US3663427A

US3663427A - Preparation of lube hydrocracking stocks

Info

Publication number: US3663427A
Application number: US78629A
Authority: US
Inventors: Jeffrey R Thomas; Ib Steinmetz
Original assignee: Sun Oil Co
Current assignee: Sunoco Inc
Priority date: 1970-10-06
Filing date: 1970-10-06
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16
Also published as: FR2112256A1; BE773160A; FR2112256B1; GB1364630A; CA960596A; DE2149910A1; NL7113611A

Abstract

A PROCESS FOR PREPARING HIGH V.I. LUBE OILS OF HIGH QUALITY IN IMPROVED YIELD COMPRISING FRACTIONATING THE 720-855*F., (B) 855 TO 980*F. AND (C) THE RESIDUUM OR A FRACTION BOILING AT FROM 986-1070*F., SOLVENT EXTRACTING FRACTION (B) WITH A SOLVENT HAVING PREFERENTIAL SOLUBILITY FOR AROMATICS SUCH AS FURFURAL, RECOMBINING THE THREE FRACTIONS, AND HYDROCRACKING THE COMBINED FRACTIONS AT FROM 720 TO 800*F. USING A HYDROGEN PARTIAL PRESSURE OF FROM 2,000 OT 3,000 P.S.I. THE HIGHER BOILING FRACTION IS DEASPHALTED IF REQUIRED.

Description

United States Patent 3,663,427 PREPARATION OF LUBE HYDROCRACKIN STOCKS Jeffrey R. Thomas, Claymont, and lb Steinmetz, 'Wilfiiiiig ABSTRACT on THE DISCLOSURE A process for preparing high V.I. lube oils of high quality in improved yield comprising fractionating the stock material into three fractions, boiling at (a) from 720-855 F., (b) 855 to980; F. and (c) the residuum or a fraction boiling at from 986 -p1070 R, solvent extracting fraction (b) ,with a solvent having preferential solubility for aromaticstsuch as turfural, recombining the-three I fractions, and hydrocracking the'co'mbined fractions at from 720 to 800 F. using'a hydrogen partial pressure of from 2,000 to.3,000 p.s.i.-.The higher boiling fraction is deasphalted if required.

BACKGROUND OF THE INVENTION In the past various processes have been used for up The present invention relates to a hydrocracking process wherein the feed stock is prepared so as to provide an improved yield of a product lube oil having arhigh vis-' cosity index. In general this preparation involves'jvacuum fractionating an atmospheric residuum into three lube...

stock streams-which are: I 5. 3

(a) A distillate boiling in the range of 720 (true boilingpoint hereinafter TBP).

(b) A distillate boiling from 855 JTBP fto' ai point in the range of from 980 F. to 1070'F. TBP depending on the particular crude and product lubes, requirements and.

(c) A fraction boiling'above'fraction (b) which may be a distillate boiling at from 980 1070? F. TBP or'a residuum boilingatabove. 1070* F. (TBP). .The fraction (b) is solvent extracted with a solvent having preferential solubility for aromatics to produce a dewaxed oil-having a viscosity index 10 to 30 viscosity index units above the dewaxed oil viscosity index of the charge. (As used herein viscosity index or V.I. is determined by ASTM D2270).' The depth of this extraction generally is greater for lower V.I. charge stocks such as those having a V.I. of 30 to 60 than for charge higher V.I. charge stocks such as those having a VI. of from 60 to 90. In general suitable solvents for this extraction include furfural, acetophenone, phenol, mixtures of phenol and cumene, acetonitrile, nitrobenzene, aniline, 2,2-dichlorodiethyl ether, dimethyl sulfoxide and mixtures thereof. The particular solvent selected is dependent on several considerations such as economics, the depth of extraction required, and characteristics of the particular crude from which the fraction is derived. Generally furfural and phenol are the preferred solvents. The temperature at which the extraction is performed must be below the temperature of miscibility of the oil and the Fee solvent in order to have any extractive separation, and usually is well below the temperature of miscibility for an efiicient operation with good yields of raffinate. Since the present invention normally does not involve dewaxing the charge stock the lower temperature limit for solvent extraction is that temperature at which solids appear in the stock being solvent extracted. The temperature range encompassing all of the suitable operating temperatures for all ofthe suitable solvents is about 0 to 350 F. In the case of furfural, however, a temperature in the range of about 125 to 3 F. is preferably employed. The ratio of solvent to oil to be used is somewhat interdependent on the particular temperature being used. Generally, solvent to oil ratios in the range of 6:1 to 0.25:1 are suitable withratiosof from 4:1 to 08:1 being the preferred range. The equipment employed in carrying out the solvent extraction is not critical and any conventional solvent extraction equipment can be used such as rotating disc contactors, Podbielniak reactors and countercurrent packed bed extraction columns. Either a batch or continuous operation may be used.

