US2678200A - Apparatus for effecting intimate contact between liquids and gases - Google Patents

Description

F., C. KOCH ET AL APPARATUS FOR May 11, 1954 2,678,200 EFFECTING INTIMATE CONTACT BETWEEN LIQUIDS AND GASES V 3 Sheets-Sheet 1 Filed Nov. 26, 1949 '4 INVENTORS @724 4% q. fiwagag mm H W F. C. KOCH ET AL May 11, 1954 2,678,200 APPARATUS FOR EFFECTING INTIMATE CONTACT BETWEEN LIQUIDS AND GASES 3 Sheets-Sheet 2 Filed Nov. 26, 1949 an. b. I E .010. b I

I l 0 0 0 l O l I O Q I Q I a mv Av a INVENTORi k/ xea/ C W May 11, 1954 F. c. KOCH ET AL 2,678,200 APPARATUS FOR EFFECTING INTIMATE CONTACT BETWEEN LIQUIDS AND GASES Filed Nov. 26, 1949 5 Sheets-Sheet 3 INVENTORS.

Patented May 11,1954

APPARATUS FOR EF CONTACT BETW GASES Fred C. Koch and Hanassignors to Koch En Wichita, Kans, a cor [The present invention relates to improvements in apparatus for effecting intimate contact between liquids and gases. The present invention concerns itself particularly with further inventive improvements in the apparatus disclosed and claimed in the patent to Fred C. Koch, No. 2,401,569, issued June 4, 1946. X It was found that the performance of the apparatus described in the aforementioned Koch patent could beimproved, particularly with respect-to the ability to handle larger volumes of liquids by making certain changes in the position of the various deflecting means and contact plates, and by modifying the down-flow passages, in ways more fully hereinafter explained. Accordingly, it is one ,of the objects of the present invention -to provide efficient contact means for large volumes of liquids and vapors, in a type of device that allows the liquid to course downwardly through the apparatus in cascade fashion, while the vapors pass upwardly in coun tercurrent relationshipwith the liquid.

A further objectof the present invention is to provide means which will counteract the tendency of the liquid to back up, and to flow inunintended directions in the apparatus. A still further object of the present invention is ,to. provide means ,for imparting a greater velocity to the stream of liquid that issues from the bottom of the downcomers in a contact device of the type hereinafter, disclosed, so that more-intimate contact with the rising vapors will be attained.

Other objects of the presentinvention-will become apparent from the further descriptionhereinbelow.

To illustrate the inventionseveral sheets of drawings are filed concurrently herewith, in which the invention is illustrated in a more or less diagrammatic manner, some of the portions thereof being shown; in section, but with no more dew tail than is necessaryfor a proper understand: ing of the inventiomit being understood that the drawings arenot to scale and are not intended as working drawings, but to be merely illustrative of the underlying principles. ,Anyproperly skilled engineer can, design the details of the apparatus in accordance with the inventive concept as more fully explained in connection with the said drawings.

Inthedrawingsy i H, i Fig, l is a mostly diagrammatic, verticalgsec tion through a contact towerfcon'structed in ac- Tb d n eW th he d m a r e r wi the FECTING INTIMATE EEN LIQUIDS AND y Litwin, Wichita, Kans., gineering Company, Inc.,

notation of Kansas Application November 26, 1949, Serial No. 129,678

5 Claims. (01. 261114) Fig. 2 is a cross-sectional view along the line 2-2 of Fig. 1;

Fig. 3 is a vertical section, on an enlarged scale, of a portion of the apparatus as shown in Fig. 2, being taken along the line 33 of said figure;

Fig. 4 is a vertical section through a portion of a seal-pan, on an enlarged scale;

Fig. 5 is a vertical section, also on an enlarged scale, of the preferred construction of the bottom of one of the downcomers; and

Fig. 6 is a vertical section along the line 66 of Fig. 4, showing a detail of construction.

The general construction of the apparatus of the present invention follows that of the already mentioned patent of Fred C. Koch, in that a cascade typeof vapor-liquid contact device is employed. In the present modification, improved operation is attained by providing against the so-called back-flow of liquid, by which is meant the overflow of liquidfrom one of the cascades in a direction opposite to that which Was intended, so that improper vapor-liquid contact would be brought about. Generally speaking, this is accomplished in the present case by providing perforations also in the bottom portions of the vertical plates mentioned in said prior Koch patent, but also in the modification of the downcomers, and in the use of deflection-plates at the bottom thereof, to cause the liquid to change direction as it discharges onto the cascade sections.

