US2865971A - Alkylation with effluent refrigeration and flashed vapor absorption - Google Patents

Description

D. K. BEAVON WIT ALKYLATION H EFFLUENT REFRIGERATION AND FLASHED VAPOR ABSORPTION Filed Deo. 25, 1955 KIQ @www mum nited States ALKYLATION WITH EFFLUENT REFRIGERATION AND FLASHED VAPOR AESSURPIION David K. Beavon, Los Angeles, Calif., assigner to The Texas Company, New York, N. Y., a corpuration. of Delaware Application December 23, 1955, Serial'No. 555,386' s claims. (ci. 2604683.62)

of lower pressure where isobutane is vaporized with con` comitant cooling of the remaining liquid hydrocarbons including alkylate, and the resulting cooled or chilled liquid hydrocarbons are utilized to maintain or assist in maintaining the temperature in the alkylation zone by indirect heat exchange therewith. This patent also discloses that the vaporized isobutane from the flash zone is removed and compressed for recycling to the alkylation zone.

Elfluent refrigeration possesses certain advantages over auto-refrigeration of the alkylation reaction zone in which lower boiling hydrocarbons including isobutane are evaporated directly from the alkylation reaction zone. In eluent refrigeration, the alkylation zone and settler are maintained under sufficient pressure to prevent evaporation of any substantial amount of the lower boiling hydrocarbons and thereby to insure keeping isobutane and other reactants in liquid phase, whereby the desired high molar excess of liquid isobutane over olefin is maintained throughout the alkylation zone.

Patent No. 2,334,955, Putney, also discloses effluent refrigeration in catalytic isobutane-olen alkylation, and suggests that a portion of the chilled hydrocarbon liquid from the ash zone can be passed in indirect heat exchange with the feed or" reactants to the alkylation zone (page l, column 2, lines 35-39). This patent teaches the principle in eflluent refrigeration of dividing the refrigeration load for the alkylation step between elliuent refrigeration supplied to the alkylation zone and effluent rer'rigeration supplied to pre-chill the feed to the alltylation zone.

Patent No. 2,664,452, Putney, teaches a further improvement in elliuent refrigeration involving a double flash drum arrangement for accomplishing this division of the refrigeration load for the alkylation zone. Thus, vaporized propane and isobutane from the rst flash zone, which supplies the chilled hydrocarbon liquid used for refrigeration of both the alkylation reaction zone and also the feed to the alkylation zone, is compressed and condensed; recycle and make-up isobutane and the coridensate are passed to a second llash zone of lower pressure where a portion of the isobutane and lighter hydrocarbon including propane is vaporized With resultant chilling of the remaining liquid isobutane. The ashed hydrocarbons are passed to the alkylate fractionating system for depropanization and other fractionation. The chilled liquid isobutane from the second flash zone is bien recycledvto the alkylation zone. The second flash atet assert Patented Dec. 23, 1958 zone producing chilled liquid isobutane thereby absorbs part of the refrigeration load, and reduces the refrigeration requirements of the irst flash zone in order to maintain the desired temperature of the alkylation reaction zone.

Preferably strong sulfuric acid of about 88-98% strength is used as a catalyst in alkylation processes employing effluent refrigeration, although other liquid alkylation catalysts which are non-volatile under the conditions at which isobutane is vaporized in the flash drums for effluent refrigeration, e. g., aluminum chloride-hydrocarbon complex liquid catalyst, can be employed. These catalysts generate volatile sour degradation products in reaction mixture under reaction conditions, e. g., SO2 in the case where sulfuric acid is a catalyst, and I-lCl in the the case where aluminum chloride-hydrocarbon complex liquid is the catalyst. The very high volatility of these acidic materials permits them to escape from flash zones with the volatilized hydrocarbons and to cause corrosion in the apparatus used to recover and separate hydrocarbons ultimately from the flashed material where moistur-e is present. Corrosion is particularly bad in the depropanizer fractionating tower and in vessels receiving wet make-up hydrocarbon streams such as make-up olen or make-up isobutane.

