CA2194975A1

CA2194975A1 - Lubricating oil production with vi-selective catalyst

Info

Publication number: CA2194975A1
Application number: CA002194975A
Authority: CA
Inventors: James N. Ziemer
Original assignee: Individual
Current assignee: Chevron USA Inc
Priority date: 1994-08-01
Filing date: 1995-06-20
Publication date: 1996-02-15
Also published as: HU218039B; EP0775184B1; HUT77419A; PL318267A1; ATE281504T1; CZ4397A3; EP0775184A1; FI970395A0; PL179172B1; RU2140966C1; AU692574B2; SK10697A3; DE69533716T3; EP0775184A4; DE69533716T2; KR970704859A; CN1046544C; FI970395A; EP0775184B2; BR9508454A

Abstract

A process is provided for producing a high quality lubricating oil base stock with a catalyst having a high viscosity index selectivity and low fouling rate. The catalyst contains a low amount of zeolite, and has a pore size distribution characterized by a significant amount of large pores.

Description

WO 96/04354 P~,1/lJ.................................... r ~ 18 LUBRICATING OIL PRODUCTION WITH Vl-SELECTIVE CATALYST
R~ IINI) OF T~F INVFNTTON
Field af the Invention The present invention relates to a process for l,ydLvuL~cking a hydror~rhnnAreo~c feed to make a lubricating oil base stock. In particular, the process of this invention relates to a catalytic hydLv~L~cking process wherein the catalyst system exhibits surpri6ing stability and high viscosity index (VI) selectivity.

The catalyst of the present invention comprises a catalyst having a small amount of zeolite in an amorphous inorganic oxide matrix and containing a hydLuu~lation _~u-.~-lL. The catalyst is further characterized as having a significant amount of large pores. In the present process, a hydLvu~Lb~ reouc feed is upgraded by reaction over the catalyst system, so that sulfur, nitrogen and aromatic ~ _ L6 are removed, and the viscosity index of the lubricating oil base stock is increased relative to that of the feed. The catalyst system also exhibits a high VI selectivity. VI
selectivity is a relative measure of the increase in viscosity index during upgrading of a hydrocarbnnAreo feed. A high VI selectivity is indicative of a large increase in viscosity index for a given degree of conversion of the feed. The r~rt; nn~ involved in upgrading the hydLv~lb Ireou~ feed according to the present process are generally termed hydLv~L~cking.

Because feeds used in producing lubricating oil base stocks boil up to 1000~F (538~C.) and above, and contain relatively high nitrogen and sulfur levels, conventional hydrocracking catalysts typically foul quickly. In order to _ ~Le for this high fouling rate, zeolites may be added to the catalysts to increase both activity and stability. However, conventional zeolite-containing W096/04354 2l q4975 I~l/U~ 6 18 hydrocracking catalysts used for upgrading feeds in the preparation of lubes typically have low VI selectivity.

The present invention is; based on the discovery of a 5 catalyst containing zeo]ite and having a pore ~L~U~UL~
not generally found in 3ube hydrocracking catalysts which provides both improved s;tability and improved VI
selectivity for the catallyst system.

The pore size distribution of catalysts for l-ylluLL~ting heavy oil feedstocks rnn~;n;ng metals, particularly residuum feed~Lo~, have been r3;crlos~d in U.S. Patents Nos. 4,066,574; 4,113,661; and 4,341,625, hereinafter referred to as Tamm '574~, Tamm '661, and Tamm '625, and in U.S. Patent Nos. 5,1~7,047 and 5,215,955, hereinafter referred to as Threlkel '047 and Threlkel ~955. Tamm's patents disclose that hiavy oil fre~tor~c cnnt~;n;nrJ
metals, particularly res;iduum feedstocks, are l,~lLvle~ulfurized using a catalyst prepared by 20 i ~ Ling Group VIB amd Group VIII metals or metal ' into a 6upport comprising alumina wherein the support has at least 70~ of its pore volume in pores having a diameter between 80 and 150 ~. Threlkel '047 teaches that ~ LU~Lb~.l feedstocks rnnt~;n;ng metals 25 are h~l~ude~ulfurized usiling a catalyst prepared by ~..ating Group VIB and Group VIII metals or metal _ into a support comprising alumina wherein the support has at least 70~ of its pore volume in pores having a diameter between 70 and 130 ~, with less than 5S
30 of the pore volume being in pores having a diameter above 300 A and less than 2~ of the pore volume being in pores having a diameter above 1000 ~. Threlkel '955 teaches that hylLv~LLull feedstocks cnnt~;n;ng metals are hydrodesulfurized using a catalyst prepared by 35 ; _y..uLing Group VIB and Group VIII metals or metal - into a support comprising alumina wherein the support has at least 70% of its pore volume in pores ~ ~1 94~75 W096/043~4 r~ 6 ~ -3-having a diameter between 110 and 190 A, with less than 5% of the pore volume being in pores having a diameter above 500 A and less than 2~ of the pore volume being in pores having a diameter above lO00 A.
~
~ Johnson, in ~.S. Patent No. 5,089,463, dicrlo5~c a dehylL. L lAtion and hylLude~ulfurization process using a catalyst comprising a hylLu~llation _ L
selected from Group VI and~Group VIII metals, and an inorganic oxide refractory support, and wherein the catalyst has 5 to ll percent of its pore volume in the form of macropores, and a surface area greater than 75 m2/g of catalyst.

