zone
should be sufficient to reduce one or more of nitrogen, sulfur, and
oxygen atoms in the liquid product portion or fraction by at least
a desired amount. In one embodiment, the hydrogen-containing stream
added to the hydroprocessing zone can be added at volume ratio of
hydrogen-containing stream to feedstock (i.e., treat gas rate) from
300 scf/bbl (53 Nm.sup.3/m.sup.3) to 5000 scf/bbl (890
Nm.sup.3/m.sup.3). Preferably, the hydrogen-containing treat gas
rate can be from 2000 scf/bbl (360 Nm.sup.3/m.sup.3) to 4000
scf/bbl (710 Nm.sup.3/m.sup.3).
Hydrodeoxygenation
[0055] According to an aspect of the invention, at least a portion
of the feedstock can be hydrodeoxygenated during hydroprocessing or
as a part of the hydroprocessing process. Hydrodeoxygenation refers
to oxygen reduction and/or removal from a compound by means of
hydrogen. Water is typically liberated in the reaction, olefinic
(double) bonds may be hydrogenated (saturated), and various sulfur
and nitrogen compounds may be removed, if present.
Hydrodeoxygenation reactions are typically exothermic.
[0056] In one embodiment, hydrodeoxygenation can be carried out in
a hydroprocessing zone at a pressure from 0.1 MPa to 20 MPa, for
example from 1 MPa to 15 MPa. Additionally or alternately,
hydrodeoxygenation can be carried out in a hydroprocessing zone at
a temperature from 100.degree. C. to 500.degree. C., for example
from 150.degree. C. to 350.degree. C.
[0057] In a preferred embodiment, hydrodeoxygenation can be carried
out by treating the feedstock in the presence of a catalyst
containing at least one Group VIII metal, at least one Group VIB
metal, or a combination thereof. In one embodiment, the catalyst
can preferably comprise Pd, Pt, Ru, Rh, Ni, NiMo, or CoMo metals,
for example in the form of a supported catalyst, with a preferred
support comprising activated carbon, alumina, silica or a
combination thereof.
[0058] Preferably, feedstock can be brought into contact or can be
treated with the catalyst in the presence of hydrogen at operating
temperatures and pressures sufficient to hydrodeoxygenate at least
a majority (i.e., more than 50 wt %) of any alcohols and to
saturate at least a majority of any olefins present in the feed.
The reaction temperature used in the hydroprocessing zone can be in
the range from 100.degree. C. to 350.degree. C., preferably from
150.degree. C. to 300.degree. C. or from 150.degree. C. to
275.degree. C. Additionally or alternately, the reaction pressure
within the hydroprocessing zone can be in the range from 5 bara to
150 bara (0.5 MPag to 15 MPag), preferably from 10 bara to 100 bara
(1.0 MPag to 10 MPag), for example from 10 bara to 90 bara (1.0
MPag to 9.0 MPag).
Hydrotreating
[0059] According to an aspect of the invention, at least a portion
of the feedstock can be hydrotreated during hydroprocessing or as a
part of the hydroprocessing process. Hydrotreating typically
results in the reduction and/or removal of hetero- (non-carbon)
atoms, such as nitrogen and/or sulfur, from the feedstock.
[0060] In one embodiment, hydrotreating can be carried out at a
temperature from 400.degree. F. to 900.degree. F. (204.degree. C.
to 482.degree. C.), for example from 650.degree. F. to 850.degree.
F. (343.degree. C. to 454.degree. C.). Additionally or alternately,
hydrotreating can be carried out at a pressure from 500 psig to
5000 psig (3.5 MPag to 34.6 MPag), for example from 1000 psig to
3000 psig (7.0 MPag to 20.8 MPag).
[0061] A preferred hydrotreating catalyst can comprise at least one
Group VIB metal and at least one Group VIII metal, either as a bulk
catalyst or optionally supported on a porous refractory base
material. The Groups referred to herein are Groups found in the
Periodic Table of the Elements in Hawley's Condensed Chemical
Dictionary, 13.sup.th Edition. Examples of such base materials
include, but are not limited to, alumina, silica, alumina-silica,
zirconia, and combinations thereof. Preferred catalyst metals
useful in the process of this invention can include, but are not
limited to, cobalt-molybdenum, nickel, nickel-tungsten,
cobalt-tungsten, nickel-molybdenum, nickel-cobalt-molybdenum,
nickel-cobalt-tungsten, nickel-molybdenum-tungsten, and
cobalt-molybdenum-tungsten, optionally but preferably supported
with activated carbon, alumina, silica, or a combination
thereof.
Hydrocracking
[0062] According to an aspect of the invention, at least a portion
of the feedstock can be hydrocracked during hydroprocessing or as a
part of the hydroprocessing process. Hydrocracking is a particular
hydroprocessing process that includes cracking or breaking larger
carbon number molecules into smaller carbon number molecules.
[0063] In one embodiment, hydrocracking of the feedstock can be
carried out in the hydroprocessing zone at a temperature in the
range from 600.degree. F. to 900.degree. F. (316.degree. C. to
482.degree. C.), for example from 650.degree. F. to 850.degree. F.
