U.S. patent application number 16/706043 was filed with the patent office on 2021-06-10 for platinum encapsulated zeolite hydrocracking catalyst and methods of making same.
This patent application is currently assigned to Saudi Arabian Oil Company. The applicant listed for this patent is Saudi Arabian Oil Company. Invention is credited to Manal Al-Eid, Lianhui Ding.
Application Number | 20210170375 16/706043 |
Document ID | / |
Family ID | 1000005608790 |
Filed Date | 2021-06-10 |
United States Patent
Application |
20210170375 |
Kind Code |
A1 |
Ding; Lianhui ; et
al. |
June 10, 2021 |
PLATINUM ENCAPSULATED ZEOLITE HYDROCRACKING CATALYST AND METHODS OF
MAKING SAME
Abstract
Embodiments of the present disclosure are directed to
hydrocracking catalysts and methods of making same. The
hydrocracking catalyst comprises a platinum encapsulated zeolite
having a crystallinity greater than 20% determined by X-ray powder
diffraction analysis.
Inventors: |
Ding; Lianhui; (Dhahran,
SA) ; Al-Eid; Manal; (Dhahran, SA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Saudi Arabian Oil Company |
Dhahran |
|
SA |
|
|
Assignee: |
Saudi Arabian Oil Company
Dhahran
SA
|
Family ID: |
1000005608790 |
Appl. No.: |
16/706043 |
Filed: |
December 6, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01J 35/0006 20130101;
B01J 23/883 20130101; B01J 37/04 20130101; B01J 37/08 20130101;
B01J 29/70 20130101; C10G 11/05 20130101 |
International
Class: |
B01J 29/70 20060101
B01J029/70; B01J 23/883 20060101 B01J023/883; B01J 37/04 20060101
B01J037/04; B01J 37/08 20060101 B01J037/08; B01J 35/00 20060101
B01J035/00 |
Claims
1. A method of producing a hydrocracking catalyst, in which the
method comprises: adding sodium hydroxide, an aluminum compound, a
salt having an anion and a cation, and a silicon compound to an
aqueous solution to form an aqueous mixture; stirring the aqueous
mixture; adding a platinum compound to the aqueous mixture to form
a pre-catalyst mixture; heating the pre-catalyst mixture at from
80.degree. C. to 200.degree. C. for at least 24 hours, thereby
crystalizing the pre-catalyst mixture to form the hydrocracking
catalyst comprising platinum encapsulated zeolite; blending the
platinum encapsulated zeolite with zeolite Y, and optionally
alumina; and adding one or more metal-based catalysts selected from
nickel, molybdenum, tungsten, or combinations thereof to the
hydrocracking catalyst, in which the hydrocracking catalyst
comprises greater than 20% crystallinity determined by X ray powder
diffraction analysis.
2. The method of claim 1, wherein the zeolite is sodalite.
3. (canceled)
4. The method of claim 1, in which the aluminum compound comprises
aluminum metal powder, aluminum hydroxide, sodium aluminate, or
combinations thereof.
5. The method of claim 1, in which the silicon compound comprises
silica, sodium silicate, colloidal silica, fumed silica, or
combinations thereof.
6. The method of claim 1, in which the salt comprises sodium
chloride, potassium dichromate, calcium chloride, sodium bisulfate,
copper sulfate, or combinations thereof.
7. The method of claim 1, in which the platinum compound comprises
a platinum salt selected from the group of Pt(NH.sub.3)Cl.sub.2,
PtCl.sub.2, PtCl.sub.4, (NH.sub.4)2PtCl.sub.6,
(NH.sub.4)2Pt(NO.sub.3).sub.2, Na.sub.2PtCl.sub.6.6H.sub.2O,
H.sub.2PtCl.sub.6.6H.sub.2O, Na.sub.2PtCl.sub.4.4H.sub.2O,
(NH.sub.4)2PtCl.sub.4, or combinations thereof.
8. The method of claim 1, in which the pre-catalyst mixture
comprises xNaOH
:1Al.sub.2O.sub.3:2SiO.sub.2:yNaCl:z(NH.sub.4)2PtCl.sub.4:wH.sub.2O-
, where x=10-30, y=0-10, z=0.02-0.5, and w=100-500.
9. (canceled)
10. (canceled)
11. The method of claim 1, in which the adding involves mixing or
impregnation into zeolite Y, the platinum encapsulated zeolite, or
combinations thereof.
12. A hydrocracking catalyst comprising: platinum encapsulated
zeolite, the platinum encapsulated zeolite having a crystallinity
greater than 20% determined by X-ray powder diffraction analysis;
zeolite Y, optionally alumina; and nickel, molybdenum, tungsten, or
combinations thereof.
13. The hydrocracking catalyst of claim 12, in which the
hydrocracking catalyst comprises greater than 35%
crystallinity.
