US3228870A - Treatment of asphaltic crude oils - Google Patents

Description

Jan. 11, 1966 Filed Dec. 14, 1964 PENETRATION, IOOG/ SEC /77 "F 90 I00 H0 120 I I I I I I BY A. c. PITCHFORD 3,228,870

TREATMENT OF ASPHALTIC CRUDE OILS 3 Sheets-Sheet 1 F,MM/IO N N (20 O N O O O PENETRATION,IO0G /5 SEC /77 o l l l l l l l l l l o 2 4 6 a 10 12 14 I6 18 2o VOL. =7 n-HEPTANE IN ISOPROPANOL 'ISOFROPYL ALCOHOL D-ISOBUTANE INVENTOR. A. C. PITCHFORD y af 7 A T TORNEVS l l l H I SOFTENING POINT, R$B,F

FIG. 2

1955 A. c. PlTcHFoRD 3,

TREATMENT OF ASPHALTIG CRUDE OILS Filed Dec. 14, 1964 3 Sheets-Sheet 2 l l I l I I I 3 4 5 6 7 8 9 IO SOLVENT-OIL RATIO FIG. 3

x-|o7 RED WASH CRUDE 220- 5/1 SOLVENT RATIO 0 3 /0 RED WASH cRuDE 200- mm SOLVENT RATIO LL :1 -1o7 RED WASH CRUDE A RANGELY-RED WASH SYNTHETIC BLEND U 5/| SOLVENT RATIO I NVEN TOR.

I I I A.C. PITCHFORD l I l 2 3 4 BY VOLUME =7 WAT ER FIG. 4 (($077 A TTORNEVS Jan. 11, 1966 A. c. PITCHFORD 3,228,870

TREATMENT OF ASPHALTIC CRUDE OILS Filed Dec. 14, 1964 3 Sheets-Sheet 3 SOLVENT-OIL RATlO TO YIELD 9O PEN. ASPHALT T 4 I l l l VOLUME 7 WATER REQUIRED F/G. 5

22 SEPARATOR MALTENES-OIL INVENTOR 1 (MIXER b 3| FRACT'ON A.C. PITCHFORD ASPHALTENES A TTORNE VS United States Patent O 3,228,870 TREATMENT OF ASPHALTIC CRUDE OILS Armin C. Pitchford, Bartlesville, Okla, assignor to Phillips Petroleum Company, a corporation of Delaware Filed Dec. 14, 1964, Ser. No. 417,983 6 Claims. (Cl. 208-45) This application is a continuation-in-part of application Serial No. 128,171, filed, July 31, 1961.

This invention relates to the production of an improved hydrocarbon feed stock for the production of motor fuel. In one aspect it relates to the production of asphaltic, and resinous fractions from asphalt containing crude oil. In another aspect it relates to a relatively simple and economical process for separation of asphaltic, resinous and oily materials from crude oils containing these materials with the production of paving quality asphalt and improved quality feed stock for production of motor fuel.

These improvements include increased yields, lower carbon residue and a reduction in vanadium, nickel and iron contents of the oily fraction.

It is well known in the crude oil processing art that the asphaltenes and resins tend to produce coke during cracking and hydro-treating asphalt and resin-containing oils. It is also known that asphaltenes and resins are aromatic type components of crude oils. Thus, removing both of these aromatic components from asphalt-containing crude oils, results in the production of a superior charge stock for ultimate motor fuel production. The efiicient utilization of asphaltic crude oils or residual fractions thereof depends upon reducing their viscosity and minimizing the yield of residual product or increasing as much as possible the yield of motor fuel production stocks. By treatment of asphalt-containing oils with pentane the asphalt content is reduced and the viscosity of the extract phase is improved. However, large volumes of pentane or other closely related hydrocarbon solvents are required. The total volume of such solvent hydrocarbons can be reduced by raising the temperature and pressure of the treating operation. At temperatures approaching the critical temperature of pentane asphaltenes are precipitated along with a portion of the resin content of the oil to yield a high melting pitch which is more easily handled than dry asphaltenes which are precipitated at room temperatures. Such high temperatures require high operating pressures and accordingly expensive high pressure vessels and piping all of which contribute to high capital investments.

