Патент USA US2405593код для вставки
Aug. 23, 1946'. ~ F. L. MELVILL _ 2,405,593 PACKING FOR VAPOR AND LIQUID CONTACTINGAPPARATQS Filed Feb; 4, 1944 o0wow. 23 23 23 22 #3 22 20 ' ATTORNEY Patented Aug. 13, 1946 ‘ ~ 2,405,593 UNITED STATES‘ PATENT OFFICE PACKING FOR VAPOR AND LIQUID CONTACTING APPARATUS ' Francis L. MeIvilI, New York, N. Y. Application: February 4, 1944, Serial No. 521,049 ‘Z Claims. 1, (01. 261—94') 2 This invention. relates to- packing for gas or or cries-crossed to form a. series oiintersections or points of. contact which are regularly and vapor and liquid contacting, apparatus. Although the invention has a wide range of utility, it- is particularly useful in connection with contact symmetrically‘ arranged in vertical staggered rows; and which de?ne.- liquid mixing and dis tributing zones. The streams of. liquid ?owing ing apparatus employed for the absorption, cooling, drying, cleansing or-h-umidifying of. gases, for the evaporation, cooling or heating of liq uids, or for reaction purposes. Such'apparatus may, for example, take the form of fractionating towers, scrubbers, cooling towers and the like. In such apparatus, a. packing is usually employed for e?ecting intimate contactv between the .de scending liquid and the ascending gas or vapor. As used herein and in the claims, the term “gas” includes vapor within its scope. The invention provides» a novel. packing for gas and liquid contacting apparatus which; avoids the presence of unequal. gas or liquid passages along. ‘the downwardly converging packing. eleé ments- respectively merge and intermix at the intersections of these elements, and. then subdi vide into corresponding streams as they ?ow , along the elements. diverging from saidiinter sections. The liquid. ?owing down a singleel'e ment of the. packing isregularly mixed. with liq. uid ?owing down an adjacent element. ofv the packing, and the resulting mixtureis thenre distributed among elements diverging from. ‘the mixing zone. each; of these. redistributed streams carrying substantially the same aliquot part of the liquid reaching. the mixing. zone.- from. above. and prevents channeling or segregation of the The nature of the invention. be. apparent ?owing gas in open spaces and of the liquid 20' ‘from the. following description when considered along surface areas, with the result that at in connection with the accompanying drawing any cross-section of the packing at right angles forming. a part thereof,.and inwhich: ' to the general direction of countercurrent ?ow Fig. 1- is a fragmentary axial vertical section, of the liquid. and gas, the. composition of. the somewhat diagrammatic, oi a‘ gas and liquid; con liquid. and gas .are- substantially uniform. 28 tacting' device containing a packing embodying The invention also provides a new and im the invention; ' ' proved packing of the general character de scribed; which feeds: andv spreads out the liquid Fig. 2 is a transverse section, somewhat dia grammatic, of. the contacting device, taken. on evenly in a thin ?lm- and in av regular predeter mined symmetrical manner as it descends. in a treating chamber, so that even. distribution of the liquid throughout the ?ow area of the cham her is aiiorded, which provides the- maximum of effective (i. e., wetted) surface area per unitv line 2-2 of. Fig. .1; 30 ' ‘ ,_ ' Fig. 3' is a view in elevation of one of. the pack ing elements: prior to assembly; ' Fig. 4. is: a view in elevation. showmg a pair of packing elements assembled to fijrman. inter secting liquid mixing and. distributing zone; ' of packing space, o?ers aminimumof: resistance - 1 Fig. .5; is a. view in. elevation of. a portion of to the passage of the ascending gas, andv a?ords the packing of Figs. .1‘. and 2. but. shown. on a. a maximum of intimacy of contact and interlarger scale; and action between liquid and gas, so that equilibrium Fig. 6 is a'horizontal section 'of- the packing. between the ?uid in either phase immediately taken on line. 6—6‘ oi Fig. 5. ' _ ' adjacent to the inter-face and the main bulk Referringtoz Figs. 1 and 2 of theadrawi'ng. the of the ?uid comprising the phase is rapidly gas. and liquid: contacting device is shown com. attained. prising a- vertical cylindrical. column or tower The invention further provides apackingoi the l0. containing the packing ll of the invention. general character described, which comprises a The. gas to