US1693946A - Operation of pressure stills - Google Patents

Description

Dec. 4, 1928. A

1,693,946 J. E. BELL OPERATION O PRES-SURE STILLS Filed .my 26, 1924 5 Sheets-Sheet l l Il! lll 111 if Il l 1|! NNNNNN OR l ATTORNEYS' Dec. 4, 1928. 1,693,946

J. E. BELL OPERATION OF PRESSURE STILLS Filed-.July 2. 1924. s sheets-sheet L2.

INVESTOR vnEell ATTORNEYS` Dec. 4, 1928.

J. E. BELL OPERATION' oF PRESSURE sTILLs 3 Sheets-Sheet Filed July 26, 1924 INVENTOR JnZzeZZ Patented Dec. 4, 1928.

PATENT OFFICE.

JOHN E. BELL, OF BROOKLYN, NEW YORK, V.ASSIGrlNl'()It TO SINCLAIR REFINING- COM- PANY, OE CHICAGO, ILLINOIS, A CORPORATION OF MAINE.

OPERATION OF PRESSURE STILLS.

Application filed July 26, 1924. Serial No. 728,307.

This invention relates tov improvement-s in the cracking of hydrocarbon 'oils and distillates of high boiling point, such as gas oils and the like, to form Amore volatile or lighter hydrocarbon oilssuch asv those which constitute commercial gasoline or pressure distillate.

The invention includes improvements both in the construction and operation of pressure stills, and in methodsand apparatus for pressure distillation.

rlfheinvention relates more particularly to pressure stills provided with reflux towers, and methods of pressure distillation or cracking'l in which the vapors from the pressure still are subjected to a refluxing operation; and the invention includes improvements in the construction and operation of such pressure stills and reflux towers and in the refluxing operation. In particular, the invention includes improvements in the fractionation or fractional condensation of the A vapors from pressure stills, and the preheating of the'feed thereby, whereby the operation of the pressure still lmay be improved, and important heat economies effected.

In cracking hydrocarbon oils for the production of gasoline by distillation under pressure in pressure stills provided with'reflux towers, the crude pressure distillatedischarged from the top of the reflux tower may contain, in addition tothe lighter hydrocarbons suitable as components of commercial gasoline, hydrocarbon of a kerosene character or others even heavier. It has heretofore been customary to subject all of the vapors escaping'from the Vreflux tower to condensation in a water condenser to give a so-called pressure distillate, and then to re-distill the condensate orpressure distillate so obtained in'order to fractionate it and separate amerchantablegasoline therefrom.

This method of condensation of lpressure distillate involves a large and important loss of heat, inasmuch as the heat of the vapors condensed is dissipatedin the cooling water.

in the condenser, and additional heat is then required for the redistillation. In addition to this redistillation, and the heatV required therefor, additional expense is required in handling the pressure distillates.

@ne of the objects of the present invention is to dispense with this redistillation, either partially or entirely, and to recover and utilize inthe pressure distillation the heat, 'or a considerable part of the heat, which the vapors contain, land which is now dissipated and lost. v l

According to the present invention, the vapors escaping from the reflux tower of the pressure still'are caused to pass in indirect Vheat interchanging relation with fresh feed or charging stock for the still, and such fresh feed or charging stock is thereby preheated, while the vapors are themselves subjected to condensation, thus eliminating the use of a water condenserv for their condensation. This indirect heat interchange of the vapors from the still with the fresh feed is advantageously carried out in a countercurrent fractionating tower in which the vapors as they come from the reflux tower are subjected to fractionation or fractional condensation and are separated into a series. of fractions, and the fresh charging stock or feed is progressively heated to higher temperatures by indirect contact with vapors undergoing condensation at progressively higher temperatures.

The invention also provides anV improved means and method for controlling the operation of reflux towers onl pressure stills, and improvements inthe general method of pressure distillation when carried out with such reflux towers. The inventionv enables a marked heat economy to be obtained inthe pressure still, and in its operation, and .provides a combined operation of improved efficiency.

' According to the present invention, the vapors from the pressure still are firstk subjected to a refluxing operation, which may advantageously be a refluxing operation .in which the vapors are directly contacted'with fresh charging stock or oil introduced into lthe reflux tower and into direct contact with the vapors therein. After this refluxing operation, the remaining vapors from the reflux tower, which may contain vapors resulting from vaporization of part of the feed or charging stock (in case special oil or charging stock is introduced into the reflux tower), are subjected to indirect heat interchanging relation with fresh charging stock passing Vadmiziture with this fraction or 'in `ramasse Separate fractions' for introduction into the reflux tower and for regulating and controlling the reiluXing operation therein, may be Withdrawn lroin the succeeding tractionat-ing operation ofthe invention, or fresh charging stool; which has heen employed in cooling and .condensing the vapors undergoing fractionation by indirect heat eX- change may he employed `ier this purpose, or fractionsv of suitable Vcharacter from Aother sources may be employed7 or various fractions from such sources may be employed conjointly.

