AU1718999A - Dewaxing process - Google Patents

Description

WO 99/29810 PCT/US98/26112 -1 1 DEWAXING PROCESS 2 3 I. FIELD OF THE INVENTION 4 5 The present invention relates to a process for catalytically dewaxing lube oils. 6 More specifically, the invention relates to a process for dewaxing a 7 hydrocarbon oil feedstock wherein at least a portion of fractionator bottoms is 8 recycled to the feedstock. 9 10 II. BACKGROUND OF THE INVENTION 11 12 Certain processes for dewaxing petroleum distillates are well known. 13 Dewaxing is required when highly paraffinic oils are to be used in products 14 which must be mobile at low temperatures, e.g., lubricating oils, heating oils, 15 and jet fuels. The higher molecular weight straight chain normal, substituted 16 and slightly branched paraffins present in such oils are waxes that cause high 17 pour points and high cloud points in the oils. If adequately low pour points 18 are to be obtained, the waxes must be wholly or partially removed. In the 19 past, various solvent removal techniques were employed to remove such 20 waxes, such as propane dewaxing and MEK dewaxing; however, these have 21 high operating costs, significant environmental impacts and produce oils 22 which are inferior to catalytically-dewaxed oils. Catalytic dewaxing processes 23 are more economical and remove the waxes by selectively isomerizing and 24 cracking paraffinic components to produce lower molecular weight products, 25 some of which may be removed by distillation. 26 27 Because of their selectivity, known dewaxing catalysts generally comprise an 28 aluminosilicate zeolite having a pore size which admits the straight chain 29 n-paraffins either alone or with only slightly branched chain paraffins, but 30 which excludes more highly branched materials, larger cycloaliphatics and WO 99/29810 PCT/US98/26112 -2 1 aromatics. Zeolites such as ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35 and 2 ZSM-38 have been proposed for this purpose in dewaxing processes. Their 3 use is described in U.S. Pat. Nos. 3,700,585; 3,894,938; 4,176,050; 4 4,181,598; 4,222,855; 4,229,282 and 4,247,388, the disclosures of which are 5 incorporated herein by reference. 6 7 Since many dewaxing processes of this kind function by means of cracking 8 reactions, a number of useful products become degraded to lower molecular 9 weight materials. For example, waxy paraffins may be cracked down to 10 butane, propane, ethane and methane and so may the lighter n-paraffins 11 which do not contribute to the waxy nature of the oil. Because these lighter 12 products are generally of lower value than the higher molecular weight 13 materials, it is desirable to limit the degree of cracking which takes place 14 during a catalytic dewaxing process. 15 16 European Patent Application No. 225,053 discloses a process for producing 17 lubricant oils by partially dewaxing a lubricant base stock by isomerization 18 dewaxing followed by a selective dewaxing step. The isomerization dewaxing 19 step is carried out using a large pore, high silica zeolite dewaxing catalyst 20 such as high silica Y or zeolite beta which isomerizes the waxy components 21 of the base stock to less waxy branched chain isoparaffins. The selective 22 dewaxing step may be either a solvent, e.g., MEK dewaxing operation or a 23 catalytic dewaxing, preferably using a highly shape zeolite such as ZSM-22 or 24 ZSM-23. 25 26 U.S. Pat. No. 4,437,976 discloses a two-stage hydrocarbon dewaxing 27 hydrotreating process wherein the pour point of a hydrocarbon charge stock 28 boiling from 400°F to 1050 0 F is reduced by catalytically dewaxing the charge 29 stock in the presence of a zeolite catalyst and subsequently subjecting at 30 least the liquid portion thereof to hydrogenation in the presence of a WO 99/29810 PCT/US98/26112 -3 1 hydrotreating catalyst comprising a hydrogenating component and a siliceous 2 porous crystalline material from the class of ZSM-5, ZSM-11, ZSM-23 and 3 ZSM-35 zeolites. 4 5 U.S. Pat. No. 4,575,416 to Chester et al. discloses a hydrodewaxing process 6 with a first zeolitic catalyst having a Constraint Index not less than 1, a 7 second catalytic component of specified characteristics and a hydrogenation 8 component. 9 10 U.S. Pat. No. 5,149,421 teaches a dewaxing catalyst which provides superior 11 selectivity with respect to the nature of the products obtained in a dewaxing 12 process. By using an intermediate pore size silicoaluminophosphate 13 molecular sieve catalyst in the dewaxing process, hydrocarbon oil feedstocks 14 are effectively dewaxed and the products obtained are of higher molecular 15 weight than those obtained using the other aluminosilicate zeolites. The 16 products obtained from the dewaxing process have better viscosities and 17 viscosity indexes at a given pour point as compared to the above-described 18 prior art process using aluminosilicate zeolites. 19 20 Nevertheless, it would be advantageous to have a process which provided 21 increased yield over the yield obtained in known processes, or increased pour 22 point reduction at the same yield. The present invention provides such a 23 process. 24 25 III. SUMMARY OF THE INVENTION 26 27 The present invention overcomes the problems and disadvantages of the 28 prior art by providing a process for catalytically dewaxing a hydrocarbon oil 29 feedstock which produces a superior lube oil yield. 30 WO 99/29810 PCT/US98/26112 -4 1 The process of the invention for converting a hydrocarbon oil includes the 2 following steps: (1) contacting a hydrocarbon oil feedstock in the presence of 3 added hydrogen gas with a catalyst selected from the group consisting of a 4 SAPO-11, SAPO-31 or SAPO-41 intermediate pore size 5 silicoaluminophosphate molecular sieve and a hydrogenation component, and 6 mixtures thereof, where at least a portion of the feedstock is converted; and 7 (2) passing at least a portion of the converted feedstock to a fractionator, 8 where at least a portion of the converted feedstock is fractionated, thus 9 producing at least one overhead fraction and one bottoms fraction; and 10 (3) mixing at least a portion of the bottoms fraction with the hydrocarbon oil 11 feedstock in step (1). 12 13 IV. BRIEF DESCRIPTION OF THE DRAWING 14 15 Figure 1 depicts a simplified schematic flow chart of one embodiment of the 16 process of the invention. 17 18 V. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 19 20 A. Steps of the Process 21 22 The process of the invention for converting a hydrocarbon oil includes the 23 following steps: (1) contacting a hydrocarbon oil feedstock in the presence of 24 added hydrogen gas with a catalyst system containing catalyst selected from 25 the group consisting of a SAPO-11, SAPO-31 or SAPO-41 intermediate pore 26 size silicoaluminophosphate molecular sieve and a hydrogenation 27 component, and mixtures thereof, where at least a portion of the feedstock is 28 converted; and (2) passing at least a portion of the converted feedstock to a 29 fractionator, where at least a portion of the converted feedstock is 30 fractionated, thus producing at least one overhead fraction and one bottoms WO 99/29810 PCT/US98/26112 -5 1 fraction; and (3) mixing at least a portion of the bottoms fraction with the 2 hydrocarbon oil feedstock in step (1). 3 The catalyst system optionally further includes a catalyst selected from the 4 group consisting of an intermediate pore size aluminosilicate zeolite catalyst, 5 an amorphous catalyst, and mixtures thereof. For pre-treatments, the feed 6 may be hydrocracked or solvent extracted and hydrotreated. This type of 7 process and typical hydrocracking conditions are described in U.S. Patent 8 No. 4,921,594, issued May 1, 1990 to Miller, which is incorporated herein by 9 reference in its entirety. Post-treatments can include hydrofinishing, 10 discussed below. 11 Without being limited by theory, in one embodiment, the dewaxing 12 mechanism is isomerization and/or cracking of waxy compounds. Typically, 13 catalytic dewaxing, e.g., Chevron's ISODEWAXING catalytic dewaxing 14 process, operates to improve the pour point and viscosity index of a 15 feedstock, compared to solvent dewaxing. 16 B. Feedstock 17 18 The process of the invention may be used to dewax a variety of hydrocarbon 19 oil feedstocks classified generally as any waxy hydrocarbon feed, lube oil 20 feedstock, or middle distillate oil. The feedstocks include distillate fractions, 21 e.g., hydrocrackates, up to high boiling stocks such as deasphalted and 22 solvent extracted oils. The feedstock will normally be a C 1 0 + feedstock 23 generally boiling above about 350 0 F, since lighter oils will usually be free of 24 significant quantities of waxy components. However, the process is 25 particularly useful with waxy distillate stocks such as middle distillate stocks 26 including gas oils, kerosenes, and jet fuels, lubricating oil stocks, heating oils 27 and other distillate fractions whose pour point and viscosity need to be WO 99/29810 PCT/US98/26112 -6 1 maintained within certain specification limits. Lubricating oil stocks will 2 generally boil above 2300C (450 0 F), more usually above 315 0 C (600 0 F). 3 Hydroprocessed stocks are a convenient source of stocks of this kind and 4 also of other distillate fractions since they have a higher hydrogen content 5 over solvent-processed stocks and are usually relatively free of heteroatoms 6 (e.g., sulfur and nitrogen compounds) which can impair the performance of 7 the dewaxing and hydrofinishing catalysts. The feedstock of the present 8 process will normally be a C10+ feedstock containing paraffins, olefins, 9 naphthenes, aromatics and heterocyclic compounds and a substantial 10 proportion of higher molecular weight n-paraffins and slightly branched and 11 substituted paraffins which contribute to the waxy nature of the feedstock. 12 During processing, feed molecules undergo some cracking or hydrocracking 13 to form liquid range materials which contribute to a low viscosity product. The 14 degree of cracking which occurs is, however, limited to preserve the yield of 15 the valuable liquids. 16 Typical feedstocks include light gas oils, heavy gas oils and reduced crudes 17 boiling above 350 0 F. In one embodiment, the feedstock contains a major 18 portion of a hydrocarbon oil feedstock boiling above about 350 0 F and 19 contains straight chain and slightly branched chain hydrocarbons. The term 20 "major portion" means more than 50 weight percent. 21 While the process of the invention can be practiced with utility when the feed 22 contains organic nitrogen (nitrogen-containing impurities), it is preferred that 23 the organic nitrogen content of the feed be less than 50 ppmw, more 24 preferably less than 10 ppmw. Particularly good results, in terms of activity 25 and length of catalyst cycle (period between successive regenerations or 26 startup and first regeneration), are experienced when the feed contains less 27 than 10 ppmw of organic nitrogen.