be: contacted is delivered tothe lower series of simple, comparatively inexpensive. ele 45 portion‘. or the’ tower l0 below the packing U, ments requiring little or noshaping, and which and flows upwardly through’ the packing, while can be easily and expeditiously assembled. liquid. is; fed. to“ the uppenportio-n of the tower In carrying out. the features of the invention, above the packing, and ?ows downwardlythrough packing elements of small cross-section. and de the packing in thin. streamsandin intimatecon sirably in the form of rods, wires or tubes, are 59 tact with the ascending gas in. a manner'to- be arranged to form a network of. predetermined. described. The liquid is desirably delivered. to pattern, and to de?ne courses along which the liquid. is directed in. the form of thinv exposed the upper portion of the tower Ill and. over the streams encircling the elements. The packing. substantially evenly over the top of the packing ll, so that the liquid is. distributed substane elements arevdesirably straight and are. latticed packing H insuchscattered form asto be. spread 2,405,593 tially uniformly throughout the packing at its cal. The two layers 20 of elements 16 of each upper end. For that purpose, the liquid may be delivered over the packing H in spray form, or may be delivered by a liquid feed device simi lar to that shown and described in my copending packing sheet H are interconnected to form a sheet unit, as will be more fully set forth, and are latticed as described to de?ne a series of quadrilateral staggered meshes 22 large enough to prevent capillary ?lming of the down ?owing liquid across the meshes, but preferably as small as possible having regard for the liquid gas load. application Serial No. 536,306, ?led May 19, 1944, to feed the liquid in predetermined equally spaced tlunmstreams over the packing. \ The packih The adjoiningsections of-Zthe elements I16 form ‘51:5 shown occupying the‘centralj ‘ ' ing ‘the two upper; sides of each ineshi? are of portion of "the towerlil,"'while the‘ diametrically opposite side chordal sections 12 of the tower are m ,_ . equal length, and the adjoining sections of the elements forming the two lower sides of each left vacant or unpacked. A pair of partition ' .mesh are also of equal length, and are desirably plates 13 on the straight or chordalsides respec-_ tively of the packing I !, prevent ?ow-into or out. _' of the same length as the two upper element sections. The meshes 22 are advantageously in of the packing through the sides. The unpacked. the form of equilateral parallelograms, and are spaces l2 of the tower I!) may be sealed either at ‘ ‘speci?cally shown as square in shape. The the bottom or the top in any .‘manner wellriknown , in the art to prevent by-pass ?ow through these meshes 22_of each packing sheet I‘! are arranged spaces. The clearance between the arcuate pe~ in vertical rows with the vertices l8 of the meshes 20 of each row in vertical alignment, and the meshes of adjoining vertical rows medially staggered. ripheral portions of the packing H and the cor respondingjwall of the tower l0 may be sealed bya'ny suitable means,‘ asi'for example by means o’flaye'rs Hof glass wool. - ‘ ‘ -" ' . f'As a feature of the invention, the packing ll This construction lends symmetry to the arrange ment, and serves-to assure a more uniform mix ing and distribution of the liquid in its-downward cot prises alseries of ‘slender elements l6 which 25 ?ow through the packing l l The elements H5 in the two criss-crossed layers may be in'the form of wires,‘ tubes,‘ ?at strips or. 20 of each packing sheet ll desirably are inter the/like, and which are shown specifically, as solid cylindrical. rods. These'packing elements 16 are identical in transverse cross-sectional size and shape,‘ ,and their surfaces are of such material andj?ni‘shjasto be substantially-wetted by ithev liquid undernorinal'operating conditions. For connected at the intersections l8 ofv said ele ment preferably by welds 23. These welds 23 Y preferably are on the upper sides of the intersec tions l8 to prevent irregularities at the bottom of- each intersection l8 which would vbe undesir able, since they might cause the liquid to flow therefrom in the form of droplets or to be dis sirably of material having the necessary finish‘ t'oaff'ord the required wetting properties... These 35 tributed unequally. This would adversely affect the desired regularity in the distribution and flow packing’ elements - 1Bv are" of ‘sufficient diameter of the liquid as will be more apparent hereinafter. so‘ that they will have ‘substantial rigidity.