The present invention relates to an improvement in effluent refrigeration, for example of the double flash zone type as represented by the Putney Patent 2,664,452. ln accordance with my invention vaporized isobutane, propane, andl sour degradation products are removed from the rst liash zone, then compressed and partially condensed. Vapors and liquid are separated in a second zone maintained at substantially compressor discharge pressure, so that the vapors consist mainly of propane and acidic gases while the liquid is isobutane relatively free of these components. The condensate is passed to another low pressure flash zone wherein additional propane, acidic gaseous degradation products, and a portion of isobutane are revaporized with resultant chilling of the remaining condensate. Vapors from said other low pressure ash zone are commingled with vapors from the lirst flash zone' for compression, while the chilled remaining condensate from said other llash zone is recycled as feed to the alkylation zone. The vapors from the second zone, comprising uncondensed propane, acid gases and isobutane, are absorbed at elevated pressure in the fraction of hydrocarbon liquid comprising crude alkylation products which is withdrawn from the first flash zone for subsequent neutralization and fractional distillation into product, by-product, and recycle streams. This fraction of hydrocarbon liquid (herein termed flashed crude alkylate for convenience) and the absorbed vapors are both neutralized, and the resultant neutralized mixture of hydrocarbon liquid and absorbed vapors are then fractionally distilled to obtain product alkylate, to rid the system of low boilers such as propane, and to recover unreacted excess isobutane for recycle to the alkylation zone'.

The absorption step in my process can be conducted with the un-neutralized' flashed crude alk'ylate prior to or during itsl neutralization or after this crude hydrocarbon mixture has been neutralized and still remains admixed with neutralizing solution, e. g., aqueous caustic soda, soda ash-or the like. The caustic treated mixture is then water washed and'passed to a fractionating system.

My process is based on the realization that the dashed crude alkylate liquid leaving the lrst flash zone of lower pressure has considerable absorption capacity for propane andl isobutane at a pressure above about 30 p, s. i. g.; broadly at pressure between about 40 andy about 100 p. s. g., and typically at 52455 p. s. i. g. By this absorption,y low boiling' vaporized components such as prol* pane, ethane, and lighter materials and sour volatile substances are removed from the alkylation system quite readily; the subsequent neutralization of the acidic volatile degradation products contaminating these vaporized components protects the expensive fractionating equipment in the subsequent processing steps without necessitating extra neutralization apparatus.

The invention is illustrated in the attached drawings wherein Fig. 1 represents a flow diagram of a typical alkylation plant employing an alkylation reactor of the internal recirculated type, e. g., a so-called Stratco- Contactor, although my invention can be also applied to other conventional types of alkylation reactor systems such as the pump and time tank type. In this embodiment, absorption of vapors is done in a vessel pro-vided for this purpose. Fig. 2 shows a modification of my invention wherein the vapors vented from the second flash zone are contacted for absorption and neutralization with neutralized flash crude alkylate as it is still in contact with a caustic solution.

Referring to the drawing, the olefin feed stream is introduced by line 18 and make-up isobutane is added thereto by line 11. It will be understood that the olefin feed stream is generally a C4 cracked gas fraction containing butanes and butylenes and termed BB feed, preferably one which contains less than about 30 liquid volume percent of normal butane. However, a mixed (S3-C4 olefin feed stream can be employed, or other normally gaseous and normally liquid oleiins can be used. The resulting feed stream, mixed with recycled recovered isobutane from line 12, is passed through feed exchanger 13 which is chilled by effluent refrigeration as described hereinafter. It is then introduced by line 14 into water separator 15, where, as a result of chilling and standing, a water layer is decanted and withdrawn thro-ugh line 16. The feed containing recycled isobutane is then passed through line 17 into header 18, together with a chilled liquid recycle fraction from the third flash drum, hereinafter described, entering header 18 from line 46.

Line 18 discharges into contactor 19. The liquid acid: hydrocarbon volume ratio in the contactor 19 is maintained about 1:1 and a contact time in the contactor is about to l5 minutes in the conventional manner. Where sulfuric acid is utilized as catalyst, make-up 98% H2804 is added to the system through line 24 to keep the acid strength in the contactor at about 8892% strength. Mol ratio of isobutane to olefin supplied to the contactor (including isobutane recycle) is substantially in excess of 1:1 and generally is about 4:1 to 10:1. The eiuent hydrocarbon-catalyst mixture is withdrawn from the contactor through line 20 and passed through settler 21 where the heavier catalyst phase is separated from the hydrocarbon phase. The catalyst phase is recycled to contactor 19 through line 22, with catalyst purge being withdrawn through line 23 and make-up catalyst being added through line 24 to maintain desired acid strength in the contacting system.

