Boundary-value problems in reactive gas absorption

Presented here are generalized mathematical formulations and closed-form approximate solutions for two non-linear boundary-value problems in reactive gas absorption. In the first part, we analyze by means of numerical and approximate solutions the problem of gas absorption, through a spherical gas-liquid interface, accompanied by second-order chemical reaction in the liquid phase. It is shown that bubble sphericity could enhance appreciably gas absorption due to chemical reaction, depending on the magnitude of system parameters. It is also shown that the spherical effect is unlikely to be significant in industrial gas-liquid reactors. In the second part, we address the problem of gas absorption, through a plane interface, accompanied by a second-order reaction with a volatile liquid reactant. An analytic approximate solution is developed which is applicable in all reaction regimes. The solution is accurate, simpler, and numerically more stable than other solutions reported in the literature.