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Sept. 3, 1,946. _ |__ A.' CLARKE A_LKYLATION OFÁ HYDROCARBONS Filed Deo. 24, 1942 _.OE _. 2 Sheets-Sheet lA Sept '3, 1946» L. A. CLARKE _ 2,407,136 ALKYLATIOÑ OF HYDROCÀRBONS ` Filed Deo-L 24, 1942 HG2 2 Sheets-Sheet 2 FIG. 3 Louls A. CLARKE Rf. 2,407,136 l Patented Sept. 3, `1946 vUNITED STATES VPATENT OFFICE 2,407,136 ALKYLATION OF HYDROCARBONS `Louis A. Clarke, Fishkill, N. Y., assignor to The Texas Company, New York, N; Y., va corpora tion of Delaware # Application December 24, 1942, Serial No.'470,043 l 9 Claims. (Cl. BSO-683.4) 1 is the so-called mixer of the turbo type which utilizes internal recirculation of emulsion at very high velocity. The power requirements for this type of apparatus are substantial, and other objections and difficulties with certain types of This invention relates to alkylation for the production of motor >fuel hydrocarbons of high antiknock value, and more particularly to the alkylation of paraiiin hydrocarbons with olefms or other suitable alkylating agents in the pres ence of a liquid alkylation catalyst. catalysts, as noted above, are encountered. A third type of apparatus which has been used commercially for “this alkylation reaction is the so-called -jet reactor wherein the hydrocar bon and catalyst are pumped under high pressure One of the principal objects of the invention is to provide an improved method of carrying out this alkylation reaction to obtain large yields of high quality alkylate withgood catalyst life while avoiding emulsion and settling difficulties, elimi and introduced through a jet or thimble having a plurality of ports into the catalyst-hydrocarbon nating or minimizing corrosion difliculties and effecting economy in power consumption. Still another object of the invention is to pro mixture so as to produce substantial agitation and emulsiñcation of the contents of the reactor. In this form, emulsion is withdrawn through an vide novel and improved apparatus for carrying overflow, a minor portion being passed to' a suit able settler, and a major’ portion of the emulsion `being recycled to the jet.` This type of equipment simple in construction and of low initial and retains all the disadvantagesnoted above. maintenance cost. 'Other objects and advantages of the invention 20 The present invention provides a novel reactor which is generally applicable‘to the varioustypes will be Vapparent from the following description oi liquid alkylation catalysts. The expression when taken in conjunction with the accompany “liquid >alkylation catalyst” is used throughout ing drawings and appended claims. the Vdescription and claims tomean a material Heretofore, alkylation of an isoparafñn with an olefin has been carried out commercially in 25 which is fluid and pumpable even though it may contain dissolved or suspended solids or‘gases. several diiierent types of equipment> or reactors. This includes among others a pure liquid such as One generally used type is the so-called pump anhydrous hydrofluoric acid, a liquid containing and time tank reactor wherein the feed hydro out this alkylation reaction and accomplishing the above noted advantages, the apparatus being dissolved gas or other liquid such as hydrofluoric carbons are introduced at the suction side of a pump into an emulsion recycle stream of mixed 30 acid `containing 'dissolved boron iluoride, and `a liquid containing iinely divided suspended matter catalyst and hydrocarbon, the stream being forced but which is fluid and pumpable, such as alumi With turbulent flow through a suitable chiller num halide-hydrocarbon complex containing sus and then into a time tank which usually con pended aluminum halide. Moreover, by means tains suitable baiiies or other means for prevent ing breaking of the emulsion. A substantial prc- « of the novel method of this invention, emulsion and settling difficulties are avoided, corrosion and portion of the stream Withdrawn from the time erosion of parts, such as pumps and pump pack tank is recycled to the recirculating pump while ings, are effectively eliminated, and economy may a minor proportion is withdrawn for recovery of be effected in power consumption. In accordance with the present invention, the alkylate. ‘f While this type of equipment func tions very satisfactorily with certain catalysts, particularly sulfuric acid, difficulties are encoun liquid alkylation catalyst is maintained as a rel atively stationary body in the continuous phase tered When it is attempted to adapt that equip ment to a liquid catalyst containing suspended in a vertical reactor of substantial height, such as a tower, and a `mixed feed of paraffin hydro carbon and oleiin or other alkylating agent in solid material, such as an aluminum halide-hy drocarbon‘complex containing added aluminum halide, due to clogging of the lines and other liquid phase, with the paraflin in substantial molar excess of the alkylating agent, is intro duced through a small orifice or a plurality of orifices into the lower portion of the liquid cata-V causes, Moreover, the power requirements for operating the pump are material; and corrosion diiiiculties of the moving parts of the pump, the pump packing and other parts are experienced 50 lyst body. Asa matter of convenience, the in vention is described hereinafter in connection with certain-highly corrosive catalysts, such as with the use of olefin as the alkylating agent, but it is to be understood that other alkylating agents Another type of equipment which has` been hydrofluoricacid. ` - l usedcommercially for alkylation and operates -upon this generalprinciple of‘emulsion recycle can berused in place of the olefin, as more par 55 ticularly pointed out‘hereinbelow.' The mixed 2,407,136 3 feed passes through the oriiice or orifices in such a manner that the feed liquid is dispersed in fine drops in the continuous catalyst phase. The liquid alkylation catalyst has a higher speciiic gravity than the mixed paraiiin hydro carbon and olefin employed, whereby the dis persed drops of hydrocarbon mixture rise up wardly through the body of liquid catalyst due to this diiference in gravity. While there is some turbulence of the liquid catalyst body adjacent the point or points of introduction of the hydro carbon mixture, there is insuñicient agitation to form an emulsion. By the expression “emulsion” 4 lyst body, they coalesce to form a superposed hydrocarbon layer. A distinct interface between the liquid catalyst body and the superposed hy drocarbon layer is generally maintained in the upper portion of the tower. A stream of this hydrocarbon layer overñows through