US2255283A - Refining of heavy oils - Google Patents

Description

Sept. 9, 1941.

Filed Nov. '21 1958 MIXED BASE C QLIDE RES/DUUM osA-spuALrgp v ASPHALT DEM/A XED WAX

DE R-E SI NE D VISCOUS OIL MILD SOLVENT EXTRACT v 0/? ACID TREAT I RES/NS OR ACID TREAT SEVERE SOLVENT I ll l I EXTRACT i i max/r CLAY TREAT HEAVY CL,4Y TREAT H/GA/ Y/ELD OF H/GZ/ QUAL/TV O/L INVENTOR ATJ'ORNEY Patented Sept. 9, 1941 aarmmc or miavronls Henry 0. Forrest, 'leaneck, N. J., assignor to Standard OilCompany, Chicago, 111., a cor-p ration of Indiana Application November 21, 1938, Serial No. 241,552

I 2 Claims. This invention relates tothe refining of heavy oils, and it pertains more particularly to an improved combination process for obtaining maximum yields of high quality lubricating oils from residual or resin-containing lubricating oil stocks. The object of the invention is to provide a new and improved combination of refining steps for the processing of residual stocks or heavy distillate stocks containing an appreciable quantity of resins, whereby maximum yields of high quality lubricants are obtained, which lubricants are characterized by stability against oxidation, discoloration, sludge formation and carbon depositing tendencies, and which lubricants are further 7 characterized by a high viscosity index (V. I.) and a low viscosity gravity constant (V. G. C.) A further object is to produce maximum yields of a heavy lubricant in which the C'onradsen carbon, or carbon residue is less than 1% of the Saybolt viscosity of the lubricant at 210 F. A further object is to provide a more efficient and efiective refining system than has heretofore been available, and to correlate the steps of the processes and the treating conditions in each respective step, so that at no stage in the process will there be a loss of valuable lubricating oil. A further object is to correlate and integrate a lubricating oil refining process so that each step of the process maybe carried-out at minimum expense and with maximum efiiciency, and so that the combination of steps results in larger yields and higher qualities thancan be obtained by any process or combination of processes heretofore known.

A further object of the invention is to provide a refining process for heavy oils in which the byproducts consist essentially of high melting point asphalts, low gravity extracts or combinations thereof, and wax. The amount and quality of material rejected from the process is one measure of the efliciency of therefining operations and the object of the invention is to obtain maximum noveltyin any of these particular processes per; se."- The present invention correlatesthese the lubricating'oil content of which is normal' processes in a novel manner and interrelates the operating conditions in the several processes and the stocks charged thereto so that; the combination of processes leads to results which could not be accomplished by any combination of the processes heretoforeused. In other words, the operati'ng conditions in each process are dependent upon the operating conditions in other processes and the stocks charged to and produced by said other processes. Overall savings in amounts of treating agents and in treating costs are thereby effected.

It is recognized in the industry that separate treatment of light distillates and residuals is advantageous for obtaining maximum yields and equal product quality from both stocks. It has been generally considered that a residual stock,

bright stock, is one fraction and the lighter distillates are the other fractions. One object of this invention is to adapt the step of propane deresining to separate the residual stock itself into two fractions, one having a viscosity of less than 300 S. S. U. at 210 F. and the other being a heavier fraction. By subsequent severe treatment of the heavier, or resin, fraction a high quality, high viscosity lubricating oil can be obtained. This material, per se, is a new product of high viscosity, but even more important is the fact that it may be blended with the less viscous fraction to give a product in which the fractions of different viscosities have separately controllable quality. It has been the usual procedure to treat the entire cylinder stock as one fraction with inadequate quality improvement on the heavier portion, but the step of propane deresining, followed by severe treatment of the heavier and. more viscous fraction, enables the refiner to obtain any desired quality on both this fraction and the less viscous oils.

