Scrubbing of CO2 greenhouse gases, accompanied by precipitation in a continuous bubble-column scrubber

A continuous bubble-column scrubber that absorbs carbon dioxide (CO(2)) gas using an alkaline solution under a pH-stat condition was used to explore the effects of the pH of the solution, gas concentration, gas-superficial velocity, and liquid-flow rate on the absorption rate and volumetric mass-transfer coefficient of CO(2). When the scrubbing factor was evaluated, this scrubber outperformed other scrubbers. Correlations of local volumetric mass-transfer coefficients with process variables are presented here and the gas-liquid interfacial area and individual mass-transfer coefficient are discussed to provide insight into the mass-transfer mechanism. Investigation of the liquid-sitle mass transfer coefficient revealed that the k(L)/[OH(-)](0.5) value was a constant, thus demonstrating that the system obeyed second-order kinetics. Evidence also shows that liquid-side resistances are within the range of 27%-99%, indicating that gas-side mass-transfer resistance, cannot be neglected in some cases. This implies that the absorption mechanism is flexible and can be shifted by adjusting the process parameters.