U.S. patent application number 12/260877 was filed with the patent office on 2009-05-07 for method of upgrading heavy hydrocarbon streams to jet products.
This patent application is currently assigned to Chevron U.S.A. Inc.. Invention is credited to Cong-Yan Chen, Alexander E. Kuperman.
Application Number | 20090114566 12/260877 |
Document ID | / |
Family ID | 40587032 |
Filed Date | 2009-05-07 |
United States Patent
Application |
20090114566 |
Kind Code |
A1 |
Chen; Cong-Yan ; et
al. |
May 7, 2009 |
METHOD OF UPGRADING HEAVY HYDROCARBON STREAMS TO JET PRODUCTS
Abstract
A process of upgrading a heavy hydrocarbon feedstock comprising
contacting a heavy hydrocarbon feedstock with a catalyst in the
presence of hydrogen in a reactor system, containing the catalyst
as the only catalyst, wherein the catalyst, is prepared by
sulfiding a catalyst precursor obtained by mixing at reaction
conditions, to form a precipitate or cogel, at least a Promoter
metal compound in solution; at least a Group VIB metal compound in
solution; and, at least an organic oxygen containing ligand in
solution, and thereby producing a fuel product.
Inventors: |
Chen; Cong-Yan; (Kensington,
CA) ; Kuperman; Alexander E.; (Orinda, CA) |
Correspondence
Address: |
CHEVRON CORPORATION
P.O. BOX 6006
SAN RAMON
CA
94583-0806
US
|
Assignee: |
Chevron U.S.A. Inc.
San Ramon
CA
|
Family ID: |
40587032 |
Appl. No.: |
12/260877 |
Filed: |
October 29, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11932751 |
Oct 31, 2007 |
|
|
|
12260877 |
|
|
|
|
Current U.S.
Class: |
208/112 |
Current CPC
Class: |
C10G 45/04 20130101;
C10G 45/46 20130101; C10G 2400/08 20130101; C10G 45/60 20130101;
C10G 49/02 20130101; C10G 49/002 20130101 |
Class at
Publication: |
208/112 |
International
Class: |
C10G 47/02 20060101
C10G047/02 |
Claims
1. A process of upgrading a heavy hydrocarbon feedstock comprising:
contacting a heavy hydrocarbon feedstock with a catalyst in the
presence of hydrogen in a reactor system, containing said catalysta
as the only catalyst, wherein the catalyst, is prepared from a
catalyst of the general formula:
A.sub.v[(M.sup.P)(OH).sub.x(L).sup.n.sub.y].sub.z(M.sup.VIBO.sub.4)
wherein A is at least one of an alkali metal cation, an ammonium,
an organic ammonium and a phosphonium cation, M.sup.P is at least a
Group VIII metal, L is one or more oxygen-containing ligands,
having a neutral or negative charge wherein n.ltoreq.0, M.sup.VIB
is at least a Group VIB metal, wherein M.sup.P:M.sup.VIB has an
atomic ratio of 100:1 to 1:100, and wherein 0.ltoreq.y.ltoreq.-2/n,
0.ltoreq.x.ltoreq.2; 0.ltoreq.v.ltoreq.2, and 0.ltoreq.z; and
thereby producing a fuel product.
2. The process of claim 1 wherein the heavy hydrocarbon feedstock
comprises FCC effluent, including FCC light, medium and heavy cycle
oil; fractions of jet and diesel fuels; coker product; coal
liquefied oil; the product from the heavy oil thermal cracking
process; the product from heavy oil hydrocracking; straight run cut
from a crude unit; or mixtures thereof.
3. The process of claim 1 wherein the fuel product has a net heat
of combustion of greater than 125,000 Btu/gal.
4. The process of claim 1 wherein the catalyst is unsupported.
5. The process of claim 1 wherein the catalyst is supported.
6. The process of claim 1 wherein the freezing point of the fuel
product is below -40 degrees Celsius.
7. The process of claim 1 wherein the smoke point of the fuel
product is greater than 18 mm.
8. The process of claim 1 wherein the flash point of the fuel
product is greater than 38 degrees Celsius.
9. The process of claim 1 wherein the density of the fuel product
at 20 degrees Celsius is equal to or below 0.840 g/cc.
10. The process of claim 1 wherein the viscosity of the fuel
product at -20 degrees Celsius is below 8 cSt.
11. The process of claim 1 wherein the fuel product is a jet fuel
product.
12. A process of upgrading a heavy hydrocarbon feedstock comprising
contacting a heavy hydrocarbon feedstock with a catalyst in the
presence of hydrogen in a reactor system, at hydroprocessing
conditions, containing said catalyst as the only catalyst, wherein
the catalyst, is prepared by sulfiding a catalyst precursor
obtained by mixing at reaction conditions, to form a precipitate or
cogel, at least a Promoter metal compound in solution; at least a
Group VIB metal compound in solution; and, at least an organic
oxygen containing ligand in solution, and thereby producing a fuel
product.
13. The process of claim 12 wherein the heavy hydrocarbon feedstock
comprises FCC effluent, including FCC light, medium and heavy cycle
oil; fractions of jet and diesel fuels; coker product; coal
liquefied oil; the product from the heavy oil thermal cracking
process; the product from heavy oil hydrocracking; straight run cut
from a crude unit; or mixtures thereof.
14. The process of claim 12 wherein the fuel product has a net heat
of combustion of greater than 125,000 Btu/gal.
15. The process of claim 12 wherein the catalyst is
unsupported.
16. The process of claim 12 wherein the catalyst is supported.
17. The process of claim 12 wherein the freezing point of the fuel
product is below -40 degrees Celsius.
18. The process of claim 12 wherein the smoke point of the fuel
product is greater than 8 mm.
19. The process of claim 12 wherein the flash point of the fuel
product is greater than 38 degrees Celsius.
20. The process of claim 12 wherein the density of the fuel product
at 20 degrees Celsius is equal to or below 0.840 g/cc.
21. The process of claim 12 wherein the fuel product is a jet fuel
product.
22. A product prepared by the process of claim 1.
23. A product prepared by the process of claim 12.
24. The process of claim 1 wherein the feedstock comprises at least
20 wt. % ring-containing hydrocarbon compounds comprising aromatic
moieties, naphthenic moieties or both.
25. The process of claim 4 wherein the feedstock comprises at least
20 wt % ring-containing hydrocarbon compounds comprising aromatic
moieties, naphthenic moieties or both.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit under 35 USC 120 of U.S.
application Ser. No. 11/932,751 with a filing date of Oct. 31,
2007. This application claims priority to and benefits from the
foregoing, the disclosure of which are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a hydroconversion process
wherein a hydrocarbon feed comprising aromatic compounds is
contacted with hydrogen in the presence of a catalyst composition
which catalyst composition comprises at least one Group VIII metal
and at least one Group VIB metal. Specifically, the present
invention is directed to a process for converting heavy
hydrocarbonaceous feeds to jet products using a single catalyst
system.
BACKGROUND OF THE INVENTION
[0003] Heavy hydrocarbon streams, such as FCC Light Cycle Oil
("LCO"), Medium Cycle Oil ("MCO"), and Heavy Cycle Oil ("HCO"),
have a relatively low value. Typically, such hydrocarbon streams
are upgraded through hydroconversion including hydrotreating and/or
hydrocracking.
[0004] Hydrotreating catalysts are well known in the art.
Conventional hydrotreating catalysts comprise at least one Group
VIII metal component and/or at least one Group VIB metal component
either as a bulk unsupported catalyst or, more commonly, as a
catalyst supported on a refractory oxide support. The Group VIII
metal component is typically based on a non-noble metal, such as
nickel (Ni) and/or cobalt (Co). Group VIB metal components include
those based on molybdenum (Mo) and tungsten (W). The most commonly
applied refractory oxide support materials are inorganic oxides
such as silica, alumina and silica-alumina. Examples of
conventional hydrotreating catalyst are NiMo/alumina, CoMo/alumina
and NiW/silica-alumina. In some cases, platinum and/or palladium
containing catalysts may be employed.