Paving asphalts are prepared by several methods, (1) by vacuum reduction, (2) vacuum reduction with air blowing, and (3) solvent extraction using normal butane, isobutane or propane. The use of propane or the butanes yields a high quality extract oil suitable for catalytic cracking feed stock for the production of motor fuel blending stocks. The propane or butane extract is essentially a paraflinic oil containing low concentrations of vanadium and nickel metals. However, initial investments for such processes are high because high pressure equipment is required. Also vacuum reduction requires low pressures and high temperatures. Steam costs are high because large volumes of steam are required in the vacuum operation. In many cases of vacuum reduction of asphalt-containing oils paving asphalt cannot be produced without slight or excessive cracking of the asphaltic constituents.

An object of this invention is to provide a process for the separation of asphaltic materials suitable for use as paving asphalts with the simultaneous production of oils suitable for use in catalytic cracking for the production of improved gasoline blending stocks. Another object of this invention is to provide such a process which is relatively simple to operate. Yet another object of this invention is to provide such a process for the production of paving asphalt and cracking stock which avoids need for use of high pressure equipment. Still other objects and advantages of this invention will be realized upon consideration of the accompanying disclosure.

FIGURE 1 is a curve showing relation of n-heptane content in solvent isopropanol on penetration of asphalt produced from Texas topped crude oil. FIGURE 2 shows curves comparing penetration of asphalts prepared from Texas crude oils using isopropyl alcohol (isopropanol) and isobutane as selective solvents. FIGURE 3 is a curve showing relation of solvent-oil ratio to penetration of asphalt of a Rangely, Colorado, topped crude oil using isopropyl alcohol as solvent. FIGURE 4 shows curves illustrating the effect of water in isopropanol on control of penetration of asphalt from Rangely, Colorado, crude oil. FIGURE 5 is a curve showing the water content required in isopropanol to produce penetration asphalt from Rangely, Colorado, topped crude oil at various solvent (isopropanol-water) ratios at 175 to 180 F. FIGURE 6 is a flow diagram showing arrangement of equipment for carrying out an embodiment of this invention. FIGURE 7 is a flow diagram showing arrangement of equipment for carrying out another embodiment of this invention.

When it is desired to produce from an asphalt-containing oil an oil free of asphaltic materials, such as a lubri eating oil stock, my solvent extraction system is particularly appropriate, because it leaves very little residual oil in the asphaltic phase. In other words the yield of the oil fractions is high. Furthermore, my process requires lower volumes of solvent than prior art processes, and it can be operated at atmospheric pressure and at lower temperatures than previously employed. If the purpose of the operation is to obtain a paving asphalt product, I am able to adjust the operating conditions to product an asphalt meeting paving specifications. I will now describe and illustrate my invention from the point of view of the operating conditions which give optimum results. Control of the process depends chiefly on the solvent additives which are used with the propyl alcohol (normal propyl alcohol, isopropyl alcohol) to, first, increase solvency or solvent power of the alcohol and, second, to decrease the solvent power of the alcohol. These two categories are herein described and illustrated separately.

The employment of an additive to increase the solvent power of the alcohol is particularly beneficial when treating a crude oil containing from about 2 to less than 8 percent of penetration asphalt, or an asphalt-containing fraction of such crude oil. Such a crude oil or fraction thereof is treated with a solvent in a solvent-oil volume ratio in the range of about 4 to about 20, the solvent comprising about 5 to 20 volume percent of a normal paratfin hydrocarbon containing from 5 to 15 carbon atoms per molecule of the paraflin hydrocarbon, and the remainder of the solvent being isopropanol or normal propanol, that is isopropyl alcohol or normal propyl alcohol, at a temperature within the approximate range of to F.

