Process and plant for producing methanol

A plant for producing methanol from an input gas comprising carbon monoxide and hydrogen, comprising:

• a feed conduit for introducing input gas under elevated pressure into a pre-reactor stage, wherein
• the pre-reactor stage is configured for catalytic conversion of the input gas into a first methanol-containing product stream;
• a first separator arranged downstream of the pre-reactor stage and connected via a conduit to the pre-reactor stage for separation of methanol from the first methanol-containing product stream and for separation of a residual gas stream;
• a feed conduit connected to the first separator for introducing the residual gas stream into a gas compressor;
• a feed conduit for introducing the residual gas stream compressed to reaction pressure in the gas compressor into a main reactor stage, wherein
• the main reactor stage is configured for catalytic conversion of the residual gas stream into a second methanol-containing product stream;
• a second separator arranged downstream of the main reactor stage and connected via a conduit to the main reactor stage for separation of methanol from the second methanol-containing product stream,
• wherein he pre-reactor stage is configured for conversion of an input gas having a carbon monoxide content of 25% to 36% by volume.