CA1264285A - Mass-transfer apparatus - Google Patents
Mass-transfer apparatusInfo
- Publication number
- CA1264285A CA1264285A CA000509638A CA509638A CA1264285A CA 1264285 A CA1264285 A CA 1264285A CA 000509638 A CA000509638 A CA 000509638A CA 509638 A CA509638 A CA 509638A CA 1264285 A CA1264285 A CA 1264285A
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- Canada
- Prior art keywords
- froth
- retainer
- mass
- tray
- bars
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
ABSTRACT
A mass-transfer apparatus in the case whereof there are contained at least one horizontal perforated tray and a froth retainer fitted directly to the tray. The froth re-tainer consists of upright bars arranged to form a grid the cells whereof communicate with one another. The lower por-tions of the bars of the froth retainer which are contiguous with the tray are solid and the upper portions of the bars have perforations communicating where through are the cells of the grid.
A mass-transfer apparatus in the case whereof there are contained at least one horizontal perforated tray and a froth retainer fitted directly to the tray. The froth re-tainer consists of upright bars arranged to form a grid the cells whereof communicate with one another. The lower por-tions of the bars of the froth retainer which are contiguous with the tray are solid and the upper portions of the bars have perforations communicating where through are the cells of the grid.
Description
1~4~85 ~.~SS-TRANSFER APPARATUS
The invention relate~ to chemical and petroleum en-gineering and has specific reference to mas~-tran~fer appa-ratu~.
The invention can be of utility in Yarious installa-tions for heat and mas~ tran~fer ~etween a liquid ~nd a ga9 which find applicatio~ in the chemicalj gas, petroleum ri-fining, metallurgical and ~ood indu~trie~ as well as in oth-er field~. rrhe apparatu~ di~clo~ed can cope with the proces~-e~ o~ absorption, fractination, desorption and ~as scrubb-ing.
The invention holds out ~pecial promise as an item of the equipment of gas-procesaing plant~ and separate in~talla-tions u~ed in the oil and gas industry for treating natural ga~ aLd condensate preparatory to conveying over long dis-tance B -Cryogenic ~ir-separation plant~ is a prO~peCtiVe field of application of the invention.
A sharp increase in the capacity and ef~ectivenes~ of mass-tran~er columns i~ a problem nowaday~. The point i8 that the bubble trays of the traditional de~ign u~ed in these columns do not permit the flow rate of gas or vapour through the net cross-~ectional area of a column to be in-creased oYer a given minimum, which i8 1.2-1.5 mJs for an air-water system under the atmospheric conditions. The prob-lem i~ coped with by increasing the diameter of ma~s-trans-fer apparatus which can be a~ large as 3 to 12 m in high--capacity in~tallations.
Thi~ approach iB, however, unacceptable for drilling ships and offshore rigs where ~pace is at premium.
Xnown in the art i~ a ma~-tran~fer apparatus for ga~-to-liquid contact in the ca3e whereof there are contained one perforated tray, or several ~uch tray~, Qnd a sprayer (cf. Pozin ~.E. "Pennye ~azoochi~titeli, teploobmenniki 1 absorbery", Ieningrad, 1959, p. 51).
A liquid fed from the ~prayer forms a layer of mobile froth on the tray to ab~orb certain gases or dust from the bulk gas flow.
The capacity of the known apparatu~ is low, for the flow rate of the gas through the net cross-aectional area theIe-of is slow, commonly not over 2 or 2.3 m/8, and the layer of froth on the tray i8 thin (around 100 mm).
Any attempt to boost the capacity gives ri~e to tur-bulence which leaves some portions of the tray uncovered with the froth, permittin~ some of the gas to pass through the tray unprocessed. This reduce~ the effectivene~a of the apparQtus.
