US2509028A - Method of producing gasoline by alkylation and reforming - Google Patents

Description

May 23, 1950 A. J. ABRAMs Er Ax.

METHOD oF PRoDucING GAsoLmE BY ALKYLATION REFORMING 2 Sheets-Sheet l Filed July 19, 1945 CARL J. HUA/l1, da.

.lNVENTOR May 23, 195o A. J. ABRAMS ETAL 2,509,028

METHOD 0F' PRODUCING GASOLINE BY ALKYLATION REFORMING 2 Sheets-Sheet 2l Filed July 19, 1945 INVENTOR ,com

Patented May 23, 1950 Applicationrluly 19, 1945,;seriairuwoaasa I2 (cl. 26o-683,4)

7 This `aplolication. isa continuation-irl-part; f.

our -copendina application Serial No. 431.95816, filed April..l2,. 1,942,` andl now. abandoned..

This; inventionrelates .toithe catalytic, marin;r

lfacture of. high.octane.,gaso1ine, The inyention is directed particularly. toa.- method'of catalytically reforming a, relatively narrow boiling, iso.- parafn fraction. suchasforzexample. aztypical paraftinic` alkylate, so. as-: to; :gia/e. a complete-.gaso: line of high l.octane-.value The`r alkylation of.` isoparariic;` hydrocarbons with, olenic, hydrocarbons` for v theproduction-of isoparafns .of `high octane valueizboiling in;l the gasoline range is now a well;.established: fart. Henetofore, various catalysts havebeenrprfoposed for this reaction, such. as. sulfuric ,acid,..'phos phoricracid, Y aluminum .chloride etc. t has morearecently. been discovered. U. S.'Patent;No. 2,2613730Mthat aklyla-tion `reactions off ther .above type .may be carried.. out in. a highly desirable manner by using a catalyst consisting .essentially fofhydrogen fluoride;

f Sin-ce -aikylation processes,. as usually;l con.-v d-ueted, effect predominantly the conderzusation` of one particular isoparan. -With-oneparticular olefin, Ythe resulting. alkylate gaso1ine,..-.althcugh lo-fhigh octane value; is. composed-.predominantly of-1 isomers of 'ionef paraflnic'- hydrocarbon Therefore, the alkylateis ofmelativelylnarrow--boiling range which is liess than-that of 4a complete gasoli-ne Vorf-at leastysuch allay-latel doesl not 1- haver-a uniform Adistribution -o'f hydrocarbons across the desired gasoline boilingrange'. Asis -Wellknown, gasolineslshouldl be ofY adequate `boiling'range and have their constituents rather` uniformly -dis- V`catalytic re-a'rrangem'ent vor reformingk ofisoparafins'y Vsuch' as alkylate hydrocarbons; boiling inthe gasolinera-nge to yield' a compos-itegaso- 'line which boils over lan entire gasoline rangea-nd lwhichpossesses substantially as high an :antiknock 'value as a blendedA alkylate gasoline6 ln accordance with that invention, therefrislshown,

for example,V a process of reformingjisoparafns Y inv the lpresence of hydrogen 'uoridefto yield? a hydrocarbon mixture wlhichboils over yan lentire cartons.thatlowenboilinafhndrarbons. be formait'frognthatharae stoclaas.; .well` er boilinahrdrooarbons. Tha present .inveritialis 20 hydrogen .Euer-ide.. A morespecina object-,1s

to catalyticallysrefotm suchfnarrow boiiinglfzfra: tionsbyfa.noyelemethodtoeobtain a completegaas: .olinefot high oetanevafluefarid properManor131.1125. suretand distillationrfchanacteristicsh Accordingly,.an\embodirnent or ourlinvention is-canrietirout-.by-z feeding. `,an .entire vai-kylation.:reaction mixture.' .containing -hydro-uoric acidi catfalyst into-.a trantionatlng unitfand .the isoparafns. arelreiormedaby further: contact 30 with the hydrogen fluoride catalyst under condi@ tions i, whichl maintain;v materialarof@ gasc'lineelooil-fingrange,arl-iclz lfligher.:in liquidaform whilejliglnter material;v 'includ-ingmydrogen .uoririaA waporizes. These tapers ofilighter material are lecleto'r'a com denser, .and-the condensate thfereirornisalilowe tributed in ordertoinsure proper Carburation 1 l v-toseparate into two-Alayersttvizfy-.anupperohyxitrocar/bon'- layer anti-1aliowenhydrogen.uor;ide layer. Thehycirocarlbon` layer-1 is: composedprimarilymf light isoparai-ns, e. tg. isobutane rana. isopehtane, which are 'le-ft overV from -theifcharge :stoek;...i `present therein,k and which are: produced dur-.ing there-formingstep;l 'The normally liquid hytlro'- carbone or thereactionfmixtureand some hydro gen fluoridearelwitladraWn-fromthe: fractionating unit in -liquidform and'- ltreatediti-1a manner l'aterAdescr-ibedf.

