U.S. patent application number 16/572946 was filed with the patent office on 2020-01-09 for lubricant basestock production with enhanced aromatic saturation.
The applicant listed for this patent is ExxonMobil Research and Engineering Company. Invention is credited to Ajit B. Dandekar, Bradley R. Fingland, Kendall S. Fruchey, Scott J. Weigel.
Application Number | 20200010772 16/572946 |
Document ID | / |
Family ID | 59959184 |
Filed Date | 2020-01-09 |
![](/patent/app/20200010772/US20200010772A1-20200109-D00000.png)
![](/patent/app/20200010772/US20200010772A1-20200109-D00001.png)
![](/patent/app/20200010772/US20200010772A1-20200109-D00002.png)
![](/patent/app/20200010772/US20200010772A1-20200109-D00003.png)
![](/patent/app/20200010772/US20200010772A1-20200109-D00004.png)
![](/patent/app/20200010772/US20200010772A1-20200109-D00005.png)
![](/patent/app/20200010772/US20200010772A1-20200109-D00006.png)
United States Patent
Application |
20200010772 |
Kind Code |
A1 |
Dandekar; Ajit B. ; et
al. |
January 9, 2020 |
LUBRICANT BASESTOCK PRODUCTION WITH ENHANCED AROMATIC
SATURATION
Abstract
Systems and methods are provided for producing lubricant
basestocks having a reduced or minimized aromatics content. A first
processing stage can perform an initial amount of hydrotreating
and/or hydrocracking. A first separation stage can then be used to
remove fuels boiling range (and lower boiling range) compounds. The
remaining lubricant boiling range fraction can then be exposed
under hydrocracking conditions to a USY catalyst including a
supported noble metal, such as Pt and/or Pd. The USY catalyst can
have a desirable combination of catalyst properties, such as a unit
cell size of 24.30 or less (or 24.24 or less), a silica to alumina
ratio of at least 50 (or at least 80), and an alpha value of 20 or
less (or 10 or less). In some aspects, the effluent from the second
(hydrocracking) stage can be dewaxed without further separation. In
such aspects, a portion of the dewaxed effluent can be used as a
recycle quench stream to cool the hydrocracking effluent prior to
entering the dewaxing reactor.
Inventors: |
Dandekar; Ajit B.; (Spring,
TX) ; Fingland; Bradley R.; (Mason, MI) ;
Fruchey; Kendall S.; (Humble, TX) ; Weigel; Scott
J.; (Allentown, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ExxonMobil Research and Engineering Company |
Annandale |
NJ |
US |
|
|
Family ID: |
59959184 |
Appl. No.: |
16/572946 |
Filed: |
September 17, 2019 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15468406 |
Mar 24, 2017 |
10457877 |
|
|
16572946 |
|
|
|
|
62356749 |
Jun 30, 2016 |
|
|
|
62315808 |
Mar 31, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2020/02 20130101;
C10G 2300/202 20130101; C10G 69/02 20130101; C10N 2020/065
20200501; C10N 2030/10 20130101; C10M 2203/1006 20130101; C10G
65/12 20130101; C10M 2203/1065 20130101; C10N 2040/12 20130101;
C10N 2030/02 20130101; C10G 2400/10 20130101; C10M 2203/1045
20130101; C10N 2040/25 20130101; C10N 2020/01 20200501; C10G
2300/302 20130101; C10M 2203/1025 20130101; C10M 101/02 20130101;
C10N 2030/08 20130101; C10G 47/18 20130101 |
International
Class: |
C10M 101/02 20060101
C10M101/02; C10G 47/18 20060101 C10G047/18; C10G 65/12 20060101
C10G065/12; C10G 69/02 20060101 C10G069/02 |
Claims
1.-13. (canceled)
14. A system for producing a lubricant boiling range product,
comprising: a hydrotreating reactor comprising a hydrotreating feed
inlet, a hydrotreating effluent outlet, and at least one fixed
catalyst bed comprising a hydrotreating catalyst; a separation
stage having a first separation stage inlet and a second separation
stage inlet, the first separation stage inlet being in fluid
communication with the hydrotreating effluent outlet, the
separation stage further comprising a plurality of separation stage
liquid effluent outlets, one or more of the separation stage liquid
effluent outlets corresponding to product outlets; a hydrocracking
reactor comprising a hydrocracking feed inlet, a hydrocracking
effluent outlet, and at least one fixed catalyst bed comprising a
hydrocracking catalyst, the hydrocracking feed inlet being in fluid
communication with at least one separation stage liquid effluent
outlet, and the hydrocracking catalyst comprising USY zeolite
having a unit cell size of 24.30 .ANG. or less, a silica to alumina
ratio of at least 50, and an Alpha value of 20 or less, the
hydrocracking catalyst further comprising 0.1 wt % to 5.0 wt % of a
Group 8-10 noble metal supported on the hydrocracking catalyst; and
a dewaxing reactor comprising a dewaxing feed inlet, a dewaxing
effluent outlet, and at least one fixed catalyst bed comprising a
dewaxing catalyst, the dewaxing feed inlet being in fluid
communication with the hydrocracking effluent outlet and being in
fluid communication with the dewaxing effluent outlet.
15. The system of claim 14, wherein the dewaxing reactor further
comprises a fixed bed comprising a hydrofinishing catalyst, wherein
the hydrotreating reactor further comprises a fixed bed comprising
a hydrocracking catalyst, or a combination thereof.
16. The system of claim 14, further comprising a hydrofinishing
reactor comprising a hydrofinishing feed inlet, a hydrofinishing
effluent outlet, and at least one fixed catalyst bed comprising a
hydrofinishing catalyst, the hydrofinishing feed inlet being in
direct fluid communication with the dewaxing feed outlet, the
dewaxing feed inlet being in direct fluid communication with the
hydrofinishing effluent outlet and in indirect fluid communication
with the dewaxing effluent outlet.
17. The system of claim 14, the system further comprising an
additional hydrocracking reactor comprising an additional
hydrocracking feed inlet, an additional hydrocracking effluent
outlet, and at least one fixed catalyst bed comprising an
additional hydrocracking catalyst, the additional hydrocracking
reactor providing indirect fluid communication between the
hydrotreating effluent outlet and the first separation stage inlet,
the additional hydrocracking feed inlet being in fluid
communication with the hydrotreating effluent outlet, the
additional hydrocracking effluent outlet being in fluid
communication with the first separation stage inlet.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 62/315,808 filed Mar. 31, 2016 and U.S.
Provisional Application Ser. No. 62/356,749 filed Jun. 30, 2016,
which are both herein incorporated by reference in their
entirety.
FIELD
[0002] Systems and methods are provided for production of lubricant
boiling range products.
BACKGROUND
[0003] Many refineries include thermal cracking processes as part
of an overall process flow for handling challenged feeds. Thermal
cracking processes have traditionally been effective for producing
naphtha fractions suitable for use in motor gasoline products, but
effective production of high quality distillate fuel products has
remained a challenge.
[0004] U.S. Patent Application Publication 2011/0315596 describes
an integrated process for hydrocracking and dewaxing of
hydrocarbons to form naphtha, diesel, and/or lubricant base stock
boiling range products. The integrated process includes dewaxing
and optionally hydrocracking under sour conditions, a separation to
form a first diesel product and a bottoms product, and additional
hydrocracking and dewaxing to form a second diesel product and
optionally a lubricant base oil product. The hydrocracking and
dewaxing catalysts can include base metals or can include Pd and/or
Pt. An example of a hydrocracking catalyst is USY and an example of
a dewaxing catalyst is ZSM-48.
[0005] U.S. Pat. No. 8,932,454 describes a method of making and
using a Y zeolite hydrocracking catalyst. The Y zeolite catalyst
has a small mesoporous peak in the pore size distribution of around
40 .ANG. as measured by nitrogen desorption.
[0006] U.S. Pat. No. 8,778,171 describes a method of making and
using a Y zeolite hydrocracking catalyst. The Y zeolite catalyst
contains stabilized aggregates of Y zeolite primary crystallites
having a size of 0.5 microns or less.
[0007] U.S. Patent Application Publication 2013/0341243 describes a
hydrocracking process selective for improved distillate and
improved lube yield and properties. A two-stage hydrocracking
catalyst can be used for hydrocracking of a feed to form a
converted portion suitable for diesel fuel production and an
unconverted portion suitable for production of lubricant base
stocks. The two-stage hydrocracking catalyst can correspond to a
first stage catalyst including Pd and/or Pt supported on USY and a
second stage catalyst including Pd and/or Pt supported on
ZSM-48.
SUMMARY
[0008] In an aspect, a method for producing a lubricant boiling
range product is provided. The method can include hydroprocessing a
feedstock comprising a 650.degree. F. (.about.343.degree. C.)
portion under first hydroprocessing conditions to form a
hydroprocessed effluent. At least a portion of the hydroprocessed
effluent can be fractionated to form at least a first fuels boiling
range fraction and a second fraction, the second fraction
comprising a lubricant boiling range portion. The second fraction
can be hydrocracked in the presence of hydrocracking catalyst under
hydrocracking conditions to form a hydrocracked effluent.
Optionally, the hydrocracking catalyst can comprise USY zeolite
having a unit cell size of 24.30 .ANG. or less and/or a silica to
alumina ratio of at least 50 and/or an Alpha value of 20 or less.
Optionally, the hydrocracking catalyst can further comprise 0.1 wt
% to 5.0 wt % of a Group 8-10 noble metal supported on the
hydrocracking catalyst. The hydrocracking conditions can include a
hydrocracking reactor exit temperature. At least a portion of the
hydrocracked effluent and a recycled portion of a dewaxed effluent
can be dewaxed under catalytic dewaxing conditions to form a
dewaxed effluent. The recycled portion of the dewaxed effluent can
optionally comprise 20 wt % to 50 wt % of the dewaxed effluent. The
catalytic dewaxing conditions can comprise a dewaxing reactor inlet
temperature that is at least 20.degree. C. lower than the
hydrocracking reactor exit temperature. At least a portion of the
dewaxed effluent can be separated to form at least the recycled
portion of the dewaxed effluent and a product portion of the
dewaxed effluent. The product portion of the dewaxed effluent can
be fractionated to form at least a fuels boiling range product and
a lubricant boiling range product, wherein the lubricant boiling
range product optionally has an aromatics content of 2.0 wt % or
less.
