US1867136A - Method of absorption - Google Patents

Description

July 12, 1932. 1 A CAMPBELL 1,867,136

METHOD OF ABSORPTION I Original Filed Deo. 17. 1927 3 Sheets-Sheet l July l2, 1932. A CAMPB-ELL 1,567,136 METHOD OF- ABSORPTION Original Filed DSG. -l'7. 1927 5 Sheets-Sheet 2 July 12, 1932 J. A. CAMPBELL 1,867,136

METHOD OF ABSORPTION l .Original Filed De. 17. 192'? 3 Sheets-Sheet 3 Patented July 12, 1932 NETED y STATES JULIANacAMrBELL, or vLone BEACH, CALIFORNIA METHOD or A Bsorarrion Application led December 17, 1927, Serial No. 240,742. Renewed Januaryl, 1932.

This invention has to do with methods for transferring vapor between liquids and gases. Such methods arel used, and the method of this present invention is capable of use, in absorption systems, or in stills, dephlegmators, and the like. In any such method or process, whether the immediate object is to take vapor out oftheliquid, or to absorbl vapors into a liquid out of gas, the 1o general underlying function is one in principle; that is, to establish a condition of equilibrium between vapors and liquids, under the operating' conditions maintained. Consequently, the method herein described is capable of use either in absorption systems or in distilling or dephlegmating systems; in fact, the major object of this invention, that of bringing liquids and gases into very finely divided and intimate contact with eachother, applies equally well to Vall such systems. However, the inventionis largely usedv in absorption systems, so,u for that reason, and also Vbecause the invention will `Vbe readily understood in that connection,` I explain the invention here as applied lto absorption, and particularly absorption of low boiling point vapors, such as gasolene, which are carried in natural gas.

The method which is the subject matter of the present invention has some similarity to other methods which are subjects ofco-pending applications filed by me. In my application Serial No. 18d,870, filed April 19, 1927, entitled Method of absorption, I set out a method characterized bythe formation of a mass of froth in which a. gas and liquid are brought into intimate contact and subsequent. ly separated by breaking up the froth. Then, in `my prior application, Serial No. 123,417,

filed July 19, 1926, I have set out an apparatus and method wherein'a mass of froth is first formed in a chamber between two perforated plates, the mass of froth being then forced through the upper perforated plate, by whose action the froth is rendered completely uniform, the froth mass building up above'the upper perforated plate and being finally broken up at` a level above lthat upper plate. In both these prior methods the. intimate contact is obtained between'the liquids and gases within the masses of froth, the breaking of the froth resulting in the direct formation of a body of separated liquid. In contradistinction to that method, or as an additive functional l step, the present method first forms a mass of fine and uniform froth, ob- Y taining intimate contact in such froth form; but then, in the present method, this froth is broken up in such a manner that the liquids and gases are notmerely separated as before,

but so that the liquids are-'broken up into f very line particles in anatinosphere of the gas. The froth thus notonly serves inthe first instanceas a means of obtaining; intimate contact, but also serves to get the liquid into the form of thin films, from which l.form 1 the liquid is'easilyand effectivelybrolren up into very fine particleswhich-form aline mist in the gaseous atmosphere and obtaina'most highly intimate contact between the: liquid and gas. I-Iow all of this is done will now be bestunderstood from the following detailed specification wherein I explain first a suitable apparatus and'then explain'theimethod as carried on lin this apparatus. Itawill be l understood that the method is not necessarily limited to performance in the particular apparatus described,.but as this apparatus includes the necessary characteristics and features for carrying on the method, and further, forms a simple, e'ective apparatus for that purpose, I shall describe the apparatus in detail. One of the apparatus features which, as far as `now seen, is necessary for carryingV on the method, is this: That the froth be broken up into mist at a. level above which either any unbroken froth or ,coalescing liquid (resulting from separation of liquid and gas outof froth) may accumulate. That is, where the formed froth'is specili- 99 cally blown Vthrough the upper perforated plate, it is blown upwardly directly into an atmosphere` of gas, and not blown upwardly into a mass of froth or a body of liquid.V The p apparatus hereinafter described `provides the '95 necessary physical feature for thestatedop-` eration. It will be understood, however, that the apparatus itself is not made the subjectmatter of theV claims herein, the apparatus being claimed in a co-pending application, Serial No. 240,741, filed on even date herewith and entitled Absorber (which matured into Patent No. 1,748,409 issued Feb. 25, 1930).l VSuch apparatus is illustrated in the accompanying drawings, in which Fig. 1 is a .fragmentary vertical central section of the absorber;

