US2019037A - Manufacture of improved hydrocarbon products - Google Patents

Description

Oct. 29, 1935.

MANUFACTURE OF IMPROVED HYDROCARBON ,PRODUGTS E. 'AYRES ET AL Filed March. 10, 1932 CIRCULATJNG 5R8 PUMP AGITATOR 51. up 615 @zcsl vER FIRE AND STEAM STILL FILTER PRESS FOR RES/DUE E ene 07 ms Hamel GSZvith,

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Patented Oct 29, 1935 UNITED STATES PATENT OFFICE MANUFACTURE OF IMPROVED HYDRO- CARBON PRODUCTS Application March 10, 1932, Serial No. 598,096 6 Claims. (01. 196-78) This invention relates to manufacture of lubricating oils; and it comprises a process of produc ing finished high quality lubricating oils from mixtures of technical petroleum stocks ranging in type from tar residues to light distillates, wherein a relatively high boiling petroleum stock is mixed with a lower boiling stock, the mixture is heated to a temperature not above 300 F. in the presence of anhydrous aluminum chlorid and added HCl to produce a synthetic stock of characteristics intermediate those of the two original stocks and in yield much greater than is obtainable by a similar treatment applied to the original stocks separately, the synthetic stock which contains some aluminum chlorid sludge is settled for removal of the bulk of sludge, is decanted, traces of aluminum chlorid sludge remaining in suspension in the decanted liquid are decomposed and the products of decomposition are substantially completely removed, to pro duce a finished lubricating oil substantially free from impurities; all as more fully hereinafter set forth and as claimed.

Several different, specific eifects of anhydrous aluminum chloride on petroleum stocks have been described in the literature. A few of these effects now form the basis of commercial processes. For example, it is known that aluminum chlorid has the effect of causing the condensation or polymerization of hydrocarbons at relatively moderate temperatures.- Bythis means, synthetic lubricating oils of naphthenic'type have been made from volatile olefines. The refining of lubricating oil stocks by warming with aluminum chloride is also known. Such processing involves the removal in the form of a heavy sludge of certain undesirable constituents of the stock, possibly by the condensation of the constituents least saturated with respect tomhydrggen to form high molecular weight compounds insoluble in oil. It is characteristic of such processes that the oil is changed in character; they break down the molecular structure of the oil and produce the formation of substantial proportions ofoils of lower viscosity than that of the starting material. The reason .for this breaking down effect is that the aluminum chloride of itself is not ordinarily an effective refining agent unless the temperature of the oil is above normal. In any event a considerable amount of the starting stock is lost to the sludge and the yield of refined oil is low.

A third example of the known eifects of aluminum chloride is the use of this material to promote the breaking down of heavier oils to form motor fuel and kerosene. At temperatures above 300 F. the analytic or converting effect of aluminum chloride predominates, and at temperatures below-300 F. the synthetic effect of aluminum chloride, although dominating the analytic e1.-v

fect, may cause the formation of oil insoluble bodies in large amounts.

In the present invention in its aspect of producing a synthetic lubricating oil stock in high yield, aluminum chlorid in the presence of added HCl is used for synthesizing lubricating oils from mixtures of hydrocarbon stocks. In the principal embodiment of the invention, a relatively thick,

viscous and high boiling oil stock is admixed with a lighter stock. In the course of treatment, some 10 sort of combination of the stocks takes place. There is, to a certain extent, what may be called an averaging of the two oils; and the new oil produced therefrom may be termed a synthetic product. That this synthesizing effect occurs is evidenced by the fact that the yield of oil obtained in the process is much greater than the sum of the yields obtained by carrying out a similar process upon the two components separately and mixing the products. I

The HCl as used in our process appears to have a transitory function. The entire chlorine content of the gas appears at the end of the reaction as hydrogen chloride. No chlorinated hydrocarbons appear in the product. The hydrogen chloride can be readily recovered at the end of the reaction and can then be reintroduced or recycled. t I

Our synthesizing process is carried out upon mixtures of hydrocarbons of different characteristics. In the principal embodiment of the invention, the two hydrocarbon components are a high boiling petroleum stock anda lower boiling stock. To the extent that the two stocks combine molecularly, the yield of high grade products is higher than the yield obtainable froma treatment of the charging stocks separately. When one of the hydrocarbon components is of low molecular weight, its presence has an .additional effect: a thinning action; ensuring, by dilution of viscous oils, better contact with the aluminum chlorid.