U.S. Patent No. 4,699,707 d;crlr--- that a full-range boiling shale or fraction thereof is LylLuLL~Led using a catalyst having a surface area in the range of 150 to 175 m2/g and a mean pore diameter between 75 and 85 ~nyDLL-and n pore size distribution such that nt least 75 percent of the pores are in the range of 60 to 100 ~Iy :, ~L ~

U.S. Patent No. 4,695,365 dicrl~c~c that n spindle oil is ~ylLuLLaaLed using a catalyst having a surface area of at least 100 m2/gm and a mean pore diameter between about 75 and 90 ~ny~LL. and a pore size distribution wherein at least 70 percent of the pore volume is in pores of diameter in the range from about 20 nlly~LL- below to 20 mly~LL. above the mean pore diameter.
~.S. Patent No. 5,171,422 d;cclnsPc a lube hydrocracking process using a zeolite of the faujasite ~LLu~LuL~
pnc~ g a LL ULk silica:alumina ratio of at least ~ about 50:1.
While these patents generally teach the usefulness of modifying the pore structure of catalysts for treating W096/0435~ 2 1 9 4 q 7 5 ~ i8 heavy oils, they do not address the Gpecific problems of achieviny high VI selectivity and improved catalyst stability in the l.ydL~ ing of a feed to produce a lubricating oil base stock.

~ of the Invention According to the present invention, a process is provided ~or producing 2 lubricating oil base stock which compri6es contacting under hydrocracking conditions a L~ reo~ feed with a catalyst comprising a zeolite, a l-~dL~..ation _ L and an inorganic oxide matrix material, the catalyst having a pore volume in the range of between about 0.25 and about 0.60 cm3/g, with a mean pore diameter between about 40 A and a~out 100 ~, with at least about 5% of the pore volume being in pores having a diameter of greater than about 200 A.

Among other factors, the present invention is based on the discovery that a cal:alyst containing a small amount of zeolite, and having a pore size distribution characterized by a high density of pores having diameters less than 100 A, and al~;o-high density of pores having ~ greater than about 200 ~, has improved VI
selectivity and improved organonitrogen removal activity over conventional hydrocracking catalysts in lube hydrocracking service. Furthermore, the catalyst of this invention has a lower fouling rate than that of conventional catalysts.

P.RTRF L ~:C~ ~1 I'Ll~N QF I~TF FIGIT~R.C

Figure 1 is a VI selectivity plot of catalysts of this invention compared with catalysts having pore size di6tributions outside the range of the catalyst of this invention.

~ 2 1 94 9 7~
W096/043s4 ~I/rJ~ _ 16 I~T~ TT.T~'n ~ r ~ I v,,lON OF 'I'T~T' lNV ~ ol~

Those familiar with the art related to the present invention will appreciate the full scope of the catalyst system and the process summarized above and be able to practice the present invention over its full scope from a de8cription of the principal features of the catalyst system and process which follows.

The discovery of the present process is embodied in a process for producing lubricating oil base stocks comprising hydrocracking a hydr?r~rh~n~r~ollc feed using a catalyst having a low amount of a zeolite _ _ and a pore ~LLU~U~e with a high density of pores having a ~i~ in the region of 40 ~ to 100 ~ and also having a high density of pores having a diameter above about 200 A.

The h~ l- Ar~ouc feeds from which lube oils are made usually contain aromatic _ as well as normal and hr~nrh~d paraffins of very long chain lengths. These feeds usually boil in the gas oil range. P.~C~...l fe _o~s are vacuum gas oils with normal boiling ranges in the range of 350~C. to 590~C., and deasphalted residual oils having normal boiling ranges from about 480~C. to 650~C. Reduced topped crude oils, shale oils, liquified coal, coke distillates, flask or thermally cracked oils, ~; ,hcric residua, and other heavy oils can also be used. In general, preferred feedstocks are 11~1L~LL~ AreOUC mixtures boiling above 200~C. ~nd are in the range of about 225~C. to 650~C.

In commercial operations, hydrocracking can take place as a single step process, or as a multi-step process using initial denitrification or desulfurization steps. The hy~ L~ing step of the invention may be conducted by contacting the feed with a fixed stationary bed of : .

W096/04354 2 ~ 949 75 r~ 6 catalyst, with a fixed fluidized bed, or with a transport bed. A simple and therefore preferred configuration is a trickle-bed operation in which the feed is allowed to trickle through a stationary fixed bed, preferably in the presence of hydrogen. Where the hydrorArhrn~r~o-lc feedstock has a high nitrogen or sulfur content, it is preferable to have a ~eLL~ai L stage to remove some portion of the nitrogen or sulfur. With the ~L~LLe~i L, the hydrc~cracking catalyst is able to operate more efficiently with a longer operating period than on high nitrogen or sulfur feed6. Normal hydrocracking ~Lo~s6eE. will then 6ubstantially eliminate any residual sulfur or nitrogen. Generally, a h~dlu~LL~ll feedstock used in hydrocracking should also have a low metals content, e.g~, less than about 200 ppm, in order to avoid obaLIu~Lion of the catalyst and plugging of the catalyEit bed.

