The invention relates to a process and a device for generating a fuel gas for a gas turbine by separating off sulphur components from a gas mixture containing hydrogen, carbon monoxide, carbon dioxide and also carbonyl sulphide and/or hydrogen sulphide, which gas mixture is in this case scrubbed in a physical gas scrubber with a methanol scrubbing medium at a pressure between 30 and 80 bar(a) in order to obtain a first sulphur-free gas mixture and also a methanol scrubbing medium loaded with sulphur components and carbon dioxide, which methanol scrubbing is then regenerated, wherein a carbon dioxide-rich gas phase that contains sulphur components and is formed by pressure reduction is treated in a further gas scrubber with a methanol scrubbing medium in order to back-wash sulphur components and to generate a second sulphur-free gas mixture.