For a. -f-ullerur-nierstandingof .the invention, reference will befmade tor-the aocompanyin-gttraw- 'ings-f- W-hereinu-Fiigure -lshowslldiagrammatiicaily .59 'av prefer-red.Y apparatus l setup" for conducting; our

process; Vand '-lFigure y-2iy 'is a graph showing' the ability @Pour reita-mingy process to: produce-)new products ofvastiystliiferent-distillationichanactera gasoline range. It* isf-especially interesting. to 'isti'csf-from -narrow boil-ing. ractioJrIs-.cty \.gaso1ihe note that this processis :capableofefecting such 55 boiling-r .isopa-rains. acompletencorrversionforfactionotthe hyciroe VInf-operatiori-riet'err-ing .lnoWL-.toi Fifgureffil--a suitable isoparaflinic charging stock is fed continuously through lines I and 2 onto a feed plate 3, in the middle of column 4. Column 4 may perform the dual function of a fractionation and a reforming chamber, and is suitably constructed for effecting proper contact of isoparaiins and HF. Lower boiling liquid isoparaftlns are used as a reflux for column 4, and are introduced by line 5 to distributor 6. In order to afford still greater exibility of operation in column 4, provision is made for introducing liquid HF through line 'I to column 4 at a point below where reaction mixture is fed in. This serves to increase the quantity of HF in contact with the high boiling hydrocarbons and, therefore, the extent of reforming-all other factors being constant. Provision for returning additional liquid HF to the bottom section of the column can be made by recycling a part of the HF from gravity separator 8.

`Conditions within the column 4 are maintained so that gasoline boiling hydrocarbons and higher boiling hydrocarbons remain liquid and are drawn oi at the bottom of the column through pipe I'I. Lighter hydrocarbon material and a portion of the hydrogen fluoride vaporize and the resulting vapors pass upwardly through the column counter-current to the down-flowing liquid. These vapors are led from the top of column 4 through line 9 to condenser I0. The condensate from condenser IU is led through line II and line I2 to gravity separator I3, and a part also may be recycyed through line Il and line I4 to reaction Vessel I5, containing high-speed mixer I5a. The condensate in separator I3 separates into two layers, namely, an upper hydrocarbon layer and a lower hydrogen fluoride layer. The upper hydrocarbon layer in separator I3 passes through line 5 to column 4 as reflux, and the lower hydrogen fluoride layer in separator I3 passes through line I to the bottom of column 4, both as explained hereinabove. If desired, however, any part of either of the two layers in separator I3 might be sent to reactor I5 by suitable pipes (not shown) Additional hydrogen fluoride as needed may be introduced to the system through line I6.

The crude reformed product is withdrawn from the bottom of column 4 through line I'I and passed into gravity separator 8. Here the product separates'from accompanying liquid HF to form two layers. The product layer is taken through line I8 to fractionating and/or refining equipment (not shown). The HF in separator 8 is removed through line I9 and passed thereby back to reaction vessel I5, or it is diverted from line I9 through line 2li and sent either through line 2I back to the bottom of column 4 or sent through line 22 to an HF purification system (not shown) and the purified HF is returned to the system. This purification system may comprise merely a distillation column for vaporizing HF.

, The liquid product withdrawn from the bottom of column 4 and sent to the fractionation system may be fractionated in order to cut out a. desired gasoline fraction, and the light and heavy ends obtained in this fractionation, may be led either to reactor I5, along with the low boiling isoparans (isobutane and isopentane) taken over-head in column 4, for further treatment in the presence of HF, or may be withdrawn permanently from the reaction cycle. It is usually desirable, however, to return the heavy ends to the reaction vessel I5 along with low boiling isoparamns and HF, in order to increase the yield of gasoline-boiling hydrocarbons. This may be done by means of line 23. These heavy ends behave like olens in reacting with light isopar- Reaction mixture withdrawn from reactor I5 is sent to column 4 via lines 25 and 2.

