US2646266A - Multiple flow column - Google Patents

Description

July 21, 1953 D. c. LOCKWOOD 2,646,266

MULTIPLE FLOW COLUMN Filed March 22, 1948 v 4 Shee ts-Sheet 1 IN V EN TOR.

I7770ENEVS' y 21, 1953 o. c. LOCKWOOD 2,646,266

MULTIPLE FLOW COLUMN 4 Shee'tsw-Sheet 2 Filed March 22, 1948 JNVENTOR.

July 21,1953 v D. c. LOCKWOOD MULTIPLE FLOW COLUMN 4 Sheets-Sheet 3 Filed March 22 i948 I n Q I 0 &

RTTOBNE' July 21, 1953 o. c. LOCKWOOD MULTIPLE FLOW comm 4 Sheets-Sheet 4 Filed March 22, 1948 Patented July 21, 1953 MULTIrL FLOW- COLUMN I w 7 I I i Daniel 0. Lockwood, soumra'saiiena, casing; F signor to C. F Braun & (20., Alhambra, Calif., acorporation oi California, 1 Application March .22, 1948,.SerialNo..16,302

This invention relates to liquid-vapor contact apparatus and is particularly directed to improvements in vessels or columns of the type used for contacting an ascending column of vapor v with a descending stream of liquid. such vessels are commonly employed in connection with chemical'processing apparatus, This invention will be described in connection with a vacuum flasher column of the type now employedin the refining of petroleum and petroleum products, but it is to be understood that'the invention is not limited to this particular embodiment or use.

' Conventional columns employing vertically spaced staggered splash decks or vertically spaced circular baffles of the disk and doughnut type are well known inthe art, but only a. single'liquid curtain is provided betweenadjacent splash decks or, bafiles. Sucharrangements have been found to beflsatisfactory for small and medium diarneter vessels, but on very. large diameter vessels the required vertical spacing between decks or bafiies is so'great that theoverall height of the column becomes excessive. The'vertical spacing is determined by the required areas for properfiow of the ascending .vapor.

roam. ((11. 2615- 114) invention; and employing-;vertically spaced splash decks.

Figure 6 is a sectional plan view taken ,stantiallyon the lines 6v6 as shown in- Figure 5;.

Figure 7 is a view similanto;Figure 6 taken substantially on lines l las shown in Figure 5. cFigur'e- 8 is a-diagramma-tical sectional eleyationof a-modified form of column structure em b dyi my in -m ,-Fi r 9 is a'i onal plan, i Wl-t ke b:

stantially on lines 9-59 as shown'in Figure 8;

-Figurel0 is a View similar to'F-igure 9 taken substantially on lines. llk-lll-as shown in Fig--' Figure 11- is asectional elevation'ofa'portion of a column structure andshowing a, preferred In accordance with this invention a multiple I flow of liquid in a plurality of separate liquid splash decks or baffles, with the result that sufficient passage area for -ascending vapor is --pro-- vided to permit much closer spacing of the splash I decks or baifies, and therefore the-overall height of the column may besubstantially reduced.

, Accordingly, it is the principal object of this; invention to. provide a novel form of liquid-vapor contact vessel of high efiiciency and substantially I reducedoverall height. I v

1 Another "object is to provide a newand improved splash deck assemblyadapted to produce a plurality of liquid curtains :between adjacentlevels of splash decks. V

, Other objects and advantages will appear hereinafter. 1 6 v I In the drawings; Figures 1 to 4 illustratediagrammatically conventional forms of liquid-vapor contact apparatus. Figure 1 is a sectional elevation showing a conventional splash deck arrange-.

Y curtains is provided between adjacent levels of v ment. Figure 2 is asectional view taken sub-- stantially on lines 2-2 as shownin Figure 1. r V

Figure 3 is a sectional elevation showing a conventional disk anddoughnut baflie arrangement.

Figure 4 is-a sectional plan view taken substantially on lines 44 as shown in Figure 3.