14. The hydrocracking catalyst of claim 12, wherein the zeolite
comprises sodalite.
15. The hydrocracking catalyst of claim 14, wherein the sodalite
comprises a pore size of 0.10 to 0.30 nanometers.
16-17. (canceled)
18. The hydrocracking catalyst of claim 12, in which the
hydrocracking catalyst comprises from 10 to 20 wt. % MoO.sub.3,
from 1 to 10 wt. % NiO, from 20 to 80 wt. % Al.sub.2O.sub.3, and
from 10 to 60 wt. % of platinum encapsulated sodalite and zeolite Y
combined.
19. The hydrocracking catalyst of claim 12, in which the
hydrocracking catalyst comprises from 20 to 30 wt. % WO.sub.3, from
1 to 10 wt. % NiO, from 20 to 80 wt. % Al.sub.2O.sub.3, and from 10
to 60 wt. % of platinum encapsulated sodalite and zeolite Y
combined.
20. The hydrocracking catalyst of claim 12, in which the
hydrocracking catalyst comprises from 1 to 10 wt. % sodalite and
platinum combined.
Description
BACKGROUND
Technical Field
[0001] The present disclosure generally relates to hydrocracking
technology and, more specifically, to platinum encapsulated zeolite
hydrocracking catalysts and methods of making these hydrocracking
catalysts.
Background
[0002] Compared with conventional steam cracking feedstocks, for
example, narrow fractions like natural gas, naphtha, and diesel,
the whole crude feedstocks include more impurities and a
considerable amount of polyaromatics, which cannot be directly
converted by steam cracking. To maximize the olefin and benzene,
toluene, and xylene (BTX) production from whole crude feedstock,
the whole crude feedstocks require hydroprocessing to remove the
impurities (S, N, and metals), convert polyaromatics, and convert
the heavy fraction to lighter fractions.
[0003] Hydrogenation of polyaromatics and hydrocracking of crude
oil are critical hydroprocessing steps to upgrade crude oil and
convert crude oil to clean fuel and petrochemicals.
Noble-metal-supported catalysts are often used in polyaromatics
hydrogenation and hydroconversion. However, the noble metal
catalysts are very susceptible to sulfur poisoning even at a few
parts per million (ppm) of H.sub.2S or sulfur compounds. Zeolite Y
is a widely used cracking component for use in heavy oil
hydrocracking catalysts. If a metal such as platinum (Pt) is
supported on Zeolite Y, which has large pore size (about 0.75 nm),
H.sub.2S can easily access and poison the Pt active sites. Sodalite
zeolite, which is often used as a noble metal support, has pore
sizes of 0.30 nm or less, which prevents the large molecules in the
crude oil from diffusing in and out of the zeolite pores; however,
larger molecules cannot be effectively hydrocracked, which greatly
reduces the reaction efficiency.
BRIEF SUMMARY
[0004] Thus, there is a need hydrocracking catalysts having
improved hydrocracking efficiency, while reducing sulfur poisoning
of catalyst.
[0005] Embodiments of the present disclosure meet this need for
improved hydrocracking catalysts. Specifically, the present
hydrocracking catalysts comprise platinum encapsulated in sodalite
zeolite cages (Pt/SOD). The pore openings of the sodalite zeolite
cages are sufficiently small to exclude the smallest
sulfur-containing molecules (H.sub.2S, 0.36 nm), while allowing
hydrogen molecules (0.28 nm) to diffuse into and out of the
sodalite cage and to react on Pt clusters to form efficiently
disassociated hydrogen atoms. These dissociated hydrogen atoms can
spill over to adjacent hydrogenation or acid sites, such as
alumina, zeolite Y, NiMo, and NiW metals, where the larger
hydrocarbon molecules can be hydrogenated and cracked. Therefore,
mixing the Pt encapsulated sodalite with a larger pore sized
Zeolite Y can greatly enhance hydrocracking of the crude oil.
[0006] In accordance with one embodiment of the present disclosure,
a method of making a hydrocracking catalyst is provided. The method
comprises: adding sodium hydroxide, an aluminum compound, a salt
having an anion and a cation, and a silicon compound to an aqueous
solution to form an aqueous mixture; stirring the aqueous mixture;
adding a platinum compound to the aqueous mixture to form a
pre-catalyst mixture; heating the pre-catalyst mixture at from
80.degree. C. to 200.degree. C. for at least 24 hours, thereby
crystalizing the pre-catalyst mixture to form the hydrocracking
catalyst comprising platinum encapsulated zeolite.
[0007] In accordance with another embodiment of the present
disclosure, a hydrocracking catalyst is provided. The hydrocracking
catalyst may comprise platinum encapsulated zeolite, the platinum
encapsulated zeolite having a crystallinity greater than 20%
determined by X-ray powder diffraction analysis.
