GB1340195A - Separation and removal of selected gas components from gaseous mixtures - Google Patents

Abstract

1340195 Ion pumps; discharge treatment of gases O NIGOL 22 June 1971 [22 June 1970] 30269/70 Headings H1D and H1X A selected gas component is separated and removed from a gaseous mixture, at least one component of which is an electronegative gas, by passing the gaseous mixture as a stream between a pair of electrodes, namely a cathode 2 and an anode 1, ionizing a component of the gaseous mixture, producing an electric field between the electrodes whereby to induce a flow of gas towards a respective one of the electrodes, producing a chemically reactive surface to intercept such flow, and reacting said selected gas component with the said surface. Ionization may be effected by a supply of free electrons provided by negative corona, by heating the cathode, or by irradiating the gas with an ionizing radiation, or by a supply of positive ions provided by positive corona, by heating the anode, or by irradiation. The chemically reactive surface may be a film of liquid, e.g. an aqueous solution of sodium hydroxide or a very dilute aqueous solution of glacial acetic acid when removing SO 2 from flue gas. In the device shown, the anode 1 is a cylinder of stainless steel extending between cylindrical housings 3 and 4 and surrounding an axial cathode 2 of twisted nickel-chrome ribbon suspended between brass bead end shields 16 and 17 connected to terminals 9 and 14 by wires 18 and 20. Wire 18 is connected to a tensioning device 19 and wire 20 is surrounded by an insulator 15. Flue gas passes through the device between an inlet 13 and an outlet 8. Liquid supplied through a pipe 22 to a reservoir 21 spills over the upper end of the anode and flows down the inner surface of the latter to a collecting reservoir 23 from which it is removed via a drain connection 24. In an alternative arrangement (Figs. 3 and 4, not shown) designed to handle larger quantities of gas, a plurality of anode plates and cathode wires are suspended across a duct of rectangular cross-section having metal walls which are connected to the anode plates.