CN2669950Y

CN2669950Y - Open overflow device

Info

Publication number: CN2669950Y
Application number: CNU200320122620XU
Authority: CN
Inventors: 姚克俭; 王良华
Original assignee: Zhejiang University of Technology ZJUT
Current assignee: Zhejiang University of Technology ZJUT
Priority date: 2003-12-17
Filing date: 2003-12-17
Publication date: 2005-01-12
Anticipated expiration: 2013-12-17

Abstract

The utility model relates to an open overflow device, comprising an overflow board. Overflow holes are arranged on the overflow board, and the overflow holes arranged on the overflow board are a row of isosceles-trapezoid overflow holes with same size; the upper bottom edge of the isosceles-trapezoid overflow holes is in the same line and is parallel to the upper edge of the overflow board, and the length of the lower bottom of the isosceles-trapezoid overflow holes is 0. 5-1 time than the length of the upper bottom of the isosceles-trapezoid overflow holes; the isosceles-trapezoid overflow holes are bilateral symmetry along the longitudinal center line of the overflow board, and the center distance of two adjacent isosceles-trapezoid overflow holes on the right side and the left side of the longitudinal center line of the overflow board is distributed in manner of equidistance from the longitudinal center line of the overflow board to two ends of the overflow board; the space of the overflow holes is reduced gradually, and the ratio of the adjacent center distance is 1-1. 2. The utility model is provided with the overflow holes, which defers the chocking phenomenon of the downcomer and enhances the liquid flux of the tray for 10 percent-25 percent ; by setting the distribution of the overflow holes, the liquid distribution of the tower board is improved, and the mass-transfer efficiency of the tower board is enhanced for 5 percent-10 percent.

Description

The open type downflow weir

(1) technical field

The utility model relates to a kind of open type downflow weir, is mainly used in various board-like fractionating column, absorption tower and the desorber of industries such as oil refining, chemical industry, petrochemical industry and light industry.

(2) background technology

The tower that is used for gas-liquid mass transfer mainly contains plate column and packed tower, and plate column can be divided into again downspout and no downspout two classes.Tradition has the structure of downspout tower tray shown in accompanying drawing 4,5, and every mainly contains column plate, downflow weir and downspout by the downspout tower tray and forms.During tower tray work, the bubbling element that gas is offered from column plate is from bottom to top by the liquid layer on the column plate, and liquid flows out the back laterally by column plate from the downspout bottom of last layer column plate, recrosses downflow weir, enter downspout then, gas-liquid is carried out contact mass transfer on column plate.In order to guarantee certain gas liquid film, need on column plate, to keep certain thickness liquid layer, usually downflow weir is set at the column plate liquid outlet.The height of column plate supernatant layer is by overflow height of weir and the decision of overflow crest over the weir.The overflow crest over the weir is by the overflow intensity decision of downflow weir, and overflow intensity is big more, and the overflow crest over the weir is high more.The downspout choking phenomena can take place apart from the distance of tower wall is too small in the too high and downflow weir of liquid layer on the downflow weir, causes the downspout liquid flooding, and whole tower can not normal running.In order to improve liquid flux, should suitably increase downflow weir and increase the distance of downflow weir apart from the tower wall.For tradition the downspout column plate is arranged, increase downflow weir and increase the distance of downflow weir, the bubbling area of column plate is reduced, reduce the ability of gas by column plate apart from the tower wall.

Multi-overflow downspout column plate and square downcomer column plate are doubled and redoubled the downflow weir of tower tray by increasing downflow weir, the overflow intensity that reduces downflow weir reaches the purpose that enlarges liquid flux, but the liquid stream contraction in length of liquid on column plate plate face, reduce the time of contact of gas-liquid on column plate, reduced the mass-transfer efficiency of tower tray.Patent 97107085.7 is mentioned a kind of new tower plate, the cross section that will lean on the overflow ducts of tower wall and downspout is by the arc crescent of changing into, its advantage is: (1) is owing to adopted the crescent downflow weir, falling liquid passage area occupied dwindles, make non-mass-transfer zone shared area on the monoblock column plate littler more than 3% than traditional overflow area area, even reach 20%, and effective mass transfer area of column plate is obviously increased, improve the disposal ability of gas; (2) because crescent downflow weir and crescent downspout have certain radian, the liquid on the whole column plate is all flowed equably, there be not " dead band ", liquid macroscopic view flow regime is in comparatively ideal " piston flow " state on the column plate, helps to improve mass-transfer efficiency.(3) because the pipe Caudad tower wall of crescent downspout shrinks, do not have liquid receiving area on the column plate, increased effective mass transfer area of column plate.Analyze from the increase of effective mass transfer area, under the certain situation of tower diameter, the tower tray that the energy force rate of the processing gas of this tower tray is traditional is high by 10 ~ 25%.Also can obtain in theory, this tower tray is because downflow weir is long, the overflow intensity or the overflow crest over the weir of downflow weir are low, but downflow weir is very near apart from the distance of tower wall, the downspout choking phenomena will take place when less overflow intensity or overflow crest over the weir, cause the downspout liquid flooding, thereby for improving the liquid flux DeGrain.By analysis-by-synthesis, the prior art tower tray, its downflow weir structure both was difficult to reach and can improves liquid flux, can improve gas flux and mass-transfer efficiency again.

