US1748507A - Process of producing stable hydrocarbon oils - Google Patents

Description

wreazsim' NI E STATES Him 1'. BROOKS, OI SOUN'D BEACH, OON'HEQIICU'I, ASSIGNOB TO THE GRAY- PATENT" .QFFICE comma-10x, or mm, m smear, a coaroaarron or minameme 0] PRODUCDIG STABLE HYDBOOAR'BON OILS Io Drawing.

This invention relates to the art ofoil reand more particularly to the treatment rf light hydrocarbon oils having a tendency o discolor during storage and distribution mch as certain types of gasoline, or motor fuel, and kerosene, to improve the color stability thereof.

An object of this invention is to provide an mproved process of treating such substances n a convenient, eflicient and economical manner.

A more specific object of this invention is 0 reduce substantially colorless light hydroasion oils having an improved stability as 0 color and sedimentation so that they will emain colorless and clear, throughout an exended period of ex osure to sunlight, air and moderately elevategtemlperatures such as are ncountered commercial y during storage and listribution.

Qther objects of the invention will in part igtgbvious and will in part appear herein- L r. a I

The invention accordingly com rises the everal steps and the relation an order of me or more of such steps with respect to each f the others, and the product essing the Features, pro es, and the re ation of contituents,wh1ch are exemplified in the followng detailed disclosure, and the scope of the lfiplication of which will be indicated in the The commonly accepted uirements of good commercial grades of gaso 'ne and kerolene are that they shall not only be substanially colorless at the com lotion of the rep but that ey shall remain :olor ess and ear throughout the somewhat axtended period of storage which usually enmes prior to their sale to the ultimate conrumer. this interval certain of even :he most care y refined oils have heretofore entlyl developed discoloratioili of a ct .owish, p e orange, or more rare y, p s :haracter, and this change has often been lccompanied by the development of a cloudy :pgearance and formation of a deposit or l'ment which is usually dark brown in :0 or.

Such discoloration and sedimentation se- Application filed October 10,1985. Serial- No. 81,816.

riously depreciates the market value of such products, and in petroleum refinery ractice, 1t is customary to test the refined gaso inc and kerosene for stability-by subjecting samples thereof in suitable receptacles to the action of sunlight, air, and moderate heat whereby the changes normally occurrin during storage are accelerated. The oils w ich stand a test of exposure in colorless glass bottles to direct sunlight for several days or of heating for several hours to about 212 F., are considered to be of good quality, since experience has shown that they usually do not become discolored durin storage.

This objectionable discoloration has been encountered more seriously with gasoline and kerosene manufactured by so-called crackmg processes than with the similar oils obtained from crude tillation and whic are commonly known as straight-run products, although it is well troleum by ordinary disrecognized that gasolines and kerosenes which have been refined by any of the methods now in common use are likely to become discolored. Moreover since the causes of this color instability have not heretofore been understood, the attempts to overcome the difliculty have been varied in character and usually ineflicient and costly of application. Examples of such attempts are the re-refining of such oils by filtering through fullers earth, decolorlzlng charcoal and the like or redistillation of the oil usually with the aid of steam.

Straight run lines and kerosenes are sometimes refine by'agitatin with an alkaline solution of sodium plum ite, acid treat ment being omitted. Gasolines treated in this we frequently become discolored, particular y if sulfur is added to the alkaline lumbite and gasoline mixture. In the case 0 kerosene it is common practice to filter the refined kerosene through fullers earth, bauxite or other decolorizlng a nt to remove coloring matter. When freshly refined such gasohnes and kerosenes are colorless and entirely free from traces of acid and alkali, bu. may rap-- idl become discolored during stora ore frequently the practice of g petroleum oils has included the well known steps of treatment with sulphuric acid, water,

alkali and sweetening agent and in the case of cracked gasolines the chemically treated gasoline or pressure distillate is redistilled. t is possible withproper crackingand rectifying apxparatus, to roduce a pressure distlllate w ch has a 150' 'ng point range of ordinary gasoline, the chief objection to such practice has been the nty of redist' standing-or in the sunl' t or heating tee It has alsobeen founy thatorganic nit1 gen bases or derivatives of annnonia,, whi are erally more soluble in h drocarb oils an gaseous ammonia, are efiecti 1n p'reventm discoloration. Of these game bases, 1t 1s, eferred to employ tlu 111mg which do not readily form colored oxidati these oils after refining color-table product.

By the present invention, it'has been found that the discoloration of hydrocarbon oils ha a tendency to discolor during storage and ribution, such as certain addition -of certain e or basic substances to freshly prepared neutral oils as roduced by the customary refimf methods. -thaslongbeenrecognised,in erefining 2o olfapetroleum oils, that all traces of free mine acids, such as sulphuric acid or sulphuric dioxide, used in the refining rocess, should be .thorou hly removed by e above mentioned w with water and neutralization as with alka'lies prior to the final distillation of the oil; the prewnt invention is to be particularly distinguished from such old ractice.

-Intheimprovedprocessofo a color-stable .roduct, comprisin the present so invention, it been found desirable to com- 10 with the freshl prepared refined oil an line or basic su ce which will remain in the refined oil during storage and will efiectivelyneutralize or overcome either 85 an slight traces of acid which might be initi y present therein after the last distlllation and more particularly the acids which I find develop or tend to develop therein during such stora it being preferred, however, to 40 add the 'ne substance in amounts such that at the end of the storage period there is substantially no free excess of the e agent. This discoloration is due rhaps to the presence in the refined oil 0 inorganic 4s substances, such as free sulphur, or of organic substances of'a more or less complex nature, which may yield acids by slow decomposition, oxidation or hydrolysis.

