US2686149A

US2686149A - Treatment of oil for removal of alkali metal salts

Info

Publication number: US2686149A
Application number: US203124A
Authority: US
Inventors: Jere C Showalter
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1950-12-28
Filing date: 1950-12-28
Publication date: 1954-08-10
Anticipated expiration: 1971-08-10

Description

10, 1954 J. c. SHOWALTER 2,686,149

TREATMENT OF OIL FOR REMOVAL OF ALKALI METAL SALTS Filed Dec. 28, 1950 HYDROGARB ON CONTAINING ALKALI METAL SALTS N INGORPORATOR 3 Lpnomus nrsn I9 N I HEATER nouns h 1 s -2i ii"!!! --sv4rbn4ron 23 sur use on.

mu usnu. snrs INVENTOR. Jere C. Showalfen,

A6 NT Patented Aug. 10, 1954 TREATMENT OF OIL FOR REMOVAL OF ALKALI METAL SALTS Jere C. Showalter, Baytown, Tex., assignor, by

mesne assignments, to Standard Oil Development Company, Elizabeth, N. J., a corporation of Delaware Application December 28, 1950, Serial No. 203,124

9 Claims. 1

The present invention is directed to a method for treating a hydrocarbon containing alkali metal salts to recover therefrom a substantially salt-free oil. In its more particular aspects, the invention has to do with the removal of alkali metal naphthenates and/or alkali metal sulfonates from hydrocarbons containing them to allow recovery of the naphthenates and sulfo mates and to produce a substantially salt-free oil.

The present invention may be briefly described as involving the formation of a mixture of a by drocarbon oil containing alkali metal salts with at least 10% by volume of water, following which the water-containing admixture is agitated vigorously to form an emulsion. The emulsion is then extracted with liquefied propane at a temperature in the range between 100 and 200 F. to form at least an oil phase and an aqueous phase. The propane may be removed from the oil phase to allow recovery of a substantially salt-free oil which may suitably be used as a feed stock for catalytic cracking operations, while the aqueous phase may have water removed therefrom to allow recovery of the alkali metal salt. When the alkali metal salt is an alkali metal sulfonate, the sulfonates may be recovered in improved yields and purity.

The feed stocks to the process of the present invention may suitably be sulfuric acid treated mineral oils, such as those used in the production of white oils. For example, these oils are exhaustively treated with strong sulfuric acid and then neutralized with an alkali metal hydroxide, such as sodium hydroxide. The neutralized oil may then form the feed stock for the present invention. Other acid treated and neutralized oils containing alkali metal sulfonates may also be employed in the practice of the present invention.

The invention is not restricted, however, .to such feed stocks and may be suitably used in removing alkali metal salts from neutralized sludges resulting from the treatment in propane solutions of lubricating oil fractions with sulfuric acid. The oils resulting from the distillation of crude oil and crude petroleum fractions, such as lubricating oil fractions, over alkali metal hydroxides which contain substantial .quantitles of alkali metal naphthenates are also suitable as feed stock to my process. Neutralized slop oils containing alkali metal sulfonates, such as sodium sulfonates, and alkali metal naphthenates may also be treated in accordance with the practice of the present invention to allow recovery of a substantially salt-free oil.

In practicing the present invention, it is essential that the water content of the oil containing either sulfonates and/or naphthenates have its water content adjusted so that the water content is at least 10% by Volume. If the water content is not adjusted, the salt content may be reduced but not lowered to the extent where substantially all of the valuable sulfonates are recovered or where substantially all of the salts are removed from the oil. If substantially all of the sulfonates are not removed from the oil, valuable materials are lost and the oil is degraded in quality. If substantially all of the salts, such as naphthenates and sulfonates, are not removed from the oil, the oil is largely unsuitable either as a fuel oil or as a cracking stock.

