2,413,312 Patented Dec. 31, 19.46 UNITED STATES PATENT OFFICE 2.413.312 CATALYTIC FINISHING 0F GASOLINES Robert M. Cole, Oakland, Calif” assignor to Shell Development Company, San Francisco, __Calif., a corporation of Delaware No Drawing. Application January ‘26, 1945, Serial No. 574,755 5 Claims. (Cl. 196-28) 1 This invention relates to the treatment of thermally cracked gasolines, catalytically cracked gasolines, thermally reformed gasolines, and sim ilar materials of the gasoline boiling range con taining substantial amounts of ole?ns and other unsaturated bodies and other impurities such as sulfur compounds, nitrogen compounds, etc., to 2 contain appreciable amounts of sulfur compounds, nitrogen compounds, and other impurities. They have poor color stability, poor gum stability and poor lead susceptibility. Consequently these stocks generallywrequire some sort of ?nishing treatment to make them acceptable for use'in gasoline of present-day quality. The conven effect a substantial desulfurization and to remove or render innocuous various gum-forming bodies.‘ tional method of re?ning these materials is the an improved process for the treatment of various saturated blending materials for premium grade conventional sulfuric acid treatment followed by More particularly the invention relates to the 10 a Doctor treatment and rerunning. This method treatment of such materials by the combined has the recognized disadvantages of incomplete action of hydrogen and catalysts under such con sulfur removal, high acid consumption, poor ditions and in such a manner as to afford the V yields, and an appreciable depreciation of anti desired ?nishing or re?ning treatment with a knock properties. In view of these disadvan minimum loss of material, minimum consumption 15 tages considerable attention has been given to of hydrogen and with substantially no deprecia the catalytic ?nishing of such materials by cata tion of the anti-knock characteristics of the orig lytic hydrogenation. Certain such processes have ' inal material. been proposed. However, the proposed processes ‘_ In my copending application Serial No. 569,234, have certain disadvantages and furthermore are ?led December 21, 1944, of which this applica 20 too costly to make their use economical except tion is a continuation-in-part, I have described in the special case of preparation of substantially sulfur-bearing gasoline stocks including various cracked and reformed stocks with hydrogen for aviation gasoline. . The present process provides a means for ef the primary purpose of effecting desulfurization 25 fecting excellent desulfurization and re?ning thereof without loss of anti-knock properties. while a?'ording a. product of excellent anti-knock The process of said copending application is re characteristics. These desirable results are fur stricted to the treatment of such stocks as con thermore obtained with a minimum consumption tain more than 0.10% sulfur and is restricted to of hydrogen and with improved catalyst life. the use of particular catalysts. The process of v30 Consequently the process of the invention is ap the present invention is an improved process plicable and particularly advantageous for the directed speci?caliy to the treatment of unsatu catalytic ?nishing of motor gasolines of substan rated gasoline fractions such in particular as tially full boiling range and similar ‘non-premium cracked and reformed gasolines in a different and products. particular manner to achieve the above men 35 . The process of the invention in its broader tioned objects. The material treated may or may more general aspect comprises treating the gaso not contain more than 0.10% sulfur. Also, other line in the presence of an excess of hydrogen catalysts than those speci?ed in the above men _ and a sulf-active hydrogenation catalyst at a tioned copending application may be used. When temperature between about 400° F. and 825° F. treating such cracked stocks containing more 40 under conditions adjusted to give only a partial than 0.10% sulfur with the particular catalysts speci?ed in said copending application according to the process of the present invention, however, the process depends in part upon the principles disclosed in said copending application. Gasolines produced by thermal cracking, gaso lines produced by catalytic cracking, and gasolines produced by thermal reforming of various gaso line stocks usually have the following character istics: They contain appreciable quantities of desulfurization and to hydrogenate only a minor part of the ole?ns, separating- the partially de sulfurized material into a lower boiling fraction and a higher boiling fraction, treating the'higher boiling fraction in the presence of an excess of hydrogen and a sulf-active hydrogenation-dehy drogenation catalyst at a temperature between about 850° F. and 1000° F. under conditions ad justed to effect substantial desulfurization and substantial saturation of ole?ns, and blending ole?ns and other unsaturated bodies and con the ‘product of the latter treatment with the lower sequently have a high bromine number and high boiling fraction to produce an ole?n-containing acid heat. They contain appreciable quantities desulfurized‘?nished gasoline having an octane of aromatics and naphthenes. They have rela number at least as high as that of the original tively good anti-knock characteristics. They 55 starting material. In a more speci?c embodi - ' 