The lighter hydrocarbon phase is withdrawn from the top of settler 21 through line 2S and passed into first flash drum 26. Here the pressure is dropped from about 25-40 p. s. i. a. existing in the alkylation and catalyst settling system to approximately atmospheric pressure or below by connecting the suction side of compressor 39 through vapor line 34 to the upper portion of first flash drum 26. This results in isobutane and lighter hydrocarbons including propane being vaporized in' the lirst iiash drum with resulting chilling of the remaining unvaporized hydrocarbon liquid to about F. or lower. A portion of the so-chilled hydrocarbon liquid s withdrawn from tiash drum 26 by line 3l), pump 31, line 32 to feed exchanger 13 to pre-chill the feed to the alkylation zone. This portion of the hydrocarbon liquid (the flashed crude alkylate) is then passed by line 33 to absorber 48. Another portion of the chilled hydrocarbon liquid .from flash drum 26 is passed by line 27 to the chilling coils in the alkylation contactor, the distributing head of said chilling coils being represented symbolically in the drawing by item 28. ln the arrangement sho-wn ash drum 26 is elevated above the chilling coil so that gravity flow is utilized to convey the chilled hydrocarbon liquid through line 27 to the chilling coils. In the coils a portion of the isobutane and lighter hydrocarbons is vaporized to provide refrigeration with an incidental thermosyphon eliect which returns mixed liquid and vapor through line 29 into the iiash'drum 26. However, it will be understood that a pump can be provided for positive circulation through the cooling coils in contactor 19.

Vaporized isobutane, propane, and sour degradation products removed from liash drum 26 by vapor line 34 pass into compressor trap 35, wherein any heavier er1'- trained liquid drops out and can be removed by pump 36 and line 37. The vapors then pass by vapor line 38 to compressor 39 which raises the pressure thereof to about 52-55 p. s. i. g., and forces them by vapor line 40 through water cooled condenser 41 and line 42 into second ash drum 43. Drum 43 is, in this case, primarily a disengaging chamber, but is called a tiash drum herein for convenience. Uncondensed vapors from the second flash drum are withdrawn through line 47.

The condensate from second tiash drum 43 is released 'by pressure regulating valve 143 thru line 44 into third flash drum 103 (which is operated at approximately atmospheric pressure) whereby additional propane, volatile sour degradation products, and a portion' of isobutane are revaporized with the resultant chilling of the remaining condensate. The vapo-rs from third flash drum 103 ow through line 145 to compressor trap 35, joining vapors from first flash drum 26 passing thereto. Chilled condensate, preponderantly isobutane, is withdrawn from third ash drum 103 by lin'e 144 and pump 4S, then passed through line 46 into header 18 for recycle into contacto-r 19. Thus the isobutane recycle from the third iiash drum is utilized to further chill the feed to the alkylation zone by mixing therewith, thereby distributing the refrigeration load between the first and third flash drums.

The uncondensed vapors from the second ash drum are passed by line 47 into absorber 48 wherein they are contacted with liashed crude alkylate from line 33 after it has been used to chill the feed exchanger 13. The absorber pressure is essentially the same as that in the second liash drum. The mixture of flashed crude alkylate enriched by absorbed vapors from the second flash drum comprising propane, isobutane, and sour degradation products, is withdrawn from the absorber by line 49, pump 50 and line 51 for feeding into conventional caustic mixer 52. If desired, a portion of the flashed crude alkylate can be diverted from absorber 48 to the caustic washer by means of bypass 33a.

In caustic washer 52 the enriched iiashed crude alkylate is thoroughly mixed and neutralized with a recycle iiow of aqueous 5% by weight of caustic soda. The mixer eftiuent is passed through line 54 into settling tank 55 wherein it is separated into an upper hydrocarbon phase and a lower aqueous phase. The aqueous phase is withdrawn from settling tank 55 by line 56 and recirculated into line 53 by pump 59. Spent caustic solution can be withdrawn from line 57 and make-up caustic solution added through line 58.

r)The neutralized hydrocarbon phase is Withdrawn from settling tank 55 through line 60, mixed with water (entering line 61) in mixer 62, and this mixture conducted through line 63 into settling tank 64 wherein a lower water phase and an upper hydrocarbon phase are formed. The water phase is withdrawn from settling tank 64 by line 65.