Tl present invention also provides an improvedniethod of operation which affords close control el: both the .refluxing operation andthe ractionati'ng operation. For regulatingthe reflux operation, a condensed fraction, corresponding to the desiredvdistillate to be Withdrawn from the retluxing operation as a vapor, may be introduced di'- rectly into'the upper part of the reflux tower. Additional feed, for introduction into the reluXing operation, may be introduced in ay separately introduced at a loiver point in the rellux tower. rllhe -lractienating operation may similarly be regulated and controllerh as described in the prior application hereinbetere mentioned, by passing 'the vapors 'from the reflui; tower through a series of' separate ifapor condensing chambers maintained n at progressively lovfei' Ytemperature and reiiuxing regulated part of condensateI from coolerchainbers into direct contact with the vapors in hotter chambers. a Y

By returning a condensed fraction corresponding to the fraction it` is desired to separate, in either the refluxing operation or tion may be employed for introduction into the refluxing operation, and Where the heaviest traction separated in the iraction'ating operacion is so employed, the vapors escaping from the rerluxing peration will not contain substantial amount o1"- hea-vier material.

carrying ouU lthe method or" the present invention, condensates separated in the 'treeV tionL ting operation may be reuxed or otherwise returned to the still, either directly Vor through thereiluning operation, or they mayY vimproved operationin Which the vs be separately disposed of. The heavier condensates separated in the l'ractionating operation may be introduced into direct contact With-the vapors in Athe relluaing operation for controlling and regulating they character or the distillate escaping 'from thereliuning operation; or the lighter condensates may be subjected to scparateicraclring treatment or may be put to other use. Y

The reflui; 'from the rei'luiring operation includes, in addition to the condensed hea V7ier va ners from the )ressure still separatedin the refluxing operation, the unvaporized part or any fresh charging stock, or el any reflux-ed condensate from the iractionating operation, introduced into direct Contact with the vapors subgected to the reflui; operation; and this rellux is returned to tne pressure still for further treatment therein or the production or' additional amounts or the desired "lighter hydrocarbons.

The present invention includes an improved operation in which the vapors from a pressure still are subjected to a reiluxing operation in direct contact with fresh charging` stock to the still and then to a fractionator relief-:ing operation in indirect heat exchange with 'lresh charging stock, and in which, the Yfresh charging stoel; introduced the lirst reiluxing operation may have been, in part er Wholy, employed in indreet heat exchange with the vapors in the lractionating operation or second reiqu l ation.

The present invention also includes an proved operation in which the vapors from a pressure still are subjected to a reilu-ing operation and then to a ifractionating operation in which the vapors '.rom the reimA p operation are passed successively through a series of separate vapor condensing` chainbers maintained at progressively lower teniperatures and in Which a regulated part olf condensate from chambers oi lower teniperatures is reiiuxed tochambers ol; higher ternperature. y

The present-invention also includes an iinproved operation in which the vaporsironi a pressure still are suecessivell i subjected a reiiuxing operation and a iiraetionating over ation in which the character of the vapors es caping 'from the reliuxing operation to the ractionating operation is' contr(v i n by u return vof condensate from the trac operation into direct contact with tl in the relluxing operation. i

The present invention also includes au improved reluxing operation in which a 1glurality ol separ ate nactions are separately iiitroduced into direct Contact vvi'lh ie vapors subjected te the reluxing oirieral'ion, and l a pressure still are progressiv ly subjee the reiluxlno' action oi? a pre g. ly lighter Iractions successively introduced lll? into direct Contact with the vapors ifroni the pressure still.

ln carrying out the process of tlie present inyention for the production of gasoline, the

reiiusing operation nay he regulated so that all inate iai Suitable for treatment in thepressure still ina h still for `iti'ii'tlier treatment therein the fractionating operation ina-y he regulated so that such heavier fi actions as niay he desired, or

sucli es are notl suitable or as are notl desi 'ed wine i y e reiiuxed to the pressure lior further treat lent in the pressure still,

roi' example le'osene or the lighter conressure distil1 ete ui desire -h ractiona ine' opere ation, or the finU ig operat'on inau L o regulated to peni soline fraction lo escape and to iy condenserL and collected.

The oil einnlo ed for cooling' and ce i il ing the 1vapors loy indirect heat exch'L the fractioifiating` operation niay lie duced, in Whole or in part, directly into the pressure still, or niay7 in Whole or in part, he introduced into dircf't contact with the va- ;ors underc'oine' fracJ icna'tion in one or more c n 7 of the stages o'i the 'ractionating opertion, or may he directly introduced into the i duz-- ing operation in Whole vor in part. .illiere the resli. oil employed for co lino' and on- L C ii e ctionation contains lighter constituents, suitable as coinponenits of the gasoline product, or oi more or@ the desired products s 'a *l une or eL ted in rsctionsting operation, it may loe introdirectly into the re'l'luxing' operation cooling,l and condensing); the vapors un(erg-'JingY fractionation, and the oil pL i'tially distilled therein, the vaporized cons uents escaping to the rraetionating operation with the vapors from Crude oil, or other ctions or distillate. including' constituents sur `able as components i coi-ninercial gasoline as Well heavier constituents, inay he treated in this insnner to produce a rnei'cl antahle gasoline product in a single combined operution, the lighter constituents being' rsporized in the reir'lufin eperation7 ai""er being preheated by indirect hea exchange in the lractionating,v ope 'ation and subjected to fractionation -Vith the ve roin the reilufiing operation, and the lica* coi stituen'ts introduced into the pre "sure still for cracking, the light r constituents from the pressure distillation heine; subjected to 'the retluxing operation and then escaping' to the fractionating operation With the con stituents Vaporized from 'lie lresli oil in the l'eiluziing operation. A `gasoline oroduct may 'thus be produced directly from crude oil7 or from distillates including constituents boiling over a. Wide range, Without separate fractionation of the material. subjected to the cracking operation and without sepurute re distillation of `lhe cruclred products lroni lhe pressure distillation. Other products7 as niay he desired, may he separated or produced and collected :it the same time.

lvl'here ci pro css oli the present invenlion fied oui' in conjunction wi'ih a pressure (ne illation in a circulatory pressure lsiill. reflux lroin either the i'ei'lufiing operation or die fi'actiouuting operation, and lrcsh cliurg'ini;` stoel( employed for cooli und condensingjv vapors undengoing` fractionation h v inheat cet-:chungo ning', vvilh zulvuul'ufie, inline' srcani oll .s/icl( or (he eonsliliu'nts.

