Process of producing methanol

A process of producing methanol from a synthesis gas containing hydrogen and carbon oxides by reactions in the presence of copper-containing catalysts under pressures in the range from 20 to 120 bars and at temperatures in the range from 200.degree. to 350.degree. C.,

• wherein the synthesis gas is fed into a first synthesis reactor at an inlet temperature in the range from 220.degree. to 270.degree. C., said synthesis gas mainly comprising hydrogen and containing 0 to 15% by volume carbon monoxide and 15 to 25% by volume carbon dioxide, the stoichiometric number S=(H.sub.2 -CO.sub.2):(CO+CO.sub.2) of said synthesis gas being at least 1.9 and the volume ratio CO.sub.2 :CO of said synthesis gas being at least 2:1,
• said first synthesis reactor being a single shaft reactor containing a fixed bed of a copper-containing catalyst, reaction in said shaft reactor being carried out adiabatically and without a recycling of synthesis gas, furthermore, there being no indirect cooling of said fixed bed of catalyst and no synthesis gas being fed into said fixed bed for cooling purposes,
• from the first synthesis reactor withdrawing a first product mixture containing methanol vapor, cooling said first product mixture and condensing methanol, separating condensed methanol from the gaseous components of the first product mixture and feeding the gaseous components to an inlet of a second synthesis reactor,
• said second synthesis reactor containing tubes which are indirectly cooled by boiling water, said tubes containing a copper-containing catalyst and said gaseous components are passed through said tubes, a second product mixture containing methanol vapor is withdrawn from an outlet of said second synthesis reactor, said second product mixture being cooled to condense methanol, separating condensed methanol from the gaseous components of the second product mixture and feeding at least part of the gaseous components of the first and second product mixtures to the inlet of said second synthesis reactor.