Heretofore refiners have endeavored to minimize the amount of resins produced because they were not deemed suitable as components of high quality lubricants. In practicing my invention either a small or a large resin fraction is purposely separated from a heavy lubricating oil stock, either in the presence or absence of asphaltic materials, and this resin fraction is separately refined by acid treating, solvent extraction, clay treating or by a combination of two' or-more of said processes, so that extremely valuable components are separated from these resins for blending with the deresined lubricant. The acid but exceptionally effective. The invention is not limited to the use of phenol, however, since other solvents such as cresylic acid, cresols, chlorphenols, mixtures of such phenolic solvents with small amounts of water, dichlorethyl ether, furfuraLnitrobenzene, etc. may be used either on the resins or on the deresined oil, as will be hereinafter described.

In practicing the invention the heavy residual or resin-containing stock is first fractionated on the basis of molecular weight to give a viscous oil fraction having a viscosity less than 300 seconds Saybolt at 210 F. and a resin fraction having a viscosity of about 300 seconds Saybolt to 1000 seconds Saybolt at 210 F. This initial fractionation is important because it removes from the resin fraction certain viscous oils which, if allowed to remain with the resins, would be severely overtreated with a consequent loss in yield under the conditions required for adequate solvent extraction, acid treating or clay treating of said resin fractions. The resin fraction is then acid-treated, extracted with phenol or clay treated under severe conditions, while the separated viscous oil may require little or no subsequent refining. A mild treatment of the viscous oils, as distinguished from the heavy treatment of the resin fraction, prevents the destruction of large amounts of the viscous oil.

An inherent and important advantage of my process lies in the fact that the blending of the separately clay treated resins with the viscous cylinder stock produces a final product characterized by a highly desirable cast. The general appearance and cast of a bright stock is sometimes impaired during the acid treating or sol vent extraction thereof and the problem of preserving or obtaining the desired cast has bafied oil refiners for years. I have found that by separately clay treating the resins in accordance with my invention and then blending the sepmonly referred to as resins. I have found that when residual oils in the cylinder stock range are fractionated with propane, that fraction having a viscosity below about 290 to 300 seconds Saybolt at 210 F. is substantially free from resins, while the fraction ranging in viscosity from about 300 to 1000 seconds Sayboltat 210 F. contains tures, depending on the particular stock undergoing treatment, the essential feature of this step being the separation of viscous oil from resin fractions, as herein defined. While propane deresining is my preferred method of separating resin fractions from viscous oil, it should be understood that any other fractionating may .be

employed that will produce the desired separation.

The viscous oil fraction in the case of Pennsylvania oils may require no further treatment whatsoever. In the case of mixed base crudes the viscous oil fraction may be given a light acid treatment but it is preferably extracted with a selective solvent such as phenol under mild operating conditions, i. e. at temperatures below 200 F. and at solvent ratios from about 1:1 to 3 21. It is desirable to dewax this deresined oil prior to phenol treating when the dewaxing is effected in the absence of viscous 011 components initially removed therefrom in the origiarately clay treated resins with a bright stock having poor cast characteristics the finished product is characterized by an excellent cast with in connection with residuums from Pennsylvania and mixed base (Mid-Continent) crudes. The invention is only applicable, however, to the relining of heavy oils which contain viscous high molecular weight compounds which are comha] fractionation step.

The resin fraction in the case of Pennsylvania or Pennsylvania type stocks is given a severe acid treatment or solvent refining treatment such as extraction with phenol at temperatures higher than 200 F. and solvent ratios of about 2:1 to l /2:1. With these high solvent ratios and high treating temperatures an extract may be removed having an A. P. I. gravity of about 8 or 9 and a raifinate can be obtained which has an A. P. I. gravity of about 23.5 and a V. G. C. of about .810 to .816.

After the rafllnate is freed from solvent it may be percolated in naphtha solution through Attapulgus clay or other clay equivalent thereto at a temperature of about 180 F. The clay yields may range from about 3 to 5 barrels per ton, but since it is only the resin fraction or resin rafiinate which has to undergo this clay treatment, a considerable savings in clay is effected. The overall clay yield in one example of my process was about 26 barrels of blended oil per ton of clay. If the oil had been percolated through clay before fractionation, in accordance with processes heretofore'used, the clay yield would have been less than 11 barrels per ton. Since clay treating is the most expensive step in the refining of these viscous lubricating oils, the enormous savings effected by the use of this invention will be obvious.