[0005] Hydrotreating catalysts are normally used in processes
wherein a hydrocarbon feed is contacted with hydrogen to reduce its
content of aromatic compounds, sulfur compounds, and/or nitrogen
compounds. Typically, hydrotreating processes wherein reduction of
the aromatics content is the main purpose are referred to as
hydrogenation or hydrofinishing processes, while processes
predominantly focusing on reducing sulfur and/or nitrogen content
are referred to as hydrodesulfurization and hydrodenitrogenation,
respectively. Traditionally, the term "hydrotreating" is used to
describe hydrodesulfurization and hydrodenitrogenation while the
term "hydrofinishing" is used to describe the hydrogenation of
aromatics. The present invention follows this tradition of
terminologies. Typically, hydrocracking converts feed to lighter
products such as naphtha or gas via cracking and dealkylation as
well as to low volumetric energy density components via unselective
ring opening. One disadvantage of hydrocracking is that it leads to
a higher H2 consumption due to cracking, dealkylation and
unselective ring opening. The present invention avoids these
disadvantages while producing jet products which not only meet the
requirements of the jet specifications but also possess high
volumetric energy density.
[0006] The present invention is directed to a method of upgrading
heavy hydrocarbon feedstocks with an unsupported catalyst in a
fixed bed reactor system. Specifically, the method of the present
invention is directed to a method of upgrading heavy hydrocarbon
feedstocks to jet products with high volumetric energy density.
DESCRIPTION OF THE RELATED ART
[0007] Marmo, U.S. Pat. No. 4,162,961 discloses a cycle oil that is
hydrogenated under conditions such that the product of the
hydrogenation process can be fractionated.
[0008] Myers et al., U.S. Pat. No. 4,619,759 discloses the
catalytic hydrotreatment of a mixture comprising a resid and a
light cycle oil that is carried out in a multiple catalyst bed in
which the portion of the catalyst bed with which the feedstock is
first contacted contains a catalyst which comprises alumina,
cobalt, and molybdenum and the second portion of the catalyst bed
through which the feedstock is passed after passing through the
first portion contains a catalyst comprising alumina to which
molybdenum and nickel have been added.
[0009] Kirker et al., U.S. Pat. No. 5,219,814 discloses a moderate
pressure hydrocracking process in which highly aromatic,
substantially dealkylated feedstock is processed to high octane
gasoline and low sulfur distillate by hydrocracking over a
catalyst, preferably comprising ultrastable Y and Group VIII metal
and a Group VI metal, in which the amount of the Group VIII metal
content is incorporated at specified proportion to the framework
aluminum content of the ultrastable Y component.
[0010] Kalnes, U.S. Pat. No. 7,005,057 discloses a catalytic
hydrocracking process for the production of ultra low sulfur diesel
wherein a hydrocarbonaceous feedstock is hydrocracked at elevated
temperature and pressure to obtain conversion to diesel boiling
range hydrocarbons.
[0011] Barre et al., U.S. Pat. No. 6,444,865 discloses a catalyst,
which comprises from 0.1 to 15 wt % of noble metal selected from
one or more of platinum, palladium, and iridium, from 2 to 40 wt %
of manganese and/or rhenium supported on an acidic carrier, used in
a process wherein a hydrocarbon feedstock comprising aromatic
compounds is contacted with the catalyst at elevated temperature in
the presence hydrogen.
[0012] Barre et al., U.S. Pat. No. 5,868,921 discloses a
hydrocarbon distillate fraction that is hydrotreated in a single
stage by passing the distillate fraction downwardly over a stacked
bed of two hydrotreating catalysts.
[0013] Fujukawa et al., U.S. Pat. No. 6,821,412 discloses a
catalyst for hydrotreatment of gas oil containing defined amounts
of platinum, palladium and in support of an inorganic oxide
containing a crystalline alumina having a crystallite diameter of
20 to 40 .ANG.. Also disclosed is a method for hydrotreating gas
oil containing an aromatic compound in the presence of the above
catalyst at defined conditions.
[0014] Kirker et al., U.S. Pat. No. 4,968,402 discloses a one stage
process for producing high octane gasoline from a highly aromatic
hydrocarbon feedstock.
[0015] Brown et al., U.S. Pat. No. 5,520,799 discloses a process
for upgrading distillate feeds. Hydroprocessing catalyst is placed
in a reaction zone, which is usually a fixed bed reactor under
reactive conditions and low aromatic diesel and jet fuel are
produced.
[0016] Soled et al., U.S. Pat. No. 6,162,350 discloses a slurry
hydroprocessing process for upgrading hydrocarbon feedstock with a
bulk mixed metal catalyst preferentially comprised of
Ni--Mo--W.
[0017] Haluska et al., U.S. Pat. No. 6,755,963 discloses a slurry
hydroprocessing process for upgrading hydrocarbon resid feedstock
with a bulk mixed metal catalyst comprised of one or more Group
VIII metals and one or more Group VIB metals.
[0018] Riley et al., U.S. Pat. No. 6,582,590 discloses a multistage
slurry hydroprocessing process for upgrading hydrocarbon feedstock
with a bulk mixed metal catalyst comprised of one or more Group
VIII metals and at least two Group VIB metals.
[0019] Riley et al., U.S. Pat. No. 7,229,548 discloses a slurry
hydroprocessing process for upgrading a naphtha feedstock to a
naphtha product with less than about 10 wppm of nitrogen and less
than about 15 wppm sulfur using a bulk mixed metal catalyst
comprised of one or more Group VIII metals and at least two Group
VIB metals.
[0020] Riley et al., U.S. Pat. No. 6,929,738 discloses a two stage
slurry hydroprocessing process for hydrodesulfurization of high
sulfur (greater than about 3,000 ppm sulfur) distillates with a
bulk mixed metal catalyst comprised of one or more Group VIII
metals and at least two Group VIB metals.
[0021] Hou et al., U.S. Pat. No. 6,712,955 and Riley et al., U.S.
Pat. No. 6,783,663 discloses a slurry hydroprocessing process for
upgrading hydrocarbon feedstock with a bulk mixed metal catalyst
comprised of one or more Group VIII metals and at least two Group
VIB metals.
[0022] Demmin et al., U.S. Pat. No. 6,620,313 discloses a Ni--Mo--W
catalyst used in a multi step process to hydroprocess a raffinate
feedstock.
SUMMARY OF THE INVENTION
[0023] In one embodiment of the invention, there is provided a
process for upgrading hydrocarbon feedstocks, which process
comprises contacting a heavy hydrocarbon feedstock with a catalyst
in the presence of hydrogen in a reactor system, containing said
catalyst as the only catalyst, wherein the catalyst, is prepared
from a catalyst of the general formula:
A.sub.v[(M.sup.P)(OH).sub.x(L).sup.n.sub.y].sub.z(M.sup.VIBO.sub.4)
wherein [0024] A is at least one of an alkali metal cation, an
ammonium, an organic ammonium and a phosphonium cation, [0025]
M.sup.P is at least a Group VIII metal, [0026] X is at least an
organic oxygen-containing ligand, [0027] M.sup.VIB is at least a
Group VIB metal, [0028] and wherein M.sup.P:M.sup.VIB has an atomic
ratio of 100:1 to 1:100; and thereby producing a fuel product.
[0029] In one embodiment of the present invention, there is
provided a process of upgrading a heavy hydrocarbon feedstock
comprising contacting a heavy hydrocarbon feedstock with a catalyst
in the presence of hydrogen in a reactor system, at hydroprocessing
conditions, containing said catalyst as the only catalyst, wherein
the catalyst, is prepared by sulfiding a catalyst precursor
obtained by mixing at reaction conditions, to form a precipitate or
cogel, at least a Promoter metal compound in solution; at least a
Group VIB metal compound in solution; and, at least an organic
oxygen containing ligand in solution, and thereby producing a fuel
product.
[0030] The process according to the invention can achieve increased
hydrocarbon productivity through an increase in the conversion of
lower value hydrocarbon streams to higher quality products in a
single reactor system.
[0031] The process of the invention is desirably practiced with a
light cycle oil (LCO) feedstock and a catalyst comprising nickel,
molybdenum, and tungsten to produce jet products.
DETAILED DESCRIPTION OF THE INVENTION
[0032] While the invention is susceptible to various modifications
and alternative forms, specific embodiments thereof are herein
described in detail. It should be understood, however, that the
description herein of specific embodiments is not intended to limit
the invention to the particular forms disclosed, but on the
contrary, the intention is to cover all modifications, equivalents,
and alternatives falling within the spirit and scope of the
invention as defined by the appended claims.