This embodiment of my invention is particularly adapted to the treatment of asphaltic crude oils containing less than 7 percent of 100 penetration asphalt. Such a crude oil is a West Texas crude oil. Ordinarily such a crude oil is topped, that is, fractions boiling up to and through the gas oils are removed leaving a thick oilasphaltic residue which in the refining art is termed topped crude.

It is frequently very diificult to produce paving asphalt of acceptable specifications from crude oils by vacuum reduction because of limitations of commercial units such as temperature and pressure. Vacuum reduction of such low asphalt content crude oils frequently results in cracking'of the residual asphaltic material. The presence of cracked material in asphalt usually makes such material unacceptable for paving uses.

In some instances when processing low asphalt content crude oils for the production of paving asphalts, propane, isobutane or normal butane extraction of the topped crude can be employed. Propane extraction requires pressure vessels because of the very high vapor pressure of propane. When using isobutane or normal butane, high solvent-to-charge oil ratios are ordinarily required for the production of acceptable paving asphalt. Unmodified propanol or isopropanol can be used similarly. However, when using propanol or isopropanol, solvent requirements may also ,be excessive as illustrated in the following table:

EXAMPLE I Table I .--Extractin of Texas vacuum residue with anhydrous isopropyl alcohol the ratio of 10 to l, solvent to oil, that a suitable paving asphalt was obtained. Thus, the use of only 10 volumes of solvent per volume of charge in contrast to 60 volumes of solvent per volume of charge oil illustrates the marked advantage of using normal heptane with the isopropanol.

The effect of the hydrocarbon additive on the extracting power of isopropanol is illustrated graphically in FIG- URE 1. From this figure it is noted that in order to produce asphalts having penetrations from 85 to 100 requires the use of from about 12.6 to 13.4 volume percent of normal heptane in the isopropanol when using a solvent-oil ratio of 10 to 1 at about 176 F. In the following Table III is given the minimum and maximum as well as the optimum volume percent normal heptane Asphalt Extraction Run N0. Solvent Solvent temperature,

ratio F. Yield, wt. Pen., R dz 13,

percent 77 F. F.

IsopropanoL 10/1 178 58. 4 Too s0it 91 d0 15/1 178 46. 7 a d0 97 do /1 178 51.0 .d0 93 a. do /1 178' 60.5 d0 101 (10 /1 178 31.0 110 do /1 178 28. 9 94 115 In the runs illustrated in Table I isopropanol (isopropyl alcohol) was used in the solvent-oil ratios given to extract the vacuum residue of a West Texas crude oil. Only suflicient pressures were employed to maintain the solvent in the liquid phase. It will be noted from the data in this table that a 60 to l solvent-oil ratio was required to yield an asphalt having a penetration of 94 at 77 F. The smaller or lower solvent-oil ratios yielded asphalts too soft for paving purposes.

In the following Table II are given results illustrating the use of the solvent isopropanol containing paraffinic to be used with isopropanol for the production of the stated penetration grade asphalt when using a solvent-oil ratio of 10 to 1 and a temperature of about 176 F. It is to be understood that with solvent-to-oil ratios higher than 10 to 1, up to 20 to 1, lower concentrations of nparaffin in the solvent can be used to extract the desired grade of asphalt (85 to 100 penetration) and with lower solvent-to-oil ratios than 10 to 1, down to 4 to 1, higher concentrations of n-paralfin can be used to produce the desired paving grade of asphalt. Also the optimum conditions of operation for any given feed will vary some hydrocarbon additives to increase the solvent power of 45 with the particular characteristics of the feed.

the isopropanol.

