US3673078A - Process for producing high ur oil by hydrogenation of dewaxed raffinate - Google Patents

Abstract

Refined mineral oils (useful as textile oils, white oils and agricultural spray oils) which have a viscosity in the lubricating oil range and a volume percent unsulfonated residue (UR) of at least 94.5 are produced from a dewaxed raffinate of a distillate oil obtained from a crude oil classified as paraffinic or mixed-base by ASTM viscosity-gravity constant (VGC), the dewaxed raffinate having a UR less than 93. The preferred process involves contacting the dewaxed raffinate with a hydrogen rich gas and a catalytic amount of sulfur-resistant hydrogenation catalyst at a temperature of about 550* to 750* F., a pressure of at least 1,500 p.s.i.g., and a hydrogen feed rate of about 0 to 10,000 s.c.f./bbl. of feed, at a gas recycle in the range of 020,000 s.c.f./bbl. of feed, said contacting being at a liquid hourly space velocity sufficient to convert said dewaxed raffinate to a hydrogenated oil having a UR of at least 94.5. At 0 or low gas recycle the preferred catalysts comprise sulfided oxides of nickel and molybdenum. When the gas recycle is at least 500 s.c.f. the preferred catalysts also include nickel and the noble metal hydrogenation catalysts (e.g. Pt, Pd, Ru, Rh, Re) and alloys of 2 or more noble metals (e.g. PdRu, PtRe, PtRh, etc.). In one preferred embodiment the contacting is in two or more stages or zones. In the first stage or zone the catalyst is substantially sulfur resistant (e.g. sulfided CoMo, NiMo, NiCoMo, PtS) under the reaction conditions and the product has less than 10 p.p.m. sulfur. In the second stage or zone, the low sulfur product of the first stage or zone is contacted with a more active catalyst for saturation of aromatic rings (e.g. Pt, Pd, Ni, Rh, Re, Rh).

Description

United States Patent Kirk, Jr.

[ 1 June 27, 1972 [54] PROCESS FOR PRODUCING HIGH UR OIL BY HYDROGENATION OF DEWAXED RAFFINATE Primary ExaminerDelbert E. Gantz Assistant Examiner-G. J. Crasanakis Attorney-George L. Church, Donald R. Johnson, Wilmer E, McCorquodale, Jr. and Barry A. Bisson [57] ABSTRACT Refined mineral oils (useful as textile oils, white oils and agricultural spray oils) which have a viscosity in the lubricating oil range and a volume percent unsulfonated residue (UR) of at least 94.5 are produced from a dewaxed raffinate of a distillate oil obtained from a crude oil classified as paraffinic or mixed-base by ASTM viscosity-gravity constant (VGC), the dewaxed raffinate having a UR less than 93. The preferred process involves contacting the dewaxed raffinate with a hydrogen rich gas and a catalytic amount of sulfur-resistant hydrogenation catalyst at a temperature of about 550 to 750 F., a pressure of at least 1,500 p.s.i.g., and a hydrogen feed rate of about 0 to 10,000 s.c,f./bbl. of feed, at a gas recycle in the range of 020,000 s.c.f./bbl. of feed, said contacting being at a liquid hourly space velocity sufficient to convert said dewaxed raffinate to a hydrogenated oil having a UR of at least 94.5. At 0 or low gas recycle the preferred catalysts comprise sulfided oxides of nickel and molybdenum. When the gas recycle is at least 500 s.c.f. the preferred catalysts also include nickel and the noble metal hydrogenation catalysts (eg. Pt, Pd, Ru, Rh, Re) and alloys of 2 or more noble metals {c.g. PdRu, PtRe, PtRh, etc.). in one preferred embodiment the contacting is in two or more stages or aones. In the first stage or zone the catalyst is substantially sulfur resistant (e.g. sulfided CoMo, NiMo, NiCoMo, PtS) under the reaction conditions and the product has less than 10 ppm. sulfur. in the second stage or zone, the low sulfur product of the first stage or zone is contacted with a more active catalyst for saturation ofaromatic rings (e.g. Pt, Pd, Ni, Rh, Re, Rh).

