Patented Dec. 24, 14946 ’ 2,413,105 UNITED STATES." PATENT OFFICE ALKYLATION OF HYDROCARBONS George B. Hatch and Ernest F. Pevere, Beacon, . Louis A. Clarke, Fishkill, and Frank H. Bruner. Beacon, N. Y., assignors, by mesne assignments, to The Texas Company, New York, N. Y., a cor-y poration of Delaware Original application August 30, 1939, Serial No, 292,582. Divided and this application January 7, 1941, Serial No. 373,416 10 Claims. (Cl. 260-—683.4) . 2 - 'l . Cs and C4 ole?ns, for the production of high This invention relates to the alkylation of hy anti-knock gasoline hydrocarbons.~- . ' drocarbons and particularly to the alkylation of In carrying out the alkylation treatment in a isopara?ins with ole?ns in the presence of a liquid continuous manner it is usual to'pass the hy-v or ?uid catalyst for production of gasoline, and drocarbons to a tower or reaction vessel wherein has to do particularly with the operation of an (1 ‘they are subjected to alkylation whilein ‘con-f, . alkylation process. tact with .an alkylation catalyst, such as con-‘ The present application is a division of Serial centrated sulphuric acid, under predetermined _ _ . No. 292,582, ?led August 30, 1939, for Alkylation conditions of temperature and time of; reaction, of hydrocarbons, now Patent No. 2,267,097, dated conccntration of acid, and ratio‘ of acid to hydro: 10 December 23, 1941. carbons. The invention has to do with an alkylation are introduced to a reaction vessel and therein subjected toalkylation in the presence of a cat alyst such as concentrated sulphuric acid, hy I I 5 ‘ drocarbons, as well as unreacted. hydrocarbons, and an'acid layer comprising usedacid. alysts, either with or without a promoter. Ac cording to the invention a mixture of hydrocar bons and catalyst is continuously ‘withdrawn from one portion of the reaction vessel and re .1 The reacted mixture is drawn offin a continu ous stream and introduced’ toa 'settlingves'sel; where strati?cation occurs, with the formation of a hydrocarbon layer comprising alkylatedihy process wherein ole?n and paraf?n hydrocarbons * drated borontri?uoride and other alkylation cat , I All or ; a portion of the used acid may be recycled to the reaction vessel, while the hydrocarbon, layer a 20 is subjected either to further contact with the catalyst in a subsequent stage, or else neutral cycled to another portion under conditions of ized and fractionated to remove the unreacted. high velocity ?uid flow so asto impart a high hydrocarbons, such as isopara?ins, whichare re- _ ‘degree of agitation or turbulence to the ?uid turned to the system for alkylation with addi contents of the vessel. Thus, a stream of hydrocarbons and catalyst 25 A portion- of the reacted mixture drawn off comprising products‘of reaction may be contin from the reaction vessel may be recycled directly uously Withdrawn from the top or upper por to the reaction vessel without subjecting it to‘ tional tion of a vertical reaction vessel and a prede termined portion thereof recycled to. the reac tion vessel. That portion not recycled is sub jected to settling so as to stratify and form a hy drocarbon layer and a catalyst layer. The by drocarbon layer is removed and subjected to such further treatment as may be desired, while the catalyst layer is withdrawn and at least a por tion thereof also recycled to the reaction vessel. An important object of the invention involves withdrawing from the bottom or lower portion of the reaction vessel a portion of the liquid con tents and returning this withdrawn liquid in, a stream or streams ?owing under high velocity'so as to impart suf?cient agitation to the contents of the reaction vessel in order .to'avoid forma tion of relatively stagnant pools of liquid cata ole?ns. > settling, as above described. 30 r ,_ . . . In such an operation there is a tendency for ' settling or‘ strati?cation to ‘occur within there action vessel, due to the difference in specific". gravity between the hydrocarbons and the alkyl~ ation catalyst, for example,’ concentrated sul 35 phuric acid. As a result; the acid tends ~to be' concentrated in the bottom-or lower portion of 1 the reaction vessel, due to settling. ‘Relatively stagnant pools of acid may-"thus; accumulate within the lower portion of the vessel, and this 40 is undesirable, from the standpoint of realizing, the most e?icient use of the catalyst and also the avoidance of either under or o'ver-treatment’of .certain constituents'of the hydrocarbons. Accordingly, the present invention involves re ducing the amount of settling and concentra 45 lyst within the vessel. tion of acid within the reaction vessel by continu; f vIn an alkylation process it ,is essential to I ously removing some of the concentrate from the achieve this object in order to realize e?icient lower portion of the vessel, mixing with feed hy~f use of the catalyst, as well as to avoid catalyst drocarbons and introducing‘the mixture‘to an~ deterioration, and also/in/o der to avoid over other portion of the vessel in a highlyturbulent. treating certain constituen s and under-treat 50 state. It also involves maintaining efficient agi-, ing other constituents of the hydrocarbons un dergoing treatment. a The invention is of particular application in the alkylation of low-boiling isopara?lns, such as isobutane or isopen'tane, with ole?ns, such as 65 tation within the vessel. 