U.S. patent application number 10/678693 was filed with the patent office on 2004-06-10 for integrated process for catalytic dewaxing.
Invention is credited to Angelo, Jacob B., Cody, Ian A., Jiang, Zhaozhong, Murphy, William J., Trewella, Jeffrey C..
Application Number | 20040108250 10/678693 |
Document ID | / |
Family ID | 32096169 |
Filed Date | 2004-06-10 |
United States Patent
Application |
20040108250 |
Kind Code |
A1 |
Murphy, William J. ; et
al. |
June 10, 2004 |
Integrated process for catalytic dewaxing
Abstract
An integrated process is disclosed for dewaxing hydrocarbon
feedstocks in a sour environment. The process includes
hydrotreating, dewaxing, hydrofinishing or combination thereof
wherein there is no disengagement between any of the process
steps.
Inventors: |
Murphy, William J.; (Baton
Rouge, LA) ; Cody, Ian A.; (Baton Rouge, LA) ;
Angelo, Jacob B.; (Spring, TX) ; Jiang,
Zhaozhong; (Somerville, NJ) ; Trewella, Jeffrey
C.; (Kennett Square, PA) |
Correspondence
Address: |
EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
P.O. BOX 900
1545 ROUTE 22 EAST
ANNANDALE
NJ
08801-0900
US
|
Family ID: |
32096169 |
Appl. No.: |
10/678693 |
Filed: |
October 3, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60416866 |
Oct 8, 2002 |
|
|
|
60490155 |
Jul 25, 2003 |
|
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Current U.S.
Class: |
208/89 ; 208/27;
208/87 |
Current CPC
Class: |
C10G 67/04 20130101;
C10G 65/043 20130101; C10G 45/64 20130101 |
Class at
Publication: |
208/089 ;
208/027; 208/087 |
International
Class: |
C10G 073/38; C10G
069/00 |
Claims
1. An integrated process for dewaxing a raffinate feedstock
containing up to 20,000 ppmw sulfur and up to 1000 ppmw nitrogen
which comprises: (a) contacting the feedstock with a hydrotreating
catalyst under hydrotreating conditions to produce a hydrotreated
feedstock and gaseous nitrogen- and sulfur-containing contaminants,
and (b) passing at least a portion of the hydrotreated feedstock
and gaseous components from step (a) without disengagement to a
hydrodewaxing zone containing a dewaxing catalyst including at
least one of ZSM-48, ZSM-22, ZSM-23, ZSM-5, ZSM-35, Beta,
SSZ-31,SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42, synthetic
ferrierites, mordenite, offretite, erionite, and chabazite and
hydrodewaxing the hydrotreated feedstock under hydrodewaxing
conditions, said dewaxing catalyst including a metal hydrogenation
component which is at least one Group 6 metal, at least one Group
8-10 metal, or mixtures of Group 6 and Group 8-10 metals, to form a
hydrodewaxed product.
2. The process of claim 1 wherein the hydrotreating conditions
temperatures of 315-425.degree. C., pressures of 2170-20786 kPa,
Liquid Hourly Space Velocities (LHSV) of 0.1-10 and hydrogen treat
rates of 89-1780 m.sup.3/m.sup.3.
3. The process of claim 1 wherein the metal hydrogenation component
is Pt, Pd or mixtures thereof.
4. The process of claim 1 wherein the hydrodewaxing conditions
include a temperature of 360 to 425.degree. C., hydrogen pressures
of from 2859-20786 kPa, liquid hourly space velocities of 0.1 to 10
LHSV and hydrogen treat gas rates of from 53.4-1780
m.sup.3/m.sup.3.
5. The process of claim 1 further comprising a hydrofinishing step
following step (b).
6. The process of claim 1 wherein the dewaxing catalyst contains
ZSM-48.
7. The process of claim 1 wherein the dewaxing catalyst further
comprises a second dewaxing catalyst.
8. An integrated process for dewaxing a raffinate feedstock
containing up to 20,000 ppmw sulfur and up to 1000 ppmw nitrogen
which comprises: (a) contacting the feedstock with a hydrotreating
catalyst under hydrotreating conditions to produce a hydrotreated
feedstock and gaseous nitrogen- and sulfur-containing contaminants,
(b) passing at least a portion of the hydrotreated feedstock and
gaseous sulfur- and nitrogen-containing contaminants from step (a)
without disengagement to a hydrodewaxing zone containing a dewaxing
catalyst including at least one of ZSM-48, ZSM-22, ZSM-23, ZSM-5,
ZSM-35, Beta, SSZ-31, SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42,
synthetic ferrierites, mordenite, offretite, erionite, and
chabazite and hydrodewaxing the hydrotreated feedstock under
hydrodewaxing conditions, said dewaxing catalyst including a metal
hydrogenation component which is at least one Group 6 metal, at
least one Group 8-10 metal, or mixtures of Group 6 and Group 8-10
metals, said hydrodewaxing zone also containing a second dewaxing
catalyst wherein the second dewaxing catalyst is tolerant of the
sulfur- and nitrogen-containing contaminants.
9. The process of claim 8 wherein the hydrotreating conditions
temperatures of 315-425.degree. C., pressures of 2170-20786 kPa,
Liquid Hourly Space Velocities (LHSV) of 0.1-10 and hydrogen treat
rates of 89-1780 m.sup.3/m.sup.3.
10. The process of claim 8 wherein the metal hydrogenation
component is Pt, Pd or mixtures thereof.
11. The process of claim 8 wherein the hydrodewaxing conditions
include a temperature of 360 to 425.degree. C., hydrogen pressures
of from 2859-20786 kPa, liquid hourly space velocities of 0.1 to 10
LHSV and hydrogen treat gas rates of from 53.4-1780
m.sup.3/m.sup.3.
12. The process of claim 8 further comprising a hydrofinishing step
following step (b).
13. The process of claim 8 wherein the second dewaxing catalyst is
ZSM-5 or zeolite beta.
14. The process of claim 8 wherein the dewaxing catalyst contains
ZSM-48.
15. An integrated process for dewaxing a raffinate feedstock
containing up to 20,000 ppmw sulfur and up to 1000 ppmw nitrogen
which comprises: (a) contacting the feedstock with a dewaxing
catalyst including at least one of ZSM-48, ZSM-22, ZSM-23, ZSM-5,
ZSM-35, Beta, SSZ-31,SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42,
synthetic ferrierites, mordenite, offretite, erionite, and
chabazite under hydrodewaxing conditions, said dewaxing catalyst
including a metal hydrogenation component which is at least one
Group 6 metal, at least one Group 8-10 metal, or mixtures of Group
6 and Group 8-10 metals, to form a hydrodewaxed product, and (b)
passing at least a portion of the hydrodewaxed product and gaseous
components from step (b) to a hydrofinishing zone and
hydrofinishing the hydrodewaxed product under hydrofinishing
conditions.
16. The process of claim 15 wherein the metal hydrogenation
component is Pt, Pd or mixtures thereof.
