Gas-liquid Mass Transfer with Parallel Reversible Reactions-i. Absorption of Co, into Solutions of Sterically Hindered Amines

A numerical method developed by Versteeg et al. (1989, Chem. Engng Sci. 44,2295-2310; 1990, Chem. Engng Sci. 45, in press) is applied to some specific problems in gas-liquid mass transfer. The experimental results of Chakraborty et al. (1986, C/tern. Engng Sci. 41.997-1003) and Zioudas and Dadach (1986, Chem. Engng Sci. 41,405408) on the absorption of CO, into aqueous solutions of sterically hindered amines are evaluated with the numerical model. It is shown that studying the ahsorption nf CO, into aqueous solutions of sterically hindered amines requires a rigorous numerical solution of the differential equations describing the mass transfer instead of analytical and numerical approximations based on a reduction of the number of reactions by neglecting or lumping reactions. It is demonstrated that the absorption rates of CO, into sterically hindered amine solutions can be explained in terms of the established reactions of CO, in amine solutions alone, and no new reaction paths are necessary to explain the observed behaviour. -