2,413,812 I ment of the process at least the major portion of the hydrogen required for the ?rst, or low temperature, treating step is obtained from the second, or high temperature, treating step. In a further more particular embodiment the con 4 300-400° F. fraction of the product is 0.10% or slightly below 0.10%. The ?rst index is prefer ably used when a catalyst other than a sul?de of a metal of the iron group is used in the second, or high temperature, treatment and the second index is preferably used when the catalyst in the second, or high temperature, treatment is a sul ditions in the ?rst, or low temperature, treating step and the cut point in the separation are ?de of a metal of the iron group. adjusted such that the higher boiling fraction The partially desulfurized material from the of the product 01' the ?rst step contains in the order of 0.10% sulfur and catalysts of a particular 10 above-described low temperature treatment is separated into a lower boiling ole?nie fraction type are employed in the second, or high tem and a higher boiling ole?nic fraction. The sep. perature, treating step. ' aration may be effected at any convenient point The process is generally applicable for the cat according to. the character of the material, but alytic ?nishing of various sulfur and ole?n-con the split between the fraction is preferably made taining distillates such as motor gasolines ob between 200° F. and 300“ F. When employing a tained from thermalcracking, thermal reform sul?de of a'metal of the iron group as the catalyst ing, catalytic cracking and similar high temper ature treatments, and is designed to re?ne or ?n-v _ in the second, or high temperature, treatment the split is preferably made such that the higher ish such materials to the extent of e?ecting a substantial desulfurization and rendering them 20 bo’ling fraction contains about 0.10% sulfur. Otherwise the split is preferably made at the acceptable with respect to such properties as lead higher end of the range consistent with a satis susceptibility, gum-forming tendency and color. factory sulfur content of the lower boiling frac The treatment,- however, is not designed to give a tions. substantially saturated product having a low acid The higher boiling fraction is then treated with heat and is not recommended for the production an excess of hydrogen and a sulf-active hydro or premium grade aviation gasoline. On the oth genat’on-dehydrogenation catalyst at a tempera_ er hand, the treatment is designed to produce turein the range of 850° F. and 1000" F. A large stable acceptable products having large amounts excess of hydrogen such as from 5 to 30 moles per of ole?ns, such as desired for motor gasoline. mole of hydrocarbon is recommended. The pres The material treated may be a full range gaso sure is usually between about 500 and 1100 p. s. i. line or it may be a gasoline blending stock boiling The catalyst used in this step may be any one of essentially in the gasoline boiling range. the known suit-active hydrogenation-dehydro The material to be treated is ?rst mixed with a genation catalysts. However, in order to a?ord large excess of hydrogen and subjected to a very a substantially continuous operation a sul?de cat mild desuli'urization-hydrogenation treatment in alyst is preferred. Particularly suitable catalysts the presence of a sulf-active hydrogenation cat comprise a sul?de of a metal of the iron group, alyst. In general the amount of ‘hydrogen em if desired in combination with a sul?de of a ployed is between about 5 and 30 moles per mole metal of group VI of the periodic system of the of the hydrocarbon feed. The pressure is usu elements. Examples of such catalysts are nickel ally between about 200 and 1000 p. s. 1. Any of 40 sul?de, iron sul?de and cobalt sul?de, alone and the many known sulf-active hydrogenation cat in combination with sul?des of molybdenum or alysts may be employed in this step. Examples tungsten. These catalysts may be used substan of such suitable catalysts are the oxides and sul tially continuously in the present process for hun ?des of V, Cr, Mn, Fe, Co, Ni, Mo, W. The tem dreds of hours without regeneration. Further perature in this step is maintained between about more, they are particularly e?lcient in e?ecting 400° F. and 825° F. Within this temperature reactions leading to the production of increased range the lower temperatures consistent with the amounts of aromatic hydrocarbons in the prod activity of the catalyst and the other treating uct. When using these preferred catalysts the conditions are preferred. Thus, in general, with ?rst,‘ or low temperature, treatment and/or the a catalyst of average activitya temperature in fractionation are adjusted so that the feed to the neighborhood of 500-600° F. is generally pre the second, or high temperature, treatment con ferred. Under these conditions the material tends' . tains not more than about 0.10% sulfur. to become completely hydrogenated to a satu The high temperature treatment is carried out rated non-aromatic product of-low octane num- , .ber. This is prevented, however, by e?ecting the treatment ~at such a rate that only a super?cial hydrogenation is e?ected. This super?cial hy relatively slowly, liquid hourly space velocities in the'order of 0.5 to 3 being typical. Under these conditions the ole?ns are substantially hydro genated, further desulfurization is e?ected, and considerable dehydrogenation of hydroaromatic