inpoie is oil :inv o'l the i ivi uch, however. :irc :por-

v under the eoiu'lii'ions` prevailing; V4,nire siill and u'hich ure more or tory to cracking` the oil, or .such tus niuy contain such lighter consi iluhe inl'iwiduced into the circulaling oi i or oil enteringr the u' consti l ueni inchino :cone and .s suhjectcd to the cruclc Li yns oi temperature and pressure in die cracking' zone hel'ore any sulislriniiul vu- 'i is ellectc-d7 or during such vapor` here the process of the invcnlion in a single pass cracking silh icl; which has not yet heen euhlluiion may he iuc Yo the lic-sting'elcnieiil'-utcnepoinl e various rel'luxed oils und sepuraled L c fractions returned to the crucliinglreauien inuy he ilitroduced :it other points, as nurv he 'oved :oiarulus is intended :tud :zon-pled und churfinp` out the improved process ol the nventimn and in 'indes various i'ealures ol well-v in its construction and ils zu' fuguvhich will he hereiurjl'ler more,

Vy pointed oui and dcscrihed. iu the zu'conipani'l fi; drawings l here shown certain lornis o l apniralus cnil :odjviug:

illustratiiu 'the invention and in which the process olf Vthe invention can he prac iced. und the invention vvill he liurlher de lcrhed in connection therewith. lt to he under stoodv` however: that these specific illuvlrav lio is and desci'iplion are lor the purpose ol' ,xeinplilicatioin and that the scope oi ihc inveni'ion is defined in che following cluiuls, 'n which I have endeavored to distinguish it lll) llf

,with a hand hole fitting' (t 'from the prior art, without, however, relinquishing;l or abandoning any portionor feature thereof.

ln the accompanyi drawings:

1 is a fracmentary, axial, longitudinal, sectional view or a 'tractionating tower adapted 'for in conjunction with the pressure still and reiiui; tower for carrying out the tra tionating operation ot the process of the invention,

Fig. represents in elevation and partly in section a tractionatinp` tower ot the type shown in Fig. l arranged in conjunction with a pressure still havinpI a reflui: tower thereon, and y f U Fig. 3 represents amodified.arrangement ot the' apparatus illustrated in Big. 2.

Each part is identiiied with the same reterence character wherever it occurs throughthe drawings.

The tractionating tower shown in the drawings is et the general typo described and illustrated in Patent 1,439,420 granted to the Sinclair ldeiiningg` Compalnyi-ipril-S, 1924 on my application. Y j

l'eiterring to the drawin s, tie fractionating` tower comprises a vertical shell 4 closed by end plates 5, each ot which is provided The hand holes are normally closed by plates l and 8. Slightly separated from the end plato 5 at each end et the tower are header sheets 9 and 10, said sheets Yforming with the adjacent end plates, inlet and outlet chambers 11 and 2, for the cooling oil as will presently appear. rilhe space between the leader sheets isv divided into a plurality of vapor condensing. chambers 13, shown as tour in number, although the` number may be va 1ied and is dependent upon the number otscparate fractions or cutsdcsired. i etween adjacent condensing, chambers are chambers 14 tor the cooling` oil, termed by header sheets 15 onopposite sides thereof. The header-sheets are successively con ected by batteries ot' tubes 16 extending through the respective vapor condensing chambers whereby the cooling oil may flow the length of the tower through the successive sets ot' tubes and intermediate chambers. rhe vapor chambers are' provided with suitable baille plates 1'? fitting loosely about the cooling tubes to provide a circuitous circulation tor the vapors therethrough in order that they may be -more thoroughly brought in contact and in heat exchanging relation with the cooling tubes.

A,Fhelowermost `o'tthe vapor condensingr chambers is provided with an inlet port 13 for the entrance of the vapors and the uppern'iost condensing chamber with a vapor outlet 19. Connectioi s 2O are provided to conduct the vapors, or such portion thereof as remains Y' uncondensed, from each vapor chamber.y except the topinost, to the vapor condensing chamber next above, arranged to connect the vseparate vapor condensing chambers, connections are/provider tor controllingl and distributing` the flow oil` cooling oil passing,` through the tubesl on its way to the pressure still through the respective batteries of tubes in the separate vapor condensing chambers. For this purpose, each ot the intermediate cooling fluid chambers 14 is provided with an outlet 31, these outlets being connected to a common bypass pipe 32, the various connections being provided with valves at appropriate points as illustrated.

Each condensing chamber near its bottom and below the level ot the vapor connection thereto has a drawof pipe 23 which is provided at 36 with a gauge glassto indicate the level of the condensate in the chamber and aV valve 37 for shut-ting oil the drawotf and controlling); the passage ot condensate therethrough.' A pipe 38 connected to the gauge glass receptacle extends to a cooler or storage tanlr.- A branch connection 39. leads from the draw-od 23 oi eachl condensing chamber, eX- cept the lowermost to the top of the next lower condensing` chamber at 40, a trap being formed in said pipe at 41' and a valve located herein at 42. A regulated part of the condensate from each condensing chamber may be refluXed through this connection to the next lower and hotter condensing chamber where it is revaporized and returned for further treatment, the amount of reiluX so introduced into the next lower and hotter chamber being` controlled by valve 42. A stream of condensate entering the top of each conder'ising` chamber from pipe 40 spreads over the topmost battle tlierein,'ancl, the holes in bathe through which the cooling,` tubes extend'being somewhat larger than the latter, forms -hlms V'on the tubes until L ing thus effectively subjected 'to the temperature of the tubes. Reiluiicd condensate is thus in effect redistilled and refractionated securing` more denite cut while at the same time effecting regulated condensation of the vapors in the chamber into vwhich it is introduced. y. I