Figs. 2, 3, 4a1id 5 are horizontal cross-sec-V tions taken respectively on lines 2-2, 3 3,

Fig. 6 is a perspective of one of the'inner 13 whichV acts to 'operatea valve controllingy theliquidoutlet -(not shown,as it has no bearing on the present invention). N ear the bottom of the Vshellvfthere is an internal ring 15 having an upstanding inner flange 16that forms an annular liquid holding channel around.- the periphery off the shell, for the y purpose ofvforming a'liquid's'eal at a point Where the liquid/is finally discharged into the bottom part of theshell, all as will hereinafter appear.'v rl`his ring 15 alsor forms the supporting shelf which supports the several inner shell j sections and the c several superposed floors.-

Briefly described, the shell and floor structure is; made upV of a series of outer shell sec-v tions land 20a`and yaseries. of inner shell sections 21, 21a and 2lb; with perforated I floors 22 and 23, and an uppermost perforate floor 24, supportedV and spaced by the several Yshell sections. The floors Aare preferably supported and spaced so that they areV located in pairs, 22 and 23. Theouter shell sections 20 and '20a are all iinperforate, their function being merely toA form an outer shell wall for thefpassages which are located between such outer shell walliand rthe inner shell wall formed of sections 21 and 21a. Op- `eratively :and functionally the outer shell sections 20 and 20may be regarded as Vthe outer wall of the double shell structure herein referred to, the outermost continuous shell 10 being provided only for the purpose of making the apparatus pressure-tight as a whole. Or the outermost continuous shell 10 may be looked upon as theouter shell of c the ldouble Walled structure, the outer shell sections 20 being provided merely to make a wall, outside of which the assembly bolts V may be passed. Itis convenient tofrun'those assemblybolts through the edges of the sev eral floors, to hold the Whole structure in aligned position, and itis alsofconvenient to have the several floors extend their edges outwardly past th-e outer shell sections 20,

20a, as thereby certain perforations in the i several floors, registering with the spaces between the shell sections, maybe utilized for controlling andr directing the flow of liquid.

And it is convenient to have the assembly bolts pass through the several floors outsideY of the operating space between thedouble walls, as thereby it is not necessary to make tight joints where the bolts pass through theV several floors. Consequently, in a preferred structure, in accordance with the present invention, the several floors 22 and 23 are of such diameters as to fit fairly snugly'into the outermost main shell 10. The edges of'these floors, outside the shell sections 20, 'have notches 25 which pass the vertical assembly bolts 26, and the outer shell sections 20, 20a` tubes 29, compress the -whole assembly tightly in a vertical direction andmake sufficiently fluid-tight joints between the several floors andthe edgesof Vthe several shell sections.

.Eachfshell section 21 isprovided with openn ings' 35 near its lower edge, the .openings eX- tending around approximately half of the periphery. ,',Each section has .a plurality of `spacer ribs 36 which do not extend tothe lower edge of the section, and two oppcsitely disposed spacer ribs 37 which extend from top to bottom of the section. All the spacer Yribs engage at their outer edges withthe corresponding outer shell section 2O and serve to maintain the two concentric shell sections in proper relative position, and the two ribs 37 serve additionally to separate half of the annular space between the shell sections `from the other half of said annular space. And the relative arrangement of opening and ribs is such that all of the openings 35 lie in one of the half circumferences between the two ribs 37 and therefore communicate with only one ofthe half-annular spaces between the concentric shell sections. Y

. v The construction of the shell section 21e is similar with openings 35a and ribs 36a fand 37a, the only difference between 4sections 21 and 21a being amatter of height. Y