Also known is a mass-tran~fer apparatue which, in addi-tion to heat and mass tran~fer, can cope also with the wet 8crubbing of gase~ (cf. USSR Inventor'~ Certi~icate No. 434,969, Int. Cl. B01 d 47/04). The ca~e of the known apparatus contains perfor~ted tray~ each whereo~ is ~itted with a contiguous froth retainer in the form of a grid made up of upright barA. The height of ever~ bar i8 0.2 to 0.6 time the thickne~ of the froth layer, and the net cross-~X64;~85 -eectional area of a grid is at lea~t 0.8 time the net eros3-_eectional area of the apparatus. 2erforation~ are provided in some of the bsrs of the froth retainer, next to the sur-face of the tray.
The main purpose the froth retainer is to set up on the tray a thick and ho~ogenous layer of froth vJith fine cellular ~tructure and to pro~ide for a continuous flow of the phases at their interface without spparent fluctuation~.
In other ~Jord~, the ~roth retainer eliminate turbulence and, con~equently, increase the capacity of the apparatus.
Ho~ever, the effectiveness of the process of heat and mas~ transfer taking place in the known apparatus at the gas flow rates over 2.6 to 3.0 m/~ iB low (for the air-water syRtem under the atmo~pheric conditions). Intermittent eddi-e~ brou~ht about at the top of the froth layer expel eome of the liquid from grid cells along the axes thereof, render-ing this portion ineffective as a medium for an active mass transfer or dust recovery. An accompanying splashing im-pair~ the capacity of the apparatu~ and the effectivenes~ of ma~ transfer proce~ses.
The perforations in the lower portion~ of some bars of the froth retainer cannot provide for a u~iform di~tri-bution of the liquid flow over the entire surface of the trsy.
The main object of the inYention i~ to provide a ma~e-transfer apparatu~ a froth retainer whereof i8 deBigned ao as to increase both the capacity and the ef~ecti~eneee of the apparatus, uniformly distribute the liquid in the form of a froth with fine cellular structure over the en-64~ 85 tire surface of ~ tray and prevent splQ3hing of the liquidalong the a~es of grid cells should the g~ flow rate be speeded up.
~he essence of the invention consists in that in a mas~--transfer spparatu~ in the ca~e whereof there are contained at least one horizontal perforated tray and a froth retain-er in the forn of a grid made up of upright bars which are fitted directly to the tray and form intercom~ected cells, according to the invention the lower portions of the bar~
of the froth retainer are made solid and the cell~ of the grid communicate with one another by way of perforations in the upper portions of the bars of the froth retainer.
The perforations flowing wherethrough from one cell to another i~ the froth exercise a self-instituted flow control owing whereto the liquid ie uniformly distributed over the relatively great area of the tray. The ~olid por-tions of the foam retainer bar~ ~erve the same purpo~e as well, preventing undesired accumulations of the liquid in depre~sions or at obliquities of the tray.
It is expedient that the solid portions of the bar~
of the froth retainer are of a height which is 0.1 to 0.5 time the overall height of these bars.
~ his plan is conducive to a u~iform distribution of the froth layer over the entire surface of the tray.
It i~ also expedient that the ratio of the total net area of the perforations in the froth retainer and that of the perforations in the trag i~ 1.2-3Ø This ratio provid-es for a dependable self-instituted control of the froth 12~4~85 layer when the liquid overflows from one call to ~nother.
It is further expedient that the height of the froth retsiner i~ 0.6-1.0 time the distance between two trays, provided the apparatus has more than one tray.
The froth retainer standing as high as that provides for an effective operation of the mas~-transfer apparatu~
over a wide range o~ gas floYJ rate~.
In small-diameter apparatus, the froth retainer can extend over the entire distance ~eparatin~ tvJo adjacent trays. In lar~e-diameter apparatus, it is practical that the height of the froth retainer i6 some~Jhat smaller than the di~tance between the tray~. An unobstructed ~pace ~o formed permits a redi~tribution of the ~as (vapour) flow to take place before the gas reaches the above-lying trsy.