WO 99/29810 PCT/US98/26112 -7 1 C. Silicoaluminophosphate Molecular Sieve Catalyst Compositions 2 1. Generally: 3 Intermediate pore size silicoaluminophosphate molecular sieves (SAPOs) are 4 catalysts used in the process of the invention. Suitable SAPOs are any 5 conventional intermediate pore SAPO. The SAPOs are used separately or in 6 combination with zeolites and/or amorphous catalysts. Examples of 7 silicoaluminophosphate molecular sieves which can used in this invention are 8 described in U.S. Pat. Nos. 4,440,871 and 5,149,421, the disclosures of 9 which are incorporated herein by reference. 10 The intermediate pore size silicoaluminophosphate molecular sieve catalyst is 11 employed in the process of the invention to convert the waxy components to 12 non-waxy components and reduce their pour point by about 30 0 F to about 13 60 0 F. The amount of catalyst employed is dependent on the reaction 14 conditions. 15 In a preferred embodiment, the final catalyst will be a composite and includes 16 an intermediate pore size silicoaluminophosphate molecular sieve, a platinum 17 or palladium hydrogenation metal component and an inorganic oxide matrix. 18 The preferred intermediate pore size silicoaluminophosphate molecular 19 sieves suitable for use in the process of this invention include SAPO-11, 20 SAPO-31 and SAPO-41. The most preferred silicoaluminophosphate is 21 SAPO-11, the most preferred metal component is platinum, and the most 22 preferred binder is alumina. Descriptions of SAPO-11, SAPO-31 and 23 SAPO-41 and methods of making them are given in the above referenced 24 patents and in R. Szostak, Handbook of Molecular Sieves (Van Norstrand 25 Reinhold 1992), pages 410-413, 415-416, 419-420, the disclosures of which 26 are incorporated herein by reference.

