Studies on effect of water on the absorption of CO2 in AMP/DMSO solution using a reaction calorimeter

The humidity in industrial flue gases and the hygroscopicity of DMSO induce the accumulation of water in precipitating non-aqueous AMP/DMSO solutions. In this work, the effects of water on the solubility of CO 2 and the heat of absorption in an AMP/DMSO solution were determined using a true heat flow reaction calorimeter. Experiments were performed at 30 °C and 80 °C with 25%AMP in 75%DMSO solutions containing 15 wt%, 20 wt%, and 25 wt% water. The cyclic capacity was similar for the solution with 15 wt% water and a non-aqueous AMP/DMSO solution but slightly decreased with increase in water content. The absorption of CO 2 increased with increasing water content under rich (30 °C) and lean (80 °C) loading conditions, due to the additional formation of bicarbonates and carbonates. The differential heat of absorption decreased with increases in water content. Precipitation was observed for the water contents studied up to 25 wt%, suggesting that a water content up to 25% is acceptable in the system. On examination of the crystal structure by light microscopy, the precipitate that formed is likely to be AMP carbonate for all water contents which is further confirmed by solid state 13C NMR spectroscopic analysis.