US2790754A - Production of lubricating oil - Google Patents

Description

April 30, 1957 R. W. B. JOHNSTON ETAL PRODUCTION OF LUBRICATING OIL Filed NOV. 5, 1954 mman-"Zbl INVENTORS ROBERT W. B. JOHNSTON THOMAS P. WIER, JR.

BY: g 74 @am AGENT United States Patent O PRODUCTION' 0F' LUBRICATING OIL Robert W. B. Johnston andn Thomas P; Wier, Jr., Houston, Tex., assignors to Shell Development Company, New York, N. Y., a corporation of Delaware 'fM1111ication4 November 5.,.19.54 Serial No. 467,209

6 Claims. (Cl. 19611-52) This invention relates to a process for producing 1ubricating oils, and Aparticularly the` production of mineral lubricating oils offhigh quality, including.` high viscosity index.

Heretofore, it has been the generalv practice to recover quality lubricating oil components from those crude oils and distillate fractions thereof in which they occur in economically recoverable proportions. It is generally recognized that considerable selection is required in order toy secure proper crudev stocks in adequate supply for the ever increasing demands for high quality lubricating oils. As the proportion of paraflinic crude oil available for processing decreases and the proportion of naphthenie, and particularly of mixednaphthenic and asphaltic base crudes. increases,` the, demands on processing techniques increase in order to,I recover the smaller proportion of componentsof lubricating characteristics.

It is now common practice tov recover the desirable lubricating componentsfrom various straight-run distillate oil fractions by the use of selective solvents to extract out and thereby remove the low quality compo nents such` as; sulfur compounds, oxygenated compounds and aromatics, from the higher quality parainic hydrocarbons. However, such an attempt to separate all of the desirable components fromL thev undesirable ones is not practical by solvent extraction because of the wide v-ariety oftypes of4 compounds present. Furthermore, the relative solubilities of the various types present do not bear any` exact correspondencek to the qualities which are desired in them as lubricants.

As a consequence, oils which contain a marginal proportion of desired components of different types and which contain undesirable components of an intermediate solubility characteristic, cannot be processed economically to obtain a satisfactory yield of an oil of suitable quality. This. isparticularly true of certain, oils of a more naphthenic and aromatic character.

It is, therefore, a p rincipal object of the present invention to provide an improved process for the production of mineral lubricating oils. A more specific object is to provide a process whereby oils `and oil fractions, which contain a relatively minor proportion of components of desirable lubricating oil characteristics admixed with other components of undesirable characteristics for a lubricating oil, of which a substantial proportion has solubility characteristics in selective solventsclosely similar toA those of the desirable components, are effectively processed by a combination of operations to recover the desirable components as a high quality lubricating oil composition. Still another object is to provide a process in which the difcultly separable undesirable components are modified so that an improved selective solvent separation can be effected; The foregoing` objects will be better understood. and others will bev apparentl from the detailed description ofthe invention, which will be, madewith reference to the accompanying drawing in which the. sole 2,790,754 Patented Apr.V 30, 1957 gure is a diagrammatic process ilow sheet for the practice of the invention.

It has now been found that lubricating oils of high quality can be obtained from what are normally considered to be non-lube stocks of high molecular weight petroleum fractions by aprocess comprising; l). achemical conversion at an elevated temperature; (2). adeasphalting as by the use of an anti-solvent therefor, such as a4 light hydrocarbom e. g. propane, and (3) a selective physical extraction of the non-lube from the lube components as by means of a selective solvent or adsorbent. The deasphaltized oil is suitably and preferably dewaxed to reduce the pour point of the oil,veither` before or after the dearomatization step.

