Producing pure gas of high calorific value from gasification of solid fuel

Claim 1

A process of producing and then using a gas of high calorific value and low dust content comprising contacting a solid fuel with water vapor and free oxygen in a gasification reactor 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 8 grams of dust per standard cubic meter and having a temperature of about 350° to 800° C., subjecting the gas to a dry coarse purification to reduce the solids content thereof, intensely scrubbing the gas at about 150° to 350° C. with a scrubbing liquid predominantly comprising hydrocarbons and including less than 2% of water by weight, after said dry coarse purification and before said scrubbing spraying water into the gas thereby to cool it to below 350° C. so as to prevent cracking of constituents of said scrubbing liquid, at least about 70% of said hydrocarbons of the scrubbing liquid having a boiling point above about 350° C., said scrubbing liquid being supplied to the scrubbing stage at a rate of about 0.5 to 6 liters per standard cubic meter of raw gas, withdrawing a purified gas with a solids content not exceeding 10 milligrams per standard cubic meter and having an enhanced calorific value and employing it as a fuel for the operation of at least one turbine, withdrawing used scrubbing liquid from said intense scrubbing stage and cooling it by indirect heat exchange in a cooling zone, separating the liquid from said cooling zone in a tar separator into a high-solids heavy phase and a low solids lighter phase, and using said lighter phase as said scrubbing liquid in the intense scrubbing stage.