Therefore, it may be seen that the isopara'lnic material of gasoline boiling range which is sent to column 4 may be derived from several sources. Thus, the isoparailinic charge stock fed through line I may be isoparafns of gasoline boiling range derived from any source, and, of course, might be the reaction mixture of an HF alkylation process. In this latter case, such HF alkylation process may be conducted in a separate reactor or it may be conducted in the reactor I5 along with the other reactions mentioned above as being carried out in reactor I5. In any of these embodiments. ail, any part or none of the materials mentioned above as being recycled to reactor I5 may be so recycled.

Column 4, as explained hereinabove, is preferably both a reforming and fractionating unit and is of appropriate construction therefor. Thus, for example, the section of the column above the feed plate 3 may comprise a series of bubble-cap trays which serve to strip the low boiling hydro'- carbons from the higher boiling hydrocarbons; while the section below this feed piate may be packed with an inert material, as, for example, carborundum, with occasional bubble-cap trays being used as collectors and re-distributors of liquids. It is to be understood that the single column 4 could be replaced by two columns, one of which performs the function of the upper section of column while the other performs the function of the lower section of column 4. Moreover, if desired, the alkylation reactor might be made a section of the column.

The higher boiling hydrocarbons which travel downwardly through the lower section of the column in the presence of the liquid HF are reformed to an extent which is dependent upon: (1) contact time, (2) temperature, (3) ratio of low boiling (usually isobutane) to high boiling hydrocarbons in the mixture, and (4) amount of HF present. These four variables may be adjusted to give substantially any gasoline range material desired. It is a simple matter to substantially completely alter the hydrocarbons of the narrow boiling range charging stock to give a mixture of hydrocarbons which form a complete high octane gasoline of proper distillation and vapor pressure characteristics.

The advantages and improvements effected lby a reforming operation of the type brought about in fractionating-reforming column 4 of our apparatus are best shown, perhaps, by the graph in Figure 2. In this graph per cent volume of gasoline distilled is plotted against distillation temperature, and three curves are given, viz., curves A, B, and C. By referring to this graph, it will be seen that a heptane alkylate, produced by alkylating isobutane with propylene and represented by curve A, is concentrated in a rather narrow boiling range between and 100 C. On the other hand, curve B shows that when this heptane alkylate is reformed (in the absence of added hydrocarbons), a mixture of hydrocarbons isobtained which distills rather uniformly asoegoas 5. overfaneentire gasoline ranges Itfalso-=shouldl1be notedy that the-'reformed 'productis essentiallya totally` dierent product from the original 1 alkylate: Thus, only about'lO to 12%y ofthe-re formed product .boils within the boil-ing rangelof the entire alkylate fraction. Moreover, even the ft() 12% of hydrocarbons remaininginthis same range-needinotnecessarily` be of the same structureL as the original alkylate hydrocarbons. CurveV Cfshows that when added isobutaneis present, modification of the final productl isobtainedlwhich still yields a gasoline boiling -rather uniformlyover theentire gasoline range but havlngf'a higher concentration of hydrocarbons .in the:-middle portion of the gasoline. Thisconcentration of hydrocarbons in the middlefporA tion-of the gasoline can be varied. to .almost any extentby the. present invention which removes the-light hydrocarbon gases fromv thel alkylate prior to-separation of HFfrom the` alkylate. This eieotfof .the isobutane apparently" is vone--ofmass action:l

The temperature for reformingisoparans in the presence of. HF may be between, sayabout -eland about A200," C., dependingV upon the desired operating. pressureand the reactivity. of fthe isoparailins.. Providing suicient contact timein th'ecolumn... to attain. thedesired amount of re-V forming, presents no.-.particular problem.V The ee'ctobtained by varying the amount vof light gaseous. hydrocarbons and also.- hydrofluoric acid has .been describedabove, as wellfasmeans for attainingssame. Therefore, it should be apparent thatuathe. variables of the processare subject .tov completelccntrol, and maybeeasily correlated vto givethe. desired result.

An outstanding feature of our. process resides in thefact that light. gaseous ends. are removed from .the `reaction mixture. .in thepresen'ce. of an exeessoof HF, and bymeansof'I-IF, and before. the.=remainder of the hydrocarbons are. separated. froml As a result, we are. able toexert .a greater influence on thev reforming stepandregu.- latertoa ner degree the characteristics. of the products. Thus, in most cases, it is desirablev to have the isoparaiilnic charging lstock freeoflow boiling.A isoparaiilns, including even. thesmall arnountzproduced during reforming, before .separating-.theproductfrom-HF. This, of course, issaccomplishedeasily by the presentprocess.

