Mass transfer of chemical absorption of CO2 in a serpentine minichannel

Based on the online method, the absorption kinetics and mass transfer of CO2 in potassium carbonate solution in a serpentine minichannel are studied. Three flow patterns are observed: slug-bubbly flow, slug flow, and slug flow with precipitation of SiO2. It is observed that the length of bubble decreases linearly with the increase of the travelling distance of bubble x in slug flow, based on which the volumetric mass transfer coefficient (kLa) is calculated. The results show that the average bubble velocity vb is only a function of the gas and liquid flow rates, and it remains unchanged in the whole flow process. Based on the online method, the instantaneous mass transfer coefficient, and instantaneous pH are studied. It's found that the instantaneous mass transfer coefficients kLa and kL increase with the mass transfer of bubbles along the flow direction in the slug flow. It is concluded that the convection in the liquid slug plays a major role in controlling the mass transfer of fast chemical absorption in a serpentine minichannel.