FIELD: material separation. SUBSTANCE: gas under treatment is cooled to a temperature below the dew point of the water contained in it. The cooling is sufficient for obtaining a flow of condensed water and cooled dewatered gas. The latter is subjected to scrubbing with a liquid absorbent adapted for binding H2S. The scrubbing results in obtaining purified gas and polluted liquid absorbent which is recycled for washing. The gas is rehydrated through bringing into contact with water containing a portion of condensed one and another residual water. The water has a temperature sufficiently high for obtaining rehydrated purified gas which water content is essentially equal to that of the gas under treatment. The purified gas can have some residual water introduced to it. EFFECT: higher efficiency of process and lower cost. 5 dwg