‘ For that purpose, ‘the-packing elements 16 are de example, packing" elements one-tenth of an ‘inch inr'ydiameter will ‘be satisfactory, although'larger It will be understood that any number of these Welds 23 maybe-formed according to the overall size of the packing sheets I‘! or the size of the‘ or?tsmaller sizes may "be desirable depending upon packing elements.‘ For example, the welds 23 may the circumstances of'use ofthe packing. . be formed at each intersection 18, or at spaced Although the packing elements l6 are shown in cylindrical'form, as far ascertain aspects of the The lengths of the packing elements l6 vary invention a'reiconcerne'd, they may be of any suit ablelzsymmetrical cross-sectional shape. .For ex-. 45 according to the overall size of the packing sheets I1, or the cross-sectional size‘ of the elements. ample, the surface of‘ the elements'?i may be For example, in the smaller packing sheets, the nod-Yea; ?uted or l'otherwisetreat‘ed to form a intervals.‘ regular pattern ‘thereon: ‘The grooves may ex tend parallel to the longitudinaliaxis of the ele ments l6,’ or may extend helically‘or in theform of a thread. Such'surfac'e grooving of the ele-: ments" it maybe provided to increase the liquid carryingca'pacity of; the rods. Also, instead, of using single ‘rods-Wires or‘the like, as far as cer ' Y ' ' elements 16 may be made to extend integrally from edge to’ edge of the sheet, while in the larger packing ‘sheets, theelements, and especially the longer ones, may consist of di?erent sections po sitioned in axial abutting alignment. These axi ally _aligned elements 16 may be'butt-welded to‘ gethenif desired.‘- ' ' tain aspectsof the ‘invention are concerned each 55 rl‘he packing sheets I‘! as described are sub stantially identical as far as the size'and shape of the packing elements It may consist of mul tiple wires braided or helically twisted together, or laid side by side; V Y’ ‘ i , ~ of their meshes 22 and the diameter of their ele ments 16 are concerned, and are arranged verti— cally in lateral face to face contact with the ‘ele The packing elements‘ iii are arranged to form aplurality of-vertical units‘ or sheets IT in face 60 ments of alternate layers 20 running in the same‘ oblique direction, to form the composite packing to‘falce contact, each comprising a series of ele H. Thesepacking sheets I‘! desirably are so ar inents criss-crossed-‘to'de?ne a plurality of liquid ranged that the meshes 22 of one sheet are in mixing and distri uting junction zones 18; In horizontal registry with the meshes of the other the speci?c‘ form'of the‘irivention shown, each vertical packing sheet 11 comprises two inter» 65 sheets, ‘as shown in Figs.- 5 and'6. ', However, as far as certain aspects ‘of, the invention‘ are con‘~ facing layers 2B of packing elements arranged in cerned, the packing sheets H may be relatively 'c'rissicross fashion. ; The elements it‘ of one layer 2B-in'a5p'acking sheet I‘! are equally spaced and displaced vertically, so that the meshes 22 of one packing sheetv I‘! ‘are out of phase with the'meshes arranged‘obliquely'in parallel-in one‘ vertical plane, and the elements of‘ the other layer of the 70 of adjoining sheets. :For example, the meshes 22 of‘ alternate packing sheets rll' may be in hori-' "sense sheetare spaced the same distance ‘apart zontal registry, while‘the meshes of intervening and ‘are similarly arranged obliquely’ in parallel packing sheets maybe ‘in horizontal‘ registry but displaced with'respect tofth‘e' ‘meshes ‘of tionsireverseyto those ‘of the elements of, the ?rst 76 medially the other sheets.