US1489420A - Fractionating tower for pressure stills and the like - Google Patents

Description

April 8 1924. 1,489,420

J. E. BELL FRAGTIONATING TOWER FOR PRESSURE STILLS AND THE LIKE Filed July 8. 1921 2 Sheets-Sheet l 1 a i 2, i 6

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J. E. BELL FRACTIONATING TOWER FOR PRESSURE STILLS AND THE LIKE 1921 2 Sheets-Sheet 2 Filed July 8 lllllllll lulllll citizen of the United States, residin nrrao STATES rArsNr Terrier.

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A CQRQOBATION OF MAINE.

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-Be it known t atl, JOHN E. Berna at Brooklyn, in the county of Kings and tate; of New York, have invented certain new and useful Improvements in Fractionating Towers for Pressure Stills and the like of which the following is a specification.

In the process of cracking gas oil and the like to make gasoline, the condensate from .the pressure still contains in addition to the lighter hydrocarbons suitable as cornponents of the gasoline, hydrocarbons of the.

'lrerosene group and others evenheavier. lit

is therefore necessary. to sub]? densate to redistillation to ect' the con-' ractionate it into merchantable products and to separate out the heavierhydrocarbons. It is the 'purpose of the resent inventionto partially or entirely dispenseiwith this redistillation by tractionally condensing the vapors as they come from'the pressure still, separating the kerosene traction and the heavier compounds from the gasoline vapors and separately condensing them. Forthis purpose ll employ'a fractionating 'cendensing tower whichhas a series of vapor condens- Ting chambers through which the vapors vfrom the pressure still travel successively ontheir'wa'yto the final condenser tor the.

' .gasolinedraction The condensing surfaces in the" successive chambers are maintained at successivelylower temperatures so that the heaviest vapors. are condensed inthe 192 1. senn' No. man.

to sacrifice accuracy ordefinit'enes's in cut to some extent to ractical considerations: In my improved specific example thereof shown in the drawing and hereinafter described, the, cooling oil: or other cooling medium enters the condensing tubes of the last or coolest condensing chamber at a temperature Within de grees of that ofthe vapors leaving the chamber the temperature of the condensmg surt ace beingsomewhat intermediate the temperatures of the oil and vapors respectively. Furthermore" the temperature of'the oil leaving the tubes of the first condensing chamber is within 25 degrees of that of the vapors entering the chamber, and this temperature difierential is substannssr'enoa are smcmra'nnrmme com? ractionat-ing tower, in the:

tially maintained throughout the condense ing chambersof the tower. If desired the differential could be reduced to say. 1 0 do grees but this would vastly increasethe size of the apparatus, if the same cuts were to I ture difi'erential, supposing the vapors comingfrom" the still. to retain a temperature to gasolinefraction with a 25 degree temperaf of say 530 degrees when they reach the tower "the oil tor' coolingthe condensing tubeswould enter at a temperature of say degrees'and leave at a. temperature of about'505 degrees. By increasing theflow of cool oil; or'decreasing its'initialtempera- I "hire greater condensation could befac'hieved a next heaviest vapors in the second cham= I-but. at the expense of 'definiteness-of out.

r The nearer the ternperature'of the condensing surface approaches the critical temperature Qfthe'va or-tO be condensedthemore accurate" is .theTtractionation; a d theoretically .it would .be desirablethat the;

' surfaces be m'aintained at temperatures a .few degrees only below the critica-l'tempera- 'tures of the respective vapors to be con-'- I .-dens'ed. 0bviously', howeventhisjwould he" with each'other' or with stock'from 'other impracticable because of the large number of'compounds of different avities'in the! vapors to be condensed-an .the greater tent. of condensing surface necessary for;