In general, our process is accomplished by contacting dry hydrogen chloride, for example, with the hydrocarbon stock to be treated, adding a suitable proportion of anhydrous aluminum chloride, agitating at a suitable temperature for a suitable period of time, separating the sludge from the residual'oil, neutralizing the separated oil and finishing in such manner as to obtain the desired appearance or purity of product.

The contacting of the oil with dry gaseous hydrogen chloride in our process can be accomplished conveniently at ordinary temperatures and pressures, but elevated pressures may be advantageous particularly when elevated temperatures are employed. Pressures up to pounds per square inch have been used in some cases. The oil may be merely held in contact with an atmosphere of the hydrogen chloride, 6

with or without agitation, or the latter may be blown-through a body of the oil. When atmospheric pressure is used it is advantageous to maintain the contact with hydrogen chloride for an hour or more. At slightly elevated temperatures and under super-atmospheric pressures the same degree of preparation of the hydrocarbon stock may be accomplished within 5 to 10 minutes. It is advantageous, although not necessary to maintain contact with excess hydrogen chloride during the subsequent treatment with aluminum chloride. Aluminum chloride in its reaction with hydrocarbons generates some hydrogen chloride but we have found that the small amount of hydrogen chloride so generated is not capable of giving the results obtainable by thisinvention.

An excess over this amount is necessary. It has also been found that the aluminum chloride used in our process cannot be replaced by metallic aluminum used with C12 or HG]. If there is a reaction between such aluminum and the dry hydrogen chloride or chlorine used in our process, this reaction is, at all events, not sufflciently rapid. The results are not the same.

Instead of contacting the hydrocarbon stock with hydrogen chloride prior to treatment with aluminum chloride, satisfactory results may be secured by contacting with hydrogen chloride only during the treatment with aluminum chloride, provided this treatment is conducted at moderate temperatures.

We have found it practical in some instances to substitute gaseous chlorin for the 1101 gas used in our process prior to or during treatment of stock with aluminum chloride. So doing, the net result appears to be the same; the chlorine is quantitatively removed at the end of the reaction as I-ICl.

' Operation is under conditions such that no substantial chlorination of the hydrocarbons present takes place.

The proportion of anhydrous aluminum chloride used in our process may be varied within wide limits. We advantageously use between 1 and 10 per cent by weight of the hydrocarbon stock. In the processes illustrated subsequently 1 per cent of aluminum chloride was found sufficient to give a 94 per cent yield of a slightly improved lubricating oil with a viscosity at 210 F. of 86 seconds compared with 75 for the starting material, which in this case was a lubricating stock from a Coastal crude. But with the use 01' 10 per cent aluminum chloride and the same lubricating stock, the viscosity at 210 F. of the finished product was raised to 107 seconds and the quality approached that of Pennsylvania oil, with an 8'7 per cent yield. Larger proportions of aluminum chloride are usually attended by larger losses. The efiects on the reduction of carbon residue are more marked at higher temperatures with larger proportions of aluminum chloride, but at lower temperatures relatively little aluminum chloride is required. With 3 per cent aluminum chloride at room temperature the carbon residue of a mid-continent bright stock with a viscosity at 210 F. of 150 seconds can be reduced from 1.75 to 0.55, for example.

By the use of an excess of hydrogen chloride muchless aluminum chloride is required than in the ordinary known process. The temperatures suitable for our processes vary between those considerably below room temperature and those somewhat above 212 F. Temperatures above 300 F. are not satisfactory because at elevated temperatures the action of aluminum chloride is to break down the hydrocarbons to form light gen carbon ratio hydrocarbon stocks, the maximum effect on the viscosity-temperature relationship appears to be at low temperatures, whereas with relatively high hydrogen carbon ratio hydrocarbon stocks, higher temperatures produce better results.

The time of agitation of the hydrocarbon stock with aluminum chloride should be long enough to insure a complete reaction. At low temperatures it is obviously advantageous to use a longer time than at high temperatures. In general a period of one hour gives satisfactory results.

The dilution of the hydrocarbon stock with low molecular weight hydrocarbons is advantageous in the case of the treatment of hydrocarbons of higher molecular weight and particularly of viscous oils. For example, in the treatment of pressure-still tar alone there is obtained a 33 per cent yield of good quality oil with a viscosity of 42 seconds at 210 F., whereas in the presence of an equal part of a cracked gasoline a 9'7 per cent yield may be obtained of oil of the same quality and viscosity. On the other hand after a treatment of the cracked gasoline sepa-- rately, conditions of treatment being otherwise the same, no measurable yield of lubricating oil was secured. The treatment of a mid-continent bright stock alone gives a 60 per cent yield of oil of Pennsylvania quality with viscosity of seconds at 210 F., but in the presence of 20 per cent uncracked mid-continent gasoline we obtain a 65 per cent yield of oil of Pennsylvania quality with viscosity of 143 seconds (S. U. V.).