It would be expected that the use of such a small amount of clay would result in a blend of doubtful color stability, oxidation stability and sludge and carbon forming tendencies. The fact is, however, that the finished blend is characterized by excellent color and color stability. The

blend is stable against oxidation and sludgetorming and it has a carbon residue which is less than 1% or the viscosity of the finished blend phenol treating'step, and that after clay percolation of the phenol rafllnate of the resin fraction, the blend with deresined oil gavea. yield ofy92.1% .with an A. P. I. gravity of 26.2, a. viscosity at 210 of 167, a carbon residue of 1.47%

and a V. G. C. of .809. On dewaxing the yield was reduced to 78% with a gravity of 25.3; the

viscosity was increased to 176.7, the carbon residue to 1.63 and the V. G. C. to 1.814.

10 In Fig. 1 the letters "T. R. refer to Tag Robinson color, "C. R." indicates carbon residue and S. P." stands for solid point. The remaining indlcia are believed to be self-explanatory.

TABLE 1 Pnoclssme ALLEGHENY 0mm Sroox API gravity-h BSU Vis. 210

I Demined oil I I Resins -Asphalt Vol. percent Vol. percent"--. 25. 9 Vol. ormant; 6.1 API API- 21.7 AP 14,0 V/2l0.- 521 R 300 O. R get 5. 8 V. G. I .827

0.3., percent 8. 1

Pmmor. Tam-mm 701., percent solvent 345 Vo1.,percentwaterlnjected. 9.4

APL 23.8 V/210---- 569 O.R.. ercent 4.2 V. G. 0

701., percent 75.3 (24.17 based one go) Extract Vol., percent- 24.7 (7.9 basedon char e API 9.1 g)

CLAY Pnncomrrou Wm: Nuns-as AT 180F.

PROPANE DEWAXING S F V. G. C 814 Vol. percent" 15.3(14.l based on cha e M. 1' F 116 rg) 1.0537, a melting point of 147 F. and constituted 28.5% of the stock charged.

The resin fraction which constituted 25.2% of the stock charged was extracted with phenol under severe conditions, i. e. a temperature up to 211 F. and a solvent ratio of about 4:1. This resulted in the elimination of slightly more than half the resiniraction (13.2% o! the stock charged) as an extract whose API gravity was TABLE II Paocrsemc Attzcnnur Crunnra Srocx API gravity 24.4 831') Via, 210F. -L. 201 0101', R- IKDD Car. ma, percent-. 2. 1 G .818

I Paorm DIASPEAL'HNO mp DIBIBININO Vol. percent Cato resin washer.. Temp F. esph. settler Resin Rosin Washer i Damned oil Retina AspLalt v01. rcent 65.6 Vol. reent Vol. rcent 6.0 "APfi 26.6 APE. MFR 14,5 v 21o 113.8 T. R 2% 'I. R C. R., rcent 1.20 C. 12., (percent. V. G. nu... .812 V. G.

Pnniqor. Tnnumo I Rafllnate Edrad Vol. rcent... 88.8 (25.27 based on charge) Vol. rcent..- 11.2 (3.2 based on charge) 1P8.-- 2;.4 AP 8.0

CLAY Pracom'non Wrrn Nam-1m A! 180F.

Paomm: Dswaxma Vol. percent Cl... 300 mu. temp. "F 31 Dcwazcdoll Was V i. went... 85.3 77.47 based on charge) Vol. percent- 14. 703.47 based 011 char e irif 25.1 M. P. 117 a g V1210--- 166.0 T. R 1% (LR. percent. 1.50 SP 1 -2 The application of my process to a mixed base crude is illustrated in Table III which shows the processing of a 7% Burma residuum. In this case the stock was first deasphalted with a 4:1 propane ratio ,at a temperature of F. (washing temperature F.) and the deasphalted oil was then deresined with a 2.1 propane ratio at a temperature of F. (washing temperature 140 F.) with an additional 20% of propane. The separated asphalt had a specific gravity of solvent ratio of 3.23:1).

' 9.1. The vramnate, after removal of solvent, was propane dewaxed for the removal of 61.6% of these removed resins are subjected. If the resin grade residual stock is converted into 28.5% as-- phalt, 31.6% wax, 21.6% or very low gravity extract and 18.3% high quality lubricating oil.

ditions which are required for the viscous oil.

