Hydrogen sulfide solubility in 50 wt% and 70 wt% aqueous methyldiethanolamine at temperatures from 283 to 393 K and total pressures from 500 to 10000 kPa

The hydrogen sulfide (H2S) absorption capacity of a 70 wt% aqueous methyldiethanolamine (MDEA) solution was investigated in a static-analytic apparatus at temperatures of 283, 353 and 393 K and pressures of 2000, 6000 and 10000 kPa in the presence of methane. New experimental data were also produced for a 50.1 wt% aqueous MDEA at 323 K and pressures of 500 and 3000 kPa as part of the apparatus validation procedure. A model based on electrolyte non-random two-liquid (eNRTL) activity coefficient model to describe the liquid phase and Peng-Robinson Equation of State to describe the vapor phase non-idealities was developed for the system H2S-MDEA-H2O, which can potentially be used also for the system in the presence of methane at low pressures. Vapor pressure measurements of pure MDEA were also performed in the range of 405–435 K in an ebulliometer and parameters for the Antoine correlation were proposed.