US2298347A - Treatment of hydrocarbon oils - Google Patents

Description

Patented Oct. 13,1942 i UNITED STATES PATENT OFFICE' TREATMENT or nrnnocannon ours Ben -B."Corson and George S. Monroerchlcaip,

Ill.,- assignors to Universal Oil Products Company,- Chicago, 115., a corporation 01' Below!!! No Drawing. Application October so, 1939',

Serial No. 301,949 7 1 Claim. (Cl. 196-24) This invention relates particularly to the treatand ester formation of oifinic compounds presment of-hydrocarbon distillates'ofegasol ne boiling ent. Similarly, attempts to desulfurize with sulrange and more specifically to a method of treatfuric acid to meet the usual requirements of 0.10% ment whereby the sulfur content of such distilsulfur caused extremely high losses-and the forlates may be reduced without undesirably afiectmotion of such compounds as suli'onicacids, suling other necessary properties. In some instances fones, sulfur ethers etc, whichremained dissolved the treatment may improve the quality of the oils in the gasoline, and were only partially removed? treated in other ways than reducing the sulfur by treatment with alkalis, clay filtration, or recontent. For example, there may be reductions running of the acid-treated stocks; Desulfuriza-- in actual and potential gum content, 601013811! 10 tion by the use of sulfuric acid therefore was antiknock value. found to have, and still has very limited appli- Desulfurization, is one of the major problems cation. confronting the petroleum industry since many Among the methods which havebeen tried to crude petroleums. particularly those of a napheffect selective .desulfurization of cracked gasothenic or mixed base character, contain such v lines without adversely affecting other properties quantities of sulfur that motor fuels made from of such gasolines, particularly 'antiknock value m y Straight distillation Without cracking, duetoremoval or converslonof unsaturated comand particularly those made bycracking their pounds of relatively high antiknock value, is hyheavler distillates and residua, frequently condrogenation in the presence of catalysts'under tain so much sulfur that their use, without special moderate temperature and pressure conditions; treatment, is impossible since not only do the Heretofore, attempts to desulfurize cracked dissulfur compounds impart a foul odor which is tillates by this method have generally met. with undesirable from a sales standpoi t, but the 1 failure because of the fact that the addition of furous and sulfuric acids formed by oxidation hyd to at rat d hydrpcarbonsapparentof the gasolines in the cylinders of internal com- 1y proceeded concurrently and excessively with bustion engines frequently cause serious crank t action of hydrogen on sulfur eoi" case corrosion, and the sulfur in the unburned various types so that by thetime the ,sulfurrwas gasolines corrodes feed lines, carburetor parts, etc. reduced to the allowable maximum by the forma- Although the limits of sulfur tolerance have been ,tion principauy of hydrogen sulfide 1 raised, due to better ventilation of crank cases, gas), thggntiknok value .of the a l ne h within the last few years. there are Still definite been seriously and permanently impaired by the limits to the total sulfur which .is allowable in saturation of l fim hydrocarbons. 5 5 s gasolines for use in internal combustion engines. been particularly notable in prior attempts 0 When the sulfur problem was first encountered desmmrize, gas 01m 8 boiling range liquids made inmotor fuels, along withv other problems peculiar to by polymerization of olefinsr m hydrocarbon to the treatment of cracked asolines, such as improvement in color and. gum content, the prinmlixmms contammg sulfur COmPWDdSrSmCB cipal treatment in vogue was with sulfuric acid 8 eflns are readilyhydmgeniatedi as a which was generally highly effective in improv- P he Paramniwwnterparts h v lower .aning the color and odor of straight run paramnic 40 tlkmck 1 i difficulty in P i t- ,and mixed base gasolines. But it was found that tempts to'desulfurize w hout serious-lossof antithe use of sulfuric acid was seldom selective in klmck Value hasbeen e r dual, and sometimes improving any one property 'such as color, for pid, deterioration of hydrogenation catalystsexample, if color was improved to a desired-point, employed due to the formationof sulfides having there was frequently large losses due to solution reduced or no hydrogenating activity. It is- 1i-,h-

'gas mixtures over iur as sulfur dioxide and ifimetal oxide-which is later reduced to metal by eventually sulfurized gasolines by means of hydrogenation that the present invention is concerned.