17. The process of claim 15 wherein the hydrodewaxing conditions
include a temperature of 360 to 425.degree. C., hydrogen pressures
of from 2859-20786 kPa, liquid hourly space velocities of 0.1 to 10
LHSV and hydrogen treat gas rates of from 53.4-1780
m.sup.3/m.sup.3.
18. The process of claim 15 wherein the hydrofinishing conditions
include temperatures of 150-350.degree. C., pressures of 100-3000
psig (790-20786 kPa), LHSV of 0.1-20, and treat gas rates of
300-10000 scf/bbl (53-1780 m.sup.3/m.sup.3).
19. The process of claim 15 wherein the dewaxing catalyst includes
ZSM-48.
20. An integrated process for dewaxing a raffinate feed which
comprises: (a) solvent dewaxing the raffinate to form a raffinate
and a slack wax, (b) deoiling the slack wax to produce a foots oil,
(c) contacting the foots oil with a hydrotreating catalyst under
hydrotreating conditions to produce a hydrotreated foots oil and
gaseous nitrogen- and sulfur-containing contaminants and (d)
passing at least a portion of the hydrotreated foots oil and
gaseous sulfur- and nitrogen-containing contaminants from step (c)
without disengagement to a hydrodewaxing zone containing a dewaxing
catalyst including at least one of ZSM-48, ZSM-22, ZSM-23, ZSM-5,
ZSM-35, Beta, SSZ-31,SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42,
synthetic ferrierites, mordenite, offretite, erionite, and
chabazite and hydrodewaxing the hydrotreated foots oil under
hydrodewaxing conditions, said dewaxing catalyst including a metal
hydrogenation component which is at least one Group 6 metal, at
least one Group 8-10 metal, or mixtures of Group 6 and Group 8-10
metals to from a hydrodewaxed product.
21. The process of claim 20 wherein the hydrotreating conditions
temperatures of 315-425.degree. C., pressures of 2170-20786 kPa,
Liquid Hourly Space Velocities (LHSV) of 0.1-10 and hydrogen treat
rates of 89-1780 m.sup.3/m.sup.3.
22. The process of claim 20 wherein the metal hydrogenation
component is Pt, Pd or mixtures thereof.
23. The process of claim 20 wherein the hydrodewaxing conditions
include a temperature of 360 to 425.degree. C., hydrogen pressures
of from 2859-20786 kPa, liquid hourly space velocities of 0.1 to 10
LHSV and hydrogen treat gas rates of from 53.4-1780
m.sup.3/m.sup.3.
24. The process of claim 20 further comprising a hydrofinishing
step following step (c).
25. The process of claim 20 wherein the dewaxing catalyst includes
ZSM-48.
26. An integrated process for dewaxing a feedstock containing up to
20,000 ppmw sulfur and up to 1000 ppmw nitrogen comprises: (a)
blending a raffinate feedstock and at least one of a slack wax or
foots oil to form a blended feedstock, (b) contacting the blended
feedstock with a hydrotreating catalyst under hydrotreating
conditions to produce a hydrotreated feedstock and gaseous
nitrogen- and sulfur-containing contaminants, and (c) passing at
least a portion of the hydrotreated feedstock and gaseous
components from step (b) without disengagement to a hydrodewaxing
zone containing a dewaxing catalyst including at least one of
ZSM-48, ZSM-22, ZSM-23, ZSM-5, ZSM-35, Beta, SSZ-31,SAPO-11,
SAPO-31, SAPO-41, MAPO-11, ECR-42, synthetic ferrierites,
mordenite, offretite, erionite, and chabazite and hydrodewaxing the
hydrotreated feedstock under hydrodewaxing conditions, said
dewaxing catalyst including a metal hydrogenation component which
is at least one Group 6 metal, at least one Group 8-10 metal, or
mixtures of Group 6 and Group 8-10 metals, to form a hydrodewaxed
product.
27. The process of claim 26 wherein the hydrotreating conditions
temperatures of 315-425.degree. C., pressures of 2170-20786 kPa,
Liquid Hourly Space Velocities (LHSV) of 0.1-10 and hydrogen treat
rates of 89-1780 m.sup.3/m.sup.3.
28. The process of claim 26 wherein the metal hydrogenation
component is Pt, Pd or mixtures thereof.
29. The process of claim 26 wherein the hydrodewaxing conditions
include a temperature of 360 to 425.degree. C., hydrogen pressures
of from 2859-20786 kPa, liquid hourly space velocities of 0.1 to 10
LHSV and hydrogen treat gas rates of from 53.4-1780
m.sup.3/m.sup.3.
30. The process of claim 26 further comprising a hydrofinishing
step following step (c).
31. The process of claim 26 wherein the dewaxing catalyst includes
ZSM-48.
32. An integrated process for dewaxing a raffinate feedstock
containing up to 20,000 ppmw sulfur and up to 1000 ppmw nitrogen
which comprises: (a) contacting the feedstock with a hydrotreating
catalyst under hydrotreating conditions to produce a hydrotreated
feedstock and gaseous nitrogen- and sulfur-containing contaminants,
and (b) passing at least a portion of the hydrotreated feedstock
and gaseous components from step (a) without disengagement to a
hydrodewaxing zone containing a ZSM-48 dewaxing catalyst and
hydrodewaxing the hydrotreated feedstock under hydrodewaxing
conditions, said dewaxing catalyst including a metal hydrogenation
component which is at least one Group 6 metal, at least one Group
8-10 metal, or mixtures of Group 6 and Group 8-10 metals, to form a
hydrodewaxed product.
33. The process of claim 32 wherein the hydrotreating conditions
temperatures of 315-425.degree. C., pressures of 2170-20786 kPa,
Liquid Hourly Space Velocities (LHSV) of 0.1-10 and hydrogen treat
rates of 89-1780 m.sup.3/m.sup.3.
34. The process of claim 32 wherein the metal hydrogenation
component is Pt, Pd or mixtures thereof.
35. The process of claim 32 wherein the hydrodewaxing conditions
include a temperature of 360 to 425.degree. C., hydrogen pressures
of from 2859-20786 kPa, liquid hourly space velocities of 0.1 to 10
LHSV and hydrogen treat gas rates of from 53.4-1780
m.sup.3/m.sup.3.
36. The process of claim 32 further comprising a hydrofinishing
step following step (b).
37. The process of claim 32 wherein the dewaxing catalyst further
comprises a second dewaxing catalyst.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims benefit of U.S. Provisional
Patent Applications Serial Nos. 60/416,866 filed Oct. 8, 2002, and
60/490,155 filed Jul. 25, 2003.
FIELD OF THE INVENTION
[0002] This invention related to an integrated catalytic
hydrodewaxing process for hydrocarbon feeds. More particularly, a
feedstock containing sulfur and nitrogen contaminants is subject to
a process including hydrotreating, hydrodewaxing and/or
hydrofinishing without disengagement between the process steps.