(343.degree. C. to 454.degree. C.). Additionally or alternately,
hydrocracking of the feedstock can be carried out in the
hydroprocessing zone at a pressure in the range from 200 psia to
4000 psia (13 atm to 270 atm, or 1.4 MPaa to 27.6 MPaa), for
example from 500 psia to 3000 psia (34 atm to 200 atm, or 3.4 MPaa
to 20.7 MPaa).
[0064] Hydroprocessing can typically be carried out in a
hydroprocessing zone that includes a catalyst capable of carrying
out a cracking reaction, which catalyst, in one embodiment, is
comprised of an amorphous or zeolitic base and one or more Group
VIII and/or Group VIB metal hydrogenation components. In another
embodiment, the hydrocracking catalyst can comprise a crystalline
zeolite cracking base upon which is deposited at least one Group
VIII or Group VIB metal hydrogenating component. The Groups
referred to herein are Groups found in the Periodic Table of the
Elements in Hawley's Condensed Chemical Dictionary, 13.sup.th
Edition. Examples of Group VIII metals can include Fe, Co, and Ni,
preferably Co and/or Ni; examples of Group VIB metals include Mo
and/or W.
[0065] The zeolite cracking bases, which can be used as a component
of the hydrocracking catalyst, are also generally referred to as
molecular sieves. These materials can be composed of silica,
alumina, and one or more exchangeable cations, such as sodium,
magnesium, calcium, and one or more rare earth metals.
[0066] In one embodiment, a large pore crystalline molecular sieve
can be used. Preferably, the crystalline molecular sieve has a
Constraint Index of less than 2, more preferably less than 1. The
method by which the Constraint Index is determined is fully
described in U.S. Pat. No. 4,016,218, which is incorporated herein
by reference.
[0067] In another embodiment, the hydrocracking catalyst can be
comprised of a molecular sieve having a pore size of at least 7
angstroms, preferably at least 7.4 angstroms, for example at least
8 angstroms. Additionally or alternately, the hydrocracking
catalyst can be comprised of a molecular sieve having a pore size
of not greater than 15 angstroms, for example not greater than 12
angstroms.
[0068] Examples of zeolite molecular sieves that can be used in the
hydrocracking catalyst can include, but are not limited to, Zeolite
Beta, Zeolite X, Zeolite Y, faujasite, Ultrastable Y (USY),
Dealuminized Y (Deal Y), Mordenite, ZSM-3, ZSM-4, ZSM-18, ZSM-20,
and the like, and combinations thereof.
[0069] Typically, the hydrocracking catalyst has at least some
acidity. Preferably, the hydrocracking catalyst has an alpha value
greater than 1, for example greater than 5 or greater than 10. The
alpha value is a measure of zeolite acidic functionality and is
described in greater detail in U.S. Pat. No. 4,016,218 and in J.
Catalysis, Vol. VI, pages 278-287 (1966).
[0070] It is not necessary that the hydrocracking catalyst be
highly acidic, although a highly acidic catalyst can be used. In
one embodiment, the hydrocracking catalyst has an alpha value of
not greater than 200, for example not greater than 100.
[0071] Hydrocracking can be carried out under conditions effective
for producing the desired fuel product. Preferably, hydrocracking
can be carried out at an average reaction temperature from
300.degree. F. to 900.degree. F. (149.degree. C. to 482.degree.
C.), for example from 550.degree. F. to 800.degree. F. (289.degree.
C. to 427.degree. C.).
[0072] Hydrocracking can also be preferably carried out at an
average reaction pressure from 400 psia to 3000 psia (27 atm to 200
atm, or 2.8 MPaa to 20.7 MPaa), preferably from 500 psia to 2000
psia (34 atm to 136 atm, or 3.5 MPaa to 13.8 MPaa).
Hydrogenation
[0073] According to an aspect of the invention, at least a portion
of the feedstock can be hydrogenated during hydroprocessing or as a
part of the hydroprocessing process. Hydrogenation generally
involves saturating unsaturated carbon bonds, including saturating
aromatic rings. Preferably, hydrogenation can be carried out in the
hydroprocessing zone at a temperature in the range from 300.degree.
F. to 800.degree. F. (149.degree. C. to 427.degree. C.), for
example from 400.degree. F. to 600.degree. F. (204.degree. C. to
316.degree. C.).
[0074] In one embodiment, hydrogenation can be carried out in the
hydroprocessing zone at a pressure from 50 psig to 2000 psig (0.34
MPag to 13.8 MPag), for example from 100 psig to 500 psig (0.69
MPag to 3.4 MPag).
[0075] In one embodiment, hydroprocessing can be carried out in a
hydroprocessing zone that includes a catalyst capable of carrying
out a hydrogenation reaction. Catalysts that are useful in carrying
out hydrotreating reactions are generally also useful in
hydrogenation reactions. Exemplary catalysts can include
non-sulfided catalysts containing one or more of Pt and Pd,
preferably dispersed on a support, such as alumina, silica,
silica-alumina, carbon, or the like, or a combination thereof A
particularly preferred support is silica-alumina.