P~Lthough the catalyst used in this method exhibits ~Yc~llrnt stability, ac:tivity and VI selectivity, reaction conditionsi mus;t nevertheless be carefully selected to provide the desired conversion rate while minimi~;ng conversion t:o less desired lower-boiling ,u ~du~L~. The conditions recluired to meet these objectives will depend on catalyst activity and selectivity and feedstock ~ha-~LcListics such as boiling rnnge, as well as organonitrogen and aromatic content and ~LLUULUL~. While react:ion onn~ifinnc depend on the most judicious _ I ice o~ overall activity, i.e., conversion and selectivity, it is one feature of the present invention that selectivity remains high, even at high conversion, and that conversion to less desired lower-boiling products is minimized in the production of the lubricating oil bas;e stock.
Selectivity as it relat:es to hy~LuuLau~ing to make a lubricating oil base st.ock refers to the magnitude of the 2~ 94975 W096/04354 F~~ 9_1 HS

~. y --7--increa6e in the viscosity index (VI) of the hyd~u~LL- ~c~ c feed as a result of hydrocracking. At a given extent of conversion of the feed, a high selectivity refers to a large increase in viscosity index during hydrocracking. Progressively lower selectivities indicate smaller increases in viscosity index, at a constant extent of conversion. The high VI selectivity of the catalyst used in this process results in a high lube yield during hydrocracking.
Typically, hydL~ essing conditions include a t~ _ ~LUL~ in the range of 400~F. ~204~C.) to 950~F.
(510~C.), a ~Les~uLe in the range of 500 to 3500 psig (3550 to 24200 RPa abs), a li~uid hourly space velocity in the range 0.1 to 20.0, and a total hydrogen supply in the range of 200 to 20,000 SCF of hydrogen per barrel of LydL~aLL ~eo~C feed (43-4300 std l Hl/kg feed).
Employing the foregoing l.~dL~L~cking conditions, conversion of feedstock to hydrocrackate product can be made to come within the range of from about lO to about 80 weight percent. However, higher conversion rates ge~nerally result in lower selectivity and greater amount of light, rather than middle distillate or lube boiling range, pL~du~L~. m us, a ~ _ ice must be drawn between conversion and selectivity, and conversions in the region of about 10 to about 70 percent are preferred.
m e hAlAn~ing of reaction conditions to achieve the desired objectives is part of the ordinary skill of the art. As used herein, conversion is that fraction of feed boiling above a target t~ UL~ which is converted to ~L~du~L~ boiling below that t _ ~LUL~. Generally, the target t _ ~LULe is taken as roughly the minimum of the boiling range of the feed.

m e catalyst used in the present invention has a pore ~ ~LL~UL~ which enhances the performance of the catalyst for hydLo~L~hing to produce a lubricating oil base .

W096/04354 21 94 9 75 r~

stock, ;n~lna;ng a pore volume in the range of between about 0.25 and about 0.60 cm3/g, preferably between about 0.25 and about 0.45 cm3,/g, with a mean pore diameter between about 40 A and about 100 A, preferably between about 40 A and about 80 A, and with at least about 5 percent, preferably at least about 10 percent and more preferably at least about 15 percent of the pore volume being in pores having a diameter of greater than about 200 A, preferably greater than about 350 A. In a separate preferred : i :, the catalyst has a pore volume with at leaGt about 1 percent of the pore volume being in pores having a diameter of greater than 1000 A.
As used herein, "mean pore diameter", refers to the point on a plot of cumulative pore volume vercus pore diameter 15 that co. ~ d~ to 50~ of the total pore volume of the catalyst as measured by mercury porosimetry or nitrogen physisorption porosimetry.

The catalyst used in the hydrocracking process comprises a large pore ~ nncilicate zeolite. Such zeolites are well known in the art, and include, for example, zeolites such as X, Y, ultrastable Y, dealuminated Y, faujasite, ZSM-12, ZSM-18, L, morde~ite, beta, offretite, ssZ-24, SSZ-25, SSZ-26, SSZ-31, SSZ-33, SSZ-35 and SSZ-37, SAPO-5, SAPO-31, SAPO-36, SAPO-40, SAPO-41 and VPI-5. Large pore zeolites are generally l ~nt i ~ as those zeolites having 12-ring pore openings. W.M. Meier and D.H. Olson, "ATLAS OF ZEOLITE ~L~aC~ TYPES", 3rd Edition, Butterworth-~ nn, 1992, identify and list examples of suitable zeolites.

One of the zeolites which is considered to be a good starting material for the manufacture of hydrocracking catnlysts is the well-known synthetic zeolite Y as described in U.S. Patent 3,130,007 issued April 21, 1964.
A number of modifications to this material have been reported, one of which is ultrastable Y zeolite as ~ W096/04354 ~l 9 4 9 75 r~l~u~ i8 described in U.s. Patent 3,536,605 lssued October 27, 1970. To further enhance the utility of synthetic Y
zeolite additional _ ~f L~ can be added. For example, U.S. Patent 3,835,027 issued on September 10, 1974 to Ward et al. describes a hydrocracking catalysts containing at least one ~h~u~ refractory oxide, a crystalline zeolitic aluminosilicate and a l,ylL~ge..d-ion : L selected from the Group VI and Group VIII
metals and their sulfides and their oxides. ~irker, et al., in U.S. Patent No. 5,171,422, disclose a d~A~ inAted Y zeolite for lube hydrocracking.

