US2051545A

US2051545A - Contact apparatus

Info

Publication number: US2051545A
Application number: US666144A
Authority: US
Inventors: Raymond R Collins
Original assignee: Lummus Co
Current assignee: CB&I Technology Inc
Priority date: 1933-04-14
Filing date: 1933-04-14
Publication date: 1936-08-18
Anticipated expiration: 1953-08-18

Description

Aug` 18, 1936- R. R. coLLlNs 2,051,545

CONTACT APPARATUS Aug. 18, 1936. R. R. coLLlNs CONTACT APPARATUS Filed April 14, 1933 3 Sheets-Sheet 2 .i E n n-:1 r-1 Aug. 18,1936. R. R. COLLINS CONTACT APPARATUS Filed April 14, 1933 3 ShetS-'Sheet 3 poor distribution ofthe Patented A ug. 18, 1936 UNITED 's'rATEsPA'rENT OFFICE 21,051,545 -CONTACT APPARATUS Raymann a. comm, Forest mus, N. Y..

to The Lummus Company,

assigner New York, N. Y., a

corporation of Delaware l Application April 14, 1933, Serial No. 666,144

The present invention relates 11 Claims.

to contact apparatus and .more particularlyto apparatus for promotingliquid-to-liquid contact, as in liquld extraction process, or liquid-to-gas contact, as

in scrubbing and .rectifying processes.

In the usual forms of liquid extraction apparatus, the degree of extraction is limited by the eiliciency of contact which is frequently low because of the formation of channels and the Even with the usual liquid across the column. expedients for promoting contact, such as Raschig rings, channeling is not completely prevented and uncontacted streams may form throughout the length of the tower.

The object of the present invention is to provide an apparatus particularly extraction processes and useful in liquid also suitable for gas-toliquid contact, in which eiective distribution of the fluids across the column is maintained, and in which undesirablel channeling is practically avoided. To this end,

the present invention comprises the apparatus hereinafter' described and particularly defined in the claims.

In the accompanying diagrammatic sectional drawings, Fig. 1 is a elevation of the preferred form of the invention; Fig. 2 is a section on line 2-2 of Fig. 1; 3-3 of Fig.

view of a number of units; Fig.

of a portion of one of the units;

Fig. 3 is a section on line l; Fig. 4 is an enlarged sectional 5 is a side view Fig. 6 is a vertical sectional view of a modied unit; Fig. 7 is a perspective view of still another modified form of the invention;

Fig. 8 is perspective view of a modification embodying a unitary arrangement; and Fig. 9 is a View,

one of the units of Fig. 8.

The invention is herein scribed as embodied in a partly in section, of

illustrated and deliquid extraction apparatus particularly constructed for a solvent method of separating naphthenic and paraftlnic oil components from a lubricating stock.

some forms of the extraction process, the lubricating stock is passed in countercurrent to a single solvent which vhas selective dissolving powers for either the naphthenic or the parafflnic oil groups, while another process contemplates passing inv countercurrent two solvents which have selective dissolving actions on the two oil groups, the oil feed being then introduced into a mediate point of the countercurrent path. The apparatus shown in Fig. 1 is particularly constructed for the practice of the extraction operation of the second type involving the use of two solvents.

The apparatus comprises a c olumn 8 having II) would be omitted, the `oil feed Y duced through one of the -zles.

at a mediate point a feed inlet I0 for introduction of the oil to be subjected to the extraction process. Near the bottom of the column is an I4 for introducing a heavier solvent having selective dissolving power for the naphthenic components. At the bottom is a draw-off I6 from which is withdrawn the extracted naphthenic components in mixture with some of both solvents and at the top is a withdrawal pipe IB for removal of the extracted parafllnic components which are also associated with some of both solvents. A vent pipe 20 is provided at the top. In operation of the process, the heavy solvent introduced at Il descends, and the lighter solvent, introduced at I2, ascends through the column.` In a single solvent process, the pipe would be intropipes I2 or I4, and the solvent wouldl be introduced through the other pipe.