(3) summary of the invention

In order to solve the shortcoming that choking phenomena takes place existing downflow weir downspout easily, the utility model provides a kind of fluid flow that can pass through the downflow weir various piece by reasonable distribution, reduce the overflow crest over the weir, avoid the open type downflow weir of downspout generation choking phenomena.

The technical solution adopted in the utility model is for this reason:

A kind of open type downflow weir includes overflow weir, offers spout hole on the described overflow weir.

What offer on the described overflow weir is the measure-alike isosceles trapezoid spout hole of a row, and the last base of described isosceles trapezoid spout hole is on a line and parallel with the overflow weir top edge.

The length of going to the bottom of described isosceles trapezoid spout hole is the long 0.5-1 of isosceles trapezoid spout hole upper base times.

Described isosceles trapezoid spout hole is along overflow weir longitudinal centre line left-right symmetry, adjacent two isosceles trapezoid spout hole centre-to-centre spacing of the overflow weir longitudinal centre line left and right sides equidistantly distribute from overflow weir longitudinal center alignment overflow weir two ends, described spout hole spacing reduces gradually, and the ratio of adjacent center distance is 1-1.2.

The height of described isosceles trapezoid spout hole is 0.3-0.8 a times of overflow height of weir, and the upper base of isosceles trapezoid spout hole is long to be the high 0.8-1.5 of isosceles trapezoid times.

The last base of described isosceles trapezoid spout hole and the distance of overflow weir top edge are 0.1-0.3 times of open type overflow height of weir.

The beneficial effects of the utility model are: 1, offer spout hole on the downflow weir of the present utility model, compare with conventional downflow weir, there is 10% ~ 25% liquid to enter downspout by the isosceles trapezoid spout hole, reduced by the liquid flowing strength on the downflow weir, thereby reduced the overflow crest over the weir,, under the identical situation of the distance of tower wall or relative downflow weir, postpone the downspout choking phenomena and take place at downflow weir, improve the liquid flux 10% ~ 25% of tower tray; 2, for the chord downcomer column plate, the utility model is if adjacent isosceles trapezoid spout hole centre-to-centre spacing reduces gradually from overflow weir longitudinal center alignment overflow weir two ends, then to offer the percent opening of isosceles trapezoid spout hole bigger at the downflow weir two ends, and the percent opening of offering the isosceles trapezoid spout hole in the middle of the downflow weir is less, can adjust flow distribution, increase fluid flow by the downflow weir two ends, improve or eliminate the liquid dispersion phenomenon of column plate arch area, improve the liquid distribution on the column plate, improve column plate mass-transfer efficiency 5% ~ 10%; 3, for the square downcomer tower tray of the orthogonal arrangement of square downcomer of adjacent two layers tower tray, because flowing to the flow process at downflow weir middle part to downflow weir two ends, liquid increases gradually, the liquid time of staying onboard of crossing downflow weir also increases to the downflow weir two ends gradually from the downflow weir middle part, influences the column plate mass-transfer efficiency.Because the percent opening of the isosceles trapezoid spout hole that the utility model downflow weir middle part is offered to the downflow weir of downflow weir two ends increases gradually, the liquid that flows through downflow weir increases to two ends gradually from the downflow weir middle part, the time of improving liquid on the plate stops and distributes, and improves column plate mass-transfer efficiency 5% ~ 10%; 4, owing to offer isosceles trapezoid spout hole shunting liquid on the downflow weir of the present utility model, the overflow crest over the weir reduces, when the same liquid flux, it is long to shorten downflow weir, fall the liquid aisle spare, increase the bubbling area, improve gas processing capability and tower tray mass-transfer efficiency; 5, the utility model is simple in structure, and is easy to make, and operating characteristics is reliable.

