A process of producing a gas of high calorific value and low dust content comprising contacting coal with water vapor and free oxygen at a pressure of about 5 to 150 bars and a temperature sufficient to produce a gas containing hydrogen and carbon monoxide, containing at least about 10 grams of dust per standard cubic meter and having a temperature of about 350.degree. to 800.degree. C., subjecting the gas to a coarse purification to reduce the solids content thereof, then scrubbing the gas at about 200.degree. to 300.degree. C. with a liquid predominantly comprising hydrocarbons and including less than about 5% of water by weight, and withdrawing a purified gas substantially free of solids and having an enhanced calorific value. In accordance with preferred features, the coarse purification stage includes at least one cyclone separator, the gas leaves the coarse purification stage at a temperature above about 350.degree. C. and is cooled by spraying with water to below 350.degree. C. before entering the intense scrubbing stage.