BACKGROUND OF THE INVENTION
[0003] Dewaxing of hydrocarbon feedstocks is conventionally used to
improve the flow properties of the feed, typically by lowering the
pour point. Dewaxing catalysts remove waxy components of feeds by
either selective hydrocracking or isomerization. The selectivity of
dewaxing catalysts may be improved by employing constrained
intermediate pore molecular sieves. The activity of such selective
catalysts may be improved by employing a metal
hydrogenation/dehydrogenation component.
[0004] One problem encountered with dewaxing catalysts is that they
are sensitive to environments containing sulfur and/or nitrogen
contaminants. Such contaminants negatively impact catalyst
activity, catalyst aging and catalyst selectivity. Thus it is
common to employ a hydrotreating and/or hydrocracking step prior to
the dewaxing step to convert nitrogen and sulfur containing
contaminants to ammonia and hydrogen sulfide and to remove these
gaseous contaminants from the process prior to the dewaxing
step.
[0005] The disadvantage of processes involving separate dewaxing
and hydrofinishing steps is that considerable capital investment is
involved in the equipment for these steps. Processes which are
directed to lubricants with high VI and low pour points and which
combine hydrotreating with conventional dewaxing catalysts such as
ZSM-5 run a substantial yield debit since the hydrotreating step is
run at more severe conditions in order to compensate for VI loss
during hydrodewaxing. More recent dewaxing catalysts which function
by isomerization typically require clean feeds, i.e., feeds with
very low concentrations of sulfur and nitrogen contaminants. When
combined with a pre-hydrotreating step, separation and stripping of
gaseous contaminants are normally required to protect catalyst
activity.
[0006] It would be desirable to have an integrated process using
dewaxing catalysts which are capable of operating in environments
containing substantial concentrations of sulfur- and or
nitrogen-containing contaminants while maintaining catalyst
properties such as selectivity, activity and aging which process
functions without the need for a disengagement step to remove
gaseous sulfur- and nitrogen containing contaminants.
SUMMARY OF THE INVENTION
[0007] The present invention relates to an integrated dewaxing
process capable of operating with highly contaminated feedstocks.
The integrated process for dewaxing a raffinate feedstock
containing up to 20,000 ppmw sulfur and up to 1000 ppmw nitrogen
comprises: (a) contacting the feedstock with a hydrotreating
catalyst under hydrotreating conditions to produce a hydrotreated
feedstock and gaseous nitrogen- and sulfur-containing contaminants,
and (b) passing at least a portion of the hydrotreated feedstock
and gaseous components from step (a) without disengagement to a
hydrodewaxing zone containing a dewaxing catalyst including at
least one of ZSM-48, ZSM-22, ZSM-23, ZSM-5, ZSM-35, Beta,
SSZ-31,SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42, synthetic
ferrierites, mordenite, offretite, erionite, and chabazite and
hydrodewaxing the hydrotreated feedstock under hydrodewaxing
conditions, said dewaxing catalyst including a metal hydrogenation
component which is at least one Group 6 metal, at least one Group
8-10 metal, or mixtures of Group 6 and Group 8-10 metals, to form a
hydrodewaxed product. As used herein, ZSM-48 includes EU-2, EU-11
and ZBM-20 which are structurally equivalent to ZSM-48.
[0008] Another embodiment relates to an integrated process for
dewaxing a raffinate feedstock containing up to 20,000 ppmw sulfur
and up to 1000 ppmw nitrogen which comprises: (a) contacting the
feedstock with a hydrotreating catalyst under hydrotreating
conditions to produce a hydrotreated feedstock and gaseous
nitrogen- and sulfur-containing contaminants, (b) passing at least
a portion of the hydrotreated feedstock and gaseous sulfur- and
nitrogen-containing contaminants from step (a) without
disengagement to a hydrodewaxing zone containing a dewaxing
catalyst including at least one of ZSM-48, ZSM-22, ZSM-23, ZSM-5,
ZSM-35, Beta, SSZ-31, SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42,
synthetic ferrierites, mordenite, offretite, erionite, and
chabazite and hydrodewaxing the hydrotreated feedstock under
hydrodewaxing conditions, said dewaxing catalyst including a metal
hydrogenation component which is at least one Group 6 metal, at
least one Group 8-10 metal, or mixtures of Group 6 and Group 8-10
metals, said hydrodewaxing zone also containing a second dewaxing
catalyst wherein the second dewaxing catalyst is tolerant of the
sulfur- and nitrogen containing contaminants.
[0009] Yet another embodiment relates to an integrated process for
dewaxing a raffinate feedstock containing up to 20,000 ppmw sulfur
and up to 1000 ppmw nitrogen which comprises: (a) contacting the
feedstock with a dewaxing catalyst including at least one of
ZSM-48, ZSM-22, ZSM-23, ZSM-5, ZSM-35, Beta, SSZ-31,SAPO-11,
SAPO-31, SAPO-41, MAPO-11, ECR-42, synthetic ferrierites,
mordenite, offretite, erionite, and chabazite under hydrodewaxing
conditions, said dewaxing catalyst including a metal hydrogenation
component which is at least one Group 6 metal, at least one Group
8-10 metal, or mixtures of Group 6 and Group 8-10 metals, to form a
hydrodewaxed product, and (b) passing at least a portion of the
hydrodewaxed product and gaseous components from step (b) to a
hydrofinishing zone and hydrofinishing the hydrodewaxed product
under hydrofinishing conditions.
[0010] A still further embodiment relates to an integrated process
for dewaxing a raffinate feed which comprises: (a) solvent dewaxing
the raffinate to form a raffinate and a slack wax, (b) deoiling the
slack wax to produce a foots oil, (c) contacting the foots oil with
a hydrotreating catalyst under hydrotreating conditions to produce
a hydrotreated foots oil and gaseous nitrogen- and
sulfur-containing contaminants and (d) passing at least a portion
of the hydrotreated foots oil and gaseous sulfur- and
nitrogen-containing contaminants from step (c) without
disengagement to a hydrodewaxing zone containing a dewaxing
catalyst including at least one of ZSM-48, ZSM-22, ZSM-23, ZSM-5,
ZSM-35, Beta, SSZ-31, SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42,
synthetic ferrierites, mordenite, offretite, erionite, and
chabazite and hydrodewaxing the hydrotreated foots oil under
hydrodewaxing conditions, said dewaxing catalyst including a metal
hydrogenation component which is at least one Group 6 metal, at
least one Group 8-10 metal, or mixtures of Group 6 and Group 8-10
metals to from a hydrodewaxed product.
[0011] Another embodiment relates to an integrated process for
dewaxing a feedstock containing up to 20,000 ppmw sulfur and up to
1000 ppmw nitrogen comprises: (a) blending a raffinate feedstock
and at least one of a slack wax or foots oil to form a blended
feedstock, (b) contacting the blended feedstock with a
hydrotreating catalyst under hydrotreating conditions to produce a
hydrotreated feedstock and gaseous nitrogen- and sulfur-containing
contaminants, and (c) passing at least a portion of the
hydrotreated feedstock and gaseous components from step (b) without
disengagement to a hydrodewaxing zone containing a dewaxing
catalyst including at least one of ZSM-48, ZSM-22, ZSM-23, ZSM-5,
ZSM-35, Beta, SSZ-31,SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42,
synthetic ferrierites, mordenite, offretite, erionite, and
chabazite and hydrodewaxing the hydrotreated feedstock under
hydrodewaxing conditions, said dewaxing catalyst including a metal
hydrogenation component which is at least one Group 6 metal, at
least one Group 8-10 metal, or mixtures of Group 6 and Group 8-10
metals, to form a hydrodewaxed product.
DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a graph showing average reactor temperature at
given pour point.
[0013] FIG. 2 is a graph showing polar tolerance of the
catalyst.
[0014] FIG. 3 is a graph showing lube yields for dewaxing a medium
neutral foots oil over a Crosfield hydrotreating catalyst followed
by a Pt/ZSM-48 dewaxing catalyst.
[0015] FIG. 4 is a graph showing viscosity of the dewaxed medium
neutral foots oil.
[0016] FIG. 5 is a graph showing VI of the dewaxed medium neutral
foots oil.
[0017] FIG. 6 is a graph showing cloud points of the dewaxed medium
neutral foots oil.
DETAILED DESCRIPTION OF THE INVENTION
[0018] In the present process, the steps are integrated, i.e., a
process that incorporates a sequence of steps which are
interrelated and dependent on either earlier or later steps, said
steps occurring without disengagement between the sequence of
steps.
[0019] Dewaxing catalysts which are isomerization catalysts are
normally shape selective intermediate pore molecular sieves loaded
with a hydrogenation metal, particularly noble metals. However,
such isomerization dewaxing catalysts are considered susceptible to
poisoning by sulfur- and nitrogen-containing contaminants such as
NH.sub.3 and H.sub.2S. They are thus normally protected by a
preceding treatment to remove such poisons. An example of such
pre-treatment is conversion of sulfur- and nitrogen-containing
contaminants to H.sub.2S and NH.sub.3, respectively, by
hydrotreatment. However, hydrotreatement is followed by
disengagement to remove (strip) the sulfur- and nitrogen-containing
contaminants prior to dewaxing so as not to poison the
catalyst.
[0020] Feeds for the present integrated dewaxing process include
raffinates. Raffinates are obtained from solvent extraction
processes that selectively dissolve the aromatic components in an
extract phase while leaving the more paraffinic components in a
raffinate phase. Naphthenes are distributed between the extract and
raffinate phases. Typical solvents for solvent extraction include
phenol, furfural and N-methyl pyrrolidone. By controlling the
solvent to oil ratio, extraction temperature and method of
contacting feed to be extracted with solvent, one can control the
degree of separation between the extract and raffinate phases. The
raffinates may be wide cut or narrow cut.
[0021] The raffinates from solvent extraction may be further
subject to solvent dewaxing to separate a lube oil fraction and a
slack wax. Solvent dewaxing may be accomplished by treating the
raffinates with a solvent such as propane, ketones and mixtures of
ketones with aromatics such as benzene, toluene and/or xylene and
chilling to crystallize and separate wax molecules. The resulting
slack wax is then deoiled to separate a foots oil (soft wax) from
microcrystalline wax (hard wax). The slack wax or foots oil may be
blended with a raffinate to form a blended feedstock. The ratio of
raffinate to slack wax or foots oil in the blended feedstock may
range from 99:1 to 1:99.
[0022] The raffinate, slack wax or foots oil feeds are
characterized in that they may contain high levels up to 20,000
ppmw of sulfur containing contaminants and up to 1,000 ppmw of
nitrogen containing contaminants.
[0023] An important purpose of hydrotreating is to reduce the
sulfur and nitrogen content of a feed. Hydrotreating for the
present process is not primarily concerned with boiling point
conversion of the feed. Hydrotreating catalysts usually contain at
least one of Group 6 and Group 8-10 metal (Groups based on the
IUPAC Periodic Table format having groups from 1 to 18), on a less
acidic support such as alumina or silica. Catalysts may also be
bulk metal catalysts wherein the amount of metal may be 30 wt. % or
more. Examples include Ni/Mo, Co/Mo and Ni/W catalysts. Preferred
hydrotreating catalysts are low acidity, high metals content
catalysts such as KF-848 (Akzo Nobel), DN 190 (Criterion catalysts)
and RT 721 (Akzo Nobel). The amount of metal is from 0.1 to 95 wt.
%, based on catalyst. Hydrotreating conditions include temperatures
of 315 -425.degree. C., pressures of 2170-20786 kPa (300-3000
psig), liquid hourly space velocities (LHSV) of 0.1-10 and hydrogen
treat rates of 89-1780 m.sup.3/m.sup.3 (500-10,000 scf/bbl).
[0024] If a hydrotreating step is used prior to the dewaxing step
of the present process, there is no need for disengagement between
the hydrotreating and dewaxing step. Disengagement involves
depressurization, stripping and repressurization and therefor
requires expensive pumps, separators and heaters. This disadvantage
is avoided because the present dewaxing catalysts can operate in a
sour environment. In the case of raffinates, it may be possible to
simply pass the raffinate directly to the dewaxing step without any
prior hydrotreatment.
[0025] It has been discovered that certain dewaxing catalysts can
function in a sour environment. The present dewaxing catalysts
include ZSM-48, ZSM-22, ZSM-23, ZSM-5, ZSM-35, Beta, SSZ-31,
SAPO-11, SAPO-31, SAPO-41, MAPO-11, ECR-42, synthetic ferrierites,
mordenite, offretite, erionite, and chabazite, with ZSM-48, ZSM-22,
ZSM-5, ZSM-23 and ZSM-35 being preferred while ZSM-48 is a more
preferred embodiment. ZSM-48 is a unidimensional intermediate pore
10 ring zeolite having a pore size of 5.3 .ANG..times.5.6 .ANG..
ZSM-48 is commercially available and its preparation is described
in U.S. Pat. Nos. 4,397,827, 4,448,675 and 5,075,269. ZSM-22 is
described in U.S. Pat. No. 4,556,477, ZSM-23 in U.S. Pat. No.
4,076,342 and ZSM-35 in U.S. Pat. No. 4,016,245.
[0026] The dewaxing catalysts are bifunctional, i.e., they are
loaded with a metal hydrogenation component, which is at least one
Group 6 metal, at least one Group 8-10 metal, or mixtures thereof.
Preferred metals are Groups 9-10 metals. Especially preferred are
Groups 9-10 noble metals such as Pt, Pd or mixtures thereof (based
on the IUPAC Periodic Table format having Groups from 1 to 18).
These metals are loaded at the rate of 0.1 to 30 wt. %, based on
catalyst. Catalyst preparation and metal loading methods are
described for example in U.S. Pat. No. 6,294,077, and include for
example ion exchange and impregnation using decomposable metal
salts. Metal dispersion techniques and catalyst particle size
control are described in U.S. Pat. No.5,282,958. Catalysts with
small particle size and well-dispersed metal are preferred.