EXAMPLE 'II T able Il.Extracti0n of Texas vacuum. residue with isopropanol containing a hydrocarbon additive It will be noted in Table II, that in run 7 which employed only 75 volume percent normal heptane in the isopropanol, the penetration of the produced asphalt was 255, which value obviously is too high for grades of paving asphalt normally in demand. In run 8, 13 volume percent n-heptane was employed with the isopropanol and an asphalt having a penetration of 98 was produced. It is pointed out that this run 8 yields an asphalt quite similar to that asphalt produced in run 6 illustrated in Table 1. Thus, by the use of 13 volume percent of such a normal paraffinic hydrocarbon as normal heptane with the isopropanol, the entire or complete solvent being used in In FIGURE 2 is a curve showing the relation between the softening point, by the ring and ball method in degrees F. and the penetration at 77 F. of the asphalts of runs 7, 8, 9, and 10 in Table II.

Other paraflinic hydrocarbon additives can be used in place of normal heptane, illustrated above, such other hydrocarbons being hexane, octane, nonane, decane, pentane, cyclohexane, kerosene, naphtha or other distillate fraction, preferably having a boiling point or range near the boiling point of isopropyl alcohol at about atmospheric pressure. This boiling range of the paraffinic hydrocarbon material can be extended somewhat if sufficient pressure is imposed on the system to maintain the hydrocarbon in the liquid phase at the operating temperature.

The second embodiment of my invention involves the use of an additive to decrease the solvent power of the propanol and isopropanol. This embodiment is particularly adapted to treating crude oils which contain from about 8 percent to about 80 percent of 100 penetration asphalt, or a fraction of such crude oil. In this case the crude oil or the fraction thereof, is treated with a solvent in the solvent-oil-ratio in the range of about 4 to 20 volurnes of solvent per volume of oil. This solvent comprises from about 0.75 to about 4.5 volume percent water and the remainder of the solvent is isopropanol or normal propanol, the treating temperature being in the range of about 175 F. to about 180 F. Topped crude oil fractions from Monagas (Venezuela) crude oil, some West Kansas and some Southern Oklahoma high asphalt crude oils and Rangely (Colorado) intermediate asphalt content crude oil are operable with the process of this invention in which the solvent power of the alcohol is reduced with water.

The production of paving asphalt from crude oils or topped crude oils containing large amounts, that is, from 8 to 80 percent asphalt, of 85 to 100 penetration, presents a problem which requires careful control, usually a reduction in the solvent power of the extraction solvent. In

the following Table IV are given data illustrating the 'ter.

EXAMPLE III T able I V.Preparation of asphalt from Monagas topped crude by isopropyl alcohol extraction, with and without water Asphalt Asphalt properties Run No. Solvent ratio Temp, yield, wt F. percent Pen., R&B, 77 F. F.

5/1 178 36. 7 4 182 7.5/1 179 35. 3 2 191 15 180 30. 0 219 120 49. 7 83 119 110 51. 92 117 5/1 (1% HzO) 180 39.7 13 163 5/1 (2% H2O 178 42. 7 21 149 5/1 (4% 1120)---- 180 49. 2 33 136 5/1 (4.5% H20 181 51.9 42 131 (5% H 184 58. 9 199 100 1 (13% NO 178 30. 2 0 218 In Table IV, it is noted that in run 22, 13 percent normal heptane was used with isopropyl alcohol at a temperature of 178 F. This run produced a very low yield percent of asphalt of 0 penetration at 77 F. Thus, the use of this amount of normal heptane with the isopropanol yielded an asphalt far too hard for use as a paving asphalt.

Crude oils such as those from Rangely, Colorado, contain from about 8 to 12 percent of 85 to 100 penetration asphalt. In addition, the asphalt produced from this crude oil contains a microcrystalline wax which is associated with the asphaltene fraction of the asphalt. The crude oil appears to be deficient in a middle-rangemo- 6 lecular weight fraction (1000-2000 M.W.) commonly referred to as resins. These composition variations make the control of a solvent extraction process very difficult since with propane, a slight change in temperature or in 5 solvent-oil ratio produces a magnified change in yield and grade of asphalt.