7 Claims, 3 Drawing Figures SINGLE STAGE SPRAY OIL-WHlTE OIL HYDROGENATION PROCESS 2 E FEED Had-H25 HEATER t HYDROGEN JEl RECYCLE it LHSV COMPRESSOR DESULFURIZATION 2 1,000 PSIG I PACKED H23 STRIPPING SEC'HQN I on 0.75 LHSV HYDROGENATION M2 03 GSO'F 1.000 SI 2,o0o-5,ooo SCF/B DESULFURIZED HYDROGENATED o|| LUBE W H25 OIL H m s ABSO a DISTILLATE R ER FEED O|L+ H25 TO PRODUCT DISTILLATION PATENTEUJHNZ? :272 3,673,078

sum 1 or 3 FIGURE l TRICKLE PHASE 96 UR SPRAY OIL HYDROGENATION COMPRESSOR REFORMER 2 I550 PSIG HEATER REACTOR q l l I i CHARGE -J TANK TO FUEL PARAFFINIC LUBE LOW PRESSURE DISTILLATE SEPARATOR 0R 0,,- RAFFINATE 9% ACID GAS TO VACUUM CONDENSERS 5 PSIG 00F H28 STRIPPER I50 PSIG STEAM 5 E 2 PRODUCT T0 STORAGE ATTORNEY P'A'TENTEnJunzv m2 3.673.078

saw a or 3 FIGURE 3 SINGLE STAGE SPRAY OIL-WHITE OIL HYDROGENATION PROCESS FEED H +H S HEATER HYDROGEN RECYCLE I LHSV COMPRESSOR DESULFURIZATION 1,000 PSIG PACKED H23 STRIPPING SEC'HON on 0.15 LHSV HYDROGE NATION M2 03 50's L PSIV 2,ooo-5,ooo SCF/B 4 DESULFURIZED b HYDROGENATED on.

1 b LUBE g H28 4. ABSORBER H25 DISTILLATE FEED 1- ou. H28

TO PRODUCT DISTILLATION INVENTOR.

PROCESS FOR PRODUCING HIGH UR OIL BY HYDROGENATION OF DEWAXED RAFFINA'IE CROSS REFERENCES TO RELATED APPLICATIONS The disclosure of all of the following copending applications is hereby incorporated herein by reference, all of these being assigned to the Sun Oil Company, as is the present application:

Filing Serial No. Date Title/Inventor 636,493 -5-67 Process for Preparing an Aromatic Oil and Non-Discoloring Rubber Composition Containing Said Oil Mills-Dimeler-Kirk Production of High Quality 799,499 now 2-14-69 patent no. 3,594,307

Mills-Dimeler Of particular import is the disclosure in these applications of sulfur-resistant hydrogenation catalysts (particularly those containing sulfuded oxides of Ni, Mo, Co, etc.), since such catalysts can be useful in practicing the present invention. The application of Mills and Dimeler (Ser. No. 850,717) claims a process for producing a technical white oil having an ultraviolet absorptivity in the 280-289 millimicron region less than 2.0 and having a viscosity in the range of 300-600 SUS at 100 F., said process comprising hydrogenating a parafl'inic distillate having a viscosity in the range of 300-600 SUS at a temperature in the range of 550600 F., at a hydrogen partial pressure in the range of BOO-3,000 p.s.i. and a total pressure in the range of 800-6,000 p.s.i.g., in the presence of a hydrogenation catalyst comprising sulfides of nickel and molybdenum, and at a liquid hourly space velocity in the range of 0.1-1.0. The application also claims a process for producing a technical white oil having an ultraviolet absorptivity in the 280-289 millimicron region less than 1.5 and having a viscosity in the range of 50-300 SUS at 100 F., said process comprising hydrogenating a paraffinic distillate having a viscosity in the range of 50-300 SUS at a temperature in the range of 565640 F., at a hydrogen partial pressure in the range of 800-3 ,000 psi. and a total pressure in the range of BOO-6,000 p.s.i.g., in the presence of a hydrogenation catalyst comprising sulfides of nickel and molybdenum, and at a liquid hourly space velocity in the range of0. 1-1 .0.

SUMMARY OF THE INVENTION Lubricating oils with low unsaturated residue (UR) and/or improved color and oxidation stability can be made by hydrotreating with conventional CoMo or NiMo desulfurization catalysts at 500-700' F., 0.2 3 LHSV, ZOO-3,000 psig, with or without recycle hydrogen. Although significant color improvement and reduction of unsaturates is obtained in such processes with sulfided CoMo and NiMo catalysts, their moderate activity limits the extent of improvement at conventional operating conditions. Higher operating temperatures compensate to some degree for activity, but above about 650-700 F the products became unstable. in other words, the selectivity for color removal and stability decreases. Pt, Ni, Pd or similar metal catalysts are several orders of magnitude more active for hydrogenation, but are rapidly poisoned by sulfur in the feed (which can be as high as 0.2 wt. percent for lube boiling range distillates).

