| 摘要 |
<p>PURPOSE: To separate and recover carbon dioxide at a high recovery while saving energy by returning exhaust gas from the second stage adsorption column to the inlet of the first stage adsorption column and returning the exhaust gas containing carbon dioxide at high concentration from the second stage adsorption column in a replacing purge process to the inlet of the second stage adsorption column. CONSTITUTION: Carbon dioxide adsorbed and separated in the first stage adsorption column 2a, after being desorbed at reduced pressure by a vacuum pump 7, is supplied to the second stage carbon dioxide adsorption column 3a by a surge tank 8 and a blower 9. Since the concentration of carbon dioxide in residual gas after the adsorption and separation of carbon dioxide in an adsorption process in the second stage adsorption column 3 is still higher than that in raw gas, the gas is returned to the inlet side by a blower. Since the concentration of gas discharged from the top of the adsorption column in a replacing purge process is as high as that of desorbed gas from the first stage adsorption column, the gas is returned to the inlet of the second stage adsorption column 3 through a line 12. In this way, the load of carbon dioxide in the first stage adsorption column can be reduced, and the amount of exhaust gas circulated from the second stage adsorption column to the first stage adsorption column can be reduced.</p> |