It is preferred that at least two diagonal baffle plates located crosswise one above the other are provided in every cell of the froth retainer, the height of every baffle plate equalling at least one half of the length of a cell side.
The liquid striking against a baffle plate spread~
thereover and i~ deflected towards cell walls so that no azialwise splashing is brought about. The proce~s is re-peated at a ~uperimposed cruciform baffle plate which en-hances the spla~h-depressing effect. A steady froth stabi-lity is the outcome even in large cell~.
It is also preferred that at least one cruci~orm baf-fle plate is provided in every cell, with the height of this baffle plate equalling at lea~t one half of the length
The invention relate~ to chemical and petroleum en-gineering and has specific reference to mas~-tran~fer appa-ratu~.
The invention can be of utility in Yarious installa-tions for heat and mas~ tran~fer ~etween a liquid ~nd a ga9 which find applicatio~ in the chemicalj gas, petroleum ri-fining, metallurgical and ~ood indu~trie~ as well as in oth-er field~. rrhe apparatu~ di~clo~ed can cope with the proces~-e~ o~ absorption, fractination, desorption and ~as scrubb-ing.
The invention holds out ~pecial promise as an item of the equipment of gas-procesaing plant~ and separate in~talla-tions u~ed in the oil and gas industry for treating natural ga~ aLd condensate preparatory to conveying over long dis-tance B -Cryogenic ~ir-separation plant~ is a prO~peCtiVe field of application of the invention.
A sharp increase in the capacity and ef~ectivenes~ of mass-tran~er columns i~ a problem nowaday~. The point i8 that the bubble trays of the traditional de~ign u~ed in these columns do not permit the flow rate of gas or vapour through the net cross-~ectional area of a column to be in-creased oYer a given minimum, which i8 1.2-1.5 mJs for an air-water system under the atmospheric conditions. The prob-lem i~ coped with by increasing the diameter of ma~s-trans-fer apparatus which can be a~ large as 3 to 12 m in high--capacity in~tallations.
Thi~ approach iB, however, unacceptable for drilling ships and offshore rigs where ~pace is at premium.
Xnown in the art i~ a ma~-tran~fer apparatus for ga~-to-liquid contact in the ca3e whereof there are contained one perforated tray, or several ~uch tray~, Qnd a sprayer (cf. Pozin ~.E. "Pennye ~azoochi~titeli, teploobmenniki 1 absorbery", Ieningrad, 1959, p. 51).
A liquid fed from the ~prayer forms a layer of mobile froth on the tray to ab~orb certain gases or dust from the bulk gas flow.
The capacity of the known apparatu~ is low, for the flow rate of the gas through the net cross-aectional area theIe-of is slow, commonly not over 2 or 2.3 m/8, and the layer of froth on the tray i8 thin (around 100 mm).
Any attempt to boost the capacity gives ri~e to tur-bulence which leaves some portions of the tray uncovered with the froth, permittin~ some of the gas to pass through the tray unprocessed. This reduce~ the effectivene~a of the apparQtus.
Also known is a mass-tran~fer apparatue which, in addi-tion to heat and mass tran~fer, can cope also with the wet 8crubbing of gase~ (cf. USSR Inventor'~ Certi~icate No. 434,969, Int. Cl. B01 d 47/04). The ca~e of the known apparatus contains perfor~ted tray~ each whereo~ is ~itted with a contiguous froth retainer in the form of a grid made up of upright barA. The height of ever~ bar i8 0.2 to 0.6 time the thickne~ of the froth layer, and the net cross-~X64;~85 -eectional area of a grid is at lea~t 0.8 time the net eros3-_eectional area of the apparatus. 2erforation~ are provided in some of the bsrs of the froth retainer, next to the sur-face of the tray.
The main purpose the froth retainer is to set up on the tray a thick and ho~ogenous layer of froth vJith fine cellular ~tructure and to pro~ide for a continuous flow of the phases at their interface without spparent fluctuation~.