In one embodiment of the present invention lubes can be hydrotreated in a two-stage process where the feed (typically containing l00-2,000 p.p.m.s) is desulfurized to less than 50 p.p.m. (preferably less than 10 p.p.m.) of sulfur in first reactor stage, H S is stripped from the product and hydrogenation occurs in a separate second reactor stage. Another embodiment relates to the accomplishment of both reaction stages in a single vessel in which a center zone of packing (which is preferably substantially inert as a hydrogenation catalyst) serves to strip H,S from the product of the first stage. The net result is a simplified process employing a 3 zone reactor with common countercurrent gas flow, to yield a highly refined lube oil product of very light color (and which can have a high UR).

The volume unsulfonated residue (or UR) is an important test measurement in determining the suitability of a given refined mineral oil for use as an agricultural spray oil or as a technical white oil. In the range of 93.5 to 99 UR, the UR is approximately directly proportional to the total wt. percent of aromatics plus olefins in the oil. For example, a 93.5 UR oil has about 13.5 percent aromatics plus olefins, a 96 UR oil has 6.0 percent and a 99 UR oil has about 0.8 percent aromatics plus olefins.

Refined mineral oils (useful as textile oils, white oils and agicultural spray oils) which have a viscosity in the lubricating oil range and a volume percent unsulfonated residue (UR) of at least 94.5 are produced from a dewaxed raffinate of a distillate oil obtained from a crude oil classified as paraffinic or mixed-base by ASTM viscosity-gravity constant (VGC the dewaxed rafi'mate having a UR less than 93. The preferred process involves contacting the dewaxed raffinate with a hydrogen rich gas and a catalytic amount of a sulfur-resistant hydrogenation catalyst at a temperature of about 550-750 F. (preferably 650-700 F. a pressure (in the range of 500-6000 p.s.i.g., preferably at least 1,500 p.s.i.g.), and a hydrogen feed rate of about 0 to 10,000 s.c.f./bbl. of feed, at a gas recycle in the range of 0-20,000 s.c.f./bbl. of feed, said contacting being at a liquid hourly space velocity (typically 0.1-1.0, more preferably 0.2-0.6) sufficient to convert said dewaxed raffinate to a hydrogenated oil having a UR of at least 94.5. Preferably the feed hydrogen is in the range of 50-100 percent pure, and the partial pressure of hydrogen at the reactor inlet is at least 800 p.s.i.a. (more preferred at least 1,200 p.s.i.a.).

At 0 or low gas recycle the preferred catalysts comprise sulfided oxides of nickel and molybdenum. When the gas recycle is at least 500 s.c.f. the preferred catalysts also include nickel and the noble metal hydrogenation catalysts (e.g. Pt, Pd, Ru, Rh, Re) and alloys of 2 or more noble metals (e.g. PdRu, PtRe, PtRh, etc.). In one preferred embodiment the contacting is in two or more stages or zones. In the first stage or zone the catalyst is substantially sulfur resistant (e.g., sulfided CoMo, NiMo, NiCoMo, PtS) under the reaction conditions and the product has less than 10 p.p.m. sulfur. In the second state or zone, the low sulfur product of the first stage or zone is contacted with a more active catalyst for saturation of aromatic rings (e.g., Pt, Pd, Ni, Rh, Re, Rh).

In conducting such a lube oil hydrogenation process in a single reactor vessel having three zones, the same catalyst can be used in the top and bottom zones (e.g. sulfided NiMo oxides or Pt on A1 0 however, it is preferred that one zone (e.g. the top zone in FIG. 3) contain a sulfur resistant hydrogenation-dehydrogenation catalyst (e.g. sulfided NiCoMo oxides) and the final zone (e.g. the bottom zone in FIG. 3) contain a more active, sulfur sensitive hydrogenation-dehydrogenation catalyst (e.g. Ni on kieselguhr, which for 99 UR product requires that the feed to the final zone contain less than 2 p.p.m. of sulfur). In the embodiment illustrated in FIG. 3, the top and bottom lines of the reactor are each loaded initially with the same catalyst (Pt on A1 0 However, during operation, as illustrated in the Figure, the Pt catalyst in the top zone becomes at least partially converted to sulfided Pt catalyst. This conversion to sulfide is caused by sulfur present in the feed stock to the first zone. In the bottom zone sulfide formation is not favored since H s-free, feed hydrogen first enters the reactor at this zone and also because the lube oil feed to the bottom zone is substantially free from sulfur and H 8 (e.g. typically, containing from lppm. S).

