Process for removing CO/sub 2/, H/sub 2/S and other gaseous impurities from gaseous mixtures

A process is disclosed for removing gaseous impurities such as CO/sub 2/ and/or H/sub 2/S from a gaseous mixture obtained by reacting combustible substances with steam, said steam being produced in boilers fed with water previously purified in degassing columns. The gaseous impurities are removed by means of an absorbent solution and the latter is regenerated in a regeneration column by stripping with steam. The stripping steam necessary for the degassing is delivered, at a pressure at least equal to that in the regeneration column, to the degassing columns and then to the regeneration column. The boiler feed water to be purified is previously heated, by supply of residual heats, to a temperature in the vicinity of the boiling temperature of the absorbent solution in the regeneration column.