The chemical characteristics of the diluent have a marked cifect on the results, but all types are useful. Pure olefines such as amylenes may be used to advantage. Cracked gasolines containing ring compounds as well as olefines and uncracked gasolines' containing principally paraflins and naphthenes, or even pure benzene or toluene, or any combinations of these hydrocarbons, may be used. The increase in yield is somewhat more marked with diluents of the olefine type. This is not because of a polymerization or condensation of the olefins to form an oil, by the action of aluminum chloride, because a treatment of the olefine alone under the prescribed conditions gives no measurable yield of lubricating oil.

In the case of the treatment of certain types of stocks by our process, particularly those types that contain unsaturated lubricating fractions or naphthene lubricating fractions, we often secure lubricating ,oils that are mixtures of oils of improved quality with some fractions of inferior quality. The formation of refined lubricating oil fractions of poorer quality appears to be the result of side reactions, with polymerization or condensation of heavy hydrocarbons to products having the undesirable characteristics of low gravities, poor viscosity-temperature curves, and comparatively high carbon residue tests. These side reactions or by-products occasionally encountered are evidently largely due to the-presence of substances in thecharging stocks of the nature of hydrocarbons of the di-olefine, acetylenic or aromatic types. When such reaction products are encountered in suflicient amount to affect the quality of the finished lubricating oilmixture to an undesirable extent, we can often effect some improvement in quality by distilling from the final treated oil, fractions of improved quality, as the undesirable products are often of much higher boiling range than the other fractions and therefore .can be concentrated in a heavy residual oil from a fire and steam reduction at either atmospheric pressure or under vacuum.

The intermediate stock obtained by the treatment described of a mixture of charging stocks with the aid of aluminum chlorid and added HCl, is not a finished lubricating oil and cannot be used directly as such. It is necessary to apply a finishing treatment to get out all traces of aluminum chlorid, or aluminum chlorid sludge, remaining in the synthesized stock. The stocks do not yield readily to treatment by common methods for finishing oils in general and we have developed methods particularly suitable for finishing such stocks. Three finishing methods which we have found most suitable, for producing a finished oil from syntheticstocks are the following:

1. To the sour oil decanted from the aluminum chloride sludge is added some fine clay and hydrated lime; the. oil thereafter being filtered. Heating of the oil-lime-clay mixture before filtering is usually advantageous. Two-tenths of a pound of lime per barrel of oil per acid number is about suficient for neutralization, but it is desirable to use an excess such as 0.6 pound per barrel per acid number. Suflicient clay should be used to facilitate filtration. This usually requires from 0.4 to 0.8 pound of clay per gallon of oil, when natural Florida or Georgia clay is employed.

2. The sour oil decanted from the aluminum chloride sludge is agitatedwith dilute sulfuric acid to decompose suspended aluminum chloride sludge or compounds. After settling out the dilute acid wash, the oil may be treated, if desired, with a small amount of strong sulfuric acid, or contacted with fine clay, or filtered through coarse burned'clay. The dilute acid may be as weak as 5 per cent or less, or may be stronger than 20 per cent unless, in a particular case, the strong acid causes a stable suspension in the oil of acid sludge particles or decomposition products therefrom.

3. The sour oil decanted from the aluminum chloride sludge is heated to a temperature at which thetracesof suspended aluminum chloride sludge .will completely react with the oil. This temperature is usually between 450 F. and 550 F. After the sludge is spent, the oil can be satisfactorily filtered.

Our invention is illustrated in the accompanying drawing which shows, in the form of flow sheets (Figs. 1 and2) two typical processes within the purview of our invention, wherein a lubricating oil stock is mixed with a lighter hydrocarbon and the mixture is treated by a. series of successive operations with the ultimate production of a finished lubricating oil of improved properties. The several successive operations are indicated on the flow sheets by appropriate legends.

Referring to the flow sheet of Fig. 1, a lubricating oil stock is shown introduced into an agitator together with a light fraction. Aluminum chloride is introduced and hydrogen chloride is circulated through the agitator. Sludge is drawn ofi after completion of the reaction and the refrom the still while the bottoms are passed through a filter press for removal of clay and lime residues, a finished lubricating oil being finally recovered.