a discharge line in accordance with the feed rate to the tower. It is found with some catalysts that the dis persed hydrocarbon drops may tend to entrap a small amount of the catalyst liquid in this super posed hydrocarbon layer. Since the rate of rise of the dispersed drops of hydrocarbon through the catalyst is relatively slow, a considerable vol is meant the intimate mixture of subdivided par urne of dispersed hydrocarbon is normally pres ent at any one time in the catalyst liquid, so that the interface -level in the tower during operation character by mechanically driven stirrers, high is substantially above the initial level of the cata capacity pumps producing turbulent iiow, or agi lyst alone, Moreover, accidental or deliberate tating jets which produce eflìcient mixing and iiuctuations in the throughput may cause the movement of the catalyst along with the hydro 20 interface level to vary; and increase in through carbon through the reaction zone.v Such an emul put `may cause the level to reach the point of sion resists breaking in the reaction zone or re stream withdrawal. Further, the tower can be actor and is passed from the reactor into a rel satisfactorily operated with the interface level atively quiescent zone >of a settler, where sufficient at the stream withdrawal point so that the cata ticles of both catalyst and hydrocarbon hereto fore produced in alkylation reactions of this settling time is allowed for separate catalyst and 25 lyst continuously overflows along with hydro hydrocarbon phases to be formed. In the present carbon. In order to `insure that catalyst thus case, the hydrocarbon mix passes into the main tained body of catalyst liquid in the form of dis persed drops without emulsiiication. Even though into the neutralizing »and fractionating sections portion of the continuous catalyst phase due to the higher velocity of the hydrocarbon adjacent the locus of introduction, the liquid catalyst re erably at about the level thereof. Since such catalyst as is entrapped in the superposed hydro carried over with hydrocarbon does not pass of the unit, a separator or trap is provided ad there may bea localized disturbance of the lower 30 jacent the point of stream withdrawal and pref mains as ra continuous phase. The dispersed carbon layer or ‘overflows through the stream withdrawal is not in the form of an emulsion with -drops of hydrocarbon rise upwardly through the 35 the hydrocarbon, it immediately, or at least rap tower without rcorresponding upward movement idly, drops out in this separator, so that large of the catalyst liquid. The net result is 'that the .settling volume with substantial settling time is hydrocarbon mix passes in dispersed form up wardly through a relatively ‘stationary continuous catalyst phase, and promptly forms a separate and superposed hydrocarbon layer as it reaches the top or upper surface of the catalyst liquid. As distinguished from the prior practice in this art, wherein highly eñicient agitation with the formation of emulsion was considered a prime requisite for the production of vhigh yields of alkylate of good quality, it has now been 'dis covered that such emulsion-forming agitation can be avoided while 'still obtaining the desired results .by utilizing the principles of the present invention. .As :stated above, the liquid catalyst is relatively unagitated except for Vsuch turbulence and liquid ilow as results from the introduction of the reactants, and the movement of the dis persed drops of reactants upwardly through the maintained body of catalyst liquid. There is sub stantially*unidirectional flow -of the hydrocarbon or `reactant phase upwardly through the rela not required as in the case of an emulsion. How ever, the trap or separator can be constructed -of ' substantial volume, when hydrocarbon recycle is employed, to function as a reservoir for the cir culating hydrocarbon. All or any portion of this trapped-out catalyst is preferably returned to the maintained catalyst body within the tower, to gether with such make-up catalyst as may be re quired. In continuous operation, a portion of Athis catalyst may be intermittently or continu ously discharged from the system to recovery, and fresh catalyst introduced to make up for that withdrawn The recycle .of .settled hydrocarbon unmixed with acid or other catalyst to the alkylation re action zone has 'heretofore been proposed in con nection with reactors operating with eiilcient agi tation and th'e formation of emulsions. How ever, this requires very extensive settling volume, particularly where the recycle rate is many times the Vfresh feed rate. Consequently, such hydro tively stationary `continuous catalyst phase. Also, carbon recycle has not proved commercially at the orifice is of such small size, generally having a 60 tractive, and emulsion recycle has been univer `diameter of about ,de vinch to ‘lé inch, and is so sally employed. While a once-through operation correlated with the through-put, that the hydro. is feasible in the ‘present reactor, it is found that carbon Vreactants are dispersed in >the form of small drops of various sizes not ’exceed-ing about 1A; inch in diameter, and preferably' much smaller so as .t0 have a large .surf/ace area to volume ratio. This añords a :large Iarea vof contact between the outer ñlm of each Ydrop and the surrounding cata materially improved results can be .secured in many cases by recycling hydrocarbon to the reac tion Zone. Preferably a high recycle ratio of the order of about 10 to öll'volumes or more of hydro carbon recycle to 1 volume of fresh feed is em ployed. This materially increases the ratio of lyst liquid. This ‘operation has been found ‘to promote the desired alkylation reaction between the paraflin and the olelin present in the dispersed drops as the latter »pass upwardly through the substantial height of continuous catalyst phase. As the drops of Ymixed alkylate and unreac'ted paraffin `to olefin in the reaction zone and in creases the eifective time of contact, as is well known. Since the settling is quite rapid or a1 most instantaneous in the present-operation, it is hydrocarbon reach the upper surface of the cata- ” separated from an emulsion Aare effectively over' apparent that the diiiiculties inherent in previ ous proposalsl involving recycle of hydrocarbon 5 2,407,136 come. The recycled hydrocarbon is preferably first- admixed with the fresh feed hydrocarbon, mersV of isobutylene and normal butylene, mixed or non-selective Ca-C4 polymers, and the like, and various fractions of thermally or catalyti cally cracked gasolines and of polymer naph and themixture introduced