[0009] In an aspect, a system for producing a lubricant boiling
range product is provided. The system can include a hydrotreating
reactor comprising a hydrotreating feed inlet, a hydrotreating
effluent outlet, and at least one fixed catalyst bed comprising a
hydrotreating catalyst. The system can further include a separation
stage having a first separation stage inlet and a second separation
stage inlet, the first separation stage inlet being in fluid
communication with the hydrotreating effluent outlet. The
separation stage can further comprise a plurality of separation
stage liquid effluent outlets, with one or more of the separation
stage liquid effluent outlets optionally corresponding to product
outlets. The system can further include a hydrocracking reactor
comprising a hydrocracking feed inlet, a hydrocracking effluent
outlet, and at least one fixed catalyst bed comprising a
hydrocracking catalyst. The hydrocracking feed inlet can be in
fluid communication with at least one separation stage liquid
effluent outlet. The hydrocracking catalyst can comprise USY
zeolite having a unit cell size of 24.30 .ANG. or less and/or a
silica to alumina ratio of at least 50 and/or an Alpha value of 20
or less. The hydrocracking catalyst can further comprise 0.1 wt %
to 5.0 wt % of a Group 8-10 noble metal supported on the
hydrocracking catalyst. The system can further include a dewaxing
reactor comprising a dewaxing feed inlet, a dewaxing effluent
outlet, and at least one fixed catalyst bed comprising a dewaxing
catalyst. The dewaxing feed inlet can be in fluid communication
with the hydrocracking effluent outlet and/or can be in fluid
communication with the dewaxing effluent outlet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 schematically shows an example of a configuration
suitable for processing a feedstock to form at least a lubricant
boiling range fraction.
[0011] FIG. 2 schematically shows another example of a
configuration suitable for processing a feedstock to form at least
a lubricant boiling range fraction.
[0012] FIG. 3 schematically shows another example of a
configuration suitable for processing a feedstock to form at least
a lubricant boiling range fraction.
[0013] FIG. 4 shows the composition of exemplary low viscosity base
stocks of this disclosure compared with the composition of
reference low viscosity base stocks.
[0014] FIG. 5 shows the composition of exemplary high viscosity
base stocks of this disclosure compared with the composition of
reference high viscosity base stocks.
[0015] FIG. 6 shows aromatic saturation relative to 700.degree. F.
(.about.371.degree. C.) conversion for hydrocracking under sour
conditions and under sweet conditions.
DETAILED DESCRIPTION
Overview
[0016] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
[0017] In various aspects, systems and methods are provided for
producing lubricant basestocks having a reduced or minimized
aromatics content. A first processing stage can perform an initial
amount of hydrotreating and/or hydrocracking. A first separation
stage can then be used to remove fuels boiling range (and lower
boiling range) compounds. The remaining lubricant boiling range
fraction can then be exposed under hydrocracking conditions to a
USY catalyst including a supported noble metal, such as Pt and/or
Pd. The USY catalyst can have a desirable combination of catalyst
properties, such as a unit cell size of 24.30 or less (or 24.24 or
less), a silica to alumina ratio of at least 50 (or at least 80),
and an alpha value of 20 or less (or 10 or less). In some aspects,
the effluent from the second (hydrocracking) stage can be dewaxed
without further separation. In such aspects, a portion of the
dewaxed effluent can be used as a recycle quench stream to cool the
hydrocracking effluent prior to entering the dewaxing reactor. The
combination of hydrocracking in the presence of the USY catalyst
and using a quench stream prior to the dewaxing reactor can allow
for production of lubricant boiling range products having a reduced
or minimized content of aromatics, such as 1.5 wt % or less, or 1.0
wt % or less.
[0018] In various aspects, use of a recycle quench stream can allow
the effluent from a USY hydrocracking reactor to be passed into a
dewaxing reactor without intermediate separation while also
allowing for greater relative control of various temperatures. For
example, the temperature of the hydrocracked effluent at the inlet
to the dewaxing reactor can be at least 10.degree. F.
(.about.5.degree. C.) cooler than the temperature of the input feed
to the USY hydrocracking reactor, or at least 20.degree. F.
(.about.10.degree. C.) cooler, such as up to 40.degree. F.
(.about.20.degree. C.) cooler or more. Additionally or alternately,
the temperature of the hydrocracked effluent at the inlet to the
dewaxing reactor can be at least 40.degree. F. (.about.20.degree.
C.) cooler than the temperature of the hydrocracked effluent at the
exit from the USY hydrocracking reactor, or at least 50.degree. F.
(.about.25.degree. C.), or at least 60.degree. F.
(.about.30.degree. C.), such as up to 80.degree. F.
(.about.40.degree. C.) or more. In order to cool the hydrocracked
effluent, 20 wt % to 50 wt % of the dewaxed effluent can be
recycled to a location prior to the inlet to the dewaxing reactor.
The location for withdrawing the dewaxed effluent for recycle can
be any convenient location after the dewaxing reactor and prior to
fractionation of the dewaxed effluent. For example, if the dewaxing
reactor includes a hydrofinishing catalyst and/or if the dewaxed
effluent is passed into a separate hydrofinishing reactor prior to
fractionation, the dewaxed effluent used for the recycle stream can
correspond to a recycled portion of a dewaxed and hydrofinished
effluent. In some aspects, the weight average bed temperature of
the dewaxing reactor can be greater than the dewaxing reactor inlet
temperature by 15.degree. C. or less, or by 10.degree. C. or
less.
[0019] FIG. 1 shows an example of a general processing
configuration suitable for processing a feedstock to produce
distillate fuels. In FIG. 1, a feedstock 105 can be introduced into
a first reactor 110. A reactor such as first reactor 110 can
include a feed inlet and an effluent outlet. First reactor 110 can
correspond to a hydrotreating reactor, a hydrocracking reactor, or
a combination thereof. Optionally, a plurality of reactors can be
used to allow for selection of different conditions. For example,
if both a first reactor 110 and optional second reactor 120 are
included in the reaction system, first reactor 110 can correspond
to a hydrotreatment reactor while second reactor 120 can correspond
to a hydrocracking reactor. Yet other options for arranging
reactor(s) and/or catalysts within the reactor(s) to perform
initial hydrotreating and/or hydrocracking of a feedstock can also
be used. Optionally, if a configuration includes multiple reactors
in the initial stage, a gas-liquid separation can be performed
between reactors to allow for removal of light ends and contaminant
gases. In aspects where the initial stage includes a hydrocracking
reactor, the hydrocracking reactor in the initial stage can be
referred to as an additional hydrocracking reactor.
[0020] The hydroprocessed effluent 125 from the final reactor (such
as reactor 120) of the initial stage can then be passed into a
fractionator 130, or another type of separation stage. Fractionator
130 (or other separation stage) can separate the hydroprocessed
effluent to form one or more fuel boiling range fractions 137, a
light ends fraction 132, and a lubricant boiling range fraction
135. The lubricant boiling range fraction 135 can often correspond
to a bottoms fraction from the fractionator 130. The lubricant
boiling range fraction 135 can undergo further hydrocracking in the
presence of a USY zeolite in second stage reactor 140. In the
configuration shown in FIG. 1, the effluent 145 from second stage
reactor 140 can be fractionated 150 to separate out light ends 152
and/or fuel boiling range fraction(s) 157 prior to further
processing of lubricant boiling range fraction 155, such as further
dewaxing and/or hydrofinishing.
[0021] The configuration in FIG. 1 can allow the second stage
reactor 140 to be operated under sweet processing conditions,
corresponding to the equivalent of a feed (to the second stage)
sulfur content of 100 wppm or less. Under such "sweet" processing
conditions, the configuration in FIG. 1, in combination with use of
the USY catalyst, can allow for production of a hydrocracked
effluent having a reduced or minimized content of aromatics.
[0022] In the configuration shown in FIG. 1, the final reactor in
(such as reactor 120) in the initial stage can be referred to as
being in direct fluid communication with an inlet to the
fractionator 130 (or an inlet to another type of separation stage).
The other reactors in the initial stage can be referred to as being
in indirect fluid communication with the inlet to the separation
stage, based on the indirect fluid communication provided by the
final reactor in the initial stage. The reactors in the initial
stage can generally be referred to as being in fluid communication
with the separation stage, based on either direct fluid
communication or indirect fluid communication.
[0023] Because second stage reactor 140 is operating under sweet
operating conditions, it can be beneficial to avoid having a
separation stage 150 between second stage reactor 140 and a
subsequent reactor containing a dewaxing catalyst. FIG. 2 shows an
example of a reaction configuration where separation stage 250 is
located after additional dewaxing and/or hydrofinishing reactor
260. The configuration in FIG. 2 can be suitable for production of
lubricant base stocks with unexpected compositional properties, as
described in Example 1 below.
[0024] In some limited situations, one potential difficulty with
passing the effluent 245 into additional reactor 260 without an
additional separation is that the desired operating temperature for
dewaxing in additional reactor 260 can be substantially lower than
the exit temperature of reactor 140. One option for reducing the
temperature of effluent 245 can be to use make-up hydrogen or
another high pressure gas stream as a quench gas. However, due to
the limited heat capacity of a gas a quench gas can provide only a
limited amount of cooling for effluent 245. As a result, a
configuration similar to FIG. 2 can lead to effluent 245 being at a
temperature above the desired operating temperature for the
dewaxing reaction in additional reactor 260.
[0025] In various aspects, a configuration similar to FIG. 3 can be
used to allow for improved aromatic saturation during dewaxing
and/or hydrofinishing. A portion 343 of the dewaxed effluent 365
from additional reactor 260 can be recycled and used as a quench
fluid for effluent 245. This can allow for further reduction of the
temperature of effluent 145 prior to entering additional reactor
260, so that the input temperature of effluent 145 can match the
desired inlet temperature for additional reactor 260.
[0026] Use of liquid recycle can potentially provide a variety of
additional benefits. One benefit can be additional aromatic
saturation of the feed, as a portion 343 of the dewaxed effluent
365 passes through additional reactor 260 at least an additional
time. This can result in a lubricant boiling range fraction 355
with an unexpectedly low aromatics content. Additionally or
alternately, use of a portion 343 of dewaxed effluent 365 as a
liquid recycle stream for quenching can reduce or minimize the need
for high pressure quench gas, which can reduce processing
costs.
[0027] In this discussion, the naphtha boiling range is defined as
50.degree. F. (.about.10.degree. C., roughly corresponding to the
lowest boiling point of a pentane isomer) to 315.degree. F.