In other ~Jord~, the ~roth retainer eliminate turbulence and, con~equently, increase the capacity of the apparatus.
Ho~ever, the effectiveness of the process of heat and mas~ transfer taking place in the known apparatus at the gas flow rates over 2.6 to 3.0 m/~ iB low (for the air-water syRtem under the atmo~pheric conditions). Intermittent eddi-e~ brou~ht about at the top of the froth layer expel eome of the liquid from grid cells along the axes thereof, render-ing this portion ineffective as a medium for an active mass transfer or dust recovery. An accompanying splashing im-pair~ the capacity of the apparatu~ and the effectivenes~ of ma~ transfer proce~ses.
The perforations in the lower portion~ of some bars of the froth retainer cannot provide for a u~iform di~tri-bution of the liquid flow over the entire surface of the trsy.
The main object of the inYention i~ to provide a ma~e-transfer apparatu~ a froth retainer whereof i8 deBigned ao as to increase both the capacity and the ef~ecti~eneee of the apparatus, uniformly distribute the liquid in the form of a froth with fine cellular structure over the en-64~ 85 tire surface of ~ tray and prevent splQ3hing of the liquidalong the a~es of grid cells should the g~ flow rate be speeded up.
~he essence of the invention consists in that in a mas~--transfer spparatu~ in the ca~e whereof there are contained at least one horizontal perforated tray and a froth retain-er in the forn of a grid made up of upright bars which are fitted directly to the tray and form intercom~ected cells, according to the invention the lower portions of the bar~
of the froth retainer are made solid and the cell~ of the grid communicate with one another by way of perforations in the upper portions of the bars of the froth retainer.
The perforations flowing wherethrough from one cell to another i~ the froth exercise a self-instituted flow control owing whereto the liquid ie uniformly distributed over the relatively great area of the tray. The ~olid por-tions of the foam retainer bar~ ~erve the same purpo~e as well, preventing undesired accumulations of the liquid in depre~sions or at obliquities of the tray.
It is expedient that the solid portions of the bar~
of the froth retainer are of a height which is 0.1 to 0.5 time the overall height of these bars.
~ his plan is conducive to a u~iform distribution of the froth layer over the entire surface of the tray.
It i~ also expedient that the ratio of the total net area of the perforations in the froth retainer and that of the perforations in the trag i~ 1.2-3Ø This ratio provid-es for a dependable self-instituted control of the froth 12~4~85 layer when the liquid overflows from one call to ~nother.
It is further expedient that the height of the froth retsiner i~ 0.6-1.0 time the distance between two trays, provided the apparatus has more than one tray.
The froth retainer standing as high as that provides for an effective operation of the mas~-transfer apparatu~
over a wide range o~ gas floYJ rate~.
In small-diameter apparatus, the froth retainer can extend over the entire distance ~eparatin~ tvJo adjacent trays. In lar~e-diameter apparatus, it is practical that the height of the froth retainer i6 some~Jhat smaller than the di~tance between the tray~. An unobstructed ~pace ~o formed permits a redi~tribution of the ~as (vapour) flow to take place before the gas reaches the above-lying trsy.
It is preferred that at least two diagonal baffle plates located crosswise one above the other are provided in every cell of the froth retainer, the height of every baffle plate equalling at least one half of the length of a cell side.
The liquid striking against a baffle plate spread~
thereover and i~ deflected towards cell walls so that no azialwise splashing is brought about. The proce~s is re-peated at a ~uperimposed cruciform baffle plate which en-hances the spla~h-depressing effect. A steady froth stabi-lity is the outcome even in large cell~.
It is also preferred that at least one cruci~orm baf-fle plate is provided in every cell, with the height of this baffle plate equalling at lea~t one half of the length
2 64~ ~5 of a cell ~ide.
The cruciform baffle plate ~uppresse~ the spla~hing better than a diagonal one does, providing for an increaee in the capacity of the ma~s-transfer apparatu~. This is achievable by increasing either the size of cells or the gas (vapour) flow rate, without changing the size of cell~
in this latter case.