. Eachiipper floor 23'has one or more lraised perforated surfaces 43. In the particular design here shown theseraised perforated surfaces 43 are formed as circular 'perforated plated plates raised on circular rims 44 above the surface offloor 23, each formation 43,

a perforated top. These inverted pans are spacedV apart from eachother as shown in the various views so as to allow a oonsiderable space around the pans lfor separated liq'- uid to collect on the floor 23, the liquid collecting until it reaches a height sufficient to iiow out through the openings 35. Each floor 23 also has peripherally arranged perforations 45 extending around its'complete periphery and in such positions as to register with the annular space between the two concentric shell sections 20,' 21 and V20a to 21a. Each lower floor 22 is preferably perforated over its entire-surface within the circle ofthe shell section 21a, and outside the circle of that shell section 21a it has perforations 46 extending around half of its vperiphery only, these perforations registering with a halfannular space between the shell sections 20, 21, and 20a, 21a. The several floors 22 and 23 and the several shell sections 20, 21', 20a and 21a are all of identic construction, but are assembled in such a manneras to control and direct the flow of liquids as will now be described. rlhe uppermost inner shell section 215 may be identic in structure with shell section 21, but is invertechso that its openings 355 come near its upper edge rather than near vitslower edge. Y

In operation as an absorber it will be understood the rich gas is fed under pressure into the lower end of shell 10, the gas passin@ upwardly through the several floors, and the denudedgas finally passing ofi' through the'gas outlet 50 at the top. At the same time, absorbing oil is being introduced through a suitable oil inlet, such Vas indicated at 51,-the oil feeding through perforated distribution pipe 51a out over the uppermost perforated floor 24 andrising, as froth, to a level where the oil from broken froth overflows through openings 355 of shell section 350 of shell section 215. Flowing through these openings the oil flows into a half annular space between shell section 215 and a corresponding concentric section 20, being restricted to that half annular space by the two ribs 37. The uppermost Hoor 24 has a semi-circular series of perforations 46a similar to the perforations 46 of iioors 22 5 and the oil flows downwardly through these perforations 46a into the half annular space A immediately below and between the next lower shell sections 21 and 20. 'An absorber'constructed in accor-dance with lmy. invention may contain any suitable number of fioor sets; but for the purpose of euplanationflll will suppose that the upper set shown in Fig. l and in Fig. 8 is the uppermost set of the absorber. VThus, the oil will first flow down through the half annular space A between shell sections 20 and 21, at the righthand side of; Figs. land 8, andfthence the oil will flow through the perforations 45 of floor 23 into the half lannular space B between shell sections 20a and 21a'and between floors 22 and 23. Thence the oil will flow directly through openings 35a into the space C inside shell section'21a and between the two floors 22 and 23. Here the oil, spreading out over floor 22, is picked up by the gas passing Vup through that perforated floor and a mass of froth is formed, this mass. of froth rising and Vfilling the inverted pans 43, 44 untilthe froth is forced up 'throughthe perforations v inV plates l43.` The vcompara-tive aggregate perforations areas of fioors 22 and 2 3 are preferably such that the velocities throughA the perforations are about equal. Forinstance, in an average case, the lower floor 22 has perforations 5/32` diameter on 1^ spacings. The plates 43 of the upperY floor have holes of the same diameter but on vhalf-inch spacings. The total area of plates 43' is about half of the total area of a floor 22; so

that the aggregate perforation area of an upper floor 23 is about twice the aggregate perforation area of the lower ioor 22. But

words, the first action at the upper plate perforations may be considered tobe tomake the froth more uniform', as a `preliminary to Vdisrupting the froth and atomizing the oil.

The velocity through the perforations-#the expansion of the gas above the perfora- Ations-breaks up the froth bubbles and forms the oil into an exceedingly fine mist floating in the gas above the upper floor. This mist falls through the gas, the collecting liquid flowing .down belowthe pan tops to collectv on the floor 23 around the pans. Thence the il flows out throughtheopenings 35 at the `left-hand side of shell section 21 into the half annular space D V(see'Fig. 8) between that shell sectionv and shell section 20. Here the oil flows down through floor perforations 45, through' space F between shell sections 200; 'and 21a and floors 23 and 22, and thence the oil'flows throughthe floor'perforations 46 at the left-hand side of floor 22 and into and through the half-annular space A1 be- `tween the next lower shell sectionsV 20'and 21. Halfeannular space A1 is the same as half-annular space A except that it is ar.