(157.degree. C.). The jet boiling range is defined as 315.degree.
F. (157.degree. C.) to 460.degree. F. (238.degree. C.). The diesel
boiling range is defined as 460.degree. F. (238.degree. C.) to
650.degree. F. (343.degree. C.). The distillate fuel boiling range
(jet plus diesel), is defined as 315.degree. F. (157.degree. C.) to
650.degree. F. (343.degree. C.). The fuels boiling range is defined
as .about.10.degree. C. to 343.degree. C. The lubricant boiling
range is defined as 650.degree. F. (343.degree. C.) to 1050.degree.
F. (566.degree. C.). Optionally, when forming a lubricant boiling
portion by fractionation after one or more stages of
hydroprocessing (e.g., hydrotreating, hydrocracking, catalytic
dewaxing, hydrofinishing), a lubricant boiling range portion can
optionally correspond to a bottoms fraction, so that higher boiling
range compounds may also be included in the lubricant boiling range
portion. Compounds (C.sub.4-) with a boiling point below the
naphtha boiling range can be referred to as light ends. It is noted
that due to practical consideration during fractionation (or other
boiling point based separation) of hydrocarbon-like fractions, a
fuel fraction formed according to the methods described herein may
have T5 and T95 distillation points corresponding to the above
values (or T10 and T90 distillation points), as opposed to having
initial/final boiling points corresponding to the above values.
[0028] In this discussion, unless otherwise specified, references
to a liquid effluent or a liquid product are references to an
effluent or product that is a liquid at 25.degree. C. and 100 kPa-a
(.about.1 atm).
[0029] In this discussion, conditions may be provided for various
types of hydroprocessing of feeds or effluents. Examples of
hydroprocessing can include, but are not limited to, one or more of
hydrotreating, hydrocracking, catalytic dewaxing, and
hydrofinishing/aromatic saturation. Such hydroprocessing conditions
can be controlled to have desired values for the conditions (e.g.,
temperature, pressure, LHSV, treat gas rate) by using at least one
controller, such as a plurality of controllers, to control one or
more of the hydroprocessing conditions. In some aspects, for a
given type of hydroprocessing, at least one controller can be
associated with each type of hydroprocessing condition. In some
aspects, one or more of the hydroprocessing conditions can be
controlled by an associated controller. Examples of structures that
can be controlled by a controller can include, but are not limited
to, valves that control a flow rate, a pressure, or a combination
thereof; heat exchangers and/or heaters that control a temperature;
and one or more flow meters and one or more associated valves that
control relative flow rates of at least two flows. Such controllers
can optionally include a controller feedback loop including at
least a processor, a detector for detecting a value of a control
variable (e.g., temperature, pressure, flow rate, and a processor
output for controlling the value of a manipulated variable (e.g.,
changing the position of a valve, increasing or decreasing the duty
cycle and/or temperature for a heater). Optionally, at least one
hydroprocessing condition for a given type of hydroprocessing may
not have an associated controller.
[0030] Group I basestocks or base oils are defined as base oils
with less than 90 wt % saturated molecules and/or at least 0.03 wt
% sulfur content. Group I basestocks also have a viscosity index
(VI) of at least 80 but less than 120. Group II basestocks or base
oils contain at least 90 wt % saturated molecules and less than
0.03 wt % sulfur. Group II basestocks also have a viscosity index
of at least 80 but less than 120. Group III basestocks or base oils
contain at least 90 wt % saturated molecules and less than 0.03 wt
% sulfur, with a viscosity index of at least 120. In addition to
the above formal definitions, some Group I basestocks may be
referred to as a Group I+basestock, which corresponds to a Group I
basestock with a VI value of 103 to 108. Some Group II basestocks
may be referred to as a Group II+basestock, which corresponds to a
Group II basestock with a VI of at least 113. Some Group III
basestocks may be referred to as a Group III+basestock, which
corresponds to a Group III basestock with a VI value of at least
140.
Feedstocks
[0031] A wide range of petroleum and chemical feedstocks can be
hydroprocessed in accordance with the invention. Suitable
feedstocks include whole and reduced petroleum crudes, atmospheric,
cycle oils, gas oils, including vacuum gas oils and coker gas oils,
light to heavy distillates including raw virgin distillates,
hydrocrackates, hydrotreated oils, slack waxes, Fischer-Tropsch
waxes, raffmates, and mixtures of these materials.
[0032] One way of defining a feedstock is based on the boiling
range of the feed. One option for defining a boiling range is to
use an initial boiling point for a feed and/or a final boiling
point for a feed. Another option is to characterize a feed based on
the amount of the feed that boils at one or more temperatures. For
example, a "T5" boiling point/distillation point for a feed is
defined as the temperature at which 5 wt % of the feed will boil
off. Similarly, a "T95" boiling point I distillation point is a
temperature at 95 wt % of the feed will boil. Boiling points,
including fractional weight boiling points, can be determined using
a suitable ASTM method, such as ASTM D2887.
[0033] Typical feeds include, for example, feeds with an initial
boiling point and/or a T5 boiling point and/or T10 boiling point of
at least 600.degree. F. (.about.316.degree. C.), or at least
650.degree. F. (.about.343.degree. C.), or at least 700.degree. F.
(371.degree. C.), or at least 750.degree. F. (.about.399.degree.
C.). Additionally or alternately, the final boiling point and/or
T95 boiling point and/or T90 boiling point of the feed can be
1100.degree. F. (.about.593.degree. C.) or less, or 1050.degree. F.
(.about.566.degree. C.) or less, or 1000.degree. F.
(.about.538.degree. C.) or less, or 950.degree. F.
(.about.510.degree. C.) or less. In particular, a feed can have a
T5 to T95 boiling range of 600.degree. F. (.about.316.degree. C.)
to 1100.degree. F. (.about.593.degree. C.), or a T5 to T95 boiling
range of 650.degree. F. (.about.343.degree. C.) to 1050.degree. F.
(.about.566.degree. C.), or a T10 to T90 boiling range of
650.degree. F. (.about.343.degree. C.) to 1050.degree. F.
(.about.566.degree. C.) Optionally, if the hydroprocessing is also
used to form fuels, it can be possible to use a feed that includes
a lower boiling range portion. Such a feed can have an initial
boiling point and/or a T5 boiling point and/or T10 boiling point of
at least 350.degree. F. (.about.177.degree. C.), or at least
400.degree. F. (.about.204.degree. C.), or at least 450.degree. F.
(.about.232.degree. C.). In particular, such a feed can have a T5
to T95 boiling range of 350.degree. F. (.about.177.degree. C.) to
1100.degree. F. (.about.593.degree. C.), or a T5 to T95 boiling
range of 450.degree. F. (.about.232.degree. C.) to 1050.degree. F.
(.about.566.degree. C.), or a T10 to T90 boiling range of
350.degree. F. (.about.177.degree. C.) to 1050.degree. F.
(.about.566.degree. C.).
[0034] In some aspects, the aromatics content of the feed can be at
least 20 wt %, or at least 30 wt %, or at least 40 wt %, or at
least 50 wt %, or at least 60 wt %. In particular, the aromatics
content can be 20 wt % to 90 wt %, or 40 wt % to 80 wt %, or 50 wt
% to 80 wt %.
[0035] In aspects where the hydroprocessing includes a
hydrotreatment process and/or a sour hydrocracking process, the
feed can have a sulfur content of 500 wppm to 20000 wppm or more,
or 500 wppm to 10000 wppm, or 500 wppm to 5000 wppm. Additionally
or alternately, the nitrogen content of such a feed can be 20 wppm
to 4000 wppm, or 50 wppm to 2000 wppm. In some aspects, the feed
can correspond to a "sweet" feed, so that the sulfur content of the
feed is 10 wppm to 500 wppm and/or the nitrogen content is 1 wppm
to 100 wppm.
[0036] In some embodiments, at least a portion of the feed can
correspond to a feed derived from a biocomponent source. In this
discussion, a biocomponent feedstock refers to a hydrocarbon
feedstock derived from a biological raw material component, from
biocomponent sources such as vegetable, animal, fish, and/or algae.
Note that, for the purposes of this document, vegetable fats/oils
refer generally to any plant based material, and can include
fat/oils derived from a source such as plants of the genus
Jatropha. Generally, the biocomponent sources can include vegetable
fats/oils, animal fats/oils, fish oils, pyrolysis oils, and algae
lipids/oils, as well as components of such materials, and in some
embodiments can specifically include one or more type of lipid
compounds. Lipid compounds are typically biological compounds that
are insoluble in water, but soluble in nonpolar (or fat) solvents.
Non-limiting examples of such solvents include alcohols, ethers,
chloroform, alkyl acetates, benzene, and combinations thereof.
Second Stage Hydrocracking with USY Catalyst
[0037] In various aspects, the second stage for processing of a
feedstock can correspond to exposing at least a portion of the
feedstock to a USY catalyst with a desirable combination of
properties. The properties can be measured prior to the addition of
loaded metals on the catalyst. The USY catalyst can have a unit
cell size of 24.30 .ANG. or less, or 24.27 .ANG. or less, or 24.24
.ANG. or less. Additionally or alternately, the USY catalyst can
have a silica to alumina ratio of at least 50, or at least 70, or
at least 90, or at least 100, or at least 110, or at least 120, or
at least 125, and optionally up to 250 or more, or not more than
1000. This level of silica to alumina ratio can correspond to a
"dealuminated" version of the catalyst. Additionally or
alternately, the USY catalyst can have an alpha value of 20 or
less, or 10 or less. The alpha value test is a measure of the
cracking activity of a catalyst and is described in U.S. Pat. No.
3,354,078 and in the Journal of Catalysis, Vol. 4, p. 527 (1965);
Vol. 6, p. 278 (1966); and Vol. 61, p. 395 (1980), each
incorporated herein by reference as to that description. The
experimental conditions of the test used herein include a constant
temperature of 538.degree. C. and a variable flow rate as described
in detail in the Journal of Catalysis, Vol. 61, p. 395.