BRIEF DESCRIPTION OF DRAWINGS
[0008] FIG. 1 is a schematic of the hydrocracking catalyst as well
as the hydrocracking reaction according to one or more embodiments
of the present disclosure.
[0009] FIG. 2 is a schematic of the hydrocracking catalyst as well
as the hydrocracking and the hydrogenation reactions according to
one or more embodiments of the present disclosure.
DETAILED DESCRIPTION
[0010] Embodiments of the present disclosure are directed to
hydrocracking catalysts and methods of making, and are specifically
directed to hydrocracking catalysts comprising Pt encapsulated
zeolite. Further embodiments are directed to hydrocracking
catalysts comprising these hydrocracking catalysts, additional
zeolites such as zeolite Y, as well as hydrogenation catalysts
(e.g., NiMo or NiW).
[0011] As used throughout this disclosure, "whole crude", "crude
oil", or "whole crude feedstock" refers to unrefined petroleum
crude oil, as well as crude oil that has undergone some
pre-treatment before hydrocracking. As used in this disclosure,
"pretreatment" encompasses water-oil separation, gas-oil
separation, desalting, stabilization, or combinations of such;
however, it does not encompass crude oil, which undergoes
distillation (e.g., vacuum distillation or atmospheric
distillation) prior to hydrocracking. The crude oil may have an
American Petroleum Institute (API) Gravity (.degree.) of 10.degree.
to 50.degree..
[0012] As used throughout this disclosure, the term "hydrocracking"
involves the catalytic cracking of heavy hydrocarbon molecules in
the crude oil into smaller olefins and aromatics, the cracking
being performed in the presence of at least one catalyst and
hydrogen. "Hydrocracking" also encompasses hydrogenation, which
involves adding hydrogen to unsaturated hydrocarbons, such as
olefins and aromatics, for stabilization of petroleum products and
aromatic reduction. Specifically, the hydrogenation converts
olefins and aromatics into paraffins and naphthenes. Moreover,
"hydroprocessing" encompasses hydrocracking and additional reaction
mechanisms, for example, hydrodearomatization,
hydrodenitrogenation, hydrodesulfurization, or combinations of
such.
[0013] Embodiments for making the hydrocracking catalysts are
provided below. According to one embodiment, the hydrocracking
catalyst is produced by adding sodium hydroxide, an aluminum
compound, a salt having an anion and a cation, and a silicon
compound to an aqueous solution to form an aqueous mixture;
stirring the aqueous mixture; adding a platinum compound to the
aqueous mixture to form a pre-catalyst mixture; heating the
pre-catalyst mixture at from 80.degree. C. to 200.degree. C. for at
least 24 hours, thereby crystalizing the pre-catalyst mixture to
form the hydrocracking catalyst comprising platinum encapsulated
zeolite. As will be described in further detail in subsequent
paragraphs, the platinum encapsulated zeolite may comprise
sodalite.
[0014] Various compounds are considered suitable for the aluminum
compound, for example, aluminum metal powder, aluminum hydroxide
(Al(OH).sub.3), sodium aluminate (NaAlO.sub.2), or combinations
thereof. In one embodiment, the aluminum compound comprises
aluminum hydroxide.
[0015] In one or more embodiments, the silicon compound may
comprise silica, sodium silicate, colloidal silica, fumed silica,
or combinations thereof. In one embodiment, the silicon compound
comprises colloidal silica.
[0016] The salt may comprise sodium chloride, potassium dichromate,
calcium chloride, sodium bisulfate, copper sulfate, or combinations
thereof. In one embodiment, the salt comprises sodium chloride.
[0017] Furthermore, various compounds are considered suitable for
the platinum compound, such as a platinum salt. The platinum salt
may comprise Pt(NH.sub.3)Cl.sub.2, PtCl.sub.2, PtCl.sub.4,
(NH.sub.4)2PtCl.sub.6, (NH.sub.4)2Pt(NO.sub.3).sub.2,
Na.sub.2PtCl.sub.6.6H.sub.2O, H.sub.2PtCl.sub.6.6H.sub.2O,
Na.sub.2PtCl.sub.4.4H.sub.2O, (NH.sub.4)2PtCl.sub.4, or
combinations thereof. In one embodiment, the platinum compound
comprises (NH.sub.4)2PtCl.sub.4.
[0018] Based on the varied component possibilities described above,
it is contemplated that the pre-catalyst mixture or pre-catalyst
slurry may encompass many different component mixtures. In one of
more embodiments, the pre-catalyst mixture comprises
xNaOH:1Al.sub.2O.sub.3:2SiO.sub.2:yNaCl:z(NH.sub.4)2PtCl.sub.4:wH.sub.2O,
where x=10-30, y=0-10, z=0.02-0.5, and w=100-500.