In one specific embodiment, the present invention comprises a process for desuliurizing gasolines containing both olefinic hydrocarbons and sulfur compounds which comprises subjecting the vapors of said gasolines mixed with relatively large amounts of hydrogen to contact with metal sulfide catalysts at temperatures within the approximate range of 250-450 C. and superatmospheric pressure of the order of 300 lbs. per square inch or higher while using relatively low liquid space velocities.

We have found that when using granular metal sulfides catalysts such as, for example, sulfides of nickel; copper, cobalt, iron; chromium. molybdenum, manganese, zinc, tungsten, etc., while observing the conditions or operation specified that cracked gasolines containing both sulfur compounds and olefins can be desulfurized to an extent so that they are readily. marketable without adversely affecting antiknock value. As will be shown in later examples a relatively large excess of hydrogen over that necessary for eiiecting ception of the process complete hydrogenation of the olefins and re sulfur is necessary, .and if antiknock minimized, the degree 01 olefin hydrogenation must be stopped at a definite point the composition of the gasolines to'suliur and olefinic content.

the present invention is not moval of losses are to be fisgzonsidered g be possible that in the pres- .enceifoi' 'a large excess of hydrogen and under the other limiting conditions of operation, the rate of .sdesuliurization: reaction increasesout of proportion the rate of olefin hydrogenation reaction so that. effective sulfur removal is accomplished before undesirable curred. Other possible factors are the rate of olefin hydrogenation has oc- .hydro'genation' of various types of olefins, both normal and isomeric, but

predictab1e,'particularly .;tures inwhich'they occur in 'cracke'd gasoline. a In some instances 4 carbons show greater antiknock after hydro- ;genation tothe corresponding parafiins although this rule lsby no means absolute. Relatively low liquid-space velocities are preferable of the order ot 0.5 to 5 .depending upon the chemical and physical characteristics of these are somewhat unin the complicated mixhighly branched olefin hydrothe gasoline treated. It is to be 11 tedfthat the temperatures and pressuresemployed are of moderate order. t

Using the types of catalysts specified which vary in their degree of effectiveness so that while they maybe used alternatively they are not in.

. any sense exactly equivalent, substantially no difficuities are encountered with catalyst poisoning;

and'operations may be conducted over long periods of time before reactivation to the deposition or carbonaceous materials. After such a point is reached, reactivation is readily practiced by passing air or other oxidizing the spent catalyst to burned the carbonaceous deposits. During this step some of the metal sulfidewill be found-to lose-sulsulfur trioxide to form the hydrogen present during. the operating stages.

is necessary due While it is preferred to start with sulfide catalysts in operating the process, it is comprised within the scope of the invention to start with metals which are gradually suliurized during the process or deliberately sulfurized prior to the inby passing hydrogen sulfide or some other decomposable sulfur compound, either inorganic or organic, through the granular material. The catalytic materials may be employed on carriers or spacing agents of a relatively inert and usually siliceous refractory character. Besides frequently used siliceous carrying materials such as diatomaceous earth, clays. bentonites, montmorlllonites, both raw and acid treated, crushed refractories etc., other carriers such as properly prepared alumina, chromium oxide, titanium oxide, cerium oxide, thorium oxide and zirconium oxide, and even high melting point salts such as calcium phosphate, aluminum phosphate, etc. may be used.

A convenient method of preparing suitable catalysts consists in precipitating metal hydroxides or carbonates on a support suspended in a solution of a metal salt to which a precipitant is added, the deposited compound being later reduced to metal which is later sulturized, or the hydroxide or carbonate, etc. may be directly sulfurized without intermediate reduction. It is also comprised within the scope oi the invention by precipitating metal sulfides directly upon suitable granular supports or by incorporating metal sulfides with finely divided supporting materials followed by pelleting or otherwise forming of the particles of usablesize. As a further alternative, preformed supports may be impregnated with metal salts and these composites suiiurized by any necessary method to range previously unsaturated To illustrate the produce a usable catalyst.