The apparatus comprises a vertical housing l2, which may. be of any convenient cross-section, but which is preferably a vertical cylinder in which i the other parts of the apparatus are housed.

Suitably supported in said housing are a plurality of superimposed liquid-vapor-contacting sections, of which there are preferably three in parallel in each section. It will be understood that there may be from 6 to 8 sets of these superimposed, but as they are substantially all alike, only two of them, and theircorresponding sealpans, are shown in Fig. 1. For simplification, thickness of material has been omitted except in connection with housing l2 and a number of supporting parts. i Referring first to the uppermost vapor-liquidcontacting section, broadly designated as A, this will be seen to consist of "three individual parts; all of which are substantially alike. They are supported on a suitable circular support 13 which rests upon a ledge or ledges it that are secured, such as by welding, to the interior of the housing I2. For sake of simplicity we shall describe nary-one of these three parts, namely,

the one on the left of the drawing. It consists, in this particular embodiment, of four cascade lips l5, [5, IT, and I8, which are fed, in this case, from the bottom part of a downcomer l9, which feeds liquid from a superimposed deck (but not shown in the drawing) against the first lip 15. The lip which comprises an upwardly inclined perforated baifie 2!}, also has a downwardly depending imperforate baffle 2 Liquid coming down the downcomer I9 is directed against the perforate baiile it, passes thcrethrough, and sprays out in the left hand side thereof, some of it also falling down over the baffle 26. Vapors arising upwardly, as

shown by the dotted arrows, pass underneath the bottom 22 of the downcomer 1:9 and are deflected downwardly by the bafiie 2|, so, as to pursue a tortuous course around baffle 21 and then again upwardly as indicated by the further dotted arrows. The liquid which is pouring through the perforations of the bafile 20 is thus intercepted by the rising vapors and comes into contact therewith. If large quantities of liquid are employed, the perforations in baffle 20 will prove inadequate and liquid will flow, over the top of baflie 20. r

The division of the downfiowing liquid into fine streams which are directed against the perforated/plate 251 results in the liquid and vapor making a froth which flows across the apparatus. Were the liquid allowed to flow into the trough 23, it would tend to plug it off, increasing the pressure drop and forcing more of the vaporinto the other troughs, thereby lowering the capacity of the apparatus.

Inasmuch .as the bottom of the plate 24 is also perforated some of the liquid will also pass through the perforations therein to" fall downwardly into the next lower cascade tray to be there intercepted by the inrushing vapor in exactly the same manner as has already been explained. 7

Here the performance repeats itself, some of the liquid falling into the lowermost cascade tray 23 to impinge against still another plate 24, likewise provided with perforations, but in this case it falls into the next lower downcomer 19 which is quite wide at the top but gradually becomes narrower as it approaches the bottom so that the discharge end 26 is much narrower, therefore the liquid which would ordinarily be merely freely falling, will tend to become confined t'o a narrower area so that when it falls into the next lower cascade section B, it will be deflected against the first perforated bafile 2i} thereof with considerable force by virtue'of the inwardly bent baffle 21 which is attached immediately to the bottom of the downcomer I9. The wide area at the top of the downflow is to' permit as much of the vapor to separate from the liquid as possible and pass upwardly. When as much vapor has been liberated as possible the downflow is constricted to the velocity of the falling liquid and will sweep whatever vapor has not been separated down with it;

In the next section the operation repeats itself until the liquid falls into the still further downwardly located third downcomer 19, which however in'this case leads to a standpipe 28, the bottom of which is immersed in liquid contained inia, seal-pipe 29 from which latter further downcomers; i9, and presumed to be located belowthelevelof the seal-pipe 29in the housing l2, will be fed inexactly the same man- 'ner' as has already been described in connection withthe uppermost downcomer i9.

The vertical baflle plates 24 are suitably secured to'angle irons 30 which are secured to a supporting plate 3| which latter is supported by means of the aforementioned ring 13 preferably by riveting or welding at the point 32.

' Inasmuchas the other cascade sections shown in the upper deck A and the lower deck B are exactly the same, numbers have been omitted therefrom, as a further description appears unnecessary.

Referring specifically to Fig. 3 which shows the most important portions of the present device in detail, the course of the down-coming liquid has been indicated by solid arrows, while the course of the -up-rushing and intercepting vapors is shown by dotted arrows. It will be seen that by virtueof the force of the contact some of the liquid is hurled upwardly and then passes through the perforations 25 in the upper parts of the plates 2 Inasmuch as considerable amount of the vapor is also rushing upwardly between the plates 24, the dispersed liquid therein will also come into very good contact with the upwardly passing vapors.