through' the orifice or oriñces into the reaction zone. The trapped out catalyst is preferably returned directly and thas may be used. by gravity to the maintained catalyst body, there by avoiding the use of pumps in the handling of the more corrosive catalyst liquid. If desired, the reactor or tower of the present invention may be supplied in the reaction zone 10 with one or more layers of solid contact or filling In place of an olefin as-the alkylating agent, various alcohols and ethers, such as isopropyl alcohol, tertiary butyl alcohol, secondary butyl alcohol, isopropyl ether and the like, may be em ployed with suitable known alkylation catalysts which' have tolerance for water liberated in the material to thereby increase the length of the reaction. Likewise, the corresponding alkyl path of flow and th'e time of contact for each esters, such as the alkyl halides, sulfates, phos once-through flow- of the dispersed drops in the phates, etc. of the oleñns, may be used as the catalyst liquid. The packed tower can be oper alkylating agent with an appropriate or compat ated withonce-through flow or hydrocarbon re ible alkylation catalyst, as- is well known. cycle. Any suitable contact material, which is vWherever the expression “alkylating agent” is non-reactive with respect to the catalyst and the used throughout the description and claims, it reactants and which provides sufficient free space will be understood that this refers to oleñns as ‘for the proper travel of the drops, may be em 20 well as alcohols, ethers and esters of th‘e charac ployed. A very suitable type of material for ter described above and which are capable of re this purpose consists of‘small contact pieces, each acting with a paraflin or other hydrocarbon hav shaped to simulate a saddle, and known to the ing a replaceable hydrogen atom to produce an trade as “berl saddles”. There is some indica alkylated hydrocarbon of higher molecular weight tion that the use of a packing in the tower may of the character set forth herein. ` ` enable the use of somewhat larger size drops Any ofthe well known conditions suitable for and obtain as good results as with a higher degree the various alkylation reactions can be used. In of dispersion (i. e., smaller size drops) in an un general, a substantial molar excess of paraffin to olefin or other alkylating agent is employed, 4packed tower. Moreover, the combination of a packed tower with a high degree of dispersion such as a `feed ratio in excess of 1:1 and prefer can be used. i However, very satisfactory results ably about 4:1 to 8:1, which provides a sub Vare secured with an unpacked tower operating stantially higher contact ratio in the reaction with either Yonce-through' flow or hydrocarbon recycle, preferably the latter. Any of the conventional catalytic alkylation 35 zone generally inl excess of about 50:1 when hy drocarbon recycle is used. The reactor is main -reactions can be carried out by the method and tained under sufficient pressure to linsure- that the hydrocarbons and alkylating agents are in with the apparatus of ` the present invention. the liquid phase. The temperature of the reac-V Thus, the reaction of an isop'araf’fin with an ole .ñn or other alkylating agent, as well as the alkyl ation of a normal parafûn with an olefin or other 'alkylating agent, in ’the presence of suitable alkylation catalysts can be accomplished. Th'e 'paraffin charge stock may be either normally gaseous or normally liquid or a mixture thereof. In isoparafiin alkylation, isobutane and isopen tane are preferred, although it is to be under `stood that any of the low boiling isoparañins may be used and conventional catalysts effective for such isoparaiiin alkylation can be employed.` The present invention appears particularly effec- f tion varies with the hydrocarbons or alkylating agents employed and with the catalyst, as is well understood, but generally ranges from about _40° F. to about 150° F. A high ratio of catalyst to hydrocarbon is inherently maintained in the reaction zone due to the maintained body of cat alyst liquid of substantial height through which the» hydrocarbon phase is dispersed. As pointed out above, the present invention departs radically -from the previous practice in this art with respect to agitation, since mechanical stirrers and high capacity pumps with eincient agitation are avoid ed, and introduction of dispersed hydrocarbon vtive for isoparañîin alkylation with hydroiiuoric acid or aluminum chloride-hydrocarbon complex `without the formation of an emulsion and the `containing suspended aluminum chloride as the catalyst. Likewise normal paraflins can be alkyl ated with olei'lns or other alkylating agents in the Vpresence of suitable catalysts, such' as hy tively stationary body of continuous catalystV drogen ñuoride containing dissolved boron tri iiuoride or aluminum chloride-hydrocarbon com plex' containing suspended aluminum chloride. Various normally gaseous or liquid normal paraf-` ñns, such as normal butane, normal pentane and -higher normal paraffins or mixtures thereof, may be used for the charge stock. Likewise, mixtures of visoparaffìns and normal paraffins may be em ployed. 'I'he features of tower type alkylation of the present character, as applied to isobutane ethylene with an activated aluminum chloride hydrocarbon complex catalyst, is disclosed land claimed in the copending application of Louis A. Clarke, Serial N0. 535,261, flled May 12, 1944. The olefin charge stock may be any of the normally gaseous or normally liquid olefins or mixtures thereof. For‘example, ethylene, pro pylene, butylenes, amylenes, C4 polymersI such Vas di-isobutylene and tri-isobutylene, cross poly- l risingof hydrocarbon drops through the» rela ' phase by the difference in gravity therebetween, »are substituted.A ‘ ‘ ` The invention is more particularly illustrated in the attached drawings which disclose preferred embodiments thereof. In the drawings: Fig. 1 is a diagrammatic illustration of appa 'ratus’ suitable for carrying out the method of the present invention; Fig. 2 is a partial vertical sectional view on an enlarged scale of the tower reactor of Fig. l. Fig. 3 is a partial view similar to Fig. 2 of a modification; " Fig. 4 is a plan view of the orifice plate of Fig. 3; and ‘ Fig. 5 is a partial View similar to Fig. 2 of a second modification. Referring to the drawings, particularly Fig. 1, the hydrocarbon mix 'containing the paraffin and ' olefin in liquid phase is introduced by pump 9 through pipe I0 controlled by valve Il into the bottom of tower `I2 beneath the orifice plate I3. .The `tower may be equipped with