The p ef~led zeolite in the process of the present invention is one having a faujasite ~L~Lure, such as zeolite y, ultrastable zeolite Y and ~Aln~in~ted zeolite Y. In order to optimize the generally conflicting objectives of low catalyst fouling rate and high VI
selectivity of the catalyst, the catalyst generally contains less than about 20~, preferably less than about 10~, and more preferably less than about 8~, and still more preferably in the range of about 2 to about 6l zeolite on a volatiles-free basis. While within the broadest : '; L a wide variety of zeolites are suitable for the h~lLo~L~klng process, the pre~erred zeolite has low to moderate overall acidity, typically ith a siO2/Al2O3 molar rAtio in the range of about 5 to about 100, more preferably in the range of about 10 to about 60. Though it is believed that lube yield is not ~iqnific~ntly af~ected by the use of a low SiO2/Al203 ratio zeolite, low valued, low boiling products tend to be produced during hydrocracking at high conversions with a low SiO2/Al2O3 ratio zeolite. Using a zeolite having a higher siO2/Al2O3 ratio tends to product a non-lube fraction having a higher boiling point.
~ The hy~L~y_,~tion ~_ L may be at least one noble metal and/or at least one non-noble metal. 5uitable 21 9497~1 WO 96/0435~ r ~ C ~ 1~

noble metals include pLatinum, p~ Ail,m and other members of the platinum group such as iridium and ruthenium. Suitable non-noble metals include those of Groups VA, VIA, and VIIIA of the Periodic Table.
Preferred non-noble metals are chromium, molybdenum, tungsten, cobalt and nickel and combinations of these metals such as nickel-l:ungsten. Non-noble metal , ' F can be pre-sulfided prior to use by exposure to a sulfur-containing ga6 such as hydrogen sulfide at elevated tr _ ~LUL~ to convert the oxide form of the metal to the ~VLL ~...Ainq sulfide form.

The l.ydL~y~ Lion ~ _ L can be in~L~LaLe~ into the catalyst by any suitabLe method such as by ngl i ng during a mixing step, Iny i ~y..ation or by exchange.
The metal can be in~Ll,~L~ted in the form of a cationic, anionic or neutral complex; Pt(N~3~42l and cationic _1~Y~C of this type will be found convenient for exchanging metals onto the zeolite. Anionic ~ Y~C
such as heptamolybdate or LaLu,.yDLcte ions are alco useful for i ~y..aLing metals into the catalysts. One or more active sources of the l.y~L~y~ Lion _ - L may also be blended with t]le zeolite and active source of the silica~ min~lm matrix material during preparation of the catalyst. Active sources of the l~ydL~y~ Lion _ L
include, for example, ~my material having a form which is not detrimental to the catalyst and which will produce the desired lly~L~y~ Ling c _ L during preparation, ln~]llA;ng any drying " ~1 ~ining and reducing steps of the catalyst. Typical sallts which may be used as sources of the hydrogenation _ ~ include the nitrates, acetates, sulfates, chLorides.

The amount of hydl~y~ tion _ L can range from about 0.01 to about 45 percent by weight and is normally from about 0.1 to about 35 percent by weight. The precise amount will, oE course, vary with the nature of the ~- , less of the highly active noble metals, particularly platinum, being required than of the less active base metals. In this application, the term "noble ~ metal" includes one or more of ruthenium, rhodium, p~ inm, osmium, iridium or platinum. The term "base metal" includes one or more of Groups VB, VI3 and VIII
metals, inrln~in7, for example, vanadium, chromium, molybdenum, tungsten, iron, cobalt, and nickel. Usually a combination of base metals are used, such as the Group VIII metals nickel or cobalt in combination with the Group VIB metals tungsten or molybdenum, and the base metal is usually sulfided or presulfided in the catalyst when or before the catalyst is put on stream. A
preferred catalyst for the present process contains in the range from about 1 to about 15% by weight, and preferably from about 2 to about 10% by weight of at least one Group VIII base metal, calculated as the metal ~ , and in the range from about 5 to about 30% by weight, and preferably from about 10 to about 25S by weight of at least one Group VIB metal, calculated as the metal trioxide.

The zeolite can be composited with porous inorganic oxide matrix materials and mixtures of matrix materials such as silica, alumina, silica-alumina, titania, r~gn~1A, sili~ , silica-zirconia, silica-thoria, silica-beryllia, silica-titania, titania-zirconia, as well as ternary compositions such as silica-alumina-thoria, silica-alumina-titania, silica-alumina _ ;A and silica ~ -zirconia. The matrix can be in the form of a cogel. A preferred support material to facilitate catalyst preparation and improve catalyst physical properties is an alumina support. ~ven more preferred is a zeolite composited with a silica alumina matrix material, with at least 1% additional alumina binder.
When the zeolite is composited with one or more inorganic oxide matrix material(s) to make the catalyst, the 21 9497~ ~
W096/04354 P~

catalyst comprises ~rom about 30 to about 90 weight percent, more pre~erably from about 45 to about 75 weight percent of the inorganic oxide matrix material. Silica alumina matrix materials useful in the catalyst of this process generally have a silica/alumina mole ratio in the range of between about 10/90 and 90/10, preferably in the range of between about 20/80 and 80/20, and more preferably in the range of between about 25/75 and 75/25.
Ground catalyst which contains hydL~y~ tion metals and has n~ ;n~lly. the same composition as the catalyst of the l.ydL~L~_~ing process may be used as a source of the inorganic oxide matrix material. It is preferred that the inorganic oxide matrix materials used in preparing the catalyst be finely ~yround to a particle size of 50 microns or less, more preferably to a particle size of 30 microns or less, and still more preferably to a particle size of 10 microns or less.