[0019] Various processing conditions may be utilized to produce the
platinum encapsulated zeolite. For example, the pre-catalyst
mixture may be heated for at least 12 hours, at least 24 hours, at
least 48 hours, or at least 72 hours. Moreover, additional steps
such as flushing are contemplated after the formation of the
platinum encapsulated zeolite. For example, the platinum
encapsulated zeolite may be flushed by: adding a second aqueous
solution (e.g., deionized water) to the platinum encapsulated
zeolite; stirring the platinum encapsulated zeolite within the
second aqueous solution (e.g., deionized water); and centrifuging
the platinum encapsulated zeolite within the second aqueous
solution to separate the platinum encapsulated zeolite from the
second aqueous solution. This flushing step may be conducted
repeatedly until the second aqueous solution comprises less than 1
ppm of the anion after separating the platinum encapsulated zeolite
from the second aqueous solution.
[0020] Moreover, the process may include comprising drying the
platinum encapsulated zeolite for at least 2 hours, or at least 4
hours, or at least 8 hours. In addition to drying duration, various
drying temperatures are suitable. For example, the drying
temperature may be from 90 to 150.degree. C., or from 100.degree.
C. to 120.degree. C.
[0021] In further embodiments, the platinum encapsulated zeolite
may be blended with other components, such as zeolites, alumina and
additional metal-based catalysts. In one embodiment, the platinum
encapsulated sodalite zeolite is blended with zeolite Y. In a
specific embodiment, zeolite Y comprises ultra stable zeolite
(USY). Moreover, metal-based catalysts such as nickel, molybdenum,
tungsten, or combinations thereof may be blended with the zeolite Y
and the platinum encapsulated zeolite. The addition of these
metal-based catalysts may include mixing or impregnation into
zeolite Y, the platinum encapsulated zeolite, or combinations
thereof. As would be familiar to the skilled person, the zeolite Y,
alumina, platinum encapsulated zeolite, and the metal-based
catalyst (e.g., Ni) may be blended in combination with a
binder.
[0022] For illustration and not by way of limitation, an exemplary
embodiment of producing a hydrocracking catalyst is provided. As an
initial step, a hydrothermal synthesis method is utilized for
producing the Pt-encapsulated sodalite. The gel composition is
xNaOH:1Al.sub.2O.sub.3:2SiO.sub.2:yNaCl:zPt salt: wH.sub.2O where
x=10-30, y=0-10, z=0.02-0.5, and w=100-500. A typical synthesis
method is listed as follows:
[0023] (1) NaOH is dissolved in deionized H.sub.2O.
[0024] (2) Al(OH)3 is added and gently heated under stirring into
the solution obtained from step (1) until the Al is completely
dissolved to form clear solution. The water loss during heating is
made up during this step.
[0025] (3) Colloidal SiO.sub.2 and NaCl are added into the clear
solution from (2), vigorously stirred for 30-60 minutes to form a
slurry.
[0026] (4) Add (NH.sub.4)2PtCl.sub.4 (or PtCl.sub.2 or
Na.sub.2PtCl.sub.6), stirred until completely dissolved.
[0027] The slurry from (4) is transferred into a polypropylene
bottle, sealed, and then put into an oven at 80-200.degree. C. for
24-72 hours.
[0028] After crystallization, the solid product is transferred into
a polypropylene beaker, added water, stirred at 60.degree. C. for
30 min, and then Centrifuged for separation of the solid product.
This may be repeated until no Cl-- is detected in solution (test
with 0.1M AgNO.sub.3 solution).
[0029] The solid product is then dried at 100-120.degree. C.
overnight. With the aforementioned zeolite Y and Pt-sodalite, the
hydrocracking catalysts are prepared either by mixing or
impregnation method.
[0030] In addition to methods of making, additional embodiments are
directed to the hydrocracking catalysts produced therefrom. As
stated previously, the hydrocracking catalysts may comprise a
platinum encapsulated zeolite having a crystallinity greater than
20% determined by X ray powder diffraction analysis.
[0031] In one or embodiments, the zeolite may be a sodalite
(Na.sub.8(Al.sub.6Si.sub.6O.sub.24)Cl.sub.2) zeolite, which
contains a cubic crystal structure. In one embodiment, the sodalite
has a Si/Al molar ratio is 0.8 to 1.2, or 1. Sodalite has a
six-membered oxygen aperture with a narrow pore diameter. Only very
small molecules such as hydrogen (2.8 .ANG.), helium (2.6 .ANG.),
ammonia (2.5 .ANG.), and water (2.65 .ANG.) can access and enter
the voids making sodalite a suitable candidate in separation of
these smaller molecules. This cubic crystal structure of the
sodalite, which is also called a sodalite cage, encapsulates the
platinum. Referring to FIGS. 1 and 2, the pore size of the sodalite
cage may range between the kinetic diameters of H.sub.2 and
H.sub.2S. Therefore, the H.sub.2S is excluded from entering the
sodalite cage, while hydrogen molecules can enter into the sodalite
cage to be adsorbed and react on the Pt cluster encapsulated by the
sodalite. As a result, the hydrogen can be easily and efficiently
disassociated to H atoms, which is highly active for polyaromatic
hydrogenation and cracking of larger molecules. Due to pore size of
the sodalite, the Pt inside the sodalite cannot be poisoned by the
H.sub.2S and other sulfur compounds.