In the following Table V are given data illustrating the marked change in 77 F. penetration of an asphalt produced in the propane extraction of a Rangely topped crude oil fraction with small temperature changes. When the temperature of extraction was increased from 191 to 196 F. the penetration increased from 13 to 48, and a further increase in extraction temperature to 204 F. produced an asphalt having a penetration of 324. Thus, it is noted that slight changes in temperature with the propane-to-oil ratio remaining substantially constant yielded asphalts having very great diiferences in penetration. In an operation using propane as the solvent for the production of paving asphalt temperature control would be very difficult. 2

EXAMPLE IV Table V.Pr0pane fraction of 28% Rangely topped 3 crude S/O ratio Asphalt, vol.

Temperapercent Penetration ture, F. 77 F.

EXAMPLE V Table VI.16% Rangely reduced topped crude Asphalt Run Solvent S/O ratio Tempera- No. ture, F. Yield, Peneweight tration percent of crude Isopropyl 3/1 179 10. 6 186 alcohol.

In the following Table VII are given data showing the quality of asphalt produced when using anhydrous isopropanol with a blend of Rangely, Colorado, and Red carbon tetrachloride and the oliensis spot test.

These data of Table VII are plotted in the form of a curve which is shown in FIGURE 3. This curve shows that the 85-100 penetration grade asphalt lies in the vertical portion of the curve and solvent-to-oil ratio to produce specification.penetration of 85 to 100 would be very difilcult to control. This difiiculty can be easily overcome by using aqueous isopropanol as a solvent in place of the anhydrous isopropanol. In Table VIII are given the volume percentages of water used with the isopropanol and the solvent-to-oil ratios given represent the total solvent, that is, the isopropanol plus water.

EXAMPLE VII Table VIII.--A queous isopropanol extraction of Rangely topped armies to produce paving asphalt The several categories of solvent-to-oilratios as shown in Table VIII are plotted as curves in FIGURE 4. These curves are drawn to illustrate the relation between the volume percent of water in the solvent and penetration at 77 F. It will be noticed that in all of these curves there is an appreciable horizontal component, that is relative to the water content of the solvent in the range of penetration of 85 to 100 with the exception of the upper curve. Thus, in view of these relatively large horizontal components illustrating the volume percent water in the isopropanol extractant, the control of such an operation is relatively simple. As will be well understood by those skilled in the art, the control of the volume percent of water in the isopropanol is much easier than to control temperatures of the extraction column vw'thin, for example, 1, 2, or 3 degrees.

Cross plotting of the data illustrated in FIGURE 4 and given in Table VIII is illustrated in FIGURE to show the volume of water necessary to produce 90 penetration asphalt at various solvent-oil ratios from similar charging stocks.

The 90 penetration values from curves 1, 2, and 3 only are used in plotting the curve illustrated in FIGURE 5. This cross plotting of the data (FIGURE 5) shows that the water content of the isopropanol varies from about 0.75 to about 4.5 volume percent at solvent-to-oil ratios from about 5 to 1 to 17.5 to 1, respectively, at extraction temperatures between 175 and 180 F.

As mentioned hereinbefore Rangely crude oil contains small quantities of micro-crystalline wax which tends to degrade the specification properties of asphalt prepared by vacuum reduction of propane extraction. These prop erties include penetration ratio, solubility of asphalt in By using aqueous isopropanol these properties are improved as shown in the following example. In the following Table IX are given paving asphalt specifications sforthe State of Oklahoma for comparison with paving asphalt produced by vacuum reduction and isopropanol extraction of the identical topped crude charge "stock.

While the data given above illustrating the operation of this invention involves use of isopropanol, I disclose the use of normal propanol as an equivalent of the isopropanol in all respects; However, relative to cost of the material isopropanol is preferred because it is less expensive to purchase commercially than is the normal propanol.