[0027] The dewaxing catalysts are typically composited with binder
materials which are resistant to high temperatures which may be
employed under dewaxing conditions to form a finished dewaxing
catalyst or may be binderless (self-bound). The binder materials
are usually inorganic oxides such as silica, alumina,
silica-aluminas, binary combinations of silicas with other metal
oxides such as titania, magnesia, thoria, zirconia and the like and
tertiary combinations of these oxides such as silica-alumina
-thoria and silica-alumina magnesia. The amount of molecular sieve
in the finished dewaxing catalyst is from 10 to 100, preferably 35
to 100 wt. %, based on catalyst. Such catalysts are formed by
methods such spray drying, extrusion and the like. The dewaxing
catalyst may be used in the sulfided or unsulfided form, and is
preferably in the sulfided form.
[0028] The temperature for the present dewaxing process is in the
range from 360 to 425.degree. C . Due to the catalyst structure,
these temperatures may be higher than the temperatures normally
used for catalytic dewaxing without the cracking that might
otherwise be expected from such higher temperatures. Other process
conditions include hydrogen pressures of from 2859-20786 kPa (400
to 3000 psig), liquid hourly space velocities of 0.1 to 10 LHSV and
hydrogen treat gas rates of from 53.4-1780 m.sup.3/m.sup.3 (300 to
10,000 scf/bbl).
[0029] The hydrodewaxing catalyst may contain a second catalytic
component which may be admixed with the ZSM-48 dewaxing catalyst or
may be in a stacked (layered) configuration with the second
component in the upper layer. The second catalyst is tolerant of
sulfur- and nitrogen-containing contaminants. Typical catalysts
that are tolerant of such contaminants include ZSM-5 and larger
pore catalysts such as zeolite beta. A convenient measure of the
extent to which a dewaxing catalyst provides control molecules of
varying sizes to its internal structure is the Constraint Index of
the zeolite. Zeolites which provide a highly restricted access to
and egress from its internal structure have a high value for the
Constraint Index, and zeolites of this kind usually have pores of
small size. On the other hand, zeolites which provide relatively
free access to the internal zeolite structure have a low value for
the Constraint Index. The method by which Constraint Index is
determined is described fully in U.S. Pat. No.4,016,218, to which
reference is made for details of the method. Large pore zeolites
having Constraint Indices less than 1 include TEA mordenite (0.4),
dealuminized Y (0.5), ZSM-4 (0.5), ZSM-20 (0.5), mordenite (0.5),
REY (0.4) and ultrastable Y. Zeolite beta is also within the scope
of large pore zeolites. The second catalytic component may also be
acidic porous amorphous materials, such as amorphous
aluminosilicate, halogenated alumina, acidic clay, alumina or
silica-alumina.
[0030] At least a portion of the products from the hydrodewaxing
zone or step may then be passed to a hydrofinishing step again
without the need of disengagement between the hydrodewaxing and
hydrofinishing steps. Catalysts for hydrofinishing can the same as
those used for the preliminary hydrotreating step, if any, i.e.,
those containing at least one of Group 6 and Group 8-10 metal on a
support such as alumina or silica. Examples include Ni/Mo, Co/Mo
and Ni/W catalysts. Preferred hydrotreating catalysts include
catalyst such as KF-840, KF-848 (Akzo Nobel), DN 190 (Criterion
catalysts) and RT 721 (Akzo Nobel).
[0031] The hydrofinishing catalyst may also be a crystalline
mesoporous material belonging to the M41 S class or family of
catalysts. The M41S family of catalysts are crystalline mesoporous
materials having high silica contents whose preparation is further
described in J. Amer. Chem. Soc., 1992, 114, 10834. Examples
included MCM-41, MCM-48 and MCM-50. A preferred member of this
class is MCM-41 whose preparation is described in U.S. Pat. No.
5,098,684. MCM-41 is characterized by having a hexagonal crystal
structure with a unidimensional arrangement of pores having a cell
diameter greater than 13 Angstroms. The physical structure of
MCM-41 is like a bundle of straws wherein the opening of the straws
(the cell diameter of the pores) ranges from 13 to I 00+Angstroms.
MCM-48 has a cubic symmetry and is described for example is U.S.
Pat. No. 5,198,203 whereas MCM-50 has a lamellar structure and is
described in U.S. Pat. No. 5,246,689.
[0032] The amount of metal is from 0.1 to 5 wt. %, preferably 0.2
to 2 wt. %, based on catalyst. Hydrofinishing conditions include
temperatures of 150-350.degree. C., preferably 180-300.degree. C.,
pressures of 100-3000 psig (790-20786 kPa), preferably 50-2500 psig
(1135-17339 kPa), LHSV of 0.1-20, preferably 0.2-15 and treat gas
rates of 300-10000 scf/bbl (53-1780 m.sup.3/m.sup.3), preferably
450-5000 scfB (80-890 m.sup.3/m.sup.3).
[0033] If the raffinate feed is passed directly to hydrodewaxing
without a preliminary hydrotreating step, then dewaxed product from
hydrodewaxing is passed to hydrofinishing without disengagement.
The preferred hydrofinishing conditions will include a temperature
range of from 150-300.degree. C.
[0034] The product from the hydrofinishing step is typically passed
to a separator which may include stripping and/or fractionation. In
the separation zone, sulfur- and nitrogen containing contaminants,
especially hydrogen sulfide and ammonia, are separated together
with other gaseous components from liquid product. The liquid
product may be fractionated to obtain various cuts of lubricating
oil products based on boiling range.
[0035] The process sequence may include the following steps in
various combinations. A waxy feed is first solvent extracted to
separate a raffinate and an extract. The raffinate may then be sent
directly to hydrotreating, may be hydrodewaxed directly or may be
solvent dewaxed to produce a lubricating oil and a slack wax. Upon
deoiling, the slack wax yields a hard wax and foots oil which may
then be sent to hydrotreating.
[0036] In the sequence raffinate to hydrotreating to hydrodewaxing
and optionally hydrofinishing, there is no disengagement between
any of the process sequence steps. The hydrotreating and
hydrodewaxing steps may take place sequentially in separate
reactors or may occur as stacked beds in a single reactor. Any
hydrofinishing step will occur in a separate reactor. If the
hydrodewaxing step involves more than one dewaxing catalyst, then
the hydrodewaxing step may involve a mixture of dewaxing catalysts
in a single reactor, stacked beds in a single reactor, or separate
reactors in sequence each containing a dewaxing catalyst.
[0037] The process sequence involving foots oils may include
hydrotreating, hydrodewaxing and optionally hydrotreating. As in
the case of raffinates, the sequence may take place sequentially in
separate reactors or may occur as stacked beds in a single
reactor.
[0038] The invention is further illustrated by the following
examples which are not intended as limiting.
