Kinetic Study of Carbonyl Sulfide (COS) Absorption by Methyldiethanolamine Aqueous Solutions from 415 mol/m3 to 4250 mol/m3 and 313 K to 353 K

Abstract

In this work, we present the rigorous modeling of carbonyl sulfide (COS) absorption by N-methyldiethanolamine (MDEA) aqueous solutions, taking into account the experimental data of our previous works, for an extended temperature range of 313−353 K and an amine concentration range of 415−4250 mol/m3. We intend to clarify the discrepancies on the kinetic data and the validation of new kinetic data for the extended temperature range. The modeling of COS absorption data is based on the COS mass transfer and chemical reaction at the liquid/gas interface, considering Henry's law and the zwitterion mechanism. Reaction rate constants were estimated using a Downhill simplex optimization procedure. The enhancement factor was estimated as a function of temperature and amine concentration. The water dissociation rate was assumed to be negligible. In this work, the determined values for the reaction rate constants allow a satisfactory concordance between experimental and modeled data for the entire temperature range and validate the few data reported previously for low temperatures.