Process for producing purified synthesis gas from soot-containing synthesis gas having a temperature of at least 5 °C above its dew point comprising the steps of (a) cooling the soot-containing synthesis gas to a temperature below its dew point by indirect heat exchange in a shell-tube heat exchanger without removing the condensate formed, thereby forming a synthesis gas/condensate mixture; and (b) contacting the synthesis gas/condensate mixture with a scrubbing liquid to remove the condensate resulting in a purified synthesis gas and used scrubbing liquid, wherein the soot-containing synthesis gas in step (a) is passed through the shell-tube heat exchanger at the tube side.