The present invention will be further 'L lustrated by reference to the drawing in which the single figure represents a flow diagram of a preferred mode of practicing the invention. In the drawing numeral ll designates a charge tank containing a hydrocarbon, such as a lubricating oil fraction, which has been treated with strong sulfuric acid for white oil manufacture and which contains an alkali metal sulfonate, such as sodium sulfo-nate. The oil containing sodium. sulfonates in tank H is withdrawn therefrom by line l2 to which is added by line I3 at least 10% by volume of water. The admixture of oil and water in line 12 is then discharged into an incorporator I l or other suitable mixing device, such as a centrifugal pump, a tank containing an agitator, and the like or other suitable mixing means wherein the admixture of oil and water containing alkali metal sulfonates is formed into an emulsion. The emulsified admixture is then withdrawn by line [5 and has added to it a suitable amount of pro-pane which is introduced by line It. The amount of propane employed will vary from about 2 volumes of propane per volume of oil up to about 10 volumes of propane per volume of oil. A suitable amount is approximately 6 volumes. The emulsion to which propane has been added in line l5 then passes through a heater ll wherein the temperature is raised to a temperature in the range between and 200 F. A temperature of F. gives entirely satisfactory results in separating sodium sulfonates. The propane, of course, is maintained in a liqueficd condition by application of suitable pressures. The heated mixture of propane and emulsifled oil is then discharged by line l5 into a separator vessel IS. The propane acts as a solvent and preferentially dissolves the hydrocarbon while the sodium sulfonates are dissolved substantially in the aqueous phase in separator 18 which is of suficient capacity to allow a residence time for separation by gravity of the admixture into at least an oil phase and an aqueous phase. For the purpose of this description wherein oil which has been treated for white oil manufacture and which contains sodium sulfonates is extracted with propane, an oil phase and an aqueous phase obtains. The oil phase is withdrawn from separator 18 by line it and dis charged thereby into a. distillation tower or other suitable separation means 20 to allow removal of propane from the oil. Conditions in distillation tower 20 are adjusted by heating means illustrated by steam coil 2! whereby propane is removed from the oil and discharged from tower 20 by line 22. A substantially saltfree oil is recovered from tower 20 by line 23 which may be used for further treatment with sulfuric acid. for white oil manufacture or may be recovered for use as a white oil it the oil has been exhaustively treated prior to treatment in accordance with the present invention.

The aqueous phase separated in separator i8 is withdrawn therefrom by line 2@ controlled by valve 25 and discharged thereby into an evaporator 26 which is a conventional type evaporator or evaporators and allows removal of water by line 2'5. The alkali metal salts, such as sodi um sulfonate, may be discharged from evaporator 26 by line 28.

When the oil in tank I i is a neutralized sludge resulting from the treatment in propane solution of lubricating oil fractions with sulfuric acid or a neutralized slop oil or a hydrocarbon fraction resulting from the distillation of a crude 3| controlled by valve 32, valve in line 2 4 being in a closed position, provided the amount of sulfonates and/or naphthenates in the aqueous phase is insufficient for economical recovery.

The invention will be further illustrated by reference to the following examples:

EXAMPLE I In this example in accordance with the present invention a 500 Vis. 100 F. Coastal lubrieating oil distillate was heated to 145 F. and then 7.8 volume per cent of oleum was applied. The sludge was drawn and the acid oil was blown with air to expel the sulfur dioxide and cause the pepper sludge to coagulate. The acid oil was then neutralized with aqueous sodium hydroxide, and the neutralized oil was emulsified with 10 volume per cent of water. The sulfonates were extracted from this mixture with 6 volumes of liquid propane at 150 F, These steps were repeated four times. After the fourth acid dump it was observed that the yield of sulfonates was so low that another acid application would not be profitable. Therefore, the oil was finished for white oil. After the fourth propane extraction, the oil still contained approximately 1.5 weight per cent of sulfonates. Since these sulfonates could not be washed from the oil with hot water alone, 10 volume per cent of 92% isopropyl alcohol was used along with the water. After this extraction the oil was steamed and dried and then percolated through to mesh Attapulgus clay to produce USP white oil. The quantity of materials used for each treat, and the yields obtained are given in the following table:

Table I EXTRAOTING SUFONATES WITH PROPANE Propane i Oil Chg. Water Crude S111 y Oll Oleum 011 Re- Sludge Re- Free Vi atei Extracted figi gg Charged Applied, covered, covered, gg g gggi gg ggggi Recovered, Oil Rig Treat, cc. Treat, cc. Grams 20, 000 l, 560 16, 600 4, 911 16, 600 I, 660 696 137 15, 000 16, 000 l, 560 12, 800 4, 713 12, 800 l, 280 l, 809 234 10,000 10, 000 l, 560 9, 000 2, 560 9, 506 950 l, 087 332 2, 000 4.. 9, 000 1 560 7, 640 2, 920 7, 640 764 115 480 I. 500

