GB1203451A - Purification of gases containing sulphur oxide products - Google Patents

Abstract

1,203,451. Purifying combustion gases. WEIR PUMPS Ltd. 7 July, 1967 [20 July, 1966; 8 Feb., 1967], No. 31385/67. Heading B1R. [Also in Division C1] In a process for purifying gases containing sulphur oxides, e.g. combustion gases, the gases are treated at a flow rate and temperature by injecting thereinto an amount of an alkaline substance such that the sulphur oxides are converted into a sulphite and/or bi-sulphite, the thus treated gases being then scrubbed to remove the sulphite and/or bisulphite without decomposition thereof. Ammonia is the preferred alkaline substance and the temperature of the gases when the alkaline substance is injected is between 10‹ and 180‹C., preferably 50‹ to 150‹C. The scrubbing agent may be water at a temperature of the order of 50‹C. The amount of alkaline substance added may be close to that stoichiometrically necessary to produce a sulphite or that necessary to produce a bi-sulphite. As shown in Figure 1 a gas at 150‹C is sprayed with an alkaline substance from nozzles 2 in a conduit 1 and is afterwards scrubbed in a vessel 4 by passage through a thin layer of liquid maintained on a perforated plate 7. Scrubbing liquid is supplied at 11 and withdrawn via overflow 14 and the sump 6. In a modified apparatus for carrying out the process a chamber may be interposed between the point of introduction of the alkaline substance and the scrubbing vessel. This intermediate chamber may contain heat-exchange elements and condensate collecting in the chamber may be reintroduced into the gas entering through conduit 1. Liquid drawn off from the layer of liquid on plate 7 may be mixed with such condensate.