I discovered a recent ExxonMobil patent application on CATALYTIC DEWAXING OF
HYDROCARBON FEEDSTOCKS, thanks to one of the Google® Scholar alerts I have set
up to follow various topics [see the post
on setting up Google
Alerts].
The Google® Scholar alert highlighted the patent application identified by a
service known as freepatentsonline (http://www.freepatentsonline.com/).
Although the service offers free access to the full patent application, I
wanted to find the application on the originating source, i.e., the U.S. Patent
& Trademark Office (USPTO) (https://www.uspto.gov/)
I could not find this particular patent application on the USPTO site using the
Application Number: 16/709205, which is shown in the patent application shown below.
What’s up with that?
What’s up with that is that I made the mistake of using the full Application
Number: 16/709205
When I performed the same search by deleting 16/, i.e., using only 709205, I
found a list of seven applications, one of which was the one I was trying to
find.
TIP:
When a Google® search results in a patent application of interest, the quickest
way to search for it on the USPTO database is to do an Application Number
search using the number listed as United States Patent Application, i.e. the
Document Number, (e.g., 20200199468) rather than the number listed as the
actual Application Number (e.g., 16/709205)
So, for example, when I performed an Application Number search using the
Document Number 20200199468, I got only one result … which was the exact result
I was trying to find.
Both numbers are listed in the text of the freepatents ExxonMobil patent
application.
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CATALYTIC DEWAXING OF HYDROCARBON FEEDSTOCKS
United
States Patent Application 20200199468
Abstract:
In a process for improving the cold flow properties of a hydrocarbon feedstock,
the feedstock is contacted with a catalyst composition comprising an EMM-17
molecular sieve and a hydrogenation component under dewaxing conditions
effective to produce a dewaxed product having a cloud point and/or pour point
that is reduced relative to the cloud point and/or pour point of the feedstock
by at least 5° C.
Inventors:
Gatt, Joseph E. (Annandale, NJ, US), Lonergan, William W. (Humble, TX, US), Weigel,
Scott J. (Allentown, PA, US), Johnson, Ivy D. (Lawrenceville, NJ, US), Strohmaier,
Karl G. (Port Murray, NJ, US), Weston, Simon C. (Annandale, NJ, US)
Application Number: 16/709205
Publication Date: 06/25/2020
Filing Date: 12/10/2019
Assignee: ExxonMobil Research and Engineering Company (Annandale, NJ, US)
International Classes: C10G73/34; C10G45/64
Claims:
1. A process for improving the cold flow properties of a hydrocarbon feedstock,
the process comprising: contacting the feedstock with a catalyst composition
comprising an EMM-17 molecular sieve and a hydrogenation component under
dewaxing conditions effective to produce a dewaxed product having a cloud point
and/or pour point that is reduced relative to the cloud point and/or pour point
of the feedstock by at least 5° C.
2. The process of claim 1, wherein the hydrocarbon feedstock comprises a
distillate fraction having an initial boiling point of at least 95° C. and a
final boiling point 455° C. or less.
3. The process of claim 1, wherein the hydrocarbon feedstock comprises a
lubricant basestock having an initial boiling point of at least 220° C. and a
final boiling point up to 650° C.
4. The process of claim 1, wherein the hydrocarbon feedstock comprises no more
than 10 ppm by weight of nitrogen and/or sulfur.
5. The process of claim 1, wherein the hydrocarbon feedstock comprises up to
2.0 wt. % sulfur and up to 500 ppm by weight nitrogen.
6. The process of claim 1, wherein the dewaxing conditions comprise a
temperature of from 200 to 450° C., a hydrogen partial pressure of from 1.4
MPag to 34.6 MPag (200 psig to 5000 psig), and a hydrogen treat gas to feed
rate of from 35.6 m3/m3 (200 SCF/B) to 1781 m3/m3 (10,000 scf/B).
7. The process of claim 1, wherein the dewaxing conditions comprise a temperature
of from 270 to 400° C., a hydrogen partial pressure of from 4.8 MPag to 20.7
MPag, and a hydrogen treat gas to feed rate of from 178 m3/m3 (1000 SCF/B) to
890.6 m3/m3 (5000 SCF/B).
8. The process of claim 1, wherein the EMM-17 molecular sieve comprises an
aluminosilicate.
9. The process of claim 8 wherein the molecular sieve has a silica to alumina
molar ratio of at least 50.
10. The process of claim 8, wherein the catalyst is steamed prior to the
contacting to reduce the framework aluminum content of the molecular sieve.
11. The process of claim 1, wherein the hydrogenation component comprises at
least one metal or compound thereof from Groups 6 to 12 of the Periodic Table
of the Elements.