1 -. I p . v . The invention 'will be understood more fully by reference to the ?gures of the accompanying . .' drawing. _ - ~ 1 i. . 3 2,413,105 The drawing illustrates, in each ?gure, a single reaction unit comprising reaction and settling vessels, although it is contemplated that a plurality of such stages may be employed, using in each stage the method or methods of recycling described herein. As indicated in Fig. 1, the reaction vessel com prises a tower | and wherein the ole?n and iso para?ln hydrocarbons are subjected to contact with a catalyst, such as 'concentrated'sulphuric acid. The liquid mixture of unreacted hydro 4 , controlled ori?ce 22, controlling the proportion of the drawn-off mixture passing to a settler 23, similar to the settler 3 described in connection with Fig. 1. That portion of the withdrawn mixture not passing to the settler 23 ?ows through a pipe 24 communicating with the suction side of a pump 25 and by which means it is reintroduced to the I lower portion of the reaction vessel 20. Catalyst with some hydrocarbon accumulating in the bottom of the reaction vessel 20 is with carbons, alkylate and catalyst, accumulating in drawn through line 26 by a pump 21, which dis the top of- the vessel, is continuously drawn o? charges this liquid through a nozzle or nozzles through a conduit 2, leading to a settler 3. . _ 28, discharging into the upper portion of the The settler 3 is advantageously of conical reaction vessel 20. shape, as indicated, so as to facilitate removing Feed hydrocarbons, together with recycled iso the separated catalyst from the hydrocarbons as para?in hydrocarbons, are introduced to the rapidly and as completely as possible and there suction side of the pump 21 through a pipe 29. by to reduce to a minimum the time of‘c‘ontact‘ Used catalyst, withdrawn from the bottom of between catalyst and hydrocarbons after intro 20 the settler 23, together with any makeup catalyst, duction to the settler. is conducted by a pipe 3|! communicating with The conduit 2 contains an ori?ce or ‘valve 4 the pipe 26, leading to the suction side of the adapted- to control the amount of liquid mix pump 21. . ture passing to the settler 3. That portion not Thus, one feature of the method of flow 11 passed to‘ the settler 3 is by-passed through a 25 lustrated in Fig. 2 involves the realizing of conduit 5, communicating with a recycle pump‘ countercurrent flow within the vessel between the 6. The pump 6 discharges'through nozzles ‘I, recycled liquid discharged through the nozzles 28 which in turn discharge into the bottom of the and the recycled liquid introduced to the lower reaction vessel I. portion of the vessel by the pump 25. The feed hydrocarbons, together with recycled 30 In Fig. 3, fresh feed from line 39, recycle cat isoparaf?n, hydrocarbons, may be introduced to alyst from line 35, fresh catalyst from line 31, the suction side of the pump through a pipe 8. and catalyst-hydrocarbon mix from line 38 are In operation a stream of liquid mixture is mixed and forced by pump 36 through mixing continuously withdrawn from the lower portion nozzles 40 into reaction tube 4|, which discharges of the reaction“ vessel I through a pipe 9 con into the upper portion of secondary reaction taining a controlled ori?ce Ill. The pipe 9 com vessel 3|. A controlled proportion of reaction municates with the conduit 5 previously men products is continuously withdrawn from an in tioned, so that the liquid mixture withdrawn termediate point of vessel 3| by line 32 containing through the pipe 9 is conducted to the suction ori?ce 33. Pipe 32 preferably discharges from side of the pump 6 and there commingled with 40 vessel 3| at a point varying from about one fresh feed hydrocarbons and recycled isopara?in half to three-quarters of the height of the vessel. hydrocarbons prior to passage through the The withdrawn liquid is passed to a separator nozzles into the bottom of the vessel I. 34, by which means the hydrocarbons are sep The used catalyst withdrawn from the settler , arated from the used catalyst. The used catalyst, 3 is passed, all or in part, through a conduit all or in part, is returned by pipe 35 to the II, also communicating with the suction side of suction side of a recycling pump 36. the pump 6. Fresh catalyst, added as makeup, The suction side of the pump 36 also com may be introduced through a pipe l2, com municates through a pipe 38, with the bottom of municating with pipe ||, previously mentioned.