Described in somewhat greater detail, lubricating oils of. high quality. can be obtained' from higher boiling petroleum fractions which contain paratinic, naphthenic, and both simple and` condensed ring :aromatic components.4 by a, combination process wherein the oil is first modified by a treating process, which effects chemical changes including one or more of dehydrogenation, cracking, isomerization and condensationwith a splitting of aliphatic radicals from aromaticradicals and a conice .dens-ation of aromatic radicals to form condensed aromatics and asphaltenes, as by: catalytic or thermal cracking, or both, then treated with: a deasphalti'ng agent, such as a light hydrocarbon, to separate the original and the resulting asphaltic` material as by precipitation*r therefrom, and subsequently recovering the desirable components from the deasphalted oil by extraction of the undesirable components in a selective solvent, such as phenol, furfural, nitrobenzene, sulfur dioxide, and theV like. The thus deasphalted andN extracted oilis. then preferably dewaxed, preferably by al solvent dewaxingprocess, in order to recover the. waxes and, tov lower thepour point of the oil. The dewaxedV oilV can be suitably clay treated, or otherwise treated; chemically,A as desired.

The invention is particularly applicable tothe production of lubricating oils fromv the higher-boiling petroleum distillate fractions which are utilized as feedstock to catalytic cracking operations for the production of motor fuels, such as gasoline. By means of the catalytic conversion conditions to which the oil is subjected, there is recoverable, as by distillation from the mixture of cracked products,V a higher-boiling oil fraction,` representingr only a small proportion of thel usual cracking feed stock, which not only is deleterious in, recycle, cracking because, of its inordinate propensity to produce coke on the. catalyst, but itfis, suitable for the recovery of the lube, oil,r components therefrom by. deasphalting and selective extrae.- tion of the aromatic components.

The foregoing will be. made clear by an examination of significant, data; obtained in connection with a catalytically cracked slurry oil from a commercial reiinery operation, as set; forth in Table lg. The slurry oil was sampled under normal operating conditions of approximately 31,000A barrels per dayvfeed to the catalytic cracking unit, and with aproduction of about 700 barrels per day of the slurry oil. The feed charge was a mixture of various distillate fractions and products produced in other operations of theY renery, some fractions ofcourse being too low boiling to contain any components within the lubricating oil:k range. The composite feed had an API gravity of 28.2 at 60 F. andy the Yfollowing distillationcharacteristics: initial boiling point (IBR), 385 "Y F.; 10% over at 556 F.; 50% over at 710 F.; 9.0%, over at` 883 F. and end boilingr point of 10.00 Fp.; the pour point was 80 F.Y n Y (1) API gravity 7.2 (2) Pour point, F +90 (b) Hydrocarbon type analysis (by isopentane deasphalting and alumina and silica gel Chromatography):

Percent Appearance 41) Isopentane asphalt 20. 9 black solid. 22) Catalystnes 0.64

3) Resins 7.8 redsolid. 34) Saturates 38.1 white solid. 5) Monocyclic aromatics 0. 4 A (6) Polyeyclic aromatics 32.2 green liquid.

` c Properties of asphalt of b(1) (1) Softening point, F 121.8 (2) Penetration value 34.0 (d) Properties of saturates of b(4) 2 d 0.797 (API 43.4 at 60 R). i3 Specific dispersion at 90 100.

i. (4) Pour point, F 120.

(5) Yield of 0 F. pour point 65 (2.5% w. on slurry oil oil, W. basi (6) Viscosity data on 12 F. pour point oil Visc. at 100 F., es---" 22.66 (109 Saybolt). Visc. at 210 F., cs 4.540111 Sayholt). Viscosity index 131. (7) Viscosity index of 0 F. 125.

our po 21 1nt oil.

(8 Yield of Deoiled Wax at |25 F., and oil/solvent ratio of 1 :3 (MEK, toluene, benzene commercial dewaxt in solvent), percent W.

(92 Felting point of wax,

(10) Penetration of wax..-"

(,11) Normal paralns by urea extraction, percent w. of saturates.

(c) Properties of PolycByclics from b(6) 1-12 (1nol.wt.:460i46).

1.9 nm. (100 g., 5 sec. at

27.0 (16.2% w. of slurry oil).