Fig. 2 shows a modification of the invention, the finishing steps being different. The treatment with aluminum chloride and HCl is the same as in Fig. 1. The sour oil obtained at the end of this treatment is settled and is then mixed with a suitable quantity of dilute sulfuric acid with agitation. The oil is then permitted to settle out impurities, and is contacted with fine clay or illtered through coarse burned clay. A finished lubricating oil of high quality is recovered by this treatment.

Our invention is further illustrated by the following illustrative examples which represent practical embodiments thereof.

1. Treatment of 'mid-continent bright stock One hundred volumes of a bright stock from Oklahoma crude petroleum were contacted with dry hydrogen chloride at ordinary temperature and pressure for four hours. While continuing the contact of hydrogen chloride, the oil was then warmed to 275 F. and stirred for about 2 hours with 10 per cent by weight of anhydrous aluminum chloride. The sludge was permitted to settle and the decanted sour oil was steamed at 450 F. with 0.5 pound fine clay per gallon and 0.6 pound hydrated lime per acid number per barrel. The residue was filtered through-paper. The yield of finished oil was found tobe 60 volumes. The following table shows comparative tests made on the charging stock and on the final products.

Charging stock Product Gravity: A. P. I 22.8 29,9 Viscosity, S. U. V.:

100 F 3,007 846 56 105 420 505 +25 Color, N. P. A 4. 75 l. 75 Carbon residue: Per cent 1.42 0.04

The above tests show a greater effect on the viscosity index than is normally secured.

2. Treatment of mid-continent bright stock example. The yield of finished oil was 149 vol- .umes. Comparative tests on this oil yielded the followm g results:

x 1 Product 7 Gravity: A. P. I 23.0 24. Viscosity, S. U. V. 3

210 151 119 Viscosity, index (Dean and Davis 73 78 Flash, 0. 0.: F. 545 495 Fire, 0. 0.: F 630 570 Pour: F +15 +15 Color, N. P. A 7.5 7. 5 Carbon residue: Per cent- 1.75 0. 55

This example illustrates a remarkably high yield of oil of reduced carbon residue.

3. Treatment of lubricating distillate from Coastal crude On hundred volumes of lubricating distillate from Coastal .crude petroleum were mixed with twenty-eight voliunes of amylene. This mixture was contacted, with dry hydrogen chloride at room temperature while stirring with 10 per cent by weight of anhydrous aluminum chloride for a.

period of 4 hours. The sludge was permitted to settle and the sour oil was then treated as outlined in the first example. The yield of finished oil was found to be 86.6 volumes having the following comparative tests:

This example shows a great increase in viscosity index attended by an increase in viscosity at 210 F.

4. Treatment of reduced pressure-still tar D One hundred volumes of reduced pressure-still tar of 17.3 A. P. I. gravity and viscosity, S. U. V., of seconds at 100 F., were mixed with 28.7 volumes of uncracked gasoline. This mixture was contacted with dry hydrogen chloride for one hour at 175 F. under 100 pounds pressure. The oil was then stirred at room temperature with 10 per cent by weight 01. anhydrous aluminum chloride for 4 hours at atmospheric pressure while maintaining the presence of an excess of dry hydrogen chloride. The sludge was permitted to settle and the sour oil was then treated as in the first example. The yield of finished This example shows a good yield of oil of fair quality from a tar.

5. Treatment of reduced pressure-still tar lubricating One hundred volumes of reduced pressure-still tar of 16.4 A. P. I. gravity and viscosity, S. U. V., of seconds at 100 F., were mixed with an equal volume of cracked gasoline of 77.4 A. P. I. gravity. This mixture was contacted with dry hydrogen chloride for 4 hours at ordinary tem perature and pressure. The oil was then stirred at 40 F. with 10 per cent by weight of anhydrous aluminum chloride for ten hours at atmospheric pressure. The sludge was permitted to settle and the sour oil was treated as in the first example.

This example shows the improved yields obtainable by the use of cracked instead of uncracked gasoline.

6. Treatment of light gas oil to yield kerosene One hundred volumes of light cracked gas oil from Venezuela crude petroleum were mixed with 20 volumes of amylene and stirred at room temperature with 10 per cent by weight of anhydrous aluminum chloride for 8 hours at atmospheric pressure. An atmosphere of dry hydrogen chloridewas maintained over the mixture during stirring. The sludge was permitted to settle and the sour oil was then distilled with 0.1 per cent by weight of hydrated lime. The yield of finished kerosene was found to be 7 5 volumes having the following comparative tests:

augi Kerosene Gravity: A. P. I 36.5 46.0 Color, Saybo1t. +25 Viscosity, Saybolt thermo-viscosimeter: 400 Flash, '1. C. 0.: F 139 Sulfur (L): Per cent 0. 36 0. 003 Acid heat: "F l Distillation, assay:

Over point: F 374 352 End point: T... 588 550 Percent at 392 F l0 11 500 88 92 590 97 50 percent at: F. 428 435 This example shows an increased yield of high grade kerosene by mutual reaction with amylene during refining.