Figure 5 is a diagrammatical sectionalv elevation showing a column structure embodying my embodiment of my invention;

I Figure 12.-is a sectional plan view-taken -sub stantially on lines l2'--I;2.as shown inFigurelL Figure 13 is a viewsimilar to Figure-'12 taken substantiallyonylines 13-43 as shown in Fig- Figure 14 is a sectional plan view taken substantially; on lines l4,l4 as shown in Figure 11. Figure 15 is a transverse sec'tional elevation showing details of construction of a preferred form of; splash-deck embodying my invention 0 Figure 16 is a transverse sectional; view showing details of construction of another formof splash deckembodying'my invention. Referring to'the drawings, the conventionalf-orms of liquid-vapor contactcolumns shownin Figures l-Atol employ verticallyspacedbaffles over which allow of liquid occurs. As the liquid falls by gravity from a-bafile on one level to a baiiie atalower levela liquid curtainis provided,-

and ascending vapors are passed through these liquid curtains in" order toachievethe-desired liquid-vapor contact. I

As shown in Figure 1' the shell IIJ' provides. a

closed vessel having an outlet H for vapor atits upper end, anoutlet' l2 forliquid at its lower end, an inlet I3 for liquid near its upperendand an inlet [4 fora vapor liquid mixture. Vertically spaced splash decks 15, I6 and I7. are

mounted within the shell I8 in staggered 'rela tion. Liquid admitted through the inlet l 3vflows over the outer edge E8 of the upper splash deck l5. and fallsin the form of a liquid curtainll to the next lower splash deck [6. Similarly, liquid,

onthe splash" deck l6 falls over its outer edge 20 in the form of a liquid curtain-2| down to the lower splash deck 1 1.; Ascending vapors admitted into ,the shell by way o f the inlet I4 must pass through liquid curtains 2| and I9 in order to reach the vapor outlet II.

If desired, a liquid collector trough 22 may be mounted within the shell at a location to receive the liquid falling from the lower splash deck ll. Liquid in the trough may be withdrawn through piping (not shown) and if desired may be recirculated through the upper liquid inlet [3. The vertical spacing between the splash decks is proportioned with respect to the width of the horizontal opening at each level so that the passage areas for vapor remain substantially equal, or so that the passage areas are proportioned in a predetermined relationship; Thus the area of the liquid curtains I9 and 2 bis made substantially equal to the area of the horizontal openings between the edges 18 and 20 and the The path of adjacent wall of the column ID. the ascending vapors is diagrammatically illustrated by the arrows 23.

In the conventional apparatus shown in Figure 3 the shell [a provides a closed vesselhaving outlets Ila, [2a, and inlets I311; 14a, similar to those just described in connection with Figure 1. Instead of segment shaped staggeredsplash decks, baflles in the form "of disks 25 and doughnuts 26 and 21 may be provided in vertically spaced relationship; These disks and doughnuts may be supported in any conventional manner as, for instance, by brackets fastened to the shell wall. The disks 25- are preferably circular and imperforate, while the doughnuts are annular in form and are provided with a central opening.- Liquid admitted into the shell via the inlet- [30 falls from the doughnut 26 in the form of a circular liquid curtain'28 and-impinges'on the disk 25. The liquidthen falls from the outer perimeter on thedisk in the form of a circular liquid curtain 29. Vapors admitted into the shell Illa viathe inlet 14w must pass through the circular liquid curtains 29- and 213 inorderto reach the vapor outlet Ila provided at the top of the shell (0a.

If desired a collector ring 30 may be-supported within the shell and positioned under the circular liquid curtain 3| falling from the central aperture in the doughnut 21. Piping (not shown) may be provided for withdrawing the liquid from the shell la, and if desired'such liquid maybe recirculated through the inlet. Ma." The vertical spacing between disksand doughnuts is proportioned with respect to the areas of the annular openings around the disks and to the central openings in thedoug'hnuts in a manner such that-the passage areas for ascending vapors are maintained substantially equal. The path of'the ascending vapors is diagrammatically illustrated by the arrows 32.

It will be noted that in the conventional type columns shown in Figures 1 and3 a single sheet of liquid or liquid curtain is present at each.

the overall height of the column becomes exces-' sive. The use of catalytic cracking units in the refining of petroleum requires very large'amounts of feed stock of the type provided by liquidvapor contact columns of the type disclosed herein. The required capacities are solarge that the cost of conventional columns of the type shown in Figures 1 and 3 becomes prohibitive.