Definitions
[0033] FCC--The term "FCC" refers to fluid catalytic crack -er,
-ing, or -ed.
[0034] As used herein, the terms "feedstock" and "feedstream" are
interchangeable.
[0035] As used herein, "hydroprocessing" is meant any process that
is carried out in the presence of hydrogen, including, but not
limited to, hydrogenation, hydrofinishing, hydrotreating,
hydrodesulphurization, hydrodenitrogenation, hydrodemetallation,
hydrodearomatization, hydroisomerization, hydrodewaxing and
hydrocracking including selective hydro-ring-opening. Depending on
the type of hydroprocessing and the reaction conditions, the
products of hydroprocessing may show improved viscosities,
viscosity indices, saturates content, low temperature properties,
volatilities and depolarization, etc.
[0036] Energy density--refers to the heat of combustion of a fuel,
which is released during its combustion. The amount of heat
released depends on whether the water formed during combustion
remains in the vapor phase or is condensed to a liquid. If the
water is condensed to the liquid phase, it gives up its heat of
vaporization in the process. In this case, the released heat is
called gross heat of combustion. The net heat of combustion is
lower than the gross heat of combustion because the water remains
in the gaseous phase (water vapor). The net heat of combustion is
the appropriate value for comparing fuels since engines exhaust
water as vapor. The net volumetric energy density describes the net
energy density of a fuel on the volumetric basis and is often given
in Btu per gallon, for example, 125,000 Btu per gallon for a jet
fuel and 130,000 Btu per gallon for a diesel.
[0037] LHSV--refers to liquid hourly space velocity, which is the
volumetric rate of the liquid feed (i.e., the volume of the liquid
feed at 60.degree. F. per hour) divided by the volume of the
catalyst, and is given in hr.sup.-1.
[0038] The Periodic Table referred to herein is the Table approved
by IUPAC and the U.S. National Bureau of Standards, an example is
the Periodic Table of the Elements by Los Alamos National
Laboratory's Chemistry Division of October 2001.
[0039] The term "Group VIB metal" refers to chromium, molybdenum,
tungsten, and combinations thereof in their elemental, compound, or
ionic form.
[0040] The term "Group IIB metal" refers to zinc, cadmium, mercury
and combinations thereof in their elemental, compound, or ionic
form.
[0041] The term "Group IIA metal" refers to beryllium, magnesium,
calcium, strontium, barium, radium, and combinations thereof in
their elemental, compound, or ionic form.
[0042] The term "Group IVA metal" refers to germanium, tin or lead,
and combinations thereof in their elemental, compound, or ionic
form.
[0043] The term "Group VIII metal" refers to iron, cobalt, nickel,
ruthenium, rhenium, palladium, osmium, iridium, platinum, and
combinations thereof in their elemental, compound, or ionic
form.
[0044] As used herein, the term MP, or "Promoter metal" means any
of: at least one of Group VIII metals; at least one of Group IIB
metals; at least one of Group IIA metals; at least of one of Group
IVA metals; a combination of different Group IIB metals; a
combination of different Group IIA metals; a combination of
different Group IVA, IIA, IIB, or VIII metals; a combination of at
least a Group IIB metal and at least a Group IVA metal; a
combination of at least a Group IIB metal and at least a group VIII
metal; a combination of at least a Group IVA metal and at least a
group VIII metal; a combination of at least a Group IIB metal, at
least a Group IVA metal and at least a group VIII metal; and
combinations at least two metals, with the individual metal being
from any of Group VIII, Group IIB, Group IIA, and Group IVA
metals.
[0045] As used herein, the phrases "one or more of" or "at least
one of" when used to preface several elements or classes of
elements such as X, Y and Z or X1-Xn, Y1-Yn and Z1-Zn, is intended
to refer to a single element selected from X or Y or Z, a
combination of elements selected from the same common class (such
as X1 and X2), as well as a combination of elements selected from
different classes (such as X1, Y2 and Zn).
[0046] As used herein, "hydroconversion" or "hydroprocessing" is
meant any process that is carried out in the presence of hydrogen,
including, but not limited to, methanation, water gas shift
reactions, hydrogenation, hydrotreating, hydrodesulphurization,
hydrodenitrogenation, hydrodemetallation, hydrodearomatization,
hydroisomerization, hydrodewaxing and hydrocracking including
selective hydrocracking. Depending on the type of hydroprocessing
and the reaction conditions, the products of hydroprocessing can
show improved viscosities, viscosity indices, saturates content,
low temperature properties, volatilities and depolarization,
etc.
[0047] As used herein, the term "catalyst precursor" refers to a
compound containing at least a Promoter metal (e.g., one or more
Group VIII metals, one or more Group IIB metals, one or more Group
IIA metals, one or more Group IVA metals, and combinations
thereof), at least a Group VIB metal; at least a hydroxide; and one
or more organic oxygen-containing ligands, and which compound can
be catalytically active after sulfidation as a hydroprocessing
catalyst.
[0048] As used herein, the term "charge-neutral" refers to the fact
that the catalyst precursor carries no net positive or negative
charge. The term "charge-neutral catalyst precursor" can sometimes
be referred to simply as "catalyst precursor."
[0049] As used herein, the term "ammonium" refers to a cation with
the chemical formula NH4+ or to organic nitrogen containing
cations, such as organic quaternary amines.
[0050] As used herein, the term "phosphonium" refers to a cation
with the chemical formula PH4+ or to organic phosphorus-containing
cations.
[0051] The term oxoanion refers to monomeric oxoanions and
polyoxometallates. As used herein, the term "mixture" refers to a
physical combination of two or more substances. The "mixture" can
be homogeneous or heterogeneous and in any physical state or
combination of physical states.
[0052] The term "reagent" refers to a raw material that can be used
in the manufacture of the catalyst precursor of the invention. When
used in conjunction with a metal, the term "metal" does not mean
that the reagent is in the metallic form, but is present as a metal
compound.
[0053] As used herein the term "carboxylate" refers to any compound
containing a carboxylate or carboxylic acid group in the
deprotonated or protonated state.
[0054] As used herein, the term "ligand" may be used
interchangeably with "chelating agent" (or chelator, or chelant),
referring to an additive that combines with metal ions, e.g., Group
VIB and/or Promoter metals, forming a larger complex, e.g., a
catalyst precursor.
[0055] As used herein, the term "organic" means containing carbon,
and wherein the carbon can be from biological or non-biological
sources.
[0056] As used herein, the term "organic oxygen-containing ligand"
refers to any compound comprising at least one carbon atom, at
least one oxygen atom, and at least one hydrogen atom wherein said
oxygen atom has one or more electron pairs available for
co-ordination to the Promoter metal(s) or Group VIB metal ion. In
one embodiment, the oxygen atom is negatively charged at the pH of
the reaction. Examples of organic oxygen-containing ligands
include, but are not limited to, carboxylic acids, carboxylates,
aldehydes, ketones, the enolate forms of aldehydes, the enolate
forms of ketones, hemiacetals, and the oxo anions of
hemiacetals.
[0057] The term "cogel" refers to a hydroxide co-precipitate (or
precipitate) of at least two metals containing a water rich phase.
"Cogelation" refers to the process of forming a cogel or a
precipitate.
A. Overview
[0058] In one embodiment, the present invention is directed to a
process of upgrading heavy hydrocarbons comprising: [0059] (a)
Preparing a catalyst by sulfidation of a catalyst precursor in
which the catalyst precursor comprises at least one Promoter metal
hydroxide, at least one Group VIB metal oxoanion, and at least one
oxygen containing co-ordinating ligand; and [0060] (b) reacting a
heavy hydrocarbon feedstream with the catalyst in the presence of
hydrogen in a fixed bed reactor;
B. Feed
[0061] Heavy hydrocarbon feedstock may be upgraded to a product
having a boiling point range within jet boiling point ranges. The
hydrocarbon feedstock comprises FCC effluent, including FCC light,
medium and heavy cycle oil; fractions of jet and diesel fuels;
coker product; coal liquefied oil; the product from the heavy oil
thermal cracking process; the product from heavy oil hydrotreating
and/or hydrocracking; straight run cut from a crude unit; or
mixtures thereof, and having a major portion of the feedstock
having a boiling range of from about 250.degree. F. to about
1200.degree. F., and preferably from about 300.degree. F. to about
1000.degree. F. The term "major portion" as used in this
specification and the appended claims, shall mean at least 50 wt
%.