The zeolite may also be composited with inactive materials, which suitably serve as diluents to control the amount of conversion in the hydrocracking process so that products can be obtained e c~lly without employing other means for controlling the rate of reaction. Naturally ocrurring clays which can be composited with the catalyst include the ~ n;te and kaolin families, which families include the sub-bentonites, and the kaolins commonly known as Dixie, ~cNamee, Georgia and Florida clays or others in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite. ~ibrous clays such as halloysite, sepiolite amd attapulgite can also be used as supports. Such clays c~n be used in the raw state as originally mined or initially subjected to calcination, acid Ll~a or chemical modification. When used in the present process, the catalyst will generally be in the form of tablets, pellets, extrudates, or any other form which is useful in the particular process.

~ 21 94975 W096/04354 r~ 18 During ~L~ Lion of the catalyst of the present process, the zeolite, and sources of the inorganic matrix material are combined with sufficient water to give a volatilefi content of the mix of between 40 and 60 weight percent, more preferably between 45 and 55 weight percent. This mix i5 then formed into a desired shape, and the shaped particles thermally treated to form the catalyst. The term "volatiles" as used herein is the material evolved during the high tl, ~LUL~ (2 900~F. [2 482~C]) drying. The shape of the catalyst depends on the specific application and process conditions of the hydrorr~r~;nr~ process inr~ ;nrJ but not limited to tablets, pellets, ~L~ud~Les, or any other form which i6 useful in the particular process. The l,yd~u~..ation metals may be included by adding active sources of the metals to the mix prior to shaping and heating.
Alternatively, the Ly~L~..ation metals may be added after the shaping and/or heating steps, using methods known to the art, such as by i ~eyl.ation.
The overall conversion rate is primarily controlled by reaction f', ~LUL~3 and liquid hourly space velocity, in order to achieve the desired VI of the product. The process can be operated as a single-stage IIYdLV~LUCe ~ing zone having a catalyst system comprising the Lyd~u~L~_hing catalyst of the present process. It can also be operated as a layered catalyst system having at least two catalyst layers, with the lube hydLuuru~king catalyst of the present process converting a hyd~v~--L ~re~ ~ feed stream which was previously treated in a first h~dlu~u.lv~L~ion catalyst layer. In a layered catalyst system, the first l.ydlu~ul-v~L~ion layer performs some cracking and removes nitrogen and sulfur from the feedstock before contact with the lube hydrocracking catalyst. Preferably, the organonitrogen content of the product leaving the top layer of catalyst is less than 500 ppm, more preferably less than 250 ppm, W096/04354 2194975 -14- r~ cr 1~ -and still more preferably less than 100 ppm. The top layer of catalyst will generally comprise a hydLucu~ LDion catalyst comprising Group Vl and/or Group VIII hydLu4e~Lion _ - on a silica or silica-alumina support. Preferred hydLugellation for the hydLu~ Ling catalyst include nickel, molybdenum, tungsten and cobalt or a combination thereof. An active zeolite, such as a Y-tylpe zeolite, and preferably an active Y-type zeolite having a SiO~/Al203 of less than about 10, may be included with the hYdLOCUIIV L~ion catalyst in order to im:rease activity and catalyst stability. The relativla amounts of catalyst used in the various catalyst layers is specific to each reactor system and ffedDLL~a~ u~ed, dop~n~;ng on, for example, the severity of the operating conditions, the boiling range of the feed, the ~uantity of heteroatoms such as nitrogen and sulfur in the feed, and the desired lubricating oil base stock properties. Typically, in a catalyst system comprising a i.y~LuC~ aion catalyst layer and a lube hydrocracking catalyst layer, the volumetric ratio of h~d.ùcull~_L~ion catalyst to LydLu~L~cking catalyst :is in the range between about 1/99 and about 99/1, preferably between about 10/90 and about 50/50.
~LU~UIl~ ~ Dion reaction conditions in the hydLu~u-v~LDion catalysl: layer may be the same as or different from conditions in the hydrocracking layer.
Generally, hydL~cu.lv~L~iion conditions include a t~ _ ~Lu.a in the range of 400~F. (204~C.) to 950~F.
(510~C.), a pressure in the range of 500 to 3500 psig (3550 to 24200 ~Pa ab&), a liquid hourly space velocity in the range 0.1 to 20.0, and a total hydrogen supply in the range of 200 to 20,000 SCF of hydrogen per barrel of h~dLU~L1J~ C feed ~43-4300 std 1 H2/kg feed).

W096l043s4 ~ . i&
~ -15-The lubricating oil base stock produced by the present hydrocracking proces6 will have a high viscosity index, a low nitrogen content and a low sulfur content. Prior to additional processing, it may be distilled into two or more fractions of varying boiling points, with each fraction being characterized by a particular viscosity index value and a particular nitrogen and a particular ~ulfur content. Generally, at least one of the fractions will have a viscosity index greater than about 85 and preferably greater than about go. ~owever, the viscosity index can be as high as 125 or even 130, ~r~n~;ns on the fesd~Lo~ being treated. While methods are available for ~ rminin~ the visc08ity index of a waxy stock, the viscosity index values given here are based on lubricating oil base stocks which have been solvent dewaxed, using methods well known in the art, to a -lO~C.
pour point.

