GB913361A - Improvements in or relating to gas washing towers - Google Patents

Abstract

913,361. Contacting gases with liquids. STILL, K. F., [trading as STILL, C. [Firm of]]. April 24, 1959, No. 14164/59. Class 55 (2). An apparatus for washing gases comprises a tower through which, in use, the gas and the washing liquid flow in countercurrent. A plurality of sections wherein gas and liquid are mixed are spaced along the length of the tower, each section including a floor having means for deflecting gas flow through that floor the deflecting means including a multiplicity of deflecting devices, at least a portion of each device being inclined relative to the longitudinal axis of the tower, the devices being disposed over the cross-sectional area of the tower in such manner that collectively they deflect gas flow through them into a multiplicity of paths distributed over the cross-sectional area of the tower, each path inclined to the longitudinal axis of the tower, the floor also having means disposed over the cross-sectional area of the tower which permits the passage of liquid and distributes such liquid over the cross-sectional area of the tower. In Fig. 1, liquid enters cylindrical tower 1 via supply pipe 3 and sprinkler 2 and leaves the foot of the tower at 4. Pipes 5 and 6 are the gas inlet and outlet respectively. Inside the tower are a plurality of plates 8 through which pass a series of pipes 9 arranged in concentric rings about the centre of the plate. Liquid collecting on the plates 8 passes through slots 10 into the pipes 9 (see Fig. 2) and falls via funnels 11 on to baffle plates 15, by means of which it is sprayed on to the next lower plate. Each pipe 9 also allows the upward passage of the gas and has a gasflow-deflecting mouthpiece 16 at the top. The deflector mouthpieces 16 of any one ring of pipes 9 deflect the gas flow through the mouthpiece tangentially in the same rotational sense, the mouthpieces of adjacent rings of pipes 9 deflecting gas flow in opposite rotational senses. Alternative constructions of pipe 9 are shown, including that of Fig. 5. Pipes 9 can also be replaced by perforations with depending pipes 33 as shown in Fig. 14, while pipes 33 may be bent in various ways. In Figs. 21, 23 and 25, each plate 8 is replaced by plate 47 comprising a number of channels 48, 49, all of which have overflow slots 51 or apertures 50. Above each plate 47 are mounted at least three annular channels 40, 41, 42. Each channel has outlet for the liquid and the diameter of the inner edge of each channel is a little smaller than, or equal to, that of the outer edge of the next lower channel. Between these channels, rings of guide vanes 43, 44 are arranged in such a manner that the upper ring of guide vanes 43 imparts a rotary motion to the gas about the vertical axis of the tower, the direction of rotation being opposite to that imparted by the lower ring of guide vanes 44. The lowest annular channel 42 is joined to a vertical pipe 45 located in the centre of the tower, which pipe leads the liquid to cup 46, from whence it overflows to plate 47. This plate distributes the liquid uniformly across the entire cross-section of the tower, liquid from plate 47 raining down on to the next set of channels 40, 41, 42 below. In general it will be necessary to pass the gas through a separator device, either shortly before it leaves the tower or after it has left the tower, in order to separate any liquid droplets therefrom. In Fig. 26, liquid is fed into tower 1 through line 64 and on to the uppermost plate 8 with its pipes 9. Gas rising through the pipes 9 in the uppermost plate 8 passes through apertures 66 in a plate 60 and is given a tangential motion, substantially parallel to plate 60, by means of helically curved tubes 67. Any particles of liquid entrained in the gas are deposited on the walls of the tower, flow down the walls to plate 60 and then run down pipe 68 to the uppermost plate 8. Ring 70, provided on the walls of the tower, intercepts any remaining droplets of liquid. The gas passes through orifice 61 into pipe 63 and thence to outlet 6. An alternative separator device is the basket 75 of Fig. 28, having perforated conical double walls 76, 77. A further alternative is the basket 85 of Fig. 30, this being located outside the tower 1 and having perforated conical double walls 88, 89. Instead of basket 85, there may be used the pipe 95 of Fig. 31, which pipe is slotted at 96 and carries guide vanes 97.