[0062] Typically, the feedstock may comprise at least 20 wt %
ring-containing hydrocarbon compounds comprising aromatic moieties,
naphthenic moieties or both, up to 3 wt % sulfur and up to 1 wt %
nitrogen. Preferably, the feedstock may comprise at least 40 wt %
ring-containing hydrocarbon compounds. More preferred, the
feedstock may comprise at least 60 wt % ring-containing hydrocarbon
compounds.
C. Catalyst
[0063] In one embodiment of the present invention, the catalyst
employed is prepared from a catalyst precursor which may be
sulfided thereby producing an active catalyst which is used to
produce the jet fuel product of the present invention.
[0064] Catalyst Precursor Formula: n one embodiment, the
charge-neutral catalyst precursor composition is of the general
formula Av[(MP)(OH)x(L)ny]z (MVIBO4), wherein:
[0065] A is one or more monovalent cationic species. In one
embodiment, A is at least one of an alkali metal cation, an
ammonium, an organic ammonium and a phosphonium cation; MP is at
least a Promoter metal with an oxidation state P of either +2 or +4
depending on the Promoter metal(s) being employed. MP is selected
from Group VIII, Group IIB, Group IIA, Group IVA and combinations
thereof. In one embodiment wherein MP is at least a Group VIII
metal, MP has an oxidation state P of +2.
[0066] L is one or more oxygen-containing ligands, and L has a
neutral or negative charge n<=0;
[0067] MVIB is at least a Group VIB metal having an oxidation state
of +6;
[0068] MP:MVIB has an atomic ratio between 100:1 and 1:100;
v-2+P*z-x*z+n*y*z=0; and 0.ltoreq.y.ltoreq.-P/n;
0.ltoreq.x.ltoreq.P; 0.ltoreq.v.ltoreq.2; 0.ltoreq.z.
[0069] In one embodiment, L is selected from carboxylates,
carboxylic acids, aldehydes, ketones, the enolate forms of
aldehydes, the enolate forms of ketones, and hemiacetals, and
combinations thereof.
[0070] In one embodiment, A is selected from monovalent cations
such as NH4+, other quaternary ammonium ions, organic phosphonium
cations, alkali metal cations, and combinations thereof.
[0071] In one embodiment where both molybdenum and tungsten are
used as the Group VIB metals, the molybdenum to tungsten atomic
ratio (Mo:W) is in the range of about 10:1 to 1:10. In another
embodiment, the ratio of Mo:W is between about 1:1 and 1:5. In an
embodiment where molybdenum and tungsten are used as the Group VIB
metals, the charge-neutral catalyst precursor is of the formula
Av[(MP)(OH)x(L)ny]z(MotWt'O4). In yet another embodiment, where
molybdenum and tungsten are used as the Group VIB metals, chromium
can be substituted for some or all of the tungsten with the ratio
of (Cr+W):Mo is in the range of about 10:1 to 1:10. In another
embodiment, the ratio of (Cr+W):Mo is between 1:1 and 1:5. In an
embodiment where molybdenum, tungsten, and chromium are the Group
VIB metals, the charge-neutral catalyst precursor is of the formula
Av[(MP)(OH)x(L)ny]z(MotWt'Crt''O4).
[0072] In one embodiment, the Promoter metal MP is at least a Group
VIII metal with MP having an oxidation state of +2 and the catalyst
precursor of the formula Av[(MP)(OH)x(L)ny]z(MVIBO4) to have
(v-2+2z-x*z+n*y*z)=0.
[0073] In one embodiment, the Promoter metal MP is a mixture of two
Group VIII metals such as Ni and Co. In yet another embodiment, MP
is a combination of three metals such as Ni, Co and Fe.
[0074] In one embodiment wherein MP is a mixture of two group IIB
metals such as Zn and Cd, the charge-neutral catalyst precursor is
of the formula Av[(ZnaCda')(OH)x(L)y]z(MVIBO4). In yet another
embodiment, MP is a combination of three metals such as Zn, Cd and
Hg, the charge-neutral catalyst precursor is of the formula
Av[(ZnaCda'Hga'')(OH)x(L)ny]z(MVIBO4).
[0075] In one embodiment wherein MP is a mixture of two Group IIA
metals such as Mg and Ca, the charge-neutral catalyst precursor is
of the formula Av[(Mgb,Cab')(OH)x(L)ny]z(MVIBO4). In another
embodiment wherein MP is a combination of three Group IIA metals
such as Mg, Ca and Ba, the charge-neutral catalyst precursor is of
the formula Av[(MgbCab'Bab'')(OH)x(L)ny]z(MVIBO4).
[0076] Promoter Metal Component MP: In one embodiment, the Promoter
metal (MP) compound is in a solution state, with the whole amount
of the Promoter metal compound dissolved in a liquid to form a
homogeneous solution. In another embodiment, the Promoter metal is
partly present as a solid and partly dissolved in the liquid. In a
third embodiment, it is completely in the solid state.
[0077] The Promoter metal compound MP can be a metal salt or
mixtures of metal salts selected from nitrates, hydrated nitrates,
chlorides, hydrated chlorides, sulphates, hydrated sulphates,
formates, acetates, hypophosphites, and mixtures thereof.
[0078] In one embodiment, the Promoter metal MP is a nickel
compound which is at least partly in the solid state, e.g., a
water-insoluble nickel compound such as nickel carbonate, nickel
hydroxide, nickel phosphate, nickel phosphite, nickel formate,
nickel sulphide, nickel molybdate, nickel tungstate, nickel oxide,
nickel alloys such as nickel-molybdenum alloys, Raney nickel, or
mixtures thereof.
[0079] In one embodiment, the Promoter metal MP is selected from
the group of IIB and VIA metals such as zinc, cadmium, mercury,
germanium, tin or lead, and combinations thereof, in their
elemental, compound, or ionic form. In yet another embodiment, the
Promoter metal MP further comprises at least one of Ni, Co, Fe and
combinations thereof, in their elemental, compound, or ionic
form.
[0080] In one embodiment, the Promoter metal compound is a zinc
compound which is at least partly in the solid state, e.g., a zinc
compound poorly soluble in water such as zinc carbonate, zinc
hydroxide, zinc phosphate, zinc phosphite, zinc formate, zinc
sulphide, zinc molybdate, zinc tungstate, zinc oxide, zinc alloys
such as zinc-molybdenum alloys.
[0081] In an embodiment, the Promoter metal is a Group IIA metal
compound, selected from the group of magnesium, calcium, strontium
and barium compounds which are at least partly in the solid state,
e.g., a water-insoluble compound such as a carbonate, hydroxide,
phosphate, phosphite, sulphide, molybdate, tungstate, oxide, or
mixtures thereof.
[0082] In one embodiment, the Promoter metal compound is a tin
compound which is at least partly in the solid state, e.g., a tin
compound poorly soluble in water such as stannic acid, tin
phosphate, zinc formate, tin acetate, tin molybdate, tin tungstate,
tin oxide, tin alloys such as tin-molybdenum alloys.
Group VIB Metal Component:
[0083] The Group VIB metal (MVIB) compound can be added in the
solid, partially dissolved, or solution state. In one embodiment,
the Group VIB metal compound is selected from molybdenum, chromium,
tungsten components, and combinations thereof. Examples of such
compounds include, but are not limited to, alkali metal, alkaline
earth, or ammonium metallates of molybdenum, tungsten, or chromium,
(e.g., ammonium tungstate, meta-, para-, hexa-, or polytungstate,
ammonium chromate, ammonium molybdate, iso-, peroxo-, di-, tri-,
tetra-, hepta-, octa-, or tetradecamolybdate, alkali metal
heptamolybdates, alkali metal orthomolybdates, or alkali metal
isomolybdates), ammonium salts of phosphomolybdic acids, ammonium
salts of phosphotunstic acids, ammonium salts of phosphochromic
acids, molybdenum (di- and tri) oxide, tungsten (di- and tri)
oxide, chromium or chromic oxide, molybdenum carbide, molybdenum
nitride, aluminum molybdate, molybdic acid, chromic acid, tungstic
acid, Mo--P heteropolyanion compounds, Wo--Si heteropolyanion
compounds, W--P heteropolyanion compounds. W--Si heteropolyanion
compounds, Ni--Mo--W heteropolyanion compounds. Co--Mo--W
heteropolyanion compounds, or mixtures thereof, added in the solid,
partially dissolved, or solute state.