[0038] Process conditions in a catalytic dewaxing zone can include
a temperature of from 200 to 450.degree. C., preferably 270 to
400.degree. C., a hydrogen partial pressure of from 1.8 to 34.6
MPag (.about.250 to .about.5000 psi), preferably 4.8 to 20.8 MPag,
a liquid hourly space velocity of from 0.2 to 10 hr.sup.-1,
preferably 0.5 to 3.0 hr.sup.-1, and a hydrogen circulation rate of
from 35.6 to 1781 m.sup.3/m.sup.3 (.about.200 to .about.10,000
SCF/B), preferably 178 to 890.6 m.sup.3/m.sup.3 (.about.1000 to
.about.5000 scf/B). Additionally or alternately, the conditions can
include temperatures in the range of 600.degree. F.
(.about.343.degree. C.) to 815.degree. F. (.about.435.degree. C.),
hydrogen partial pressures of from 500 psig to 3000 psig
(.about.3.5 MPag to .about.20.9 MPag), and hydrogen treat gas rates
of from 213 m.sup.3/m.sup.3 to 1068 m.sup.3/m.sup.3 (.about.1200
SCF/B to .about.6000 SCF/B).
[0039] A USY hydrocracking catalyst can also include a binder
material. Suitable binder materials include materials selected from
metal oxides, zeolites, aluminum phosphates, polymers, carbons, and
clays. Most preferable, the binder is comprised of at least one
metal oxide, preferably selected from silica, alumina,
silica-alumina, amorphous aluminosilicates, boron, titania, and
zirconia. Preferably, the binder is selected from silica, alumina,
and silica-alumina. In a preferred embodiment, the binder is
comprised of pseudoboehmite alumina.
[0040] A catalyst can contain from 0 to 99 wt % binder materials,
or 25 to 80 wt %, or 35 to 75 wt %, or 50 to 65 wt % of the overall
final hydrocracking catalyst. In other preferred embodiments, a
hydrocracking catalyst can be less than 80 wt % binder materials,
or less than 75 wt %, or less than 65 wt %, or less than 50 wt
%.
[0041] A hydrocracking catalyst containing USY zeolite may also
contain additional zeolites or molecular sieves. In some aspects, a
hydrocracking catalyst can further comprise at least one of the
following molecular sieves: beta, ZSM-5, ZSM-11, ZSM-57, MCM-22,
MCM-49, MCM-56, ITQ-7, ITQ-27, ZSM-48, mordenite, zeolite L,
ferrierite, ZSM-23 MCM-68, SSZ-26/-33, SAPO-37, ZSM-12, ZSM-18, and
EMT faujasites. In such aspects, the hydrocracking catalyst can
contain the EMY zeolite in an amount of at least 10 wt %, more
preferably at least at least 25 wt %, and even more preferably at
least 35 wt % or even at least 50 wt % based on the finished
catalyst, particularly when a binder is utilized.
[0042] A USY hydrocracking catalyst can also include at least one
hydrogenating metal component supported on the catalyst. Examples
of such hydrogenating metal components can include one or more
noble metals from Groups 8-10 of the IUPAC periodic table.
Optionally but preferably, the hydrocracking catalyst can include
at least one Group 8/9/10 metal selected from Pt, Pd, Rh and Ru
(noble metals), or combinations thereof. In an aspect, the
hydrocracking catalyst can comprise at least one Group 8/9/10 metal
selected from Pt, Pd, or a combination thereof. In an aspect, the
hydrocracking catalyst can comprise Pt. The at least one
hydrogenating metal may be incorporated into the catalyst by any
technique known in the art. A preferred technique for active metal
incorporation into the catalyst herein is the incipient wetness
technique.
[0043] The amount of active metal in the catalyst can be at least
0.1 wt % based on catalyst, or at least 0.15 wt %, or at least 0.2
wt %, or at least 0.25 wt %, or at least 0.3 wt %, or at least 0.5
wt % based on the catalyst. For embodiments where the Group 8/9/10
metal is Pt, Pd, Rh, Ru, or a combination thereof, the amount of
active metal is preferably from 0.1 to 5 wt %, more preferably from
0.2 to 4 wt %, and even more preferably from 0.25 to 3.5 wt %.
[0044] Examples of suitable zeolite Y catalysts for the processes
described herein can include catalysts based on aggregated Y
zeolite (or Meso-Y) and Extra Mesoporous Y ("EMY") zeolite.
Additional description of aggregated Y zeolite (Meso-Y) can be
found in U.S. Pat. No. 8,778,171, which is incorporated herein by
reference with regard to description of aggregated Y zeolite and
methods for making a catalyst containing aggregated Y zeolite.
Additional description of Extra Mesoporous Y zeolite can be found
in U.S. Pat. No. 8,932,454, which is incorporated herein by
reference with regard to description of EMY zeolite and methods for
making a catalyst containing EMY zeolite.
[0045] Briefly Meso-Y refers to a stabilized aggregated form of
zeolite Y that comprises small primary crystallites and secondary
particles of larger size. At least 80%, e.g., at least 90% or at
least 95%, of the primary crystallites may be aggregated or
clustered to form the secondary particles. The ratio of the average
size (width/diameter) of the secondary particles to the average
size (width/diameter) of the primary crystallites, when the outer
(i.e., external) surfaces of the secondary particles are viewed,
may be at least 3:1, for example at least 5:1 or at least 10:1.
When the outer surfaces of the secondary particles are viewed,
e.g., in an SEM image, the average size of the primary crystallites
in a secondary particle may be 0.5 .mu.m or less, for example 0.3
.mu.m or less, 0.2 .mu.m or less, or 0.1 .mu.m or less, whereas the
average size of the secondary particles may be 0.8 .mu.m or more,
for example 1.0 .mu.m or more or 2.0 .mu.m or more. At least 80%,
e.g., at least 90% or at least 95%, of the aggregated secondary
particles may comprise at least 5, for example at least 10, primary
crystallites. These primary crystallites and secondary particles as
described herein may be observable, e.g., by an SEM under
sufficient conditions including appropriate magnification and
resolution.
[0046] The average sizes of the primary crystallites and secondary
particles can be determined, for instance, by viewing one or more
sufficient two-dimensional SEM images of the secondary particles
and approximating the shape of the primary crystallites and
secondary particles roughly as two-dimensional spherical
projections (circles). When percentages (e.g., 80%, 90%, 95%, or
the like) of primary crystallites and secondary particles are
referred to herein, it should be understood that these percentages
are based on numbers of these particles. Although SEM images
referred to herein do not necessarily depict all of the particles
in an entire batch of primary crystallites and secondary particles,
it should also be understood that the SEM images referred to herein
are viewed as representative of an entire batch of primary
crystallites and secondary particles, including even those
particles not specifically observed.
[0047] The secondary particles may possess an external surface area
of 10 m.sup.2/g or more, for example, 20 m.sup.2/g or more or 40
m.sup.2/g or more, especially after undergoing calcination and/or
steaming. Conventional forms of zeolite Y, such as those having
non-aggregated primary crystallites with a size of 1 micron or
more, tend to have an external surface area of less than 10
m.sup.2/g. The relatively high external surface area of the
secondary particles can be an indication generally of porous gaps
between individual primary crystallites, and specifically of
mesopores in the internal regions of the secondary particles. A
single crystal of comparable size in the form of a generally
spherical shape (with angularity or edges developed) would be
expected to have a smaller external surface area.
[0048] Briefly, an EMY zeolite can be a Y structure zeolite with a
suppressed "small mesopore peak" that is commonly found associated
within the "small mesopores" (30 to 50 .ANG. pore diameters) of
commercial Y-type zeolites, while maintaining a substantial volume
of pores in the "large mesopores" (greater than 50 to 500 .ANG.
pore diameters) of the zeolite. International Union of Pure and
Applied Chemistry ("IUPAC") standards defines "mesopores" as having
pore diameters greater than 20 to less than 500 Angstroms (.ANG.).
However, the standard nitrogen desorption measurements as used
herein do not provide pore volume data below .about.22 .ANG..
Additionally, since the "small mesopore peak" found in Y zeolites
are substantially confined between the 30 and 50 .ANG. ranges, it
is sufficient to define the measurable mesoporous pore diameter
range for the purposes of this invention as pore diameters from 30
to 500 Angstroms (.ANG.).
[0049] As utilized herein, the terms "Small Mesopore(s)" or "Small
Mesoporous" are defined as those pore structures in the zeolite
crystal with a pore diameter of 30 to 50 Angstroms (.ANG.).
Similarly, the terms "Large Mesopore(s)" or "Large Mesoporous" as
utilized herein are defined as those pore structures in the zeolite
crystal with a pore diameter of greater than 50 to 500 Angstroms
(.ANG.). The terms "Mesopore(s)" or "Mesoporous" when utilized
herein alone (i.e., not in conjunction with a "small" or "large"
adjective) are defined herein as those pore structures in the
zeolite crystal with a pore diameter of 30 to 500 Angstroms
(.ANG.). Unless otherwise noted, the unit of measurement used for
mesoporous pore diameters herein is in Angstroms (.ANG.).
[0050] In various aspects, the Large-to-Small Pore Volume Ratio or
"LSPVR" of an EMY zeolite can be at least 4.0, more preferably at
least 5.0, and even more preferably, the LSPVR of the EMY can be at
least 6.0. Additionally or alternately, the "Large-to-Small Pore
Volume Ratio" of an EMY can be at least 10.0, or at least 12.0, or
at least 15.0 after long-term deactivation steaming at 1400.degree.
F. for 16 hours.
[0051] EMY zeolites can have a Large Mesopore Volume of at least
0.03 cm.sup.3/g, more preferably at least 0.05 cm.sup.3/g, and even
more preferably at least 0.07 cm.sup.3/g. Additionally or
alternately, EMY zeolites can have a Small Mesopore Peak of less
than 0.15 cm.sup.3/g, or less 0.13 cm.sup.3/g, or less than 0.11
cm.sup.3/g.
First Hydroprocessing Stage--Hydrotreating and/or Hydrocracking
[0052] In various aspects, a first hydroprocessing stage can be
used to improve one or more qualities of a feedstock for lubricant
base oil production. Examples of improvements of a feedstock can
include, but are not limited to, reducing the heteroatom content of
a feed, performing conversion on a feed to provide viscosity index
uplift, and/or performing aromatic saturation on a feed.