1 Contains sulfuric acid. 1 Contains 115 grams dry sulfonates.

oil or a fraction thereof over an alkali metal EXAMPLE II hydroxide, the amount of water employed is about 25% by volume. When such latter feed stocks are used, it may be desirable also to wash the oil-propane mixture after heating to a temperature in the range between 100 to 200 F. with further quantities of water. Also, when such feed stocks are employed, there is formed in separator it three phases rather than two phases. There is formed the oil phase, an intermediate phase, and an aqueous phase. The oil phase contains propane having the oil in solution. The intermediate phase contains substantially all of the salts or ashy materials and also asphaltic bodies, if present, while the aqueous phase may contain sodium sulfonates and/or naphthenates over and beyond that present in the intermediate phase. When such fractions form the feed stocks of the process of the present invention, the intermediate phase may be discharged from separator 18 by line 29 controlled by valve 30 while the aqueous phase may be discharged from the system by line 24 and line In order to illustrate the improvement of the present invention over the prior art processes a 500 Vis. F. Coastal lubricating oil distillate was treated with 3 successive '7 .8 volume per cent applications of oleum at F. The acid oil was air blown to expel the sulfur dioxide and coagulate the pepper slude. This acid oil was then neutralized with aqueous sodium hydroxide and the sulfonates extracted with one-half a volume of 50% isopropyl alcohol. The extracted oil was heated and blown with air to expel all water and traces of alcohol. The remaining oil was treated with two more applications of 7.8 volume per cent of oleum and then the sulfonates were extracted with propane as before. The residue oil was finished for white oil. v

A comparative analysis of the sulfonates obtained by these two processes is ven i t e following Table II, and a comparison of the sulfonate yield obtained by the two processes is given inTab1eIII."'

Table II ANALYSIS or CRUDE SULFONATES traction After Each 3d Acid Dump %;3?

Based on Oil Chgd., Lb./Bbl 32.;

11. Based on Oil Chgd., Wt. Percent .l 3.

It will be seen from the foregoing comparisons that the practice of the present invention allows the production of sulfonates containing lesser quantities of oil than the conventional alcohol extraction process. Furthermore, the practice of the present invention allows the obtaining of substantially greater quantities of sulfonates than the prior art processes.

In other operations in accordance with the present invention neutralized propane lube plant sludge resulting from the neutralization of sludge produced by sulfuric acid treating in propane solution of a lubricating oil fraction, a neutralized separator slop oil, and a blend of neutralized bottoms fractions from the distillation of naphtha, neutralized propane lube plant sludge, oil resulting from the distillation of a petroleum fraction over caustic, and a neutralized slop oil were treated by adjusting the water content to about 25%, following which the mixture was agitated to emulsify same and then admixed with 4 vols. of liquid propane at 150 F. to cause an extraction thereof. In the final separation stage a low ash content oil stream, an ashy residual material, and a water phase were recovered. The oil stream was then depropanized and tested. When the feed stock was the neutralized propane lube plant sludge, the content of salt or ash bodies was reduced by treatment in accordance with the practice or the present invention from 7,200 p. p. m. to 38 p. p. m. The neutralized separator slop oil was treated similarly and the ash or salt content was reduced from 30,000 p. p. m. to 60 p. p. m. The blend had an ash content of 13,880 p. p. In prior to treatment in accordance with the present invention. After treatment, the ash content of it was 43 p. p. m.

It will be seen from the foregoing examples that the present invention allows the recovery of high yields of high purity sulfonates. The process is adaptable to the recovery of naphthenates as well. It will also be obvious that the present invention allows the production of low ash or salt content oils which may be used as cracking stocks in catalytic cracking, or the oils having low ash content may suitably be used as fuel oils. It is well known that salts are deleterious in fuel oils because of the tendency of the salts to form slags in furnaces and also to clog burner openings.

The nature and objects of the present invention having been completely described and illustrated, what I wish to claim as new and useful and to secure by Letters Patent is:

1. A process for treating a hydrocarbon oil mixture selected from the group consisting of neutralized slop oils, neutralized sludges resulting from treatment of lubricating oil fractions in propane solution with sulfuric acid, neutralized bottoms fractions from the distillation of naphtha, oil resulting from the distillation of crude petroleum and its fractions over caustic, and neutralized acid oils resulting from treatment oflubricating oil with sulfuric acid containing an alkali metal salt of an organic acid selected from the group consisting of naphthenic and sulfonic acids which comprises forming with said mixture a second mixture containing about 25% by volume of water, agitating vigorously said water-containing admixture to emulsify same, extracting the emulsified admixture with pro pane in an amount in the range from about 2 volumes to about 10 volumes per volume of hydrocarbon oil at'a temperature in the range between and 200 F. to form at least an oil phase substantially free of alkali metal salts and an aqueous phase, separating said phases, removing propane from said oil phase and recovering an oil substantially free of salt of said organic acid.