Chelating Agent (Ligand) L:
[0084] In one embodiment, the catalyst precursor composition
comprises at least a non-toxic organic oxygen containing ligand
with an LD50 rate (as single oral dose to rats) of greater than 500
mg/Kg. In a second embodiment, the organic oxygen containing ligand
L has an LD50 rate of >700 mg/Kg. In a third embodiment, organic
oxygen containing chelating agent has an LD50 rate of >1000
mg/Kg. As used herein, the term "non-toxic" means the ligand has an
LD50 rate (as single oral dose to rats) of greater than 500 mg/Kg.
As used herein the term "at least an organic oxygen containing
ligand" means the composition may have more than one organic oxygen
containing ligand in some embodiments, and some of the organic
oxygen containing ligand may have an LD50 rate of <500 mg/Kg,
but at least one of the organic oxygen containing ligands has an
LD50 rate of >500 mg/Kg.
[0085] In one embodiment, the oxygen-containing chelating agent L
is selected from the group of non-toxic organic acid addition salts
such as formic acid, acetic acid, propionic acid, maleic acid,
fumaric acid, succinic acid, tartaric acid, citric acid, oxalic
acid, glyoxylic acid, aspartic acid, alkane sulfonic acids such as
methane sulfonic acid and ethane sulfonic acid, aryl sulfonic acids
such as benzene sulfonic acid and p-toluene sulfonic acid and
arylcarboxylic acids such as benzoic acid. In one embodiment, the
oxygen-containing chelating agent L is maleic acid (LD of 708
mg/kg).
[0086] In one another embodiment, the non-toxic chelating agent L
is selected from the group of glycolic acid (having an LD50 of 1950
mg/kg), lactic acid (LD50 of 3543 mg/kg), tartaric acid (LD50 of
7500 mg/kg), malic acid (LD50 of 1600 mg/kg), citric acid (LD50 of
5040 mg/kg), gluconic acid (LD50 of 10380 mg/kg), methoxy-acetic
acid (LD50 of 3200 mg/kg), ethoxy-acetic acid (LD50 of 1292 mg/kg),
malonic acid (LD 50 of 1310 mg/Kg), succinic acid (LD 50 of 500
mg/kg), fumaric acid (LD50 of 10700 mg/kg), and glyoxylic (LD 50 of
3000 mg/kg). In yet embodiment the non-toxic chelating agent is
selected from the group of organic sulfur compounds including but
not limited to mercapto-succinic acid (LD 50 of 800 mg/kg) and
thio-diglycolic acid (LD 50 of 500 mg/kg).
[0087] In yet another the oxygen containing ligand L is a
carboxylate containing compound. In one embodiment, the carboxylate
compound contains one or more carboxylate functional groups. In yet
another embodiment, the carboxylate compound comprises
monocarboxylates including, but not limited to, formate, acetate,
propionate, butyrate, pentanoate, and hexanoate and dicarboxylates
including, but not limited to, oxalate, malonate, succinate,
glutarate, adipate, malate, maleate, or combinations thereof. In a
fourth embodiment, the carboxylate compound comprises maleate.
[0088] The organic oxygen containing ligands can be mixed with the
Promoter metal containing solution or mixture, the Group VIB metal
containing solution or mixture, or a combination of the Promoter
metal and Group VIB metal containing precipitates, solutions, or
mixtures. The organic oxygen containing ligands can be in a
solution state, with the whole amount of the organic oxygen
containing ligands dissolved in a liquid such as water. The organic
oxygen containing ligands can be partially dissolved and partially
in the solid state during mixing with the Promoter metal(s), Group
VIB metal(s), or combinations thereof.
Methods for Making Hydroprocessing Catalyst Precursor:
[0089] The preparation method allows systematic varying of the
composition and structure of the catalyst precursor by controlling
the relative amounts of the elements, the types of the reagents,
and the length and severity of the various reactions and reaction
steps.
[0090] The order of addition of the reagents used in forming the
catalyst precursor may be in various ways. For example, organic
oxygen containing ligand can be combined with a mixture of Promoter
metals and Group VIB metals prior to precipitation or cogelation.
The organic oxygen containing ligand can be mixed with a solution
of a Promoter metal, and then added to a solution of one or more
Group VIB metals. The organic oxygen containing ligand can be mixed
with a solution of one or more Group VIB metals and added to a
solution of one or more Promoter metals.
Forming a Precipitate or Cogel with Group VIB/Promoter Metals:
[0091] In one embodiment of the process, the first step is a
precipitation or cogelation step, which involves reacting in a
mixture the Promoter metal component in solution and the Group VIB
metal component in solution to obtain a precipitate or cogel. The
precipitation or cogelation is carried out at a temperature and pH
which the Promoter metal compound and the Group VIB metal compound
precipitate or form a cogel. An organic oxygen containing ligand in
solution or at least partially in solution is then combined with
the precipitate or cogel to form an embodiment of the catalyst
precursor.
[0092] In an embodiment, the temperature at which the catalyst
precursor is formed is between 50-150.degree. C. If the temperature
is below the boiling point of the protic liquid, such as
100.degree. C. in the case of water, the process is generally
carried out at atmospheric pressure. Above this temperature, the
reaction is generally carried out at increased pressure, such as in
an autoclave. In one embodiment, the catalyst precursor is formed
at a pressure of between about 0 to 3000 psig. In a second
embodiment, the catalyst precursor is formed at a pressure of
between about 100 to 1000 psig.
[0093] The pH of the mixture can be changed to increase or decrease
the rate of precipitation or cogelation, depending on the desired
characteristics of the product. In one embodiment, the mixture is
kept at its natural pH during the reaction step(s). In another
embodiment, the pH is maintained in the range of between about
0-12. In another embodiment, the pH is maintained in the range of
between about 4-10. In a further embodiment, the pH is maintained
in the range of between about 7-10. Changing the pH can be done by
adding base or acid to the reaction mixture, or adding compounds,
which decompose upon temperature increase into hydroxide ions or
H.sup.+ ions that respectively increase or decrease the pH.
Examples include urea, nitrites, ammonium hydroxide, mineral acids,
organic acids, mineral bases, and organic bases.
[0094] In one embodiment, the reaction of Promoter metal
component(s) is carried out with water-soluble metal salts, e.g.,
zinc, molybdenum and tungsten metal salts. The solution can further
comprise other Promoter metal component(s), e.g., cadmium or
mercury compounds such as Cd(NO.sub.3).sub.2 or
(CH.sub.3CO.sub.2).sub.2Cd, Group VIII metal components including
cobalt or iron compounds such as Co(NO.sub.3).sub.2 or
(CH.sub.3CO.sub.2).sub.2Co, as well as other Group VIB metal
component(s) such as chromium.
[0095] In one embodiment, the reaction of Promoter metal
component(s) is carried out with water-soluble tin, molybdenum and
tungsten metal salts. The solution can further comprise other Group
IVA metal component(s), e.g. lead compounds such as
Pb(NO.sub.3).sub.4 or (CH.sub.3CO.sub.2).sub.2Pb, as well as other
Group VIB metal compounds such as chromium compounds.
[0096] The reaction is carried with the appropriate metal salts
resulting in precipitate or cogel combinations of
nickel/molybdenum/tungsten, cobalt/molybdenum/tungsten,
nickel/molybdenum, nickel/tungsten, cobalt/molybdenum,
cobalt/tungsten, or nickel/cobalt/molybdenum/tungsten. An organic
oxygen containing ligand can be added prior to or after
precipitation or cogelation of the Group VIII and/or Group VIB
metal components.
[0097] The metal precursors can be added to the reaction mixture in
solution, suspension or a combination thereof. If soluble salts are
added as such, they will dissolve in the reaction mixture and
subsequently be precipitated or cogeled. The solution can be heated
optionally under vacuum to effect precipitation and evaporation of
the water.
[0098] After precipitation or cogelation, the catalyst precursor
can be dried to remove water. Drying can be performed under
atmospheric conditions or under an inert atmosphere such as
nitrogen, argon, or vacuum. Drying can be effected at a temperature
sufficient to remove water but not removal of organic components.