[0053] With regard to heteroatom removal, the conditions in the
initial hydroprocessing stage (hydrotreating and/or hydrocracking)
can be sufficient to reduce the sulfur content of the
hydroprocessed effluent to 250 wppm or less, or 200 wppm or less,
or 150 wppm or less, or 100 wppm or less, or 50 wppm or less, or 25
wppm or less, or 10 wppm or less. In particular, the sulfur content
of the hydroprocessed effluent can be 1 wppm to 250 wppm, or 1 wppm
to 50 wppm, or 1 wppm to 10 wppm. Additionally or alternately, the
conditions in the initial hydroprocessing stage can be sufficient
to reduce the nitrogen content to 100 wppm or less, or 50 wppm or
less, or 25 wppm or less, or 10 wppm or less. In particular, the
nitrogen content can be 1 wppm to 100 wppm, or 1 wppm to 25 wppm,
or 1 wppm to 10 wppm.
[0054] In aspects that include hydrotreating as part of the initial
hydroprocessing stage, the hydrotreating catalyst can comprise any
suitable hydrotreating catalyst, e.g., a catalyst comprising at
least one Group 8-10 non-noble metal (for example selected from Ni,
Co, and a combination thereof) and at least one Group 6 metal (for
example selected from Mo, W, and a combination thereof), optionally
including a suitable support and/or filler material (e.g.,
comprising alumina, silica, titania, zirconia, or a combination
thereof). The hydrotreating catalyst according to aspects of this
invention can be a bulk catalyst or a supported catalyst.
Techniques for producing supported catalysts are well known in the
art. Techniques for producing bulk metal catalyst particles are
known and have been previously described, for example in U.S. Pat.
No. 6,162,350, which is hereby incorporated by reference. Bulk
metal catalyst particles can be made via methods where all of the
metal catalyst precursors are in solution, or via methods where at
least one of the precursors is in at least partly in solid form,
optionally but preferably while at least another one of the
precursors is provided only in a solution form. Providing a metal
precursor at least partly in solid form can be achieved, for
example, by providing a solution of the metal precursor that also
includes solid and/or precipitated metal in the solution, such as
in the form of suspended particles. By way of illustration, some
examples of suitable hydrotreating catalysts are described in one
or more of U.S. Pat. Nos. 6,156,695, 6,162,350, 6,299,760,
6,582,590, 6,712,955, 6,783,663, 6,863,803, 6,929,738, 7,229,548,
7,288,182, 7,410,924, and 7,544,632, U.S. Patent Application
Publication Nos. 2005/0277545, 2006/0060502, 2007/0084754, and
2008/0132407, and International Publication Nos. WO 04/007646, WO
2007/084437, WO 2007/084438, WO 2007/084439, and WO 2007/084471,
inter alia. Preferred metal catalysts include cobalt/molybdenum
(1-10% Co as oxide, 10-40% Mo as oxide), nickel/molybdenum (1-10%
Ni as oxide, 10-40% Co as oxide), or nickel/tungsten (1-10% Ni as
oxide, 10-40% W as oxide) on alumina.
[0055] In various aspects, hydrotreating conditions can include
temperatures of 200.degree. C. to 450.degree. C., or 315.degree. C.
to 425.degree. C.; pressures of 250 psig (.about.1.8 MPag) to 5000
psig (.about.34.6 MPag) or 500 psig (.about.3.4 MPag) to 3000 psig
(.about.20.8 MPag), or 800 psig (.about.5.5 MPag) to 2500 psig
(.about.17.2 MPag); Liquid Hourly Space Velocities (LHSV) of 0.2-10
h.sup.-1; and hydrogen treat rates of 200 scf/B (35.6
m.sup.3/m.sup.3) to 10,000 scf/B (1781 m.sup.3/m.sup.3), or 500 (89
m.sup.3/m.sup.3) to 10,000 scf/B (1781 m.sup.3/m.sup.3).
[0056] Hydrotreating catalysts are typically those containing Group
6 metals, and non-noble Group 8-10 metals, i.e., iron, cobalt and
nickel and mixtures thereof. These metals or mixtures of metals are
typically present as oxides or sulfides on refractory metal oxide
supports. Suitable metal oxide supports include low acidic oxides
such as silica, alumina or titania, preferably alumina. In some
aspects, preferred aluminas can correspond to porous aluminas such
as gamma or eta having average pore sizes from 50 to 200 .ANG., or
75 to 150 .ANG.; a surface area from 100 to 300 m.sup.2/g, or 150
to 250 m.sup.2/g; and/or a pore volume of from 0.25 to 1.0
cm.sup.3/g, or 0.35 to 0.8 cm.sup.3/g. The supports are preferably
not promoted with a halogen such as fluorine as this generally
increases the acidity of the support.
[0057] Alternatively, the hydrotreating catalyst can be a bulk
metal catalyst, or a combination of stacked beds of supported and
bulk metal catalyst. By bulk metal, it is meant that the catalysts
are unsupported wherein the bulk catalyst particles comprise 30-100
wt. % of at least one Group 8-10 non-noble metal and at least one
Group 6 metal, based on the total weight of the bulk catalyst
particles, calculated as metal oxides and wherein the bulk catalyst
particles have a surface area of at least 10 m.sup.2/g. It is
furthermore preferred that the bulk metal hydrotreating catalysts
used herein comprise 50 to 100 wt %, and even more preferably 70 to
100 wt %, of at least one Group 8-10 non-noble metal and at least
one Group 6 metal, based on the total weight of the particles,
calculated as metal oxides. The amount of Group 6 and Group 8-10
non-noble metals can easily be determined VIB TEM-EDX.
[0058] Bulk catalyst compositions comprising one Group 8-10
non-noble metal and two Group 6 metals are preferred. It has been
found that in this case, the bulk catalyst particles are
sintering-resistant. Thus the active surface area of the bulk
catalyst particles is maintained during use. The molar ratio of
Group 6 to Group 8-10 non-noble metals ranges generally from
10:1-1:10 and preferably from 3:1-1:3, In the case of a core-shell
structured particle, these ratios of course apply to the metals
contained in the shell. If more than one Group 6 metal is contained
in the bulk catalyst particles, the ratio of the different Group 6
metals is generally not critical. The same holds when more than one
Group 8-10 non-noble metal is applied. In the case where molybdenum
and tungsten are present as Group 6 metals, the molybenum:tungsten
ratio preferably lies in the range of 9:1-1:9. Preferably the Group
8-10 non-noble metal comprises nickel and/or cobalt. It is further
preferred that the Group 6 metal comprises a combination of
molybdenum and tungsten. Preferably, combinations of
nickel/molybdenum/tungsten and cobalt/molybdenum/tungsten and
nickel/cobalt/molybdenum/tungsten are used. These types of
precipitates appear to be sinter-resistant. Thus, the active
surface area of the precipitate is maintained during use. The
metals are preferably present as oxidic compounds of the
corresponding metals, or if the catalyst composition has been
sulfided, sulfidic compounds of the corresponding metals.
[0059] In some optional aspects, the bulk metal hydrotreating
catalysts used herein have a surface area of at least 50 m.sup.2/g
and more preferably of at least 100 m.sup.2/g. In such aspects, it
is also desired that the pore size distribution of the bulk metal
hydrotreating catalysts be approximately the same as the one of
conventional hydrotreating catalysts. Bulk metal hydrotreating
catalysts can have a pore volume of 0.05-5 ml/g, or of 0.1-4 ml/g,
or of 0.1-3 ml/g, or of 0.1-2 tag determined by nitrogen
adsorption. Preferably, pores smaller than 1 nm are not present.
The bulk metal hydrotreating catalysts can have a median diameter
of at least 50 nm, or at least 100 nm. The bulk metal hydrotreating
catalysts can have a median diameter of not more than 5000 .mu.m,
or not more than 3000 .mu.m. In an embodiment, the median particle
diameter lies in the range of 0.1-50 .mu.m and most preferably in
the range of 0.5-50 .mu.m.
[0060] In aspects that include hydrocracking as part of the initial
hydroprocessing stage, the initial stage hydrocracking catalyst can
comprise any suitable or standard hydrocracking catalyst, for
example, a zeolitic base selected from zeolite Beta, zeolite X,
zeolite Y, faujasite, ultrastable Y (USY), dealuminized Y (Deal Y),
Mordenite, ZSM-3, ZSM-4, ZSM-18, ZSM-20, ZSM-48, and combinations
thereof, which zeolitic base can advantageously be loaded with one
or more active metals (e.g., either (i) a Group 8-10 noble metal
such as platinum and/or palladium or (ii) a Group 8-10 non-noble
metal such nickel, cobalt, iron, and combinations thereof, and a
Group 6 metal such as molybdenum and/or tungsten). In this
discussion, zeolitic materials are defined to include materials
having a recognized zeolite framework structure, such as framework
structures recognized by the International Zeolite Association.
Such zeolitic materials can correspond to silicoaluminates,
silicoaluminophosphates, aluminophosphates, and/or other
combinations of atoms that can be used to form a zeolitic framework
structure. In addition to zeolitic materials, other types of
crystalline acidic support materials may also be suitable.
Optionally, a zeolitic material and/or other crystalline acidic
material may be mixed or bound with other metal oxides such as
alumina, titania, and/or silica.
[0061] A hydrocracking process in the first stage (or otherwise
under sour conditions) can be carried out at temperatures of
200.degree. C. to 450.degree. C., hydrogen partial pressures of
from 250 psig to 5000 psig (.about.1.8 MPag to .about.34.6 MPag),
liquid hourly space velocities of from 0.2 h.sup.-1 to 10 h.sup.-1,
and hydrogen treat gas rates of from 35.6 m.sup.3/m.sup.3 to 1781
m.sup.3/m.sup.3 (.about.200 SCF/B to .about.10,000 SCF/B),
Typically, in most cases, the conditions can include temperatures
in the range of 300.degree. C. to 450.degree. C., hydrogen partial
pressures of from 500 psig to 2000 psig (.about.3.5 MPag to
.about.13.9 MPag), liquid hourly space velocities of from 0.3
h.sup.-1 to 2 h.sup.-1 and hydrogen treat gas rates of from 213
m.sup.3/m.sup.3 to 1068 m.sup.3/m.sup.3 (.about.1200 SCF/B to
.about.6000 SCF/B).
Additional Second Stage Processing--Dewaxing and
Hydrofinishing/Aromatic Saturation
[0062] After hydroprocessing in the first stage, the hydroprocessed
effluent can be separated. In some aspects the separation can
correspond to a separation that is primarily focused on separation
of contaminant gases (H.sub.2S, NH.sub.3) that are generated during
heteroatom removal. In some aspects, additional lower boiling
portions of the hydroprocessed effluent can be separated out, such
as naphtha and/or diesel boiling range portions. In such aspects, a
lubricant boiling range portion (optionally including a diesel
boiling range portion and/or other hydroprocessed bottoms) can be
further processed by catalytic dewaxing and/or hydrofinishing or
aromatic saturation.