ylhe pressure still shown in the drawingsis oif the'general type described and illustrated in Patent 1,235,200 granted to the Sinclair lleining Company November 19, 1918, on the application ol' Edward Vf. lsom. rllhe process ized be- Cil 3 is made up of the bull; supply tank t3 located away from the heating furnace l-l, the vertical heating tubes l5 arranged in the heating flue 46 of the furnace, and circulating pipes 47, 48 and 49 connecting the lower and upper ends of the vertical tubes with the bull: supply tank and a circulating pump 50 Jor circulating the oil from the bulli supply tank through the vertical tubes and bach to the bull; supply tank. Arranged above the bulli supply tank is a reflux tower 5l havingI a series ot bailles therein and connected with the vapor dome ot the bulk supply tank through the vapor line A return reflux line 53 having a check valve therein to prevent flow into the reflux tower is provided tor the return of reflux to the pressure still. The vapors troni t-he top of the retlux tower escape from the vapor line lo the :tractionating tower 55. rllhe vapors pass upwardly through the fractionating tower, undergoing fractional condensation therein, and any uncondensed vapors and gases escape from the top ot the tower through connection 56. The vapors escaping through connection 56 may be conducted to a separate condenser, or, where they Contain no valuable condensable material, may be conducted to a gas holder.l or may be otherwise disposed of. A connection 57 is provided Ytor supplying cooling oil to the bearings ot' the circulating pump 5G. A continuous tar dr-iwoll is shown at 58 and a pumping out line for discharging the still is shown at 59..

The raotionating tower and the reflux tower, and the various connections carrying hot oil or hot vapors may be suitably insulated to prevent heat loss and to promote the eiicien ey of the operation.' The pressure may be regulated and reduced by means ot' a regulated valve 24 between the reflux tower and the pressure still and the the reflux tower operated at a pressure lower than that prevailing in the still. The reflux tower may also be operated at substantially the pressure prevailing in the still and the pressure in the still and the reflux tower may be regulated and reduced by means of valve 25 between the fractionat-ing tower and the. reflux tower,l and the ractionating tower operated at a pressure lower than that prevailing in the still and relun tower. The pressure may also he regulated and reduced by means of a regulating valve 26 beyond the fractionating tower., or where a separate condenser is employed by the tractionating tower, the pressure may also he regulated and reduced by appropriate valves located beyond thev condenser. rllhe reflux tower and the ractionatingtower, and the separate condenser it one is employee, may be operated at the same pressure or at differentpressures, and at atmospheric pressure or at some intermediate pressure. The reflux tower and the fractionating tower may be operated at substantially still pressure or Lesage-e at some lower pressure, and the lracl'ioiralini;- tower may he operated at the salue pref-sure as the reflux tower or at lower pre-uurs. luterinediate pre es may be tained in the retira`- tout; and in thc l'racin :ilowcr and the lr `sure mav irc pr 'c -iielv rcduced troni re lo :unio-phcrw pre-- sureE or sw e n-lc yrcssurc, as the vapors proceed l'rom the still.

lVhere the retlux tower is operated at .suhstantially the pressure prevuy i' c sure still, reflux may be reti ci. lo ne still from the tower through comic-climi la) lo lhc inlet side oit the cirr .latiirc y, ump (hv opening valves (il and or through cmincctions 65 and GG to the eduction outlet lictweer. the pump and the heatiA ,1; tube:-1 (liy opening valves G2, G3 and til); or where the rcllux tower is operated at a reduced pressure, a pump 68 is provided tor returning rci'lu.: lo the pressure still; either thro 1 connectimi GO (by opening valves Gl, (if), .ll and G3 and closing valve G2.) or through connections (l5 and G6 (by opening valre (Si). ondcnsale from the tractionztiug tower may he introduced into the top or the reflui: lower tlnouph connection Tl, or directlyv intrmluced into the pressure still either through connection ou (by opening valves el, (323 and To) or through connections G5 and Gli (by opening valves o? and 70) by means of pump T2.

Fresh charging stock is circulated through the tubes lll in the iiractionatiugr tower hv means of pump TS. The l ot vapors Vlroin the rollin; tower enter the hottest and lowerinost vapor condensing chamber through connection 5st and pass pwardly through the successive vapor condens; chambers maintained progre@ yely lower temperatures undergoing partial condens tion in cach coudensing chamber. inj." unceudcused vapors or escape from the uppermost and coelest condensing chamber th ough connection 5G. The heavic t vapors are L'uulcnsed in the lowermost a i hottest chamber. the ncJit heaviest vapors in the next hainbcr. and the progressively lighter vapors in the siu'cessive chambers, the condensate in each chamher hc.- ing separately collected n the lower parl: oli

that cnanfiher. The liquid condensate collecting in the lowerinoft chamber nu be returned to the pressure still or to the rellu\V lower through connection T3 or may bc with lrawn. in whole or in partx through valve/l connection We; noconfhnsI follcciingf in lheothcr chr-mbe g ot the series naiv he withdrawn throu'h the valved conne ifluf '-l. )e regulated part ot the condens-:ate collc in cach c iii-ers pt in l1 v be rciiuI-:ed int-fi the nei-1t lower :un holler chandler throw-'h the connections rl. ihr. auiounl ol condensate so returned being controlled in each instance by the valves lf2 in ther coimuuuieating connections.

Freshcharg est cliisalso intrewhucl into Ld ti till lill

lilfl the reflux tower 5l through connection 75. This charging stock may be supplied by means of pump 76 through connection 77, or may be reflux from the fractionatingoperation supplied by pump 72 through connection 7l, or may be preheated stock which has been circulated through the `cooling tubes in the r'ractionating tower supplied through connections71 and 7 9 by pump 7 8.

