GB1196610A - Purification of Gases - Google Patents

Abstract

1,196,610. Purifying combustible gas. LUMMUS CO. 11 Oct., 1967 [11 Oct., 1966], No. 46498/67. Heading C5E. [Also in Division B1] Gas streams, such as synthesis gas or natural gas, which are rich in hydrogen and hydrocarbons, are purified to remove carbon dioxide and hydrogen sulphide therefrom by contact with a solvent composition comprising (a) an organic solvent in which carbon dioxide is soluble at 25‹ C. and 1 atmosphere pressure to the extent of at least one volume per volume of solvent, which boils at at least 150‹ C. at atmospheric pressure, which is unreactive with amines, and which contains at least one oxygen-, nitrogen- or sulphur-containing functional group, suitably as the hetero-atom of a heterocyclic compound, such functional groups being present in greater number in the molecule than the number of hydroxyl groups present if the molecule contains more than one hydroxyl group, and (b) a secondary monohydric alkanolamine, suitably N-methyl or N-ethyl ethanolamine, (a) is suitably a cyclic or acyclic ether, a glycol ether, a dioxolane, a dioxane, a furan, a trioxane, an oxazole, a sulphone, a sulphoxide, a pyrrole or a purrolidone, but most preferably is sulpholane (tetrahydrothiophene-1,1-dioxide) or 2,2 - dimethyl - 4 - hydroxymethyl - 1,3- dioxolane. Generally 0À1-10 mols. of (b) are used per mol. of (a), and preferably (b) is present in a concentration of 2À5-5N with respect to (a).