[0063] In various aspects, catalytic dewaxing can be included as
part of a second or subsequent processing stage. Preferably, the
dewaxing catalysts are zeolites (and/or zeolitic crystals) that
perform dewaxing primarily by isomerizing a hydrocarbon feedstock.
More preferably, the catalysts are zeolites with a unidimensional
pore structure. Suitable catalysts include 10-member ring pore
zeolites, such as EU-1, ZSM-35 (or ferrierite), ZSM-11, ZSM-57,
NU-87, SAPO-11, and ZSM-22. Preferred materials are EU-2, EU-11,
ZBM-30, ZSM-48, or ZSM-23. ZSM-48 is most preferred. Note that a
zeolite having the ZSM-23 structure with a silica to alumina ratio
of from 20:1 to 40:1 can sometimes be referred to as SSZ-32. Other
zeolitic crystals that are isostructural with the above materials
include Theta-1, NU-10, EU-13, KZ-1, and NU-23.
[0064] In various embodiments, the dewaxing catalysts can further
include a metal hydrogenation component. The metal hydrogenation
component is typically a Group 6 and/or a Group 8-10 metal.
Preferably, the metal hydrogenation component is a Group 8-10 noble
metal. Preferably, the metal hydrogenation component is Pt, Pd, or
a mixture thereof. In an alternative preferred embodiment, the
metal hydrogenation component can be a combination of a non-noble
Group 8-10 metal with a Group 6 metal. Suitable combinations can
include Ni, Co, or Fe with Mo or W, preferably Ni with Mo or W.
[0065] The metal hydrogenation component may be added to the
dewaxing catalyst in any convenient manner. One technique for
adding the metal hydrogenation component is by incipient wetness.
For example, after combining a zeolite and a binder, the combined
zeolite and binder can be extruded into catalyst particles. These
catalyst particles can then be exposed to a solution containing a
suitable metal precursor. Alternatively, metal can be added to the
catalyst by ion exchange, where a metal precursor is added to a
mixture of zeolite (or zeolite and binder) prior to extrusion.
[0066] The amount of metal in the dewaxing catalyst can be at least
0.1 wt % based on catalyst, or at least 0.15 wt %, or at least 0.2
wt %, or at least 0.25 wt %, or at least 0.3 wt %, or at least 0.5
wt % based on catalyst. The amount of metal in the catalyst can be
20 wt % or less based on catalyst, or 10 wt % or less, or 5 wt % or
less, or 2.5 wt % or less, or 1 wt % or less. For aspects where the
metal is Pt, Pd, another Group 8-10 noble metal, or a combination
thereof, the amount of metal can be from 0.1 to 5 wt %, preferably
from 0.1 to 2 wt %, or 0.25 to 1.8 wt %, or 0.4 to 1.5 wt %. For
aspects where the metal is a combination of a non-noble Group 8-10
metal with a Group 6 metal, the combined amount of metal can be
from 0.5 wt % to 20 wt %, or 1 wt % to 15 wt %, or 2.5 wt % to 10
wt %.
[0067] Preferably, a dewaxing catalyst can be a catalyst with a low
ratio of silica, to alumina. For example, for ZSM-48, the ratio of
silica to alumina in the zeolite can be less than 200:1, or less
than 110:1, or less than 100:1, or less than 90:1, or less than
80:1. In particular, the ratio of silica to alumina can be from
30:1 to 200:1, or 60:1 to 110:1, or 70:1 to 100:1.
[0068] A dewaxing catalyst can also include a binder. In some
embodiments, the dewaxing catalysts used in process according to
the invention are formulated using a low surface area binder, a low
surface area binder represents a binder with a surface area of 100
m.sup.2/g or less, or 80 m.sup.2/g or less, or 70 m.sup.2/g or
less, such as down to 40 m.sup.2/g or still lower.
[0069] Alternatively, the binder and the zeolite particle size can
be selected to provide a catalyst with a desired ratio of micropore
surface area to total surface area. In dewaxing catalysts used
according to the invention, the micropore surface area corresponds
to surface area from the unidimensional pores of zeolites in the
dewaxing catalyst. The total surface corresponds to the micropore
surface area plus the external surface area. Any binder used in the
catalyst will not contribute to the micropore surface area and will
not significantly increase the total surface area of the catalyst.
The external surface area represents the balance of the surface
area of the total catalyst minus the micropore surface area. Both
the binder and zeolite can contribute to the value of the external
surface area. Preferably, the ratio of micropore surface area to
total surface area for a dewaxing catalyst will be equal to or
greater than 25%.
[0070] A zeolite (or other zeolitic material) can be combined with
binder in any convenient manner. For example, a bound catalyst can
be produced by starting with powders of both the zeolite and
binder, combining and mulling the powders with added water to form
a mixture, and then extruding the mixture to produce a bound
catalyst of a desired size. Extrusion aids can also be used to
modify the extrusion flow properties of the zeolite and binder
mixture. The amount of framework alumina in the catalyst may range
from 0.1 to 3.33 wt %, or 0.1 to 2.7 wt %, or 0.2 to 2 wt %, or 0.3
to 1 wt %.
[0071] In yet another embodiment, a binder composed of two or more
metal oxides can also be used. In such an embodiment, the weight
percentage of the low surface area binder is preferably greater
than the weight percentage of the higher surface area binder.
[0072] Alternatively, if both metal oxides used for forming a mixed
metal oxide binder have a sufficiently low surface area, the
proportions of each metal oxide in the binder are less important.
When two or more metal oxides are used to form a binder, the two
metal oxides can be incorporated into the catalyst by any
convenient method. For example, one binder can be mixed with the
zeolite during formation of the zeolite powder, such as during
spray drying. The spray dried zeolite/binder powder can then be
mixed with the second metal oxide binder prior to extrusion. In an
aspect, the dewaxing catalyst can be self-bound and does not
contain a binder. Process conditions in a catalytic dewaxing zone
can include a temperature of from 200 to 450.degree. C., preferably
270 to 400.degree. C., a hydrogen partial pressure of from 1.8 to
34.6 mPa (.about.250 to .about.5000 psi), preferably 4.8 to 20.8
mPa, a liquid hourly space velocity of from 0.2 to 10 hr.sup.-1,
preferably 0.5 to 3.0 hr.sup.-1, and a hydrogen circulation rate of
from 35.6 to 1781 m.sup.3/m.sup.3 (.about.200 to .about.10,000
scf/B), preferably 178 to 890.6 m.sup.3/m.sup.3 (.about.1000 to
.about.5000 scf/B).
[0073] In various aspects, a hydrofinishing and/or aromatic
saturation process can also be provided. The hydrofinishing and/or
aromatic saturation can occur prior to dewaxing and/or after
dewaxing. The hydrofinishing and/or aromatic saturation can occur
either before or after fractionation. If hydrofinishing and/or
aromatic saturation occurs after fractionation, the hydrofinishing
can be performed on one or more portions of the fractionated
product, such as being performed on one or more lubricant base
stock portions. Alternatively, the entire effluent from the last
hydrocracking or dewaxing process can be hydrofinished and/or
undergo aromatic saturation.
[0074] In some situations, a hydrofinishing process and an aromatic
saturation process can refer to a single process performed using
the same catalyst. Alternatively, one type of catalyst or catalyst
system can be provided to perform aromatic saturation, while a
second catalyst or catalyst system can be used for hydrofinishing.
Typically a hydrofinishing and/or aromatic saturation process will
be performed in a separate reactor from dewaxing or hydrocracking
processes for practical reasons, such as facilitating use of a
lower temperature for the hydrofinishing or aromatic saturation
process. However, an additional hydrofinishing reactor following a
hydrocracking or dewaxing process but prior to fractionation could
still be considered part of a second stage of a reaction system
conceptually.
[0075] Hydrofinishing and/or aromatic saturation catalysts can
include catalysts containing Group 6 metals, Group 8-10 metals, and
mixtures thereof. In an embodiment, preferred metals include at
least one metal sulfide having a strong hydrogenation function. In
another embodiment, the hydrofinishing catalyst can include a Group
8-10 noble metal, such as Pt, Pd, or a combination thereof. The
mixture of metals may also be present as bulk metal catalysts
wherein the amount of metal is 30 wt. % or greater based on
catalyst. Suitable metal oxide supports include low acidic oxides
such as silica, alumina, silica-aluminas or titania, preferably
alumina. The preferred hydrofinishing catalysts for aromatic
saturation will comprise at least one metal having relatively
strong hydrogenation function on a porous support. Typical support
materials include amorphous or crystalline oxide materials such as
alumina, silica, and silica-alumina. The support materials may also
be modified, such as by halogenation, or in particular
fluorination. The metal content of the catalyst is often as high as
20 weight percent for non-noble metals. In an embodiment, a
preferred hydrofinishing catalyst can include a crystalline
material belonging to the M41S class or family of catalysts. The
M41S family of catalysts are mesoporous materials having high
silica content. Examples include MCM-41, MCM-48 and MCM-50. A
preferred member of this class is MCM-41. If separate catalysts are
used for aromatic saturation and hydrofinishing, an aromatic
saturation catalyst can be selected based on activity and/or
selectivity for aromatic saturation, while a hydrofinishing
catalyst can be selected based on activity for improving product
specifications, such as product color and polynuclear aromatic
reduction.
[0076] Hydrofinishing conditions can include temperatures from
125.degree. C. to 425.degree. C., preferably 180.degree. C. to
280.degree. C., total pressures from 500 psig (.about.3.4 MPag) to
3000 psig (.about.20.7 MPag), preferably 1500 psig (.about.10.3
MPag) to 2500 psig (.about.17.2 MPag), and liquid hourly space
velocity (LHSV) from 0.1 hr.sup.-1 to 5 hr.sup.-1, preferably 0.5
hr.sup.-1 to 1.5 hr.sup.-1.