Preferably drying is performed at about 120.degree. C. until a
constant weight of the catalyst precursor is reached.
Characterization of the Catalyst Precursor:
[0099] Characterization of the charge-neutral catalyst precursor
can be performed using techniques known in the art, including, but
not limited to, powder x-ray diffraction (PXRD), elemental
analysis, surface area measurements, average pore size
distribution, average pore volume. Porosity and surface area
measurements can be performed using BJH analysis under B.E.T.
nitrogen adsorption conditions.
Characteristics of the Catalyst Precursor:
[0100] In one embodiment, the catalyst precursor has an average
pore volume of 0.05-5 ml/g as determined by nitrogen adsorption. In
another embodiment, the average pore volume is 0.1-4 ml/g. In a
third embodiment, the average pore volume is 0.1-3 ml/g.
[0101] In one embodiment, the catalyst precursor has a surface area
of at least 10 m.sup.2/g. In a second embodiment, the catalyst
precursor has a surface area of at least 50 m.sup.2/g. In a third
embodiment, the catalyst precursor has a surface area of at least
150 m.sup.2/g.
[0102] In one embodiment, the catalyst precursor has an average
pore size, as defined by nitrogen adsorption, of 2-50 nanometers.
In a second embodiment, the catalyst precursor has an average pore
size, as defined by nitrogen adsorption, of 3-30 nanometers. In a
third embodiment, the catalyst precursor has an average pore size,
as defined by nitrogen adsorption, of 4-15 nanometers.
Shaping Process:
[0103] In one embodiment, the catalyst precursor composition can
generally be directly formed into various shapes depending on the
intended commercial use. These shapes can be made by any suitable
technique, such as by extrusion, pelletizing, beading, or spray
drying. If the amount of liquid of the bulk catalyst precursor
composition is so high that it cannot be directly subjected to a
shaping step, a solid-liquid separation can be performed before
shaping.
Addition of Pore forming Agents
[0104] The catalyst precursor can be mixed with a pore forming
agent including, but not limited to steric acid, polyethylene
glycol polymers, carbohydrate polymers, methacrylates, and
cellulose polymers. For example, the dried catalyst precursor can
be mixed with cellulose containing materials such as
methylcellulose, hydroxypropylcellulose, or other cellulose ethers
in a ratio of between 100:1 and 10:1 (wt. % catalyst precursor to
wt. % cellulose) and water added until a mixture of extrudable
consistency is obtained. Examples of commercially available
cellulose based pore forming agents include but are not limited to:
methocel (available from Dow Chemical Company), avicel (available
from FMC Biopolymer), and porocel (available from Porocel). The
extrudable mixture can be extruded and then optionally dried. In
one embodiment, the drying can be performed under an inert
atmosphere such as nitrogen, argon, or vacuum. In another
embodiment, the drying can be performed at elevated temperatures
between 70 and 200.degree. C. In yet another embodiment, the drying
is performed at 120.degree. C.
Optional Component--Diluent:
[0105] The term diluent may be used interchangeably with
binder.
[0106] In one embodiment, a diluent is optionally included in the
process for making the catalyst. Generally, the diluent material to
be added has less catalytic activity than the catalyst prepared
from the catalyst precursor composition (without the diluent) or no
catalytic activity at all. Consequently, by adding a diluent, the
activity of the catalyst can be reduced. Therefore, the amount of
diluent to be added in the process of the invention generally
depends on the desired activity of the final catalyst composition.
Diluent amounts from 0-95 wt. % of the total composition can be
suitable, depending on the envisaged catalytic application.
[0107] The diluent can be added to the Promoter metal(s), Promoter
metal containing mixtures, Group VIB metal(s) or metal containing
mixtures either simultaneously or one after the other.
Alternatively, the Promoter and Group VIB metal mixtures can be
combined together and subsequently a diluent can be added to the
combined metal mixtures. It is also possible to combine part of the
metal mixtures either simultaneously or one after the other, to
subsequently add the diluent and to finally add the rest of the
metal mixtures either simultaneously or one after the other.
Furthermore, it is also possible to combine the diluent with metal
mixtures in the solute state and to subsequently add a metal
compound at least partly in the solid state. The organic oxygen
containing ligand is present in at least one of the metal
containing mixtures.
[0108] In one embodiment, the diluent is composited with a Group
VIB metal and/or a Promoter metal, prior to being composited with
the bulk catalyst precursor composition and/or prior to being added
during the preparation thereof. Compositing the diluent with any of
these metals in one embodiment is carried out by impregnation of
the solid diluent with these materials.
[0109] Diluent materials include any materials that are
conventionally applied as a diluent or binder in hydroprocessing
catalyst precursors. Examples include silica, silica-alumina, such
as conventional silica-alumina, silica-coated alumina and
alumina-coated silica, alumina such as (pseudo)boehmite, or
gibbsite, titania, zirconia, cationic clays or anionic clays such
as saponite, bentonite, kaoline, sepiolite or hydrotalcite, or
mixtures thereof. In one embodiment, binder materials are selected
from silica, colloidal silica doped with aluminum, silica-alumina,
alumina, titanic, zirconia, or mixtures thereof.
[0110] These diluents can be applied as such or after peptization.
It is also possible to apply precursors of these diluents that,
during the process, are converted into any of the above-described
diluents. Suitable precursors are, e.g., alkali metal aluminates
(to obtain an alumina diluent), water glass (to obtain a silica
diluent), a mixture of alkali metal aluminates and water glass (to
obtain a silica alumina diluent), a mixture of sources of a di-,
tri-, and/or tetravalent metal such as a mixture of water-soluble
salts of magnesium, aluminum and/or silicon (to prepare a cationic
clay and/or anionic clay), chlorohydrol, aluminum sulfate, or
mixtures thereof.
Other Optional Components:
[0111] If desired, other materials, including other metals can be
added in addition to the components described above. These
materials include any material that is added during conventional
hydroprocessing catalyst precursor preparation. Suitable examples
are phosphorus compounds, borium compounds, additional transition
metals, rare earth metals, fillers, or mixtures thereof. Suitable
phosphorus compounds include ammonium phosphate, phosphoric acid,
or organic phosphorus compounds. Phosphorus compounds can be added
at any stage of the process steps. Suitable additional transition
metals that can be added to the process steps include are, e.g.,
rhenium, ruthenium, rhodium, iridium, chromium, vanadium, iron,
cobalt, platinum, palladium, and cobalt. In one embodiment, the
additional metals are applied in the form of water-insoluble
compounds. In another embodiment, the additional metals are added
in the form of water soluble compounds. Apart from adding these
metals during the process, it is also possible to composite the
final catalyst precursor composition therewith the optional
materials. It is, e.g., possible to impregnate the final catalyst
precursor composition with an impregnation solution comprising any
of these additional materials.
Sulfiding Agent Component:
[0112] The charge-neutral catalyst precursor of the general formula
A.sub.v[(M.sup.VIII)(OH).sub.x(L).sup.n.sub.y].sub.z(M.sup.VIBO.sub.4)
can be sulfided to form an active catalyst. In one embodiment, the
sulfiding agent is in the form of a solution, which, under
prevailing conditions, is decomposable into hydrogen sulphide. In
one embodiment, the sulfiding agent is present in an amount in
excess of the stoichiometric amount required to form the sulfided
catalyst from the catalyst precursor. In another embodiment, the
amount of sulfiding agent represents a sulphur to Group VIB metal
mole ratio of at least 3 to 1 to produce a sulfided catalyst from
the catalyst precursor.
[0113] In one embodiment, the sulfiding agent is selected from the
group of ammonium sulfide, ammonium polysulfide
([(NH.sub.4).sub.2S.sub.x), ammonium thiosulfate
((NH.sub.4).sub.2S.sub.2O.sub.3), thiosulfate
Na.sub.2S.sub.2O.sub.3), thiourea CSN.sub.2H.sub.4, carbon
disulfide, dimethyl disulfide (DMDS), dimethyl sulfide (DMS),
tertiarybutyl polysulfide (PSTB) and tertiarynonyl polysulfide
(PSTN), and the like. In another embodiment, the sulfiding agent is
selected from alkali- and/or alkaline earth metal sulfides, alkali-
and/or alkaline earth metal hydrogen sulfides, and mixtures
thereof. The use of sulfiding agents containing alkali- and/or
alkaline earth metals can require an additional separation process
step to remove the alkali- and/or alkaline earth metals from the
spent catalyst.