The charging stool; circulated through the tractionating tower tor cooling` and condensing the vaporsV undergoing fractionation therein may be directly introduced, in whole or in part, into vthe pressure still, after indirect heat exchange with the vapors under- `going fractionation, through connections 7 9, and G6, or may, in whole or in part, be introduced into the reflux tower through connections 7 9, 7l and 75;0'1 all or a part ot the preheatedA charging stock leaving the fractionating tower' through the lower connection 25 may be introduced into one or more oit the Vapor condensing chambers 13 through yalved inlet connections 80, Jfor example, into one or more oit the lower condensing chambers, tor supplementing the cooling and condensation ofthe vapors in the tractionating tower. The fresh oil circulated through the fractionating tower in indirect heat exchange with the vapors therein may, tor example, be introduced directly into the lowermost condensing chamber, and then introduced into the refluxA tower or into the pressure still in admixture with the condensate from the lowermost condensing chamber. The preheated oil thus introduced may also be par-l tially vaporized in the lowermost condensing chamber. Additional oil may also be introduced into the pressure still through connection 66 byl means of pump 81. l

The several pumps 76, 78 and 8l may draw 'from a common supply receptacle, or separate charging'stocls may be introduced, in Varying amount, into the retluxing operation,

through the tractionating operation for cooling and condensing the vapors therein by inldirect heat exchange, and directly into the pressure still, as is most appropriate to the character ot cach` stoclr and 'to the proportionate quantity of the various stocks to be treated.

Fresh ycharging steelt may be-introduced into the retluxing operation independently of that passed through vthe :tractionating operation for cooling and condensing' the vapors by indirect heat exchange, and the retluxing and -tractionating operations may be controlled, within limits, by the respective amounts of fresh stoclr so circulated through the tr ctionating towerA and so introduced into the reflux tower. Where the cooling effected by that part of the feed circulated through the cooling tubes in the tractionating tower is insufficient, additional cooling oil, in addition to that used as charging stock,

may be circulated therethrough and bypassed back t0 the supply receptacle, or a part of the fresh oil circulated through the cooling tubes may be directly introduced into one or more orp the condensing chambers to supplement, by direct contact or by partial Vaporization, the cooling eilected by indirect heat exchange. There the amount o feed introduced into the reflux tower and circulated through the ractionating tower to maintain l the appropriate temperature control ot these two operations is insutlieicnt to maintain the charge in the pressure still, additional and supplemental feed is introduced directly into the pressure still.

There complete condensation is citlected in the fractionating tower 55, or where for any other reason the maximum cooling effect is desired in the tractionating tower 55, all of the charging stock to the pressure still may be circulated through the cooling tubes in the ractionating tower and then introduced into the pressure still, a su'llicient amount ot the fresh preheated stock leaving the lractionating 'tower' through connection 25 being 'introduced directly into the refluxing tower through connection 7 5 to ellect the required retluxing operation therein, the remainder being introduced directly into the pressure still. Reflux condensate from the tractionating tower may also be introduced, in whole or in part, into the reflux 'tower in admixture with t lat part of the preheated stoel: introduced therein, or may be returned to the pressure still directly. f v

`Where separate stocks are being treated, and part of the fresh stock treated contains constituents suitable as components ot one or more ot the linished products, the stocl containing such lighter' constituents is introduced directly into the retlux tower and the lighter constituents are yaporized therein, the resulting 'vapors and uuconden sed vapors from the pressure still passing to the tractionating tower where they are separated and collected in the appropriate fractions. lf the stock containing such lighter components is insutlicient in amount to etl'ect the desired retluxing operation, it i-nay be int`r lucc'd in admixture with other fresh charging stoel; into the rellux tower. llhcre a separate charging stock is employed t'or cooling the tractionating tower by indirect heat exchange, a part ol' this separate charging stock may be aeniixed with the feed to the retlux tower. Stock containi stituents may also be introduced through the tractionating tower, either alone or in admixture with other stocks, before being introduced into the reflux tower.

TWhere a partei the stoel; to be treat-ed include stocks contain' l@ er consti uents which ,vaporize rapidly under the conditions maintained in the pressure st but` which,

such lighter conl Ain the cooling; tubes1 it muy rcticrd the circuany 1groducts oi the utioiu such fresh stocks are introduced ctly into the circustll Where 'they e ope dire hitting oil in the pressure cir ulated through the heating elements l fore being` permitted to escono 'freni t lllhere c, 9 L through the cooling tubes in the lriictionuting' tower su t ien in'tro'tuced ingo the cirr i culuting line of the still.

Rollin; condensate 'troni the trzictionaiting tower, or fresh feed :of e. correspmidingj chairzicter, he directly introduced into the rcili Xing' op notionr either alone, or with other feed7 for regulating und controlling the reduring' operation und limitingl the boiling' range of the fraction es il y c c Jing' troni the retl niing operation to trie frictionuting operotion. Hoei/ier con iensutes collected in the ifrzictionating' tower ine-y lso oe introduced into the circuliting line et the pressure still to insure their subjection to tlie crzcling` conditions o' teiniinerature und pressure insintziiued in the heating element) or they muy oe Withdrawn seperately treated.

l*NF-cere zi large port et the stoel; 'to loe trented includes constituents; suitable as components of any of the desired products the fresh stoel; muy he circulated through the iiructionzitin@tower in indirect heat interchringing reist-ion with the vapors thereii und is then introduced directlj.7 into the reflux tower Where the lighter constituents suituhle es components of any of the products of the ope ation are vapor-ized und escape with the vapors trein the retluiiing operation to the irzict'ionat' g operation. Additional stock muy be circulated chrough the coolingl Vtubes in the frectionating tower :ind by@ ssed buck tothe supply to increase the co' g eilfect therein, and additional feed muy e iiiroduced into tl e relluring tower in iid-unixure with the nrelieeted stock leiiing fraction: touv r through connection 2 to increase the reiiuing elleet el" the prehiuted oil introduced into the reflux toner rroin the i'i :ictionetiig tower.