‘ TInrthis‘latt‘er' arrangement‘, the laye‘rs'but atthesame’inclination with the verti iii-a vertic'aliplaneebiitj extend in oblique direc 5 vertices of the. meshes 22 of one packing sheet I‘! would be disposed centrally with respect to the. meshesof adjoining sheets. ' The packing sheets l1 may be interconnected together, or may be relatively displaceable verti cally. This latter arrangement may be preferred, where for example, it is desirable to vibrate some or the: sheets I]: edgewise with. respect to others to promote turbulence‘ in the ?uid. ?ow or to pre» vent-clogging of‘ the packing. Inthe use of‘. the packing H, the liquid with. which it is. desired to contact the ascending gases is delivered to the top section of the packing as described, and is: divided into; a number of pre 6 at any point in any plane at right- angles to the general directi'onof ?ow. Maximum intimacy of‘ contact and maximum interaction.between-‘liquid andgas is obtained, and; equilibrium is rapidly es tablished between the material in either vapor or liquid phase immediately adjacent to'theilnter face: and the main bulk of the: material compris ing‘the phase. - ' ' Orr any cross-section of the packing H at right 10 angles to the, general direction of ?ow-oi the liq-r uid and gasv the composition of‘ the gas; is sub stantially the samev and the composition of the liquid in its constituent streams- is substantially thesame. The pressure drop of‘ the liquid pass determined exposed. streams which flow obliquely 15 ing- through the packing Ill and the amount of downwardly along the elements It in regular zig-r liquid retained by the packing under normal op zagcourses. The liquid ?owssubstantially evenly erating conditions is comparatively low. A com in: av series. of thin films over the. surfaces of the paratively long path of travel of the liquid pass packing elements: in a direction generally counter ing through the packing H is provided so that to the direction of flow of the gas. The maxi 20 retention of the liquid for a- period long enough mum-of liquid? surface thereby is exposed to. the to assure the necessary saturation or interaction action of‘ the ascending gas. The liquid stream with the gas is assured. flowing down along a single element i=6 of the Inasmuch as each of the elements extends in packing ll merges‘ at a juncture l8. with the liq a downwardly inclined: direction from the inner uid stream ?owing down ‘an adjoining element. , wall. of the tower l0, liquid which reaches the wall At this. juncture t8’, the two streams are thor by way of some of the elements will ?ow away oughly intermixed, and the resulting mixture is from the wall by way of other elements andIIthu-s then subdivided and redistributed equally between will. tend to retain the liquid. in the packing and the elements diverging downwardly from the prevent short circuiting. ?ow down the wall of juncture. Each of these diverging elements con thetower. stitutes part of another pair of elements con The velocity of the vapor v?owing upwardly verging towards a juncture it, so that. the two. through the packing: will‘ cause or tend tov cause diverging distributed streams merge and inter the liquid on the elements to assume a stream mix with other adjoining streams, and then again lined or tear drop. shape suchas would present become subdivided. This process is repeated; so 35 the minimum resistance; to the ?ow of' vapors that uniform mixing and distribution of the liq and this, together with the surface effects which uid in thin ?lms throughout the width oi'each become pronouncedv with‘ thin films of liquid, will packing sheet IT is assured. Also, since the pack have the e?ect of distributing: the liquid over the ing sheets I‘! are in lateral face to face contact, surfaces. of the elements with a tendency for a the liquid in one sheet is not only distributed and major part ofthe liquid to flow down» the upper . mixed substantially uniformly throughout the paits of the-elements, the amount of‘ liquid so width of‘ the sheet, but is also distributed and ?owing. increasing with. increased vapor ‘velocity. intermixed with the liquid_ of adjoining packing The effect of this is to insure the maximum ex sheets. in this manner, substantially uniform posure of the liquid to the' vapor and to facili mixing and. distribution of the; liquid throughout tate the mixing of the streams of liquid ‘at the the entire horizontal. section of the packing “ is juncture points 18:. assured. ' Since many- changes can be made in the apé If the flow along the various elements It is paratus disclosed, and many apparently widely not. equal, the degree of inequality will tend to different embodiments: of the invention can be become‘prog-ressively reduced due to the fact that ,, made without departing from the‘ scope of the each element will divide, or will tend to divide, claims, it is intended that all matter contained the whole of the liquid reaching a given mixing in the above description or shown