EXAMPLES
Example 1
[0039] Table 1compares three processing configurations for dewaxing
a 260 Neutral raffinate containing 6680 wppm sulphur and 50.6 wppm
nitrogen and a dry wax content of 16.75 wt. % on feed at -18 pour
point. Column A illustrates the properties of a dewaxed oil
obtained by solvent dewaxing with methylisobutyl ketone at a feed
to solvent ratio of 3:1, the 260 Neutral raffinate. Prior to
solvent dewaxing, the raffinate had been hydrotreated over an Akzo
KF-848 hydrotreated catalyst at an average reactor temperature of
350.degree. C., 0.53 LHSV, at a treat gas rate of 2600 SCF
H.sub.2/bbl of feed and 1800psig. The sulphur and nitrogen contents
of the hydrotreated raffinate were less than 2 wppm.
1TABLE 1 B A Hydro- Hydro- treating + C treating + depressur-
Untreated Solvent ization + feed + Process Dewaxing hydrodewaxing
hydrodewaxing HDW Average Reactor n/a 310 370 Temperature, .degree.
C. Yield of 370.degree. C. + DWO 61.2 70.2 65.1 on Raw Feed, wt %
Dewaxed Oil Properties Viscosity, cSt at 100.degree. C. 6.1 5.6 5.4
Viscosity, cSt at 40.degree. C. 36.8 31.4 29.7 Viscosity Index 113
120 117 Pour Point, .degree. C. -17 -17 -16 Cloud Point, .degree.
C. -14 -6 -13 Cloud -Pour Spread, .degree. C. 3 11 3
[0040] Column B illustrates the properties of the product made by
hydrotreating the 260N raffinate over Akzo KF 848 at an average
reactor temperature of 350.degree. C., 0.53LHSV, 1800 psig and at a
treat gas rate of 2600SCF H.sub.2/bll of feed but followed by
catalytic dewaxing over a hydrodewaxing catalyst containing ZSM-48.
The process conditions during hydrodewaxing were 0.76 LHSV,
1650SCF/B H.sub.2, and 1800psig. In this example the gas phase
polar species (e.g., ammonia and hydrogen sulphide) were removed
before the hydrodewaxing step. Comparing the products in columns A
and B it can be seen that the yield and VI of product after
hydrodewaxing in increased over that obtained by solvent dewaxing
at constant pour point. One other item to note is that the
cloud-pour spread of the hydrodewaxed product is considerably
larger than that of the solvent dewaxed product.
[0041] Column C illustrates the properties of the product made by
hydrotreating the 260N raffinate over Akzo KF 848 at an average
reactor temperature of 350.degree. C., 0.53LHSV and at a treat gas
rate of 2600SCF H.sub.2/bbl of feed but hydrodewaxing over a
hydrodewaxing catalyst containing ZSM-48. The process conditions in
the hydrodewaxing stage were 0.76 LHSV, 1650SCF/B H.sub.2, and 1800
psig. In this illustration, the gas phase polar species generated
during the hydrotreating stage, were cascaded with the hydrogen
over the hydrodewaxing stage which required that the temperature of
the dewaxing stage was higher than that in column B. Comparing the
products in columns A and B with the product in column C, it can be
seen that the yield and VI of product after hydrodewaxing in
increased over that obtained by solvent dewaxing. It is noted that
the cloud-pour spread of the hydrodewaxed product made at elevated
reactor temperature in a sour gas environment is similar to that of
the solvent dewaxed product.
Example 2
[0042] Table 2 compares three processing configurations for
dewaxing a 130 Neutral raffinate containing 2500 wppm sulphur and
25 wppm nitrogen and a dry wax content of 16.44 wt. % on feed at
-16.degree. C. pourpoint. Column A illustrates the properties of a
dewaxed oil obtained by solvent dewaxing with methylisobutyl ketone
at a feed to solvent ratio of 3:1, the 130 Neutral raffinate. Prior
to solvent dewaxing, the raffinate had been hydrotreated over an
Akzo KF848 hydrotreated catalyst at an average reactor temperature
of 350.degree. C., 0.53LHSV, at a treat gas rate of 2600SCF
H.sub.2/bll of feed and 1800 psig. The sulphur and nitrogen
contents of the hydrotreated raffinate were less than 2 wppm.
2TABLE 2 B A Hydro- Hydro- treating + C treating + depressur-
Untreated Solvent ization + feed + Process Dewaxing hydrodewaxing
hydrodewaxing HDW Average Reactor n/a 310 370 Temperature, .degree.
C. Yield of 370.degree. C. + DWO 57.12 57.6 44.23 on Raw Feed, wt %
Dewaxed Oil Properties Viscosity, cSt at 100.degree. C. 4.28 4.04
3.654 Viscosity, cSt at 40.degree. C. 20.752 18.352 15.823
Viscosity Index 112 120 116 Pour Point, .degree. C. -27 -27 -26
Cloud Point, .degree. C. -28 -17 -24 Cloud -Pour spread, .degree.
C. -- 10 2
[0043] Column B illustrates the properties of the product made by
hydrotreating the 130N raffinate over Akzo KF 848 at an average
reactor temperature of 350.degree. C., 0.53LHSV, 1800 psig and at a
treat gas rate of 2600SCF H.sub.2/bll of feed but followed by
catalytic dewaxing over a hydrodewaxing catalyst containing ZSM-48.
The process conditions during hydrodewaxing were 0.76 LHSV,
1650SCF/B H.sub.2, and 1800 psig. In this example the gas phase
polar species (e.g., ammonia and hydrogen sulphide) were removed
before the hydrodewaxing step. Comparing the products in columns A
and B it can be seen that the yield and VI of product after
hydrodewaxing in increased over that obtained by solvent dewaxing
at constant pour point. One other item to note is that the
cloud-pour spread of the hydrodewaxed product is considerably
larger than that of the solvent dewaxed product.
[0044] Column C illustrates the properties of the product made by
hydrotreating the 130N raffinate over Akzo KF 848 at an average
reactor temperature of 350.degree. C., 0.53LHSV and at a treat gas
rate of 2600SCF H.sub.2/bll of feed but hydrodewaxing over a
hydrodewaxing catalyst containing ZSM-48. The process conditions in
the hydrodewaxing stage were 0.76 LHSV, 1650SCF/B H.sub.2, and 1800
psig. In this illustration, the gas phase polar species generated
during the hydrotreating stage, were cascaded with the hydrogen
over the hydrodewaxing stage which required that the temperature of
the dewaxing stage was higher than that in column B. Comparing the
products in columns A and B with the product in column C, it can be
seen that the yield and VI of product after hydrodewaxing increased
over that obtained by solvent dewaxing at the same pour point. It
is noted that the cloud-pour spread of the hydrodewaxed product
made at elevated reactor temperature in a sour gas environment,
column C, is similar to that of the solvent dewaxed product.