t any substzrtiul par@ of the oil oir iliited ough the rec-ionsting tourer for cooling` and condensing the Vrij-pers 'frein the redux; i l Vunorizcd n'itlu tower on the pressure st lation or Otherwise decrease c ire heut cxchenpe in the tower. ry.

the steen 'ought into ini zl 1 Ae with the vapors in the uitirgg toner contains lighter constituents, the circulation is regulated so that no subs l i i' such constituents are v'sporiz t tAV igniest temperature to which the Yfresh oil is pr or more of the heavier con moselle hearted in the tower. Vupori'lcction muy :ilso he inlnlntcd hy incrcnirffw L.: upon the tresh chore" quired to torce tubes into the excess of the stil inented und increzrscd in the outle lfroin thc ce lillhere Vit is hesircd to tulicioli r uinount o" tillzitc 'lfrezn the orf as vapors i 'i'uri meer. :i

\, vf, n n. pin. or tn, olemovil @u cooling ui y ors undergroing iti-(ict f i i Mci' here; enchere-e is intrcf unf, udlilionul i the .still JSC. c rcciif 1n Aill. 'llio leli iuzlf lie increased. und con return to the iizitcd port or" one vites sclmrutcd in the iictioiintingr operation.

rci'iuv is introduced into direct coiizici with the vapors undergoing;- reluxn e; :rid this purposeA` u series oiv inlets Yfor the du".- introducti i ot oil muy he provided :is r'rhovfn ere illustrated und in this uur o1 ut the process oli the inreutioii. `l

iiiction introduced rito the redux,

' coi 'L i introduced through tl e. next lighter 'fractie lower connection 823 :inc the tion through che lvottoui con Three sepan-rite inlets :irc Villust wx, inlets or :i greuter iunnher of inlets employed.

lllhere the feed employed lor cooling! :uid condensing` the 'minors unzlero'oiuii fractionntion indirect heut exclu o." :t licglit character, or contains :i sulistun iol :iuiount ol lighter constituents, it muy lie introduced into the. reilux tower thi-or i the connwtionsv if), 'il a id 82, und retin); ,Y nu the 'ruciiwuzting tov-cer introdi ced 'through counecz' ions 1723.y S5 und fr rv heavier 'feed nuit he inro- Clucel .rougyli conuc-z'- n li 1 liv incluis of pump "KG "li is. .x1-)p ,Y i* 'M i it. Y f: rented contains (i su )sonnen uiuoun., or lighter constituenty but u; ius-iuiicieui in Q znnount to ellect the nccessurif' cooling in the rzictioinitingv towerT it muy. llc introducol into the reflux l'r'ure thi-ou; i councctiow TT und 82, und reliux lroui the iti-:iciimuxiuoj tower muy he intromiced tliroufrli conoce tions 85 :ind 8S. life-crier 1; @di noch ozulili) vapors arevcondensc'd in the reflux tower 5l by heat exchange with the fresh feed, which may be of a` gas oil character, introduced into the upper end of the tower and are .returned to the pressure. stillfor further treatment together with the unvaporized part of the feed introduced into the reflux tower. The vapors escaping from the reflux tower through connection 54 comprise the gasoline component, kerosene character frac-tions, and some heavier vapors. The gasoline fraction, together with the heavier fractions, may be separately condensed in the fractionating tower. 55, or the fractionating tower 55 may be operated so as to separate the heavier components from the gasoline frac-tion and the gasolinefraction may be withdrawn from the fractionating tower tlnrough connection 56 as afvapor and conducted to a separate condenser.

Where the gasoline fraction is condensed in the fractionating tower, the gasoline may be condensed in t-he upper two chambers, the kerosene condensed in the next to the bottom chamber, and the heavier fractions: condensed in the lowest chamber. The kerosene character fractionv may be withdrawn for separate treatment or to be put to other use, and the heavier condensate collected in the bottom chamber may be returned to the cracking operation, either directly to the pressure still or through the reflux tower. W'here t-he gaso? line fraction is separately condensed, `the heavier fractions may be separated into various cuts in the chambers of the fractionating tower, for example,kerosene character fractions may be collected inthe topy two or t-he top three chambers and a heavier fraction or fractions collected inthe lower chamber or chambers. rlhe fractions condensed in the 'chambers of the tower'may be marketed as such, or-after further refining treatment; or the different fractions may be blended with each other in a variety of ways according to the specific composition desired. v

Where the desired gasoline fraction is condensed in one or more of the upper condens` ing chambers in the fractionating tower, very close regulation of the gasoline fraction can Y be secured'by returning tothe lower condensber.

Ving chambers a regulated part of the gasoline rthechamber into which it is introduced, and

substantially reduces the amount, if any, of vapors escaping to the linal condensing chamber of a character substantially heavier than f the reiiuxed gasoline fraction. The pressure still and fractionating tower can be operated inthis way for the direct production of a marketable gasoline fraction without redistillation of the pressure distillate. `Where a containing separate condenser for the final gasoline fraction is employed, a similar effect can be secured by returning to one or more of the upper condensing chambers in the fractionating tower a part of the final gasoline fraction collected in the separate condenser.