(1; Pour point, 30

(g giensity (90/4) 1.028

sc s

( At 2110911, cs 6.85

At 240 F., es 4.09

Analysis of another catalytically cracked slurry oil, obtained from a diierent operating refinery catalytic cracking unit, by conventional silica gel adsorption techniques with 5% 4benzene in petroleum ether and acetone as eluting agent for the adsorbed hydrocarbons, gave, on a deasphalted and deresined basis, 41% paraliins and napthenes (saturates) and 59% aromatics. Dispersion data indicated the aromaticsto be composed of about 5% monocyclics, 2% dicyclics, 70% tricyclics and 23% tetracyclics. Solvent extraction and distillation fractionations indicated C21 to Cna normal parains to be present as major components of the 41% saturates portion of this slurry oil.

Based upon the foregoing results, another portion of slurry oil, taken from the same catalytic cracking unit for which the data are given in Table I was processed by subjecting it to the combination of a propane deasphalting, phenol extraction, solvent dewaxing, and clay contacting. Based on the slurry oil charge, yields in the diierent steps were approximately as follows: asphalt 36 percent w., extract 32 percent w., slack wax 20 percent w. and finished lubricating oil l2 percent w. The finished oil had a gravity of 31.9 API, viscosity index of 107, Saybolt Universal viscosity of 132.4 seconds at 100 F., and a pour point of +25 F. Pertinent data, including processing conditions and properties of the various products, are given in Tables II-V.

Average molecular weight 28829 Hempel vac. distillation:

Percent w. Overhead, Cumulative Temp., FJ

e Converted to 760 mm. Hg pressure by U. O. P; Method E-7G.

Table IIL-Deasphaltng slurry oil (lower process) Propane-to-oil ratio 6.4 Temperature gradient, F 122-137 Recovery, slurry 011 basis, percent w.

Deasphalted oil 61.2 Asphalt 35.1 Unaccounted for 3.7 Properties Deus halted oil ravity, API at 60 F 19.4 Viscosity, SU at 170 F., sec 48.9 210 F. 40.9 Refractive Index (mo) 1.5233 Hempel vac. distil ation Percent W. Overhead, Cumulative Temp., l`.e

IBP 45t 50.1 745 90.3 (EP) 885 l Converted to 760 mm. Eg pressure by U. O. P. Method E46.

Asphalt Specific doo 1.1696

Gravity,

Viscosity, SU at 170 F., sec 3564 2 418.2 Flash point, PMCC. F 230 softening point, F 96 Penetration, mun/10 g 103 Penetration index -3 Table [V2-Phenol extraction of deasplmlted slurry oil Run conditions (countercurrent tower extraction) Phenol-to-oil ratio 2 98 Temperature gradient -180 linear gradien Water addition With phenol, percent w 0.647.

At bottom, percent W 10.7. Recoveryaflina 49.5.

Extract 50.5. Properties- Rainate:

Gravity, API at 60 n Viscosity, SU at 17 F., sec

210 Flash point. COC, F Refractive index (nn'm) Extract- Gravity, API at 60 F 6.0. Viscoslty,'SU at F., sec ,79.5. 10 1l' 49.2. Flash point, COC, B 400.

Table V.-Dewaxing raffinate Solvent 100% methyl ethyl ketone. Solventtooil ratio 3.0. Filtration temperature, F +5..

Wash solvent oil ratio ll/z.

Wash solvent temperature, F- +5.

Recovery:

Dewaxed oil, percent-VL- 37. Slack wax (71% soft WaX, 62;

29% deoiledwax).