The present invention is to be differentiated "from and considered an inventive improvement upon the prior Koch patent, in the utilization of the upwardly directed perforated baffle 20, and in the provision of perforations 25 even in the lower parts of the plates 24;

The further novelty resides in the construction of the downcomers l9 and particularly the utilization of the direction-changing baiiles 21 atthe bottom thereof. V

By superimposing the various sections the decks of which are displaced from the other, a considerably better contact between the gases and the liquids is obtained, and therefore the contacting tower can be used with much greater flow of liquid. 7

With towers of comparable size the amount of run-back which could be handled in a tower constructed in accordance with the aforementioned Koch patent is around 90 gallons per minute per foot of weir. A tower of similar d'imensions but constructed in accordance with the present improvement is capable of handling inexcess of 200 gallons per minute per foot, of weir. Moreover, the present construction allows of a much greater vapor disengaging space above the cascade, all of which makes for better exchange between the vapor and gases on the one hand and the down coming liquid on the other. V

It'will be noticed from Fig. 2 that the central cascade section is considerably more elongated than the two adjacent ones, and that the one on the right in Fig. 2 is the smallest. Inasmuch, however, as the various superimposed sections are reversed at an angle of it will be self evident that a section taken alcngthe line passing through the next higher set of cascade 'por tions would be a mirror image of what is to be seen in Fig. 2. p

In actual practice, liquid is fed to the uppermost downcomer Hi from a suitable source, or it may be materialwhich is condensed in the upper portions of the gas-liquid device of the present invention,-suchliquid coursing downwardly from deck to deck in a manner well understood in this art. 7 l

-Thevapor may be introduced at any suitable pointat or near the bottom of the gas-liquid contact tower, and may be removed from the top of the tower in a manner well known by ducts or. piping, none of which is essential to an understanding of the present invention in view of the high state of development of the dephleg directed baiile 20, which is part of what has been termed the first lip i5, is of great importance. The reasons for this are best appreciated in connection with Figs. 3, 4 and 5. If the baffle were eliminated, then the liquid discharging from the bottom of downcomer l9 would simply flow like a water-fall over the downwardly directed plate 2| so that the up-rushing vapor would have to force its way through the mass of liquid. However, the combination of the bafiie 2'! at the lower end of the downcomer I 9 with the upwardly extending perforated baffie 2|] produces the following valuable effects. The bafiie 21' changes the direction of the flow of liquid to substantially horizontal, so that the liquid will impinge with considerable force against the baflie 20. As a result the liquid will be thrown partly upwardly, while the other part is broken up into individual streams and droplets by passing through the perforations 25 in baffle 20 (these perforations bearing the same reference numerals as similar perforations in vertical bafile plates 24) The up-rushing vapors thus encounter a spray of liquid rather than a water-fall, so that much better liquid-vapor contact is attained. If the amount of run-back exceeds the ability of the perforations in bafile 20 to take care of the liquid, some of it will overflow over the end of bailie 2B and then fall downwardly, but nevertheless there will still be the individual streams and droplets already mentioned.

If this baflle 20 were not provided, there would be a tendency to choke off the upward flow of vapors, thereby increasing the back-pressure of the apparatus. Of course, the downwardly extending bafile 2| serves to direct the flow of vapors so that they will more effectively exchange with the streams or walls of liquid in this region of what collectively is termed the lip l5 of the apparatus.

By also having the straight vertical baffles 24 similarly perforated, a similar effect is obtained at each of the succeeding lips I 5, l1 and I8.

While three separate cascading sections have been shown in each deck in the present exemplification of the present invention, it will be apparent that this is not to be construed as a limitation, as the drawings are purely illustrative and are not intended as working drawings or as limitations upon the present invention.

While the present invention has been described primarily in connection with a cascade-type of gas-liquid exchange apparatus, it will be evident that it is likewise useful in other types of such apparatus, for example in bubble towers, to insure a more even exchange between the vapors or gases and the liquid. Thus the downcomer provided with the upwardly curved or extending perforated bafile may serve to feed, the deck of a bubble tower, so that the vapors which have traversed the bubble-caps nearest the downcomer will be intercepted by a subdivided mass of liquid, as in the form of a spray of individual streams of liquid, such as will issue from the perforations in the upwardly curved and directed battle.

