A method of treating a gas current which is obtained from coal by gasification comprises compressing the gas in several stages and prior to the entrance into a subsequent stage, cooling and separating the liquid from at least a portion of the gas and then heating the cooled and separated gas. The apparatus includes a plurality of compression stages with at least one of the stages having connections to a cooler and a water separator through which the gases pass and including a heater for treating at least the portion of the gas which passed through the cooler and separator and which is then delivered into a conduit for transferring all of the removed gas from the previous stage into a subsequent stage.