an external 2,407,136 8 jacket I5 provided with inlet IB and outlet I1 for the supply of a suitable cooling or heating medium to maintain the desired temperature within the reaction zone. It is to be understood that other conventional means for controlling the temperature in the reaction zone can be used, mentioned condition of operation, which is ob jectionable and is to be avoided, can be readily detected by the drop in interface level. While satisfactory operation can be secured at the lower throughputs described above, it is generally de sirable to operate in. the upper portion of the such as the fresh feed and recycle hydrocarbon chiller hereinafter described, internal evapora tive cooling, etc. As shown more particularly in Fig. 2, the tower is partially filled with a suit throughput range which produces greater disper sion and a higher interface level approaching the upper limit described above. Referring again to Fig. 1, the tower I2 is able liquid catalyst I8. The amount of catalyst liquid is generally such that,l during operation equipped with an overflow or outlet 26 through which the hydrocarbon layer 20 is discharged in with an appreciable volume of hydrocarbon liq uid dispersed` in the Catalyst at any one time, the interface I9 between the relatively stationary a stream to a suitable separator or trap 21. AS shown, this is preferably a cylindrical vessel arranged with its longitudinal axis somewhat in clined to the horizontal. Adjacent the lower end body of liquid catalyst and the superposed hydro of the separator, a bottom discharge line 28 carbon layer 20 is positioned adjacent the upper is provided to conduct catalyst by gravity back end ofthe tower. to the lower portion of the tower. Pipe 28 opens The oriñce plate I3 is provided with an open ing or orifice 22 shown as positioned at the ver 20 into the tower at a locus 29 opposite the main tained catalyst body I8, so that this catalyst is tical axis of the tower, this orifice being of small returned directly thereto. size of the order previously indicated. The en The upper end of separator 21' is also provided tire tower is maintained under sufficient pressure with an overflow 33 connected with branched so that the hydrocarbon mix ysupplied by line I0 is in liquid phase, and this mix is under sufi-l 25 lines 3l and 32 controlled -by valves 3|’ and 32’ respectively. Hydrocarbon may be passed to the cient additional pressure to counter-balance the alkylate discharge line 3| or a portion of the height of the liquid column within the tower and alkylate passed to the discharge line 3| and the to overcome the pressure drop through orifice 22 balance to the hydrocarbon recycle line 32 con to obtain the desired dispersion. The space 23 in the tower beneath the orifice plate I3 remains 30 taining a suitable pum-p 33. Line 32 communi Cates with the hydrocarbon mix feed lineV I0, a filled with the hydrocarbon mix, and the catalyst suitable surge drum 34 being preferably con liquid is prevented from flowing down through nected to line 32 by branch line 34' in advance of the orifice. into this space and backing up into pipe Ill to take care of fiuctuations in the pump the- inlet pipe I0 by the maintained feed pres sure. This causes the hydrocarbon to pass 35 ing rate and to maintain the regulated pressure in the feed line Ill. Preferably, a'suitable chiller through orifice 22 with the formation of a mul or heat exchanger 35 is positioned within line titude of small drops indicated at 24, which pass Iii' in advance of the tower inlet to- precondition up through the liquid catalyst body due to the the temperature of the fresh feed hydrocarbon difference in gravity between the catalyst and the hydrocarbon. As the drops reach the interface 40 and the recycle hydrocarbon to maintain the desired temperature withinv the reaction zone of I9, they coalesce to form the superposed hydro the tower. Any suitable control means can be carbon layer 20. used for regulating the pressure and rate of While the orifice plate i3 can be equipped with through-put of the fresh feed and hydrocarbon a simple opening in some cases, it is preferably recycle through the orifice to thereby control and provided with an upstanding nozzle 25 of a known regulate the degree of dispersion of the drops type adapted to effect a spray dispersion of the in the catalyst liquid, such as the proportion hydrocarbon in the form of ñne drops. For any ing pumps 9 and 33 and the surge tank 34 as given nozzle of this character, at the lower shown. throughput or rate of supply of hydrocarbon, As pointed out above, a major portion of the fewer drops of a larger size will issue from the hydrocarbon is preferably recycled through line opening or discharge orifice of the nozzle. Theo >3? and> re-introduced together with the fresh retically, the throughput rate can be reduced to feed through line I0 into the tower. A minor proportion of the settled hydrocarbon is with drawn in accordance with the fresh feed rate through pipe 3| and passed by pump 36 together drop is of a proper small size. As the through with suitable neutralizing agent, such as caustic put rate is increased from this given orifice, the drops not only issue faster but are of smaller soda solution, introduced by line 31, into a scrub ber 33 where the hydrocarbon is neutralized. size. This also causes the level of the inter face I9 to rise, due to the larger number of dis 60 The neutralized materiall overñows by line 39 persed drops and the greater volume of hydro into an intermediate portion of a settler 49 where carbon present in the liquid catalyst body at any the caustic soda solution settles out and is with drawn through line 4I. The bulk of the solu one time. As the throughput is further in tion is recycled by line 42 to line 31 for reuse creased, the drops become exceedingly fine and in treating fresh quantities of hydrocarbon, while the interface level reaches a maximum height. a minor proportion may be withdrawn inter Further increase of the throughput beyond this mittently or continuously by a discharge line limit causes an accumulation of hydrocarbon to 43, fresh make-up caustic soda solution being be formed within the base of the tower surround added by feed line 44. ing the nozzle, from which globs o-f the hydro The neutralized and settled hydrocarbon over carbon break off and rise upwardly through the flows from settler 4I] through line 43 and is in tower. This latter condition results in a drop troduced by pump 41 into a stabilizer 48 where in the interface level, due to the fact that the unreacted gases including excess paraffin are degree of dispersion and