eachj-.;vvher'e such a low temperature difi'er--;1 nt'ial is maintained. I it is necessary therefore a condenser to which-it is led from the tower Preferably the gasoline fraction is not con-' dens'ed 'in my; tractionating tower. but in and which may beof' usual or approved four condensing sections or chambers the 'firsticut, condensed inthe first or hottest 's'ectionwould' containneither gasoline nor kerosene and inight be returned to the still or put in heavier stock} {lhe next three cuts'wouldbe kerosene andjcould' be mar-' helped as such or. the different cuts blended sources in a variety of ways according to the specific composition des1re d.-vv If no '95 ."torrri; Thus; for example, with a tower of kerosene is'desired the towerimay be operated with-a smaller dropin temperature of sane and heavier fractions coulol bereturned the cooling---oil in the device. The kerbfrom the first two chambers of the fractionating tower to the still and gasoline condensed in the other two chambers. Any cooling fluid, stable at the temperatures to which itwould be subjected, might be employed but preferably I use a suitable 011 which is constantly circulated through the tower, preferably in a direction opposite to that of the vapors, and through a cooler to absorb the heat from the oil and back to the tower by means of a suitable pump. In order to increase the efiioien'cy of separation I may reflux all or any portion of the cpndensate from any or all of the condensmg chambers, except the first or hottest, into the chamber of next higher temperature.

For this purpose the tower is preferably vertical, as in the construction shown in the drawings, the series of vapor condensing chambers being super osed therein and the vapors entering at t e bottom of the series and leaving from the top thereof. Condensate refluxed from an up er, cooler chamber to a lower, hotter c amber is mainly revaporized in the latter a small fraction only of heavier components, which have been carried over with the lighter vapors remaining behind in liquid form in the hotter chamber.

In the accompanying drawings I have shown a preferred embodiment of my invention and described the same in the following specification. It is to be understood, however, that the specific disclosure is for the purpose of exemplification only and that the scope of the invention is defined in the following claims in which I have endeavored to distinguish it from the prior art so far as known to me, without, however, relinquishing or abandoning any portion or feature thereof. i

In the accompanying drawings Fig. 1 is a side elevation of an apparatus embod ing a preferred form of my invention; Fig. 2 is an axial longitudinal sectional view of the same on an enlarged scale, partly broken away; Figs. 3 and 4 elevations partly in section of details, and Fig.- 5 a horizontal section showing a detail.

Each part is identified by the same reference character wherever it. occurs. in the views.

In the preferred form of invention shown in the drawing the fractionating condensing tower comprises a cylindrical shell 4 closed by end plates 55, each of which is provided with a hand-hole fittin 6. The hand-holes are normally closed y plates 78. Slightly spaced from the end plates 5 at each end of the tower is a header sheet 9, 10, said sheets formin with the adjacent end plates inlet and out et chambers 11, 12 for the cooling fluid as will presently appear. The space between the header sheets is divided into a plurality of vapor condensing chambers 13 shown as four in number, though, the number is optional and dependent upon the number of cuts desired. Between adjacent vapor condensing chambers are chambers 14 for the cooling fluid which chambers are formed by header sheets 15 on opposite sides thereof and. the wall of the cylindrical tower, and the header sheets are connected by batteries of tubes 16 extending through the respective vapor condensing chambers, whereby the cooling fluid may flow the length of the tower through the cooling fiuid chambers and said tubes. Preferably 'the vapor chambers are provided with suitable battle plates 17 to provide a circuitous circulation for the vapors therethrough in order that they may be- As best shown in Figs. 2' and 3 this by -pam is formed of rectangular tubing, .the end flanges 21 of which are secured in any suitable manner to the cylindrical wall of the tower above and below the intermediate cooling fluid chamber.

Preferably oil is vthe coolin fluid employed as heretofore stated and it is preferably circulated downwardly through the tower and is drawn off at the bottom, cooled and returned to the top of the tower. For this purpose a cooler 24 is connected by ipe 25 to cover plate 7 of the lower manholia 6, the other end of the cooler being connected by a pipe 26 to circulating pump 27 by which the oil is forced through pipe 28 to the top of the tower. It has not been considered necessary to illustrate in detail the cooler .24 as it may be of the usual tubular construction, the inlet for the water or other fluid for cooling the oil being shown at 29 and the outlet therefor at 30, Fig. 1. In order to properly control thegravities of the several cuts efi'ected in the respective vapor condensing chambers, I have provided for ing fluid through the respective batteries of pipes in said chambers. For this purpose each of the intermediate cooling fluid chammeans of this by-pass pipeomore or. less of the cooling fluid may be by-passed about any of the vapor condensing chambers ex cept the first or it may be carried any controlling and distributing the flow of coolof the cooling fluid chambers directly to the cooler. In order to kee the temperature conditions under close servation each of the vapor connections 'is formed with a thermometerrwell 35.

