US1811243A - Process of refining hydrocarbon oils with metallic halide - Google Patents

Description

June 23, 1931. J. H. OSMER 1,811,243

PROCESS OF REFINING HYDROCARBON OILS WITH METALLIC HALIDE fined Feb. 25, 1927 IDEPHLE COHIIIISIR 5 wscnwnr gas and coke.

Fatentecl June 23, 1931 UNITED STATES PATENT OFFICE JAMES HAROLD OSME'R, OF EL SEGUNDO, CALIFORNIA, ASSIGNOR T0 STANDARD OIL COMPANY OF CALIFORNIA, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF DELAWARE PROCESS OF REFINING HYDROGARBON OILS WITH METALLIC HALIDE Application filed February 25, 1927. Serial No. 171,045.

This invention relates to the art of improving oils, and it comprises contacting, continuously or intermittently, a blend of a light and a heavy oil with a metallic halide at a temperature insuflicient to convert any substantial part of this blend to lower boiling oils, together with the subsequent separation, by distillation, of the light and heavy components of the blend; all as more fully hereinafter set forth,

It is a well known fact that various metallic halides, of which the preferred example is anhydrous aluminum chloride, are capable of various reactions with hydrocarbons, such as those which compose petroleum oil, and of modifying their character in many ways. (in heating a relatively high boiling petroleum oil, such as a gas oil, a lubricating oil I distillate, or 'a fuel oil, with aluminum chloride, the latter under proper conditions will convert the whole ofsuch high boiling oil into lower boiling oils of the nature of gasoline, with the exception of a varying loss as It is noteworthy that the products of such a distillation will consist almost entirely of so-called saturated hydrocarbons, and that the sulfur content as well as the nitrogen and oxygen content of such distillate will be extremely low. This is true even though the original oil was highly unsaturated and contained high percentages of the various impurities comm-only found in petroleum oils which consist mainly of the compounds of sulfur, oxygen and nitrogen with hydrocarbons. Such a conversion of high boiling to low boiling oils on a commercial scale usually requires a temperature not less than 400 F. It is customary to use temperature well above 400 F., and it is often desirable touse pressures above atmospheric in order to bring about a quantitatively sufficient conversion or cracking.

By operating at a sufliciently low temperature the above described converting action may be avoided, while at the same time the saturating and purifying action may be retained. In addition there frequently results in greater or less degree a chemical rearrangement similar to polymerization. Thus in the case of a light oil, such as naphtha, one

ride.

When heavy oils are treatedat comparatively low temperatures with aluminum chloride or the like, one very serious difficulty lies in the separation of the catalyst and the products of the reaction from the purified oil. lhese products consist mainly of very viscous, tarry, dark-colored fluids. The oil treated is itself, at these low temperatures, comparatively viscous. In order to make the treatment at all efficient it is necessary to bring about intimate contact between the catalyst and the oil, and this involves violent agitation in one form or another. As a result, the catalyst and the products of the reaction are finely subdivided and mingled throughout the oil body. Due to the high viscosity of the two fluids and the small difference in their specific gravities, it is impossible to make an adequate separation by gravity settlement. Centrifuging may be resorted to but is costly and difiicult. Water washing is not advisable becauseof the action of the waterupon the aluminum chlo- One of the results of such action is the formation of aluminum hydroxide which is precipitated as a gelatinous substance and which, in .the presence of lubricating oil stock, has a strong tendency to emulsify. The emulsions formed in this manner are extremely stable. Various methods may be employed for breaking such emulsions, but these are costly and have a tendency to reduce the yield of finished lubricating oil stock. Redistillation is not advisable at this stage because of the fact that one of the results of the action of aluminum chloride upon oil is the formation of varying amounts of v out the use of steam in the distillation. There fore this expedient could not be employed at this stage. Nor would it be practical to first neutralize the oil by washing with an alkali solution, since there is a strong tendency toward the formation of semi-permanent emulsions with an oil containing tracesof aluminum chloride.

Another disadvantage inthe use of aluminum chloride for thetreatment of lubricating oil stock lies in the fact that some mechanical stirring device must be used to keep the aluminum chloride in suspension in the oil body. Such a device, however perfect mechanically, represents an added cost an an added operating diificulty.

All attempts to treat lubricating oil with metallic halides continuously have been of doubtful practical value, because of the many mechanical or operating details encountered.