[0032] As stated previously, the pore size of the sodalite needs to
be sufficient to exclude the smallest sulfur-containing molecules,
while allowing hydrogen molecules to diffuse into and out of the
sodalite cages. In one or more embodiments, the pore size of the
sodalite may be from 0.10 nm to 0.30 nm, from 0.15 nm to 0.30 nm,
from 0.25 nm to 0.30 nm, or 0.30 nm when calculated using the
Brunauer-Emmett-Teller (BET) technique. The surface area of the
sodalite may be from 0.05 to 0.20 m.sup.2/g, from 0.05 to 0.20
m.sup.2/g, from 0.10 to 0.15 m.sup.2/g, or 0.12 m.sup.2/g. The pore
volume of the sodalite may be from 0.05 to 0.20 ml/g, from 0.05 to
0.20 ml/g, from 0.10 to 0.15 ml/g, or 0.13 ml/g.
[0033] In further embodiments, the platinum encapsulated zeolite
(e.g., Pt-sodalite) comprises greater than 35% crystallinity, or
greater than 50% crystallinity, or greater than 75% crystallinity,
or greater than 95% crystallinity. In further embodiment, the
hydrocracking catalyst may comprise a crystallinity of 25 to 50%,
from 30 to 45%, or from 30 to 40% as measured according to X-ray
powder diffraction analysis.
[0034] As described previously and shown in FIGS. 1 and 2, the
platinum encapsulated sodalite can dissociate H atoms, which spill
over to adjacent hydrogenation sites or acid sites to assist in
cracking and hydrogenation. As a result, further embodiments of the
hydrocracking catalysts may include additional zeolites such as
zeolite Y. Further embodiments may also include alumina. In one
embodiment, the zeolite Y comprises ultra stable zeolite Y (USY).
When the platinum encapsulated sodalite is blended with the zeolite
Y, it is contemplated that the sodalite cage is adjacent the
zeolite Y framework or disposed within the zeolite Y framework.
[0035] The zeolite Y may be defined by various properties. For
example, the zeolite Y may have a SiO.sub.2/Al.sub.2O.sub.3 Mole
Ratio may be from 5 to 80, from 10 to 60, from 20 to 60, or from
30-50. Additionally, the zeolite Y may have a surface area greater
than 700 m.sup.2/g. In another embodiment, the zeolite Y may have a
surface area from 700 to 750 m.sup.2/g. As mentioned previously,
the zeolite Y will have bigger pore sizes than the sodalite cage,
for example, about from 0.70 to 0.80 nm, or from 0.74 to 0.76
nm.
[0036] Moreover, the hydrocracking catalyst may include
hydrogenation catalysts, which typically comprise metal-based
materials. These metal-based materials may include metal elements,
metal oxides, metal hydroxides, alloys, and combinations thereof.
In one or more embodiments, these metal-based materials may
comprise comprises nickel, molybdenum, tungsten, or combinations
thereof. Structurally, the metal-based materials may be impregnated
within the zeolite Y, the platinum encapsulated zeolite, the
alumina, or combinations thereof. Moreover, metal-based materials
may be disposed on the surfaces of the zeolite Y, the platinum
encapsulated zeolite, the alumina, or combinations thereof. In
operation, large hydrocarbon molecules can be hydrogenated and
cracked by the hydrogenation catalysts in combination with the
dissociated ions produced from the hydrocracking performed by the
Pt encapsulated sodalite. While the present discussion categorized
catalysts like nickel supported zeolite Y as hydrogenation
catalysts, concurring reactions like hydrocracking are also
contemplated and expected.
[0037] In one embodiment, the hydrocracking catalyst may comprise a
NiMo catalyst. In one or embodiments, the hydrocracking catalyst
may comprise 5 wt. % to 50 wt. %, 10 wt. % to 40 wt. %, or 10 to 20
wt. % NiMo catalyst. The NiMo catalyst may comprise a combination
of metal-based materials, for example, MoO.sub.3 and NiO. In one or
more embodiments, the hydrocracking catalyst may comprise 10 to 20
wt. %, or 14 to 16 wt. % MoO.sub.3, and additionally 1 to 10 wt. %,
or 4 to 6 wt. % NiO.
[0038] In another embodiment, the hydrocracking catalyst may
comprise a NiW catalyst. In one or embodiments, the hydrocracking
catalyst may comprise 5 wt. % to 50 wt. %, 10 wt. % to 40 wt. %, or
20 to 30 wt. % NiW catalyst. The NiW catalyst may comprise a
combination of metal-based materials, for example, WO.sub.3 and
NiO. In one or more embodiments, the hydrocracking catalyst may
comprise 20 to 30 wt. %, or 20 to 26 wt. % WO.sub.3, and
additionally 1 to 10 wt. %, or 4 to 6 wt. % NiO.
[0039] Moreover, the hydrocracking catalyst may comprise 10 to 80
wt. % of platinum encapsulated sodalite and zeolite Y, or from 10
to 60 wt. % of platinum encapsulated sodalite and zeolite Y, or
from 20 to 60 wt. % of platinum encapsulated sodalite and zeolite
Y, or from 30 to 60 wt. % of platinum encapsulated sodalite and
zeolite Y, or from 40 to 60 wt. % of platinum encapsulated sodalite
and zeolite Y. The hydrocracking catalyst may comprise 1 to 30 wt.
% platinum encapsulated sodalite, or from 1 to 20 wt. % platinum
encapsulated sodalite, or from 1 to 10 wt. % platinum encapsulated
sodalite. Moreover, the hydrocracking catalyst may comprise 10 to
60 wt. % zeolite Y, or from 20 to 50 wt. % zeolite Y, or from 30 to
50 wt. % zeolite Y.
[0040] In one or more embodiments, the hydrocracking catalyst
comprises less than 20 wt. % platinum, or less than 15 wt. %
platinum, or less than less than 5 wt. % platinum based on the
overall weight of the hydrocracking catalyst.
[0041] Optionally, the hydrocracking catalyst may comprise alumina
(Al.sub.2O.sub.3) mixed with the other components. Various amounts
are contemplated, for example, 10 to 80 wt. %, 20 to 80 wt. %, 10
to 70 wt. %, 10 to 50 wt. %, 20 to 40 wt. %, or from 25 to 35 wt. %
Al.sub.2O.sub.3. The alumina may be defined by various properties;
however, the alumina will have a larger pore size than the
sodalite. For example, the alumina may have a pore size greater
than 10 nm, and a surface area great than 150 m.sup.2/g.
[0042] In another embodiment, the NiMo catalyst may comprise from
10 to 20 wt. % MoO.sub.3, from 1 to 10 wt. % NiO, from 20 to 80 wt.
% Al.sub.2O.sub.3, and from 10 to 60 wt. % of platinum encapsulated
sodalite and zeolite Y. In yet another embodiment, the NiW
hydrocracking catalyst comprises from 20 to 30 wt. % WO.sub.3, from
1 to 10 wt. % NiO, from 20 to 80 wt. % Al.sub.2O.sub.3, and from 10
to 60 wt. % of platinum encapsulated sodalite and zeolite Y.
[0043] Testing Methods
[0044] BET Technique
[0045] The sample texture properties, including surface areas, pore
volumes, pore sizes, and pore size distributions, were
characterized by physisorption using the BET technique on data
acquired from a Quantachrome Autosorb iQ instrument. Before
adsorption, the samples were calcined at 873K for 4 hrs.
Approximately 30-40 mg of powder samples were degassed in a sample
preparation station under 473K and 1.33E-3 Pa for 15 hours, then
switched to the analysis station for adsorption and desorption
under liquid nitrogen at 77K with an equilibrium time of 2 minutes.
The surface area was calculated with the multipoint BET equation
with linear region in the P/Po range of 0.05 to 0.35. Pore volume
was calculated from the maximum adsorption amount of nitrogen at
P/Po=0.99.
[0046] XRD Powder Diffraction Analysis
[0047] The crystallinity and phase purity of the solid products was
measured by powder X-ray diffraction (XRD) using a Rigaku Ultima IV
multi-purpose diffractometer with a copper X-ray tube. The scanning
range was set between 2.degree. to 50.degree. in 2.theta.
Bragg-angles with a step size of 0.04.degree. and the total
counting time of 1.degree. per minute. The crystallinity percentage
was calculated by PANalytical High Score Plus software through the
comparison of the area under the most intense diffraction peaks to
that of patterns of the reference zeolite (sodalite without
encapsulated Pt). The crystallinity of the reference (comparative)
zeolite is 100%.
EXAMPLES
[0048] With PtCl.sub.2 and (NH.sub.4)2PtCl.sub.4 as Pt source, the
hydrothermal synthesis of Pt-sodalite was conducted, the gel
composition and synthesis conditions are summarized in Table 1. The
results show that, under all conditions, the Pt-sodalite can be
formed. With the Pt content increase, the relative crystallinity
dramatically decreased.
