The Effect of CO₂ Loading on the Solubility of Ethane and Propane in Aqueous Alkanolamine Solutions

Solubility of ethane and propane in aqueous solutions of N-methyldiethanolamine (MDEA, 25 and 50 wt %), 2-(2-aminoetoxy)ethanol or diglycolamine (DGA, 35 and 52.5 wt %), diethanolamine (DEA, 35 wt %), ethanolamine (MEA, 14.6 wt %), and a mixture of MDEA and piperazine (42.1 wt % MDEA +8 wt % Pz) was measured at temperatures of 298, 333, 353, and 373 K and system pressures of 0.8 MPa for propane and 1.6 MPa for ethane. The effect of CO₂ loading on the solubility of ethane and propane was measured at 333 K for five of the solutions. It is shown that solubility is increased with increasing amine concentration (salting-in effect) and decreased with increasing CO₂ loading (salting-out effect). The salting-in and salting-out ratios are calculated using Henry’s law constants. The results are compared with predictions from the ProMax simulation tool.