‘ the reaction vessel 3|, thereby drawing off such The circulating stream of hydrocarbon and .1 O portion as may be desired of the liquid mixture catalyst passing through the pump 6 may contain accumulating in the bottom of the vessel. a ratio of catalyst to hydrocarbon of about 1:1 by volume. Where ,the catalyst is sulphuric acid the concentration is maintained in the range of about 90 to 100% H2804. The ratio of circulated hydrocarbon to fresh feed hydrocarbon is maintained high and may range between about 5:1 and 100:1, and pref erably between about 10:1 and 30: 1., The-ori?ces 4' and III are regulated so that the recycled hydrocarbon catalyst mixture pass ing through the pipe 9 is su?lcient to prevent The recycled hydrocarbons, feed hydrocarbons, and the recycled catalyst, together with makeup catalyst, etc., are brought into intimate contact by pump 36 and forced through nozzles 40,. as previously described, into tube 4|, which is a relatively long conduit of restricted cross sectional area, and therefore adapted to prolong the e?ect of agitation and turbulent ?ow as the ?uid discharged through the nozzles 40 rises therethrough. A ‘certain amount of settling is permitted in formation of a pool of separated catalyst in the the reaction vessel 3| so as to permit drawing lower portion of the'reactor; This, of course, off a stream rich in hydrocarbons through the depends upon a number of factors, including 65 pipe 32, while recycling through the pipe 38 a the efficiency of agitation, catalyst ratio, and mixture richer in catalyst. nature of catalyst. In general, the proportion While single stage operations have been illus withdrawn through pipe 9 is less than the over trated in the ‘drawing, it is contemplated that flow through pipe 2, and may comprise about, the methods of ?ow described may be used for 70 multiple stage operations and, in which case, the 5—75% of the latter. Fig. 2 likewise shows a reaction vessel 20 pro feed hydrocarbons may be introduced in part to vided with" an over?ow pipe 2| through which each stage or to as many of the stages as may the mixture of unreacted hydrocarbons, alkylate be desired. and catalyst accumulating in the top of the vessel Obviously many modi?cations and variations is vdrawn off. The pipe 2| is provided with a 76 of the invention, as hereinbefore set forth, may 2,413,105 tling zone where remaining catalyst is settled ' be made without departing from the spirit and from hydrocarbons. 4. The method according to claim 3, wherein scope thereof, and only such limitations should ‘ be imposed as are indicated in the appended claims. We claim: the catalyst is strong sulfuric acid of about 90 10()% strength. - 1. In the continuous alkylation of an isopara?in the said second zone comprises a chamber of with an ole?n in the presence of an immiscible enlarged cross-sectional area over the cross-sec alkylation catalyst of greater density than the hydrocarbons undergoing treatment, wherein the feed hydrocarbons are continuously introduced tional area of the said ?rst zone and into which chamber the stream of emulsion from theisaid ?rst zone enters at an upper portion thereof, and the stream of mixture richer in catalyst is with drawn from a lower portion of said chamber, into a closed circuit containing recirculating emulsion of mixed catalyst and hydrocarbons undergoing reaction and constituting an alkyla while‘ the stream of mixture richer in h’ifdrocar» tion reaction zone, and a portion of the recircu lating emulsion stream is continuously diverted to a separating zone where catalyst phase is set ' 5. The method according to claim 3, wherein - bons is withdrawn from an intermediate‘ portion 5 s-a I thereof. - ,_ , 6. The method according to claim 3, wherein the remaining catalyst settled from hydrocarbons are continuously discharged from the separating in said second settling zone is separated from the zone, and at least a portion of the eparated cata as rapidly and completely as pos lyst phase is recycled to the alk lation reaction 20 hydrocarbons‘ sible to thereby reduce to a minimum the time zone, the improvement which comprises removing ‘ of contact between catalyst and hydrocarbons the separated catalyst from the separating zone after separation from the emulsion. as rapidly and completely as possible to thereby tled from hydrocarbon phase and both phases reduce to a minimum the timeof contact between catalyst and hydrocarbon after separation from the emulsion. I 7. In the continuous alkylation of a low-boiling 25 isopara?in with an ole?n in the presence of an immiscible alkylation catalyst of greater density than the hydrocarbons undergoing treatment, the , 2. In the continuous alkylation of an isopara?in with an ole?n in the presence of strong sulfuric process which comprises continuously feeding the hydrocarbons into a ?owing emulsion stream of acid of about 90-100% strength, wherein the feed hydrocarbons are continuously introduced on the mixed catalyst and hydrocarbons undergoing reaction, passing the ?owing stream through a suction side of a recirculating pump into a ?ow restricted ?ow passage with turbulent ?ow under ing stream of emulsion of mixed acid and hydro alkylating conditions, then introducing the stream carbons undergoing reaction, the flowing stream into the upper portion of an enlarged secondary is forced with turbulent flow through a restricted reaction chamber providing relatively quiescent flow passage under alkylating conditions, and the 35 ?ow where additional reaction time is provided mixture then passes through an enlarged ?ow and partial settling of catalyst from hydrocar passage, from which a portion of the acid and hydrocarbons is returned to the suction side of ' bons occurs to form a‘ lower mixture richer in cat reduce to a minimum the time of contact between bons and passing said stream to a quiescent set- - alyst and an upper mixture richer in