Example 3
[0045] This example illustrates the effect of treat gas rate on the
hydrodewaxing stage operating in a sour gas environment. The 130N
raffinate was hydrotreated over Akzo KF 848 at an average reactor
temperature of 350.degree. C., 0.53LHSV and at a treat gas rate of
2600SCF H.sub.2/bll of feed and hydrodewaxing over a hydrodewaxing
catalyst containing ZSM-48. The process conditions in the
hydrodewaxing stage were 0.76 LHSV, 1650 to 2500SCF/B H.sub.2, and
1800 psig. In this illustration, the gas phase polar species
generated during the hydrotreating stage were cascaded with the
hydrogen over the hydrodewaxing stage. The hydrodewaxing catalyst
is a ZSM-48 bound with alumina (35/65 wt ratio respectively)
operating under a series of conditions shown in FIG. 1. The figure
illustrates that by increasing the treat gas rate from
1650SCFH.sub.2/B feed to 2100 and then to 2500SCFH.sub.2/B feed,
the Average Reactor Temperature required to maintain a feed pour
point of 10.degree. F. decreases from 690 to 680.degree. F. for a
130N raffinate.
Example 4
[0046] This example illustrates the application of a hydrodewaxing
catalyst catalyst, containing ZSM-48 and alumina 65/35 wt %, for
hydrodewaxing a 130N waxy raffinate containing, 7270 wppm sulfur
and 32.6 wppm of total nitrogen, and a dry wax content of 17 wt %
on feed at a pour point of -18Cat 400 psig H.sub.2 and 2500SCF/B
H.sub.2 without pre-hydrotreating but having a hydrofinishing
step.
[0047] The processing conditions were as listed in Table 3 and the
product quality data in Table 4.
3 TABLE 3 Pressure Gas Rate, Average Reactor LHSV Psig SCF/B feed
Temperature, .degree. C. Hydrodewaxing 0.5-1.0 400 2500 350-380
Hydrofinishing 0.5-1.0 400 2500 290
[0048]
4TABLE 4 B A Untreated feed + Process Solvent Dewaxing
hydrodewaxing HDW Average Reactor n/a 370 Temperature, .degree. C.
Yield of 370.degree. C. + DWO 82.9 72.4 on Raw Feed, wt % Dewaxed
Oil Properties Viscosity, cSt at 100.degree. C. 4.93 4.44
Viscosity, cSt at 40.degree. C. 28.45 23.06 Viscosity Index 94 102
Pour Point, .degree. C. -19 -19
[0049] Table 4 illustrates that hydrodewaxing the unhydrotreated
waxy raffinate gives a 370.degree. C.+ product having an eight
point higher VI than that produced by solvent dewaxing.
[0050] FIG. 2 illustrates the polar tolerance of the catalyst given
50 days on stream with the unhydrotreated 130N Raffinate
feedstock.
Example 5
[0051] This Example illustrates the cascade dewaxing of a foots oil
feed. Two soft wax feeds, a medium neutral Foots oil (MNFO) and
light neutral Foots oil (LNFO), were used for the dewaxing study.
The properties of the feeds are summarized as follows.
5TABLE 5 Properties of Foots Oils Medium Neutral Light Neutral
Foots Feed Foots Oil Oil KV@100.degree. C., cSt 5.513 3.207
KV@40.degree. C., cSt -- 23.84 Pour Point, .degree. C. 45 36
Density, g/cc 0.8453 0.8241 N content, ppm 19 <8 S content, ppm
1851 1807 Aromatics, % 12.1 8.9 Boiling Range, .degree. F. 715-950
650-918 Oil Content, % 38.12 33.7
[0052] Two catalysts were employed for dewaxing the Foots oil
feeds. Crosfield 599 was used as a pre-hydrotreating catalyst
followed by Pt/ZSM-48 dewaxing catalyst. Crosfield 599 is a
commercial catalyst containing a mixture of NiO and MoO.sub.3
supported on alumina. The properties and metal contents of the
catalyst are shown below.
[0053] Crosfield 599: 224 m.sup.2/g (surface area), 1.37 g/cc
(particle density), 35% Al, 3.8% Ni, 17% Mo.
[0054] The dewaxing catalyst was alumina (35 wt. %) bound, ZSM-48
crystals containing 0.6 wt. % platinum.
[0055] The dewaxing experiments were performed using a microunit
equipped with two cascaded down-flow trickle bed tubular reactors
and two three-zone furnaces. The unit was heat-traced to avoid
freezing of the waxy feedstocks. To reduce feed bypassing and lower
zeolite pore diffusion resistance, the catalyst extrudates were
crushed and sized to 60-80 mesh. The first reactor was then loaded
with a mixture of 7.5 cc of the sized Crosfield 599 and 3 cc of
80-120 mesh sand. The second reactor was loaded with a mixture of
15 cc of the sized Pt/ZSM-48 and 5 cc of 80-120 mesh sand.
[0056] After pressure testing of the unit, the catalysts were dried
and reduced at 204.degree. C. (400.degree. F.) for one hour under 1
atmosphere, 255 cc/min hydrogen flow. The catalysts were then
sulfided at 371.degree. C. (700.degree. F.) for 12 h using 100
cc/min, 2% H.sub.2S in H.sub.2. The MNFO was first processed over
the cascaded Crosfield 599/Pt-ZSM-48, followed by switching feed to
the LNFO. Isomerization and dewaxing of the Foots oil feeds was
conducted under 2860-6996 kPa (400-1000 psig) H.sub.2 at 2.0
h.sup.-1 LHSV based on Crosfield 599 and 1.0 h.sup.-1 LHSV based on
Pt/ZSM-48. Hydrogen/feed ratio was set at 1015 m.sup.3/m.sup.3
(5700 scf/bbl). The dewaxing experiments were started first by
saturating the catalyst beds with feed at 204.degree. C.
(400.degree. F.), then heating the two reactors to initial
operating temperature (the two reactors were maintained at same
temperature). Material balances were carried out overnight for 16 h
after 8 h lineout. Reactors temperature was then gradually changed
to vary pour point.
[0057] Off-gas samples were analyzed by GC. Total liquid products
(TLPs) were weighed and analyzed by simulated distillation. TLPs
were distilled into initial boiling point (IBP) -166.degree. C.
(-330.degree. F.) naphtha, 166-343.degree. C. (330-650.degree. F)
distillate, and 343.degree. C.+ (650.degree. F.+) lube fractions.
The 343.degree. C.+(650.degree. F.+) lube fractions were again
analyzed by simulated distillation (Simdis) to ensure accuracy of
the actual distillation operations. The pour point and cloud point
of 343.degree. C.+ 650.degree. F.+ lubes were measured according to
corresponding ASTM D97 and D2500 methods, and their viscosities
were determined at both 40.degree. C. and 100.degree. C. according
to ASTM-D445-3 and D445-5 methods, respectively.
[0058] The dewaxing of the MNFO was carried out under 6996 kPa
(1000 psig) H.sub.2 at 2.0 h.sup.-1 LHSV based on Crosfield 599 and
1.0 h.sup.-1 LHSV based on Pt/ZSM-48. Hydrogen/feed ratio of 1015
m.sup.3/m.sup.3 (5700 scf/bbl) was used. The temperature of both
Reactor 1 (containing Crosfield 599) and Reactor 2 (containing
Pt/ZSM-48) was kept same. The dewaxed oil yields and properties are
summarized in Table 6. For further clarification, the dewaxing
results are also illustrated in FIGS. 3-6.
