Method for production of CO, H2 and methanol-synthesis gas from a synthesis gas, in particular from acetylene off-gas

A method for production of a methanol-synthesis gas product stream (2), an H2 product stream (3) and a CO product stream (4) from an H2- and CO-containing synthesis gas stream (5), said method comprising:

• portioning said H2- and CO-containing synthesis gas stream (5) into a first and a second synthesis gas substream (51, 52), and converting (100) only CO contained in said first synthesis gas substream (51) to CO2 and H2 by using steam admixed to said first synthesis gas substream (51),
• scrubbing (102) the converted first synthesis gas substream (51) and a first part (52a) of said second synthesis gas substream (52), each in a separate column, with an amine-containing scrubbing medium to scrub out CO2, wherein said amine-containing scrubbing medium is regenerated in a shared column,
• forming said methanol-synthesis gas product stream (2) from a first part (51a) of the scrubbed converted first synthesis gas substream (51) and/or a second part (52b) of said second synthesis gas stream (52), in such a manner that a ratio of (H2-CO2)/(CO+CO2) that is required for the methanol synthesis is established in the methanol-synthesis gas product stream (2), wherein said ratio is in the range from 2.0 to 2.1, wherein
• the scrubbed first part (52a) of said second synthesis gas substream (52) is further treated in a temperature-swing adsorption unit (104) and a cryogenic gas separator (109) to produce a CO product stream (4) and a crude hydrogen stream (6), and
• a second part (51b) of said scrubbed converted first synthesis gas substream (51) and said crude hydrogen stream (6) are further treated in a pressure sing adsorber to produce said H2 product stream (3).