It i~ further preferred that the ba~fle platea in the cells are perforated.
The perforated baffle plates have a better showing than solid onee in suppressing the splashing and l~eeping up the froth i~ the cells. Their performance permit~ the flow rate of gas or vapour to be increased in the appara-tus.
A preferred embodiment of the invention will now be described by way of an example with reference to the accom-panying drawings in which Fig. 1 ie a sectional elevation of the apparatu~ ac-cording to the invention;
Fig. 2 is an axonometric view of a froth retainer;
Fi~. 3 iB a sect~onal elevation of a cell of a froth retainer showing a cruciform baffle plate at the top and two diagonal ba~fle plates below it;
Fig. 4 is a seotion on line IV-IV of Fig. 3;
Pig. 5 is an axonometric view of a diagonally-srrang-ed cruciform baffle plate in a cell;
Fig. 6 is an axonometric view of two diagonal baffle plates located a distance apart.
12~fiS
Referring to Fig. 1, a caee 1 of the mass-transfer ap-paratu~ of a rectangular or circular eection is fitted with ga~ inlet and outlet pipe~ 2, 3 and a union 4 through which spent liquid leave~ the apparatus. A sprayer 5 i~ located in the case 1 abo~e a horizontal perforated tray 6 formed and kept up whereon is a l~yer of froth. The perforated tray 6 is made up either of perforated sheets or separate tu~e~
(rods) whic~l form a regular grid. A froth retainer 7 made up of up-right bars 8 con~tituing a grid with ce 119 9 is fitted directly to the tray 6.
A length C of a side of the ~quare cell 9 is 0.08--0.25 time a height B of the cell side.
IhR maa~-transfer apparatus of Fig. 1 is fitted with two trays but, according to the invention, there can be on-ly o~e tray or more than t~o trays. In an apparatu~ with two or more trays, the height ~ of the froth ret~iner 7 is 0.6--1.0 time a di~tance H between two adjacent tray~ 6.
Referring to Fig. 2 which i8 an a~onometric view of a froth retainer 7, the cell~ 9 thereof communicate with one another via perforations 10 provided at the top of the bars 8, whereas the lower portions of the bars 8 (Fig. 3) are made solid. A height F of the solid portion of every bar 8 i~ 0.1-0.5 time the height B of the bar 8.
~ he way the perforations 10 are arra~ged in the bars 8 of the froth retainer 7 is shovln in detail in Fig. 3 which is a sectional elevatlon o~ the cell 9. ~he number and diameter of the perforations 10 are selected 80 that the ratio of the total net area of the perforations 10 i~
12~4X~s - ~ -the froth retainer 7 and that of the perforations in the tray is 1.2-3Ø
h cruciform baffle plate ll formed by bars 12, 13 which run parallel with the bars 8 of the froth retainer 7 is fit-ted at the top of the cell 9.
Diagonal baffle plates 14,15 are fltted below the cruciform baffle plate ll and a di~tance apart ~rom each other.
Fig. 4 illustratea a version of the cruciform baffle plate 11 the bar~ 12, 13 whereof are secured parallel with the bar~ 8 (Fig. 1) of the froth retainer 7.
Fig. 5 illustrate~ diagonal ba~fle plates 14, 15 which are located in the cell 9 (shown in light lines) of the froth retainer 7 out of contact with one another. However, diagonal bsffle plate~ located in contact with one another pro~ide a possible alternative.
Fig. 6 illustrates a veraion of a cruciform baffle plate 16 with diagonal bars 17~ 18 located inside a cell 9 (~ig. l~ of the froth retainer 7 shown in light lines.
Cruciform baffle plates located parallel with the bars of the froth retainer (Fig. 4~ and those coincidi~g with the diagonals of the cell (Fig. 5) are of e~ual value as far as their per~ormance is conc~rned. The optio~ depends on the process of manufacturing the froth retainers.