The catalyst of the present process also removes a ~ub~La..Lial portion of the organonitrogen and organosulfur _ - from the L~IL~ - --A- ~----- feed.
These reactions removing heteroatom _ ~ are 1 _ ~allL, as organonitrogen, and to a lesser extent organosulfur _ , are detrimental to LL~am processing of the lubricating oil base stock, such as dewaxing and hydrofinishing. Products of the h~L~L~at removal reactions, such as ammonia and hydrogen sulfide, are signif;cAntly less detrimental to these ~ LL~am ~L o~sse4 . The nitrogen and sulfur contents of the lubricating oil base stooks, or at least one of the distillate fractions derived from the lubricating oil base stock, will typically be less than 25 ppm, usually less than 10 ppm, and levels as low as l ppm or less are often observed. Indeed, it is an i LallL
oharacteristic of the catalyst of this prooess that nitrogen - are ~ L Led to ammonia at much higher reaction rates, and to much larger extent, than . ., .. - , 1., W096/04354 2 1 94975 . ~ 5,~

catalysts used in conve!ntional lube hydrocracking ~1 vC~::iaeS .

The lubricating oil base stock produced by the hydrocracking step may be dewaxed following hydrocracking. Dewaxirlg may be ~ hP~ by one or more yLuce~es known to the art, inrln~;ng solvent dewaxing or catalytic cLewaxing. Zeolites such as ZSM-5, ZSM-ll, ZSM-12, ZSM-23, ZSM-35 and ZSM-38 have been proposed for this purpose in dewaxing y.ùue~ses and their use is described in U.S. Patent Nos. 3,700,585;

3,894,938; 4,176,050; 4,181,598; 4,222,855; 4,229,282 and 4,247,388. Zeolite SSZ-32 and dewaxing ~.v~ses using ssz-32 are described in U.S. Patent Nos. 5,053,373 and 5,252,527, the ~;crlosll-es of which are incuL~u.~ed herein by reference. ~AP0-11 and dewaxing ~Lu~se5 using SAP0-11 are described in U.S. Patent No. 4,859,311, the ~icrlocllre of which, is incorporated herein by ~~f~.ce.
Dewaxing is typically Cnn~rtP~ at t- _ ~Lu~5 ranging from about 200~C. to about 475~C. at ~L~s~u.es from about 15 psig (205 RPa abs) to~about 3000 psig (20800 RPa abs) at space velocities (L~SV) between about 0.1 and 20 and at hydrogen recycle rates of 500 to 30,000 SCF~bbl (107-6400 std 1 H2/kg oil fe,ed). The dewaxing catalyst may include a hyL-uyellation ~, particularly the Group VIII metals such as cobalt, nickel, p~ ; and platinum.
It is often desirable to use mild hyd~v~e~Lion (sometimes referred to as hydrofinishing) to produce more stable lubricating oils. The hydrofinishing step can be performed either before or after the dewaxing step, and pre~erably after. Hydro~inishing is typically conducted at t~ ~u~s ranging from about 190~C. to about 340~C.
at ~ u.~ from about 400 psig (2860 RPa abs) to about ~ 2~ 94q75 W096/04354 ~ 18 3000 psig (20800 RPa abs) at space velocities (LHSV~
between about 0.1 and 20 and at hydrogen recycle rates of 400 to 1500 SCF/bbl (86-320 std 1 H2/kg oil feed). The hydlvyel,aLion catalyst employed must be active enough not S only to hydLvye~aLe the olefins, diolefins and color bodies within the lube oil fractions, but also to reduce the aromatic content. The hydrofinishing step is beneficial in preparing an acceptably stable lubricating oil since lubri Q nt oils prepared from hydrocracked stocks tend to be unstable to air and light and tend to form sludges ~ Lallevu~ly and ~uickly.

Sl~;tAhl~ hyd~y_.lation catalysts include conventional ~ ll;r. L~dl~y_.l~-ion catalygts, particularly the Group VIII metals such as cobalt, nickel, p~llAAi and platinum. The metal is typically associated with carriers such as bauxite alumina, silica gel, silica-alumina composites, and crystalline aluminosilicate zeolites pAll~Ai i8 a particularly ~LereLLed hydl~yellation metal. If desired, non-noble Group VIII
metals can be used. Metal oxides or sulfides can be used. Suitable c~talysts are detailed, for instance, in U.S. Patent Nos. 3,852,207; 4,157,294; 3,904,513 and 4,673,487, all of which are in~ L~Led herein by reference.

These and other specific applications of the catalyst and process of the present invention are illustrated in the following examples.
~XAMPLES

Example 1 A nickel/nitric acid solution was prepared by dissolving - 142.4 grams of Ni(No3)2-6H2o in 120 cc of A~in~1~ed water and carefully mixing with 10.3 g of 70% nitric acid.

W096/04354 ~ ,S~

204.13 g ~ L~ly~L~Le was dissolved in 220 cc of deionized water. The pH of the solution was 2.70.

107.8 (volatiles free) g Plural alumina, 28.8 g (volatiles free) of PG/Conte~a CBV-760 ultrasta le Y
zeolite with a silica/alumina mole ratio of 62, and 363.4 g (volatiles free) Siral 40 (Condea: 40/60 sio2/Al2o3) powder was combined an a small BP mixer and mixed for five minutes. The jacket t -LULC7 of the mixer was maintained at 140-160~F. (60~C-71~C.) while 133 cc of d~inn; 7ed water was slowly added. After 3 minutes mixing, the nickel/nitric acid solution was added by spraying into the material in the mixer. After three minutes the in~ ~.yDL~te solution was added, and the mixing cnntin~ for an additional 7 minutes.
This mixture was then f~Dund to have a pH of 4.07 and a volatiles content of 49.8~.

