Mass-Transfer Characteristics of the CO2 Absorption Process in a Rotating Packed Bed

This article presents systematic investigations on the mass-transfer characteristics, including the overall gas-phase volumetric mass-transfer coefficient (K(G)a) and the height of mass-transfer unit (HTU), of the CO2 absorption process into a mixture of diethylenetriamine (DETA) and piperazine (PZ) solution in a rotating packed bed (RPB). The effects of operating conditions, including PZ concentration, rotation speed, liquid volumetric flow rate, gas volumetric flow rate, gas treatment capacity of packing, inlet CO2 mole fraction, temperature, CO2 loading of lean solution, and distributor specification on K(G)a and HTU in the RPB, were systematically studied. Also, a comparison of CO2 absorption performance between the packed column with Dixon rings packing and the RPB is presented. Results indicate that both K(G)a and HTU were significantly affected by rotation speed, liquid volumetric flow rate, gas volumetric flow rate, temperature, and lean CO2 loading while the PZ concentration, inlet CO2 mole fraction, and liquid distributor had minimal effect on K(G)a and HTU. It was noted that a RPB exhibits better mass-transfer performance compared to a packed column with Dixon rings packing.