Patent ID: 8048178

Claim:
A process for producing a purified synthesis gas stream from a carbonaceous feedstock, the process comprising the steps of (a) partial oxidation of the carbonaceous feedstock with a molecular oxygen comprising gas to obtain a synthesis gas comprising water, hydrogen sulphide, and carbon dioxide besides the main constituents carbon monoxide and hydrogen, (b) mixing the synthesis gas and methanol and reducing the temperature of said mixture and separating a liquid methanol-water mixture from a cooled gaseous synthesis gas, (c) contacting the cooled synthesis gas obtained in step (b) with methanol to decrease the content of hydrogen sulphide and carbon dioxide in the synthesis gas, thereby obtaining a rich methanol stream comprising hydrogen sulphide and carbon dioxide and a synthesis gas stream depleted in hydrogen sulphide and carbon dioxide, (d) regenerating the rich methanol stream of step (c) by separating from the rich methanol a carbon dioxide fraction and a hydrogen sulphide fraction to obtain lean methanol, which lean methanol is used as methanol in step (b) and/or (c), and wherein (e) part of the methanol in the methanol-water mixture obtained in step (b) is isolated and reused in step (b) and (c) and wherein, (f) another part of the methanol in the methanol-water mixture obtained in step (b) is recycled to step (a) under conditions such that methanol is converted into carbon monoxide and hydrogen.