'lhe process of the present invention may be employed for the direct treatment 'of a crude oil, or .of a distillate containing gasoline character constituents, for the production of gasoline in a single combined operation of high eiiiciency. The crude gasoline material may be 'circulated through the fractionating tower in indirect heat exchanging relation with the vapors therein at a rate and under pressure suflicient to prevent substantial vaporizationand-thereby preheated, the vapors from the still at the same time being fractionally condensed the heat of the vapors being employed, for

preheating the fresh charging stock andfor effecting a further fractionation of the condcnsates, thereby eliminating the step of redistillationof the crude pressure distillate, while at the same time returning the heat in the vapors from the pressure still to the pressure still where it can be employedy in the useful part of the cracking process. r[he preheated crude material may then be introduced directly into the reflux tower and the gasoline character constituents separated Aby vaporization, the introduced oil promoting the reuxing operation both by its sensible heat and bythe heat of vaporization of the lighter constituents, and the lunvaporized part of the fresh charging stock introduce into the reflux tower together with the reflux from the reflux towerintroduced into the pressure still for cracking treatment. F or regulating the operation, part of the fresh oil circulated through the fractionating tower in indirect heat exchanging relation with the vapors undergoing fractionation may be introduced directly into the pressure still,'or additional fresh oil may be introduced into the reflux tower in admixture with the preheated fresh oil from the fractionating tower.

rlhe process of the present invention may Vbe combined with a pressure 'distillation where tar is drawn off from the pressure still during the progress of the operation, and particularly where duri-ng the latter part of the pressure distillation tar is withdrawn in relatively large amount, and where fresh oil is introduced, to maintain the concentration of tai-ry constituents below an objectionable point during ther progress of the operation; In such a combined operation, fresh charging stock, in an amount correspondingto the condensed fractions withdrawn from the .opera- VtionY and any vapors withdrawn from thev fractionating tower, may be introduced into the pressure still through the fractionating tower in indirect heatexrchange with thefvapors therein and then directly into there flux tower; and any additional. feed required for maintaining the stilleharge approximatcly constant as tar' is Withdrawn niay be introduced into thestill directly7 or in part directly' and in part into the reflux tower, or in part tlirougrh the fractionating,Y toiver into the still or into the re'tlur: tower.

lt will be apparent that in one aspect this invention provides an improved operation, which, substitined for the customary li; al condensation of the vapors discharged from the reflux tower on a pressure still, etl'ects a sepa ation of the vapors into the desired fractions directly as they eonie from the pressure still. Without redistillation, and in which the heat usually lost in eondensing` and redistilling the pressure distillate is conserved by employingl fresh charging stoet: on its Way to the pressure still for cooling` and cendensing the vapors undergoing fraeti nation ane by employing the hot vapors undergoinyfractional condensation for preheating the fresh charging` stoel: so employed before introduction into the still. e

lt will also he seen that the present invern tion provides an ii-nproved pro :ess in which the heat of the vapors from the pressure still may be employed for effecting an initial separation of fresh chargingr stoel; subjected to the process by distilling froni the fresh charging stock the lighter constituents suitable as components of the finished product or produets before such constituents are subjected to the cracking` operation proper,

@ne of the important advantages of 'the invention is the elimination or reduction in amount of redistillation of crude pressure distillate and the heat economy effected by einploying` the heat of the vapors frein the pressure still for preheatii g the feed and for efee-ting an improved fractionation of the Crude pressure distillate. Another iinportant advantage of the invention is its tleibility and itsl adaptability of the treatment of a Wide range of materials and its ability to inalre use, to ad Yantage, of several charging stocks of different characteristics.

I elaine:

l. The improvement in the operation of pressure stills for erailring' hyd rocurton oils and dist-illates, which comprises suhjectircb`- the'vapors from the still to a retluxingj operation in a zone separate troni the vaporizine' Zone in direct Contact Vith fresh eliargjine` stock to the still,1 returningthe reflux Vand unvaporized cl'iargfing steelt introduced into the retluxing operation to that. por ion ol' the still stoel; Which is to be immediately s jeeted to high temperature, subjecting' th vapors troni the retlu-Xing operation to a fractional condensation in :indirect heat ef'- changing relation with frzsh charging stoel: and introducing` the'fresh charging stoel; so

preheated directly to the pressure still..

2. Vlhe improvement the operation of cra clzii pressure stills lor nf lrvdroczn'hon fh und distillates, nhrch ein L)rises suhjccling i u the vapors 'troni the still to a rclluxing operation in a :Lone separate l'roin the vaporixinn Zone in direct contact with l'rcsh chargingr stoel; to the stilh returning: the rclux and unvaporized charging .socic introrinccil into thc retluxing' operation to that portion ol the still stock which is to he innncdiatcly suhjceted to high temperature. snhjcrting tlc from the rotluxingg opcration to a 'ondersution in indircf.:` heat cX- rclation with fresh charging stock. ueing a part of the fresh charging" stock in the fra itional eoinlensatimi directly into the relluziiuer operation, and introduring` another part of the charging stock employed in the fractional condensation lireetly to the pressure still.

he iniprorenient in the operation ol' pressure stills for e aching h vdrocarhon oils` and disi'illates, which comprises suhjcclinpV the vapors from the s 'll to a relluxinlej operation in a zone sepa 'ate troni the vuporizine` zone and tuen to a 'fractional coiulcnsatiou in indiriet heat exchanp'irp` relation with fresh chargingstoel: to the still, rcgynhitinn ai eine' the relluxingy operation by intrmlucinp near the point of discharge of the vapors from the reflux operation part. of the heavier condensate condensed in the 'fractional condensation. and intieducirgpreheated stock .fx-(un ,t E

he fractional condor sation directly to the ie still.

ihe iinproveinent in the operation cl pressure stills for crackingv hydrocarbon oils and dist'llates, which eon'ijuises subjeciin; the vapors from the still to a retiuxinfr operation in a Zone sen irate from the vaporizingl t Zone in direct crut with l'resh charging stock to the still, returning the reflux and nnvaporized chin-ring stock introdiu'cd into the retiuxing` operation to that portion ot' thc still stock which is to be inu'nediatelj;y suhj-eeted to higl'i tenu'ieratnre. passingr the vapors freni the relhiirg' operation successiveljvv through a series or :parate vapor con- (lensing` chambers inantaincd at progressively lower temperature, passing' fresh char" Y stock to the still in indirect heat interfharre'in-g;V relation with the vaprn's in the condensing c1 i rclluxiun a part mnihcrs ol'v lower i namhcrs. oi' the (.'ondcn'sate troni h u" highcr lcnipcricatcd churning tcirricruture to chain f l hanihersl directly e l atuie au-d introducing p stoel: freni the condcnsin i' to t 1e pressure still.