Between the inlets III and I2 there are arranged a plurality of contact units, indicated generally at 22. of liquid collecting troughs 24 arranged in rows across the column, the rows being staggered or offset, as shown in Fig. 1. Connected to the bottom of eachtrough are two inclined perforated plates 26, the ends of which are immersed in troughs of the row next below, the construction forming a diamond-shaped arrangement of the plates. The plates are perforated, as shown in Fig. 4. The material of the perforations may be struck out to form louvers V28. Each trough is provided with a serrated overow edge shown in Fig. 5, to permit substantially uniform overflow of liquid, regardless of any slight failure to level the column exactly. The plates 3| of the bottom row are imperforate, and adjacent plates converge to form narrow transverse openings 32 in each of which is disposed a plurality of nozzles 34. Above each nozzle is a deflector 36 for dispersing liquid flowing through the noz- The nozzles are all connected together by pipes 38 which are connected tothe inlet pipe I2. At the top of the column, the pipe Il connects with a series of pipes 40 which distribute the heavy solvent into the troughs 2-l` of the uppermost row'. The feed pipe I0 is similarly connected with nozzles 42 disposed internally of the units at a mediate section of the column.

' In operation, the light and heavy solvents are continuously introduced by the pipes I2 and Il The units comprise a plurality and the feed oil is introduced by the pipe I8. The entire column is filled with liquid. 'Ihe heavy solvent flowing into the uppermost troughs 24 overflows and runs down the inclined plates I6. At the same time, lighter liquid passing upwardly through the column goes through the perforations of the plates and contacts intimately with the descending heavy solvent. In this operation, the heavy solvent is denuded of its paraillnic constituents and is enriched by naphthenic constituents extracted from the ascending stream. The heavy liquid finds its way to the troughs of the row next below, from which it overflows into the succeeding rows of troughs. The action o f contact at the surfaces of the plates is enhanced by the fact that the ascending lighter solvent carries some particles ofthe heavier material upwardly into the diamond-shaped areas, after which these heavier particles separate from the descending stream and descend directly into the troughs. A fairly turbulent condition arises by which complete and effective contact between allparticles of the several liquids is assured. It will be observed that since the liquid collecting in the troughs is always heavier than that rising through the diamond-shaped areas, there is no opportunity for ,the lighter liquid to pass into troughs but, on the contrary, it is obliged to ascend and pass through the perforations, thereby promoting the turbulent contact of the liquids. lIn the lowermost row, the descending liquid is caused to converge toward the nozzles 34, thereby promoting a nal intimate contact which assures substantially complete removal of the remnant of paramnic constituents. 'Ihe bottom of the column is provided with an enlarged settling chamber 44 in which opportunity is afforded for segregation of the material into layers, the lower layer being withdrawn at I8. Similarly, the upper section of the'column is provided with an enlarged separating chamber 46 to permit segregation of the extracted parafnic oils from any heavier components which may tend to rise toward the top of the column.

It will be observed that neither vthe descending nor the ascending liquid is permitted to pass in any well-defined inactive channels through the column. 'I'he descending liquid divides at each trough into two streams and accordingly, there is a definite transverse motion of the liquid across the column. Similarly, the ascending liquid is divided into two streams within each diamond-shaped area. Thorough distribution throughout the Lcross-section of the column Vis thereby assured. The distribution and 'contact are attained, however, while keeping a definite classification of the streams at any level. Descending heavy liquid .passes from trough to trough over the upper surfaces of the plates without being -permitted to pass through the perforations, while the ascending lighter liquid moves upwardly through the plates without mixing with .the collected `liquids in the troughs. Accordingly, `:the proper differences in density are maintained to assure progressive countercurrent action whereby the descending heavy solvent picks `up increasing quantities of naphthenic components. and the ascending lighter solvent picks Aup increasing quantities of parafflnic components.