in’ the accom zone [8 equally with‘ its element partner in that panying drawing shall be interpreted as illus zone. This is. particularly important in the up trative-and notin a limiting sense. per section of the packing I I, where the liquid What is claimed is: feed may not be deposited uniformly over the top 11. In gas and liquid contacting apparatus com of the packing. By the equalizing process de prising a column with a liquid inlet and a gas scribed, the distribution of the liquid under these outlet in the upper part thereof and a gas inlet conditions will become uniform in the upper sec and liquid outlet in the lower part thereof, said tion of the packing H. Uniform distribution of column being adapted for countercurrent ?ow, a the liquid when once attained near the top of the packing for the column comprising a plurality packing I I will persist to-thebottom thereof. The of vertically extending sheets disposed in the path gas ?ows generally upwardly and tortuously of flow of said‘ gas through the column, each sheet through the meshes 22‘ countercurrent to the liq comprising straight slender elements which are uid and contacts the exposed thin liquid ?lms vertically inclined and in contact, the elements on the packing elements IS. The disposition of being arranged to form a plurality of mixing zones the meshes 2-2‘ insures the necessary turbulence ' comprising a series of intersections in spaced to secure thorough mixing, thus avoiding the loss horizontal and spaced vertical rows, said rows of efhciency which results when gas at the liquid and‘ said intersections being closely spaced; the gas interface is not mixed as rapidly as possible ' distance therebetween being sui?cient' to form with the main bulk of the gas, and when other spaces between the intersections large enough to purely local conditions within the packing ll prevent capillary ?lming of the liquid there tend to vary the composition of the gas across across. any section of the tower Ill. The velocity of 2. In gas and liquid contacting apparatus com the gas upwardly will be substantially the same 75 prising a column with a liquid inlet and a gas 2,405,593. outlet‘ in the upper part thereof and a gas inlet and‘ liquid outlet in the lower part thereof, said column being adapted for countercurrent ?ow, a packing for the column comprising a plurality of vertically extending sheets disposed in face to face contact and in the path of flow of said ‘gas through the column, each sheet comprising straight slender elements which are vertically’ inclined and in contact, the elements being ar ranged to form a plurality of mixing zones com prising a series of intersections in spaced hori zontal and spaced vertical rows, said rows and said intersections being closely spaced, the dis tance therebetween being su?icient to form spaces between the intersections large enough to prevent capillary ?lming of the liquid thereacross. V 3. In gas and liquid contacting apparatus com prising a column with a liquid inlet and a gas out let-in the upper part thereof and a gas inlet and liquid outlet in the lower partthereof, said col umn being adapted for countercurrent ?ow, a packing for the column comprising a plurality of ‘ 5. In gas and liquid contacting apparatus com~~ prising a column with a liquid inlet and ages outlet in the upper part thereof and ages inlet and liquid outlet in the lower part thereof, said column being adapted for countercurrent ?ow, a packing for the column comprising a plurality of . vertically extending sheets disposed in face to" face contact and in the path of ?ow of said gas through the column, each sheet comprising a fabric of straight slender packing elements which are vertically inclined and are regularly arranged in accordance with a predetermined pattern to form a network provided with a plurality of ver-i tically extending zig-zag sections having uniform alternate turns, and de?ning regular predeter mined flow paths along which the liquid is adapt ed to ?ow in de?nite streams respectively, these‘ sections being joined at staggered intervals to‘. de?ne mixing zones where the streams merge and; then subdivide as they descend, said elements be ing so arranged that the mixing zones are closely: spaced, the vdistance therebetween being suf?