In a similar manner the invention is also useful with perforated plate towers that have individual decks, and, in general, with any kind of gas-liquid exchange apparatus in which liquid isfe'd from a higher to a lower deck. It is notdeemed necessary to illustrate each and every device in which the invention may be utilized, as, particularly, Fig. 5 serves excellently to illustrate the gist of the invention.

Accordingly applicants claim:

1. A gas-liquid contact tower comprising a housing a plurality of superimposed decks therein, each deck supporting a plurality of gas-liquid contact elements each of which elements comprises the combination of a series of liquid-flowproducing means arranged in staggered superim posed arrangement to eventuate a downwardly coursing flow of cascaded liquid, a series of troughs into which each of said cascades discharges, and means, including the lower sides of said troughs, for directing upwardly flowing gases into said cascading liquid; said troughs being provided with upwardly extending perforated plates; downcomers leading from an upper to a lower deck and supplied with liquid from the lowermost of said cascades and having narrowed lower outlets, liquid-receiving troughs below said outlets terminating in perforated upwardly curved impingement-plates, curved baffle plates at the bottom of said outlets so directed as forcibly to impel liquid discharged from said outlets in a substantially horizontal direction against said impingement plates, and through the perforations therein into the first of a next lower set of cascades, which next lower set is arranged at an angle relative to that of the one above it.

2. A gas-liquid contact tower comprising a housing; a plurality of superimposed decks therein, each deck supporting a plurality of gas-liquid contact elements each of which elements comprises the combination of a series of liquid-fi0w producing means arranged in staggered superimposed arrangement to eventuate a downwardly coursing flow of cascaded liquid, a series of troughs into which each of said cascades discharges, and means, including the lower sides of said troughs, for directing upwardly flowing gases into said cascading liquid; said troughs being provided with upwardly extending perforated plates; downcomers leading from an upper to a lower deck and supplied with liquid from the lowermost of said cascades and having narrowed lower outlets which are provided with curved baffle plates forcibly to direct discharged liquid in a substantially horizontal direction against a perforated plate prior to its discharge into the first of a next lower set of cascades.

3. A gas-liquid contact device for effecting more intimate contact between a gas and a liquid which comprises a housing; liquid-fiow-producing means therein for producing a plurality of sets of successive staggeredly positioned. downwardly flowing masses of liquid, each set being positioned below a previous such set; means, consisting of downcomers for conducting liquid from one set to the one below it, said downcomers being narrower at their lower outlet ends than at their inlet ends and provided with a deflecting baiile adjacent said outlet ends positioned to change the direction of liquid leaving the: downcomers into a generally horizontal direction, an upwardly curved perforated impingement plate being positioned at the beginning of the next lower of said sets against which liquid discharged from the downcomer may impinge and be given a generally upward direction as to such portions of the liquid which does not pass through the perforations, and means for passing a fluid up- 5; A gas-liquid contact tower wardly through said device countercurrent 'to' said downwardly flowing masses of liquid.

4. In a gas-liquid contact tower having a plurality of superimposed sets of cascade contact sections traversed by downwardly flowing liquid and in which liquid which has traversed one section is conducted through a downcomer to the next lower section, the improvement which comprises a curved deflecting baffle at the side of the outlet of said downcomer positioned so as forcibly to change the direction of how of the liquid from vertical to horizontal, and a therewith cooperating perforated impingement plate against which the liquid is hurled.

comprising a housing; liquid-flow prcducing means therein for producing a plurality of parallelly arranged sets of successively staggeredly positioned downwardly flowing masses of liquid, each of said sets being arranged at an 180 angle relative to the one above it; means for passing a gaseous fluid upwardly through said tower for exchange with liquid passing down through it; feeding means for supplying liquid to each of said sets, said feeding means comprising a downwardly directed chute having a broad inlet and a relatively narrow outlet, horizontal liquid-supporting means below said outlet and provided at one side with References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 489,147 Golding Jan. 3.; 1893 1,688,515 Baker et al Oct. 23, 1928. 1,770,221 Sweeny July 8,1930 1,836,505 Pritchard Dec. 15, 1931 2,007,759 Harmon July 9, 1935 2,051,545 Collins Aug. 18, 1936 2,071,526 Hochgesand Feb. 23, 1937 2,135,138 Kendall Nov. 1, 1938 2,289,889 Stick et al July 14, 1942 2,401,569 Koch June 4, 1946 2,457,667 Harmon Dec. 28, 1948 2,510,590

Kraft June 6, 1950

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