Byfractionating with propane to separate an oil with a viscosity of about to 300 seconds Saybolt at 210 F., and a resin fraction with a viscosity oi." about 300 to 1000 seconds Saybolt at TABLE In Psocassmo humour 7% Rssmuml API gravity 17.3 SSU Via, 210 F 235 V. G. O .374

' PROPANE Dmsrrummo AND Ditaasmmo .Demmedoll Propane dawning Phenol treating Vol. percent...-. 300 Vol. percent solvent--..- 402 Filtr. Temp. F. Ave.. -43 Temp. F. top.-. 211

Btm 169 I v I I Water iniectedlpercent. 10.0

Dewuzed ,oil( 3.1%ojchorqe) or M. P. "F.144 (24.2%oi charge) .Raflimie Eztmd Phmoltrealing 145 Water iniected, pelreentn 9.8

Lopane dawning Volume, percent or..." 300 Filt. temp. F. Ave-.- -42 Dcwured oil fraction is.too large (i. e. if it contains too much of the viscous oil), then the overall yield will be low when sufficiently severe treating conditions are used to properly treat the heavy resins. If

the resin fraction is too small (1. e. if some of the resins are separated with the viscous oil) the heavy fraction is not adequately treated and the color of the treated oil is not satisfactory, clay consumption is too great or the overall yield is impaired because of the more severe treating con- Rafiinaie Extract Wu Vol. percent 62 01%?! 0 Vol. percent-38.0 (8.4%01 charge) Vol. percent.-. 38.4(452, of) V0]. percent... 61. 6 (7.4% of charge) ge 23.6 $6 an 4.9 API---.--..-- 27.9 I M. r., r 159 28. 6 W210 123. 3 00 11.76 V1100. 1710 2% se a .29 o 4 s. 1. 14

545 V; L 20 V. G.

92. 2 1 801 74.0 vol. cent 25.1 vol. percent W Vol. percent... (18. 3% of charge) AP 28.6

210 F., it is possible to obtain maximum yields of high quality oils with minimum treating costs. An outstanding characteristic of the finished oils is their good color and color stability and their low carbon residue which is less than 1% of their viscosity at 210 F.

The specific effect of my method'of processing on the quality of the heavyresin fraction of the cylinder stock is shown by the results in Table IV obtained by processing the Allegheny residuum of Table I. The residuum was treated with 163% of phenol using a tower top temperature of 202 F. to produce a raflinate of .804 V. G. C. and 1.98 carbon residue. This raflinate was then deresined with 6.2 volumes ofpropane at a temperature of 148 F. to produce a resin fraction corresponding to 21.1% of the residuum and having a viscosity of 357 S. S. U. at

24.4% of the residuum and had a viscosity of 569 S. S. U. at 210 F., a carbon residue of 4.2

'and a V. G. C. of .810. It will be noted that although the yield and viscosity are both considerably higher by my process, both the carbon residue and the V. G. C. are even better than 10 for the alternate process. If the alternate product were reduced to give a viscosity of 569 S. S. U. at 210 F., the yield would be still lower and the carbon residue and V. G. 0. even worse in relation to my product. These data illustrate the effectiveness of my method of processing on thequality of the resin fraction in the finished oil.

of 1000 seconds Saybolt at 210 F. from 8. Brad ford cylinder stock were treated with a 3.4:1 phenol ratio at 240 F. in a continuous tower to yield 24% of an 8.8 gravity extract and 76% of a 23.1 gravity oil having a viscosity at 210 F. of 768, a. carbon residue of 3.5% and a V. G. C. of .810. This ramnate when blended with the deresined cylinder stock markedly improved the yield of low V. G. C. 011. v

I have already referred to the improved clay yields obtainable byseparately claying the resin fraction into which substantially all of the color bodies are concentrated. To specifically illustrate this process, a partially refined 26.2 A. P. 'I.

gravity lubricating oil having a viscosity of 148 seconds Saybolt at 210 F. and a Tag Robinson color of 2 dilute was separated by means of pro- TABLE IV .En-lcr or Susan: TBIATMINT'ON QUALITY or HnvrFmcriou I Allegheny cylinder stock 'API gravity.'.