ranged at the opposite side of the assembly. rI he 'oil'flows directly'downwardly through space A1 and on down through floor perforation 45 into the left-hand half-annularspace roo B1 between theV next'lower shell sections 20a and21a.V Here theV oil, stopped from further downward flow .by part 22a of floor 22, flows again throughv openings a which, in Ythis shell section 21a, are arranged' at the left of the apparatus as shown in thedrawings, the oil flowing into the circular space C1 inside shell 20a between floors 22 and 23'. The, oil ishere again'subjected to the action ofthe Aupwardly flowing gas, the froth rising and being forced ythrough perforated plates 43,.

VThis space A2 is an exact counterpart, bothv in structureand position, with the first mentioned half-annular space A; and the flow of the. yoil from here on down through the apparatus is repetitions of the flow know fully described. VUpon leaving the last andlowermostk floor set, the oil will pass through the openings 35, suchas those shownV at the lower leftV side of Fig. Yl,V and, passing through perforations and 46 in those lowermost floors,

.'willpas's'thence into spaceV F (see Fig. l

at the lower left) outside the lowermost shell section 2l. Thencethe oil passes through openings 35`in thatl lowermost shell section 2l, voverthe seal. flange 16, and drops down -into the .body of oil'which normally stands in the bottom of shell 10. This final passageV of the oil is indicated bythe arrows at' the lowerleft-hand side of Fig. l.

The oil being formed into a fine inist above each floor, falls out of the gas rather slowly. Consequently, in operatingat reasonable gas flow velocity a certain amountv of the inist,

but not a large proportion, is carried up with the gas through the next perforated floor 22 where it is merely caught by and merged in the froth being formed there. To prevent any oil mist being carried out ofthe apparatus above th'euppermost floor 23 I have provided the uppermost perforated floor 24y (which is like floor 22. but without any associated floor The incoming oil isfirst distributed in a thin layer over floor .24. The Ygas rises through that layer, forming Vand raising a mass of froth whose level rises to the lower edges "of openings 355. rAt the upper .froth surface, and at the opening edges which arey preferably sharp, the froth breaks up, vfreeing the gas to pass on up and' outoutlet as substantially7 dry gas, the

yfreed oil flowing through` openings 355 to pass .down throughthe apparatus.

.From the foregoingv description of operation of the various apparatus features, it will now be understood how the oil lis substantially all formed into a froth with the gas in a space immediately above a perforated floor 22. It will be noted that the oil is delivered horizontally overthefloor 22, being introduced to the floorl at its edge and spreading out overthe floor more or less in the form of a thin filmer layer. Gas passing up through this thin oil layer forms the mass of froth which, in full operation, fills the space between the two perforated floors Vof a set. And the fact that the .oil isdelivered to the bottom of this mass of froth. (rather than, .for

instance, being delivered by dropping downV through the froth mass.) prevents the inflowing oil from breaking upv the froth mass.v

The result is thus the continuous formation and vbuilding upof Va mass of froth,.from below, at the perforated floor plate 22. This mass of frothis, above anyselectedfloor plate, under a. certain, maintained pressure, due to the initial introduction of the laden gas under pressure at thebottom of the absorber.V Under this pressure this massof`V froth is forced up through the perforations in the raised plate 43 of the upper floor 23.

Atv the perforations of plate 43 there is avcertain drop of pressure, resulting in a substantial velocity of the froth mass through the perforations. (In, practice, the pressures on the vapparatus are maintained so that, as a typical instance, the drop in pressure at eachperforated plate is about 0.2 pound per square inch.) When thefroth is forced through the upper plate perforations, the'action atand :upper *pla-te.l This action of breakingthe froth bubbles may be looked upon asV due to Vthe velocity of the froth through the upper plate perforations; Y' butv itV is immaterial whetherthe'velocity or the reduced pressure be considered the cause of forth-breaking, as the relativelylower pressure is itself the cause of the velocitymaintained. Y