The baffle plates shown in Fig~.-3 through 6 are made of ~olid bars but perforated baffle plates ca~ be used as well. In this latter case they are not only lighter but more effective as means of chec~ing the ~plashing of liquid ~2~XBS
in the cells, providin~ for good performance of the mass-tran~fer apparatus at maximum gas flo~ rates.
In operation, the ga~ or vspour admitted through the pipe 2 pasæes through the perforated tray 6, contacting there the liquid fed through the sprayer 5.
A layer of froth formed on the tray ~ due to the agita-tion of the liquid by the ga~ i8 of fine cellular ~tructure owing whereto the processe~ of heat and mass transfer, and also of ga~ scrubbing, go on at a high rate. ~he 6crubbed gas leaves the apparatu~ through the pipe 3 and the liquid, through the union 4.
~ luctuation~ in the depth of the liquid on the tray 6 due to non-uniform feeding thereof are off~et due to the circulation of the liquid between the cell~ of the froth re-tainer 7.
If the trays used are of a large diameter it iB prac-tical to provide a free space above the froth retainer to uniformly supply the gas to the above-lying trag. In small-diemeter mass-tran~fer apparatus, the froth retainer can ex-tend through the total distance between two adjacent trays.
The diagonal or cruciform baffle plates provided inside the cells of the froth retainer control the turbulence at the centre~ of the cell~, whi~h gives rise to splashing,snd promote the ~tability of the layer of froth. Perforated baf-fle plates are particularly effective in thi~ respect, re-t~ining and redi~tributing the froth in a better way than their solid counterparts. The apparatus with perfor~ted d~-agonal or cruciform baffle plate~ in the cells of the froth - .
12642~35 retainer operate at a maximum gas (vapour) flow rate which cannot be achieved in mass-transfer apparatus featuring froth retainers of any other de~ign.
The disclo~ed mas~-transfer apparatus provideR solution to the problem of increasing 1.5 to 2 times the capacity of absorption and desorption pla~lts, fractination units and gas scrubbin~ equipment.
Apart from that, the disclosed apparatus improves pro-duct purity owing to a high effectivene~s of the mechani~m of heat and ma~s tran~fer therein.
~ he pre~ent invention is conducive to increasing the capacity of the mass-transfer colum~, ~hich i~ the key item of a mass-transfer inEtallation, and pave~ the way to deve-loping compact plants ~ith a large capacity per unit volume.
The invention can be used to advantage in the chemical, pe-trochemical, food, oil and gas industires to cope with ma~s--transfer proces~es.
A preferred field of its application comprises de-etha-nizers and ~tabilizers for processing condensate, high-pres-sure absorbers for treating natural ga~, fractination cOlUmn8 used in the manufacture of synthetic rubber, cryogenic air-_separation plants and gas scrubbers.
The cruciform baffle plate ~uppresse~ the spla~hing better than a diagonal one does, providing for an increaee in the capacity of the ma~s-transfer apparatu~. This is achievable by increasing either the size of cells or the gas (vapour) flow rate, without changing the size of cell~
in this latter case.
It i~ further preferred that the ba~fle platea in the cells are perforated.
The perforated baffle plates have a better showing than solid onee in suppressing the splashing and l~eeping up the froth i~ the cells. Their performance permit~ the flow rate of gas or vapour to be increased in the appara-tus.
A preferred embodiment of the invention will now be described by way of an example with reference to the accom-panying drawings in which Fig. 1 ie a sectional elevation of the apparatu~ ac-cording to the invention;
Fig. 2 is an axonometric view of a froth retainer;
Fi~. 3 iB a sect~onal elevation of a cell of a froth retainer showing a cruciform baffle plate at the top and two diagonal ba~fle plates below it;
Fig. 4 is a seotion on line IV-IV of Fig. 3;
Pig. 5 is an axonometric view of a diagonally-srrang-ed cruciform baffle plate in a cell;
Fig. 6 is an axonometric view of two diagonal baffle plates located a distance apart.