The apparatus required for carrying out the operations of this invention is relatively simple as will be noted in reference to FIGURE 6. The crude oil, or strictly speaking, topped crude oil passes from a source, not shown, through a conduit 1 into an extractor vessel 2. This extractor can be countercurrent, liquid-liquid contacting column or it can be merely a mixing vessel in which the solvent aqueous isopropanol and the asphaltic oil are mixed. In such a mixer upon addition of the isopropanol and asphaltic oil contacting is achieved by use of a stirring device of any suitable type. However, for most operations, a countercurrent extraction operation is preferred. Thus, from extractor 2 the oily material in solution in the aqueous isopropanol is removed through a conduit 3 and is introduced into a still 4. In this still the aqueous isopropanol is distilled from the oil, the oil being removed from this vessel through a conduit 5 for such disposal as desired. The aqueous isopropanol vapors are removed from still 4 through a conduit 6, condensed in condenser 7 and condensate is passed on through a conduit 9 to a run storage vessel 10 and thence through a conduit 11 to the extractor 2. Make-up aqueous isopropanol is added to the system through a conduit 8. Since the aqueous isopropanol is specifically lighter than the asphaltic oil being treated the solvent is introduced at a level near "the bottom of the column. Upon introduction into vessel 2, this specifically light aqueous isopropanol passes upward in countercurrent contact with the relatively heavy and down-flowing asphaltic oil. This extractor vessel can be provided with suitable liquidliquid contact promoting apparatus. The dissolved oil and solvent pass from extractor 2 through an overhead conduit 3 and this extract phase is introduced into still 4. The asphalt containing phase with a very minor proportion of solvent is withdrawn from extractor 2 through a conduit 12 and is passed into a still 13. In this vessel the small amount of solvent is removed by distillation through a conduit 14 and'these vapors are added to those from conduit 6 prior to passage to condenser 7. The hot solvent-free asphalt is removed from still 13 through a conduit 15 for such disposal or such use as desired. Relative to operations of stills 4 and 13 refluxing and reboiling operations a're'not diflicult because there is contopped crude oils disclosed hereinabove it Will then be necessary to dilute the original topped crude material with 'pentan'e within a temperature range of from about 60 to about F. using a solvent-'to-oil ratio of about '5 to 1 to 15 to 1 under pressures of from about 1 to 2 atmospheres. This portion of the process, however, is operable over a greater temperature range such as from about 50 to about 450 F. when using a solvent-to-oil ratio by volume of 2 to 1 to about 100 to 1 and at pressures varying about 1 to about 50 atmospheres. As examples of the operation of the pentane separation portion of this operation a charge of Wafra (Kuwait) vacuum reduced crude oil was slurred with anequal volume of pentane. This slurry was then added to an additional 9 volumes of pentane, the mixture stirred for an hour and allowed to settle for about 16 hours. The pentane soluble material was decanted 'and filtered. The precipitated asphaltenes were washed with approximately 5 volumes of fresh pentane. These washings were added to the pentane soluble material and the pentane from the entire mixture was recovered by fractional distillation.

In the following Table X are given four sets of run data using pentane for treating asphalt-containing oil for the separation of an asphaltenes product.

EXAMPLE IX Table X .Pentane extractions of Wafra 1025 F residuum Run No A-l A-Z A-3 A-4 Wt. of asphalt, lbs 38. 26 36. 38. 0 38. 0 Vol. of aphalt, gals 4. 52 4. 26 4. 5 4. 5 Vol. n-pentane, gals. 45. 9 44. 9 44. 6 45.1 Solvent ratio 10. 1 10. 5 9. 9 10. 0 Temperature, F 78 80 85 86 Settling time, hrs 16 16 72 48 Filtrate plus lfl-gal. wash, gals" 52. 1 53. 3 52. 5 52. 5 n-CE evaporation loss, gals 3.8 1. 6 2. 1 2. 6 Yields:

