Methanol process

Abstract

A process is described for the synthesis of methanol comprising the steps of: (i) passing a first synthesis gas mixture comprising a make-up gas and a first loop recycle gas stream through a first synthesis reactor containing a cooled methanol synthesis catalyst to form a first product gas stream, (ii) recovering methanol from the first product gas stream thereby forming a first methanol-depleted gas mixture, (iii) combining the first methanol-depleted gas mixture with a second loop recycle gas stream to form a second synthesis gas mixture, (iv) passing the second synthesis gas mixture through a second synthesis reactor containing a cooled methanol synthesis catalyst to form a second product gas stream, (v) recovering methanol from the second product gas stream thereby forming a second methanol-depleted gas mixture, and (vi) forming the first and second loop recycle gas streams from the second methanol-depleted gas mixture, wherein the first synthesis reactor has a higher heat transfer per cubic metre of catalyst than the second synthesis reactor and the recycle ratio of the first loop recycle gas stream to form the first synthesis gas mixture is in the range 0.1 to 1:1, and the recycle ratio of the second loop recycle gas stream to form the second synthesis gas mixture is in the range 1.1:1 to 6:1.