The mixture was then extruded, and the extrudates placed l inch deep (2.5 cm) in a screen tray and dried at 320~F.
(160~C.) for one hour. The dried extrudate were then heated to 950~F over a 1.5 hour period and held at 950~F.
(510~C.) for one hour in 2 scf/hour (0.057 m3/hr) of flowing dry air.
EYample 2 A nickel/nitric acid solution was prepared by dissolving 156.9 grams of Ni(NO3)2-6H2O in 120 cc of ~7~inni7~r7~ water and carefully mixing with 10.3 g of 70% nitric acid.

178.8 g; ;llm ' L~,.yDL~Le was dissolved in 220 cc of ~7.~inn7 7C-7. water. The pH of the solution was 2.77.

105 g (volatiles-free) Catapal B alumina (Engelhard), 35.0 g (volatiles-free) of CBV-500 ultrastable Y zeolite (PQ/Conteka) ground to a nominal particle size of 2 1~ 21 94~75 W096/04354 ~ IO
~ ~ --19--microns and having a silica/alumina mole ratio of 5.7, ~nd 290.0 g (volatiles-free) Siral 40 (Condea: 40/60 ~iO2/Al203) powder was combined an a small BP mixer and ~ixed for five minutes. The jacket I IL~L~ of the mixer was r~;ntAin~d at 140-160~F. (60~C-71~C.) while 125 cc of r'~i~n;7Qd water was slowly added. After 3 minutes mixing, the nickel/nitric acid solution was added by spraying into the material in the mixer. After five minutes of additional mixing, the ; ; L~-y~L~Le Eolllti-7n was added, and the miYing c~n~;n~ for ~n -~r~.7t;nn~1 5 minutes. 70.0 g (volatiles-free) of a commercial nickel/tlln7Qten/silica/alumina l,~dL~LL~Ling catalyst, having approximately the same ~
composition as the catalyst being prepared in this example, and ground to a nominal particle size of less than 10 microns was then slowly added, and the mixture mixed an additional 9 minutes. m e mixture was then found to have a pH of 4.35 and a volatiles content of 50.1%.
The mixture was then extruded, and the extrudates placed 1 inch (2.5 cm) deep in 2 screen tray and dried at 320~F.
(160~C.) for one hour. The dried extrudate were then heated to 950~F.(510~C.) over a 1.5 hour period and held at 950~F.(510~C.)for one hour in 2 scf/hour (0.057 m3/hr) of flowing dry air.

Properties of the catalysts are listed in the following table:
Catalyst Composition Ex. 1 Ex. 2 ~ 23.7 wt~ 23.3 wt%
.~ic'~el 3.84 wt~ 5.36 wt~
Silicon 10.9 wtS 10.5 wt%
Tungsten 19.7 wt%20.3 wt%

W096/04354 2 1 q 4 ~ 7 5 -20- r~

Pore volume by mercury porosimetry (ASTM D4284) Total: 0.3158 cm3/g 0.395 cm3/g Nacropore:0.0394 cm3/g0.0918 cm3/g Particle Density1.44 g/cm31.33 g/cm3 Example 3 Cat~lvst A
Catalysts of this invemtion were tested as follows. For each test a pilot plant reactor was charged with a layer of standard zeolite-containing LydLocYllv~L~ion catalyst and a layer of the hYdLY~ hing catalyst of this invention ~nnt~;ning 4~ zeolite (Catalyst A), in which the volume ratio of hyd~y~y-lv~L~ion catalyst/hydrocracking catalyst was roughly 1/2.

After pr~ lf;~;n7 the catalysts, they were tested with a standard vacuum gas oil feed at 2200 psig (15300 RPa abs) total pressure and 0.48 LHSV, with the t~ ~Lur~
controlled to achieve a target conversion. Products were fractionated, and the 650~F+ (343~C+) fraction solvent dewaxed and a viscosity index S~t~rm; n~ . Fig~tre 1 shows the results from testing a number of catalysts of this invention, with the data showing the viscosity index of the 650~F+ product as a function of extent of conversion.

Cat~lvst B ~ ~ ~
The test was repeated using a layered catalyst system with the standard zeolite-containing hydLY~YIlv~ion catalyst layered with a catalyst having the same pore size distribution as Catalyst A, and with 10% zeolite (Catalyst B). The VI selectivity data from this test, which is also included in Figure 1, is equal to that o~
the comparative Catalyst C ~described below).

21 9~975 W096/04354 ' ~'At~ vst C
The tefit was repeated using a layered catalyst system with the standard zeolite-c~n~Ain;ng l1YdL~C~I~V-L ion catalyst layered with a commercial non-zeolitic hydL~L~cking catalyst (Catalyst C). The data taken from this test, which is also included in Figure 1, shows that the VI selectivity of this catalyst was approximately 5 VI numbers lower than that of Catalyst A.

CatalYst D
The test was repeated using a layered catalyst system with the standard zeolite-containing hydL~c~llv~L~ion catalyst layered with a catalyst having a pore size distribution smaller than that Catalyst A, and with 10%
zeolite (Catalyst D). The data from this test, which is also included in Figure 1, shows that the VI selectivity was reduced even further when a cataly6t containing a larger ~mount of zeolite and having a pore size distribution outside the range of the catalyst of this invention was used.