hydrocare the pump for recirculation through the system bons, continuously recycling from said enlarged 40 and a portion of the acid‘and hydrocarbons is chamber a stream of the mixture which has only diverted to a settling zone where acid is settled partially settled and which is richer in catalyst but from hydrocarbons, and'settled acid is withdrawn which has not formeda settled catalyst layer to-_ from said settling zone and at least a portion the said restricted ?ow passage to form the flowing‘ thereof is recycled to the recirculating emulsion ~ emulsion stream into which the feed hydrocarbons stream, the improvement which comprises remov 45 are introduced, and continuously diverting from ing the settled acid from the settling zone as an intermediate portion of said enlarged cham rapidly and as completely as possible to thereby ber a stream of the mixture richer in hydrocar acid and hydrocarbons after separation from the emulsion. 50 . tling zone where remaining catalyst separates 3. In the continuous alkylation of a low-boiling from the hydrocarbons. 8. In an alkylation process in'which an emul isopara?in with an ole?n in the presence of an sion of reactive hydrocarbons‘ and strong mineral -' ~ immiscible alkylation catalyst of greater density, acid is maintained and circulated in a circulatory system comprising a reaction zone and a primary ‘ than the hydrocarbons undergoing treatment, the process which comprises maintaining two zones 55 settling zone, the improved method which com of reaction in series, the ?rst of which comprises an initial zone of reaction‘ wherein feed hydro prises partially settling the emulsion entering said primary settling zone to form an upper layer of emulsion which is rich in hydrocarbons and a carbons are introduced into a ?owing stream of emulsion of mixed catalyst and hydrocarbons lower layer of emulsion'which is richer in acid, undergoing reaction and the mixture is agitated 60 recycling the said lower layer of emulsion to the under alkylating conditions, and the second of reaction zone before a settled acid layerv has which comprises a secondary relatively quiescent formed therefrom, separately withdrawing the reaction zone into which emulsion from the ?rst said upper layer of emulsion from the said pri-' , 'zone flows and wherein partial settling of the mary settling zone and diverting the same to a emulsion occurs forming a lower mixture richer 65 secondary settling zone wherein substantially in catalyst and an upper mixture richer in hydro ‘complete separation of acid from hydrocarbons is carbons, continuously recycling from the said effected; second zone a 'stream of the mixture which has only partially settled and which is richer in cata lyst but which has not formed a settled catalyst 70 , layer to the said ,?rst reaction zone to provide the said ?owing stream of emulsion therein, and continuously withdrawing from the said second zone a stream of the mixture richer'in hydro carbons and passing said stream to a second set- 75' 1 1 ‘ i 9. In the continuous alkylation of a low-boiling isopara?in with an ole?n in- the presence of an acid alkylation catalyst of greater density than the hydrocarbons undergoing, treatment, the proc ess which comprises maintaining two zones in se ries, the ?rst of which comprises anrinitial zone _ of reaction wherein feed hydrocarbons are intro a ‘ I - 7 2,413,105 duced into a ?owing stream of emulsion of mixed catalyst and hydrocarbons undergoing reaction and the mixture is agitated under alkylating con ditions, and the second of which comprises a, sec ondary reaction zone into which emulsion from 8 zones of agitated reaction, partial settling and more complete settling in series; continuously feeding the isoparaf?n and ole?n into the agitated reaction zone containing an emulsion of hydro carbons and alkylation catalyst under alkylating the ?rst zone flows and wherein partial settling conditions, passing emulsion from said reaction of the emulsion occurs, forming a lower emulsion zone to the partial settling zone where incomplete richer in catalyst and an upper emulsion richer settling of emulsion occurs, recycling partially but in hydrocarbons, continuously recycling a stream incompletely settled emulsion from one elevation of the emulsion richer in catalyst before the same 10 of said partial settling zone to said reaction zone has separated into a settled acid catalyst layer before the said emulsion has separated into a from the said second zone to the said initial re settled catalyst layer, passing additional emulsion action zone to provide the said ?owing stream of from a different and higher elevation of said par emulsion therein, and continuously withdrawing tial settling zone to said more complete settling from the said secondary'reaction zone a stream 15 zone where a separate hydrocarbon phase is of the emulsion richer in hydrocarbons and pass formed, and recovering alkylate from said hydro ing said stream to a settling zone where remain carbon phase. ing catalyst is settled from hydrocarbons. GEORGE B. HATCH. 10. Process for the continuous alkylation of an ERNEST F. PEVERE. isoparaiiin with an ole?n in the presence of al 20 LOUIS A. CLARKE. kylation catalyst which comprises maintaining FRANK H. BRUNER.