-. cient to form meshes of a size to-prevent capil vertically extending sheets disposed in face to lary ?lming of the liquid thereacross. face contact and in the path of flow of saidgas through the column, each sheet comprising a net 25 6. In gas and liquid contacting apparatus com-. work of straight slender elements which are ver prising a column with a liquid inlet and a gas. outlet in the upper part thereof and a gas inlet and liquid outlet in the lower part thereof, said column being adapted for countercurrent flow, a meshes, each having diagonally opposed junction corners substantially vertically aligned and de 30 packing for the column comprising a plurality of vertically extending sheets disposed in face to ?ning liquid mixing and distributing zones re face contact and in the. path of ?ow of said gas spectively, the elements bounding each of said through the column, each sheet comprising two meshes diverging obliquely downwardly in pairs or more criss-cross layers of slender packing ele-_ from the upper junction corner of said latter mesh at substantially equal angles with the ver 85 ments of predetermined shape which are vertical-r 1y inclined, the elements of each layer extend tical, and converging towards the lower junction ing obliquely in the same general direction, and corner of said last-mentioned‘ mesh at substan . the elements of adjoininglayers extending ob tially the-same angle with respect to the verti liquely in transverse directions to form a series cal, said elements being so arranged that the mix ing and distributing zones are closely spaced, the 40 of liquid mixing and distributing intersection zones, at least some of said elements being in distance therebetween being su?icient to form contact at said zones, said elements beingso ar meshes of a size to prevent capillary ?lming of ranged that the liquid mixing and distributing the liquid thereacross. V intersection zones are closely spaced, the distance 4. In gas and liquid contacting apparatus com prising a column with a liquid inlet and a gas 45 therebetween being sufficient to form meshes of a size to prevent capillary ?lming of the liquid outlet in the upper part thereof and a gas in-v let and liquid outlet in the lower part thereof, 7. In gas and liquid contacting apparatus com said column being adapted for countercurrent prising a column with a liquid inlet‘ and a gas flow, a packing for the column comprising a plu outlet in the upper part thereof and a gas inlet rality of vertically extending sheets disposed in and liquid outlet in the lower part thereof, said face vvto face contact and in the path of flow of column being adapted for countercurrent ?ow, said gas through the colunm, each sheet com— a packing for the column comprising a plurality, prising a network of obliquely extending slender of vertically extending sheets disposed in face elements which are vertically. inclined and are to face contact and in the path of flow of said regularly shaped and regularly criss-crossed to gas through the column, each sheet comprising a form de?nite vertical rows of equilateral quad plurality of straight elements which are verti rilateral, meshes of substantially the same size cally inclined and are regularly arranged to form and ‘shape, having diagonally opposite vertices a series of intersections de?ning liquid mixing in substantially vertical alignment, the meshes ‘ and distributing zones, at least some of the inter-_ of one vertical row being staggered with re secting elements being interconnected by welds spect to the meshes of the adjoining vertical formed on the upper portions of the intersec-~ row, and arranged in lattice relationship there tions, while the lower, portionsof the intersections‘ with to de?ne a series of junction zones towards are‘ free of welds, said elements being so arranged which the elements converge in pairs obliquely downwardly and from which the elements diverge ,- that the intersections are closely spaced, the dis tance therebetween being su?icient to form in pairs obliquely downwardly, at least some of tically inclined and are regularly arranged and in contact to form de?nite rows of quadrilateral thereacross. . _ ' meshes of a size to prevent?capillary ?lming of said elements being in contact at the junction the liquid thereacross. zones, said elements being so arranged that the junction zones are closely spaced, the distance FRANCIS L. MsLvnL. therebetween being sufficient to form meshes of a 70 size to prevent capillary ?lming of the liquid thereacross.