WO 99/29810 PCT/US98/26112 -8 1 2. Special Preparations: 2 The molecular sieve can be composited with other materials resistant to the 3 temperatures and other conditions employed in the dewaxing process. Such 4 matrix materials include active and inactive materials and synthetic or 5 naturally occurring zeolites as well as inorganic materials such as clays, silica 6 and metal oxides. The latter may be either naturally occurring or in the form 7 of gelatinous precipitates, sols or gels including mixtures of silica and metal 8 oxides. Inactive materials suitably serve as binders or as diluents to control 9 the amount of conversion in the dewaxing process so that products can be 10 obtained economically without employing other means for controlling the rate 11 of reaction. 12 The silicoaluminophosphates may be combined with naturally occurring clays, 13 e.g., bentonite and kaolin. These materials, i.e., clays, oxides, etc., function, 14 in part, as binders for the catalyst. It is desirable to provide a catalyst having 15 good crush strength because in petroleum refining the catalyst is often 16 subjected to rough handling and large forces in the reactor. This tends to 17 break the catalyst down into fragments which can plug the reactor. 18 Naturally occurring clays which can be composited with the 19 silicoaluminophosphate include the montmorillonite and kaolin families, which 20 families include the sub-bentonites, and the kaolins commonly known as 21 Dixie, McNamee, Georgia and Florida clays or others in which the main 22 mineral constituent is halloysite, kaolinite, dickite, nacrite, or anauxite. 23 Fibrous clays such as halloysite, sepiolite and attapulgite can also be used as 24 supports. Such clays can be used in the raw state as originally mined or 25 initially subjected to calcination, acid treatment or chemical modification. 26 In addition to the foregoing materials, the silicoaluminophosphates can be 27 composited with porous matrix materials, e.g., inorganic oxide matrix, and WO 99/29810 PCT/US98/26112 -9 1 mixtures of matrix materials such as silica, alumina, titania, magnesia, silica 2 alumina, silica-magnesia, silica-zirconia, silica-thoria, silica-beryllia, silica 3 titania, titania-zirconia as well as ternary compositions such as silica-alumina 4 thoria, silica-alumina-titania, silica-alumina-magnesia and silica-magnesia 5 zirconia. The matrix can be in the form of a cogel or an intimate physical 6 mixture. 7 8 The silicoaluminophosphate catalysts used in the process of this invention 9 can also be composited with other zeolites such as synthetic and natural 10 faujasites, (e.g., X and Y) erionites and mordenites. They can also be 11 composited with purely synthetic zeolites such as those of the ZSM series. 12 The combination of the zeolites can also be composited in a porous inorganic 13 matrix. 14 D. Zeolites 15 Exemplary suitable aluminosilicate zeolite catalysts for use in the process of 16 the invention include ZSM-22, ZSM-23 and ZSM-35. These are taught in 17 R. Szostak, Handbook of Molecular Sieves (Van Norstrand Reinhold 1992), at 18 pages 538-542 and 545-546, which are incorporated herein by reference, and 19 in U.S. Patent Nos. 4,481,177; 4,076,842; and 4,016,245, the disclosures of 20 which are incorporated herein by reference. 21 22 The silicoaluminophosphate molecular sieve catalyst and the aluminosilicate 23 zeolite catalyst are employed in the process of the invention in an effective 24 weight ratio of the intermediate pore size silicoaluminophosphate molecular 25 sieve to the intermediate pore size aluminosilicate zeolite molecular sieve to 26 increase yield of converted feedstock. Preferred ratios are from about 1:5 to 27 about 20:1. The zeolite used in the process preferably has a Constraint Index 28 measured at from about 400 0 C to about 4540C of from about 4 to about 12. 29 WO 99/29810 PCT/US98/26112 -10 1 In another embodiment of the process of the invention, SSZ-48, preferably 2 predominantly in the hydrogen form, can be used in the dewaxing process of 3 the invention. Without being limited by theory, SSZ-48 is believed to dewax 4 by selectively removing straight chain paraffins. Typically, the viscosity index 5 of the dewaxed product is improved (compared to the solvent dewaxed feed) 6 when the waxy feed is contacted with SSZ-48 under isomerization dewaxing 7 (also referred to as hydrodewaxing) conditions. 8 9 In preparing SSZ-48 zeolites, a decahydroquinolinium cation is used as a 10 crystallization template. The decahydroquinolinium cation may have the 11 following structure: CO 12

CH

3

CH

2

CH

2

CH

3 13 The anion (X-) associated with the cation may be any anion which is not 14 detrimental to the formation of the zeolite. Representative anions include 15 halogen, e.g., fluoride, chloride, bromide and iodide, hydroxide, acetate, 16 sulfate, tetrafluoroborate, carboxylate, and the like. Hydroxide is the most 17 preferred anion. 18 In general, SSZ-48 is prepared by contacting an active source of one or more 19 oxides selected from the group consisting of monovalent element oxides, 20 divalent element oxides, trivalent element oxides, and tetravalent element 21 oxides with the decahydroquinolinium cation templating agent. 22 SSZ-48 is prepared from a reaction mixture having the composition shown in 23 Table 1 below.

WO 99/29810 PCT/US98/26112 -11 1 TABLE 1 2 Reaction Mixture 3 Typical Preferred 4 YO2/WaOb 10 - 100 15 - 40 5 OH-/YO 2 0.10 - 0.50 0.20 -0.30 6 Q/YO 2 0.05 - 0.50 0.10 - 0.20 7 M 2 /n/YO 2 0.01 - 0.10 0.03 - 0.07 8 H 2 0/YO 2 20 - 80 30 -45 9 wherein Y is silicon, germanium or a mixture thereof; W is aluminum, gallium, 10 iron, boron, titanium, indium, vanadium or mixtures thereof; c is 1 or 2; d is 2 11 when c is 1 (i.e., W is tetravalent) or d is 3 or 5 when c is 2 (i.e., d is 3 when 12 W is trivalent or 5 when W is pentavalent); M is an alkali metal cation, alkaline 13 earth metal cation or mixtures thereof; n is the valence of M (i.e., 1 or 2); and 14 Q is at least one decahydroquinolinium cation, and a is 1 or 2, and b is 2 15 when a is 1 (i.e., W is tetravalent) and b is 3 when a is 2 (i.e., W is trivalent). 16 In practice, SSZ-48 is prepared by a process comprising: 17 (a) preparing an aqueous solution containing sources of at least one 18 oxide capable of forming a crystalline molecular sieve and a 19 decahydroquinolinium cation having an anionic counterion which is 20 not detrimental to the formation of SSZ-48; 21 (b) maintaining the aqueous solution under conditions sufficient to 22 form crystals of SSZ-48; and 23 (c) recovering the crystals of SSZ-48. 24 Accordingly, SSZ-48 may comprise the crystalline material and the templating 25 agent in combination with metallic and non-metallic oxides bonded in 26 tetrahedral coordination through shared oxygen atoms to form a cross-linked 27 three dimensional crystal structure. The metallic and non-metallic oxides WO 99/29810 PCT/US98/26112 -12 1 comprise one or a combination of oxides of a first tetravalent element(s), and 2 one or a combination of a second tetravalent element(s) different from the first 3 tetravalent element(s), trivalent element(s), pentavalent element(s) or mixture 4 thereof. The first tetravalent element(s) is preferably selected from the group 5 consisting of silicon, germanium and combinations thereof. More preferably, 6 the first tetravalent element is silicon. The second tetravalent element (which 7 is different from the first tetravalent element), trivalent element and 8 pentavalent element is preferably selected from the group consisting of 9 aluminum, gallium, iron, boron, titanium, indium, vanadium and combinations 10 thereof. More preferably, the second trivalent or tetravalent element is 11 aluminum or boron. 12 Typical sources of aluminum oxide for the reaction mixture include 13 aluminates, alumina, aluminum colloids, aluminum oxide coated on silica sol, 14 hydrated alumina gels such as AI(OH) 3 and aluminum compounds such as 15 AIC 3 and Al 2 (SO4) 3 . Typical sources of silicon oxide include silicates, silica 16 hydrogel, silicic acid, fumed silica, colloidal silica, tetra-alkyl orthosilicates, 17 and silica hydroxides. Boron, as well as gallium, germanium, titanium, 18 indium, vanadium and iron, can be added in forms corresponding to their 19 aluminum and silicon counterparts. 20 A source zeolite reagent may provide a source of aluminum or boron. In most 21 cases, the source zeolite also provides a source of silica. The source zeolite 22 in its dealuminated or deboronated form may also be used as a source of 23 silica, with additional silicon added using, for example, the conventional 24 sources listed above. Use of a source zeolite reagent as a source of alumina 25 for the present process is more completely described in U.S. Patent 26 No. 5,187,132, issued February 16, 1993 to Zones et al. entitled "Preparation 27 of Borosilicate Zeolites", the disclosure of which is incorporated herein by 28 reference.