12~fiS
Referring to Fig. 1, a caee 1 of the mass-transfer ap-paratu~ of a rectangular or circular eection is fitted with ga~ inlet and outlet pipe~ 2, 3 and a union 4 through which spent liquid leave~ the apparatus. A sprayer 5 i~ located in the case 1 abo~e a horizontal perforated tray 6 formed and kept up whereon is a l~yer of froth. The perforated tray 6 is made up either of perforated sheets or separate tu~e~
(rods) whic~l form a regular grid. A froth retainer 7 made up of up-right bars 8 con~tituing a grid with ce 119 9 is fitted directly to the tray 6.
A length C of a side of the ~quare cell 9 is 0.08--0.25 time a height B of the cell side.
IhR maa~-transfer apparatus of Fig. 1 is fitted with two trays but, according to the invention, there can be on-ly o~e tray or more than t~o trays. In an apparatu~ with two or more trays, the height ~ of the froth ret~iner 7 is 0.6--1.0 time a di~tance H between two adjacent tray~ 6.
Referring to Fig. 2 which i8 an a~onometric view of a froth retainer 7, the cell~ 9 thereof communicate with one another via perforations 10 provided at the top of the bars 8, whereas the lower portions of the bars 8 (Fig. 3) are made solid. A height F of the solid portion of every bar 8 i~ 0.1-0.5 time the height B of the bar 8.
~ he way the perforations 10 are arra~ged in the bars 8 of the froth retainer 7 is shovln in detail in Fig. 3 which is a sectional elevatlon o~ the cell 9. ~he number and diameter of the perforations 10 are selected 80 that the ratio of the total net area of the perforations 10 i~
12~4X~s - ~ -the froth retainer 7 and that of the perforations in the tray is 1.2-3Ø
h cruciform baffle plate ll formed by bars 12, 13 which run parallel with the bars 8 of the froth retainer 7 is fit-ted at the top of the cell 9.
Diagonal baffle plates 14,15 are fltted below the cruciform baffle plate ll and a di~tance apart ~rom each other.
Fig. 4 illustratea a version of the cruciform baffle plate 11 the bar~ 12, 13 whereof are secured parallel with the bar~ 8 (Fig. 1) of the froth retainer 7.
Fig. 5 illustrate~ diagonal ba~fle plates 14, 15 which are located in the cell 9 (shown in light lines) of the froth retainer 7 out of contact with one another. However, diagonal bsffle plate~ located in contact with one another pro~ide a possible alternative.
Fig. 6 illustrates a veraion of a cruciform baffle plate 16 with diagonal bars 17~ 18 located inside a cell 9 (~ig. l~ of the froth retainer 7 shown in light lines.
Cruciform baffle plates located parallel with the bars of the froth retainer (Fig. 4~ and those coincidi~g with the diagonals of the cell (Fig. 5) are of e~ual value as far as their per~ormance is conc~rned. The optio~ depends on the process of manufacturing the froth retainers.
The baffle plates shown in Fig~.-3 through 6 are made of ~olid bars but perforated baffle plates ca~ be used as well. In this latter case they are not only lighter but more effective as means of chec~ing the ~plashing of liquid ~2~XBS
in the cells, providin~ for good performance of the mass-tran~fer apparatus at maximum gas flo~ rates.
In operation, the ga~ or vspour admitted through the pipe 2 pasæes through the perforated tray 6, contacting there the liquid fed through the sprayer 5.
A layer of froth formed on the tray ~ due to the agita-tion of the liquid by the ga~ i8 of fine cellular ~tructure owing whereto the processe~ of heat and mass transfer, and also of ga~ scrubbing, go on at a high rate. ~he 6crubbed gas leaves the apparatu~ through the pipe 3 and the liquid, through the union 4.