The treatment of lighter oils such as motor gasoline and burning oils, with aluminum chloride and the like produces results of the same general nature as those obtained in the case of lubricating oils. That is to say, sat

uration, sulfur removal, etc., are realized. In this case, the separation of the reagent and the reaction products from the treated oil takes place much more readily by simple gravity settlement. The difference between the specific gravities of the two'substances accounts in some measure for this fact. The low viscosity of the oil is a further aid to rapid separation. I

In the present invention, the difficulties which. have been enumerated above are overcome and various other advantages are realized.

Brieflythis process consists in first blending two oils which itis desired to refine. One of the components is a comparatively heavy, high-boiling oil such as a lubricating oil stock. The other is a comparatively light, low boiling oil such as gasoline. The composite or blended .oil is warmed to about 200 F. and then contacted with a metallic halide such as anhydrous aluminum chloride. Following thecontacting the halide and reaction products are largely removed by gravity settlement. Owing to the low viscosity and low specific gravity of the oil this settlement takes place rapidly and very nearly completely. The two purified oils are then separated by distillation, or better, the.

blend is first contacted with a small quantity of Sulfuric acid to remove the last traces of the halide, the oil is then washed free of acid,

able in the case of heavy oils.

distillation. This process is admirably adapted to use in continuous treatment, an

advantage otherwise commercially unattain- It insures rapid removal of spent treating reagent and sludge, easy contact of oil and treating reagent, and other advantages to be explained below.

In order that the invention may be'better understood in its various aspects there is described below a detailed example of the working of a process comprising a preferred embodiment of my invention. In connection with this description reference may be made to'the accompanying drawings which illustrate an apparatus in which the process may be performed. The indicated apparatus is given for illustrative purposes only, and it is to be understood that the arrangement shown, and the details of construction illustrated,

may be widely varied without departing from the .scope of my invention.

In this example, which isltypical of the op-.

eration of the process, the oils to be refined are a lubricating oil distillate from California crude, and a motor gasoline from the same crude. The gravity of the former-is about 20 A. P. I. while that of the-latter is. about 53 A. P. I. The two are mixed, as by pumping through aline together, in the proportions of approximately 20% of the heavy oil to 80% of the light oil. The process is to be, in this case, a continuous one, and'the apparatus is therefore gas tight and capable of .withstanding pressures up to 50 lbs. gauge.

In the drawing, 4; represents a line through which theblended oil comes to the system. The admixture of heavy oil and lighter oil is continuously passed through a suitable means for heating the same, such as the heater 5, indicated as in the form of a steam heater operating through the use of exhaust steam introduced through line 6 and withdrawn from the heater through line 7. Within the heater- 5, the hydrocarbon oil is preferably raised to a temperature of about 200 F. At the same time apart of the hydrocarbon oil is withdrawn through line 8 controlled by a valve 9a and introduced into a mixer 9 wherein it is admixed with the aluminum chloride or other metallic halide for the process, said aluminum chloride being introduced through hopper 10 and line 11. The quantity of metallic halide introduced will depend uponthe character-of hydrocarbon oil processed but generally from .1 to 1 pound of metallic halide is employed per gallon of oil treated.

.Only suflicient'oil is by-passed through the line 8 to make a fluid mixture with the halide so that it'may be more easily introduced the main line. This fluid mixture is co" nuously passed from the mixer 9 throughfline' 1 2 in to the main oil stream which latter flows from the heater 5 through line 13. The warm oil and halide are then itated together in a suitable manner so that t e metallic halide isthoroughly contacted with the oil. For example, the admixture ma be made to flow through a long pipe in w 'ch are numerous right-angle bends 15. The turbulent flow through this line insures thorough commingling. Various other methods of making contact are known and are at the disposal of the operator to-fit particular needs. In any case the temperature, contacttime and'amount of halide will be so'regulated as to accomplish the desired amount of purification-of the oil, that is, of the blend of light'and heavy oil.

From the conduit 14, the admixture is passed throu h line 16 into a settling or stratresidue is continuousl withdrawn through ously withdrawn from the top about pound or less of 66 line 18. The hydrocar on oil is also continuof the stratifying chamber 17 throu h line- 19. Within the stratifying chamber 1 the admixture is still above 150 F., and a certain amount of additional reaction may take place therein.

The hydrocarbon oil which overflows from the stratifying chamber 17 is substantially free from aluminum chloride and reaction products. Traces, however, remain and to remove such traces, sulfuric acid is added to the hydrocarbon oil in line 19 from line 20. In line 19, the acid and oilcommingle sufliciently for the sulfuric acid to remove all traces of aluminum chloride. Generally Baum acid per gallon of oil is suflicient for this treatment.