' In the general operation of fur-containing gasolin is vaporized, mixed with a relatively large excess of' hydrogen or gases having a high hydrogen content, and the mixture is preheated to a temperature within the specified and passed over granular catalysts at -a rate determined by trial to produce the best results. It is to be recognized that each charging stock will require a difierent combination of operating variables to produce optimum results in respect to decomposition oi organic sulfur compounds and hydrogenation of hydrocarbons. The invention is not type of apparatus but found to be suitable, type orv of special limited to any particular may utilize any of those either those of conventional design.

type of results normally obtainable in the operation of the present process,

the following examples are introduced but withdata presented.

out the intention of unduly limiting the scope of the invention in exact correspondence with the A gasoline was treated had been pro- '1 duced by catalyticaliy cracking a gas oil distillate from an East Texas:

Whatever metal sulfide is crude oil. Vapors oi! the gasoline at a temperature of 350' C. (662' F.) were injected into hydrogen at the same temperature under a pressure or 900 lbs. per square inch and passed over a nickel supported nickel sulfide catalyst at a liquid space velocity of 1. The following tabulation shows the results obtained in a run made to determine the degree of olefin hydrothe process, sul- V The following tabulation of data summarizes genation which could be tolerated before appreciable loss in antiknock value occurred.

The catalyst employed in the run which furnished the above data was incompletely sulfurized at the outset of the run and therefore apparently had too high an activity so that exces sive hydrogenation of the olefins occurred with a corresponding drop in octane number as shown after the fifth period of operation. As the catalyst became more highly sulfurized the octane number in the produce was regained while the sulfur was still being reduced notably. The following data shows the comparison of properties of the charging stock and the produce being produced at the end of the run:

Chg. Stk Product Ind. period, oxygen bomb test, minutes 55 l, 4440+ Copper dish gum, mgJlOO cc 60 11 A. S. T. M. gum, g./l cc 7 3 Color, Saybolt Yellow 27 Color stability Yellow 19 Doctor test Positive Negaive EXAMPLE II Desulfurization of California cracked gasoline Exploratory runs Operating conditions;

Tcmperature,(l.. Temperature, "F Hydrogen pressure, lbs/so. Liquid space elocity per hou Bromine number:

Original charge.. Product Sulfur, weight percen Origlnalchnrge. lroduct Hydrogen, cu. itJbbl.

Hydrogen consumed by sulfur Hydrogen consumed by oleiin l7l Hydrogen consumed, total En: hydrogen from plant ZJO i,

runs using optimum conditions:

Desulfurization of California cracked gasoline, using optimum conditions as predicted from exploratory runs Operating conditions:

Temperature, C 350 350 Temperature, "F 662 662 Hydrogen pressure, lbs./sq. in 300 300 Liquid space velocity per hour 1. 3 2. 7 Original charge:

63 63 l. 17 1. 17 72 72 Octane number+l cc. T. E. L. 75 75 Octane number-H3 cc. T. E. L 77 77 Product:

Liquid yield, volume percent. 96 98 Bromine number 21 l 47 Sulfur, weight percent... 0.05 l 0. 21 Octane number 69 73 Octane number-H cc. '1. E. L 76 78 Octane number+ 3 cc. '1. E. L 81 81 Hydrogen:

Hydrogen consumed by sulfur, cu. lt.lbbl. 35 30 Hydrogen consumed by olefin, cu. ftJbbl 310 116 Hydrogen consumed, total cu. ft. bl 845 146 Exit hydrogen from plant, cu. ft./bbl

1 Tetreethyl-lead.

* 677 hydrogenation of olefin 25 hydrogenation of olefin;

96% Desuliurization.

| 82% Desulfurization.

Several points can be noted from the above tabulation of data, particularly that it was possible to reduce the sulfur content from 1.17% to 0.21% with only 25% olefin hydrogenation, the octane number being one point higher than in the original charge, possibly due to the removal of sulfur compounds which had a pro knock tendency, and/or the selective hydrogenation of oleiins whose paraiiinic counterparts possess high antiknock value. The sulfur could be reduced to the negligible value of 0.05% with the loss of 3 octane number (72 to 69) with only 67% of olefin hydrogenation. The high susceptibility of the product to tetraethyl lead was also noticeable. In the runs given above the hydrogen excess was approximately 4 times that required for complete saturation of oleflns and reduction of sulfur to hydrogen sulfide.

We claim as our invention:

A catalytic hydrogenation process for eifecting substantial desulfurization of a gasoline con-' taining both olefinic hydrocarbons and sulfur compounds and hydrogenation of oleflnic hydrocarbons to an extent not materially reducing the anti-knock value of said gasoline, said process comprising subjecting vapors of said gasoline to contact with a heavy metal sulfide in the presence of an amount of hydrogen approximately four times that required for complete hydrogenation of said olefinic hydrocarbons and said removal of sulfur and at a temperature of approximately 350 0., under a hydrogen pres-