the quantity of hydro removed overhead by line 49. These lighter carbon dispersed in the catalyst liquid at any one time is then reduced. Consequently, this last 75 gases are forced by pump 50 into a suitable frac the point where the drops issue one after the other in relatively slow succession, provided the orifice is sufficiently small so that each individual 2,497,136 10-Y 9 .. tionator 5I where separation is made between unreacted isoparaiiin, such as isobutane, which is withdrawn by overhead line 52 for recycling to the reaction tower I2, and any heavier hydro carbons such as normal butane, which are with drawn by bottom line 53. It will be understood that >the fractionating system shown is that par ticularly designed for isobutane alkylation spaced as to-substantially encompass` the cross section of the tower‘with the drops. This_ pro wherein the charge, which may be a suitable thetower 86 is provided with a packing 8l of solid refinery C4 cut, also contains normal butane. However, the fractionating system can modi While a nozzle or plurality of nozzles can be'used . ned from that 4shown in accordance with the charge stock being handled as is well understood lysts such as an aluminum chloride-hydrocarbon in the art. ' duces a series of sprays of drops 'l5 into the lower , portion of the maintained liquid catalyst body, while avoiding undueagitation, and avoiding un due interference of the drops from one nozzle with those from another.' ` Figure 5 dis closes another modification wherein ' Contact material above .. the orifice plate 82. , in this form, it is foundthat with certain cata complex containing suspended aluminum chlo-` . ride a simple opening or oriñce 83 through lthe The stabilized alkylate is removed from the bottom of stabilizer 48 byline 55-and passed by orifice plate functions satisfactorily to accom by bottom discharge line 58‘. of the contact zone containing the liquid catalyst, or may extend above .the oriñce plate 82 through out only a portion of the height of the tower confining the catalyst, with an upper unpackedv plish the desired dispersion and distribution of pump 56 to a> suitab-le fractionator 51 which the hydrocarbon drops throughout the catalyst serves to take overhead a desired fraction, such liquid, as aided by the contact material. This as an aviation fraction boiling up to about 350 to 375° F. A heavier residue fraction is removed 20 packing may extend throughout substantially all The o-verhead vaporized fraction passes by line 59 through a suitable condenser 60, and the condensed liquid flows by line 6I into an accumulator 62. Any light gases may :be bled off from accumulator 25 section "84. > As shown, the hydrocarbon issuing from oriñce 83 in the form of the dispersed drops 62 by vapor drawoff 63 and the desired stabilized 85 is distributed within a short upward travel fraction of the alkylate is removed by bottom throughout the cross~section of the tower. The line 64 to suitable blending tanks or storage (not shown). Y yThe `reaction tower |'2 illustrated in Fig. 2 is of a relatively smaller capacity type having a single orifice 22. This tower may be conven dispersed drops rise through the catalyst liquid Vthrough the free space provided by the packing, ‘the latter impeding the normal velocity of up ward travel due to 4difference in gravity and in- ' creasing the length of the path of travel thereof. iently constructed of an interior diameter of While a nozzle, or a plurality of nozzles, adapt about one inchto 12 inches or more, with an ori ‘ rice selected to give fine dispersion and a lateral 35. ed to direct the drops upwardly within the tower, distribution to substantially extend throughout> ‘ has been shown in the drawings, it is to be under stood that this arrangement is not essential. the, >cross-section thereof. The tower may be Thus, the nozzle may be directed in an inclined from about 5 feet to 20 feet or more in height.` or horizontal direction, so long as the hydrocar It. will ‘be understood that this is merely repre sentative of satisfactory tower reactors having a 40 bon is dispersed into the catalyst liquid in the " form of fine drops as described above, which are single orifice, and that the invention is not lim then free to rise through the catalyst liquid, and ited to -towers of these dimensions. However, so long as undue agitation and emulsification are for a single oriñce type, the height should be avoided. Moreover, it is to be understood that many times greater than the diameter. Such towers have >,been successfully operated -with 45 other types of dispersing devices can be employed, such as a cone adapted to introduce the hydro heights of catalyst liquid varying from about 30 carbon from the periphery thereof and thus dis inches up to> about 200 inches or more. ' seminate the drops over a larger area of the Where a plural number of oriiices are used, cross-section of the tower. ` the diameter >of the >tower maybe greatly in The invention is further illustrated by the fol creased without necessarily increasing the height.- lowing specific examples; but it is to be under stood that these are given by way of explanation and the invention is not limitedthereto. Ercample I The latter dimension is regulated in accordance with thecharge stocks and catalysts with a view to insuring substantially complete disappearance of the oleñn or other alkylating agent as such in a once-through passage. objectionable side’ 55 The Afollowing example illustrates the applica? reactions due to prolonged contact of hydrocar tion of the invention to the alkylation of a mixbon or unreacted olefin with catalyst »in transfer ture of isobutane with a C4 fraction from a crack linesA and settlers are minimized or avoided. »It ing operation, using anhydrous HF as the cata is to be understood that two or more towers'canä lyst. The mixed hydrocarbon charge had the be used with series flow of hydrocarbon there 60 following analysis: through, where the desired degree of conversion ‘ or `reaction cannot be accomplished in a single tower of practical height. In this tower reactor, - v ` i» In Figures 3 and 4, there is shown a modifica-v tion of the tower reactor particularly designed for largerscale operation. In this form the tower» 10 is of relatively larger'diameter, such as from Weight percent 1.4 Isobutane _____________________________ __ 68.6 the time of >contact for all portions of the react# ing hydrocarbons is uniform. ‘ Propane ______________________________ __ 65 Normal butane- ________________________ __ 14.7~ y Isobutylene __ _________ _;__; ____________ _- 6.9> Normal butylenes ______________________ __ 8.0 Caïn. ________________________________ _.; 0,4 The apparatus employed in the following runs A bottom oriñce plateV 12 70 included a `.tower constructed of one-inch steel tubing about seven feet .long equipped with a is ’provided with a plurality of upstanding nozzles jacket through which cooling water was passed 1-3 arranged more or less uniformly over the cross two to six feet or more. section'of the plate. „ Eaohnozzle is constructed for thepurpose of controlling the temperature. The overflow from the tower was connected with to provide effective dispersionin the manner pre viQuÍSly, . descrieéd; 'the Several mzzl@ .heini S0.' 