Enthalpies of absorption of hydrogen sulfide in aqueous methyldiethanolamine solutions

Abstract

An isothermal flow calorimeter was used to measure the enthalpies of absorption of hydrogen sulfide in aqueous 1.7, 3.0 and 4.3 M methyldiethanolamine (MDEA) solutions. The experimental temperature and pressure ranges were 299.8–399.8 K and 0.087–1.12 MPa respectively. The calorimetric data were found to be useful in determining the equilibrium concentrations of H 2S in the MDEA solutions. Both enthalpy of absorption and equilibrium concentration data for H 2S-aqueous MDEA systems are reported. The enthalpy of absorption of H 2S in aqueous MDEA solutions was found to be independent of pressure, and linearly dependent upon the temperature and concentration. An equation is given for predicting the enthalpy of absorption over the temperature, pressure, and concentration ranges investigated.