Gas phase mass transfer in falling film microreactors (FFMRs) with the absorption of CO2 into aqueous solutions of NaOH was investigated.The overall gas-phase mass transfer coefficient increases with NaOH concentration,but decreases as the concentration of CO2 increases.There exists an entrance effect,hindering the mass transfer,which is caused by the dead volume for gas-phase flow in the gas chamber in FFMRs.The entrance effect has a larger impact in a shorter FFMR owing to the relatively large dead volume with respect to that of gas chamber.A decrease in the depth of gas chamber facilitates the mass transfer process.Therefore,the gas-phase entrance or geometry of the gas chamber should be designed appropriately to reduce the entrance effect and improve the mass transfer.