12. The process of claim 1, wherein the metal hydrogenation component comprises
Pt, Pd, or a combination thereof.
13. The process of claim 1, wherein the dewaxing catalyst comprises from 5 to
80 wt. % of the hydrogenation component.
14. The process of claim 1, wherein the dewaxing catalyst further comprises at
least 5% by weight of a binder.
15. A process for improving the cold flow properties of a hydrocarbon
feedstock, the process comprising: (a) contacting the feedstock with a first
hydrotreating catalyst composition under conditions effective to reduce at
least one of the sulfur, nitrogen or aromatic content of the feedstock and
produced a hydrotreated product; and (b) contacting the hydrotreated product
with a second catalyst composition different from the first catalyst
composition and comprising an EMM-17 molecular sieve and a hydrogenation
component under dewaxing conditions effective to produce a dewaxed product
having a cloud point and/or pour point that is reduced relative to the cloud
point and/or pour point of the feedstock by at least 5° C.
16. The process of claim 15, wherein the first hydrotreating catalyst
composition comprises a metal or compound thereof from Groups 6 and 8 to 10 of
the Periodic Table on a refractory metal oxide support.
17. The process of claim 15, wherein the contacting steps (a) and (b) are
conducted in a single reactor.
18. The process of claim 15, wherein the contacting steps (a) and (b) are
conducted in separate reactors.
Description:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application No. 62/783,433
filed Dec. 21, 2018, which is herein incorporated by reference in its entirety.
FIELD
This disclosure relates to catalytic dewaxing of hydrocarbon feedstocks.
BACKGROUND
Most lubricating oil feedstocks must be dewaxed in order to manufacture
finished products which will remain fluid down to the lowest temperature of
use. Dewaxing is the process of separating or converting hydrocarbons which
solidify readily (e.g., waxes) in petroleum fractions. Processes for dewaxing
petroleum distillates have been known for a long time. As used herein, dewaxing
means a reduction in a least some of the normal paraffin content of the feed.
The reduction may be accomplished by isomerization of n-paraffins or naphthenic
molecules and/or cracking, or hydrocracking.
Dewaxing is required when highly paraffinic oils are to be used in products
which need to flow at low temperatures, i.e., lubricating oils, heating oil,
diesel fuel, and jet fuel. These oils contain high molecular weight straight
chain and slightly branched paraffins which cause the oils to have high pour
points and cloud points and, for jet fuels, high freeze points. In order to
obtain adequately low pour points, these waxes must be wholly or partly removed
or converted. In the past, various solvent removal techniques were used, such
as MEK (methyl ethyl ketone-toluene solvent) dewaxing, which utilizes solvent
dilution, followed by chilling to crystallize the wax, and filtration.
The decrease in demand for petroleum waxes as such, together with the increased
demand for gasoline and distillate fuels, has made it desirable to find
processes which not only remove the waxy components but which also convert
these components into other materials of higher value. Catalytic dewaxing
processes achieve this end by either of two methods or a combination thereof.
The first method requires the selective cracking of the longer chain
n-paraffins, to produce lower molecular weight products which may be removed by
distillation. Processes of this kind are described, for example, in The Oil and
Gas Journal, Jan. 6, 1975, pages 69 to 73 and U.S. Pat. No. 3,668,113. The
second method requires the isomerization of straight chain paraffins and
substantially straight chain paraffins with minimal branching to more branched species.
Processes of this kind are described in U.S. Pat. Nos. 4,419,220 and 4,501,926.
To date, there have been a number of methods developed for dewaxing hydrocarbon
feeds. Many dewaxing processes that are presently being used reduce the pour
and cloud point of a hydrocarbon stream to acceptable levels at the price of
producing more than a desirable amount of naphtha and light gas. An ideal
economic fuel dewaxing process would reduce the cloud point or pour point of
the feed to acceptable levels while maximizing the yields of diesel fuel and
heating oil and minimizing the yields of naphtha and light gas. Previous
dewaxing processes have utilized zeolite hydrodewaxing catalysts including
ZSM-5, ZSM-11, ZSM-12, ZSM-20, ZSM-22, ZSM-23, ZSM-34, ZSM-35, ZSM-38, ZSM-48,
ZSM-50, mordenite, SAPO-11, and zeolite beta.
In order to obtain the desired selectivity, many previously known processes
have used a zeolite catalyst having a pore size which admits the straight chain
n-paraffins, either alone or with only slightly branched chain paraffins, but
which excludes more highly branched materials, cycloaliphatics and aromatics.
Zeolites such as ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35 and ZSM-38 have been
proposed for this purpose in dewaxing processes and their use is described in
U.S. Pat. Nos. 3,894,938; 4,176,050; 4,181,598; 4,222,855; 4,229,282; and
4,247,388. A dewaxing process employing synthetic offretite is described in
U.S. Pat. No. 4,259,174. A hydrocracking process employing zeolite beta as the
acidic component is described in U.S. Pat. No. 3,923,641.