BRIEF DESCRIPTION OF THE DRAWINGS In the attached drawings, FIG. 1 is a schematic illustration of a process for producing hydrorefined lube having a UR of at least 94.5 (typically 96-98 UR) from 85-93 UR paraffmic (or mixed-base) lube distillate or raffinate (which is preferably dewaxed prior to the catalytic contacting). Preferably the feed stocks contain less than 900 p.p.m. sulfur. This process utilizes trickle phase hydrogenation (e.g. substantially all of the feed hydrogen is consumed in the reactor either by chemical reaction or by being contained in dissolved form in the reactor effluent). The preferred catalyst comprises sulfided oxides and metals of Co, Ni and Mo (e.g. NiMo, CoMo, NiCoMo, NiW, etc.) preferably on a non-reactive carrier such as bauxite, alumina, kieselguhr etc.

FIG. 2 of the drawings is a schematic illustration of a two stage process for producing 94.5 UR spray oil and/or 99 UR white oil from 80-93 UR paraffinic, naphthenic or mixed-base distillate or raffinates from extraction of such distillates with aromatic-selective solvents (e.g. phenol, furfural, Duo Sol" etc.). Preferably the feed stocks contain less than 800 ppm. of sulfur and are dewaxed (e.g. by methyl-ethyl ketone solvent) prior to the catalytic contacting. In this two stage process, the preferred first stage catalyst is the same as that preferred in the process of FIG. 1. However, the preferred second stage catalyst is a highly active, sulfur sensitive metal (preferably on an inert carrier) such as Ni, Pt, Pd, Ru, Re, Rh and combinations of one or more such metals.

FIG. 3 is a schematic illustration of a hydrogenation process wherein a single reactor has three separate contacting zones. In the zone wherein fresh feed enters the reactor, the catalyst is preferably sulfur-resistant (e.g. sulfided Pt, sulfided NiCoMo, sulfided NiMo oxides, etc.). In the second, intermediate zone, there is preferably no hydrogenation or desulfurization catalyst but only inert contact material (e.g. ceramic rings, beads, inert pellets of clay, bauxite, glass, pebbles, etc. In this second zone the H s-containing product oil from the first zone is stripped of its H 5 content by the contact with the inert packing and with the H S free hydrogen-containing gas from the third contact zone. In the third contact zone the H,S-free, desulfurized lube product from the second zone is contacted with fresh hydrogen of IO-I00 percent purity at a total pressure of at least 800 p.s.i.g. (preferably, l,2005,000 p.s.i.g.). The product from the third zone can be a 96 UR spray oil or a 99 UR white oil (as from a parafi'lnic or mixed base feed) or if the feed is a naphthenic distillate or aromatic extract the product can be a non-discoloring rubber oil (e.g. see previously referred to copending application Ser. No. 636,493) or a refrigerator or transformer oil (e.g. see previously referred to copending application Ser. No. 812,516). This type of three zone reactor vessel is also useful in preparing high luminometer number jet fuel utilizing the feeds and process conditions described in previously referred to copending application Ser. No. 799,499, now U.S. Pat. No. 3,594,307, issued July 7, I971.

ILLUSTRATIVE EXAMPLES Example I Using the process shown in the attached FIG. I, a 70 SUS (at I00 F.) distillate fraction of a dewaxed rafiinate obtained from a paraffinic lube distillate, the fraction having a UR of 92.5, was hydrogenated to produce a 96 UR product. A distillate fraction of a dewaxed raffinate obtained from a parafi'mic lube distillate was preheated and mixed with reformer hydrogen that had been compressed to I,550 p.s.i.g. and passed over a sulfur resistant catalyst (such as the NiCoMo sulfide catalysts sold commercially as Filtrol 500-8 and Filtrol 500-10) at a liquid hourly space velocity of 0.3 to 0.4 volumes per hour per volume at a temperature of 650 F. The reactor efiluent was degassed and cooled to 300 F. with liquid hydrocarbons being removed in a low pressure separation. Hydrogen sulfide in the low pressure separation was removed by steam in an H,S stripper. Clean product of 96 UR was cooled and pumped to storage. Table l summarizes the reaction conditions and reports the properties of a typical 96* UR oil produced by the process of this example. The feed contained 500 ppm. sulfur and the product contained less than 25 ppm. sulfur.

