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 a mixture of methane and carbon dioxide; (4) reducing the pressure of the column and adsorbent bed to a low pressure; (5) rinsing the column and adsorbent bed with a mixture of hydrogen and nitrogen; (6) pressurizing the column and adsorbent bed to a high pressure again using a mixture of hydrogen and nitrogen. The product stream obtained in step (3) which comprises at least 80 vol% carbon monoxide can be sent as feed to a Fischer-Tropsch reaction.In a preferred embodiment a gas comprising at least 80 vol% hydrogen is produced as well.