WO 99/29810 PCT/US98/26112 -13 1 Typically, an alkali metal hydroxide and/or an alkaline earth metal hydroxide, 2 such as the hydroxide of sodium, potassium, lithium, cesium, rubidium, 3 calcium, and magnesium, is used in the reaction mixture; however, this 4 component can be omitted so long as the equivalent basicity is maintained. 5 The templating agent may be used to provide hydroxide ion. Thus, it may be 6 beneficial to ion exchange, for example, the halide for hydroxide ion, thereby 7 reducing or eliminating the alkali metal hydroxide quantity required. The alkali 8 metal cation or alkaline earth cation may be part of the as-synthesized 9 crystalline oxide material, in order to balance valence electron charges 10 therein. 11 The reaction mixture is maintained at an elevated temperature until the 12 crystals of the SSZ-48 zeolite are formed. The hydrothermal crystallization is 13 usually conducted under autogenous pressure, at a temperature between 14 1000C and 2000C, preferably between 1350C and 160 0 C. The crystallization 15 period is typically greater than 1 day and preferably from about 3 days to 16 about 20 days. 17 Preferably, the zeolite is prepared using mild stirring or agitation. 18 During the hydrothermal crystallization step, the SSZ-48 crystals can be 19 allowed to nucleate spontaneously from the reaction mixture. The use of 20 SSZ-48 crystals as seed material can be advantageous in decreasing the 21 time necessary for complete crystallization to occur. In addition, seeding can 22 lead to an increased purity of the product obtained by promoting the 23 nucleation and/or formation of SSZ-48 over any undesired phases. When 24 used as seeds, SSZ-48 crystals are added in an amount between 0.1 and 25 10% of the weight of silica used in the reaction mixture. 26 Once the zeolite crystals have formed, the solid product is separated from the 27 reaction mixture by standard mechanical separation techniques such as 28 filtration. The crystals are water-washed and then dried, e.g., at 900C to WO 99/29810 PCT/US98/26112 -14 1 1500C for from 8 to 24 hours, to obtain the as-synthesized SSZ-48 zeolite 2 crystals. The drying step can be performed at atmospheric pressure or under 3 vacuum. 4 SSZ-48, as prepared, has a mole ratio of an oxide selected from silicon oxide, 5 germanium oxide and mixtures thereof to an oxide selected from aluminum 6 oxide, gallium oxide, iron oxide, boron oxide, titanium oxide, indium oxide, 7 vanadium oxide and mixtures thereof greater than about 40; and has the 8 X-ray diffraction lines of Table 2 below. 9 TABLE2 10 As-Synthesized SSZ-48 11 2 Theta(a) d Relative Intensity (b) 6.55 13.5 S 8.0 11.0 VS 9.4 9.40 M 11.3 7.82 M-W 20.05 4.42 VS 22.7 3.91 VS 24.1 3.69 VS 26.5 3.36 S 27.9 3.20 S 35.85 2.50 M 12 13 (a) + 0.3 14 (b) The X-ray patterns provided are based on a relative intensity 15 scale in which the strongest line in the X-ray pattern is assigned 16 a value of 100: W(weak) is less than 20; M(medium) is between 17 20 and 40; S(strong) is between 40 and 60; VS(very strong) is 18 greater than 60. 19 SSZ-48 further has a composition, as synthesized and in the anhydrous state, 20 in terms of mole ratios, shown in Table 3 below.

WO 99/29810 PCT/US98/26112 -15 1 TABLE 3 2 As-Synthesized SSZ-48 3 YO 2 WcOd 40 - 100 4 M2/n/YO2 0.01 - 0.03 5 Q/YO 2 0.02 - 0.05 6 7 wherein Y is silicon, germanium or a mixture thereof; W is aluminum, gallium, 8 iron, boron, titanium, indium, vanadium or mixtures thereof; c is 1 or 2; d is 2 9 when c is 1 (i.e., W is tetravalent) or d is 3 or 5 when c is 2 (i.e., d is 3 when 10 W is trivalent or 5 when W is pentavalent); M is an alkali metal cation, alkaline 11 earth metal cation or mixtures thereof; n is the valence of M (i.e., 1 or 2); and 12 Q is at least one decahydroquinolinium cation. 13 A method of increasing the mole ratio of silica to boron is by using standard 14 acid leaching or chelating treatments. Lower silica to alumina ratios may also 15 be obtained by using methods which insert aluminum into the crystalline 16 framework. For example, aluminum insertion may occur by thermal treatment 17 of the zeolite in combination with an alumina binder or dissolved source of 18 alumina. Such procedures are described in U.S. Patent No. 4,559,315, 19 issued on December 17, 1985 to Chang et al, the disclosure of which is 20 incorporated herein by reference. 21 SSZ-48 zeolites, as-synthesized, have a crystalline structure whose X-ray 22 powder diffraction pattern exhibit the characteristic lines shown in Table 2 23 above and is thereby distinguished from other known zeolites. 24 After calcination, the SSZ-48 zeolites have a crystalline structure whose X-ray 25 powder diffraction pattern include the characteristic lines shown in Table 4: WO 99/29810 PCT/US98/26112 -16 1 TABLE 4 2 Calcined SSZ-48 2 Theta(a) d Relative Intensity (b) 6.55 13.5 VS 8.0 11.0 VS 9.4 9.40 S 11.3 7.82 M 20.05 4.42 M 22.7 3.91 M 24.1 3.69 M 26.5 3.36 M 27.9 3.20 W 35.85 2.50 W 3 4 (a) + 0.3 5 The X-ray powder diffraction patterns were determined by standard 6 techniques. The radiation was the K-alpha/doublet of copper. The peak 7 heights and the positions, as a function of 20 where 0 is the Bragg angle, 8 were read from the relative intensities of the peaks, and d, the interplanar 9 spacing in Angstroms corresponding to the recorded lines, can be calculated. 10 The variation in the scattering angle (two theta) measurements, due to 11 instrument error and to differences between individual samples, is estimated 12 at ±0.30 degrees. 13 The X-ray diffraction pattern of Table 2 above is representative of 14 "as-synthesized" or "as-made" SSZ-48 zeolites. Minor variations in the 15 diffraction pattern can result from variations in the silica-to-alumina or 16 silica-to-boron mole ratio of the particular sample due to changes in lattice 17 constants. In addition, sufficiently small crystals will affect the shape and 18 intensity of peaks, leading to significant peak broadening.