The above examples illustrate a few of the ways in which our invention may be used to improve technical petroleum products. The operating conditions under which the process is carried out can be widely varied without departing from the spirit of our invention. In many cases the procedure may be varied to suit the particular material which is being treated or the particular product which it is desired to produce. Some of these variations have been outlined in the preceding discussion. Others will be immediately evident to those skilled inthe art.

Reference is made to our copending application, Serial No. 628,446, filed March 18, 1933, which discloses treatment of oil stocks with a halogenated hydrocarbon in the presence of aluminum chlorid.

What we ,claim is:

1. The process of obtaining an improved lubricating oil in high yield which comprises treating a mixture of a-relatively high boiling petroleum stock and a lower boiling petroleum stock.

at a temperature not above about 300 F. with aluminum chlorid in the presence of added HCl to produce a synthetic lubricating oil stock of characteristics intermediate those of the two original stocks and in yield substantially greater than is obtainable by a similar separate treatment of the two original stocks, settling out the bulk of aluminum chlorid sludge tormed, de canting, decomposing the traces of aluminum chlorid sludge'that remain in suspension in the decanted liquid by agitating the oil with dilute sulfuric acid, separating the acid, contacting with clay and filtering.

2. The process of claim 1 wherein sulfuric acid of -5 to per cent strength is employed.

3. The process of obtaining an improved lubricating oil free from impurities and in high yield which comprises mixing a relatively high molecular weight petroleum stock with a lower molecular weight petroleum stock, treating the mixture with aluminum chlorid in the presence of added HCl at a temperature not above about 300 F. to produce a synthetic lubricating oil stock of characteristics intermediate those of the two original stocks and in yield substantially greater than that obtainable by a similar separate treatment of the two original stocks, settling out the bulk of aluminum chlorid sludge remaining in the stock, decanting, decomposing traces of aluminum chlorid sludge remaining in the decanted liquid by heating with a small amount of clay to a temperature in the general neighborhood of 450 F. in the presence of a small amount of. clay and about 0.6 pounds of lime per acid number per barrel and removing the products of decomposition by filtering to secure a refined lubricating oil of the character described. I

4. In the production of improved lubricating oils by treatment or admixed unrefined stocks of difierent hydrocarbons in the presence of alu- 5 minum chlorid to give a synthetic product containing suspended aluminum chlorid sludge, the process of finishing which comprises settling the product of the aluminum chlorid treatment to remove the bulk of the aluminum chlorid sludge 10 therein, decanting, decomposing the remaining aluminum chlorid sludge with dilute sulfuric acid, separating the acid, contacting with clay and filtering.

5. The process of claim 4 wherein the acid 5 strength is about 5 to 20 per cent.

6. In the process of obtaining a refined pure lubricating oil from mixtures of unrefined stocks with the aid of aluminum chlorid the finishing procedure which comprises settling out from the 20 aluminum chlorid treatment product the bulk of aluminum chlorid sludge, decanting, decomposing traces of aluminum chlorid sludge remaining in suspension in the decanted liquid by heating to a temperature in the general neighborhood of 450 F. with a small amount of clay and with about 0.6 pounds of lime per acid number per barrel and filtering to remove products of decomposition, to secure a pure oil of the character described.

EUGENE AYRES. HERSCHEL G. SMITH.

common: or common.

Patent No. 2,019,037. October 29,1935.

' wanna nus, ET no It is hereby certified thnt error eppeers in the printed specitieltioa of the lbovenumbered patent requiring correction as follows: In the drewinzs, Sheet'2, Fig. 2, as shown below should nppenr as I part of the Letters Patent:

Oct. 29, 1935. AYRES 5 AL 2,019,037

MANUFACTURE OF IMPROVED HYDROCARBON PRODUCTS Filed March 10, 1952 2 Sheets-Sheet 2 SLUDGE fl sglnu) AGITATE I g 2 SETTLE 122511301: nusmzn LUBE OIL V CLAY CONTACT FILTER ammo [M3 Eng eize Zyr fiersciegl Q.

and that the said Letters Patent should be read with these corrections therein the! the same they conform to the record of the one in the Patent Office.

Signed and sealed this 26th day of November, A. D. 1935.

Leslie Frazer Acting Commissioner of Patents.

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