'lhe iinproven'ient in the operation oi pressure ftilts for cracking' lrvdrocarhon oils hates. which eonip e? suliijeetingr the vapors fron-'i a pressure l to u relluxina "inw-rtree in a sti one separano from the vaporn :cone and returning the relur; to that po on of the still stock which is to he i1n1nc- ,Tut L. bfH/l w j Y." .1 t). .n .t y. onaeij su perd o ingu telupc (.tiue, passing the vapors from the refluxing operation successively through Va series of, separate vapor condensing chambers maintained at progressively lower temperature, passing fresh charging stock to the still in indirect heat interchanging relation' with the vapors in the condensing chambers, reuxing a part of the condensate from chambers of lower temperature to chambers of higher temperature, and introducing rpreheated charging stock from the condensing chambers directly to the still. j

6. The-improvement in the operation of pressure stills for cracking hydrocarbon oils and distillates, which comprises subjecting the vapors from the still to a refluxing operation ina zone separate from the vaporizing zone in direct contact with fresh charging stock to the still, returning the reflux and unvaporized charging stock introduced into the refluxing operation to the still, subjecting the vapors from the refluxing operation to a fractional condensation in indirect heat exchanging relation with fresh charging stock vto the still, regulating the refluxing operation by introducing near the point of discharge of the vapors from the refluxing operation a regulated part of the heavier condensate in the fractional condensation, and introducing preheated charging stock from the fractional condensation directly to the pressure still.

7. The improvement in the operation of pressure stills for cracking hydrocarbon oils and distillates, which comprises subjecting the vapors from the still to a refluxing operation in a zone separate from the vaporizing zone, subjecting the vapors from the refluxing operation to a fractional condensation in indirect heat exchanging relation with fresh charging stock to the still, whereby the vapors are condensed andthe fresh charging stock is preheated, further fractionating part of the fractional condensates so produced by vaporization in direct contact with fresh hot vapors from the reflux tower,

and introducing preheated charging stock from the fractional condensation directly to the pressure still.

8. In combination, a pressure still, a reflux tower, and a fractional condenser, connections for conducting vapors from the still to the i'eflux tower and for returning reflux to the still, connections for conducting vapors from the reflux tower to the fractional condenser, means for bringing fresh charging stock to the still in heat interclianging relation withthe vapors in the fractional condenser and connections for introducing charging stock from said last named means directly into the pressure still.

9. In combination, a pressure still, a' reflux tower separate from the still and a fractionating tower, connectionsfor conducting vapors from the still to the reflux tower and separate connections for returning reflux to the still, connections for'conducting vapors from the refluxtowerrto the fractionating tower, means for passing fresh charging stock to the still indirect contact with the vapors --in the reflux tower, means in the fractionatnections for conducting vapors from the still to the reflux tower and for returning reflux to the still, connections for conducting vapors from the reflux tower to the fractional condenser, means for bringing fresh charging' stock tothe still in heat interchanging relation with the vapors in the fractional condenser, connections for introducing charging stock from said last named means into the pressure still, and means forY Withdrawing from the fractional condenser at least two fractions.

11. In combination, a pressure still, a reflux tower and a fractional condenser, connections for conducting vapors from the still to the reflux tower and for returning reflux to the still, connections for conducting vapors from the reflux tower to the fractional condenser, means for bringing fresh charging stock to the still in indirect heat exchanging relation with the vapors in the fractional condenser and connections for conducting fresh charging stock from said last named means to the still, means for introducing heavier condensate from the fractional condenser into direct contact With the vapors in the reflux tower near the upper end thereof, and means for introducing relatively heavier stock into direct contact with the vapors in the reflux tower at an intermediate point.

12. In combination, a pressure still, a reflux tower separate from the still and a fractional condenser comprising a series yof condensing chambers adapted to be maintained at progressively lower temperatures, connections for conducting vapors from the still to the reflux tower and for returning reflux therefrom to the still, connections for conducting vapors froin the reflux tower to the fractional condenser, means for bringing fresh charging stock to the rstill in indirect heat exchanging relation with the vapors in the fractional condenser, connections for conducting fresh charging stock from said last named means to the still and means for refluxing part of the condensate formed in the fractional condenser from chambers of lower temperature to chambers of highei` temperature.

131.. In combination, a pressure Still, a rolnx toaWo-r sopzrrzite from the Still and :i fructionalf condenser oonyrprising a, serios of condensing chambers adapted to be maintained :it progressively lower temperatures, connections. for conduct-.ing vapors from the still to the renx tower, means for introducing; fresh charging stock into direct Contact with the vapors in the reflux tower and for returning reflux and said changing stock thorofrorn .to the still, connections for Conducting vapors frointho reflux tower to the fraction- ;il cumlcilsoig :nouns Vlor bringing); l'rwll hurging Stock lio llio slill in iudirvrl lwnl Qm'lmllgjing rolzil'ion with rllz vapors in il v 'rxuiionnl (-onrlvnfor, Comnfiirms i'm vomlnuling; lrosll Charging' Sl'ovk 'rmn Smid lnwl numeri moans lo ho still through thv rmaix www :nul moans for rolluxingr puri' o lllc conrloiirmlc formed in Uw fractional comlcnror il'roni Chambers* of lower lrnlwrzi'uro lo vlnunlf-vrs oli higher tcni'perziluro.

ln tostiinonjv nlwroolt l :ilix my signa uw.

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