In accordance with my invention, I provide a multiple or divided fiow of liquid in a plurality of separate liquid curtains between adjacent levels of splash decks or baffles, and in this manner secure sufficient passage area for ascending vapors while utilizing much closer spacing of the splash decks or baflles. of the column may be thus substantially reduced. As illustrated diagrammatically in the preferred embodiment shown in Figures 5 to 7, I provide a plurality of splash decks at each level within acolumn, and the vertical spacing between levels is substantially reduced since multiple passages for ascending vapors and multiple liquid curtains are provided between each level. Thus,

:the shell 40 provides a closed vessel having a vapor outlet 4| near its upper end, a liquid outlet '42 nearits lower end, a liquid inlet 43, and an inlet 44 for vapor liquid mixture.

Parallel splash decks 45 and 46 extend transversely across the column and define a horizontal space 41 therebetween and horizontal spaces 48 and 49 between thesplash decks and the walls of the column 40i- Four separate spaced liquid curtains 50 are formed along the parallel edges of the splash decks 45 and 46; Liquid is directed onto the upper surfaces of the splash decks 45 and 46 from distributor pipes 51 and 52 supplied from the common inlet 43; The liquid curtains 50 fall on three transversely extending splash decks 45 and 46 and accordingly need not be further described. The liquid curtains 6lfallingfrom the splash decks 59' and 60 may be intercepted by collector troughs 62/63 and 64-if desired, and the liquid maybe withdrawn from the shell through piping (not shown).

divided on the upper surface of the splash decks 45 and 46, curtains'are provided between adjacent levels.

These multiple curtains provide sufficient passage: area to enable the vertical spacing between levels to be substantially reduced without impairing the efiiciency'of the column.

In themodified form of my'invention' illus tratedin Figures 8 to 10, disk and doughnut baiiles aresused instead of the splash deckabrangementshown in Figures 5 to 'l. The shell 40a, outlets Ma and 42a, and inlets 43a and 44d, together with the distributor pipes 5Ia and-52a, may be substantially the same as those described inconnection with Figures 5 to 7.- Liquid directed against the upper surface of the annular ring or doughnut 10 flowsdownwardly fromthe inner and outer peripheries thereof in the form of two circular concentric liquid curtains H and l2.

l3 and the central disk 14. Concentric liquid curtains l5 and-l5 extend downwardly from the outer periphery of the disk 14 and the inner opening-inthe doughnut 13' respectively.-- An annular ring or doughnut 11 intercept-s bothof the concentric liquid'curtains 15 and 16" in a manner'simil'ar to that described above; concentric circular liquid curtains l8 and 19 extend downwardly from the central opening in the doughnut TI and its outer periphery respectively.

The overall height The liquid may be recirculated through the inlet 43. It will be observed that the downward flow of liquid is and thereafter multiple liquid Theseliquid curtains impinge on doughnut.

The liquid falling, fromthe doughnutfI'I may-be.- collected in the collector. rings 80. and; 8| if. de.--

sired, andthelliquid may; be withdrawn from the vessel through piping. (not shown) If ,de.-' sired, such liquid may: be recirculated. through inlet 43a; It will be observed that multiple paths; forvapor are provided-through. the pair of concentric circular liquid curtains provided'between each level ofbaffl'es. Accordinglv'the vertical.

spacing between baffles may be'reduced withoutimpairing the efficiencyof the column, and-the overall height of the column may, be reduced; "r

In Figures 11 .to 1.6 I. have .shown' a preferred embodiment of my, inventionwin considerable. detail.- Splash decks'are illustrated instead of disks and doughnuts, isince it has been:,found; that the contact areas forliquidand vapor .can.