Itsis perhapsv well to note at this. time that the distillation of two irnnriiscible` liquids.such,as a mixtureofliquid HF. and. liquid hydrocarbons, fol! lcwsa steam distillation principle. according tothe-equation Wnrweightof HF in overheadvapors Wnd=weight of hydrocarbon in overheadV vapors Bnn=vaporpressure of HF at temperature t Pnc=vapor pressure oi' hydrocarbon. at tempera-f turet.

Marr-:molecular weight ofA HF in, vapor phase at temperature t M`1r c ,=.molecular weight of hydrocarbon vapor at temperaturet.

However," HF is highly associatedin the Avapor phase-and its apparent molecular weight varies fromabout 77 at -i0 C. to about: 25 at 130: C. Itf will' beseen, therefore, that War/WHC: decreaseswith increasing temperature..A According@ lyfit-afollows that; a more. complete separation.- yof Hiifrom; -sobutaneby distillation .canV bei obtained 6. at.higherwtemperatures;k Therefore?. iii desired the operation in .column 4 maybe conxluctedifrat temperatures which Y are substantially above i. the boiling fpoint of hydrogen uorideat atmospheric pressure (which-is 19.4 0.); both-because of fthe above reasonv and also-because-a higher A reforming temperatureis thereby maintained:

The amount-of HF'chargedto the columnein excess of that vleavingthe columnas overhead 1 the distillation step involved in our reforming operation is` eliminated; However, it -is to noted that to 99% acid lis analkylating agent of higher specificity and may be used The process describediabove is also described in our co-pendingapplication Serial No.. 43935162 filed April 12', 1942 and now abandoned.

1. The processof producing.v a relatively wide boiling mixture of vhigh quality gasolineboiling hydrocarbons from a relativelyy narrow boiling alkylate produced byr anwalkylatijon stepjfzherein light t iso-parafiins are reactedvjwith, lolefins under alkylating conditions in thepresencewof acatar. lyst consisting essentially ofghydrogeniluoride, which comprises` passingv alkylation reaction mixture comprising relatively` narrow.v boiling, alkylate gasoline.. normally gaseous hydrooarv bons, and hydrogen fluoride to a fractionating; reforming zone,A maintaining said zone under such conditions that normally gaseous hydrocarbons are vaporized while gasolineboilinghydrocarbons and higher, hydrocarbons remain inv the liquid state, continuing. tol contact said alkylate with said hydrogen fluoride `in said.frao v tionating-reforrnng. zone; until substantial ref forming ofthe alkylate is effected,l fractionating off the normally gaseous .hydrocarbons from said' zone duringthe reformingoperationas ayapbr mixture with hydrogenl-uoride, withdrawing, a. mixtureY of reformed gasoline boiling hydrocarf bons,v .higher hydrocarbons. and` hydrogen fluoride in liquidphase from near.v the bottom of said.

zone, condensing said vapor.v mixture .and sepaf rating the condensate into ahydrocarbonlayerand ahydrogen uoride layenpassing thehy;n drocarbon layer. to. the top ofsaid fractionation zone as reux and passing the hydrogen fluoride layer to said. Zone.. at a point neartbe bottom thereof, separatingI said. withdrawnliquid mix:- ture into a hydrocarbon.. phase and ahydrogen fluoride.. phase,v fractionating. said hydrocarbon phase. to produce a. gasoline. boiling4 fraction-:and a fraction of` higher boiling, liquidhydrocarbons, and returningthis latter fraction to the alkylar; tionstep.,.