EXAMPLE I] Both a 94 UR spray oil and a 99 UR white oil can be produced by the process shown schematically in FIG. I]. The first stage involves a spray oil section which is similar to that shown in FIG. I except that there is no low pressure separation. A product similar to the Example I products is obtained from the spray oil section. All or part of this product (which is preferably 96 UR) can be transferred to the second stage of the white oil section and hydrogenated to produce a 99* UR white oil.

In the attached Table II, Runs No. HPP-I-l88 and Hppl-l9l represent, respectively the first and second stages of such a two stage hydrogen process. In Table II a low and high temperature (575 and 600 F. respectively for Hpp-ll9l) are reported. These temperatures represent the lowest and highest temperatures observed by a series of thermocouples in various positions in the catalyst bed. In such a catalyst bed the most important temperature is the highest recorded temperature. Table II also reports a number of other single and double stage pilot plants runs.

In the two stage process of this example, the first stage hydrogenation was a trickle phase hydrogenation or zero hydrogen throughput. Only sufficient hydrogen was added to the trickle phase reactor to supply that consumed in chemical combination and that dissolved in the product (and to maintain the operating pressure). In the second stage, or white oil section, H 5 in the feed 96 UR spray oil from the spray oil section is preheated and mixed with reformer hydrogen which has been compressed to 1,500 p.s.i.g. and passed over a platinum on alumina catalyst at a liquid hourly space velocity of 0.25 and 600 F. (although 650 F. is a more preferred temperature). The reactor effluent was depressured and cooled and passed to a low pressure separation where dissolved hydrogen and light hydrocarbon gases were removed. Liquid from the low pressure separator was a 99* UR white oil (e.g. 99.9 UR with UVA of [.66 at 260 millimicrons). The process ofthis example was effected with pure hydrogen at a rate of l0,000 standard cubic feet per barrel of feed. The preferred embodiment is to operate the white oil section in such a manner that the amount of hydrogen added is just sufficient for reaction plus solution losses. In this preferred operation hydrogen consumption rate, for the feed and conditions of this example, would be approximately 200 standard cubic feet per barrel, of which about ISO is reacted chemically with the feed and the remaining 50 standard cubic feet per barrel is dissolved in the liquid efiluent from the reactor.

EXAMPLE III A single stage spray-oil white oil hydrogenation process, as described schematically in FIG. Ill, can be used to produce a 99 UR white oil from an 89-925 UR dewaxed raffinate lube distillate feed. The advantages of this process over that described in Example II are decreased capital equipment cost, increased thermal efiicuency in operation and more effluent utilization of hydrogen. No intennediate separation is required from the spray oil section and the process requires less heating and cooling of the process stream.

The raffinate is preheated and downflow charged to a desulfurization zone containing a fixed bed of Pt on aluminum catalyst (which is sulfided by the feed during the catalytic contacting). Countercurrent to the feed flow is an upward flowing stream of hydrogen at a pressure of 1,000 p.s.i.g. at a maximum contact temperature of 675 F.

Hot liquid product from the desulfurization zone (and TABLE I which contains dissolved H 8) flows downward to a packed 5 C diti section of inert ceramic rings where the H 5 is stripped from Temperature,F 650 the liquid by up-flowing hydrogen from a lower hydrogenation Total pressure, p- 500 zone. The up-flowing hydrogen rate is in the range of 2,000 to Feed as y i Percent H2 85 ,000 standard cubic feed per barrel. 4

Desulfurized and stripped 94 UR spray oil from the packed 13 2 3 recyc section flows downwardly into the lower hydrogenation zone, Product gf which contains a fixed bed of Pt on alumina cataly Th 11., l, percent 2 96. 1 o erating conditions In the lower hydrogen zone are an LHSV Aromatic, wt. percent 5. 86. 4 of 0.75, a maximum temperature of 650 F. (a minimum of Olefins, wt. percent 0. 1 640 F.) and 1,000 p.s.i.g., with upward flowing hydrogen (as Sulfur, P percent pure at the inlet) at a rate of 2,000 to 5,000 standard Gravltyl API 0 bi f et er barrel. Product liquid from the lower Color Sayboh hydrogenation zone serves to absorb hydrogen sulfide from $0.2 volume percent the hydrogen recycle stream. The H 8 saturated product 01] TABLE II Hydrogenation of dowaxed raifinate lube-Catalyst: Engelhard ltd-150, 0.6 wt. percent Pt on A1101, 200 1242., 176.5 gm.

