Highly efficient process for the catalytic methanation of gas mixtures containing carbon dioxide and hydrogen

摘要

A method is provided for the catalytic methanation of a gas mixture containing carbon dioxide and hydrogen, which gas mixture has a carbon monoxide content of less than 0.1%, in a reactor system (1) comprising at least two reactor stages (9, 10) arranged one behind the other, each of the two reactor stages (9, 10) contains a catalyst. The method has the following steps: (a) introducing the gas mixture containing carbon dioxide and hydrogen, which has a carbon monoxide content of less than 0.1%, into the first (9) of the two reactor stages (9, 10) arranged one behind the other; (b) catalytic methanation of the gas mixture at temperatures in the range from 300 ° C. to 600 ° C. in the first reactor stage (9); (c) partial removal of the water contained in the gas mixture emerging from the first reactor stage (9) by cooling to a temperature between 80 ° C. and 160 ° C. below the dew point and removing the water that condenses during cooling from the reactor system (1) a condensate drain (17) arranged between the first (9) and the second reactor stage (10); (d) introducing the gas mixture from which the water was partially removed in step (c) into the second reactor stage (10); and (e) post-methanization of the gas mixture at temperatures in the range from 250 ° C. to 300 ° C. in the second reactor stage (10).