Dewaxing
[0076] According to an aspect of the invention, at least a portion
of the feedstock can be dewaxed during hydroprocessing or as a part
of the hydroprocessing process. Dewaxing in this invention refers
to catalytic dewaxing in which a heavier hydrocarbon reacts with
hydrogen in the presence of a dewaxing catalyst at dewaxing
reaction conditions. The catalytic dewaxing process is, in essence,
a type of hydrocracking process. Dewaxing is more particularly
based on selective hydrocracking of predominantly normal
paraffins.
[0077] Dewaxing typically incorporates the use of a molecular
sieve-based catalyst in which active hydrocracking sites are
accessible to contact with the paraffin molecules and preferably
not accessible to aromatic type compounds. The reactions conditions
in dewaxing are preferably effective to improve at least one of
freeze point, cloud point, pour point, and cold filter plug point
of the desired transportation fuel produced according to the
invention.
[0078] Any catalyst effective in dewaxing hydrocarbon can be used.
In one embodiment, a hydrotreating catalyst can be used as a
dewaxing catalyst, particularly those that include one or more of
Co, Ni, and Fe, in combination with one or more of Mo or W. In
another embodiment, a hydrodeoxygenation catalyst or a
hydrogenation catalyst can be used as a dewaxing catalyst, such as
Pt and/or Pd noble metals on an acidic support. Additionally or
alternately, the dewaxing catalyst can include an acidic oxide
support or carrier. Non-limiting examples of such carrier can
include, but are not limited to, silica, alumina, silica-alumina,
shape selective molecular sieves, and the like, and combinations
thereof. Preferably, the carrier can be combined with at least one
catalytic component such as titania, zirconia, vanadia, other Group
IIA, IVB, VB, or VIB oxides, ferrierite, mordenite, ZSM-5, ZSM-11,
ZSM-23, ZSM-35, ZSM-22 (also known as theta one or TON), ZSM-48,
silicoaluminophosphates (SAPOs) including SAPO-11, -36, -37 and
-40, zeolite Y sieves such as ultrastable Y, and the like, as well
as combinations thereof. If stripping is not available prior to
dewaxing and/or if the sulfur content of the hydrotreated and
separated heavy fraction is high enough to result in dewaxing
catalyst activity reduction or loss, zeolites containing framework
transition metals having improved sulfur resistance (see, e.g.,
U.S. Pat. Nos. 5,185,136, 5,185,137, and 5,185,138) may be
employed.
[0079] The dewaxing can be carried out at reaction conditions which
include an average hydroprocessing zone temperature from
300.degree. F. to 900.degree. F. (149.degree. C. to 482.degree.
C.), for example from 550.degree. F. to 800.degree. F. (289.degree.
C. to 427.degree. C.). Dewaxing can also be carried out at an
average reaction pressure from 400 psia to 2000 psia (27 atm to 136
atm, or 2.8 MPaa to 13.8 MPaa).
Hydroisomerization
[0080] According to an aspect of invention, at least a portion of
the feedstock can be hydroisomerized during hydroprocessing or as a
part of the hydroprocessing process. The terms "hydroisomerize,"
"hydroisomerized," and "hydroisomerization," as used herein, all
refer to a catalytic process in which feedstock is contacted with
catalyst in the presence of hydrogen and in which a substantial
portion of waxy paraffin compounds in the feedstock is converted to
non-waxy (e.g., branched and/or iso-) paraffins, while at the same
time minimizing conversion of normal paraffins (n-paraffins) by
cracking. Hydroisomerization can effectively increase the volume of
transportation fuel formed in the overall process. In particular, a
hydroprocessing process in which at least a portion of the
feedstock is hydroisomerized can reduce the heavier portion of the
feedstock by transforming that component into an additional volume
of transportation fuel.
[0081] Hydroisomerization can be carried out using a shape
selective molecular sieve catalyst. Large pore crystalline
molecular sieves or intermediate pore molecular sieves are
particularly effective.
[0082] Large pore crystalline molecular sieves useful in the
hydroisomerization aspect this invention preferably have a
Constraint Index of less than 2. Intermediate pore crystalline
molecular sieves useful in the hydroisomerization step of this
invention preferably have a Constraint Index of at least 2. The
method by which the Constraint Index is determined is fully
described in U.S. Pat. No. 4,016,218, which is incorporated herein
by reference.
[0083] In one embodiment, the molecular sieves used in the
hydroisomerization aspect of this invention have an alpha value of
less than 100. The alpha value is an approximate indication of the
catalytic cracking activity of the catalyst compared to a standard
catalyst. The alpha test gives the relative rate constant (rate of
normal hexane conversion per volume of catalyst per unit time) of
the test catalyst relative to the standard catalyst which is taken
as an alpha of 1 (Rate Constant=0.016 sec.sup.-1). The alpha test
is described in U.S. Pat. No. 3,354,078 and in J. Catalysis, 4, 527
(1965); 6, 278 (1966); and 61, 395 (1980), to which reference is
made for a description of the test. The experimental conditions of
the test used to determine the alpha values referred to in this
specification include a constant temperature of 538.degree. C. and
a variable flow rate as described in detail in J. Catalysis, 61,
395 (1980).