There are numerous variations on the present invention which are possible in light of the l~rh;ng~ and examples supporting the present invention. It is therefore ~.~_L_~ood that within the scope of the following claims, the invention may be practiced otherwise than _s spe~;ficAlly described or exemplified herein.

Claims

WHAT IS CLAIMED IS:

1. A process for producing a lubricating oil base stock which comprises contacting under hydrocracking conditions a hydrocarbonaceous feed with a catalyst comprising a zeolite, a hydrogenation component and an inorganic oxide matrix material, the catalyst having a pore volume in the range of between about 0.25 and about 0.60 cm3/g, with a mean pore diameter between about 40 .ANG. and about 100 .ANG., with at least about 5% of the pore volume being in pores having a diameter of greater than about 200 .ANG..

2. The process according to Claim 1 wherein the mean pore diameter is between about 40 and about 80 .ANG..

3. The process according to Claim 1 wherein at least about 10% of the pore volume is in pores having a diameter greater than about 200 .ANG..

4. The process according to Claim 1 wherein at least about 15% of the pore volume is in pores having a diameter greater than about 200 .ANG..

5. The process according to Claim 4 wherein at least about 1% of the pore volume is in pores having a diameter greater than about 1000 .ANG..

6. The process according to Claim 1 wherein the zeolite is selected from zeolite Y, dealuminated zeolite Y
and ultrastable zeolite Y.

7. The process according to Claim 1 wherein the catalyst comprises from about 1 to about 20 percent by weight of the zeolite.

8. The process according to Claim 1 wherein the catalyst comprises from about 1 to about 10 percent by weight of the zeolite.

9. The process according to Claim 1 wherein the zeolite has a SiO2/Al2O3 molar ratio in the range of between about 5 and about 100.

10. The process according to Claim 1 wherein the zeolite has a SiO2/Al2O3 molar ratio in the range of between about 5 and about 60.

11. The process according to Claim 1 wherein the catalyst contains from about 0.01 to about 45 percent by weight of the hydrogenation component.

12. The process according to Claim 11 wherein the hydrogenation component comprises from about 5% to about 30% by weight, calculated as the metal trioxide, of at least one Group VIB metal selected from tungsten, molybdenum and combinations thereof.

13. The process according to Claim 12 wherein the hydrogenation component comprises from about 1% to about 15% by weight, calculated as the metal monoxide, of at least one Group VIII base metal selected from nickel, cobalt and combinations thereof.

14. The process according to Claim 1 wherein the catalyst contains from about 30 percent to about 90 percent by weight of the inorganic oxide matrix material.

15. The process according to Claim 1 wherein the inorganic oxide matrix material is selected from alumina, silica alumina and combinations thereof.

16. The process according to Claim 1 wherein the hydrocarbonaceous feed is a vacuum gas oil having a normal boiling range in the range of about 350°C. to 590°C.

17. The process according to Claim 1 wherein the hydrocarbonaceous feed is a deasphalted residual oil having a normal boiling range in the range of about 480°C. to 650°C.

18. The process according to Claim 1 wherein the hydrocracking conditions include a temperature in the range of 400°F. (204°C.) to 950°F. (510°C.), a pressure in the range of 500 to 3500 psig (3550 to 24200 KPa abs), a liquid hourly space velocity in the range 0.1 to 20.0, and a total hydrogen supply in the range of 200 to 20,000 SCF of hydrogen per barrel of hydrocarbonaceous feed (43-4300 std 1 H2/kg feed).

19. The process according to Claim 1 providing a conversion from about 10 to about 80 weight percent.

20. A process according to Claim 1 wherein a 650°F.
(343°C.) + fraction of the lubricating oil base stock is subjected to dewaxing, hydrofinishing, or a combination thereof.

21. The process according to Claim 20 wherein the dewaxing is carried out under catalytic dewaxing or solvent dewaxing conditions.

22. A process for producing a lubricating oil base stock which comprises contacting under hydrocracking conditions a hydrocarbonaceous feed with a catalyst comprising:

a. from about 1 to about 10 % by weight of a zeolite having a faujasite structure;

b. from about 1 to about 15% by weight, calculated as the metal monoxide, of at least one Group VIII metal selected from nickel, cobalt and combinations thereof, and from about 5 to about 30% by weight, calculated as the metal trioxide, of at least one Group VIB metal selected from tungsten, molybdenum and combinations thereof; and c. from about 45 to about 75% by weight of an amorphous silica-alumina matrix material; and d. sufficient alumina support material to make 100% by weight;

wherein the catalyst has a pore volume in the range of between about 0.25 and about 0.45 cm3/g, with a mean pore diameter between about 40 .ANG. and about 100 .ANG., and with at least about 5% of the pore volume being in pores having a diameter of greater than about 200 .ANG.., and wherein the hydrocarbonaceous feed is a vacuum gas oil having a normal boiling range in the range of about 350°C. to 590°C.

23. A process for producing a lubricating oil base stock comprising:

n. contacting a hydrocarbonaceous feed under hydroconversion conditions with a hydroconversion catalyst to produce a hydrotreated product having a nitrogen content of less than 100 ppm; and b. contacting the hydrotreated product under hydrocracking conditions with a catalyst comprising a zeolite having a faujasite structure, a hydrogenation component, and a silica-alumina matrix material, the catalyst having a pore volume in the range of between about 0.25 and about 0.60 cm3/g, with a mean pore diameter between about 40 .ANG. and about 100 .ANG., with at least about 5% of the pore volume being in pores having a diameter of greater than about 200 .ANG..