Table Vlr-Properties of finished oil 'Clay Acid and Treated Clay Oil Treated Oil Gravity, API at 60 F 31.9 31.9 Viscosity, SU at 100 F., sec 132. 4 136. 1 Viscosity Index 107. 3 111 Pour Point, F +25 +40 Fiash Point, PMoo, ir. 29o olor, NPA 5+ 5+ Refractive Index (m70) i. 4604 Specific Dispersion 110. 5

The properties of the deoiled wax of Table V are given in Table VII, including its fractionation by filtration in solvent at progressively lower temperatures. Thus it has a melting point of about l140 F., an index of refraction at 90 F. of about 1.427, and is a mixture of waxes having melting points ranging from about 117 F. to labout 147 F. and most of which throughout the melting point range, by their refractive indices, are normal paraiinic hydrocarbons, with a small proportion of isoparaiiinic waxes throughout the melting point range and essentially free from naphthenic and aromatic hydrocarbons.

Table VIL--Slurry oil deoled wax Melting point, ASTM, F 140.1 Refractive index (nDg) 1.4272 Melting point distribution:

Yield, Anno Filtration Temp., F. Percent w. M. l? (Fraetion+ Cumula- F. n-Paraiin of tive same M. P.)

The acid and clay nished oil, for which specifications are given in Table VI, Was evaluated to determine its suitability for various uses. The London Heat Test and the Continental Oxidation Test indicate good color and oxidation stability for the oil. The susceptibility of the oil for additives is shown by the Dornte Oxidation Test. The response to octyl formol, the calcium Salt of the octylphenol-formaldehyde condensation product containing an average of about 4-5 octylphenol units per molecule, was excellent, particularly for iron catalyst. The finished oil was tested in a hot wire quench test to determine its utility as a metal quenching oil. Performance here was essentially the same as that of a good commercial quench oil. Since the slurry oil has already exhibited high resistance to cracking in the catalytic cracking, it was expected that it would exhibit good thermal stability. A study of its thermal stability under quenching and Martempering conditions demonstrated that it was outstanding `in its resistance to cracking. Oxidation stability of the oil at a high temperature (400 F.), to determine its stability under Martempering conditions,

evaluations are tabulated inTable VIII.

Table VIII.,.-,Evaluatian ,0j finished slurry oil Orig. 3 hr. 18 hr. 30 hr. 48 hr.

London Heat Test (Color)- D5+ DB-l- 135+ D5+ 6+ [Continental Oxidation Time] 10 mg. time 100 mg. time Oxygen uptake 22 hr 72 hr.

24 hr. 48 hr. 72 hi'.

Viscosity Increase 1. 5 1. 9 Sludge 12. 1 41. 7 87. 5

[Dornte oxidation test at 313 F., time in minutes] Cu Fe Catalyst Catalyst Finished Slurry Oil 40 160 Finished Sliirry O' +0.25% W-2, G-ditertiarybntyl- 4methy1phenol 220 150 Finished Slurry Oil +0.5% w-2, G-ditertiarybutyl- 4-methylphenol 390 240 Finished Slurry Oil +0 02% (sulfate ash) of Octyl Formel 830 1, 670

Hot wire quench test: Max. amp.2 Finished slurry oil 500 Rened HV1 lube oil of 100 SUS Visc. at

100 F 470 Refined HVI lube oil of 100 SUS visc. at

` 100 F.+sodium sulfonates 530 [Thermal Stability (Temperature: Boiling Point; minutes).

Percent kDrop in Drop in .1, Gas Col,- SUS Visc. F. lected, cc. at F.

Refined Slurry Oil 7. 6 40 400 Refined HVI lube oil of 100 SUS [Oxidation test (400 F., 72 hr. 1 0111.2 iron Wire/cc. oil-5 liter air/hn).

Orig. Visc. Viso. After Percent SUS at Oxid. SUS Increase 2109 F. at 210 F.

Finished Slnrry Oil 42. 7 74. 95 76 Refined Bright Stock Lube Oil 88.3 154.8 75

(WTE) Refined Bright Stock Lube Oil (East Texas) 8 3. 4 181. 8 P 118 a 76 hour test.

It is to be vseen from the foregoing that the present' hydrocarbons of lubricating viscosity.