A new generation of dewaxing catalysts needs to be developed which improve upon
both the dewaxing activity and selectivity of the currently available
technology and which are effective over a broad range of applications and
feedstocks, including both sweet and sour feeds.
SUMMARY
According to the present disclosure, it has now been found that the recently
discovered molecular sieve material, known as EMM-17, exhibits unusually high
activity and selectivity for the catalytic dewaxing of hydrocarbon feeds
including naphtha, distillate, VGO, and lubes.
Thus, in one aspect, the present disclosure relates to a process for improving
the cold flow properties of a hydrocarbon feedstock, the process comprising:
contacting the feedstock with a catalyst composition comprising an EMM-17
molecular sieve and a hydrogenation component under dewaxing conditions
effective to produce a dewaxed product having a cloud point and/or pour point
that is reduced relative to the cloud point and/or pour point of the feedstock
by at least 5° C.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a line graph of n-decane conversion against temperature for the
EMM-17 and known dewaxing catalysts employed in Example 3.
FIG. 2 is a line graph of n-decane conversion against iso-decane yield for the
EMM-17 and known dewaxing catalysts employed in Example 3.
FIG. 3 is a bar graph comparing the decrease in cloud point and the distillate
yield loss for the EMM-17 and ZSM-48 catalysts in the hydroisomerization of the
distillate feed in Example 4.
FIG. 4 is a graph plotting the decrease in cloud point (delta cloud) against
dewaxing temperature for the various catalysts employed in the dewaxing test of
Example 5.
FIG. 5 is a graph plotting distillate yield loss against delta cloud for the
various catalysts employed in the dewaxing test of Example 5.
FIG. 6 is a graph of product pour point against dewaxing temperature for the
various catalysts employed in the dewaxing test of Example 6.
FIG. 7 is a graph of product pour point against 700° F.+(371° C.+) conversion
for the various catalysts employed in the dewaxing test of Example 6.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Described herein is a process for improving the cold flow properties of a
hydrocarbon feedstock. The process comprises contacting the feedstock with a
catalyst composition comprising an EMM-17 molecular sieve and a hydrogenation
component under dewaxing conditions, such as those effective to hydroisomerize
n-alkanes in the feedstock, to produce a dewaxed product having a cloud point
and/or pour point that is reduced relative to the cloud point and/or pour point
of the feedstock by at least 5° C. All cloud point values referred to herein
are as measured in accordance with ASTM D5773 and all pour point values are as
measured in accordance with ASTM D5949.
It is found that dewaxing catalysts containing EMM-17 exhibit significantly
higher activity with comparable selectivity to current state of the art
dewaxing catalysts across a broad range of conditions and applications. For
distillate applications, this activity benefit can be seen in sweet
applications (<10 1.5="" 30="" 500="" 60="" a="" ability="" achieve="" activity="" additional="" allow="" allowing="" allows="" also="" and="" application="" applications.="" applications="" are="" art="" as="" at="" based="" basis="" be="" benefit="" benefits="" both="" br="" by="" can="" catalyst="" catalysts.="" catalysts="" cloud="" clouds="" commercial="" commercially="" comparable="" compared="" comparison="" comparisons="" containing="" content.="" content="" conventional="" crude="" current="" deep="" delta="" dewax="" dewaxing.="" dewaxing="" displaced="" distillate="" drop-in="" emm-17="" enable="" endpoints="" equivalent="" exhibit="" exhibits="" existing="" f.="" feeds="" flexibility="" for="" have="" head="" higher="" hydrotreater="" hydrotreaters="" hydrotreating="" impact="" improvements.="" in="" isomerization="" it="" itself="" larger="" leading="" load="" loads="" loss="" lower="" manifest="" many="" minimal="" more="" n.="" n="" near="" need="" of="" operating="" or="" point="" ppm="" process="" processed.="" provide="" reasonable="" relative="" results="" run="" s="" selectivity.="" selectivity="" service="" significant="" since="" sizes="" slightly="" solutions="" sour="" space="" start="" state="" successful="" target="" temperatures="" than="" that="" the="" this="" to="" trim="" units="" up="" velocities="" waxier="" when="" where="" window="" with="" would="" wt.="" yield="">
Catalyst Composition
The catalyst composition employed in the present process comprises, as an
active component, the molecular sieve EMM-17. In its calcined form, EMM-17 is
characterized by an X-ray diffraction pattern which includes at least the peaks
shown below in Table 1 and in its as-synthesized form, by an X-ray diffraction
pattern which includes at least the peaks shown below in Table 2.
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