In the gaseous atmosphere above the upper plate, the froth bubblesy burst, ythe Vthin oil films breaking up'into a multitude of very IDE fine liquid particles-the ,oil becomes atom- 5 ized to a very fine mist.' This -mi'st .more or less floats inthe gaseous atmosphere. VTo a large degree the mist slowly settles and cora- ,n

lesces to Y'form' a liquid body of oilwhich accumulates on the floor 23 below the level of plates Also any slight amount of froth 1. i; body of froth by passing a vapor laden gas up dition of operation.

froth bubble-Elms into line particles,

which may remain unbroken after passage through the upper perforations accumulates at a level below the raised plates 43; so that neither the accumulated oil or froth interfere with the froth atomizing action. Thus, the froth atomizing action goes on unimpeded, the very fine atomized particles of oil more or less floating, or slowly sinking, in the gaseous atmosphere, and the coalesced liquid flowing olf from the described lower level and thence down to the next pair of plates in the apparatus. This coalescedliquidbodyhas been found in practice to be substantially free of gas, which is a highly desirable con- The liquid mist, however, is so fine that not all of its settles out of the gaseous atmosphere abovethe upper perforated floor, a small part of it being carried on up through the next perforated floor and into the next frothing action. i This upward carriage of mist is not objectionable except at a point above the uppermost floor, where it is taken care of as has been before described.

I claim:

l. The method. that includes first forming a froth of a liquid and a vapor laden gas, at a selected pressure, then expanding the froth in an atmosphere of the gas at a comparatively less pressure and thereby breaking the there being an abrupt pressure change between the pressure atl which the froth is formed and the pressure of the gaseous atmosphere in which the froth is broken up, and allowing the fine liquid particles to settle in the gaseous atmosphere and to coalesce into a body of liquid out. of contact with the froth being introduced into the gaseous atmosphere.

2. rEhe method that includes forming a through a perforated plate over which an absorbing liquid is introduced, building up the froth body by continuing such formation and forcing the froth body by pressure up through another perforated plate and directly into an atmosphere of gas thereabove and at a relatively lower pressure, and thereby breaking the froth Vfilms into fine particles, allowing the particles to settle in the gaseous atmosphere to form a liquid body, out of contact with the froth being introduced to the gaseous atmosphere, and withdrawing liquid from the liquid body.

3. The method of causing intimate contact between a gas and a liquid, that rst forming a froth of the gas and liquid, reducing such froth to substantial uniformity in which substantially all the liquid and gas are frothed, allowing to expand and break into Ene liquid particles in an'atmosphere of the gas, and then coalescing said liquid particles and separating Jhe resultant liquid from both the gas and the rot 4. The method of causing intimate contact includes i the froth-bubble-lms between a gas and a liquid, that includes first forming a froth of the gas and liquid at any certain pressure, reducing such froth to substantial uniformity in which substantially all the liquid and gas are frothed, allowing the froth bubbles to expand and break into fine liquid particles in an atmosphere of the gas at comparatively less pressure, and then coalescing the liquid particles into a body of liquidV introduced into the gaseous atmosphere.

5. The method that includes first forming a vertical series of lfroth bodies comprising a liquid and a vapor laden gas at selected pressures, thenexanding each of the froth bodies into atmospheres of the gas at comparatively less pressures' and thereby breaking the froth bubble-films into ne particles, there being abrupt pressure changes between the pressures at which the froth bodiesare formed and the pressures of the gaseous atmospheres in which the froth bodies are broken up, -al- Y lowing the fine liquid particles released from the froth bodies to settle in the gaseous atmospheres and to coalesce Vinto bodies of liquid, and delivering each of the liquid bodies formed by the coalesced particles to the froth body next below to be reconverted into froth.

6. The method that includes forming a vertical series of froth bodies by passing vapor laden gas up through vertically spaced perforated plates over which absorbing liquid is introduced, building up froth bodies on said plates by continuing such formation and forcing the froth bodies by press-ure up out of contact withthe froth being through other perforated plates and directly v into atmospheres of gas thereabove at relatively lower pressures, the froth films into fine particles, allowing the particles to settle in the gaseous atmospheres and to coalesce into liquid bodies, and delivering each of the liquid bodies formed by the coalesced particles to the froth body next below to be reconverted into froth.

In witness that I claim the foregoing I have hereunto subscribed my name November, 1927.

JULIAN A. CAMPBELL.

this 28 day of and thereby breaking

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