7 cracked products are then fractionatedby distillation to separate a higher boiling fraction with a boiling range Acorresponding to that of at least a substantial portion of It may of course contain some of the even lower boiling components, but it is preferred to eliminate bythe distillation the larger proportion of such hydrocarbons which are outside (below) the boiling range of lubricating oil components. Thus, only a minor proportion of the material should boil below about 650 F. and it is preferable that the major .portion boil above about745 F. at 76() mm. Hg. The

heavier oil fraction is then treated to effect a rejection of the asphaltic materials, as by dilution of the oil with an asphalt anti-solvent. For this purpose, the Cz--Cs hy- 'drocarbons are particularly suitable, such as propane,

butane,lisopentane, hexane and mixtures thereof. This prior deasphalting is advantageous in that it minimizes difficulties, such as associated with phase separations, in the subsequent extraction operations and at the same time makes it possible to obtain an eective separation between the lubricating components and the aromatics. The deasphalted oil is separated by selective extraction into a saturate fraction comprising the desirable nouaromatic hydrocarbons, and anV aromatic fractio'mpredominantly polynuclear in character. traction, as already shown, can be carried out readily now by selective solvent extraction, as by use of any of the Well-known selective solvents, such as phenol, furfural, nitrobenzene and liquid sulfur dioxide. On the other hand, a selective adsorbent extraction can be utilized, as already shown, using any of the well-known selective solid adsorbent agents, such as silica gel, alumina, and the like.

The non-aromatic fraction obtained by the selective extraction, called the raiiinate, is suitably dewaxed, preferably by dissolving the raffinate in any of the well-known dewaxing solvents, such as methyl ethyl ketone, methyl isobutyl carbinol, acetone, and the like, and mixtures thereof with aromatic hydrocarbons, such as benzene and toluene. A suitable common commercial dewaxing solvent mixture is composed of methyl ethyl ketone (MBK), toluene and benzene. These solvents can be used together' with a light hydrocarbon, such as propane, a portion of which can be evaporated from the resulting mixture to effect 'the required refrigeration.

thereof made with reference to the accompanying drawing. A high boiling petroleum distillate feed, such as a vacuum flashed distillate as is conventionally used as a catalytically cracking feed stock, is conventionally cracked in the catalytic cracking zone 11. The cracked products are then fractionated by a conventional method such as by fractional distillation in a fractionation zone 12 with the separation of gas, gasoline, naphtha, light gas oil and heavy gas oil distillate fractions and a residual slurry oil comprising essentially a heavy gas oil fraction containing catalyst fines suspended therein. The slurry oil is then suitably deasphalted in a deasphalting zone 13 by the use of a suitable deasphalting agent, such as propane. The separated asphalt phase is transferred to stripper 15 wherein the propane is stripped from the asphalt as by a pressure reduction, steam stripping or the like, and the propane removed overhead is transferred to the deasphalting zone. The deasphalted oil is processed in stripper 14 to remove the propane, which 1s recycled to the deasphalting zone and the stripped `cleasphalted oil is transferred to solvent extraction zone 16 Iwherein it is suitably solvent extracted with a conven- This selective extional selective solvent, such as phenol, furfural and the like. The solvent selectively extracts aromatic components from the oil to produce an extract phase and a waxy ratlinate phase. The extract phase is transferred to a stripper, or solvent recovery zone, 17 wherein the solvent is separated from the extracted aromatic components and the solvent is recycled to the solvent extraction zone. The waxy raffinate from the solvent extraction zone is dewaxed in Vdewaxing zone 18 by suitable conventional dewaxing process such as a solvent dewaxing process utilizing a dewaxing mixture of methyl ethyl ketone, toluene and benzene. The dewaxed oil and the wax are thereby separated and are recovered as separate products for utility as desired.