- The admixed oil and acid as through line 19 into an acid strati g c amber 22 wherein the acid settles an is Withdrawn through line 21. The oil .is withdrawn from the chamber and passed through line 23 into a washer 24 wherein it is continuously sprayed with water from a line 25. The wash water is continuously withdrawn through; the line 26 at the bottom of vessel 24 and the oil continuously discharged through line 27 at the top and passed into a caustic soda treater or neutralizer 28. In theneutralizer 28, caustic soda or other alkali is continuously sprayed into I the oil from a line 29, the caustic soda bein removed through the line 30 at the bottom of the vessel. The oil is withdrawn through the line 31 at the top of the vessel and passed through a second washer 32. In the second washer 32, the oil is sprayed with wash water from a line 33, which wash water is withdrawn from the bottom of the vessel through line 34. The oil is'withdrawn from the top of the washer 32 through the line 35.

- From the line 35, the oil is next passed by pump 36 to a still 37 wherein the oil is continuously or intermittently distilled to .remove the light stock. This distillation is preferably assisted by steam from a line 38. The vapors from still 37 may be fractionated in a fractionating tower 39 and the gasoline produced then condensed in the coil 40 and collected in the tank 41. The oil remaining in still 37 after the light oil has been removed may be processed in any. way desired. For example, it may be subjected toa reducing distillation or chemically treated orboth or neither.

It has been found that after the first passage of the light stock through the process the action of the aluminum chloride or other metallic halide, on the light stock 1s substantially complete and hence all of the valuable strength of the aluminum chloride used may therefore be expended in refining or purifying the heavy oil. In other words, if the refiner does not care to purify light oil by this method, -he may reuse indefinitely a quantlty of light oil without extra expenditure of the halide reage'ntsThe light oilwhich is recycled is then merel a diluent and carrier for the heavy oil. A ter separation from the blend (as in still 37) it maybe returned for.

reblendin through line 42 and 2 to a mixing chamber 3. This chamber is suitably battled so as to insure thorough mlxmg of the two oils, the heavier of which enters through line 1. Should the process be operated in this way it'will be unnecessary, and even undesirable, to completely cool and condense the'oil in coil 40, since this oil may be used to heat the incoming heavy oil and give a blend with a temperature of 200 F., or

thereabouts. Furthermore, if the diluentoil is recycled in this manner it will be of advantage to increase as far as poss ble the percentage of heavy oil in the blend, and to use, as diluent, a comparatively low bollmg point, narrow range gasoline so as to reduce the heat and time required for separation, etc.

There are certain other variations of the process which are possible Without'departing from the essential features of the invention. An example liesin the distillation which follows the treating. Primarily its object is the separation of the two components of the' blend, but it may do. more than-this, It may be used as a purifying and sweetening redistillation (particularly in regard to the heavy g oil). It may be made a reducing distillation for lubricatin oil. .It may serve to produce any desired. oiling-point range gasoline. Thus naphtha may have been used as the diluent and the distillation may be so regulated as to give motor gasoline, illuminating oil stock and lubricating oil stock." In general distillates which have been imperfectly:- or' slightly fractionated may be used in the blend furnished to the process, and the final distillation may be used to effect complete or close fractionation. In some cases advantage til may accrue from the use of pressures below or even above atmospheric on the distillation process. Any one skilled in the art of refining oils will be able to determine this point in any given circumstance.

In the foregoing description of the operationi of this inventionfit has been,assumed that the temperatures prevailing during the aluminum chloride treatment will be in the neighborhood of 200 F. This, however, is not an essential condition. The temperature used may be atmospheric or below or it may be well above 20Q 'F., depending upon the nature of the oils undergoing treatment and the quality of products desired. The tem perature may be raised to such a point that conversion of high boiling to low boiling oils takes place in some degree. In this event, the yield of light oil will be increased at the expense of the heavy oil, or an intermediate oil may be obtained by moderate conversion. In the preferred form of the apparatus, the treatment is carried out continuously in a vapor-tight apparatus. Therefore, the temperature employed in any case will not result in light vapor losses. The use of a heavy oil along with the light oil serves to reduce the vapor pressure of the mixture at any given temperature below the pressure which would normally be developed by the same light oil'under the same conditions.

.This process need not be carried out continuously. In certain cases, it may be desirable to operate intermittently, i. e., by a batch method.

In the example given above it has been stated that the aluminum chloride was introduced by mixing with a quantity of oil. However, this introduction may be carried out in other ways, as by feeding pulverized aluminum chloride directly into the oil to be treated, etc.

