GB421970A - Improvements in or relating to the removal of hydrogen sulphide from gases or liquids - Google Patents

Abstract

Alkaline liquors, e.g. aqueous sodium or potassium carbonate, which have been used for scrubbing gases or vapours containing hydrogen sulphide are freed from hydrogen sulphide in a three stage process which comprises treating the fouled liquor with carbon dioxide, boiling the so treated liquor, and finally treating the thus regenerated liquor to remove the hydrogen sulphide still contained therein. The liquors may be thereafter returned to the scrubbing step. The regenerated liquors may be treated in the third stage with an oxidising agent such as a peroxide or by aeration with air or oxygen in the presence of a catalyst. The peroxide may be hydrogen peroxide or a peroxide of an alkali or alkaline earth metal, e.g. barium or sodium peroxide. These peroxides may be added to the liquors in the form of a solution or fine suspension in successive small quantities with agitation. Alternatively, the liquor may be passed through a bed of catalyst with simultaneous aeration in the third stage. The catalyst may consist of a mixture of the hydroxides of iron and chromium precipitated together on a support such as coke. The examples relate to the regeneration of aqueous potassium carbonate solutions used in scrubbing coal gas. The first Provisional Specification describes also the general application of peroxides for the removal of small quantities of hydrogen sulphide from liquids such as regenerated scrubbing liquors or gas holder water.ALSO:The first Provisional Specification describes the use of peroxides, e.g. hydrogen, sodium or barium peroxide, for the removal of small quantities of hydrogen sulphide from liquids, e.g. gas holder water.