Methyl Mercaptan Absorption Study into a Hybrid Solvent Mixture Composed of Diethanolamine/Methanol/Water at Temperatures from 313.9 to 353.0 K

Abstract : Methyl mercaptan (CH3SH) absorption kinetics was studied for a hybrid solvent mixture consisting of diethanolamine/water/methanol for concentrations of 40/40/20 wt % and 40/20/40 wt % and for temperatures between 313.9 and 353.0 K. CH3SH is usually found in sour gases and is removed along with other acid gases. Physicochemical characterization is performed for the treatment of CH3SH with the hybrid solvent which is to date lacking chemical absorption data. A systematic methodology is proposed to assess the effect of each mass transfer, thermophysical properties, and the chemical reactions in the system. An empirical novel equation is proposed for the Henry’s law constant solubility of CH3SH with respect to the methanol in solution. A chemical kinetic mechanism based on the formation of a zwitterion complex is proposed for the chemical species in the liquid phase. Results validated with experimental data enabled all the reaction constants to be parametrized in terms of the Arrhenius law.