A modified and somewhat simpler form of the invention is shown in Fig. 6. Each plate 58 is formed at its upper end with a vertically extending portion 52 and an inturned portion 54.

The portions 52 of adjacent plates are riveted or welded together and a triangular-shaped trough is thereby formed. The plate 58, as shown in Fig. 6, is perforated according to any desired pattern. Louvers, similar to those indicated at 28 in Fig. 4 may be used, and these contribute to completeness of contact by promoting turbulence in the cascading stream of heavy solvent. However, plain perforated plates are entirely satisfactory since the ascending liquid is forced to contact intimately with the descending stream.

Ineither form of the invention, the column is highly eil'icient since the only portion of the cross-section not available for contact is that taken up by the troughs themselves, which are of comparatively small area. The area available for contact may be as high as of the total cross-section of thecolumn, as compared with about 65% for Raschig ring columns oreother towers of the filled type.

In the construction shown in Fig. 7, the inclined plates are arranged in the form of conical surfaces co-operatingV with collecting decksv which take the place of the .troughs of the modication irst described. As shown in the drawings, a plurality of decks 18 are arranged at successive levels within the shell, each deck being provided with regularly spaced openings within which cylindrical overilow lsleeves 12 are welded. The upper edge of each sleeve may be serrated. Co-operating with each sleeve 12 is a coneshaped contact device 14 provided with perforations for promoting contact between the countercurrent fluid. At the bottom, each cone is provided with a ring 18 surrounding the overilow sleeve and suitably attached thereto by bolts or other securing means 18. At the top,

.each cone has av small collecting pan 88 sur-l rounded by an' upstanding serrated overow sleeve or Weir 82. A second cone 84 has a ringshaped bottom portion 86 fitting within the sleeve 82, and an upper ring section 88 secured to the cylindrical overnow sleeve 12 oi' the deck next above. The apparatus operates in exactly the same fashion as that shown in Fig. 4, the decks 18 and the collecting pans 88 serving the same function 'as the troughs 24. The conical contact devices serve the same purpose as the inclined plates. It will be observed that the liquid collecting on each deck 18 is caused to distribute and divide so that all opportunity for channeling is prevented. 'I'he lighter liquid rising from below passes internally of the lower cone 14 ot each unit and out through the perforations, and thence inwardly through the perforations of vthe upper cone 84, this process being repeated from deck to deck. The introduction of liquids is accomplished in the same manner as inthe arrangement previously described.

A .simple unitary arrangement is shown in Figs. 8 and 9. The entire column is made up of a plurality kof individual units, all of thev type shown in Fig. 9. Each unit comprises two opposed perforated cones 88 and 82, the lower cone 88 having at the top a collecting pan surrounded by a sleevev 84, as in the arrangement shown in Fig. 8. The two cones are held together by a series of braces 86, each welded to the upper cone and the sleeve 84. Except for the braces 86, the cones are identical with those shown in Fig. 7.

The bottom ring 88 of the lower cone is immersed in an overflow section which comprises an overflow sleeve |88 preferably having an up- 'per serrated edge and a.

surrounding hexagonal sleeve |02, the hexagonal sleeve being connected with the clindrical sleeve by a horizontal tray portion |04. The bottom ring of the cone is secured to and spaced from the sleeve, as indicated at |06. The units are nested together, as indicated in Fig. 7, the hexagonal sleeves joining together to form in effect a continuous deck. The uppermost units are supported by the units below. It is unnecessary to attach the hexagonal sleeve portions of adjacent units together, since the column is almost completelyiilled by the joining hexagonal surfaces. It will be observed that the side portions of the hexagonal sleeve |02 are appreciably higher than the overflow edges of'the cylindrical sleeves |00, in or der to prevent overflow through the joints. between adjacent units. For this reason, little distribution of descending liquid takes place, each column of individual units acting more or less independently of the others, but adequate contact and classification are nevertheless obtained, and Ythe construction has the advantages of simplicity and economy of manufacture.