Asphaltenes, lbs 5. 47 5. 62 5. 37 6. 23

Asphaltenes, wt. percent 14. 8 15.6 14.13 16. 3

Maltenes, lbs 20. 84 33. 39 29. 88 33. 2

Maltenes, wt. percent 54. 4 92. 2 78. 7 87. 5 11-0 recovered, gal 43. 7 50. 4 47.0 47. 0 n-O loss in stripping, gal 8. 4 2. 9 5. 5 5. 5

In these four runs the solvent-to-oil ratio varied from 9.9 to 10.5 and temperatures of treating varied from 78 to 86 F. It will be noted that from 5.37 pounds of asphaltenes to 6.23 pounds of asphaltenes were produced from 36 to 38 pounds of original Wafra residuum. In Example A-l from 38.26 pounds of asphaltic charge stock, there were recovered 5.47 pounds of asphaltenes and 20.84 pounds of maltenes. This quantity of maltenes plus the quantity of asphaltenes total only 26.31 pounds; there being an appreciable loss. This loss was in the maltenes fraction because some of the maltenes were carried into other parallel runs with pentane used for washing. In the total operation, ten individual parallel runs were made using a total weight of asphaltic feed stock of 375.39 pounds. There was recovered from the ten parallel operations 54.69 pounds of asphaltenes and 320.7 pounds of maltenes. These two products totaled 375.39 pounds, the exact weight of the asphaltic material used as charge stock. This 100 percent recovery of the combined maltenes and asphaltenes is relatively simple because of the extremely high boiling points of these materials.

The asphaltene separation by way of pentane precipitation is carried out in an apparatus as illustrated in FIG- URE 7. The topped crude material is fed into a mixer 22 by way of a conduit 21. Normal pentane as solvent enters the mixer 22 by way of a conduit 23, from a source to be disclosed hereinafter. After sufi'icient and thorough mixing in mixer 22 the mixture is passed by way of a conduit 24 to a separator vessel 25 in which the precipitated asphaltenes are separated from the pentaneasphaltene liquid phase. The separated asphaltenes are removed from separator 25 through a conduit 26 for a subsequent washing step or for such use as desired. The liquid maltene-containing fraction is removed from separator 25 through a conduit 27 and is passed to a still 28 for recovery of the solvent pentane. This still is operated under such temperature and pressure conditions as to separate normal pentane from the heavy oily maltene fraction. Vaporous pentane leaves still 28 by way of a conduit 29, is condensed in condenser 30 and condensate is passed on through the before-mentioned conduit 23 for reuse in mixer 22. The maltene-oil fraction is withdrawn through a conduit 31 from the kettle section of still 28. Make-up pentane as required is added to the system through a line 32 from a source, not shown.

The heavy maltene-oil fraction withdrawn from the kettle section of still 28 through a conduit 31 can, if desired, be treated in the system illustrated in FIGURE 6 of the drawing. If it is desired to separate and to recover a resin fraction from this maltene fraction then the process described and illustrated hereinabove relative to FIG- URE 6 is employed. By treating the maltenes-oil fraction free from asphaltenes in the apparatus and according to the system of FIGURE 6, there will be produced a resin fraction which is removed through conduit 15 from the kettle section of still 13. The oil fraction removed through conduit 5 is the same oil fraction removed through this conduit when the entire asphalt containing charge oil is treated according to the system of FIGURE 6.

While certain embodiments of the invention have been described for illustrative purposes, the invention obviously is not limited thereto.

