| 摘要 |
PURPOSE:To desorb CO2 remaining in an adsorbent when an absorbing process in finished, into raw gas and besides, to recover CO2 gas having high purity from raw gas having a small CO2 content, by setting the pressure in an adsorbing tower than the adsorbing process is finished, at the pressure higher than the partial pressure of CO2 in the raw gas supplied in the adsorbing process. CONSTITUTION:The raw gas having a relatively small CO2 content is supplied 2, 21 to the adsorbing tower 11 and continued to supply by opening valves 711, 712, after increasing the pressure in the tower 11 to a slightly higher pressure more than atmosphere pressure (pressure increasing and adsorbing process). During this period, a washing process is carried out in an absorbing tower 13, and a desorbing process in an adsorbing tower 14. The adsorbing process in the tower 11 is finished by closing the valves 711, 712 and a released gas having a higher CO2 concn. than one in the raw gas is introduced from the tower 14 to the tower 11. The CO2 in the released gas is adsorbed with the adsorbent in the tower 11 after the adsorbing process and the residual waste gas is exhausted 3. As the result, the amt. of CO2 adsorbed with the adsorbent in the tower 11 can be increased than one at the end of the absorbing process. |