WO 99/29810 PCT/US98/26112 -17 1 Representative peaks from the X-ray diffraction pattern of calcined SSZ-48 2 are shown in Table 4. Calcination can also result in changes in the intensities 3 of the peaks as compared to patterns of the "as-made" material, as well as 4 minor shifts in the diffraction pattern. The zeolite produced by exchanging the 5 metal or other cations present in the zeolite with various other cations (such 6 as H or NH 4 ) yields essentially the same diffraction pattern, although again, 7 there may be minor shifts in the interplanar spacing and variations in the 8 relative intensities of the peaks. Notwithstanding these minor perturbations, 9 the basic crystal lattice remains unchanged by these treatments. 10 Crystalline SSZ-48 can be used as-synthesized, but preferably will be 11 thermally treated (calcined). Usually, it is desirable to remove the alkali metal 12 cation by ion exchange and replace it with hydrogen, ammonium, or any 13 desired metal ion. The zeolite can be leached with chelating agents, e.g., 14 EDTA or dilute acid solutions, to increase the silica to alumina mole ratio. 15 The zeolite can also be steamed; steaming helps stabilize the crystalline 16 lattice to attack from acids. 17 SSZ-48, and any other zeolite used in this process, can be used in intimate 18 combination with hydrogenating components, such as tungsten, vanadium 19 molybdenum, rhenium, nickel, cobalt, chromium, manganese, or a noble 20 metal, such as palladium or platinum, for those applications in which a 21 hydrogenation-dehydrogenation function is desired. Platinum and palladium 22 are preferred. 23 24 Metals may also be introduced into the zeolites by replacing some of the 25 cations in the zeolite with metal cations via standard ion exchange techniques 26 (see, for example, U.S. Patent Nos. 3,140,249 issued July 7, 1964 to Plank 27 et al.; 3,140,251 issued July 7, 1964 to Plank et al.; and 3,140,253 issued 28 July 7, 1964 to Plank et al., the disclosures of which are incorporated herein 29 by reference). Typical replacing cations can include metal cations, e.g., rare WO 99/29810 PCT/US98/26112 -18 1 earth, Group IA, Group IIA and Group VIII metals, as well as their mixtures. 2 Of the replacing metallic cations, cations of metals such as rare earth, Mn, 3 Ca, Mg, Zn, Cd, Pt, Pd, Ni, Co, Ti, AI, Sn, and Fe are particularly preferred. 4 The techniques of introducing catalytically active metals to a molecular sieve 5 are disclosed in the literature, and pre-existing metal incorporation techniques 6 and treatment of the molecular sieve to form an active catalyst such as ion 7 exchange, impregnation or occlusion during sieve preparation are suitable for 8 use in the present process. Such techniques are disclosed in U.S. Pat. 9 Nos. 3,236,761; 3,226,339; 3,236,762; 3,620,960; 3,373,109; 4,202,996; 10 4,440,781 and 4,710,485, the disclosures of which are incorporated herein by 11 reference. The amount of metal ranges from about 0.01% to about 10% by 12 weight of the zeolite, preferably from about 0.2% to about 5%. 13 The hydrogen, ammonium, and metal components can be ion-exchanged into 14 the zeolites. They can also be impregnated with the metals, or, the metals 15 can be physically and intimately admixed with the zeolite using standard 16 methods known to the art. 17 Typical ion-exchange techniques involve contacting the synthetic zeolite with 18 a solution containing a salt of the desired replacing cation or cations. 19 Although a wide variety of salts can be employed, chlorides and other halides, 20 acetates, nitrates, and sulfates are particularly preferred. The zeolite is 21 usually calcined prior to the ion-exchange procedure to remove the organic 22 matter present in the channels and on the surface, since this results in a more 23 effective ion exchange. Representative ion exchange techniques are 24 disclosed in a wide variety of patents including U.S. Patent Nos. 3,140,249 25 issued on July 7, 1964 to Plank et al.; 3,140,251 issued on July 7, 1964 to 26 Plank et al.; and 3,140,253 issued on July 7, 1964 to Plank et al, the 27 disclosures of which are incorporated herein by reference.

WO 99/29810 PCT/US98/26112 -19 1 Following contact with the salt solution of the desired replacing cation, the 2 zeolite is typically washed with water and dried at temperatures ranging from 3 650C to about 2000C. After washing, the zeolite can be calcined in air or inert 4 gas at temperatures ranging from about 2000C to about 8000C for periods of 5 time ranging from 1 to 48 hours, or more, to produce a catalytically active 6 product especially useful in hydrocarbon conversion processes. 7 Regardless of the cations present in the synthesized form of SSZ-48, the 8 spatial arrangement of the atoms which form the basic crystal lattice of the 9 zeolite remains essentially unchanged. 10 The hydrogenation component is present in an appropriate amount to provide 11 an effective hydrodewaxing and hydroisomerization catalyst preferably in the 12 range of from about 0.05 to 5% by weight. The catalyst may be run in such a 13 mode to increase isodewaxing at the expense of cracking reactions. 14 15 Any two or more zeolites utilized in this process may be utilized as a 16 dewaxing catalyst in the form of a layered catalyst. That is, the catalyst 17 comprises a first layer comprising, e.g., zeolite SSZ-48 and at least one 18 Group VIII metal, and a second layer comprising another aluminosilicate 19 zeolite, e.g., one which, optionally, is more shape selective than zeolite 20 SSZ-48. The use of layered catalysts is disclosed in U.S. Patent 21 No. 5,149,421, issued September 22, 1992 to Miller, which is incorporated by 22 reference herein in its entirety. The layering may also include a zeolite bed, 23 e.g., SSZ-48, layered with a non-zeolitic component designed for either 24 hydrocracking or hydrofinishing. Instead of layering, intimately mixed catalyst 25 systems represent another useful variant on this concept.

WO 99/29810 PCT/US98/26112 -20 1 E. Amorphous Catalysts 2 3 The amorphous catalysts useful in the invention are any amorphous catalysts 4 having hydrogenation and/or isomerization effects on the feedstock. Such 5 amorphous catalysts are taught, e.g., in U.S. Patent No. 4,383,913, the 6 disclosure of which is incorporated herein by reference. 7 These include, e.g., amorphous catalytic inorganic oxides, e.g., catalytically 8 active silica-aluminas, clays, synthetic or acid activated clays, silicas, 9 aluminas, silica-aluminas, silica-zirconias, silica-magnesias, alumina-borias, 10 alumina-titanias, pillared or cross-linked clays, and the like and mixtures 11 thereof. 12 F. Process Conditions 13 The process is conducted at catalytic dewaxing conditions. Such conditions 14 are known and are taught for example in U.S. Patent Nos. 5,591,322; 15 5,149,421; and 4,181,598, the disclosures of which are incorporated herein 16 by reference. The catalytic dewaxing conditions are dependent in large 17 measure on the feed used and upon the desired pour point. Hydrogen is 18 preferably present in the reaction zone during the catalytic dewaxing process. 19 The hydrogen to feed ratio, i.e., hydrogen circulation rate, is typically between 20 about 500 and about 30,000 SCF/bbl (standard cubic feet per barrel), 21 preferably about 1000 to about 20,000 SCF/bbl. Generally, hydrogen will be 22 separated from the product and recycled to the reaction zone. 23 24 The percent of fractionator bottoms recycled to the feed is an effective 25 amount to enhance overall yield. Preferably, the percent recycle is from 26 about 1 to about 100, or more preferably from about 10 to about 50. The ratio 27 of fractionator bottoms to the raw feed is an effective ratio to either reduce 28 pour point with no loss in yield or to enhance overall yield while maintaining WO 99/29810 PCT/US98/26112 -21 1 pour point. Preferably, the ratio is from about 1:100 to about 60:100, or more 2 preferably from about 1:100 to about 40:100. 3 An intermediate pore size aluminosilicate zeolite catalyst and/or amorphous 4 catalyst are optionally used in the same reactor as the 5 silicoaluminophosphate molecular sieve catalyst, or may be used in a 6 separate reactor. When two or more catalysts are used in the same reactor, 7 they may be sequentially layered or mixed. When sequentially layered, the 8 SAPO is optionally the first the first or second layer. When two or more 9 catalysts are used in the same reactor, they may also me intimately mixed. 10 Any conventional catalyst bed configuration can be used in the process of the 11 invention. 12 13 The catalytic isomerization step of the invention may be conducted by 14 contacting the feed to be dewaxed with a fixed stationary bed of catalyst, with 15 a fixed fluidized bed, or with a transport bed, as desired. A simple and 16 therefore preferred configuration is a trickle-bed operation in which the feed is 17 allowed to trickle through a stationary fixed bed, preferably in the presence of 18 hydrogen. 19 20 The catalytic dewaxing conditions employed depend on the feed used and 21 the desired pour point. Some generalizations of process conditions for 22 various catalytic processes are shown in Table 5 below: 23 WO 99/29810 PCT/US98/26112 -22 Table 5 Process Temp., oC Pressure LHSV Hydrocracking 175-485 0.5-350 bar 0.1-30 Dewaxing 200-475 15-3000 psig 0.1-20 (250-450) (200-3000) (0.2-10) Aromatics 400-600 atm.-10 bar 0.1-15 formation (480-550) Cat. cracking 127-885 subatm.-' 0.5-50 (atm.-5 atm.) Oligomerization 232-6492 0.1-50 atm.