2., The rprocess. of claim 1.whereintne contact between the. hydrogen uoride vand the ,normally liquid. hydrocarbons in, said fractionatingg'e-r forming.. zone is .suicientto produce. ay .complete gasoline. of proper distillation andvapor. prese. sure characteristics.` n t 3. The.Vv process ofproducing highqualitygasb: line from a relatively narrow boiling; alkylate produced by? an alkylation,stepwherein light..,isoe lla-radins arefreacted withlolens runder; aalliyltf lng conditions inthe presence of a catalyst consisting essentially of hydrogen fluoride, which comprises passing alkylation reaction mixture comprising relatively narrow boiling alkylate gasoline, normally gaseous hydrocarbons, and hydrogen fluoride to a fractionating-reforming zone, maintaining said zone under such conditions that normally gaseous hydrocarbons are vaporized while gasoline boiling hydrocarbons and higher hydrocarbons remain in the liquid state, continuing to contact said alkylate with said hydrogen fluoride in said fractionatingreforming zone until sufficient reforming of the alkylate is effectedvto give a complete gasoline of proper distillation and vapor pressure characteristics, fractionating oif the normally gaseous hydrocarbons from said zone during the reforming operation as a vapor mixture with hydrogen fluoride, withdrawing reformed gasoline and higher hydrocarbons in liquid phase from said zone, fractionating vsaid withdrawn gasoline and higher hydrocarbons to give a gasoline fraction and a, fraction of higher liquid hydrocarbons, and returning said fraction of higher hydrocarbons to said allrylation step for the production of further quantities of gasoline boiling hydrocarbons.

4. The process of producing a relatively wide boiling mixture of high quality gasoline boiling hydrocarbons from a relatively narrow boiling alkylate produced by an alkylation step wherein light isoparaiilns are reacted with oleflns under alkylating conditions in the presence of a catalyst consisting essentially of hydrogen fluoride, which comprises passing allrylation reaction mixture comprising relatively narrow boiling alkylate gasoline, normally gaseous hydrocarbons, and hydrogen fluoride to a fractionating-reforming zone, maintaining said zone under such conditions that normally gaseous hydrocarbons are vaporized while gasoline boiling hydrocarbons and higher hydrocarbons remain in the lid-uid state, continuing to contact said alkylate with said hydrogen fluoride in said fractionating-reforming zone until substantial reforming of the alkylate is effected, fractionating oi the normally gaseous hydrocarbons from said zone during the reforming operation as a vapor mixture with hydrogen fluoride, withdrawing reformed gasoline boiling hydrocarbons and higher hydrocarbons in liquid phase from said zone,

bons to said alkylation step for the production of further quantities of gasoline boiling hydrocarbons.

5. The process of manufacturing high quality gasoline from a relatively narrow boiling alkylate produced by reacting light isoparafns with olens in the presence of a catalyst consisting essentially of hydrogen fluoride, which comprises passing alkylation reaction mixture comprising relatively narrow boiling alkylate gasoline, normally gaseous hydrocarbons, and hydrogen fluoride to a fractionating-reforming Zone, maintaining said zone under such conditions that normally gaseous hydrocarbons are vaporiaed While gasoline boiling hydrocarbons and higher hydrocarbons remain in the liquid state, continuing to contact said alkylate with said hydrogen fluoride in said fractionating-reforming zone until suflicient reforming of the alkylate is effected to give a complete high quality gasoline of` proper distillation and vapor pressure characteristics, fractionating oi the normally gaseous hydrocarbons from said zone during the reforming operation as a vapor mixture with hydrogen fluoride, and withdrawing said high quality gasoline and higher hydrocarbons in liquid phase from said zone.

6. The process of producing a relatively wide boiling mixture of high quality gasoline boiling hydrocarbons from a relatively narrow boiling alkylate produced by reacting light isoparaiiins with oleiins in the presence of a catalyst consisting essentially of hydrogen fluoride, which comprises passing alkylation reaction mixture comprising relatively narrow boiling alkylate gasoline, normally gaseous hydrocarbons, and hydrogen fluoride to a fractionating-reforming zone,

maintaining said zone under such conditions that normally gaseous hydrocarbons are vaporized while gasoline boiling hydrocarbons and higher hydrocarbons remain in the liquid state, con-v tinuing to 'contact said alkylate with said hydrogen fluoride in said fractionating-reforming zone until substantial reforming of the alkylate is effected, fractionating off the normally gaseous hydrocarbons from said zone during the reforming operation as a vapor mixture with hydrogen fluoride, withdrawing gasoline boiling hydrocarbons andhigher hydrocarbons in liquid phase from near the bottom of said zone.

7. The process of claim 6, wherein the distilling off of the vapor mixture of hydrogen fluoride andv normally gaseous hydrocarbons from the fractionation zone is effected by distilling at a tem-v perature which is substantially above the atmospheric boiling point of hydrogen fluoride so as to obtain a relatively low ratio of hydrogen fluoride to hydrocarbons in said vapor mixture.