[0077] A second fractionation or separation can be performed at one
or more locations after a second or subsequent stage. In some
aspects, a fractionation can be performed after hydrocracking in
the second stage in the presence of the USY catalyst under sweet
conditions. At least a lubricant boiling range portion of the
second stage hydrocracking effluent can then be sent to a dewaxing
and/or hydrofinishing reactor for further processing. In some
aspects, hydrocracking and dewaxing can be performed prior to a
second fractionation. In some aspects, hydrocracking, dewaxing, and
aromatic saturation can be performed prior to a second
fractionation. Optionally, aromatic saturation and/or
hydrofinishing can be performed before a second fractionation,
after a second fractionation, or both before and after.
Example 1: Production of Advantaged Basestocks
[0078] A hydrocracking process for lubes can be used to produce
compositionally advantaged base stocks with superior low
temperature and oxidation performance. A wide-cut feed is processed
through a first stage which is primarily a hydrotreating unit which
boosts viscosity index (VI) and removes sulfur and nitrogen. This
is followed by a stripping section where light ends and diesel are
removed. The heavier lube fraction then enters the second stage
where hydrocracking, dewaxing, and hydrofinishing are done. This
corresponds to the configuration shown in FIG. 2, although the
configuration in FIG. 3 could alternatively be used. This
combination of feed and process can produce a base stock with
unique compositional characteristics. These unique compositional
characteristics are observed in both the lower and higher viscosity
base stocks produced.
[0079] The lubricating oil base stocks can be produced by
co-processing a wide-cut feed to hit conventional VI targets for
the low viscosity cut which yields the low viscosity product with
unique compositional characteristics as compared with
conventionally processed low viscosity base stocks. The lubricating
oil base stock composition can be determined using a combination of
advanced analytical techniques including gas chromatography mass
spectrometry (GCMS), supercritical fluid chromatography (SFC),
carbon-13 nuclear magnetic resonance (13C NMR), proton nuclear
magnetic resonance (proton-NMR), two dimensional gas chromatography
(2DGC) and differential scanning calorimetry (DSC). Examples of
Group II low viscosity lubricating oil base stocks of this
disclosure and having a kinematic viscosity at 100.degree. C. in
the range of 4-6 cSt are described in FIG. 4. For reference, the
low viscosity lubricating oil base stocks of this disclosure are
compared with typical Group II low viscosity base stocks having the
same viscosity range.
[0080] The co-processed high viscosity product from the above
described process can also show the unique compositional
characteristics described herein. Examples of such Group II high
viscosity lubricating oil base stocks having kinematic viscosity at
100.degree. C. in the range of 10-14 cSt are described in FIG. 5.
For reference, the high viscosity lubricating oil base stocks of
this disclosure are compared with typical Group II high viscosity
base stocks having the same viscosity range.
[0081] The Group II base stocks with previously unique compositions
(examples in FIGS. 4 and 5) produced by the hydrocracking process
exhibit a range of base stock viscosities from 3.5 cst to 14 cst.
These differences in composition include a difference in
distribution of the cycloparaffin ring species and lead to larger
relative amounts of one ring compared to multi-ring cycloparaffins.
A cycloparaffin performance ratio is defined as the ratio of
monocycloparaffinic (hydrogen deficiency X-class of 0) to
multi-ring cycloparaffinic and naphthenoaromatic species (sum of
species with hydrogen deficiency X-class of -2, -4, -6, -8, and
-10) in said base stock relative to the same ratio in a Group II
commercially available sample in 2016 or earlier with a kinematic
viscosity at 100.degree. C. within 0.3 cSt as the test sample,
wherein the amounts of monocycloparaffinic to multi-ring
cycloparaffinic and naphthenoaromatic species are all measured
using GCMS on the same instrument at the same calibration. FIGS. 4
and 5, referring to line 14 in each, show the cycloparaffin
performance ratio for the low viscosity product exceeding 1.05, or
1.1, or 1.2, or 1.3 in the base stocks of this disclosure, and in
the high viscosity product exceeding 1.05, or 1.1, or even more
preferably exceeding 1.2, or 1.3, or 1.4 in the base stocks of this
disclosure.
[0082] Additionally, in these base stocks of this disclosure, the
absolute value of multi-ring cycloparaffins as show in FIGS. 4 and
5, rows 15, 16, and 17 of each, for 2+, 3+, 4+ring cycloparaffins
is lower in the base stocks of this disclosure as compared to
commercially known stocks across the range of viscosities.
Specifically, the example base stocks of this disclosure show less
than 35.7% 2+ring cycloparaffins, less than 11.0% 3+ring
cycloparaffins and less than 3.7% 4+ring cycloparaffins in the low
viscosity product, and less than 39% 2+ring cycloparaffins, less
than 10.8% 3+ring cycloparaffins and less than 3.2% 4+ring
cycloparaffins for the high viscosity product. The lower amounts of
the multi-ring cycloparaffins can also be seen by looking at
individual numbers of 3 ring species (FIGS. 4 and 5, line 7 of
each); less than 7.8% for the low viscosity product and less than
7.9% for the high viscosity product. Additionally, the base stocks
of this disclosure also show higher amounts of the
monocycloparaffin species across the full viscosity range; greater
than 40.7% for the low viscosity base stocks and greater than 38.8%
for the high viscosity base stocks.
[0083] Further, using a wide cut feed gives additional advantages
on the heavier base stocks co-produced with the lighter base
stocks. As seen in FIG. 5, line 4 thereof, the high viscosity
stocks show significantly lower total cycloparaffin content (less
than 75%) compared to commercial base stocks, averaging closer to
80%. This is also evidenced by higher VI, exceeding 109.3 where the
base stocks of this disclosure have VI in the 109-112 range.
[0084] Additionally, the high viscosity base stocks show lower
degree of branching on the iso-paraffin portion of the species as
evidenced by greater than 13.3 epsilon carbon atoms per 100 carbon
atoms as measured by 13C-NMR, and a greater number of long alkyl
branches on iso-paraffin portion of the species as evidence by
greater than 2.8 alpha carbon atoms per 100 carbon atoms as
measured by 13C-NMR (FIG. 5, lines 18 and 20). Some unique
combinations of properties are also seen specifically in the low
viscosity base stock co-produced with the high viscosity product.
For example, the low viscosity base stocks of this disclosure have
epsilon carbon content less than 12% while retaining viscosity
index greater than 110 (FIG. 4, lines 18 and 3).
[0085] The base stocks of this disclosure have lower contents of
total cycloparaffins as compared to the typical Group II base
stocks. This is believed to provide the VI advantage of the base
stocks of this disclosure over competitive base stocks.
Surprisingly, the base stocks of this disclosure also have higher
content of the X=0 ring class species (corresponding to
monocycloparaffinic species), despite the lower overall
cycloparaffin content and naphthenoaromatic species content. While
not being bound by theory, one hypothesis for the lower amounts of
multi-ring cycloparaffins and naphthenoaromatics is that ring
opening reactions that lead to low multi-ring cycloparaffins and
naphthenoaromatics may have high selectivity under the process
conditions used to make the base stocks of this disclosure. The
process scheme used to make the base stocks of this disclosure
enables greater use of noble metal catalysts having acidic sites
under low sulfur (sweet) processing conditions that may favor ring
opening reactions that potentially improve VI.
Example 2: Aromatic Saturation During Sour and Sweet Operation
[0086] FIGS. 1-3 provide configurations where a feed is initially
hydroprocessed under sour conditions (e.g., sulfur content greater
than 250 wppm) followed by hydrocracking of at least a lubricant
boiling range portion in the presence of a USY catalyst as
described above under sweet conditions (e.g., combined liquid phase
and gas phase sulfur equivalent to sulfur content of 100 wppm or
less.) The benefits of performing hydrocracking in the presence of
the USY catalyst under sweet conditions can be shown in comparison
with hydrocracking under sour conditions according to a
conventional configuration.
[0087] In this example, an aromatic feedstock suitable for
lubricant base stock production was processed in two different
configurations. Configuration A corresponds to a configuration
where hydrotreating and hydrocracking are performed in a single
stage. Commercially available hydrotreating catalysts and
commercially available base metal hydrocracking catalyst was used.
Configuration B corresponds to a configuration similar to FIG. 1.
In Configuration B, commercially available hydrotreatment catalysts
were used in a first stage to reduce the sulfur content of the feed
to less than 100 wppm. The first stage effluent was then separated
to remove light ends and to also remove portions of the feed having
a boiling point of less than 700.degree. F. (.about.371.degree.
C.). The remaining lubricant boiling range fraction was then
hydrocracked in the presence of a noble metal USY catalyst. The
noble metal USY catalyst was a USY catalyst with a unit cell size
of less than 24.30, a silica to alumina ratio of greater than 50,
and an alpha value of 20 or less. The noble metal USY catalyst
further included 1.0 wt % of Pt, based on the weight of the
support. The hydrogen pressure for both configurations was 2200
psig (.about.15.2 MPag). The temperature was selected to generate
effluents having less than 100 wppm of sulfur, and also to achieve
a desired level of feed conversion relative to 700.degree. F.
(.about.371.degree. C.). For Configuration B, the amount of
conversion is the total conversion across both the hydrotreatment
and hydrocracking reactors.
[0088] FIG. 6 shows the aromatics content (wt %) in the
hydroprocessed effluent for Configuration A (squares, sour
hydrocracking) and Configuration B (circles, sweet hydrocracking).
The amount of aromatics in the hydroprocessed effluent is shown
relative to the amount of combined 700.degree. F.
(.about.371.degree. C.) conversion performed during hydroprocessing
(hydrotreating plus hydrocracking). With regard to aromatic
content, the aromatic content of a feedstock (such as a lubricant
boiling range feed) can be determined by any convenient method.
ASTM D2007 provides an example of a method for measuring aromatics
in lubricant boiling range feed.
[0089] The square at 0% conversion indicates the aromatics content
of the feed, which was roughly 65 wt %. At 700.degree. F.
(.about.371.degree. C.) conversion levels of .about.25% or less,
the conversion and aromatic saturation shown in FIG. 6 corresponds
to aromatic saturation and conversion due to hydrotreating only.
Conversion levels greater than 25% correspond to hydrotreating
followed by hydrocracking. At higher levels of conversion, sweet
hydrocracking in the presence of the USY catalyst resulted in
aromatic contents in the hydrocracked effluent of roughly .about.2
to .about.4 wt %. By contrast, increasing the 700.degree. F.
(.about.371.degree. C.) conversion under sour conditions was
effective for achieving up to 60% conversion of the feed, but the
aromatics content was at least .about.35 wt % at all levels of
conversion for sour hydrocracking. This demonstrates the ability of
sweet hydrocracking in the presence of a USY catalyst to provide
improved aromatic saturation relative to sour hydrocracking.