2

,

3 0.2-502 10-2324 0.05-206 (27-204)4 - (0.1-10) 5 Paraffins to 100-700 0-1000 psig 0.5-405 aromatics Condensation of 260-538 0.5-1000 psig 0.5-505 alcohols Isomerization 93-538 50-1000 psig 1-10 (204-315) (1-4) Xylene 260-5932 0.5-50 atm.

2 0.1-1005 isomerization (315-566)2 (1-5 atm) 2 (0.5-50)5 38-3714 1-200 atm.

4 0.5-50 1 2 1 Several hundred atmospheres 3 2 Gas phase reaction 4 3 Hydrocarbon partial pressure 5 4 Liquid phase reaction 6 5 WHSV 7 8 In the process of this invention, generally, the temperature is from about 9 2000C and about 4750C, preferably between about 2500C and about 450 0 C. 10 The pressure is typically from about 15 psig and about 3000 psig, preferably 11 between about 200 psig and 3000 psig. The liquid hourly space velocity 12 (LHSV) preferably will be from 0.1 to 20, preferably between about 0.2 and 13 10. 14 15 Hydrogen is preferably present in the reaction zone during the catalytic 16 isomerization process. The hydrogen to feed ratio is typically between about WO 99/29810 PCT/US98/26112 -23 1 500 and about 30,000 SCF/bbl (standard cubic feet per barrel), preferably 2 from about 1000 to about 20,000 SCF/bbl. Generally, hydrogen will be 3 separated from the product and recycled to the reaction zone. 4 5 G. Post-Treatments 6 It is often desirable to use mild hydrogenation (sometimes referred to as 7 hydrofinishing). The hydrofinishing step is beneficial in preparing an 8 acceptably stable product (e.g., a lubricating oil) since unsaturated products 9 tend to be unstable to air and light and tend to degrade. The hydrofinishing 10 step can be performed after the isomerization step. Hydrofinishing is typically 11 conducted at temperatures ranging from about 1900C to about 3400C, at 12 pressures of from about 400 psig to about 3000 psig, at space velocities 13 (LHSV) of from about 0.1 to about 20, and hydrogen recycle rates of from 14 about 400 to about 1500 SCF/bbl. 15 The hydrogenation catalyst employed must be active enough not only to 16 hydrogenate the olefins and diolefins within the lube oil fractions, but also to 17 reduce the content of any aromatics present. 18 19 Suitable hydrogenation catalysts include conventional, metallic hydrogenation 20 catalysts, particularly the Group VIII metals such as cobalt, nickel, palladium 21 and platinum. The metals are typically associated with carriers such as 22 bauxite, alumina, silica gel, silica-alumina composites, and crystalline 23 aluminosilicate zeolites and other molecular sieves. Palladium is a 24 particularly preferred hydrogenation metal. If desired, non-noble Group VIII 25 metals can be used with molybdates. Metal oxides or sulfides can be used. 26 Suitable catalysts are disclosed in U.S. Pat. Nos. 3,852,207; 4,157,294; 27 4,921,594; 3,904,513 and 4,673,487, the disclosures of which are 28 incorporated herein by reference.