be kept more :uniform in this manner. Distribu clined splash decks I03 and I04 to provide a support therefor. It willv be observedthat the supporting structure for thes'plash decks 93 and 94' is positioned remotely from the upturned edges I05 and I06 and from the liquid curtains extending downwardly therefrom in'order that theefiective passage areas through theliquid the end area of the openings 96:-and1-9'I bear a tor pipes '90 may be supplied with liquid'fromfa single or separate inlets (not shown), .and these. distributor pipes 90 extend horizontally; across. the interior of, the column shell- 9I- above a distributor trough 92 provided on each ofthe splash decks generally designated 93 and 94. The splash decks 93' and 94- extend transversely; across the shell inparallel' relation. and. define a. space 95 between their adjacent parallel edges andspaces 96 and 97 between theshorter-edges ofthe disks and theinterior of the wall ofthe shell 91. The

distributor troughs 92 each include a longitudinal horizontal plate 98 having upturned parallel edges 99. Uprlght stiffener plates I extendrate streams; "These streams flow in opposite directions over the inclined deck plates I03 and I04; An upturned lip'l05 -and'I06 is provided along the outeredge of each of theinclined'deck plates I93 and I04 respectively.

A "series of apertures I01 and I08 may be formed along the outer edge of each inclined deck plate adjacent its upturned lip. Liquid curtains may not be decreased.-

i In order to provide a substantially. equal liquid vapor contactfthe widths of the splash decks 93 and '94 are so proportioned with respect to the widthsof the openings 95, 96 and 9I.that

relation to the area of the opening 95 whichis equalto the relation between the length of.;the' short side I06 of the splash decksandthe length of the-long side I05..

, .The inclined deck measles maybe bolted to.

the cantilever supports I20. The construction issuch' that the beam 1, cantilever supports I20, inclined splash decksI03 and I04, and asso-:,f

ciated parts maybe withdrawn from the column. when desired for the purposes of cleaning or' inspection. The openings in the column, ends are made-sufficiently large to accommodate the largest single removable'piece.

7 The four liquid curtainsv I09, I I and H2- extending downwardly from the splash decks;;.93 and 94' impinge on the splash decks; I I4, ,II-1and 30,:

H6. I The splash deck II5 may be substantially v identical tothe splash :decks 93 and-94 described above, with the exception that theweirplates IEII v f are omitted. The side splash decks II4.Iand 11s fiows downwardly through said apertures I01 and I08 in the form of a rain to provide liquid curtains I09 and I I0 extending downwardly from the edges of the splash deck93, and to provide liquid curtains III and H2 flowing downwardly from the edges of the splash deck 94. Suitable structure II3 may be provided for supporting the distributor pipes 90 on the splash decks 931 and 94. I

Supporting structure for thesplash decks 93 and 94 is provided within the column 9|, and

this structure is positioned and proportioned so that a minimum of restriction is imposed upon the upward flow of vapors from the spacesbetween the splash decks II4, H5 and H6 on the next lower level. As shown in Figures 12 and 15 this supporting. structure preferably comprisesa central beam II'I which may be bent from a single sheet to form a rectangular box section and joined to the horizontal plate 98 by any convenient means, such as for example spot welding. The central beam II'I extends longitudinally under the horizontal deck plate 98 and may be bolted to end supports I I8 fixed within the wall of the shell 9|. F1anges II9 may be welded to the beam Ill at spaced intervals, andcantilever trusses I may be bolted to these flanges II9 and extend outwardly under themdecks 93 and 94, except that the weir plates I9I are each .bolted to'an annular horizontal ring I50 .v'velded to the :interior of the shell 9]. .Stifiener ribs. I5I are bolted to supportplates. I52 secured to the interior of'the shell ,9I.. at circumferen-j tially spaced intervals. Tnedeck plates I22 may be I positioned substantially horizontally and :PlO-

vided with an upturned lip IZI. ,It will;be observed that the splashdecks I I4 and; I I6 are each comprised of .a plurality .of individual-qsections,

each having an. upturned ,lip I2I anda 'pairoi,

spaced side stiffeners I5I. The lip 'I2I extends inwardly underthe upper splash deck 93, 94, and

a series of apertures I22a may be provided in the deck plates I22 adjacent the lip I2I. Liquidon the splash deck passes through the apertures I22a in the form of a rain or'liquid curtain I23,

The liquid curtains I23 and I24 falling from the side splash decks H4 and H6, and the liquid curtains I25 and I26 falling from the splash deck H5 impinge on the splash decks I21 and I28 which are substantially identical to the splash are omitted. Accordingly, liquid on the splash decks I21 and I29 falls in four separate liquid curtains I29, I39, I3I and I32. The liquid in the latter said curtains may be collected within the shell 9| if desired and recirculated into the distributor pipes 90. As shown in Figures 11 and 14, side collector basins I33 and I34 are provided for intercepting the liquid curtains I29 and I32. A central collector pan I35 receives the liquid from the curtains I30 and I3I. Any convenient or desired construction may be employed for such. collector basins, and such preferably includes removable bottoms I39 mounted on transversely extending beams I31. The be'ams I31 may be bolted to end supports I39 fixed within the shell 9I. Suitable piping (not shown) may be provided for withdrawing liquid from the shell 9I'.