[0084] Non-limiting examples of large pore molecular sieve
catalysts can include, but are not limited to, molecular sieves
selected from the group consisting of zeolite beta, mordenite,
zeolite Y, ZSM-20, ZSM-4 (omega), zeolite L, VPI-5, SAPO-37,
MeAPO-37, AlPO-8, cloverite, and combinations thereof. Non-limiting
examples of intermediate pore molecular sieves can include, but are
not limited to, ZSM-22, ZSM-23, ZSM-48, SAPO-11, SAPO-5, MeAPO-11,
MeAPO-5, and combinations thereof; and an example of a
non-intersecting two-dimensional intermediate pore molecular sieve
is ZSM-35 (synthetic ferrierite).
[0085] Catalysts useful in the hydroisomerization step preferably
contain a hydrogenation metal, which can be one or more noble
metals, one or more non-noble metals, or a combination thereof.
Suitable noble metals include Group VIII noble metals, such as
platinum and other members of the platinum group, such as iridium,
palladium, and rhodium, and combinations of these metals. Suitable
non-noble metals include those of Groups VB, VIB, and (the
non-noble metals of) VIII of the Periodic Table. Preferred
non-noble metals include, but are not limited to, chromium,
molybdenum, tungsten, cobalt, nickel, and combinations of these
metals, including cobalt-molybdenum, nickel-tungsten,
nickel-molybdenum, cobalt-nickel-molybdenum,
nickel-molybdenum-tungsten, cobalt-molybdenum-tungsten, and
cobalt-nickel-tungsten. The non-noble metals can be pre-sulfided
prior to use by exposure to a sulfur-containing gas such as
hydrogen sulfide at an elevated temperature to effect conversion
(e.g., of the oxide form) to the corresponding sulfide form of the
metal.
[0086] The metal can be incorporated into the catalyst by any
suitable method or combination of methods, such as by impregnation
or ion exchange into the zeolite. The metal can be incorporated in
the form of a cationic, anionic, or neutral complex. Cationic
complexes of the type Pt(NH.sub.3).sub.4.sup.++ can be used for
exchanging metals onto the zeolite. Anionic complexes such as the
molybdate or metatungstate ions can also be useful for impregnating
metals into the catalysts.
[0087] In one embodiment, the hydroisomerization catalyst can
comprise a zeolite and a hydrogenation metal. In one preferred
embodiment, the catalyst can comprise from 0.01 wt % to 20 wt %,
for example from 0.1 wt % to 15 wt %, of hydrogenation metal, based
on total weight of the catalyst.
[0088] The molecular sieve, in one embodiment, can include a binder
(or matrix) material. Binder materials are preferably metal oxides.
Non-limiting examples of metal oxide binders can include, but are
not limited to, alumina, silica-alumina, silica-magnesia,
silica-zirconia, silica-thoria, silica-beryllia, silica-titania, as
well as ternary compositions such as silica-alumina-thoria,
silica-alumina-zirconia, silica-alumina-magnesia, and
silica-magnesia-zirconia, and the like, and combinations thereof.
In one embodiment, the catalysts are ZSM-23, ZSM-48 or SAPO-11, and
zeolite beta, which are combined with alumina, and formed into a
useable shape by methods such as extrusion or tabletting.
[0089] Hydroisomerization can be carried out in the presence of
hydrogen gas under hydroprocessing conditions of elevated
temperature and pressure. Particular reaction conditions for
hydroisomerization can depend on the feed used, the catalyst used,
whether or not the catalyst is sulfided, the desired yield, and the
desired properties of the desired product, inter alia. Conditions
under which the hydroisomerization process of this invention can be
carried out include temperatures from 600.degree. F. to 750.degree.
F. (315.degree. C. to 399.degree. C.), for example from 600.degree.
F. to 700.degree. F. (315.degree. C. to 371.degree. C.), and
pressures from 1.7 atm to 204 atm (25 psia to 3000 psia, or 170
kPaa to 20.7 MPaa), for example 6.8 atm to 170 atm (100 psia to
2500 psia, or 1.4 MPaa to 17.3 MPaa). Hydroisomerization pressures
in this context refer to the hydrogen partial pressure within the
hydroisomerization reactor, although the hydrogen partial pressure
is the same as or substantially the same as the total pressure when
the treat gas is 100% or substantially 100% hydrogen. However, the
total pressure will be greater than the hydrogen partial pressure
when the treat gas contains hydrogen and other usually relatively
inert gases.
Hydrofinishing
[0090] According to an aspect of invention, at least a portion of
the feedstock can be hydrofinished during hydroprocessing or as a
part of the hydroprocessing process. Hydrofinishing refers to
treating the feedstock with hydrogen to saturate at least a portion
of the feedstock for improved (oxidative) stability.