WO 99/29810 PCT/US98/26112 -24 1 VI. DETAILED DESCRIPTION OF THE DRAWING 2 Figure 1 depicts a simplified schematic flow chart of one embodiment of the 3 process of the invention. Lube oil feedstock stream 5 and hydrogen stream 4 10 are passed to catalytic dewaxing unit 15, e.g., an ISODEWAXING catalytic 5 dewaxing unit. The effluent 20 from catalytic dewaxing unit 15 is passed to 6 hydrofinishing unit 25. The effluent 30 from hydrofinishing unit 25 is passed 7 to atmospheric distillation column 35 for initial fractionation. Various product 8 streams, e.g., light gases stream 36, naphtha stream 37, jet fuel stream 38, 9 and bottoms stream 40, are removed from atmospheric distillation column 35. 10 Bottoms stream 40 from atmospheric distillation column 35 is passed to 11 vacuum distillation column 45 for further fractionation. Various product 12 streams, e.g., diesel fuel stream 50, 60 Neutral Oil stream 55, 100 Neutral Oil 13 stream 60, and bottoms stream (or 300 Neutral Oil) 65, are removed from 14 vacuum distillation column 45. A portion of bottoms stream 65 is removed as 15 300 Neutral Oil stream 70 and a portion is recycled through stream 75 to mix 16 with fresh lube oil feedstock stream 5. 17 VII. ILLUSTRATIVE EMBODIMENTS 18 19 The invention will be further clarified by the following examples, which are 20 intended to be purely exemplary of the invention. 21 22 * The benefits of fractionator bottoms recycle operation have been 23 demonstrated in large-scale pilot-plant testing. For the demonstration run, 24 the Isodewaxing reactor contained about 5,000 cc of a precious-metal 25 impregnated SAPO-11 catalyst and the hydrofinishing reactor contained 26 about 5,000 cc of a Chevron proprietary hydrofinishing catalyst. On-line 27 distillation produced 3 lube cuts plus a mid-distillate cut. The pilot plant 28 was configured to simulate the flow scheme illustrated in Figure 1. 29 WO 99/29810 PCT/US98/26112 -25 1 * Two broad-boiling hydrocracked feedstocks were tested. Inspections for 2 these feedstocks are shown in Table 6. Following Isodewaxing and 3 hydrofinishing, the whole liquid product was fractionated into 3 finished 4 base oil cuts - a 60 Neutral Oil, a 100 Neutral Oil and a 300 Neutral Oil. 5 Table 7 summarizes the performance improvements obtained by recycling 6 a portion of the fractionator bottoms. 7 8 * For Tests 1 through 4, the fresh feed rate was maintained approximately 9 constant, while the percent of fractionator bottoms recycle and the 10 Isodewaxer weighted average bed temperature (WAT) were varied. The 11 hydrofinisher was operated at approximately constant temperature during 12 these runs. 13 14 A. Comparing Test 1 and Test 2 shows that when recycling a large 15 proportion of the fractionator bottoms, it is possible to reduce the 16 Isodewaxer WAT and, although, the dewaxing severity is not quite the 17 same in both cases, dramatically increase the total lube yield - from 18 70% to 80%. Recycling also moved the pour points of the 100N and 19 the 300N much closer together - the difference between the pour 20 points is 18*C in Test 2, but only 90C in Test 1. This means that with 21 recycling, the 100N does not have to be overdewaxed as much to 22 make an acceptable pour point on the 300N. 23 B. Test 3 was run to the same 300N pour point as Test 2. With recycling 24 (Test 3), we were able to increase the overall lube yield by 3%, and 25 increase the yield of the low-pour point, high-value, 100N by 4%. Here 26 again, with recycling, the degree of overdewaxing of the 100N is 27 reduced. 28 C. Test 4 was run at the same Isodewaxer Weighted Average Bed 29 Temperature as Test 2, but in Test 4, the Isodewaxer feed contained 30 13 fractionator bottoms (recycle). Although the total lube yield is the WO 99/29810 PCT/US98/26112 -26 1 same, in Test 4, there is 2% less 300N and 2% more 60N. More 2 importantly, in Test 4, the pour points of the finished lube fractions are 3 substantially lower. Thus, recycling can improve the product properties 4 of the finished lubes without changing the overall yield. 5 6 * For Tests 5 through 7, the fresh feed rate, as well as the percent of 7 fractionator were varied. Here again, the hydrofinisher was operated at 8 approximately constant temperature. 9 10 A. For Test 6, the fresh feed rate was increased by 23% without any 11 recycling. To maintain the same approximate pour point on the 300N, 12 the Isodewaxer WAT had to be increased by 5 0 F, but in this case 13 (without recycling), the total lube yield remained the same, while the 14 pour points of the lube fractions increased slightly (got worse). 15 B. For Test 7, the fresh feed rate was essentially maintained and the 16 Isodewaxer feed contained 14% fractionator bottoms. In this case, we 17 were able to lower the Isodewaxer catalyst temperature slightly, while 18 maintaining close to the same product pour points, and we see the 19 total lube yield increased by 2%. Perhaps more importantly, the 100N 20 yield increased by 4% while the 100N pour point dropped slightly. 21 22 The above comparative examples show the unexpected improved 23 performance when recycling a portion of the fractionator bottoms. Because 24 increasing the amount of bottoms recycle will eventually limit the amount of 25 fresh feed that can be processed, economic limits will usually dictate the 26 maximum amount of recycle. 27 WO 99/29810 PCT/US98/26112 -27 1 Table 6 FEEDSTOCKS FOR PILOT TESTING Feed A Feed B WAXY PROPERTIES API gravity 35.9 33.7 Nitrogen ppm 1.6 1.3 Sulfur, ppm 7.3 6.3 Aromatics 6.04 7.7 Viscosity, cSt @ 65C 9.110 11.766 100C 4.24 5.137 Waxy VI 121 118 Pour Point, *C 39 39 Wax Content, wt% 22.96 18.09 Distillation, OF 10% 640 678 50% 787 819 90% 960 970 SOLVENT DEWAXED OIL Viscosity, cSt @ 40C 21.418 30.327 100C 4.306 5.309 VI 107 108 Pour pt, *C -18 -21 WO 99/29810 PCTIUS98/261 12 -28 C) C 0 co 0 - cn 0O co - r- r- co co co cz 04(* 04 0 Q) 0) U)O 0) 0 NJ o C o co I- co C) 0 00 E CL E z L0 0 oC/ C 0 0 00 Ci C O a.0 0 C? CN C? CN C(N C CL 0 o. 3-. 0.0) 0) 0 0) 0) 00 0_ CD Nl D I- co CD CD 0~ 000) ce Co 0 0 V- .E rlLL > 0) Co 00 r- 0 Co U) C) * ' ~ 0 ( 0 0 4) X co. c0 co 0 z 0- -Y (t Co OU CD N,

I-

Claims (42)

VIII. CLAIMSWHAT IS CLAIMED IS:

1. A process for converting a hydrocarbon oil comprising:

(a) contacting a hydrocarbon oil feedstock in the presence of added hydrogen gas with a catalyst system comprising an intermediate pore size silicoaluminophosphate molecular sieve and a hydrogenation component, wherein at least a portion of said feedstock is converted;

(b) passing at least a portion of said converted feedstock to a fractionator, wherein at least a portion of said converted feedstock is fractionated, thereby producing at least one overhead fraction and one bottoms fraction; and

(c) mixing at least a portion of said bottoms fraction with said hydrocarbon oil feedstock in step (a).

2. The process of claim 1 , wherein said catalyst is selected from the group consisting of SAPO-11 , SAPO-31 or SAPO-41.

3. The process of claim 1 , wherein said catalyst further comprises a catalyst selected from the group consisting of an intermediate pore size aluminosilicate zeolite catalyst, an amorphous catalyst, and mixtures thereof.

4. The process of claim 2 wherein said silicoaluminophosphate sieve comprises SAPO-11 and said hydrogenation component comprises platinum.

5. The process of claim 4 wherein said catalyst system consists essentially of a SAPO-11.

6. The process of claim 1 wherein said hydrogenation component is present in an amount of from about 0.01 % to about 10% based on the weight of said molecular sieve.

7. The process of claim 2 wherein the catalyst system further comprises an intermediate pore size aluminosilicate zeolite catalyst and is predominantly in the hydrogen form.

8. The process of claim 7 wherein said catalyst further comprises a hydrogenation component.

9. The process of claim 8 wherein said hydrogenation component comprises a Group VIII metal.

10. The process of claim 9 wherein said hydrogenation component is selected from platinum, palladium, and mixtures thereof.

11. The process of claim 7 wherein said intermediate pore size aluminosilicate zeolite has a Constraint Index measured at from about 400┬░C to about 454┬░C of from about 4 to about 12.

12. The process of claim 7 wherein said intermediate pore size aluminosilicate zeolite is selected from the group consisting of ZSM-5, ZSM-11 , ZSM-12, ZSM-22, ZSM-23, ZSM-35, SSZ-48, and mixtures thereof.

13. The process of claim 7 wherein said intermediate pore size aluminosilicate zeolite catalyst further comprises a metal selected from Group VIII metals consisting of platinum, palladium, and nickel, and mixtures thereof, or Group VIB metals consisting of molybdenum, chromium, tungston, and mixtures thereof.

14. The process of claim 7 wherein the weight ratio of said intermediate pore size silicoaluminophosphate molecular sieve to said intermediate pore size silicoaluminophosphate zeolite molecular sieve is from about 1 :5 to about 20:1.

15. The process of claim 1 wherein said process is a dewaxing process and wherein said contacting is under dewaxing conditions.

16. The process of claim 15 wherein said contacting is carried out at a temperature of from about 200┬░C to 475┬░C, a pressure of from about 15 psig to about 3000 psig, a liquid hourly space velocity of from about 0.1 hr^~1 to about 20 hr^'\ and a hydrogen circulation rate of from 500 to about 30,000 SCF/bbl.