2. A process in accordance with claim 1 in which the alkali metal salt is a salt of naphthenic acid.

3. A process in accordance with claim 1 in which the alkali metal salt is a salt of sulfonic acid.

4. A process for producing a hydrocarbon substantially free of salt of an organic acid which comprises forming a mixture of a hydrocarbon oil selected from the group consisting of neutralized slop oils, neutralized sludges resulting from treatment of lubricating oil fractions in propane solution with sulfuric acid, neutralized bottoms fractions from the distillation of naphtha, oil resulting from the distillation of crude petroleum and its fractions over caustic, and neutralized acid oils resulting from treatment of lubricating oil with sulfuric acid containing an alkali metal salt of an organic acid selected from the group consisting of naphthenic and sulfonic acids and about 25% by volume of water, agitating vigorously said water-containing admixture to emulsify same, extracting the emulsified admixture with liquefied propane in an amount in the range from about 2 volumes to about 10 volumes per volume of hydrocarbon oil at a temperature in the range between 100 and 200 F. to form an oil phase, an intermediate phase and an aqueous phase, separating and recovering said oil phase and said aqueous phase, removing pro pane from said oil phase and recovering an oil substantially free of salt of said organic acid.

5. A process for producing a hydrocarbon substantially free of salts of organic acid which comprises forming a mixture of a hydrocarbon oil selected from the group consisting of neutralized slop oils, neutralized sludges resulting from treat ment of lubricating oil fractions in propane solution with sulfuric acid, neutralized bottoms fractions from the distillation of naphtha, oil resulting from the distillation of crude petroleum and its fractions over caustic, and neutralized acid oils resulting from treatment of lubricating oil with sulfuric acid containing sodium naphthenate and about 25% by volume of water, agitating vigorously said water-containing admixture to emulsify same, extracting the emulsified admixture with liquefied propane in an amount in the range from 2 volumes to about 10 volumes per volume of hydrocarbon oil at a temperature in the range between 100 and 200 F. to form an oil phase, an intermediate phase and an aqueous phase, separating and recovering said oil phase and said aqueous phase, removing propane from said oil phase and recovering a substantially sodium naphthenate-free oil.

6. A process for producing a hydrocarbon substantially free of salts of organic acid which cornprises forming a mixture of a hydrocarbon oil selected from the group consisting of neutralized slop oils, neutralized sludges resulting from treatment of lubricating oil fractions in propane solution with sulfuric acid, neutralized bottoms frac tions from the distillation of naphtha, oil resulting from the distillation of crude petroleum and its fractions over caustic, and neutralized acid oils resulting from treatment of lubricating oil with sulfuric acid containing sodium sulfonate and about 25% by volume of water, agitating vigorously said water-containing admixture to emulsify same, extracting the emulsified admixture with liquefied propane in an amount in the range from about 2 volumes to about volumes per volume of hydrocarbon oil at a temperature in the range between 100 and 200 F. to form an oil phase, an intermediate phase and an aqueous phase, separating and recovering said oil phase and said aqueous phase, removing propane from said oil phase and recovering a substantially sodium sulfonate-free oil.

7. A process for producing a hydrocarbon substantially free of salt of an organic acid hydrocarbon which comprises forrning a mixture of a hydrocarbon oil selected from the group consisting of neutralized stop oils, neutralized sludges resulting from treatment of lubricating oil fractions in propane solution with sulfuric acid, neutralized bottoms fractions from the distillation of naphtha, oil resulting from the distillation of crude petroleum and its fractions over caustic, and neutralized acid oils resulting from treatment of lubricating oil with sulfuric acid containing an alkali metal salt of an organic acid selected from the group consisting of naphthenic and sulfonic acids and about 25% by volume of Water, agitating vigorously said Water-containing admixture to emulsify same, extracting the emulsified admixture with liquefied propane in an amount in the range from about 2 volumes to about 10 volumes per volume of hydrocarbon oil at a temperature in the range between 100 and 200 F. to form an oil phase, an intermediate phase and an aqueous phase, separating and recovering said oil phase and said aqueous phase, removing propane from said oil phase and recovering an oil substantially free of salt of said organic acid.