[0091] Hydroprocessing catalysts that can accomplish a
hydrofinishing aspect can include catalysts containing at least one
Group VIB metal and at least one Group VIII metal. Such a catalyst
can include at least one noble metal having a strong hydrogenation
function, such as platinum and/or palladium. A mixture of metals
can be present as bulk metal catalysts, wherein the amount of metal
is 50 wt % or greater, for example 60 wt % or greater or 70 wt % or
greater, based on the catalyst. Suitable metal oxide supports, when
present, can include relatively low acidic oxides, such as silica,
alumina, silica-alumina, titania, and combinations thereof,
preferably at least including alumina Non-noble metal content of
the catalyst can be up to 20 wt %, but is preferably not greater
than about 1 wt %.
[0092] In one embodiment, the catalyst can be a mesoporous material
belonging to the M41S class or family of catalysts. Examples can
include, but are not limited to, MCM-41, MCM-48, MCM-50, and the
like, and combinations thereof. The term "mesoporous" refers to
catalysts having pore sizes ranging from 15 to 100 angstroms. The
mesoporous materials can include a metal hydrogenation component,
which can be at least one Group VIII metal. Preferred are noble
Group VIII metals, particularly Pt and/or Pd.
[0093] In one embodiment, the hydrofinishing aspect can be carried
out at a temperature in a range from 150.degree. C. to 350.degree.
C., for example 180.degree. C. to 250.degree. C. Total pressure in
the hydroprocessing zone can be in a range from 400 psig to 3000
psig (2.8 MPag to 20.7 MPag).
Separation of Liquid and Gas Streams Formed in Hydroprocessing
[0094] Hydroprocessing the feedstock in this invention can
advantageously produce a hydroprocessed product comprised of a
liquid fraction and a gas fraction. The gas fraction can be
separated from the liquid fraction, with at least a portion of the
liquid fraction preferably forming a transportation fuel.
Separation can be accomplished by any suitable means. Such means
can include, but are not limited to, flash separation,
distillation, and the like.
Treatment of Gas Stream to Form Hydrogen Stream
[0095] In one embodiment, the separated gas fraction can be further
processed to remove CO or to reduce the CO content in order to form
a treated gas fraction. Preferably, the hydrogen-containing stream
added to the hydroprocessing zone can comprise at least a portion
of this treated gas fraction.
[0096] In a particular embodiment, a gas fraction can be separated
from the hydroprocessed product and can then be treated or
contacted with a membrane or an adsorbent to remove at least a
majority (i.e., at least 50%) of the CO from the gas stream to form
a treated gas stream. Treatment/contact/adsorption can be carried
out to recover a treated gas stream comprised of not greater than
50 vppm CO, preferably not greater then 20 vppm CO, for example not
greater than 10 vppm CO or not greater than 5 vppm CO, based on
total volume of the treated gas stream.
[0097] In one embodiment, at least a portion of the gas fraction of
the hydroprocessed product can be contacted with a membrane to
remove at least a portion of the CO from the gas stream form a
treated gas stream. The membrane can preferably be a membrane
preferential for permeation of hydrogen gas over carbon monoxide
(and optionally carbon dioxide). Examples of such membranes can
include, but are not limited to, membranes comprised of silicon
rubber, butyl rubber, polycarbonate, poly(phenylene oxide), nylon
6,6, polystyrene, polysulfones, polyamides, polyimides, polyethers,
polyarylene oxides, polyurethanes, polyesters, and combinations and
copolymers thereof. In one preferred embodiment, the hydrogen gas
permeation membrane can be of hollow fiber construction.
[0098] In a particular embodiment, at least a portion of the gas
fraction of the hydroprocessed product can be contacted with the
preferential hydrogen gas permeation membrane at a pressure at
which the non-permeate pressure can remain sufficiently high to
allow downstream use without further compression. Preferably, at
least a portion of the gas fraction of the hydroprocessed product
can be passed along or across the preferential hydrogen gas
permeation membrane at a pressure in the range from 500 psig to
2000 psig (34 atm to 140 atm, or 3.4 MPag to 13.8 MPag), for
example from 800 psig to 1200 psig (54 atm to 82 atm, or 5.5 MPag
to 8.3 MPag). A hydrogen-rich gas can permeate through the
membrane, and the permeate can generally experience a pressure drop
in the range from about 300 psig to 700 psig (3.1 MPag to 4.7 MPag)
as it passes through the membrane. After membrane separation, the
permeate can generally be at a pressure in the range from 200 psig
to 1500 psig (1.4 MPag to 10.3 MPag).
[0099] In another embodiment of the invention, an adsorbent
material can be used to remove at least a majority of the CO from
the gas stream to form the treated gas stream. In this embodiment,
the adsorbent material can be an adsorbent having a greater
affinity for carbon monoxide (and optionally but preferably also a
greater affinity for carbon dioxide and/or for methane) than for
hydrogen. The adsorbent material may be a molecular sieve,
activated carbon, or a combination thereof. Additionally or
alternately, one or more of calcium and sodium aluminosilicate
zeolites can be employed. Carbon molecular sieves and silica
molecular sieves can additionally or alternately be used. Suitable
zeolite sieves can include, but are not limited to, types 5A, 10X,
and 13X zeolite molecular sieves, mordenites, and the like.
