METHOD FOR PROCESSING FISCHER-TROPSCH OFF-GAS

摘要

This invention concerns a method for producing a gas comprising at least 80 vol.% carbon monoxide from a Fischer-Tropsch off-gas. The method comprises the following steps: (1) feeding Fischer-Tropsch off-gas through a column comprising an adsorbent bed at high pressure and discharging effluent; (2) reducing the pressure in the column and the bed slightly; (3) rinsing the column and the adsorbent bed with methane or carbon dioxide; (4) rinsing the column and the adsorbent bed with carbon dioxide; (5) reducing the pressure of the column and adsorbent bed to a low pressure; (6) rinsing the column and adsorbent bed with a mixture of hydrogen and nitrogen; (7) pressurizing the column and adsorbent bed to a high pressure again using a mixture of hydrogen and nitrogen. The carbon monoxide rich product stream obtained in step (3) can be sent as feed to a Fischer-Tropsch reaction. Step (4) produces a methane stream comprising at least 80 vol.% methane. In a preferred embodiment a gas comprising at least 80 vol.% hydrogen is produced as well.