Aqueous solutions of potassium carbonate, with and without an amine additive, were used as the acid gas removal solvent in the Coal Gasification/Gas Cleaning Test Facility at North Carolina State University. The acid gas removal system consisted of a packed absorption column, one or more flash tanks for intermediate pressure reduction, and a packed stripping column operated with a reboiler. The removal of COb2s, Hb2sS, COS, and other species from the crude coal gas was studied, and data on the distribution of these gases in regeneration exit streams were obtained. Operating conditions for the selective removal of sulfur species were also examined. A system model for chemical solvents was developed and incorporated into a simulation program. The model was based on the mass transfer rate of a key component, COb2s, with the assumption that non-key reactive components affect the equilibrium of the key component, but not its mass transfer rate. The absorption and stripping of non-key components were assumed to be controlled by equilibrium between the gas and liquid phases in these columns. An isothermal flash model for chemical solvents was also developed and included in the program. The agreement between program predictions and pilot plant data was quite good, supporting the validity of the model. Program simulations are shown to provide insights into the effects of changes in process variables on system operations.