Preferred zeolite sieves can include type 5A zeolite sieves and
molecular sieves with comparable pore size and molecular attraction
affinity.
[0100] In another embodiment, the adsorbent material can be an
adsorbent having a greater affinity for carbon monoxide than for
hydrogen, carbon dioxide, and methane. Non-limiting examples of
such materials can include copper-exchanged substrates, such as
copper-exchanged Y-type aluminosilicate zeolite molecular sieves,
copper-exchanged alumina, copper-exchanged activated carbon, and
combinations thereof. In one particular embodiment, the adsorbent
material can be or include copper aluminosilicate zeolite molecular
sieve material, such as commercially available under the tradename
NKK type adsorbent from Nippon Kokan K.K. of Tokyo, Japan.
[0101] According to an aspect of the invention, adsorption of the
CO from the gas stream can be carried out in pressure swing
adsorption system. In a pressure swing adsorption system, a gas
stream can be passed through a bed of an adsorbent material which
selectively adsorbs one or more of the components of the gas
stream. Treated gas, enriched in the unadsorbed gaseous
component(s), can then be withdrawn from the bed and either further
treated or in some other way recycled or utilized.
[0102] A pressure swing adsorption system typically employs at
least two adsorbent beds operated on cycles that are sequenced to
be out of phase with one another, so that, when at least one bed is
in the adsorption or production step, at least one other bed can be
in a regeneration step. Multiple adsorption beds may be connected
in series or in parallel. Generally, series arrangements of beds
are preferred for obtaining a high purity gas product, with
parallel arrangements of beds typically being preferred for
purifying a large quantity of a gaseous mixture in a short time
cycle.
[0103] In a preferred embodiment, adsorption of the CO from the gas
stream is carried out in a rapid cycle pressure swing adsorption
system. Rapid cycle pressure swing adsorption (RCPSA) is primarily
characterized relative to standard or conventional pressure swing
adsorption (PSA) by relatively shorter, or more rapid, cycles. For
example, RCPSA cycle times are typically less than a minute,
preferably not greater than 30 seconds, for example not greater
than 15 seconds, not greater than 10 seconds, or not greater than 5
seconds, while PSA cycle times are typically 2-4 minutes or
greater. Hardware (e.g., valves, piping, configuration of vessels)
to perform these cycles also tends to differ considerably, and
commercial vendors of equipment for both PSA and RCPSA exist.
[0104] An example of an RCPSA apparatus that can be used according
to this invention is described in U.S. Patent Publication
Application No. 2009/0071332. In an embodiment, the CO can be
removed using an RCPSA having a rotary valving system to conduct
the gas flow through a rotary sorber module that contains a number
of separate adsorbent bed compartments or "tubes," each of which
can be successively cycled through the sorption and desorption
steps as the rotary module completes the cycle of operations. In
this embodiment, the rotary sorber module can preferably be
comprised of multiple tubes held between two seal plates on either
end of the rotary sorber module, which seal plates can be in
contact with a stator comprised of separate manifolds, wherein the
inlet gas can be conducted to the RCPSA tubes, and wherein
processed purified product gas and the tail gas exiting the RCPSA
tubes can be conducted away from rotary sorber module. By suitable
arrangement of the seal plates and manifolds, a number of
individual compartments or tubes may pass through the
characteristic steps of the complete cycle at any one time.
[0105] In RCPSA, flow and pressure variations required for the
sorption/desorption cycle can change in a number of separate
increments on the order of seconds per cycle, which can smooth out
the pressure and flow rate pulsations encountered by the
compression and valving machinery. In this form, the RCPSA module
can include valving elements angularly spaced around the circular
path taken by the rotating sorption module, so that each
compartment can be successively passed to a gas flow path in the
appropriate direction and pressure to achieve one of the
incremental pressure/flow direction steps in the complete RCPSA
cycle. Example RCPSA modules and valving arrangements that can be
used according to this invention are described in U.S. Reissue
Patent Nos. RE 40,006 and RE 38,493.
[0106] Without being limited by theory, one significant advantage
of the RCPSA technology includes a highly efficient use of the
adsorbent material. The quantity of adsorbent required with RCPSA
technology is typically a fraction of that required for standard
PSA technology to achieve the same separation quantities and
qualities. RCPSA technology also tends to have a small foot print,
which allows technology to be deployed closer to the
hydroprocessing units in an efficient manner. Because of the
relatively fast cycle times, RCPSA technology can also exhibit
added capability to produce treat gas hydrogen with low CO content
in a steady manner (i.e., steady state can be achieved relatively
quickly, e.g., in less than about an hour).
Acid Gas Treating
[0107] According to an aspect of the invention, the gas stream
separated from the hydroprocessed product can be acid gas treated.
Acid gas treatment refers to treating a gas stream to remove or to
lower acid gas components. Acid gas components can include one or
more acid gases, such as those selected from the group consisting
of CO.sub.2, H.sub.2S, SO.sub.2, CS.sub.2, HCN, COS, and
mercaptans.
[0108] Acid gas treatment can preferably comprise contacting the
gas stream containing at least one of the acid gas components with
an organic solvent or an aqueous solution of an organic solvent in
a gas scrub or a liquid-liquid extraction. The solvent can be a
physical solvent or a chemical solvent. Physical solvents generally
rely on a physical absorption process. In such a process the acid
gases can dissolve in a physical solvent. Examples of physical
solvents can include, but are not limited to, cyclotetramethylene
sulfone (sulfolane) and its derivatives, aliphatic acid amides, NMP
(N-methylpyrrolidone), N-alkylated pyrrolidones and corresponding
piperidones, methanol, mixtures of dialkylethers of polyethylene
glycols (e.g., SELEXOL.RTM. from Union Carbide of Danbury, Conn.),
and combinations thereof.
[0109] Chemical solvents can tend to work on the basis of chemical
reactions in which the acid gases are converted into compounds that
are simpler to remove. Examples of such chemical solvents can
include aqueous solutions of one or more amines, preferably
alkanolamines. Preferred amines include those that form salts when
acid gases pass through a solution containing the amine. These
salts can then preferably be decomposed by heating and/or be
stripped off using steam. The amine solution can be regenerated by
heating or stripping and can be re-used. Preferred alkanolamines
can include, but are not limited to, monoethanolamine (MEA),
diethanolamine (DEA), triethanolamine (TEA), diisopropylamine
(DIPA), aminoethoxyethanol (AEE), methyldiethanolamine (MDEA), and
combinations thereof.
Reactor Type
[0110] Any reactor or catalyst arrangement suitable for
hydroprocessing the feedstock of this invention can be used. For
example, the feedstock can be provided to a hydroprocessing zone so
as to contact a fixed bed of catalyst, a fluidized bed, or an
ebullating bed. An example of one type of configuration includes a
trickle-bed operation in which a liquid feedstock trickles through
a stationary fixed bed. Another example of a reactor configuration
includes a countercurrent process, i.e., the hydrocarbon feed flows
down over a fixed catalyst bed while H.sub.2 flows in the upward
(opposite) direction.
Transportation Fuel Recovery
[0111] Light or heavy fractions of the hydroprocessed product
(typically a liquid portion of the hydroprocessed product) can be
removed to produce or recover the desired transportation fuel. In
one embodiment, separation of light or heavy components or
fractions of the hydroprocessed product can be carried out to
positively affect fuel quality, and in particular to provide at
least one jet fuel or diesel fuel having high quality
characteristics. Separation can be carried out using any
appropriate means. Fractionation or distillation may be preferred.
Atmospheric distillation, vacuum distillation, or a combination
thereof can be used.
Additional Embodiments
[0112] Additionally or alternately, the invention includes one or
more of the following embodiments.
[0113] Embodiment 1. A method for producing transportation fuel,
comprising: providing a feedstock containing lipid material and
mineral oil, wherein the lipid material is selected from the group
consisting of triglycerides, fatty acid alkyl esters, and
combinations thereof; and hydroprocessing the feedstock in a
hydroprocessing zone to produce the transportation fuel, wherein
the hydroprocessing zone is maintained at not greater than 1000
vppm CO, based on total vapor content of the hydroprocessing
zone.
[0114] Embodiment 2. The method of embodiment 1, wherein a
hydrogen-containing stream that contains not greater than 200 vppm
CO, based on total volume of the hydrogen-containing stream, is
added to the hydroprocessing zone during hydroprocessing, which
hydrogen-containing stream optionally contains greater than 60 vol
% H.sub.2, based on total volume of the hydrogen-containing
stream.
[0115] Embodiment 3. The method of embodiment 1 or embodiment 2,
wherein the hydroprocessing zone contains a CoMo or a NiMo
hydroprocessing catalyst.
[0116] Embodiment 4. The method of any of the previous embodiments,
wherein the hydroprocessing produces a hydroprocessed product
comprised of a liquid fraction and a gas fraction, and the gas
fraction is separated from the liquid fraction, with at least a
portion of the liquid fraction forming the transportation fuel,
wherein the separated gas fraction is optionally treated or
contacted with a membrane or an adsorbent to remove at least a
majority of the CO from the gas stream to form a treated gas
stream.
[0117] Embodiment 5. The method of embodiment 4, wherein (i) the
separated gas fraction is treated or contacted with an adsorbent
that is contained in a pressure swing adsorption system or a rapid
cycle pressure swing adsorption system to form the treated gas
stream, (ii) at least a portion of the treated gas stream is added
to the hydroprocessing zone during hydroprocessing, or (iii) both
(i) and (ii).
[0118] Embodiment 6. The method of embodiment 4 or embodiment 5,
wherein at least a portion of the separated gas fraction is acid
gas treated.
[0119] Embodiment 7. The method of any of the previous embodiments,
wherein (i) the feedstock includes at least 0.05 wt % lipid
material, based on total weight of the feedstock, (ii) the lipid
material portion of the feedstock is comprised of at least 20 wt %
fatty acid alkyl ester, based on total weight of the lipid material
in the feedstock, or (iii) both (i) and (ii).
[0120] Embodiment 8. A process for producing a transportation fuel,
comprising: providing a feedstock containing lipid material and
mineral oil; hydroprocessing the feedstock in a hydroprocessing
zone to produce a hydroprocessed product comprised of a liquid
fraction and a gas fraction; separating at least a portion of the
gas fraction from the hydroprocessed product; removing at least a
majority of CO contained in the separated gas fraction to form a
treated gas stream; providing at least a portion of the treated gas
stream to the hydroprocessing zone; and recovering at least a
portion of the liquid fraction as the transportation fuel.
[0121] Embodiment 9. The method of embodiment 8, wherein at least a
portion of the gas fraction separated from the hydroprocessed
product is acid gas treated prior to removing the CO.
[0122] Embodiment 10. The method of embodiment 8 or embodiment 9,
wherein the hydroprocessing zone is maintained at not greater than
1000 vppm CO, based on total vapor content of the hydroprocessing
zone.
[0123] Embodiment 11. The method of any one of embodiments 8-10,
wherein (i) the separated gas fraction is treated or contacted with
an adsorbent that is contained in a pressure swing adsorption
system or a rapid cycle pressure swing adsorption system to form
the treated gas stream, (ii) at least a portion of the treated gas
stream is added to the hydroprocessing zone during hydroprocessing,
or (iii) both (i) and (ii).
[0124] Embodiment 12. The method of any one of embodiments 8-11,
wherein the hydroprocessing zone contains a CoMo or a NiMo
hydroprocessing catalyst.
[0125] Embodiment 13. The method of any one of embodiments 8-12,
wherein (i) the feedstock includes at least 0.05 wt % lipid
material selected from the group consisting of triglycerides, fatty
acid alkyl esters, and combinations thereof, based on total weight
of the feedstock, (ii) the lipid material portion of the feedstock
is comprised of at least 20 wt % fatty acid alkyl ester, based on
total weight of the lipid material in the feedstock, or (iii) both
(i) and (ii).
EXAMPLES
Example 1
[0126] A feedstock was prepared, with about 1.5 wt % of the total
feedstock being comprised of a fatty acid methyl ester and the
remainder being a light gas oil. The feedstock was hydroprocessed
over a reactor containing about 100 cm.sup.3 of a CoMo
hydroprocessing catalyst at a liquid hourly space velocity of about
0.76 hr.sup.-1. The reaction was carried out at a reactor
temperature of about 630.degree. F. (about 322.degree. C.) and a
reactor pressure of about 230 psig (about 1.6 MPag), with the
reactor operating over a period of several days. At about 26.6-29.2
days of operation, hydrogen treat gas was added to the reactor. The
treat gas contained about 80% H.sub.2, and was added at a relative
treat gas rate (TGR) of about 370 scf/bbl (about 300 scf/bbl of
H.sub.2). The result of the run is shown in the FIGURE as Case
A.
[0127] At about 32.8-35.6 days, the treat gas was changed to
contain about 60% H.sub.2, and was added at a relative rate of
about 550 scf/bbl (about 330 scf/bbl of H.sub.2). The result of the
run is shown in the FIGURE as Case B.
[0128] Comparing Case A to Case B in the FIGURE, it can be seen
that Case B produces substantially greater CO and CO.sub.2 relative
to Case A.
Example 2
[0129] A Run 2A is performed as in Example 1, except that the
hydrogen treat gas contains 100% H.sub.2 to obtain a base case
run.
[0130] A Run 2B is performed as in Run 2A, except that the hydrogen
treat gas contains 200 vppm CO, with the remainder of the treat gas
being H.sub.2.
[0131] A Run 2C is performed as in Run 2A, except that the hydrogen
treat gas contains 1000 vppm CO, with the remainder of the treat
gas being H.sub.2.
[0132] An analysis of the gas phase of the hydroprocessed product
of Run 2B should show a reduction in catalyst activity, as compared
to Run 2A.
[0133] An analysis of the gas phase of the hydroprocessed product
of Run 2C should show a significant reduction in catalyst activity,
relative to Runs 2A and 2B.
[0134] The above Examples indicate that the H.sub.2 and/or CO
content of a treat gas to a hydroprocessing zone can significantly
impact the conversion of feedstock to fuel product when the
feedstock contains even a small amount of lipid material. In one
embodiment, a combination of membranes, adsorbents, or both can be
utilized to increase H.sub.2 purity to a desired, predetermined
amount, as well as to selectively adsorb CO to thereby reduce the
CO content of the treat gas to a desired, predetermined amount.
[0135] 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, may encompass
other embodiments not specifically enumerated herein.
* * * * *