(4) description of drawings

Accompanying drawing 1 is the open type downflow weir schematic diagram of the utility model chord downcomer

Accompanying drawing 2 is the open type downflow weir schematic diagram of the utility model square downcomer

Accompanying drawing 3 is the structural representation of the isosceles trapezoid spout hole of the utility model open type downflow weir

Accompanying drawing 4 is the schematic diagram of the prior art downflow weir of chord downcomer

Accompanying drawing 5 is the schematic diagram of the prior art downflow weir of square downcomer

(5) specific embodiment

Embodiment 1:

Ethanol-water system, former tower diameter D=1200mm adopts sieve tray 1, single overflow chord downcomer 2, distance between plates H _T=500mm, enclosed overflow height of weir h _w=50mm, the long l of downflow weir _w=848mm.After adopting the utility model open type downflow weir, distance between plates, sieve tray perforate situation, downflow weir are grown all constant, change the enclosed downflow weir into the open type downflow weir, open type overflow height of weir still is 50mm, on the weir plate of open type downflow weir, offer 20 measure-alike isosceles trapezoid spout holes 3, the last base of isosceles trapezoid spout hole is that 20mm, bottom are 10mm, the high 20mm of being, the distance of the last base of isosceles trapezoid spout hole and overflow weir 4 top edges is 15mm, and the centre-to-centre spacing of adjacent two isosceles trapezoid spout holes equates.Measure and show that adopt the disposal ability of the tower of the utility model open type downflow weir to improve 10.8% than former tower, the cat head concentration of alcohol brings up to 93.2% by former 92.8%.

Embodiment 2

Ethanol-water system, former tower diameter D=1600mm adopts sieve tray 1, single overflow chord downcomer 2, distance between plates is H _T=500mm, enclosed overflow height of weir h _w=50mm, the long l of downflow weir _w=1170mm.After adopting the utility model open type downflow weir, distance between plates, sieve tray perforate situation, downflow weir are grown all constant, change the enclosed downflow weir into the open type downflow weir, open type overflow height of weir still is 50mm, on the weir plate of open type downflow weir, offer 22 measure-alike isosceles trapezoid spout holes 3, the last base of isosceles trapezoid spout hole is that 30mm, bottom are 30mm, the high 30mm of being, the distance of the last base of isosceles trapezoid spout hole and overflow weir 4 top edges is 10mm, and the centre-to-centre spacing of adjacent two isosceles trapezoid spout holes equates.Measure and show that adopt the disposal ability of the tower of the utility model open type downflow weir to improve 24.5% than former tower, concentration of alcohol is constant at the bottom of cat head, the tower.

Embodiment 3

The methanol-water system, former tower diameter D=800mm adopts sieve tray 1, single overflow chord downcomer 2, distance between plates is H _T=500mm, enclosed overflow height of weir h _w=45mm, the long l of downflow weir _w=586mm.After adopting the utility model open type downflow weir, distance between plates, sieve tray perforate situation, downflow weir is long all constant, change the enclosed downflow weir into the open type downflow weir, open type overflow height of weir still is 45mm, on the weir plate of open type downflow weir, offer 10 measure-alike isosceles trapezoid spout holes 3, the last base of isosceles trapezoid spout hole is 30mm, the bottom is 20mm, height is 30mm, the distance of the last base of isosceles trapezoid spout hole and overflow weir 4 top edges is 10mm, adjacent two isosceles trapezoid spout hole centre-to-centre spacing of the overflow weir longitudinal centre line left and right sides reduce gradually from overflow weir longitudinal center alignment overflow weir two ends, and the ratio of its adjacent center distance is 1.1.Measure and show that adopt the disposal ability of the tower of the utility model open type downflow weir to improve 18.6% than former tower, the cat head methanol concentration brings up to 99.5% by former 99.0%.

Claims

1. An open overflow weir, comprising an overflow weir plate, characterized in that overflow holes are opened on the overflow weir plate.

2. The open overflow weir according to claim 1, characterized in that: a row of isosceles trapezoidal overflow holes with the same size is opened on the overflow weir plate, and the isosceles trapezoidal overflow holes The upper bottom edge is on a connecting line and parallel to the edge of the overflow weir plate.

3. The open overflow weir according to claim 1, characterized in that: the length of the lower bottom of the isosceles trapezoidal overflow hole is 0.5-1 times the length of the upper bottom of the isosceles trapezoidal overflow hole.

4. The open overflow weir according to claim 2 or 3, characterized in that: the isosceles trapezoidal overflow hole is symmetrical to the left and right along the longitudinal center line of the overflow weir plate, and the left and right sides of the longitudinal center line of the overflow weir plate The distance between the centers of two adjacent isosceles trapezoidal overflow holes on the side is distributed equidistantly from the longitudinal centerline of the overflow weir plate to the two ends of the overflow weir plate, and the distance between the overflow holes decreases gradually. for 1-1.2.

5. The open overflow weir according to claim 4, characterized in that: the height of the isosceles trapezoidal overflow hole is 0.3-0.8 times the height of the overflow weir, and the upper bottom of the isosceles trapezoidal overflow hole The length is 0.8-1.5 times the height of the isosceles trapezoid.

6. The open overflow weir according to claim 4, characterized in that the distance between the upper bottom of the isosceles trapezoidal overflow hole and the edge of the overflow weir plate is 0.1- 0.3 times.

7. The open overflow weir according to claim 5, characterized in that: the distance between the upper bottom of the isosceles trapezoidal overflow hole and the edge of the overflow weir plate is 0.1- 0.3 times.