6TABLE 6 Lube Yield and Properties for Dewaxing the MNFO under 1000
psig H.sub.2 650.degree. F.+ Pour Cloud Temp Yield, KV@100.degree.
C. Point Point S N Tot. Arom (.degree. C.) wt % Feed (cSt) VI
(.degree. C.) (.degree. C.) (ppm) (ppm) (mmol/Kg) 354 82 5.364
141.8 18 30 29 <5 223 360 73 5.224 135.8 9 22 28 <5 227 363
67 5.342 132.8 6 17 <25 <5 230 368 60 5.436 125.8 -3 5 <25
<5 249 374 49 5.851 114.6 -27 -18 <25 <5 270 379 34 5.727
106.6 <-54 <-54 <25 <5 305
[0059] The results show that the cascaded dual catalysts system
consisting of first bed Crosfield 599 pre-hydrotreating catalyst
followed by second bed Pt/ZSM-48 dewaxing catalyst is capable of
converting the medium neutral Foots oil to high VI (>120) Group
III lube base stocks with low sulfur (<25 ppm) and nitrogen
(<5 ppm) contents. Lube yield of about 60% was obtained at
conventional pour point.
Example 6
[0060] To test the pressure effects on the catalysts performance
and lube product properties, the dewaxing of the MNFO was also
performed under 2859 kPa (400 psig) H.sub.2. Other conditions, such
as LHSV, hydrogen/feed ratio, were similar to those used in the
previous process under 6996 kPa (1000 psig) H.sub.2. The
temperature of Reactor 1 (containing Crosfield 599) and Reactor 2
(containing Pt/ZSM-48) was kept same. The dewaxed oil yields and
properties are summarized in Table 7.
7TABLE 7 Lube Yield and Properties for Dewaxing the MNFO under 400
psig H.sub.2 343.degree. C.+ Pour Cloud Temp Yield, KV@100.degree.
C. Point Point S N Tot. Arom (.degree. C.) wt % Feed (cSt) VI
(.degree. C.) (.degree. C.) (ppm) (ppm) (mmol/Kg) 354 77.6 5.429
142.0 24 36 -- -- -- 360 73.6 5.557 136.4 18 24 -- -- -- 363 71.3
5.442 132.2 12 21 -- -- -- 366 67.7 5.513 129.2 9 18 -- -- -- 368
62.0 5.372 125.0 -3 8 49 <5 402 371 57.4 5.916 119.3 -6 2 48
<5 425 374 54.5 5.409 116.3 -24 -5 37 <5 478 377 50.8 5.933
111.1 -33 -17 -- -- -- 379 45.7 5.316 108.4 <-54 -51 -- --
--
[0061] The above results demonstrate that the cascaded dual
catalysts system remains effective for dewaxing Foots oil at
hydrogen pressure as low as 2859 kPa 400 psig). Low pressure
process has significant advantages versus high pressure operation
because of the simplicity and low cost in design and construction
of low pressure reactors. By comparing to the dewaxing data
obtained at 6996 kPa (1000 psig) H.sub.2, the hydrogen pressure
effects on catalysts activity was found to be minimal for this
particular feed with high contents of sulfur and nitrogen. Upon
decreasing H.sub.2 pressure, the lube yield is slightly higher at
conventional pour point with essentially no change in lube VI. At a
low hydrogen pressure, the effectiveness of the pre-hydrotreating
catalyst (Crosfield 599) decreases; as the result, both sulfur and
aromatic contents in the lube products increase (see Tables 6 and
7).
Example 7
[0062] This example shows the dewaxing of LNFO at 6996 kPa H.sub.2.
The process conditions used for dewaxing the LNFO were similar to
those for the MNFO. The experiments were carried out under 6996 kPa
(1000 psig) H.sub.2 at 2.0 h.sup.-1 LHSV based on Crosfield 599 and
1.0 h.sup.-1 LHSV based on Pt/ZSM-48. Hydrogen/feed ratio of 5700
scf/bbl (1015 m.sup.3/m.sup.3) was employed. The temperature of
Reactor 1 (containing Crosfield 599) and Reactor 2 (containing
Pt/ZSM-48) was kept same. The dewaxed oil yields and properties are
summarized in Table 8; and for further clarification, the results
are depicted in FIGS. 5-8.
8TABLE 8 Lube Yield and Properties for Dewaxing the LNFO under 1000
psig H.sub.2 343.degree. C.+ DOS Temp Yield, KV@100.degree. C. Pour
Point Cloud Point S (days) (.degree. F.) wt % Feed (cSt) VI
(.degree. C.) (.degree. C.) (ppm) 27 650 82.0 3.280 141.0 24 27
<25 28 660 78.0 3.435 140.0 21 23 -- 30 675 67.6 3.458 132.5 9
19 <25 31 680 61.2 3.530 128.6 3 7 <25 32 685 57.2 3.464
123.1 -9 -1 <25 34 695 46.6 4.122 120.9 -33 -10 <25 42 670
66.6 3.193 130.6 0 5 <25
[0063] These results demonstrate that the cascaded dual catalysts
system is also effective and selective in converting the light
neutral Foots oil to high VI (>120), low sulfur (<25 ppm)
Group III lube base stocks. Lube yield of about 57% was obtained at
conventional pour point.
[0064] In addition, the data in Table 8 show that after 10 days on
stream upon switching feed from the MNFO to the LNFO, the catalyst
activity increases by approximately 10.degree. F., along with small
lube yield (+5%) and VI (+2) increase.
Example 8
[0065] Byproduct Yields for Dewaxing the MNFO and LNFO were
determined as follows. The processes were carried out under 6996
kPa (1000 psig) H.sub.2 at 2.0 h.sup.-1 LHSV based on Crosfield 599
and 1.0 h.sup.-1 LHSV based on Pt/ZSM-48. Hydrogen/feed ratio of
1015 m.sup.3/m.sup.3 (5700 scf/bbl was employed. The temperature of
Reactor 1 (containing Crosfield 599) and Reactor 2 (containing
Pt/ZSM-48) was kept same. The yields of dewaxed oil and lighter
byproducts are summarized in Table 9. For both MNFO and LNFO
dewaxing, the major byproducts were distillate and naphtha with
relatively small amount (<8%) of C.sub.1-C.sub.4 gases.
9TABLE 9 Byproduct Yields (wt % Feed) for Dewaxing the MNFO and
LNFO Process 343.degree. C..sup.F+ 166-343.degree. C.
C.sub.5-166.degree. C. Temp Lube PP 343.degree. C.+ Distillate
Naphtha C.sub.1-C.sub.4 Feed (.degree. C.) (.degree. C.) Lube Yield
Yield Yield Offgas Yield MNFO 368 -3 60.0 19.1 17.9 5.1 LNFO 363 -9
57.2 21.8 13.9 6.2 LNFO 368 -33 46.6 26.1 23.2 7.7
* * * * *