Run No. HPP-1 Fresh Chg" 187 188 189 190 191 192 193 194 195 190 197 19s 199 200 Operating Conditions:

Terrill) .1

0w 585 650 065 62] 575 550 550 020 665 675 625 560 0 High 075 715 700 050 000 675 575 660 700 700 650 580 $00 7 00 Pressure, p.s.i.g 600 1,0 1,500 15 0 1500 1,500 1,600 1,600 1,500 1500 1600 1500 1500 1 600 g isv, vglhliglv 05 052 0. as .3:; 0.3 0. a; 025 0. 2s 0. 21s 0. a0 0. s0 0. 59 0. so 0.

arge s cc res res l rash resh Fresh Fresh F h F F 100% Halo", s.c.f./B 0 0 10,000 10,000 000 10,000 10,000 10,000 5,000 0 00 5rush ii Recycle, s.c.f./B 0,000 20,000 0 0 0 0 u 0 o o 9 Product qualities:

Aromatics, w percent:

%;mo 1. s 1.4 5. 5 3.4 3.11 5.1 6.1 9.7 11. s 19. 4 m 1::5:13:31:j:Jjjj::55:jj jjjjjjjjjjjjjjj. .111...f; .1 in"? "91.

1.6 1.4 5.5 3.4 3.6 5.2 8.2 0.9 12.9 11.1 Oleiins, wt. percent- 0 0 0.4 0. 0. 6 0 0 0 1.7 10 UR, vol. percent 99. 9 9s. 8 99. 5 9o. 1 97. 3 96.7 96. 0 94.9 03.0 9320 Yield, vol. percent of c 99 102 100 100 101 102 102 102 100 104 l Run 188 product. Observed in pilot plant.

"Fresh charge was obtained by solvent dewaxlng of a iurfurel rafiinate of a vacuum distillate fraction of a araiiini crud 'l. w a viscosity of about 70 SUS at 100 F., a viscosity index 01 about 05 and a specific dispersion of about 100. p c e m The fresh charge hm from the lower zone contains 99* UR and is transferred to product distillation to remove H 8 and for adjustment of flash point and viscosity. Table III reports the properties of a typical product of this example and also reports the usual range of product properties which can be encountered in commercial scale operation.

Where the feed to the process of the present invention has not been dewaxed, it is sometimes advantageous to utilize in at least one contacting stage or zone a combination of a hydrogenation (e.g. Ni, Pt) or hydrodesulfurization catalyst (e.g. NiMoSx, PtS) with a hydroisomerization catalyst (particularly an acidic alumino-silicate catalyst which is at least partially crystalline to X-ray and which can adsorb benzene). Such a dual function, hydrogenation-hydroisomerization catalysts and their uses in converting wax to lubes are disclosed in commonly assigned copending application Ser. No. 828,746 of lb Steinmetz and David S. Barmby, filed May 28, 1969 and titled "lsomerization of Waxy Lube Streams and Waxes," the disclosure thereof being hereby incorporated herein by reference.

1 ABTM D445-61 and D446-63.

lclaim:

1. A process for producing a refined mineral oil having a viscosity in the lubricating oil range and a volume percent unsulfonated residue of at least 96, said process comprising a. introducing a mineral oil distillate of lubricating viscosity into a reaction vessel containing a first reaction zone, a second reaction zone and an intermediate zone between said first and said second reaction zones;

b. contacting said distillate in said first zone with a hydrogen-rich gas and a catalytic amount of a sulfur-resistant hydrogenation catalyst to desulfurize said distillate, said catalyst being sulfurized platinum on an alumina, silica, clay or bauxite support;

c. passing the distillate from said first zone to said intermediate zone containing therein a packing material which is substantially inert to hydrogenation and wherein the flow of hydrogen is countercurrent to the flow of distillate whereby hydrogen sulfide which was formed in said first zone is stripped from said distillate;

d. contacting the desulfurized distillate in said second zone with hydrogen and a catalyst comprising metallic platinum on an alumina, silica, clay or bauxite support;

e. said contacting steps in said first and said second zones being conducted at a temperature of about 550 to 750 F. and a pressure in the range of 500-6,000 p.s.i.g, and

f withdrawing mineral oil product from said second zone having an unsulfonated residue of at least 96.