Each condensing chamber near its bottom has a drawofi' pipe 23, which is provided at the cooling tubes extend bei 36 with a gauge glass to indicate the level of the condensate in the chamber, and a valve 37 for shutting off the draw-0i! and controlling the passage 'of condensate therethrough. A pipe 38 connected to the gauge glass extends to a cooler or storage tank. A; branch connection 39 leads from the draw-0d '23 of each condensing chamber next lower condensing chamber at 40, a trap being formed in said pipe at 41 and a valve located therein at 42. By means of this connection the condensate from each condensing chamber may be refluxed to the next lower and hotter condensing clram-.

her where it will be revaporized and returned for further treatment, the amount of the reflux being controlled by valve 42.

lhe stream of condensate entering the .top of the condensing chamber from. pipe 39 spreads over the topmost baffle therein that my invention provides a compact and economical apparatus in which the vapors coming from the still can be divided mto cuts as desired, the division between the several cuts being definite and under the operators control, thus dispensing with the ex ensive operation of redistillation.

claim: 1. In a fractionating tower for pressure stills and the like, an elongated shell, headers in the respective ends of said shell forming. liquid chambers, circulating means receiving liquid from one of said headers and conveyin it to the other, intermediate pairs of hea ers forming liquid chambers in said shell and dividing the same into vapor chambers, batteries of tubes extending through said vapor chambers and connecting the adjacent headers, ducts connecting adjacent vapor chambers, a vapor inlet to one of the end vapor chambers, a

' vapor outlet from the other end vapor chambeer; and condensate draw-oils ineach of said vapor chambers.

2. In a fractionating tower for pressure stills and the like, an elongated shell, head are in the respective ends of said shell form- 'cuitous path. I (except the lowermost) to the top of the I ing liquid chambers, circulating means receiving. liquid'from one of said headers and conveyin' it to the other, intermediate pairs othea ers forming-liquid chambers in said, shell and dividing the same into vapor chambel'abatteries of tubesextending through said va or chambers and con-,

pectin the adjacent eaders, ducts connecting a jacent vapor chambers, a vapor inlet to' one of the end vapor chambers, a vapor outlet from the other end vapor chamber, condensatc-draw-ofis in each of said vapor chambers and bafiles in said vapor chambers to cause the vapors therein to pursue a cir- 3. in a tractionating tower, a shell, end headers at the respective ends of the shell, forming end liquid chambers, intermediate headers forming liquid chambers and dividing the shell into a series of vapor chambers batteries of tubes connecting adjacent headers and extending through the vapor chambers, by-pass ducts connecting the vaporchambers outside of said shell, a vapor inlet to one of the and vapor chambers, a vapor outlet from the other end vapor chamber, and condensate draw-ods from the respective vapor chambers.

' 4. In a fractionating tower the shell, end headers at the respective ends of the shell, forming end liquid cham'bers, intermediate headers forming liquid chambers and dividing the shell into a series of vapor chambers, batteries of tubes extending through the vapor chambers and connecting the headers at the ends thereof, connections between the vapor chambers, a vapor inlet to one of the end vapor chambers, a vapor outlet from the other end vapor chamber, condensate draw-eds from the respective vapor chambers, aheat interchanger for cooling the cooling liquid a connection from said. heat interchanger to one of the end liquid chambers and, a pump connect% to the heat interchanger and to the. other end vapor chamber.

5. In a rractionating'tower, a shell, end headers at the respective ends of the shell forming end liquid chambers, intermediate headers forming liquid chambers and di viding the shell into a series of vapor cham ber batteries of tubes connecting adjacent headers and extending through the vapor chambers, ducts connecting the vapor chambers, a vapor inlet to one of the end vapor chambers, a vapor outlet from the other end' vapor chamber, condensate draw-ofl's from the respective vapor chambers, a byas pipe, connections from the intermediate iqui chambers to said by-pass pi and valves in said. pipe for controlling te passage of liquid therethrough.

JOHN n. BELL,

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