Process and plant for producing methanol from synthesis gases having a high proportion of carbon dioxide

A process for producing methanol, comprising:

• a) providing an input gas comprising carbon oxides and hydrogen, wherein the proportion of carbon dioxide in the input gas, based on the total amount of the carbon oxides, is at least 80% by volume;
• b) introducing the input gas as a first fresh gas stream into a first compressor stage for precompression of the first fresh gas stream to obtain a second fresh gas stream;
• c) introducing a recycle gas stream and the second fresh gas stream into a second compressor stage for compression of the recycle gas stream and the second fresh gas stream to synthesis pressure to obtain a synthesis gas stream;
• d) catalytically converting the synthesis gas of the synthesis gas stream in a plurality of serially arranged reactor stages at synthesis pressure to obtain a product stream comprising methanol and unreacted synthesis gas per reactor stage;
• e) cooling the product stream obtained per reactor stage for condensation and separation of methanol from unreacted synthesis gas and introducing unreacted synthesis gas into a respective subsequent stage of the serially arranged reactor stages;
• f) withdrawing unreacted synthesis gas from at least one of the reactor stages as a recycle gas stream for introduction of the recycle gas stream into the second compressor stage according to step c).