ssu vis., 210 F 201 v. o. o .818

Phenol treating Volume percent solvent 163 Temp. F.,' top 202 Temp. F., bottom.- 175 Vol. percent water injected 10. 6 Propane dereeinlna Phenol treating a! reeim 0 Bee Ta] le Ra nate Extract a I) VOLPOIOBHL... 86.9 VoL ercent. 13.1 AP 26.7 AP 10.7 V/2l0 180. O.R., ercent.. 1.98 V. G. .804

Propane iemining Vol. cent 0:. 620 Tem IffT..." 14.8

Dereeined oil Re -Ins Resin ralfinate Vol. reent 75.6 65.7 based on char e Vol. pereent..f24.4(21.27 based on charge) Vol. percent.-'24.1 ased on cha e AP I?f 21.4 g AP'I -4246 a "AP .1 (b m V/210 141.2 V/2l0.-;. 357 V/210 0 O R ,perocnt. 1.22 C-.' -,pereent-1 3. ,percent- 4 2 While phenol extraction has been described in my preferred examples, it should be understood that acid treating in propane or naphtha solution may be advantageous under certain circumstances. selective solvents than phenol may be used. The particular operating conditions for the acid treating or solvent extraction can readily be determined by preliminary experiments, but in all cases they will be more severe on the resin fraction than they would on the type of oils for which said processes have heretofore been employed. A feature of this invention is the use of these oil refining processes on resins under more severe oonditionsthan they have hereto- 5 fore been used in connection with heavy oils. It is difficult if not impossible to obtain high V. I. oils with reasonable yields by the solvent extraction of these heavy cylinder stocks, but by fractionating these cylinder stocks and treating the resins under more severe conditions than the oil fraction, I have succeeded in not only obtaining the desired high V. I.s but have also obtained unexpectedly high yield V. G. C. relationships.

For instance, dewaxed resins having a viscosity 7 It should also be understood that other 55 with a clay yield corresponding to 3.6 barrels pane at temperatures of 160 and F. into a A. P. I. gravity 27. 3 ViSCOSity at F seconds 115. 3 Tag Robinson color 1% Vol. percent of charge 86. 3

and a heavy oil having the following characteristics:

A. P. I. gravity 20. 3

When the original stock was percolated in. naphtha through Attapulgus clay it was brought .to a color of 1 Tag Robinson with a clay consumption corresponding to filtering 10.8 barrels of oil per ton of clay. When the resin fraction, i. e. the 20.3 A. P. I. gravity fraction, was filtered in naphtha solution through Attapulgus clay,

of oil per ton of clay, and when this clayed oil was blended back with the deresined oil, a color of 1 Tag Robinson was obtained on the blend. The yield of 3.6 barrels per ton of clay for filtering the resin fraction corresponds to an over-all yield oi 26 barrels of blended oil per ton of clay used. Thus by separating the original oil into a light fraction and a heavy resin-containing fraction in propane solution, it is possible to show an increase in yield on decolorizing the oil from 10.8 barrels per ton to 26 barrels per ton.

Table V presents data or a modification or my process wherein the dewaxing precedes the deresidue was reduced to 0.96. This raflinate was then percolated through Attapulgus clay with a yield of barrels per ton to give a color 01 2% Tag Robinson or about 6 N. P. A. and essentially no change in carbon residue.

When these two percolated oils were blended in the proportions in which they were produced, the resulting oil corresponded to 80.4% of the cylinder stock, the dewaxing loss having been resining and separate treatment of resins and de- 10 13.5% and the loss to extract by solvent treating resined oil respectively.

6.1%. The finished oil had a carbon residue of TABLE V Dewazed oil Dereeined oil, percent- 74.0 API 25.9

Solvent treating 338? Solvent treating 84 solvent 240 F. 9.7 a solvent 218 F. 11.4 a water injection water inlectlon Raflina wit as Extract percent 3.0 Extract psmmnnu--. 3.1 Raflinate an: 70:0 up .1 API..'. as API. 1.3 API zas Vin. 0 1 768 Visill0 F 126.2 0. u 3.5 1.0 Percolation ercola on 40.0 BIT 180 F.