75 aninclined separator made of copper which was 1l 12 two inches in diameter by seven feet long. The towerwas operated under two conditions, namely, packed for about iive feet of its height with brass’ apparatus of the present invention avoided hy drogen transfer reaction with the production of n-butane in the above noted- C4 alkylation with HF. An analysis ofthe oífgas from the run with the unpacked tower listed above showedl the fol-> plated steel jack chain and utilizing once through operation for one continuous run, and unpacked with top separator recycle for a second lowing: continuous run. The volumetric characteristics of the tower were as follows: , Weight per cent Propane cc. Isobutane 1.3 _____________________________ __ '75.7' Volume of tower unpacked _____________ __ 1340 10 Normal butane _________________________ __ 21.6 Free space in tower packed...v __________ __ 1050 Residue _______________________________ __ 1.4 Free space in tower to top of‘ packing ____ __ 675 Calculating from the charge stocky employed The tower was provided with an axially-arranged and assuming no hydrogen transfer reaction„ the theoretical 'weight percentage of normal- butane in the oiigas should be 21.5%. It is; thusI seen that alkylation took place in the- presence of HF under these conditions without this objectionable side reaction, thereby avoiding the formation of un desired normal butane. orifice et; inch in diameter. In the run with the packed tower, the latter Was charged with 605 grams (605 cc.) of anhy drous liquid HF which nearlyl filled the packed portion thereof. The remainder of the system was then ñlled with isobutane, and the premixed charge, composed of a primary debutanizer over head and commercial isobutane which had the above listed analysis, was charged into the bot tom of the maintained catalyst body through the oriñce ata charge rate varying from 0.4 to 1.6 pounds per hour. The hydrocarbon mixture Example II The following runs illustrate the alkylation of a normal parañ‘ln, such as normal butane, with ' » an oleñn in the presence of a catalyst containing a major proportion by weight of anhydrous liq passed upwardly through the packed catalyst uid HF and a minor proportion of BF: dissolved layer, and a stream of the superposed hydrocar therein, under the general conditions set forth bon layer was continuously Withdrawn to the sep in the copending application of Louis A. Clarke, arator, from which a top eiiiuent hydrocarbon stream was passed through a caustic scrubber, 510i Serial NO. 438,418, filed April 10, 1942. Briefly, these conditions include a high normal parafñn stabilized, distilled and tested. to-oleñn mol ratio, a catalyst consisting of HFv Inthe run withY the unpacked tower employ containing less than 46% by weight of BF: based ingï top separator recycle, the tower was- charged on the weight of the mixed catalyst and gener with 415 grams (415 cc.) of the anhydrous liquid ' 'rally about 12-20%, a temperature within the HF and' the free space iilled with isobutane. Hy range of 0-l50° F. with about 'l0-130° F. being drocarbon fresh feed of the' same composition preferred, a pressure of about 100-250 pounds per together with hydrocarbon recycle from the top square inch, and a high catalyst to hydrocarbon of the settler were passed through the oriiice into ratio in the reaction zone. AS set forth in the the catalyst body, the fresh feed charge rate being 0.4 pound per hour and the recycle rate being 1.7 40 said copending application noted immediately above, this. reaction not only eiTects alkylation of gallons perV hour. A stream from the hydrocar normal paraffin with oleñn but concomitantly ef bon layer in the tower was passed to the sepa~ fects isomerization or the production of a sub rator, from which a major portion of the hydro stantial yield of isobutane. carbon >was recycled to the fresh feed inlet while A series of continuous runs utilizing the HF the remainder ywas passed through a caustic BFs catalyst for the alkylation of normal butane scrubber, stabilized, distilled and tested. with various oleñns to produce alkylate and con Each of the runs was continued vfor a period comitantly form isobutane were carried out in in excess of about 50 hours. The conditions and accordance with the present invention in a stain results of thel runs were as follows: 50 less steel unpacked tower eight feet high and one inch inside diameter. The catalyst is highly Packed ~ Unpacked corrosive to iron and ordinary steel; but copper, tower tower-top Monel metalv and I8-8 stainless steel satisfac single separator pass recycle torily resist corrosion. A convenient method of maintaining the required amount of BFs in the Charge rate, pounds per hour ____ ._ _. 0. 4-1. 6 0.4 catalyst liquid, which was used in these runs, in-Recycle rate, gallons per hou _ i None 1. 7 volves Isaturating normal butane at room tem Temperature, ° F ......... ._ 70 70 perature and about 160 pounds per square inch Isobutane/oleiin mol ratio 5:1 ' 5:1 Yield debutanized alkylate: i pressure with BFS; and introducing this normal Weight per cent on olefin ........... .i _184 182 Volume per cent 311° F. E. P. frac butane saturated with BFa. together with a stream tion on basis of total debutanized of mixed normal butane and oleíin through the alkylate ........................... _. 77 90 , Volume per cent 2,2,4 trimethylpen orifice at the bottom of the tower into the. pre tane on basis of total debutanized < alkylate ___________________________ __ 20 viously supplied catalyst liquid. 'I‘he tower was 48» provided with a 1/8" diameter orifice. A brass tube two inches in diameter and seven feet long 65 served as a separator.y Octanenumber of 311° F. E. nalkyme Clear ____________________ ._ ' AFD 1C 90.6 _____________ ._ In starting up the` run, the system was ñlled to CFRM 200- pounds pressure with catalyst and. normal butane. Various heights of the maintained body 94.6. of catalyst were employed in different. runs -, but in the runs listed below, a height of about 108 109’ ’ was used with very satisfactory results. Topv separator recycle was employed, and catalyst was Plus l ce. TEL/ga1lon__... 