The upper hydrocarbon phase is passed through line 66 into depropanizer tower 67. This tower is operated to make a sharp separation between propane'and lighter hydrocarbons, removed by overhead vapor line 68, and

C4 and heavier hydrocarbons, removed as a bottoms fraction through line 75. Propane vapors from tower 67 are condensed in condenser 69 and are discharged through line i into accumulator 71. A portion of the condensate in accummulator 71 is pumped back to the depropanizer as redux, and the remainder is discharged from the system by means of line 72.

The depropanizer bottoms are passed by line 75 into deisobutanizer tower 76. This tower is operated to make sharp separation between isohutane and normal butane and heavier to thereby remove overhead, by vapor line 7S, an essentially isobutane vapor which passes through condenser i9 into accummulator 80. A portion of the isobutane condensate is pumped through line 81 as retlux to the deisobutanizer. The remainder of the isobutane condensate is passed through line 12, optionally through a water pre-cooler, and then mixed with the olefin and isobutane feeds in advance of feed exchanger 13.

The liquid product from deisobutanizer 76 passes by line 82 to product debutanizer 84 where normal butane is removed overhead by vapor line 86 through condenser 87 to accumulator 88. A portion of the liquid normal butane is reuxed by pump to debutanizer 76 through line 89, and the balance is discharged by line 90 to tankage for feed to an isomerization unit, or as blending stock, or for other purposes.

The debutanizer bottoms fraction passes by line 91 to fractionator 93 wherein the desired aviation alkylate or high octane motor gasoline alkylate fraction is removed overhead through line 95 and condenser 96 into accumulator 97. A portion of the condensate is returned as reflux to the fractionator by line 98, and the remainder discharged to tankage by line 99. The heavier alkylate bottoms are withdrawn through line 100, cooler 1101, and line 102 to tankage to serve as cracking stock or for other uses.

in the foregoing drawing only the principal pumps have -been shown and fractionating tower reboilers are `indicated symbolically at the bottoms of the towers. Ad-

ditional pumps and various auxiliary equipment can be supplied in conventional manner where necessary or desirable, and the order of flow through the various fractionating towers can be changed as is necessary or desirable without departing from the principles of this invention.

Fig. 2 shows a modilication of the scheme hereinbefore described. The numerals in Fig. 2 correspond to the equipment items enumerated in Fig. 1. in this special case wherein flash drum 43 is operated at a considerably higher pressure, e. g., to 15 p. s. i., than the caustic settling tank 55, vapors from dash drum 43 can be contacted directly for absorption in the neutralized flash crude alkylate emerging from mixer 52 with the caustic soda solution. Neutralization of the vapors and absorption of the hydrocarbon vapor take place essentially simultaneously and eliminate a separate absorbing vessel and pump. 1f desired a booster compressor and necessary auxiliary equipment can be installed to take suction out of the flash drum 43 forpassing it into the discharge of mixer 52, or into lines 33 or 53 feeding the mixer. The latter modification permits the operation of flash drum 43 at somewhat lower pressure than either of the schemes outlined in Figures 1 or 2.

