Numerical simulation of theories for gas absorption with chemical reaction

Abstract

Abstract Steady‐ and unsteady‐state theories for interfacial mass transfer are used to model gas absorption with second‐order, reversible reaction and the absorption of CO 2 into aqueous MDEA (methyldiethanolamine). The latter case represents a system of industrial interest, having both finite rate and equilibrium reactions. Steady‐state theories studied are film theory, simplified eddy diffusivity theory, and an approximation to surface renewal theory. Higbie's penetration and Danckwert's surface renewal theories are the unsteady‐state theories reviewed. The Nernst‐Planck equations for diffusion and reaction in ionic systems are solved numerically using orthogonal collocation on finite elements. Comparisons are made between the absorption enhancement factor obtained for all theories. The applicability of approximate methods of solution for absorption with chemical reaction is also discussed.