17. The process of claim 15 wherein the amount of said fractionator bottoms mixed with said hydrocarbon oil feedstock is an effective amount to increase yield of said converted feedstock or reduce the pour point of said converted feedstock.

18. The process of claim 17 wherein from about 1 weight percent to about 80 weight percent of said fractionator bottoms is mixed with said hydrocarbon oil feedstock.

19. The process of claim 15 wherein the weight ratio of said fractionator bottoms mixed with said hydrocarbon oil feedstock to said hydrocarbon oil feedstock is an effective ratio to increase yield of said converted feedstock or reduce the pour point of said converted feedstock.

20. The process of claim 19 wherein the weight ratio of said fractionator bottoms mixed with said hydrocarbon oil feedstock to said hydrocarbon oil feedstock is from about 1 :100 to about 60:100.

21. The process of claim 1 wherein said hydrocarbon oil feedstock is a middle distillate oil.

22. The process of claim 21 wherein said feedstock is a lube oil feedstock.

23. The process of claim 22 wherein said hydrocarbon oil feedstock contains less than 50 ppmw organic nitrogen.

24. The process of claim 23 wherein said hydrocarbon oil feedstock contains less than 10 ppmw organic nitrogen.

25. The process of claim 1 wherein said hydrocarbon oil feedstock is waxy bright stock.

26. The process of claim 1 wherein said hydrocarbon oil feedstock comprises a lube oil range raffinate and wherein the process is a process for hydrodewaxing said raffinate comprising contacting said raffinate in the presence of added hydrogen under hydrodewaxing conditions with the catalyst system.

27. The process of claim 1 wherein said hydrocarbon oil feedstock comprises a waxy hydrocarbon feed and wherein the process is a process for improving the viscosity index, relative to conventional solvent dewaxing, of a dewaxed product of said waxy hydrocarbon feed comprising contacting the catalyst with said waxy hydrocarbon feed under isomerization dewaxing conditions.

28. The process of claim 1 wherein at least a major portion of said hydrocarbon oil feedstock boils above about 350┬░F and contains straight chain and slightly branched chain hydrocarbon and wherein the process is a process for catalytically dewaxing said hydrocarbon oil feedstock boiling above about 350┬░F and containing straight chain and slightly branched chain hydrocarbons comprising contacting said hydrocarbon oil feedstock in the presence of added hydrogen gas at a hydrogen pressure of about 15-3000 psi under dewaxing conditions with the catalyst system.

29. The process of claim 1 wherein the process is a process for preparing a lubricating oil:

(a) wherein said hydrocarbon oil feedstock is the effluent of hydrocracking in a hydrocracking zone a hydrocarbonaceous feedstock to obtain an effluent comprising a hydrocracked oil; and

(b) wherein said contacting step comprises catalytically dewaxing said effluent at a temperature of at least about 200┬░C and at a pressure of from about 15 psig to about 3000 psig in the presence of added hydrogen gas with the catalyst.

30. A process for dewaxing a hydrocarbon oil comprising:

(a) contacting, under dewaxing conditions, a lube oil feedstock in the presence of added hydrogen gas with a catalyst system comprising an intermediate pore size silicoaluminophosphate molecular sieve and a hydrogenation component, wherein said hydrogenation component is present in an amount of from about 0.01 % to about 10% based on the weight of said silicoaluminophosphate molecular sieve, and comprising a catalyst selected from the group consisting of a zeolite, an amorphous catalyst, and mixtures thereof, wherein at least a portion of said feedstock is dewaxed;

(b) passing at least a portion of said dewaxed feedstock to a fractionator, wherein at least a portion of said dewaxed feedstock is fractionated, thereby producing at least one overhead fraction and one bottoms fraction; and (c) mixing an effective amount to increase yield or reduce the pour point of said dewaxed feedstock of said bottoms fraction with said hydrocarbon oil feedstock in step (a).

31. The process of claim 30 wherein said silicoaluminophosphate molecular sieve comprises SAPO-11 and said hydrogenation component comprises platinum.

32. The process of claim 31 wherein said silicoaluminophosphate molecular sieve consists essentially of a SAPO-11.

33. The process of claim 30 wherein said aluminosilicate zeolite catalyst further comprises a Group VIII metal hydrogenation component.

34. The process of claim 33 wherein said intermediate pore size aluminosilicate zeolite is selected from the group consisting of of ZSM-5, ZSM-11 , ZSM-12, ZSM-22, ZSM-23, ZSM-35, SSZ-48, and mixtures thereof.

35. The process of claim 30 wherein the weight ratio of said intermediate pore size silicoaluminophosphate molecular sieve to said intermediate pore size silicoaluminophosphate zeolite molecular sieve is from about 1 :5 to about 20:1.

36. The process of claim 30 wherein said process is a dewaxing process and wherein said contacting is under dewaxing conditions.

37. The process of claim 36 wherein said contacting is carried out at a temperature of from about 200┬░C to 475┬░C, a pressure of from about 15 psig to about 3000 psig, a liquid hourly space velocity of from about 0.1 hr¹ to about 20 hr^"\ and a hydrogen circulation rate of from 500 to about 30,000 SCF/bbl.

38. The process of claim 30 wherein from about 1 weight percent to about 80 weight percent of said fractionator bottoms is mixed with said hydrocarbon oil feedstock.

39. The process of claim 38 wherein the weight ratio of said fractionator bottoms mixed with said hydrocarbon oil feedstock to said hydrocarbon oil feedstock is from about 1 :100 to about 60:100.

40. The process of claim 30 wherein said hydrocarbon oil feedstock is a middle distillate oil.

41. The process of claim 30 wherein said hydrocarbon oil feedstock contains less than 50 ppmw organic nitrogen.

42. A process for dewaxing a hydrocarbon oil comprising:

(a) contacting, at a temperature of from about 200┬░C to 475┬░C, a pressure of from about 15 psig to about 3000 psig, a liquid hourly space velocity of from about 0.1 hr¹ to about 20 hr¹, and a hydrogen circulation rate of from 500 to about 30,000 SCF/bbl., a lube oil feedstock containing less than 50 ppmw organic nitrogen, in the presence of added hydrogen gas, with catalysts consisting essentially of a SAPO-11 intermediate pore size silicoaluminophosphate molecular sieve and a hydrogenation component, wherein said hydrogenation component is present in an amount of from about 0.01 % to about 10% based on the weight of said silicoaluminophosphate molecular sieve, and a SSZ-32 zeolitic catalyst containing a Group VIII metal hydrogenation component, wherein the weight ratio of said SAPO-11 to said SSZ- 32 is from about 1 :5 to about 20:1 , wherein at least a portion of said feedstock is dewaxed; (b) passing at least a portion of said dewaxed feedstock to a fractionator, wherein at least a portion of said dewaxed feedstock is fractionated, thereby producing at least one overhead fraction and one bottoms fraction; and

(c) mixing from about 1 weight percent to about 80 weight percent of said dewaxed feedstock of said bottoms fraction with said hydrocarbon oil feedstock in step (a).