TABLE-US-00001 TABLE 1 Pt/Sodalite hydrothermal synthesis using
different Pt sources and amounts Sample name SZ-5 SZ-6 SZ-7 Gel
molar ratio PtCl.sub.2 1.0 NaOH 20 20 15 Al.sub.2O.sub.3 1 1 1
SiO.sub.2 1 1 1 (NH.sub.4).sub.2PtCl.sub.4 2 0.05 0 H.sub.2O 300
300 300 Hydrothermal conditions Temperature 140 140 140 Time, hour
72 168 48 Dried solid yeild, g 4.58 3.13 0.53 XRD results Sodalite
Sodalite Sodalite Crystallinity, % 20 100 38 Pt. wt. % 59 2.8
14.54
[0049] Referring to Table 2 below, with SZ-6 Pt/sodalite, a
hydrocracking catalyst was synthesized. Meanwhile, a reference
catalyst without SZ-6 zeolite was synthesized under the same
composition and synthesis procedures. The hydrothermally
synthesized SZ-6 and/or USY zeolite (CBV-760 from Zeolyst) were
mixed with large-pore alumina (Sasol PURALOX TH100/150, pore volume
0.96 mL/g, specific surface area 201.6 m.sup.2/g), MoO.sub.3,
nickel nitrate hexahydrate, and binder (partially acid-peptized
alumina, SASOL, CATAPAL B), extruded to form cylindrically shaped
extrudate, dried at 383 K overnight, and then calcined in air at
773 K for 4 h. The composition of the inventive catalyst and
comparative catalyst are summarized in Table 2.
TABLE-US-00002 TABLE 2 The compositions of the catalysts with and
without Pt/sodalite. No. MoNi/Pt-sodalite-USY MoNi/USY Composition,
wt. % MoO.sub.3 15 15 NiO 5 5 USY 40 50 Pt/sodalite (SZ-6) 10
Al.sub.2O.sub.3 30 30
[0050] Catalyst performance tests were carried out in a 5 ml
fix-bed microreactor (Autoclave Engineer, BTR-Jr-PC) in a
continuous operating mode. The 3 ml 20-40 mesh catalyst was diluted
with 100 mesh sand of the same volume. Before each run, the
catalysts were pre-sulfided in situ in a 20 vol % H.sub.2S/H.sub.2
stream at 320.degree. C. for 2 h and 360.degree. C. for another 2 h
under a hydrogen pressure of 220 psi, LHSV 2.0 h-1, and hydrogen
flow rate 200 ml/min. 1-methylnaphthlene (MN) (20 wt. % in
hexadecane) was used as the model compound. The model compound were
fed into the system with a HPLC pump. The liquid product were
analyzed by a GC-MS (SHIMADZU GCMS-QP5000). The evaluation
conditions: reaction temperature 350.degree. C., H.sub.2 pressure
220 psig, LHSV 2.0h-1, and H.sub.2/MN volume ratio 1000:1. In order
to test the sulfur resistance of Pt/sodalite, a certain amount of
DMDS (equivalent to 20 ppm H.sub.2S) was added to the reactor along
with the 1-MN for some tests. The evaluation results are listed in
Table 3. Compared with the MoNi/USY catalyst, the addition of the
Pt encapsulated sodalite, the 1-MN hydrogenation and conversion
increased about 24 wt. %. Pt is located inside the sodalite, and
cannot be poisoned by H.sub.2S. thus, when 20 ppm of H.sub.2S was
introduced, the 1-MN conversion is only slightly deceased.
TABLE-US-00003 TABLE 3 The reaction performance of the invented and
reference catalysts Inventive MoNi/ Comparative Catalyst
Pt-sodalite-USY MoNi/USY H.sub.2S, ppm 20 1-MN conversion, wt. %
85.2 80.1 61.4 Product distribution, wt. % Methyl-butyl benzene
21.6 19.9 10.7 Pentybenzene 22.8 21 11.9 Methyl
tetrahydronaphthlene 40.9 39.2 39 1-MN 14.8 19.9 38.6
[0051] It should be understood that the various aspects of the
hydrocracking catalysts and the methods of making these
hydrocracking catalysts may be utilized in conjunction with various
other aspects.
[0052] According to a first aspect, a method of producing a
hydrocracking catalyst is provided, in which the method comprises:
adding sodium hydroxide, an aluminum compound, a salt having an
anion and a cation, and a silicon compound to an aqueous solution
to form an aqueous mixture; stirring the aqueous mixture; adding a
platinum compound to the aqueous mixture to form a pre-catalyst
mixture; and heating the pre-catalyst mixture at from 80.degree. C.
to 200.degree. C. for at least 24 hours, thereby crystalizing the
pre-catalyst mixture to form the hydrocracking catalyst comprising
platinum encapsulated zeolite.