The following is given as an example of the present invention, and it represents the operation of a 1750 barrel per day aviation alkylate plant according to scheme shown in Fig. 1. An olefin feed stock is introduced through line 10 at a charge rate of 80 bbl./hr. with a composition in liquid volume percent of 6.6% propane and lighter, 19.0% isobutane, 51.0% butylenes, 20.4% normal butane, and 3.0% C5s. Make-up isobutane from line 11 is introduced at the rate of 38 bbls./hr. with a composition in liquid volume percent of 10% propane, 87% isobutane, and 3% normal butane. This is mixed with.recycledisobutane from line `12 introduced-at the rate of 77 bbL/hr. -with a composition'in liquid volume percent 10% of-C3, ,-87% isobutane, and-.3% normal butane. The foregoing mixedfeed, at a temperature of approximately `"-F.,fpasses through exchanger 13 and is chilled to 60 F. by hydrocarbon effluent from dash drum 26 having a temperature of 30 F. at the entry to exchanger 13 anda temperature of 80 F. at the exit thereof. vThe resultant chilled vfeed-is then mixed with chilled recycled isobutane from flash drum 43, supplied at a temperature of 13 -F. and at feed rate of 156 bbl./-hr.,with arcomposition in liquid volume percent of 9.7% C3, 73.6% isobutane, 15.7% normal butane and 1% .C5 and heavier. The total reactor hydrocarbon charge of 351 bbl/hr., with l,a composition in liquid volume percent of 9%.C3, 66% isobutane, 12% butylenes, 12.5% normal butane,.and 0.5% C5 and heavier, is supplied to the alkylation contacter at a temperature of about 40 F.; 1 bbl./hr. of make-up of 98% i-H2SO4 is supplied together vwith 229 bbl/hr. of recycle H2SO4 tothe alkylation reaction zone, thereby giving a hydrocarbon to acid volume ratio in the -contactor of 1:1 with a maintained system acidity of about 92% HZSOp Hydrocarbon efuent, removed from settler`21 by line f25 to `flash drum `26 at the rate of 333 bbL/hr., has composition in liquid volume percent of 9% C3, 55% yisobutane, 13% normal butane, 1% C5, and 22% alkylate. In flash drum 26 the pressure is dropped to 15 p. s. i. a. with resulting dashing of l206 bbL/hr. of vapo-rs having approximate composition in liquid volume percent of 17% C3, 69% isobutane,13% normal butane, and 1% C5 and heavier. 126 bbl/hr. of chilled hydrocarbon liquid for refrigeration is thus provided having a composition in liquid volume Apercent of 27% -isobutane, 13% normal butane, 1% C5,and about 58% alkylate. This chilled hydrocarbon liquid passes through feed exchanger 13 where its temperature is'raised to 80 F then flows thro-ugh line 33 to absorber 48.

The vapors from line 38 are compressed, partially condensed, and admitted to-flashdrum 43. Herein some additional dashing takes place atfpressure of 69p. s. i. a.

`anda temperature about 80 F., resulting in separation of 51 bbL/hr. of vapors having-approximate composition inliquid volume percent of 30% C3, 64% isobutane, 6% normalbutane together with volatile acidic degradation products.

LiquidV condensate from flash drum 43 (-215 bbl./hr. containing approximately 19% propane, 66% iso-butane, 14% butane, and 1%y C5) iiows through line 44 and thro-ttle valve 143 into third flash drum 103, which is maintained at essentially 15 p. s. i. a.; pressure. The flashing liquid auto-refrigerates to a temperature about 13 F. Vapors are produced (59 bbl./hr. containing approximately in liquid volume percent 45% propane, 47% isobutane, and 8% butane). These vapors iiow through line 145 into compressor trap 35, joining vapors from first ilash drum 26.

From drum 103, 156 bbl/hr. of chilled hydrocarbon liquid refrigerant are thus provided having a composition in liquid volume percent of 9.7% C3, 73.6% isobutane, 15.7% normal butane, 1% C5. This is passed through line 144, pump 45, and line 46 into header 18 for recycle to the contactor.

The vapors from second ash drum 43 are absorbed in flashed crude alkylate from line 33 at pressure at about 65 p. s. i. a. The so-enriched crude alkylate is neutralized with caustic soda solution in mixer 52, decanted in settling tank 55, water washed in mixer 63, and redecanted in settling tank 64 for transmission to depropanizer 67.

Feed to the depropanizer amounts to 177 bbL/hr. having composition in liquid volume percent of 8.5% C3, 38% isobutane, 11% normal butane, 1% C5, and about 41% alkylate. The depropanizer overhead is removed through line 72 at the rate of 15 rbbL/hr. This provides a depropanized bottoms at the rate of 161 bbl./hr. which is passed to deisobutanizer 76.

An'overhead from the isobutanizer is passed through line 12 as recycled isobutane at the rate and in the composition hereinbefore described for mixing with charge olefin and make-up isobutane. The bottoms from the deisobutanizer are fractionally distilled in product debutanizer 84 to obtain butane as an overhead product. The alkylate bottoms from product debutanizer 84 are fractionaily distilled in fractionator 93 to produce an Overhead product of about 66 bbl./hr. aviation alkylate, which is withdrawn through line 99, and 7 bbl./hr. of heavy alkylate, which is withdrawn through line 102.

Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. In a process for catalytic isobutane-oleiin alkylation employing eiiuent refrigeration, wherein isobutane in molar excess and olenic feed stock containing some propane are contacted in liquid phase in an alkylation zone with a liquid catalyst under alkylating conditions, said catalyst being capable of generating volatile acidic degradation products in the reaction mixture under reaction conditicns, the resulting reaction mixture is separated into a liquid hydrocarbon phase and a liquid catalyst phase, separated liquid hydrocarbon phase is passed to a ash zone of lower pressure to evaporate isobutane, volatile acidic degradation products, and propane therefrom and concomitantly chill the remaining hydrocarbon liquid comprising the crude alkylation product, at least a portion of the chilled hydrocarbon liquid is employed as a heat exchange medium to assist in controlling temperature in said alkylation zone, and the remainder of said chilled hydrocarbon liquid comprising the crude alkylaticn products is withdrawn from said tiash zone of lowerl pressure for subsequent neutralization and fractional distillation, the improvement which comprises: removing a stream of evaporated isobutane, propane, and volatile acidic degradation products from said flash zone of lower pressure; compressing said stream and con- -densing liquid isobutane therefrom; separating the resulting sour vapor phase from the condensed liquid isobutane-containing phase; absorbing the resulting sour vapor phase at elevated pressure between about 30 and 100 p. s. i. g. in said remainder of hydrocarbon liquid comprising crude alkylation products; and neutralizing both said remainder of hydrocarbon liquid and the vapors absorbed therein.

2. The process of claim 1 wherein said liquid catalyst is sulfuric acid, and the absorption step is conducted prior 8 to neutralization of said remainder of hydrocarbon liquid comprising crude alkylation products.

3. The process of claim l wherein said liquid catalyst is sulfuric acid, and the absorption step is conducted concurrent with neutralization of said remainder of hydrocarbon liquid comprising crude allcylation products.

4. In a process for catalytic iso-butane-olefin alkylation employing efliuent refrigeration, wherein isobutane in molar excess and olenic feed stock containing some propane are contacted in liquid phase in an alliylation zone with a liquid catalyst under alkylating conditions, said catalyst being capable of generating volatile acidic degradation pro-ducts in the reaction mixture under reaction conditions, the resulting reaction mixture is separated into a liquid hydrocarbon phase and a liquid catalyst phase, separated liquid hydrocarbon phase is passed to a flash zone of lower pressure to evaporate isobutane, volatile acidic degradation products, and propane therefrom and concomitantly to chill the remaining hydrocarbon liquid comprising the crude alkylation product, at least a portion of the chilled hydrocarbon liquid is employed as a heat exchange medium to assist in controlling temperature in said alkylation zone, and the remainder of said chilled hydrocarbon liquid comprising the crude alkylation products is withdrawn from said dash zone of lower pressure for subsequent neutralization and fractional distillation, the improvement which comprises removing a stream of evaporated isobutane, propane and volatile acidic degradation products from said dash zone of lower pressure. condensing isobutane from said stream and separating the resulting remaining sour vapor phase from the condensed liquid isobutane phase, absorbing said separated sour vapor phase in said remainder o-f hydrocarbon liquid comprising crude alkylation products at elevated pressure between about 30 to 100 p. s. i. g., and neutralizing both said remainder of hydrocarbon liquid and the vapors absorbed therein.

5. The process of claim 1 wherein the separated condensed liquid isobutane phase is reashed in a subsequent dash zone of lower pressure, the resulting vapors and residual chilled isobutane are separated, said last-mentioned resulting vapors are combined with said stream of evaporated isobutane, propane and volatile acidic degradation products, and said last-mentioned residual chilled liquid isobutane is returned to said alkylation zone.

References Cited in the tile of this patent UNITED STATES PATENTS 2,342,364 Parker Feb. 22, 1944 2,370,771 Bowerman Mar. 6, 1945 2,374,262 Anderson Apr. 24, 1945 2,664,452 Putney Dec. 29, 1953

Claims (1)

1. IN A PROCESS FOR CATALYTIC ISOBUTANE-OLEFIN ALKYLATION EMPLOYING EFFLUENT REFRIGERATION, WHEREIN ISOBUTANE IN MOLAR EXCESS AND OLEFINIC FEED STOCK CONTAINING SOME PROPANE ARE CONTACTED IN LIQUID PHSE IN AN ALKYLATION

Images