Patent attributes
The invention relates to a process and a plant for producing methanol from an input gas including carbon monoxide and hydrogen using a pre-reactor stage and a main reactor stage. Input gas produced at and under elevated pressure is initially introduced into a pre-reactor stage for catalytic conversion into a first methanol-containing product stream. After separation of methanol from the first methanol-containing product stream and discharging from the pre-reactor stage a remaining gas stream is introduced into a main reactor stage as a residual gas stream after compression to reaction pressure for catalytic conversion into a second methanol-containing product stream, After separation from the second methanol-containing product stream methanol is discharged from the main reactor stage. Using an input gas having a carbon monoxide content of 25% to 36% by volume results in large savings in respect of the compressor output required for the production process.