The upper edges of the upturned lips I05 and I06 of the splash decks 93, 94,- II5, I21 and I28 aemsea may-be notched if desired along their. entire length order to form weirsfor uniform 'distria bution of fluid 'alongi the-length: of the splash decks Should the aper-tures: illt andulflB adjacent the: lips becomeplugged zand cease :to: tune-1 tion properly; thenotches alongthe upper: edges: of. the lips function to provideliquidzcurtains- In a similar manner the upturned dips-.121: on the side splash decks :I I4 and. H5 may be. also notched-along their upper length tot-provideweird-Failure of the apertures l22-"to function properly would then permit fluid-to flowcver theweirsin uniform curtain"; The de'ckplat'es 1'03 and .Hldrasshown in Figure: 15 are-oppositely inclined-to direct liquid through the. apertures: lfll and 108 or. over thewlips. I05 and N16. The inclination of the deck plates 1103.- and HM is highly desirable for colinnnsxwhielsi are. to operate at .relativelyrhi'gh temperature; since: in

' such cases it'is desirable tokeepthe liquidrmov ingat arelatively higharfiowzrateaandvto avoid any slu'ggishness': in flow.- 'By* this means objec-- tionable coking on the trays. prevented or mini+ mizedr For columns'which operateat lower 136121?" peratures, however, the cokingiproblemuis not troublesome, and accordingly; the: decks 83- and H14 may be placed substantially horizontal if desired.

Having fully described my' inventiomit is to be understood that I do not wish to be. limited to the details herein set forth, but myginvention is of the full scope of the appended claim;

I claim:

In a vessel of the class described for contactin an ascending column of vapor with a descending stream of liquid,'the combination of-z'a shell; a first transverse splash decl; including a horizontal beam extending transverselyacross the shell and being removably fastenedto the walls thereof, a distributor trough mounted along the upper face of said beam, cantilever support plates fastened to and extending laterally from both sides of said beam at spaced intervals therealong, said cantilever r plates being- :tapered with the widest end fastened to said beam, 2. pair of: oppositely inclined decmplatesearried on and overlying said cantilever plates andsloping downwardly away from 'saidabeampinner' edges of said deck plates underlyingrltheouteredges of said trough, thev deck: platesqeachbeing provided with an upturned. lipxalongits lower edge, a second transversesplash. deck'similar to said firstsplash deck positionedbelowsaid first splash deck and spaced laterally: thereiromso that one of said lips of the upper splash deck: overlies onehof the: deck plates" of-said second: splash deck, a thirdtransverse splash decksimilar. to. said first splash deck positioned similarly:- to said: second splash deck so that theiother of saidrlips -of: said first splash deck overlieson'e oi the deck plates of said. third splash deck,' said onecf theilips o'nsaid first splash deck cooperating with: the lip-onsaid one deck plate'of said-second splash vdeck towd'efine the-edges of a first passageway for ascending vaporythe other of said lipson saidfirst splash. deck cooperating with the lip on said one deck plate on saidxthird splash: deck to define the edges- 0f a second passageway forascending vapor, said beam. associated with said first splash deck being remote from the' edges-of-1both the first and second passageways toprovide maximum unobstructed passage area for ascending-vapor.

DANIEL CILOCKWOOD.

I Nuinber Name Date 423,906- Haskin-- Mar. 18,1890 991,970 Gamble May 9, 1911 1,146,861 ,Fowlerw..-e July 20, 1915 1,632,397. Fluor. s- June 14, 1927 2,051,545 Collins- Aug. 18, 1936' 2,210,808 Glitsch Aug. 6,.1940 2,242,727 Meyer May 20, 19 1 1 2,558,222 Parkinson e ..e June. 26,.

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