Althou h in the accomplishment of this re- 60 sult, alkaline substances of-a relatively oilinsoluble nature such asllligdratedlime, calcium carbonate and the e mi ht be used, it has been found to be preferab e to use oilsoluble bases such as ammonia or certain of 55 its alkaline compounds or derivatives. A1-- thou h ammonia is nerally considered to be inso uble in miner oils, it has been found that it is sufliciently soluble in light hydrocarbon oils to have the efiect of preventing discoloration and that, although gasoline is capable of taking up or dissolving about 3 grams of anhydrous ammonia per gallon, at 20 C., usually 0.5 grams more or less of ammonia (NI-1,), per gallon is suflicient to revent discoloration or sedimentation on ong in order to obtain a,

' m1ne, trimethyl amine,

15 and kerosenes, is efiectivel prevented by the oils and that by the use of' the cases to simplify or curtail or condensation products such as benzyi ethylamine, pop I mine and the aliphatic p secon a and tertiary amines generally. t has herel fore been suggested to add 'amiline or 0th aromatic aunnes to a refined h drocarbon order to reduce motor knock and to eiln nate the deposition of carbon in the comb\ tion chamber. Since these latter substam tend readily to form colored oxidation a: condensation products they are not suital for use to accomplish the purpose of the pn ent invention, and by the-use of the term 0 or-stable in the present claims it is intend to exclude such substances. 7 a

It has been found that the present inve tion may be successfully ap lied to light 11 drocarbon oils such as e and kerose having a tendency to discolor dur' store and distribution, even when refined any the methods now employed in refining su principlesthe present invention it is le in mm A e series of o ations heretofore considered-n ry. example',- it has been found in the case of t' refinmggf cracked oils, that the final distill tion a r the sulphuric acid, water,.alka and sweetening treatment need not be ca ried.out if a basic substance is added to t? rgfined and, neutralized oils,"as describ a ve. a

The following" examplesillustrate the ma ner and eflectiveness o the application of t] resent invention to various types of gas One-half on of crude cracked gasolil was refined agitating with concentrau sulphuric aci in the roportions, of fi pounds of acid per 42 one of oil, the ac andtar separated, the oil washed with wet and an excess of caustic soda and then swee ened by agtating with sodium lumbi solution. 0 gasoline thus refin was d vided into two portions, to one of which an monia was added in thelgroportions of abol 1.5 grams per gallon. th the neutral p0: tion and the portion containing ammom' were then explosed to direct sunlight. Whi the color of t e original, refined gasoline we 23 on the Saybolt color scale, the portio treated with ammonia retained this colc after two days exposure to sunlight, the ne1 tralized oil containing no ammonia darl ened in color in three hours to about 15 o the Saybolt scale, and at the end of the tw days had become too dark to measure on th iybolt scale and had formed a nearly black :posit of insoluble matter. 7

A straight run gasoline, distilled from a 'ude petroleum, was refined by sweetening 11y, acid treatment being omitted, as is often 1e practice with gasolines of this type. :alf a gallon of this gasoline was sweetened alkaline plumbite solution and a portion E the oil so refined was treated with am- ,onia in the proportion of .6 gram per gal- In; both portions were then exposed three ays to direct sunlight, at .the end of which me the portion treated with ammonia lowed a color of on the Saybolt scale, 1e same as the original color, and the poron containing no ammonia had become yelw in color equivalent to about 17 on the aybolt scale.

One half gallon of straight run gasoline as agitated with dilute calcium hypochloite solution until sweet to the alkaline plumite reaction. The product so treated was ivided into two portions, one of which was 'eated with ammonia in the proportions of .5 gram NH per gallon of oil, and no furier treatment was given the other portion. ioth samples showed 25+ color on the Sayolt scale but after two days exposure to irect sunlight the one containin ammonia amained colorless but the one without amlonia had become yellow in color to the exant of about 19 on the Saybolt scale.

In practicing the invention on an indusrial scale, it has been found to be convenient prepare gaseous ammonia by adding conentrated aqueous ammonia to solid caustic lkali such as caustic soda, whereby nearly ry ammonia gas is evolved; quickhme may e used in the same way, but the ammonia not so dry. The oil may be agitated with oncentrated aqueous ammonia and the aqueus layer, still containing most of the amionia, then separated, but this is of course, wasteful of ammonia. A preferred proce- .ure, adapted to treating large volumes of il, 1s to release gaseous ammonia from a ylinder of anhydrous ammonia, by means f a suitable reducing valve, and pass the mmonia gas at a controlled rate into the oil. The gas may be passed continuously into a tream of the oil as it passes to storage, or a ar e tank of refined gasoline may be treated iy ubbling the gas into the oil near the botom.

When a liquid base such as trimethyl amine s employed, it is necessary merely to add a measured quantity of the base to a definite plume of the oil in any way providing for )roper mixing of the liquids. As with amnonia, the quantities required will depend omewhat upon the purity of the oil and upon ts tendency to discolor but the amounts necessary to effect color-stability are within he range 0.5 to 5 grams per gallon for most IXJIDPIBS of such oils; a very badly refined oil or one exceptionally rich in impurities, may require a somewhat larger amount.

Since certain changes in carr ing out the above process, and certain mo ifications in the composition which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebe tween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

. 1. A process for stabilizing the color of gasoline which comprises treating a freshly prepared and chemically refined gasoline with ammonia in an amount from about 0.5 grams to about 1.5 grams ammonia per gallon of gasoline treated.

2. A process for stabilizing the color of gasoline which comprises treating a freshly prepared and chemically refined gasoline with ammonia in an amount of about 0.5 grams ammonia per gallon of gasoline treated.

In testimony whereof I atfix my signature.

BENJAMIN T. BROOKS.