[0114] In one embodiment, the sulfiding agent is ammonium sulfide
in aqueous solution, which aqueous ammonium sulfide solution can be
synthesized from hydrogen sulfide and ammonia refinery off-gases.
This synthesized ammonium sulfide is readily soluble in water and
can easily be stored in aqueous solution in tanks prior to use.
Since the ammonium sulfide solution is denser than resid, it can be
separated easily in a settler tank after reaction.
[0115] The sulfiding agent can be elemental sulfur mixed with the
catalyst precursor during or prior to extrusion. The elemental
sulfur can be co-extruded with the catalyst precursor to form
active catalyst in situ during hydrotreatment.
[0116] In one embodiment, hydrocarbon feedstock is used as a sulfur
source for performing the sulfidation of the catalyst precursor.
Sulfidation of the catalyst precursor by a hydrocarbon feedstock
can be performed in one or more hydrotreating reactors during
hydrotreatment.
Sulfiding Step:
[0117] Sulfiding of the catalyst precursor to form the catalyst can
be performed prior to introduction of the catalyst into the
hydrotreating reactor, or in situ in the reactor. In one
embodiment, the catalyst precursor is converted into an active
catalyst upon contact with the sulfiding agent at a temperature
ranging from 70.degree. C. to 500.degree. C., from 10 minutes to 5
days, and under a H.sub.2-containing gas pressure. If the
sulfidation temperature is below the boiling point of the sulfiding
agent, such as 60-70.degree. C. in the case of ammonium sulfide
solution, the process is generally carried out at atmospheric
pressure. Above the boiling temperature of the sulfiding
agent/optional components, the reaction is generally carried out at
an increased pressure, such as in an autoclave.
[0118] In one embodiment, the sulfidation is carried out at a
temperature ranging from room temperature to 400.degree. C. and for
1/2 hr. to 24 hours. In another embodiment, the sulfidation is at
150.degree. C. to 300.degree. C. In yet another embodiment, the
sulfidation is between 300-400.degree. C. under pressure. In a
fourth embodiment, the sulfidation is with an aqueous ammonium
sulfide solution at a temperature between 0 and 50.degree. C., and
in the presence of at least a sulfur additive selected from the
group of thiodazoles, thio acids, thio amides, thiocyanates, thio
esters, thio phenols, thiosemicarbazides, thioureas, mercapto
alcohols, and mixtures thereof.
[0119] In one embodiment of the present invention, the catalyst of
the present invention optionally can include an additional
structural support material such as a refractory metal oxide
material such as for example silica, alumina, magnesia, titania,
etc. and mixtures thereof. The structural support can be in any
form including for example monolith, spheres, or hollow cylinders.
More specifically the metal oxide material can include "supports"
such as alumina, silica, silica-alumina, silicate,
alumino-silicate, magnesia, zeolite, active carbon, titanium oxide,
thorium oxide, clay and any combination of these supports. In one
embodiment of the present invention preferably, the invention's
catalyst can contain between 50% and 95% by weight of structural
support. In one embodiment of the present invention, the preferred
support was zirconia.
D. Process Conditions and Equipment
[0120] In one embodiment, the heavy hydrocarbon feedstream is
reacted with the catalyst in the presence of hydrogen in a fixed
bed reactor system. The fixed bed reactor system comprises at least
one reactor. Additionally, more than one reactor may be employed in
either series or parallel or both. Each reactor employed uses the
catalyst described herein. By optimizing the Group VIII and Group
VIB metal components and ratios, these catalysts used in the
process of this invention can be located in a single reactor to
convert LCO in one reactor directly to jet products.
[0121] The reaction zone comprises the catalyst in a fixed bed. The
heavy hydrocarbon feedstream is fed to the reaction zone, which has
a temperature of from about 300.degree. F. to about 900.degree. F.,
thereby producing a reaction product. In a preferred embodiment the
feedstream is LCO and the reaction products are jet fuel
products.
[0122] Typically, the contacting of the hydrocarbon feedstock takes
place in the reactor wherein the feedstock is contacted with the
catalyst. The reaction occurs at pressures ranging from 100 psig to
3000 psig, hydrocarbon feed LHSV (Liquid Hourly Space Velocity)
ranging from 0.1 to 10 hr.sup.-1, and a ratio of hydrogen to
hydrocarbon ranging from about 400-20,000 SCF/bbl. If a higher
conversion of the hydrocarbon feedstock is desirable, then the
process optionally includes a separation stage for recovering at
least a portion of the product which may contain unconverted
feedstock. At least a portion of the product stream is then,
optionally, recycled to the reactor system. In case the catalyst is
deactivated by coke deposit or other poisons, the catalyst activity
can be rejuvenated via regeneration. Processes which are suitable
for regeneration are known to those skilled in the art.
[0123] Treating the hydrocarbon feed at the above conditions can
substantially remove most of the sulfur and nitrogen compounds as
well as partially hydrogenate the aromatic compounds to give a
final aromatics content below 25% providing hydrocarbon products
that are low in sulfur and nitrogen and within jet fuel
specifications. More specifically, the inventive method can reduce
the amount of sulfur to less than about 15 wppm, more preferably
less than about 10 wppm and most preferably less than about 5 wppm.
It also can reduce the amount of nitrogen to less than about 10
wppm, more preferably to less than about 5 wppm and most preferably
less than about 1 wppm.
E. Product
[0124] The method employed in the present invention upgrades heavy
hydrocarbon feedstocks to jet fuel products. It has been discovered
that the present method employed produces jet fuel products that
have a net heat of combustion of greater than at least 125,000
Btu/gal, preferably the net heat of combustion is greater than at
least 127,000 Btu/gal, more preferably 128,500 Btu/gal, even more
preferably 129,500 Btu/gal. Furthermore, the product meets the
specifications for jet fuel. Specifically, the product has a
freezing point below -40.degree. C. for jet fuel. The product has a
smoke point greater than 18 mm. The product has a viscosity of less
than 8 cSt at -20 degrees Celsius. The product has a density of
less than 0.840 g/cc at -20 degrees Celsius.
[0125] Other embodiments will be obvious to those skilled in the
art.
EXAMPLES
[0126] The following examples are presented to illustrate specific
embodiments of this invention and are not to be construed in any
way as limiting the scope of the invention.
Example 1
Catalyst Precursor Formation
[0127] A catalyst precursor of the formula
(NH.sub.4).sup.+{[Ni.sub.2.6(OH).sub.2.08(C.sub.4H.sub.2O.sub.4.sup.2-).s-
ub.0.06](Mo.sub.0.35W.sub.0.65O.sub.4).sub.2} was prepared as
follows: 52.96 g of ammonium heptamolybdate
(NH.sub.4).sub.6Mo.sub.7O.sub.244H.sub.2O was dissolved in 2.4 L of
deionized (DI) water at room temperature. The pH of the resulting
solution was within the range of 5-6. 73.98 g of ammonium
metatungstate powder was then added to the above solution and
stirred at room temperature until completely dissolved. 90 ml of
concentrated (NH.sub.4)OH was added to the solution with constant
stirring. The resulting molybdate/tungstate solution was stirred
for 10 minutes and the pH monitored. The solution had a pH in the
range of 9-10. A second solution was prepared containing 174.65 g
of Ni(NO.sub.3).sub.26H.sub.2O dissolved in 150 ml of deionized
water and heated to 90.degree. C., thereby producing a hot nickel
solution which was then slowly added over 1 hr to the
molybdate/tungstate solution. The resulting mixture was heated to
91.degree. C. and stirred for another 30 minutes. The pH of the
solution was in the range of 5-6. A blue-green precipitate formed
and the precipitate was collected by filtration. The precipitate
was dispersed into a solution of 10.54 g of maleic acid dissolved
in 1.8 L of Di water and heated to 70.degree. C. The resulting
slurry was stirred for 30 min. at 70.degree. C., filtered to
produce a precipitate which was collected and vacuum dried at room
temperature overnight. The material was then further dried at
120.degree. C. for 12 hr. The resulting material has a typical XRD
pattern with a broad peak at 2.5 .ANG., denoting an amorphous
Ni--OH containing material. Surface area measurements were within
the range of 50-150 m.sup.2/g and an average pore volume within the
range of 0.1-0.2 cc/g with an average pore size of 5-50 nm as
measured by BET method.