2. Process for producing refined mineral oils which have a viscosity in the lubricating oil range and a volume percent unsulfonated residue (UR) of at least 96, said process comprising a. contacting a mineral oil distillate of lubricating oil viscosity and a UR less than 93 with a hydrogen-rich gas and a catalytic amount of a sulfur-resistant hydrogenation catalyst to desulfurize said distillate, said catalyst being sulfided platinum on an alumina, silica, clay or bauxite support;

b. separating hydrogen sulfide from the desulfurized distil- 8 late;

c. contacting the desulfurized distillate with hydrogen and a catalyst comprising metallic platinum on an alumina, silica, clay or bauxite support;

d. said contacting steps (a) and (c) being conducted at a temperature of about 550 to 750 F., a pressure in the range of 500-6,000 psig and a liquid hourly space velocity sufficient to convert said distillate to a hydrogenated oil having an unsulfurized residue of at least 96, and

e. withdrawing mineral oil product from step (c) having an unsulfonated residue of at least 96.

3. A process as in claim 1 wherein said mineral oil distillate is derived from a crude oil classified as paraffinic or mixed base by ASTM viscosity-gravity constant.

4. A process as in claim 1 wherein said mineral oil distillate is dewaxed raffinate produced by treating said oil with an aromatic selective solvent.

5. Process according to claim 2 wherein the said distillate to step (a) is a dewaxed raffinate having a viscosity in the lubricating oil viscosity range and wherein in said step (a) the temperature is in the range of 585-7l5 F the pressure is in the range of 500-2000 p.s.i.g., the hydrogen is 50-100 percent pure, the LHSV is 0.1-1.0 and wherein in said step (a) the temperature is in the range of 550-700 F.

6. Process of claim 5 wherein the product of said first contacting step has a UR of at least 94 and the product of said second contacting step has a UR of at least 97.5.

7. Process of claim 6 wherein said raffinate has a viscositygravity constant no greater than 0.82 and said product of said second contacting step has a UR of at least 99.0.

i i l i i

Claims (6)

1. 2. Process for producing refined mineral oils which have a viscosity in the lubricating oil range and a volume percent unsulfonated residue (UR) of at least 96, said process comprisiNg a. contacting a mineral oil distillate of lubricating oil viscosity and a UR less than 93 with a hydrogen-rich gas and a catalytic amount of a sulfur-resistant hydrogenation catalyst to desulfurize said distillate, said catalyst being sulfided platinum on an alumina, silica, clay or bauxite support; b. separating hydrogen sulfide from the desulfurized distillate; c. contacting the desulfurized distillate with hydrogen and a catalyst comprising metallic platinum on an alumina, silica, clay or bauxite support; d. said contacting steps (a) and (c) being conducted at a temperature of about 550* to 750* F., a pressure in the range of 500-6,000 psig and a liquid hourly space velocity sufficient to convert said distillate to a hydrogenated oil having an unsulfurized residue of at least 96, and e. withdrawing mineral oil product from step (c) having an unsulfonated residue of at least 96.
2. 3. A process as in claim 1 wherein said mineral oil distillate is derived from a crude oil classified as paraffinic or mixed base by ASTM viscosity-gravity constant.
3. 4. A process as in claim 1 wherein said mineral oil distillate is dewaxed raffinate produced by treating said oil with an aromatic-selective solvent.
4. 5. Process according to claim 2 wherein the said distillate to step (a) is a dewaxed raffinate having a viscosity in the lubricating oil viscosity range and wherein in said step (a) the temperature is in the range of 585*-715* F., the pressure is in the range of 500-2000 p.s.i.g., the hydrogen is 50-100 percent pure, the LHSV is 0.1-1.0 and wherein in said step (a) the temperature is in the range of 550*-700* F.
5. 6. Process of claim 5 wherein the product of said first contacting step has a UR of at least 94 and the product of said second contacting step has a UR of at least 97.5.
6. 7. Process of claim 6 wherein said raffinate has a viscosity-gravity constant no greater than 0.82 and said product of said second contacting step has a UR of at least 99.0.

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