8. The process of producing a relatively wide boiling mixture of high quality gasoline boiling hydrocarbons from a relatively narrow boiling alkylate produced by reacting light isoparains with oleflns in the presence of a catalyst con" sisting essentially of hydrogen iiuoride, which comprises passing alkylation reaction mixture comprising relatively narrow boiling alkylate gasoline, normally gaseous hydrocarbons, and hydrogen fluoride to a fractionating-reforming zone, maintaining said zone under such conditions that normally gaseous hydrocarbons are vaporized while gasoline boiling hydrocarbons and higher hydrocarbons remain in the liquid state, continuing to contact said alkylate with said hydrogen fluoride in said fractionating-re` forming zone until substantial reforming of the alkylate is effected, fractionating off the normally gaseous hydrocarbons from said zone during the reforming operation as a vapor mixture with hydrogen fluoride, withdrawing reformed gasoline boiling hydrocarbons, heavier hydrocarbons and hydrogen fluoride in liquid phase from said zone, and recycling said normally gaseous hydrocarbons and said heavier hydrocarbons removed from said fractionating-reforming zone to said alkylation step.

9. The process of producing reformed gasoline,v

of relatively wide boiling range from a relatively narrow boiling fraction of gasoline boiling iso-. para'ins which comprises feeding the relatively narrow boiling fraction of isoparaiiins and a catalyst consisting of hydrouoric acid as the eiective catalytic agent to a fractionating-reforming zone, maintaining said zone under such conditions that normally gaseous hydrocarbons are vaporized while gasoline boiling hydrocarbons and higher hydrocarbons remain in the liquid state., contacting said isoparains with said hydrogen uoride in said fractionating-reforming zone until suicient reforming of isoparaflins is effected to give complete gasoline of proper distillation and vapor pressure characteristics, fractionating off normally gaseous hydrocarbons from said zone during the reforming operation as a vapor mixture with hydrogen fluoride, condensing and returning at least a portion of the vaporized hydrogen fluoride to said zone, and withdrawing said complete reformed gasoline and higher boiling hydrocarbons in liquid phase from said zone.

10. The process of producing reformed gasoline of relatively wide boiling range from a relatively narrow boiling fraction of gasoline boiling isoparains which comprises feeding the relatively narrow boiling fraction of isoparaillns and a catalyst consisting of hydrofluoric acid as the effective catalytic agent to a fractionating-reforming zone, maintaining said zone under such conditions that; normally gaseous hydrocarbons are vaporized while gasoline boiling hydrocarbons and higher hydrocarbons remain in the liquid state, contacting said isoparains with said hydrogen fluoride in said fractionating-reforming zone until substantial reforming of the isoparailn is effected, fractionating off normally gaseous hydrocarbons from said zone during the reforming operation as a vapor mixture with hydrogen fluoride, 'condensing and returning at least a portion of the vaporized hydrogen fluoride to said zone, and withdrawing said reformed gasoline boiling hydrocarbons and higher hydrocarbons in liquid phase from said zone.

11. The process of producing a relatively wide boiling mixture of high quality gasoline boiling hydrocarbons from a relatively narrow boiling fraction of gasoline boiling isoparafns which comprises feeding said isoparalns and hydrogen fluoride of alkylation strength to a fractionatingreforming zone, maintaining said zone under such conditions that normally gaseous hydrocarbons are vaporized while gasoline boiling hydrocarbons and higher hydrocarbons remain in the liquid state, contacting said isopara'ins with hydrogen fluoride in said zone until substantial reforming of the isoparains is effected, fractionating offl normally gaseous hydrocarbons from said zone during the reforming operation as a Vapor mixture with hydrogen fluoride, withdrawing reformed gasoline boiling hydrocarbons and higher hydrocarbons in liquid phase from said zone, fractionating said withdrawn liquid hydrocarbons to give a. gasoline boiling fraction and a fraction of higher liquid hydrocarbons, passing said higher hydrocarbons along with light isoparafllns to an alkylation zone, reacting said higher hydrocarbons and said light isoparafllns in said alkylation zone in the presence of hydrogen fluoride of alkylation strength to produce gasoline boiling isoparaifns, and passing these gasoline boiling isoparafhns to said fractionating-reforming zone.