8. A process for producing a hydrocarbon substantially free of salts of an organic acid which comprises forming a mixture of a hydrocarbon oil selected from the group consisting of neutralized slop oils, neutralized sludges resulting from treatment of lubricating oil fractions in propane solution with sulfuric acid, neutralized bottoms fractions from the distillation of naphtha, oil resulting from the distillation of crude petroleum and its fractions over caustic, and neutralized acid oils resulting from treatment of lubricating oil with sulfuric acid containing sodium naphthenate and sodium sulfonate and about 25% by volume of water, agitating vigorously said water-containing admixture to einulsify same, extracting the emulsified admixture with 4 volumes of liquefied propane per volume of hydrocarbon oil at a temperature about F. to form an oil phase, an intermediate phase and an aqueous phase, separating and recovering said oil phase and said aqueous phase, removing propane from said oil phase and recovering an oil substantially free of sodium naphthenate and sodium sulfonate.

9. A process for producing a hydrocarbon oil substantially free of salts of an organic acid which comprises forming an admixture of an oil selected from the group consisting of neutralized slop oils, neutralized sludges resulting from treatment of lubricating oil fractions in propane solution with sulfuric acid, neutralized bottoms fractions from the distillation of naphtha, oil resulting from the distillation of crude petroleum and its fractions over caustic, and neutralized acid oils resulting from treatment of lubricating oil with sulfuric acid containing an alkali metal salt of an organic acid selected from the group consisting of naphthenic and sulfonic acids and about 25% by volume of water, agitating vigorously said water-containing admixture to emulsify same, extracting the emulsified admixture with about 4 volumes of propane per volume of hydrocarbon oil at a temperature of about 150 F. to form an oil-propane admixture, washing the oil-propane admixture with further quantities of water, settling the Washed oil-propane admixture to form an oil phase, an intermediate phase, and an aqueous phase, separating and recovering said oil phase and said aqueous phase, removing propane from said oil phase, and recovering an oil substantially free of salts of said organic acids.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,235,639 Koch Mar. 18, 1941 2,301,335 Showalter et al. Nov. 10, 1942 2,406,748 Dickinson Sept. 3, 1946 2,413,310 Bloch Dec. 31, 1946 2,446,040 Blair July 27, 1948

Claims

9. A PROCESS FOR PRODUCING A HYDROCARBON OIL SUBSTANTIALLY FREE OF SALTS OF AN ORGANIC ACID WHICH COMPRISES FORMING AN ADMIXTURE OF AN OIL SELECTED FROM THE GROUP CONSISTING OF NEUTRALIZED SLOP SOILS, NEUTALIZED SLUDGES RESULTING FROM TREATMENT OF LUBRICATING OIL FRACTIONS IN PROPANE SOLUTION WITH SULFURIC ACID, NEUTRALIZED BOTTOMS FRACTIONS FROM THE DISTILLATION OF NAPHTHA, OIL RESULTING FROM THE DISTILLATION OF CRUDE PETROLEUM AND ITS FRACTIONS OVER CAUSTIC, AND NEUTRALIZED ACID OILS RESULTING FROM TREATMENT OF LUBRICATING OIL WITH SULFURIC ACID CONTAINING AN ALKALI METAL SALT OF AN ORGANIC ACID SELECTED FROM THE GROUP CONSISTING OF NAPHTHENIC AND SULFONIC ACIDS AND ABOUT 25% BY VOLUME OF WATER, AGITATING VIGOROUSLY SAID WATER-CONTAINING ADMIXTURE TO EMULSIFY SAME, EXTRACTING THE EMULSIFIED ADMIXTURE WITH ABOUT 4 VOLUMES OF PROPANE PER VOLUME OF HYDROCARBON OIL AT A TEMPERATURE OF ABOUT 150* F. TO FORM AN OIL-PROPANE ADMIXTURE, WASHING THE OIL-PROPANE ADMIXTURE WITH FURTHER QUANTITIES OF WATER, SETTLING THE WASHED OIL-PROPANE ADMIXTURE TO FORM AN OIL PHASE, AN INTERMEDIATE PHASE, AND AN AQUEOUS PHASE, SEPARATING AND RECOVERING SAID OIL PHASE AND SAID AQUEOUS PHASE, REMOVING PROPANE FROM SAID OIL PHASE, AND RECOVERING AN OIL SUBSTANTIALLY FREE OF SALTS OF SAID ORGANIC ACIDS.