Instead of using gasoline as a cutter stock or diluent in this process, various other oils may be used. For example, illuminating oil distillate ordinarily known as water-white distillate may be used-with the same advantages mentioned in the case of gasoline. No limitation to the nature of the oils used is intended in this description of my invention except that from its nature itwill be neces-' sary touse oils which difier markedly in viscosity and boiling points. Neither is my invention limited to the use of anhydrous aluminum chloride as a treating reagent or catalyst. Various other --metallic halides, such as ferric chloride, zinc chloride, etc., may be used to advantage. I

, The process as it has been described above may or may not produce cbmpletely finished oils. It may be desirable to precede or folexample, the oil may be filtered through fullers earth, decolorizing clay or the like, or it may befiltered through canvas bags or similar devices. The dilution of the heavy oil makes possible a number of processes of this kind which would otherwise be impossible or at best impracticable. In some cases settlement alone or direct neutralization will serve to prepare the oil for distillation.

The mixing of a light oil with a heavy oil which is to be treated by the metallic halide is found to afford certain advantages not heretofore obtained in the treatment or refinement of heavy oil stocks by metallic halides. .In the firsttplace, the light oil acts as a carrier for the heavy lubricating distillates which, instead'lof being viscous and diflicult to handle, are made fluid so that the metallic halide may readily contact with all parts of the heavy oil and may be easily separated by gravity or filtration therefrom. Moreover, the use of a diluent permits the ready removal of the residual traces of aluminum chloride by acid, water and alkali treatments, in which these treating reagents are merely pumped or sprayed into the hydrocarbon oil. Furthermore, the refining of the heavy lubricatin oil stock by the metallic halide may be e ected without the necessity of employing mechanical stirring devices.

This process likewise operates to conserve oil or increase the treating yield. Any of the polymerized hydrocarbons resulting from the low" temperature treatment of the gasoline or light oilby the metallic halide will be absorbed and incorporated intothe heavy components of the mixture and the result will be a saving of reaction products of this type. Conversely if the process proceeds with any conversion of high boiling point oils to low boiling point oils resulting from a metallic halide cracking reaction, these low boiling point oils will be automatically absorbed by and incorporated in the-cutter stock of the mixture.

I claim 1. A process of refining a heavy hydrocarbon oil which comprises forming a mixture of'said heavy oil and a lighter oil previously treated with a metallic halide, contacting said mixture with a metallic halide at a temperature insuflicient to cause any substantial conversion. to'lower boiling oils,

and separating purified heavy oils from the light oil.

2. In a process of refining a heavy high boiling oil, the steps of forming a mixture of heavy high boiling oil to be purified with a purified light low boiling oil, and contacting such mixture with a metallic halide at a temperature above atmospheric but below that at which any appreciable conversion of the heavy oil into lower boiling oil takes place.

3. In a process of refining a heavy high boiling oil, the steps of forming a mixture of heavy high boiling oil to be purified with a purified light low boiling oil, contacting such mixture with a metallic halide at a temperature above atmospheric but below that at which any appreciable conversion of the heavy oil into lower boiling oil takes place, removing metallic halide and reaction products from the mixture, and separating the purified heavy oil from the light low boiling oil.

4. In a process of refining a heavy high boiling oil, the steps of forming a mixture of heavy high boiling oil to be purified with a previously purified light low boiling oil, contacting such mixture with a metallic halide at a. temperature of about 200250 F. and insulficient to cause any substantial conversion of the heavy oil into lower boiling oil, removing metallic halide and reaction products from the mixture, and separating the purified heavy oil from the light low boiling oil.

a). In a process of refining heavy high boiling oils of the character of lubricating stocks,

the steps of forming a mixture of heavy high boiling oil of the character of lubricating stock to be purified with a previously purified light low boiling oil, .and contacting such mixture with a metallic halide at a temperature above atmospheric but below that at which any appreciable conversion of the heavy oil into lower boiling oil takes place.

6. In a process of refining heavy high boilin g oils of the character of lubricating stocks, the steps of forming a mixture of heavy high boiling oil of the character of lubricating stock to be purified with a previously purified light low boiling oil, contact-ing such mixture with a metallic halide'at a temperature above atmospheric but below that at which any appreciable conversion of the heavy oil into lower boiling oil takes place, removing metallic halide and reaction products from the mixture, and separating the p irified heavy oil from the light low boiling o1 Signed at San Francisco, California, this 27th day of- January, 1927.

JAMES HAROLD OSMER.

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