Example 2
Sulfidation
[0128] 6.5 cc of the catalyst precursor of Example 1 was placed in
a tubular reactor and first purged with 700 cc/min N.sub.2 at
100.degree. F. overnight. Then the temperature was increased to
450.degree. F. in 4 hours. After having been held at 450.degree. F.
in this N.sub.2 flow for 1 hour, it was switched to 700 cc/min
H.sub.2 and the pressure was increased to 800 psig. It's held at
450.degree. F. and 800 psig in 700 cc/min H.sub.2 for 1 hour. Then
the sulfiding feed containing 6 wt. % DMDS (dimethyl disulfide) in
n-heptane was introduced at 36 cc/hr at 800 psig, 450.degree. F.
and 700 cc/min H.sub.2 and it was held for 2 hours under these
conditions. Subsequently the temperature was increased from
450.degree. F. to 650.degree. F. in 4 hours and it was held at
650.degree. F. for 2 hours. With the sulfiding feed still on, the
temperature was dropped from 650.degree. F. to .about.300.degree.
F. as soon as possible. Then the sulfiding feed was stopped, the
pressure was increased to the pre-selected reaction pressure such
as 1000 psig and the H.sub.2 rate was adjusted to 77.2 cc/min. At
this stage, the FCC LCO was started with a rate of 6.5 cc/hr at a
H.sub.2 rate of 77.2 cc/min, 1000 psig and .about.300.degree. F.
Subsequently the reactor temperature was increased from
.about.300.degree. F. to a pre-selected reaction temperature such
as 600.degree. F. at a rate of 1.degree. F./min. Then the reaction
proceeded at 6.5 cc/hr feed, 77.2 cc/min H.sub.2, 600.degree. F.
and 1000 psig.
Example 3
Catalysts
[0129] The following catalysts were used in the example of the
invention or in the comparative examples.
[0130] (1) The catalyst of the invention is hereinafter referred to
as Ni--Mo--W, which was prepared according to Examples 1 and 2.
[0131] (2) A hydrotreating catalyst comprising molybdenum and
nickel supported on an alumina base is hereinafter referred to as
Ni--Mo.
[0132] (3) A hydrofinishing catalyst comprising platinum and
palladium supported on a mixed silica-alumina/alumina base is
hereinafter referred to as Pt--Pd.
Example 4
Feedstock
[0133] Table 1 discloses the properties of the feedstock used in
the present invention. The feedstock is a light cycle oil (LCO)
product from the Fluid Catalytic Cracking unit in a refinery. The
feedstock was also analyzed with simulated distillation. The
results of the simulated distillation are listed in Table 2. This
feedstock has not been hydrotreated.
Example 5
Upgrade of LCO to Jet Fuels with Ni--Mo--W Catalyst of the Present
Invention as a Single Catalyst in a Single Fixed Bed Reactor
[0134] The FCC LCO feed, as described in Table 1 and Table 2 in
Example 4, was hydroprocessed in a single fixed bed reactor at a
feed rate of 6.5 cc/hr over 6.5 cc of the Ni--Mo--W catalyst of the
present invention, as described in Example 3. The reactor
temperature was 600.degree. F. and the reactor pressure was 1000
psig. Hydrogen feed rate was 77.2 cc/min.
[0135] The catalytic results are also listed in Table 1. The
results from the simulated distillation are also listed in Table 2.
The results indicate that the jet specifications are met.
Comparative Example 1
Upgrade of LCO to Jet Fuels with Ni--Mo Catalyst as a Single
Catalyst in One Single Fixed Bed Reactor
[0136] The FCC LCO feed, as described in Table 1 and Table 2 in
Example 4, was hydrotreated in a fixed bed reactor at a feed rate
of 11.2 cc/hr over 5.9 g of the Ni--Mo catalyst described in
Example 3 to compare with Ni--Mo--W catalyst of the invention
described in Example 5. In this comparative example, the
temperature was 660.degree. F. and the pressure was 1700 psig.
Hydrogen rate was 300 cc/min.
[0137] The catalytic results are also listed in Table 1. The
results from the simulated distillation are also listed in Table 2.
The results indicate that the jet product prepared with such a
Ni--Mo catalyst does not meet the jet specifications and
demonstrate the advance of Ni--Mo--W catalyst of the prevent
invention described in Example 5, especially due to its high
activity at a low pressure of 1000 psig and a low temperature of
600.degree. F.
Comparative Example 2
Upgrade of LCO to Jet Fuels with Ni--Mo Hydrotreating and Pt--Pd
Hydrofinishing catalysts in Two Fixed Bed Reactors
[0138] In Comparative Example 1, the FCC LCO feed described in
Table 1 and Table 2 in Example 4 was hydrotreated in a fixed bed
reactor at a feed rate of 11.2 cc/hr over 5.9 g of the Ni--Mo
catalyst described in Example 3. The resulting hydrotreating
product produced in this first reactor was then hydrofinished in a
second fixed bed reactor at a feed rate of 4 cc/hr over 4.7 g of
platinum/palladium hydrofinishing catalyst described in Example 3.
The temperature of this second reactor containing Pt/Pd catalyst
was 550.degree. F. and the pressure was 1000 psig. Hydrogen rate
was 100 cc/min. Thus, a jet product is produced via a two-stage
hydrotreating-hydrofinishing reactor system with each stage
containing one catalyst.
[0139] The properties of the jet product produced from this two
stage reactor system containing two catalysts are also listed in
Table 1. The reaction product was also analyzed with simulated
distillation. The results of the simulated distillation are also
listed in Table 2.
[0140] The results show the improvement of jet fuel properties
using such a two-stage hydroprocess which combines Ni--Mo and Pt/Pd
catalysts, as demonstrated, for example, by the improved smoke
point with still a high net heat of combustion of 128,781
Btu/gallon. By comparison to Example 5 which employs only a single
Ni--Mo--W catalyst in a single reactor, the process of Comparative
Example 2 is undesirable because a hydrotreating catalyst is used
in one reactor and a hydrofinishing catalyst is used in another
reactor to produce a high energy density jet fuel product. It may
be economically disadvantageous to use more than one catalyst and
more than one reactor to upgrade LCO to a high energy density jet
fuel product.
TABLE-US-00001 TABLE 1 Properties of FCC LCO Feedstock of Example 4
and Jet Fuels Produced in Example 5 as well as in Comparative
Examples 1 and 2 Jet Product Feed Produced over Produced over
Untreated Produced over Ni--Mo Ni--Mo and Pt--Pd FCC LCO Ni--Mo--W
Comparative Comparative Properties Jet Specs Example 4 Example 5
Example 1 Example 2 Density at 20.degree. C. g/cc 0.775-0.840 0.923
0.840 0.886 0.837 Smoke Point mm >18 5 24 8 25 Flash Point
.degree. C. >38 85 67 80 64 Freezing Point .degree. C. <-40
-22.1 -61.1 -58.7 -62.6 Viscosity at -20.degree. C. cSt <8 26.04
6.65 7.01 6.44 Net Heat of Combustion Btu/gal 137,034 129,965
132,700 128,781 Sulfur Content ppm wt. 2280 1.9 0.8 0.1 Nitrogen
Content ppm wt, 232 <0.1 <0.1 <0.1
TABLE-US-00002 TABLE 2 Simulated Distillation of FCC LCO Feedstock
of Example 4 and Jet Fuels Produced in Example 5 as well as in
Comparative Examples 1 and 2 Temperature .degree. F. Jet Product
Produced Produced Feed Produced over over Untreated over Ni--Mo
Ni--Mo and Pt--Pd FCC LCO Ni--Mo--W Comparative Comparative Vol. %
Example 4 Example 5 Example 1 Example 2 0.5 289 244 287 252 5 392
336 368 337 10 408 365 390 364 20 436 387 408 387 30 447 394 422
391 40 451 402 436 396 50 455 409 442 406 60 458 420 450 416 70 473
433 460 429 80 486 452 471 448 90 496 475 488 473 95 516 492 504
491 99 547 532 540 534 99.5 562 545 552 549
* * * * *