API 26.9 Visi4'2l0" F 1%.5 o. 1.0

Bland finished oil All percentages are volume percent.

The resin fraction was treated in a countercurrent tower with 338% phenol and 9.? water was injected at the bottom of the tower for refluxing. The raflinate from this process was 75.9% of the resin charge of 9.5% of the original cylinder stock. This rafilnate had a viscosity of 768 seconds Saybolt at 210 F. and a carbon residue of 3.5. It was then percolated in naphtha. solution through Attapulgus clay to a color of 1 Tag Robinsonor about 8 N. P. A. with a clay yield of 3.2 barrels per ton. The finished resins then had a viscosity of 610 seconds Saybolt at 210 F. and a carbon residue of 2.4. Although this is an unusual product itself, it is of particular advantage when blended with the separately treated and percolated deresined oil.

The deresined oil was treated with only 84% solvent, as compared with 338% used on the resins, and the yield of 95.8% based on the charge, or 70.9% of the' original cylinder stock. The viscosity was reduced only slightly (to 125.2 seconds Saybolt at 210 F.) while the carbon 1.07, which is less than of the viscosity at 210 F., and the V. G. C. was 0.807. It is particularly noteworthy that the heaviest 12% of the finished cylinder stock has a low carbon residue for the viscosity and a viscosity gravity constant which is better than that of the main portion of the bright stock.

While I have described my invention in detail, the specific examples hereinabove set forth are illustrative of my invention and will teach those skilled in the art how to practice the invention, but it should be understood that I do not limit myself to any details except as defined by the following claims which should be construed as broadly as the prior art will permit.

I claim:

1. The method of refining a petroleum oil for the production of improved lubricating oils which comprises fractionating a residual lubricating oil stock containing uncracked heavy paraflinic components and resins into at least one viscous oil fraction having a viscosity at 210 F. below 300 seconds Saybolt and a resin fraction having a viscosity at 210 F.- or morethan 300 seconds Saybolt, diluting, the resin fraction with a hydrocarbon diluent heavier than propane but lighter than the removed viscous oil fraction, contacting the diluted resin fraction with clay in the absence of the separated viscous oil fraction, separately treating said-viscous oil fraction for improving its color and quality and blending at least a portion of the clay contacted resin fraction with said separately treated viscous oil traction in order to improve the quality of said viscous oil fraction.

2. The method or refining a petroleum oil for the production of improved lubricating oils which comprises iractionating a residual lubricating oil stock containing uncracked heavy paramnic components and resins into at least one viscous oil traction having a viscosity at 210 F. below 300 seconds Saybolt and a resin traction having a viscosity at 210 F. of more than 300 second Saybolt, diluting. said resin fraction-with naphtha, treating said diluted resin fraction with clay in the absence of said separated viscous oil fraction, treating said separated viscous oil fraction in the absence of the resin fraction to improve its color, stability and viscosity gravity constant, and blending at least a part of said separately clayed resin fraction with said separately treated viscous oil traction for improving the quality thereof.

HENRY 0. FORREST.

CERTIFICATE OF CORRECTION; Patent No. 2,255,285. September 9, 19141 HENRY o. FORREST.

It is hereby certified that error appears in the printed specification of the above numhered patent requiring correction as follows: Page 1;, Table II, u.nder the heading PHENOL TREATING" insertthe following Vol. percent solvent 195 Temp. F. top-" 207 Btm 170 Vol. percent water injected---- 10.0

sametable, under the heading "PROPANE DEWAXING", second item, for "5?" read- 57 same page )4, first column, line 1.1. from bottom; for "2.1 propane" read --2:l propane-; page 5, T ble III, lower left-hand side thereof, under the heading "Raffinate", for the third andfourth items W210 28-6 d -v/21o 91M,

page 8, first column, line 2, claim 1, for "or" read --of--; and that the said Letters Patent should be read with this correction therein that the same-may conform to the record of the case in the Patent Office.

Signed and sealed this 28th day of October, A. D. 1914.1.

Henry Van,Arsdale, (Seal) Acting Commissioner of. Patents.

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