When the third component is a vacuum residuum boiling above 1070 F., it should be deasphalted such as by conventional propane deasphalting to produce a deasphalted oil-witha. Ramsbottom carbon content of no greater than 2.0 wt. percent. In accordance with the present inventionno-aiurther upgrading of this component is required. If thethird component is a distillate, such as that 'boiling'in the range of from 960 to 1070 F. no upgrading is required. These components are blended to form a hydrocracker charge containing from 20 to 70 volume "percent of component (a), from to volume percent of the rafiinate of component (b) and from 10 to 40 vol- 'ume percent of component (c). ,The blend feed stock is hydrocracked at from 2,000 to 3,000 psi. hydrogen partial pressure. The hydrocracker iis generally operated at a LH SV (liquid hourly space ivelocity) of from 05 to 1.5. The hydrocracker is best operatedat aterriperature of from 720 to 800 F. Genboiling abovfe650 P. which is 60 to vol. percent of the hyrocracke'r charge and preferably greater than 70 vol. percent of the hydrocracker charge. This depends on the precise feed blend prepared and the viscosity index level desired.- As the desired viscosity index of the lobes increases less of component (c) above can be tolerated in the feed blend and more of component (a) is required.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the examples, Example I is illustrative of the present invention and Examples 2 to 5 illustrate the results obtained using other refining techniques. In each of Examples l to 5 the crude used in a Lagomedia crude having a gravity, API of 33, a sulfur content of 1.2 wt. percent, a viscosity of 54 Saybold universal seconds at F., a pour point of 0 F. and an O.D color of 21,000. In each of the extractions in the examples is carried out using furfural in a volume solvent to oil ratio of 1.5 to 1.0 at 220 F. The properties of the various components as used in Examples 1, 3, 4, and 5 are reported in Table I.

erany'anysmfaetive hydrogenation catalyst can be used- TABLE I Compo- Component B Component nent A,

unex- Unex- Unextracted tracted Extracted traeted Extracted API gravity at 60 F 25. 7 26. 1 27.6 19. 2 25. 8 Initial boiling point, F 686 815 652 589 624 50% point, F 777 923 923 998 1002 End point/recovery Viscosity at 210 F., Cst 5. 2 15. 5 11. 4 26 18.8

842 F./98%; 9 992 F./98%; a 993 F./98%; 4 1,030 F./78%.

The properties of the components used in Example II are reported in Table II. (Both components are unextracted) TABLE II Compo- Component A nent B API gravity at 60 F. 26. 2 23. 2 Initial boiling point, F. 670 717 50% boiling point, F... 791 908 End point/recovery Viscosity at 210 F., Cst 5. 32 11. 97

of asphatic compounds toform a hydrocracker feedstock and catalytically hydrocracking said hydrocracker feed stock at from about 720 to 800 F., a hydrogen partial pressure of from 2,000 to 3,000 pounds per square inch.

2. The process of claim 1 wherein fraction (0) boils at from about 980 F. to 1070 F.

3. The process of claim 2 wherein the solvent extraction is carried out using a ratio of solvent to oil from 4 to 1 to 0.8 to 1.

4. The process of claim 3 wherein the solvent is furfural.

5. The process of claim 4 wherein the solvent extraction is carried out at from 125 F. to 325 F.

6. The process of claim 5 wherein fraction (a) constitutes from 20 to 70 volume percent of the hydrocracker charge stock, the r'afllnate of fraction (b) constitutes from to 50 volume percent of the hydrocracker feed stock, and fraction (0) constitutes from 10 to volume percent of the hydrocracker feed stock.

TABLE 111 Example 1 2 3 4 5 Example 1 2 3 4 5 Feed preparation:

Unextraeted Component A, volume percent 28. 1 64.0 63. 4 26.5 63.7 Unextraeted Component 13, volume percent- 36.0 37. 4 Extracted Component B, volume percent. 45. 8 36.4 13.4 13.4 Unextracted Component 0, volume percent- 26. 1 Extracted Component 0, volume percent 22.8 22.8 Hydrocracked lube, volume percent charge 62. 0 55. 7 56. 9 53. 1 54. 0 Operating conditions:

Catalyst temperature, F-.. 770 779 760 780 765 LHSV, vol./hr./vol 0. 92 0. 08 0. 88 0. 89 1. 21 Hz partial pressure, p.s.i.g 2, 500 2, 550 2, 500 2, 500 2, 500 Reactor gas rate, s.e.f./bbl 4, 389 4, 609 4, 715 4, 247 Lube grade V.I.s:

70 neutral 83 82 91 91 92 100 neutral- 100 102 100 101 100 107 100 103 95 98 95 As can be seen from Table IH the present invention as illustrated in Example I results in a substantially improved yield while maintaining a high viscosity index in the various lube fractions.

We claim:

1. A process for the preparation of lube oils comprising fractionating a crude into a fraction (a) boiling principally at from about 720 F. to 855 F., a fraction (b) boiling principally at from about 855 F. to from 980 to 1070 F. and a fraction (c) boiling above fraction (b) solvent extracting fraction (b) with a solvent having a preferential solubility for aromatic compounds, combining this rafiinate with the other two fractions which frac- 7. The process of claim 6 wherein the hydrocracking catalyst is sulfided nickel-tungsten.

8. The process of claim 7 wherein the catalyst is supported on silica-alumina.

References Cited UNITED STATES PATENTS tions contain their original aromatic compounds exclusive 20818, 93