drogenation under these relatively drastic condi tions effects a substantially complete removal of naphthenes takes place. gum and color-forming bodies and e?ects a par 60 In the second, or high temperature treatment tial removal of sulfur compounds and nitrogen appreciable amounts of hydrogen are produced by compounds, but hydrogenates only a small the dehydrogenation of naphthenic constituents. amount of_ the ole?ns present and does not at tack the aromatic hydrocarbons at all. The ex- ' This hydrogen provides a considerable portion of tent of this treatment is adjusted, preferably by 65 the hydrogen required for the treatment andin some cases may supply hydrogen also for the ?rst, controlling the throughput rate and/or the tem or low temperature, treatment. The hydrogen perature to one of the following criteria or in gas recycled to the treatments to maintain the dexes of treatment, depending upon the sulfur desired excess hydrogen may be treated by con content of the feed stock, the cut point in the following separation, and the type of catalyst used in the second, or high temperature, treating step. (1) The conditions are adjusted such that the sulfur content of the IOU-300° F. fraction of -the product is about 0.10%. (2) The conditions are adjusted such that the sulfur content of the 75 ventional methods to remove the hydrogen sul ?de formed in the process. An advantageous cycle is, for example, to pass the hydrogen gas separated from the product of the second, or high temperature, treatment to the ?rst. or low tem perature, treatment; treat the hydrogen gas sep 2,418,812 arated from the‘ low temperature treatment to remove hydrogen sul?de; and to cycle the hy- I: drogen from the hydrogen sul?de removal step to the second, or high temperature, treatment. . 6 _ _ oi’ the feed under the higher temperature condi tions as in step 2, (5) treating the lower boiling material alone as in step 1 and treating the higher boiling material alone as in step 2. When operating in this manner, it is advanta I claim as my invention: 1 geous to add any fresh hydrogen required to the 1. Process for the catalytic ?nishing of sulfur second, or high temperature, cycle. containing ole?nic gasolines which comprises The product of the high temperature treatment treating the gasoline in the presence of an excess is reblended with the lower boiling fraction. The hydrogen and a sulf-active hydrogenation cat blend, ‘or the separate fractions, may be caustic 10 of alyst at a temperature between about 400° F. and washed to remove traces of hydrogen sul?de. 825° F. under conditions chosen to e?‘ect only a The blended product normally meets all of the partial desuliurization and to hydrogenate only usual requirement regarding gum stability, color, a minor part of the ole?ns, separating said par etc. It has an octane number (A. S. T. M.) at tially desulfurized material into a lower boiling least as good as that of the original feed and 15 ole?nic fraction and a higher boiling ole?nic ‘ usually considerably better. Also the lead sus ceptibility is greatly improved. The hydrogen fraction, treating said higher boiling fraction in the presence of an excess of hydrogen and a consumption-is generally very small since only a suit-active hydrogenation-dehydrogenation cat portion of the ole?ns 'are saturated. The yield oiproduct, based on the feed, is in the order of 20 alyst at a temperature between about 850° F. and 1000° F. under conditions chosen to effect sub 96-99%. stantial further desulfurization and substantial It will be noted that in the above-described _ saturation oi.’ ole?ns, and blending the product process the higher boiling portion of the feed is of said second treatment with said lower boiling treated twice under different conditions. The fraction‘ to produce a re?ned ole?nlc gasoline ?rst treatment of this material is e?ected at a low 25 having an octane number at least as high as the temperature in the presence of the lower boiling original‘starting material. / portion of the feed and the second is e?ected at a 2. Process according to claim 1 in which a higher temperature in the absence of the lower sul?de 01' a metal of the iron group is employed boiling portion of the feed. This particular man as a catalyst in the second or higher temperature ner of operation is found to give results which 30 treatment. are much superior to various alternative one and 3. Process according to claim 1 in which a com two step processes such, for example, as the fol bination nickel sul?de-tungsten sul?de catalyst lowing: (1) treating all of the material under the is employed in the second or higher temperature low temperature conditions as in step one, (2) treatment. treating all of the material under the high tem 35 4. Process according to claim 1 in which the perature conditions as in step 2, (3) treating all split between the lower and the higher boiling of the material under the low temperature condi fractions is made between 200° F. and 300° F. tions as in step 1 followed by treating all the ma 5. Process according to claim 1 in which the terial under the high temperature conditions as severity in the ?rst or lower temperature treat- ' in step 2, (4) treating the higher boiling portion 40 mentis adjusted so that the sulfur content of the , of the feed under the low temperature conditions _ higher boiling fraction is about 0.10%. as in step 1 and treating the lower boiling portion ‘ ROBERT M. COLE.