We claim as our invention:

l. The process of producing a lubricating oil comprising the steps of: crackingqa substantially non-lube oil, gas oil feed stock, boiling in the boiling range 0f hydrocarbon lubricating oil components, at an elevated hydrocarbon-cracking temperature; fractionating a high boiling oil fraction from the cracked products boiling in the range of the boiling range of hydrocarbon lubricating oil components; deasphalting the separated fraction by mixing it with an asphalt anti-solvent to insolubilize the asphalt in the oil; selectively extracting aromatic components from non-aromatic components of the deasphalted oil; and including the step of dewaxing the high boiling oil fraction subsequent to the deasphalting step, whereby a high viscosity index lubricating oil is obtained.

2. VThe process of producing a lubricating oil comprising the steps of: cracking a high boiling petroleum oil stock, containing components having boiling points in the boiling range of hydrocarbon lubricating oil components, at an elevated hydrocarbon-cracking temperature; fractionating a high boiling oil fraction from the cracked products and containing components boiling in the boiling range of hydrocarbon lubricating oil components; deasphalting said oil fraction with a light C2-shydrocarbon; selectively extracting aromatic components from nonaromatics of the resulting deasphalted oil with a selective solvent therefor; and dewaxing the non-aromatics fraction resulting from the solvent extraction, whereby a high viscosity index lubricating oil is obtained.

3. The process of producing a lubricating oil and a distillate hydrocarbon wax comprising the steps of: catalytically cracking a high boiling, substantially non-lube oil, gas oil feed stock; fractionating a high boiling oil fraction including lubricating oil hydrocarbons from the cracked products; deasphalting the lubricating oil-con taining fraction with a light Cz-s-hydrocarbon; solvent extracting the deasphalted oil with a selective solvent to produce a substantially non-aromatic waxy raffinate; dewaxing the raffinate, whereby a high viscosity index lubricating oil is-obtained; and deoiling the oily-wax produced in the dewaxing step, whereby a distillate wax consisting predominantly of n-paraliinic hydrocarbons and a minor amount of isoparaffinic hydrocarbons throughout its melting point range is obtained.

4. The process of producing a lubricating oil comprising the steps of: catalytically cracking a high boiling, substantially non-lube oil, petroleum oil feed stock; fractionating a high boiling oil fraction containing lubricating oil hydrocarbons from the cracked components; deasphalting the oil fraction with a Cms-hydrocarbon; selectively extracting aromatic components from non-aromatic components of the deasphalted oil; and solvent dewaxing the non-aromatic raffinate separated in the preceding selective extraction step, whereby a high viscosity index lubricating oil is obtained.

5. The process in accordance with claim 4, wherein the C24-hydrocarbon is propane and the selective extraction is carried out with a phenol-water selective solvent.

6. The process in accordance with claim 4, wherein the Czshydrocarbon is isopentane and the selective extraction step is carried out with a selective solid adsorbent. 5

References Cited in the le of this patent UNITED STATES PATENTS

Claims (1)

1. THE PROCESS OF PRODUCING A LUBRICATING OIL COMPRISING THE STEPS OF: CRACKING A SUBSTANTIALLY NON-LUBE OIL, GAS OIL FEED STOCK, BOILING IN THE BOILING RANGE OF HYDROCARBON LUBRICATING OIL COMPONENTS, AT AN ELEVATED HYDROCARBON-CARCKING TEMPERTURE; FRACTIONATING A HIGH BOILING OIL FRACTION FROM THE CRACKED PRODUCTS BOILING IN THE RANGE OF THE BOILING RANGE OF HYDROCARBON LUBRICATING OIL COMPONENTS; DEASPHALTING THE SEPARATED FRACTION BY MIXING IT WITH AN ASPHALT ANTI-SOLVENT TO INSOLUBILIZE THE ASPHALT IN THE OIL; SELECTIVELY EXTRACTING AROMATIC COMPONENTS FROM NON-AROMATIC COMPONENTS OF THE DEASPHALTED OIL; AND INCLUDING THE STEP OF DEWAXING THE HIGH BOILING OIL FRACTION SUBSEQUENT TO THE DEASPHALTING STEP, WHEREBY A HIGH VISCOSITY INDEX LUBRICATING OIL IS OBTAINED.

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