[0053] According to a second aspect, which includes the first
aspect, the zeolite is sodalite.
[0054] According to a third aspect, which includes any of the first
or second aspects, the hydrocracking catalyst comprises greater
than 20% crystallinity determined by X ray powder diffraction
analysis.
[0055] According to a fourth aspect, which includes any of the
first through third aspects, the aluminum compound comprises
aluminum metal powder, aluminum hydroxide, sodium aluminate, or
combinations thereof.
[0056] According to a fifth aspect, which includes any of the first
through fourth aspects, the silicon compound comprises silica,
sodium silicate, colloidal silica, fumed silica, or combinations
thereof.
[0057] According to a sixth aspect, which includes any of the first
through fifth aspects, the salt comprises sodium chloride,
potassium dichromate, calcium chloride, sodium bisulfate, copper
sulfate, or combinations thereof.
[0058] According to a seventh aspect, which includes any of the
first through sixth aspects, the platinum compound comprises a
platinum salt selected from the group of Pt(NH.sub.3)Cl.sub.2,
PtCl.sub.2, PtCl.sub.4, (NH.sub.4)2PtCl.sub.6,
(NH.sub.4)2Pt(NO.sub.3).sub.2, Na.sub.2PtCl.sub.6.6H.sub.2O,
H.sub.2PtCl.sub.6.6H.sub.2O, Na.sub.2PtCl.sub.4.4H.sub.2O,
(NH.sub.4)2PtCl.sub.4, or combinations thereof.
[0059] According to an eighth aspect, which includes any of the
first through seventh aspects, the pre-catalyst mixture comprises
xNaOH:1Al.sub.2O.sub.3:2SiO.sub.2:yNaCl:z(NH.sub.4)2PtCl.sub.4:wH.sub.2O,
where x=10-30, y=0-10, z=0.02-0.5, and w=100-500.
[0060] According to a ninth aspect, which includes any of the first
through eighth aspects, the method further comprises blending the
platinum encapsulated zeolite with zeolite Y.
[0061] According to a tenth aspect, which includes any of the first
through ninth aspects, the method may further comprises adding one
or more metal-based catalysts selected from nickel, molybdenum,
tungsten, or combinations thereof to the hydrocracking
catalyst.
[0062] According to an eleventh aspect, which includes any of the
first through tenth aspects, the method of adding may involve
mixing or impregnation into zeolite Y, the platinum encapsulated
zeolite, or combinations thereof.
[0063] According to a twelfth aspect, a hydrocracking catalyst
comprises platinum encapsulated zeolite, the platinum encapsulated
zeolite having a crystallinity greater than 20% determined by X-ray
powder diffraction analysis.
[0064] According to a thirteenth aspect, which includes the twelfth
aspect, the hydrocracking catalyst comprises greater than 35%
crystallinity.
[0065] According to a fourteenth aspect, which includes any of the
twelfth through thirteenth aspects, the zeolite comprises
sodalite.
[0066] According to a fifteenth aspect, which includes any of the
twelfth through fourteenth aspects, the sodalite comprises a pore
size of 1.0 to 3.0 nanometers.
[0067] According to a sixteenth aspect, which includes any of the
twelfth through fifteenth aspects, the hydrocracking catalyst
further comprises zeolite Y, and optionally alumina.
[0068] According to a seventeenth aspect, which includes any of the
twelfth through sixteenth aspects, the hydrocracking catalyst
further comprises nickel, molybdenum, tungsten, or combinations
thereof.
[0069] According to an eighteenth aspect, which includes any of the
twelfth through seventeenth aspects, the hydrocracking catalyst
comprises from 10 to 20 wt. % MoO.sub.3, from 1 to 10 wt. % NiO,
from 20 to 80 wt. % Al.sub.2O.sub.3, and from 10 to 60 wt. % of
platinum encapsulated sodalite and zeolite Y.
[0070] According to a nineteenth aspect, which includes any of the
twelfth through seventeenth aspects, the hydrocracking catalyst
comprises from 20 to 30 wt. % WO.sub.3, from 1 to 10 wt. % NiO,
from 20 to 80 wt. % Al.sub.2O.sub.3, and from 10 to 60 wt. % of
platinum encapsulated sodalite and zeolite Y.
[0071] According to a twentieth aspect, which includes any of the
twelfth through nineteenth aspects, the hydrocracking catalyst
comprises from 1 to 10 wt. % sodalite and platinum combined.
[0072] Having described the subject matter of the present
disclosure in detail and by reference to specific embodiments, it
is noted that the various details disclosed in the present
disclosure should not be taken to imply that these details relate
to elements that are essential components of the various
embodiments described in the present disclosure. Further, it will
be apparent that modifications and variations are possible without
departing from the scope of the present disclosure, including, but
not limited to, embodiments defined in the appended claims.
* * * * *