GB523845A - Method of recovering sulphur dioxide - Google Patents

Abstract

523,845. Recovering sulphur dioxide. GUGGENHEIM, M., GUGGENHEIM, S. R., SMITH, E. A. C., and WHELPLEY, M. G. B. [trading as GUGGENHEIM BROS.] Jan. 16, 1939, No. 1467. Convention date, Jan. 17, 1938. Drawings to Specification. [Class 1 (ii)] In the recovery of sulphur dioxide from gases by contacting the gases with an absorption liquid containing dimethyl aniline, heating the absorption liquid to liberate the sulphur dioxide and collecting the liberated sulphur dioxide, a series of pools of the absorption liquid are formed by flowing the absorbent down through an apparatus of the bubble-plate tower type, the gases are passed upwardly through the pools of liquid at atmospheric pressure, and one or more of the pools of liquid are cooled to dissipate the heat developed during the absorption. The cooling may be such that the dimethyl aniline is kept at a temperature below 20‹C. preferably below 15‹C. The waste gases leaving the top of the tower may be washed by a reagent such as sulphuric acid to remove any entrained dimethyl aniline. The solution charged with sulphur dioxide from the bottom of the tower may be preheated by heat exchange with the stripped liquid and then fed to the top of a stripping tower which may be of the packed or bubble plate type. Heat is applied to the base of the stripping tower either by the direct introduction of steam, or by maintaining a body of water or a dilute solution of ammonium or alkali sulphite at the base of the tower and applying heat indirectly. In the latter case the water &c. carried out of the tower by the organic liquid may be separated in a settling tank &c. The sulphur dioxide leaving the top of the stripping tower may be passed first through a condenser and then into contact with sulphuric acid.