Example 3: Aromatic Saturation with Liquid Quench
[0090] Processing of a feed similar to the feed in Example 2 was
modeled using an empirical model that was fit and verified against
both lab scale and commercial scale hydroprocessing runs.
Processing of the feed was modeled using two different
configurations. Configuration C corresponded to a configuration
similar FIG. 2, while Configuration D corresponded to configuration
similar to FIG. 3. Configuration C was modeled to include use of a
quench gas to reduce the temperature of the hydrocracked effluent
prior to dewaxing. Configuration D was modeled to include a recycle
of 25 wt % of the dewaxed effluent for combination with the
hydrocracked effluent.
[0091] In both configurations, an initial sour hydroprocessing
stage was used to reduce heteroatom content. Hydrocracking,
dewaxing, and hydrofinishing were then performed in the second
"sweet" stage. For both configurations, a noble metal USY catalyst
(as described in Example 2) was used for hydrocracking, a 0.6 wt %
Pt-ZSM-48 catalyst was used for dewaxing, and commercially
available hydrofinishing catalyst was used for hydrofinishing.
After hydrofinishing, the (non-recycled) portion of the dewaxed
effluent was fractionated to form fuels fractions, a light neutral
base stock (4-6 cSt), and a heavy neutral base stock (10-14
cSt).
[0092] The hydrocracking in both configurations was performed at
2200 psig (.about.15.2 MPag). Table 1 below provides additional
details regarding the temperatures during the modeled processing
runs. In Table 1, EIT refers to estimated internal temperature,
which is roughly an average of the inlet and exit temperatures for
a reactor.
TABLE-US-00001 TABLE 1 Configuration C Configuration D HDC EIT
.degree. C. 367 367 Dewax Feed temperature (inlet) .degree. C. 367
352 Dewax EIT .degree. C. 343 343 High P quench gas rate base 30%
of base Light Neutral aromatics, wt % ~2.4 wt % ~1.2 wt % Heavy
Neutral aromatics, wt %. ~2.2 wt % ~1.3 wt %
[0093] As shown in Table 1 above, the hydrocracking reactors in
Configurations C and D were run at the same temperature. The
dewaxing reactors were also run at the same temperature, which was
roughly 25.degree. C. cooler than the hydrocracking reactors. Using
the gas phase quench only in Configuration C, the hydrocracked
effluent could only be cooled by roughly 10.degree. C., which
caused the input to the dewaxing reactor to have roughly the same
temperature as the estimated internal temperature of the
hydrocracking reactor. By contrast, the liquid quench in
Configuration D was able to cool the hydrocracked effluent (or
dewaxing feed) much more substantially, corresponding to roughly
25.degree. C. of cooling. Thus, the feed to dewaxing in
Configuration D is closer to the average temperature of the
dewaxing reactor. Additionally, Configuration D allows the recycled
portion of the dewaxing effluent to be exposed to the dewaxing and
hydrofinishing catalysts a second time, allowing for further
reduction in aromatics and pour points This led to improvements in
oxidation time as measured by the Rotary Pressure Vessel Oxidation
test. A turbine oil blended with the heavy neutral sample from
Configuration C gave a 825 minutes RPVOT time, while the RPVOT time
in the same formulation blended with the heavy neutral sample from
Configuration D gave a 1006 minutes RPVOT time. This would also be
expected to lead to improvements in low temperature
performance.
ADDITIONAL EMBODIMENTS
Embodiment 1
[0094] A method for producing a lubricant boiling range product,
comprising: hydroprocessing a feedstock comprising a 650.degree. F.
(.about.343.degree. C.) portion under first hydroprocessing
conditions to form a hydroprocessed effluent; fractionating at
least a portion of the hydroprocessed effluent to form at least a
first fuels boiling range fraction and a second fraction, the
second fraction comprising a lubricant boiling range portion;
hydrocracking the second fraction in the presence of hydrocracking
catalyst under hydrocracking conditions to form a hydrocracked
effluent, the hydrocracking catalyst comprising USY zeolite having
a unit cell size of 24.30 .ANG. or less, a silica to alumina ratio
of at least 50, and an Alpha value of 20 or less, the hydrocracking
catalyst further comprising 0.1 wt % to 5.0 wt % of a Group 8-10
noble metal supported on the hydrocracking catalyst, the
hydrocracking conditions comprising a hydrocracking reactor exit
temperature; dewaxing at least a portion of the hydrocracked
effluent and a recycled portion of a dewaxed effluent under
catalytic dewaxing conditions to form a dewaxed effluent, the
recycled portion of the dewaxed effluent optionally comprising 20
wt % to 50 wt % of the dewaxed effluent, the catalytic dewaxing
conditions comprising a dewaxing reactor inlet temperature that is
at least 20.degree. C. lower than the hydrocracking reactor exit
temperature, or at least 25.degree. C., or at least 30.degree. C.;
separating at least a portion of the dewaxed effluent to form at
least the recycled portion of the dewaxed effluent and a product
portion of the dewaxed effluent; and fractionating the product
portion of the dewaxed effluent to form at least a fuels boiling
range product and a lubricant boiling range product, wherein the
lubricant boiling range product has an aromatics content of 2.0 wt
% or less, or 1.5 wt % or less, or 1.0 wt % or less.
Embodiment 2
[0095] The method of Embodiment 1, further comprising
hydrofinishing at least a portion of the dewaxed effluent to form a
hydrofinished effluent, the separating at least a portion of the
dewaxed effluent comprising separating at least a portion of the
hydrofinished effluent.
Embodiment 3
[0096] The method of any of the above embodiments, wherein the
dewaxing reactor inlet temperature is less than 15.degree. C.
greater than a dewaxing weight average bed temperature, or less
than 10.degree. C. greater.
Embodiment 4
[0097] The method of any of the above embodiments, wherein
fractionating the product portion of the dewaxed effluent comprises
forming at least a first lubricant boiling range product and a
second lubricant boiling range product, the first lubricant boiling
range product having an aromatics content of 2.0 wt % or less, or
1.5 wt % or less, or 1.0 wt % or less, and the second lubricant
boiling range product having an aromatics content of 2.0 wt % or
less, or 1.5 wt % or less, or 1.0 wt % or less; and wherein the
first lubricant boiling range product optionally has a viscosity of
4 to 6 cSt, wherein the second lubricant boiling range product
optionally has a viscosity of 10-14 cSt, or a combination
thereof.
Embodiment 6
[0098] The method of any of the above embodiments, wherein the
feedstock comprises at least 40 wt % aromatics, or at least 50 wt
%.
Embodiment 7
[0099] The method of any of the above embodiments, wherein the
hydrocracking catalyst comprises a USY zeolite having one or more
(or two or more, or all) of a unit cell size of 24.24 .ANG. or
less, a silica to alumina ratio of at least 85, and an Alpha value
of 10 or less, the USY zeolite optionally comprising a Meso-Y
zeolite, an Extra Mesoporous Y zeolite, or a combination
thereof.
Embodiment 8
[0100] The method of any of the above embodiments, wherein
hydroprocessing the feedstock comprising exposing the feedstock to
a hydrotreating catalyst under hydrotreating conditions, or wherein
hydroprocessing the feedstock comprises exposing the feedstock to a
second hydrocracking catalyst under second hydrocracking
conditions, or a combination thereof.
Embodiment 9
[0101] A system for producing a lubricant boiling range product,
comprising: a hydrotreating reactor comprising a hydrotreating feed
inlet, a hydrotreating effluent outlet, and at least one fixed
catalyst bed comprising a hydrotreating catalyst; a separation
stage having a first separation stage inlet and a second separation
stage inlet, the first separation stage inlet being in fluid
communication with the hydrotreating effluent outlet, the
separation stage further comprising a plurality of separation stage
liquid effluent outlets, one or more of the separation stage liquid
effluent outlets corresponding to product outlets; a hydrocracking
reactor comprising a hydrocracking feed inlet, a hydrocracking
effluent outlet, and at least one fixed catalyst bed comprising a
hydrocracking catalyst, the hydrocracking feed inlet being in fluid
communication with at least one separation stage liquid effluent
outlet, and the hydrocracking catalyst comprising USY zeolite
having a unit cell size of 24.30 .ANG. or less, a silica to alumina
ratio of at least 50, and an Alpha value of 20 or less, the
hydrocracking catalyst further comprising 0.1 wt % to 5.0 wt % of a
Group 8-10 noble metal supported on the hydrocracking catalyst; and
a dewaxing reactor comprising a dewaxing feed inlet, a dewaxing
effluent outlet, and at least one fixed catalyst bed comprising a
dewaxing catalyst, the dewaxing feed inlet being in fluid
communication with the hydrocracking effluent outlet and being in
fluid communication with the dewaxing effluent outlet.
Embodiment 10
[0102] The system of Embodiment 9, wherein the dewaxing reactor
further comprises a fixed bed comprising a hydrofinishing catalyst,
wherein the hydrotreating reactor further comprises a fixed bed
comprising a hydrocracking catalyst, or a combination thereof.
Embodiment 11
[0103] The system of Embodiment 9 or 10, further comprising a
hydrofinishing reactor comprising a hydrofinishing feed inlet, a
hydrofinishing effluent outlet, and at least one fixed catalyst bed
comprising a hydrofinishing catalyst, the hydrofinishing feed inlet
being in direct fluid communication with the dewaxing feed outlet,
the dewaxing feed inlet being in direct fluid communication with
the hydrofinishing effluent outlet and in indirect fluid
communication with the dewaxing effluent outlet.
Embodiment 12
[0104] The system of any of Embodiments 9 to 11, the system further
comprising an additional hydrocracking reactor comprising an
additional hydrocracking feed inlet, an additional hydrocracking
effluent outlet, and at least one fixed catalyst bed comprising an
additional hydrocracking catalyst, the additional hydrocracking
reactor providing indirect fluid communication between the
hydrotreating effluent outlet and the first separation stage inlet,
the additional hydrocracking feed inlet being in fluid
communication with the hydrotreating effluent outlet, the
additional hydrocracking effluent outlet being in fluid
communication with the first separation stage inlet.
[0105] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the invention
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the invention. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present invention, including all features which
would be treated as equivalents thereof by those skilled in the art
to which the invention pertains.
[0106] The present invention has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims.
* * * * *