97.1 ............. ._ Ist’ìIÄlëzItJane-l-l-.ZG cc. Plus 3 cc. TEL/gallon_-_.. Iso - octane + 0.14 cc. TEL. Plus 6 cc. TEL/gallon _______________________ __ Iso-octauc-|`-l_98 cc. TEL. f ' It was found in this work that the method and 75 returned to the tower by gravity flow. The por tion of the hydrocarbon 'not recycled was caustic neutralized, stabilized, fractionated and tested. - 25,407,136@1 13T ethylene respectively: y Y ‘ 114i catalystliquid may be continuously or intermit "I'he‘ following are the conditions and results on two continuous runs of extended duration on normal butane-propylene and normal butane tently withdrawn from a lowerV` or intermediate portion of the tower, and fresh catalyst liquid supplied to the maintained catalyst body con-` . tinuously or intermittently at an upper or inter-` Olefin 109 70 0. 8 23. 3 7. 9 Bromine number _ _ _ _ _ _ _ _ _ _ 108 70 0. 8 23. 3 _10. 5 257 394 95. _6 96. 1 _ _ _ _ _ _ Residuerper cent by volume of total alk ate_ 4. 4 _ 12. 2+ stantially higher velocity than the velocity of movement of the catalyst. In such event, the dis persed hydrocarbon drops are still appropriately described as rising upwardly through a “relatively stationary” body of the catalyst liquid, and this 3. 9 ' expression is used as a matter of convenience 2 throughout the description and claims to include 0r Bromine number _________________ ..-_____ i __________ __ Volumes’of alkylate per volume of catalyst. hydrocarbon, the latter of course moving at a sub 83. 9 0 Octane number CFRM _________ ._` _-_` ___________ __ Isobutane: mediate portion of the tower. Thus, there may be relatively slow and progressive movement of the catalyst liquid downwardly through the tower countercurrent to the upwardly rising drops of. Propylene Ethylene _ 29. 2+’ these various operations as above described. . Weight per cent yield basis normalbu~ tane..v ...... __ __________________ __’__-._ 27.1 Weight per cent yield basis olefin _ _ _`. _ _ _ 29 Weight per cent yield basis catalyslr.-. 974 It is therefore seen that, in accordance with 40. 4 420 l, 958 20 ` In the, series of runs mentioned above, it was found _that by increasing the height of the cata lyst from 31’ ’ to 109’ ’ in normal butane-propylene alkylation employing hydrocarbon recycle, there was an increase in the yield off alkylate basis the present invention, the necessity for handling` and recycling catalyst, oran emulsion contain ing catalyst, by high capacity pumps or other moving parts is avoided. The recycle of hydro carbonvunmixed with catalyst can be accom-_ vplislied without corrosion or erosion difficulties. ' The tower itself and other parts such as the sep arator and lines which contact the catalyst can olefin, the percent of alkylate boiling below 311° readily be constructed of corrosion-resistant ma F., the 4conversion of normal butane to isobu-tane terial; and the `more highly corrosive catalystY and the catalyst life. Also, byV increasing the ratio does not come in contact with movingv parts,` of top settler recycle to fresh feed from `11.7 to 30' pump packings and the like. _ y . 23.3, the yields and catalyst life were improved. It has heretofore been proposed to effect ab, Higher yields of alkylate and isobutane base-d on sorption or polymerization of oleñns by dispers the olefin charged were obtained from normal ing the oleíins >in liquid phase through nozzles butano-ethylene _alkylation than from normal 35 into aA body of sulfuric acid. However, it is well butane-propylene alkylation. __ _ . q ‘ recognized that such reactions take place read _ While the invention has been described above ily without efficient agitation. It has also been in connection with the alkylation of paraffins with proposed to apply this operation to a refinery C4 olefins or other lalkylating agents, it is alsocon cut from which isobutylene had been removed, templated that Vthe method and apparatus of the and which contained both isobutane and n-bu--. present invention can be employed for thealkyla tylenes with the latter in molar excess, in the tion of other hydrocarbons having afreplac'eable presence of strong H2SO4 of at least 87%, for the hydrogen atom, such as aromatic and naphthene absorption of n-butylenes in the acid and the hydrocarbons, with olefins or other alkylating concomitant production of a small yield of gas agents, 4such as alcohols’ethers and esters. For _ oline hydrocarbons of an unsaturated character. example, the alkylation of benzene with propylene It has not been heretofore recognized and taught for the production of isopropyl benzene, the-al kylation of benzene with ethylene for the produc tion of ethyl benzene, _etc.,in the presence oflsuit ì that, in accordance with the method of the pres-Í ent invention, and by avoiding eiiicient agitation producing an emulsion, alkylation of a hydro able well known liquid catalysts which are im 50 carbon or paraflin with an olefin or other alkylat miscible with >the hydrocarbon reactants, can be ing agent could be accomplished as the principal carried ,out in the manner and with the> tower reaction of the process, with minimum oleñn ab sorption and/or polymerization, whereby a sub `While in certain cases, the same liquid cata stantially saturated alkylate of good quality is'ob lyst body as originally supplied tothe tower may tained with minimum catalyst deterioration and be maintained _therein for the entire reaction, thus resultant long catalyst life. This was unexpected providing continuous feed of hydrocarbon with and directly contrary to the previous knowledge batch feed of catalyst, it is to be understood that and experience in »this alkylation art. As pointed a portion of the liquid catalyst may be continu out above, this invention is particularly advanta ously or intermittently withdrawn and replaced geous for those alkylation catalysts which are with fresh catalyst during continuance of the 60 morecorrosive to pump parts and packings than process. . By the expression “relatively stationary” sulfuric acid, such as I-IF, vlilik-Bib., BFanI-IZO, as applied tov the'liqui‘d catalyst body, it will be etc., as well as for those alkylation catalysts which apparent that this signifies that the hydrocarbon tend to clog emulsion recycle lines, such as the moves relatively to the catalyst body and at a 65 aluminum chloride-hydrocarbon complex con reactor vas described above. _ Y ` _ substantially greater rate or velocity, irrespective of such localized movement or