I claim:

1. A process for simultaneously producing a paving grade asphalt and an oil suitable for catalytic cracking to produce gasoline blending stocks from an asphalt-containing oil in which the concentration of penetration asphalt is in the range of 2 to less than 8 volume percent which comprises the steps of:

(l) contacting said asphalt-containing oil with a solvent selected from the group consisting of n-propanol and isopropanol containing from 5 to 20 volume percent of normal parafli-n hydrocarbon of 5 to 15 carbon atoms per molecule;

(2) maintaining the volume ratio of solvent to oil in step (1) in the range of 4 to 20 and the temperature in the range of to F.;

(3) separating from the contacting a first asphaltenerich phase and a second asphaltene-lean phase;

(4) recovering from said first phase a paving grade asphalt; and

(5) recovering from said second phase an oil for catalytic cracking.

2. The process of claim 1 wherein said hydrocarbon is principally normal heptane.

3. The process of claim 1 wherein said asphalt-containing oil has been previously treated to remove a portion of the asphaltenes.

4. A process comprising contacting an asphalt containing oil with from 2 to 100 volumes of liquid pentane per volume of oil at a temperature within the range of about 50 to 450 F.; from this operation separating a liquid phase rich in pentane, containing a maltenes fraction, from an asphaltenes phase; recovering asphaltenes from this latter phase as one product of the operation; separating from said liquid phase a maltenes fraction containing from about 2 to less than 8 volume percent of 100 penetration asphalt; contacting the separated maltenes fraction at a temperature in the range of about 175 to 180 F. with a solvent selected from the group of solvents consisting of normal propyl alcohol and isopropyl alcohol and containing an n-paraifin of 5 to 15 carbon atoms in a concentration in the range of 5 to 20 volume percent; from this latter contacting step separating an oil phase rich in said solvent and a resin phase lean in said solvent; recovering oil from said oil phase as a product; and recovering resin from said resin phase as another product of the process.

5. The process of claim 4 wherein said solvent is principally normal heptane.

6. A process comprising contacting an asphalt contain-. ing oil with from 4 to volumes of a solvent selected from the group consisting of pentane and hexane per volume of oil at a temperature within the range of about to 450 F.; from this operation separating a liquid phase rich in said solvent, containing a maltenes and oil fraction in which the concentration of penetration asphalt is in the range of 2 to less than 8 volume percent from an asphaltenes phase, recovering asphaltenes from this latter phase as one product of the process; separating said solvent from said maltenes and oil fraction of said liquid phase; contacting the separated maltenes and oil fraction with a second solvent selected from the group of solvents consisting of normal propyl alcohol and isopropyl alcohol and containing a normal parafiin of 5. to 15 carbon atoms in a concentration in the range of 5 to 20 volume percent at a temperature of to F.; from this latter con tacting step separating an oil phase rich in said second solvent and a resin phase lean in said second solvent, recovering oil from said oil phase and recovering resin from said resin phase as additional products of the process.

No references cited.

ELBERT E. GANTZ, Primary Examiner.

Claims (1)

1. A PROCESS FOR SIMULTANEOUSLY PRODUCING A PAVING GRADE ASPHALT AND AN OIL SUITABLE FOR CATALYTIC CRACKING TO PRODUCE GASOLINE BLENDING STOCKS FROM AN ASPHALT-CONTAINING OIL IN WHICH THE CONCENTRATION OF 100 PENETRATION ASPHALT IS IN THE RANGE OF 2 TO LESS THAN 8 VOLUME PERCENT WHICH COMPRISES THE STEPS OF: (1) CONTACTING SAID ASPHALT-CONTAINING OIL WITH A SOLVENT SELECTED FROM THE GROUP CONSISTING OF N-PROPANOL AND ISOPROPANOL CONTAINING FROM 5 TO 20 VOLUME PERCENT OF NORMAL PARAFFIN HYDROCARBON OF 5 TO 15 CARBON ATOMS PER MOLECULE; (2) MAINTAINING THE VOLUME RATIO OF SOLVENT TO OIL IN STEP (1) IN THE RANGE OF 4 TO 20 AND THE TEMPERATURE IN THE RANGE OF 175 TO 180*F.;

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