~ luctuation~ in the depth of the liquid on the tray 6 due to non-uniform feeding thereof are off~et due to the circulation of the liquid between the cell~ of the froth re-tainer 7.
If the trays used are of a large diameter it iB prac-tical to provide a free space above the froth retainer to uniformly supply the gas to the above-lying trag. In small-diemeter mass-tran~fer apparatus, the froth retainer can ex-tend through the total distance between two adjacent trays.
The diagonal or cruciform baffle plates provided inside the cells of the froth retainer control the turbulence at the centre~ of the cell~, whi~h gives rise to splashing,snd promote the ~tability of the layer of froth. Perforated baf-fle plates are particularly effective in thi~ respect, re-t~ining and redi~tributing the froth in a better way than their solid counterparts. The apparatus with perfor~ted d~-agonal or cruciform baffle plate~ in the cells of the froth - .
12642~35 retainer operate at a maximum gas (vapour) flow rate which cannot be achieved in mass-transfer apparatus featuring froth retainers of any other de~ign.
The disclo~ed mas~-transfer apparatus provideR solution to the problem of increasing 1.5 to 2 times the capacity of absorption and desorption pla~lts, fractination units and gas scrubbin~ equipment.
Apart from that, the disclosed apparatus improves pro-duct purity owing to a high effectivene~s of the mechani~m of heat and ma~s tran~fer therein.
~ he pre~ent invention is conducive to increasing the capacity of the mass-transfer colum~, ~hich i~ the key item of a mass-transfer inEtallation, and pave~ the way to deve-loping compact plants ~ith a large capacity per unit volume.
The invention can be used to advantage in the chemical, pe-trochemical, food, oil and gas industires to cope with ma~s--transfer proces~es.
A preferred field of its application comprises de-etha-nizers and ~tabilizers for processing condensate, high-pres-sure absorbers for treating natural ga~, fractination cOlUmn8 used in the manufacture of synthetic rubber, cryogenic air-_separation plants and gas scrubbers.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A mass-transfer apparatus in the case whereof there are contained at least one horizontal perforated tray and a froth retainer in the form of a grid made up of vertical bars which are fitted directly to the tray and form interconnected cells, where-in the lower portions of the bars of the froth retainer contigu-ous with the tray are made solid and the cells of the grid com-municate with one another by way of perforations in the upper portions of the bars of the froth retainer.
2. A mass-transfer apparatus as in claim 1, wherein the height of the solid portion of the bars of the froth retainer is 0.1-0.5 time the height of the bars of the froth retainer.
3. A mass-transfer apparatus as in claim 1 or 2, wherein the ratio of the total net area of the perforations in the froth retainer and that of the perforations in the tray is 1.2-3Ø
4. A mass-transfer apparatus as in claim 1, wherein the height of the froth retainer is 0.6-1.0 time the distance between two adjacent trays, provided the apparatus has two or more trays.
5. A mass-transfer apparatus as in claim 1, wherein at least two diagonal baffle plates located crosswise one above the other are provided in every cell of the froth retainer, the height of every baffle plate being equal to at least one half of the length of a cell side.
6. A mass-transfer apparatus as in claim 1, wherein at least one cruciform baffle plate is provided in every cell of the froth retainer, the height of this baffle plate being equal to at least one half of the length of a cell side.
7. A mass-transfer apparatus as in claim 5 or 6, wherein the baffle plates in the cells are perforated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000509638A CA1264285A (en) | 1986-05-21 | 1986-05-21 | Mass-transfer apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000509638A CA1264285A (en) | 1986-05-21 | 1986-05-21 | Mass-transfer apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1264285A true CA1264285A (en) | 1990-01-09 |
Family
ID=4133174
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000509638A Expired - Fee Related CA1264285A (en) | 1986-05-21 | 1986-05-21 | Mass-transfer apparatus |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1264285A (en) |
-
1986
- 1986-05-21 CA CA000509638A patent/CA1264285A/en not_active Expired - Fee Related
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| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |