Mass transfer with complex chemical reactions. Simultaneous absorption of H2S and CO2 in solutions of alkanolamines

An absorption model has been developed which is able to calculate the simultaneous absorption rates (and corresponding enhancement factors) of two gaseous components into a reactive liquid. In the liquid phase multiple complex parallel reversible reactions may take place. This model, for example, can be used for design and development of gas-treating processes for the selective removal of hydrogen sulphide. Due to the implementation of an additional transformation of the spatial coordinate, the required computational time could be reduced substantially without loss of accuracy. The present model can be incorporated into an overall absorption module for column design and simulation. Experimentally determined simultaneous absorption rates of H2S and CO2 in aqueous solutions of alkanolamines and mixtures of alkanolamines can be predicted satisfactorily well for the conditions where both gases have a mutual interaction on the respective rates. The experiments were carried out in a stirred vessel with a flat surface over a wide range of process conditions.