'Although the invention has been described above as embodied in an apparatus for practicing a liquid extraction process, it is equally suitable for liquid-to-gas or liquid-to-vapor contact,

`as in scrubbing, washing or rectifying systems.

For example, the column, insubstantialy' identical form to that shown in Fig. l, may be used for steam disti1lation. The oil to be distilled is first heated and then charged into. the column through the feed pipe I0, steam is introduced by the pipe l2, and reflux vliquid is introduced at I4. Vapors and residual product are withdrawn from the column at i8 and I6, respectively. The vapors ascending the column paas through the plates and contact with descending liquid which passes from trough to trough over the upper surfaces of. the plates. This type of column is especially suitable for vacuum distillation, since excellent contact may be promoted without introducing excessive back pressure.

Having thus describedthe invention, what is claimed is:

1. Contact apparatus comprising a column, a plurality of staggered rows of troughs, and a plurality of rows ofinclined perforated plates, each attached at its upper end to a trough and immersed at its lower end in a trough of the row next belowcertain of said troughs receiving the lower ends of a plurality of said plates and having a plurality of `downwardly extending diverging plates attached thereto.

2. Contact apparatus comprising a column, a plurality of staggered rows of troughs, and a plurality of inclined perforated plates, each attached at its upper end to a trough and immersed at its lower end in a trough of the row next below, each plate having fins extending outwardly from the plate.

3. Liquid extraction apparatus comprising a column, a plurality of staggered rows of troughs, a pluralityof inclined perforated plates, each attached at its upper end to a trough and immersed at its lower end in a trough of the row next below, a bottom row of unperforated plates, adjacent plates converging to a narrow opening. means for introducing a liquid into the openings,

and means for introducing a liquid into the uppermost troughs.

4. Liquid extraction apparatus comprising a permost troughs, and means column, a plurality of staggered rows of troughs, a plurality of inclined perforated plates, each attached at its upper end to a trough and immersed at its lower end in a trough of the row next below, a bottom row of unperforated plates, adjacent plates converging to a narrow opening, means for introducing a liquid into the openings, and means for introducing a liquid into the upfor introducing a third liquid into a mediate point of the column.

5. Contact apparatus comprising a column, a plurality of inclined perforated plates in the column, means for passing a liquid downwardly over the upper surfaces of the plates, and means for passing a lighter fluid upwardly through the prforations in the plates, the plates being provided with louvers over which the descending liquid cascades.

6. Contact apparatus comprising a column, a

. plurality of contact units in the column, each including an integral plate having an inclined perforated portion and an upper portion oppositely inclined, two of such units being attached together, whereby said upper portions form a trough. 'l

7. Contact apparatus comprising a column having a plurality of decks, overflow sleeves in each deck, an lupper perforated conical contact member depending from each overflow sleeve, a lower conical contact member surrounding a sleeve of the deck below, and having a collecting pan at the top, and an overflow weir at the edge of the collecting pan.

8. Contact apparatus comprising a column, a plurality of contact units, each consisting of an overflow sleeve and a surrounding polygonal sleeve, a horizontal tray between the sleeves, a

perforated cone upstanding from the overflow 9. Contact apparatus comprising a column, a plurality of contact units, each consisting lof an v overflow sleeve and a surrounding polygonal sleeve, a horizontal tray between the sleeves, said units being arranged at different levels in the column, and inclined perforated plates to direct the flow of liquid from one overflow sleeve to the tray next below.

l0. Contact apparatus comprising a column, a plurality of upwardly facing liquid collectors ar.- ranged at each of a number of different levels in the column, perforated contact members connected at their upper ends to said collectors and having inclined surfaces extending downwardly toward the collectors at the level next below, said surfaces converging toward said last-named collectors, means for passing a fluid downwardly over the surfaces and through the collectors successively, and means for passing a fluid of less density upwardly through the perforations.

11. Contact apparatus comprising a column, a plurality of upwardly facing liquid collectors at a number of different levels in the column, perfo- C while passing a fluid ...o