turbulence which taining suspended aluminum chloride. Obviously many modiñcations and variations of the invention. as hereinbefore set forth, may be made Without departing from the spirit and be understood that this expression includes op scope thereof, and therefore only such limitations erations in which a small portion of the catalyst 70 should be imposed as are indicated in the ap liquid may continuously or intermittently over pended claims. flow to the separator and be returned through I claim: f ‘ . the gravity line or in other suitable manner to 1. The method of continuously alkylating a the liquid catalyst confined within the tower, as Well as an operation in which a portion of the 75 hydrocarbon having a replaceable hydrogen at may exist within the catalyst liquid, particularly at the lower portion thereof. Moreover, itis to 15` 2,407,136 om with an alkylating agent in the presence of an alkylation catalyst of greater specific gravity than the hydrocarbon and alkylating agent, which comprises maintaining an undispersedl liquid body ofv the alkylation catalyst of substantial» height as the continuous phase in a reaction 16 5.> The method according to claim 1, wherein at least a portion of the settled catalyst is re turned directly to the maintained catalyst body without previous mixing with the fresh feed and recycled hydrocarbon dispersed into the lower portion of the catalyst body. 6. The method according to claim 1, wherein the hydrocarbon is a paraiiin, and the alkylating zone, continuously dispersing a fresh feed> of mixed hydrocarbon and alkylating agent sub stantially free from alkylation catalyst and with agent is an oleñn. the hydrocarbon in liquid phase i-nto a lower por-V 10 '7. The method according to claim 1,. wherein: tion of the liquid catalyst body Without dispersion the movement of the dispersed liquid> drops ris of the latter to form-a multitude of ñne liquid ing through the liquid catalyst body in the reac drops of mixed hydrocarbon and alkylating agent tion zone is modified and increased in length by which rise in dispersed form through a substan contact with packing material submerged within tial height of the continuous catalyst phase- due the liquid catalyst body. tol difference in gravity therebetween, whereby 8. The method of continuously alkylating a alkylation of the hydrocarbon with the alkylat» hydrocarbon having a replaceable hydrogen atom ing agent> to form normal-ly liquid alkylate takes with an alkylating agent in the presence of an place as the principal reaction of the process, the `alkylation catalyst of greater specific gravity than dispersed drops coalescing to form a hydrocar-v 20 the hydrocarbon and alkylatingv agent, which bon phase upon reaching the upper surface of' comprises maintaining an undispersed liquid body the liquid catalyst body, continuously removing of the alkylation catalyst of substantial height a stream containing the coalesced hydrocarbon as the continuous phase in a reaction zone, con phase, settling any entrained catalyst from thev tinuously dispersing a fresh feed of> mixed- hy removed stream to provide a hydrocarbon layer substantially free from catalyst, recycling a ma drocarbon and alkylating agent substantially free from alkylation catalyst and with the hydrocar jor portion of the hydrocarbon layer containing bon in liquid phase into a lower portion of the alkylate and substantially free from catalyst and liquid catalyst body without dispersion of the mixing the same with the fresh feed for redis latter to form a multitude of ñne liquid drops persion unmixed with alkylation catalyst into 30 ofi mixed hydrocarbon and alkylating agent which the lower portion of the catalyst body, recovering rise in dispersed form through a substantial a substantially saturated hydrocarbon alkylate height of the continuous catalyst phase due to from- a minor portion of said hydrocarbon layer, difference in gravity therebetween, whereby al and adding _fresh alkylation catalyst directly to kylation of the hydrocarbon with the alkylating the maintained body without premixing with said 35 agent to form normally liquid> alkylate takes place fresh feed as the operation proceeds to preserve the alkylating- activity thereof. 2. The method according to claim 1-J wherein the said hydrocarbon is a low-boiling isoparail‘in as the principa1 reaction of the process, the dis persed drops coalescingV to form a hydrocarbon phase upon reaching the upper surface of the liquid catalyst body, continuously removing from and the alkylating agent is- an olefin, and the» 40 substantially at the level of the interface be liquid catalyst comprises hydroiluoric acid. tween the upper surface of the continuous cata 3. The method according to claim l, wherein the said hydrocarbon is a normal parañìn and lyst body and the lower surface of the coalesced hydrocarbon phase a stream containing coalesced the al-kylating agent is an olefin, and the liquid hydrocarbons along with some overflow catalyst catalyst consists essentially of a major propor 45 liquid, rapidly separating catalyst liquid from the tion of- substantially- anhydrous hydrofluoric acid removed stream to provide a hydrocarbon layer containing a minor proportion of boron fluoride. substantially free from catalyst, removing a 4. The method according tov claim l, whereinl stream of the hydrocarbon layer and recovering the rate of throughput of fresh feed and. recycled a substantially saturated hydrocarbon alkylate hydrocarbon produces- a dispersion of a large 50 therefrom, and adding alkyl'ation catalyst direct number of drops- each of less tha-n 1A; inch in ly to the.- maintained catalyst body without pre diameter throughout the liquid* catalyst body giv ing the the tial mixing with said fresh feed as the operation pro a substantial rise in the operating levelY of ceeds to maintain the volume and alkylating ac interface between the catalyst liquidi and tivity of the said catalyst body. superposed hydrocarbon layer above the ini 55 9. The method according to claim 8, wherein level of the catalyst body alone, the said. rate being below that: which causes an accumu-y lation of the fresh feed and' recycle liquid imme diatel'y about the region» of dispersion inthe lower portion of the reaction zone` resulting in a. re duction in the degree. of dispersion of the dropsi anda lowering of theinterface level. atleast a portion of the settled catalyst together with fresh make-up catalyst is returned' directly to the maintained catalyst body without previous mixing with the fresh feed at a level near the 60 lower portionY of the maintained catalyst body. LOUIS A. CLARKE.