12. The process of producing a relatively wide boiling mixture of high quality gasoline boiling hydrocarbons from a relatively narrow boiling fraction of gasoline boiling isoparailins which comprises feeding said isoparains and hydrogen fluoride of alkylation strength to a fractionatingreforming zone, maintaining said zone under such conditions that normally gaseous hydrocarbons are vaporized while gasoline boiling hydrocarbons and higher hydrocarbons remain in the liquid state, contacting said isoparaflins with hydrogen fluoride in said zone until substantial reforming of the isoparaflins is effected, fractionating off normally gaseous hydrocarbons from said zone during the reforming operation as a vapor mixture with hydrogen fluoride, withdrawing a liquid mixture of reformed gasoline boiling hydrocarbons, higher hydrocarbons and hydrogen fluoride from said zone, condensing said vapor mixture and separating the condensate into a hydrocarbon layer and hydrogen fluoride layer, returning the hydrocarbon layer to the top of said fractionating-reforming zone as reflux and passing the hydrogen fluoride layer to said zone at a point near the bottom thereof, separating said withdrawn liquid mixture into a hydrocarbon phase and a hydrogen fluoride phase, fractionating said hydrocarbon phase to produce a gasoline boiling fraction and a fraction of higher boiling hydrocarbons, passing said Ihigher hydrocarbons along with isobutane to an alkylation zone, reacting said higher hydrocarbons and said isobutane in said alkylation zone in the presence of hydrogen fluoride of alkylation strength to produce gasoline boiling isoparaflins, and passing these gasoline boiling isoparaftins to said fractionating-reforming zone.

ARMAND J. ABRAMS. CARL S. KUHN, JR.

REFERENCES CITED UNITED STATES PATENTS Name Date Arnold July 10, 1945 Number

Claims (1)

1. THE PROCESS OF PRODUCING A RELATIVELY WIDE BOILING MIXTURE OF HIGH QUALITY GASOLINE BOILING HYDROCARBONS FROM A RELATIVELY NARROW BOILING ALKYLATE PRODUCED BY AN ALKYLATION STEP WHEREIN LIGHT ISO-PARAFFINS ARE REACTED WITH OLEFINS UNDER ALKYLATING CONDITIONS IN THE PRESENCE OF A CATALYST CONSISTING ESSENTIALLY OF HYDROGEN FLUORIDE, WHICH COMPRISES PASSING ALKYLATION REACTION MIXTURE COMPRISING RELATIVELY NARROW BOILING ALKYLATE GASOLINE, NORMALLY GASEOUS HYDROCARBONS, AND HYDROGEN FLUORIDE TO A FRACTIONATINGREFORMING ZONE, MANTAINING SAID ZONE UNDER SUCH CONDITIONS THAT NORMALLY GASEOUS HYDROCARBONS ARE VAPORIZED WHILE GASOLINE BOILING HYDROCARBONS AND HIGHER HYDROCARBONS REMAIN IN THE LIQUID STATE, CONTINUING TO CONTACT SAID ALKYLATE WITH SAID HYDROGEN FLUORIDE IN SAID FRACTIONATING-REFORMING ZONE UNTIL SUBSTANTIAL REFORMING OF THE ALKYLATE IS EFFECTED, FRACTIONATING OFF THE NORMALLY GASEOUS HYDROCARBONS FROM SAID ZONE DURING THE REFORMING OPERATION AS A VAPOR MIXTURE WITH HYDROGEN FLUORIDE, WITHDRAWING A MIXTURE OF REFORMED GASOLINE BOILING HYDROCARBONS, HIGHER HYDROCARBONS AND HYDROGEN FLUORIDE IN LIQUID PHASE FROM NEAR THE BOTTOM OF SAID ZONE, CONDENSING SAID VAPOR MIXTURE AND SEPARATING THE CONDENSATE INTO A HYDROCARBON LAYER AND A HYDROGEN FLUORIDE LAYER, PASSING THE HYDROCARBON LAYER TO THE TOP OF SAID FRACTIONATION ZONE AS REFLUX AND PASSING THE HYDROGEN FLUORIDE LAYER TO SAID ZONE AT A POINT NEAR THE BOTTOM THEREOF, SEPARATING SAID WITHDRAWN LIQUID MIXTURE INTO A HYDROCARBON PHASE AND A HYDROGEN FLUORIDE PHASE, FRACTIONATING SAID HYDROCARBON PHASE TO PRODUCE A GASOLINE BOILING FRACTION AND A FRACTION OF HIGHER BOILING LIQUID HYDROCARBONS AND RETURNING THIS LATTER FRACTION TO THE ALKYLATION STEP.

Images