Experimental and rate‐based modeling study of CO2 capture by aqueous monoethanolamine

Reducing high energy consumption is one of the greatest challenges facing CO2 capture by aqueous monoethanolamine. The regeneration energy and its energy components (sensible heat, heat of reaction, and water vaporization heat) were evaluated experimentally in a bench‐scale regeneration system. A rate‐based model was developed in an Aspen Plus simulator to simulate the desorption process. The results predicted by the rate‐based model are in good agreement with experimental data. The operational parameters for the standard absorption/desorption process for CO2 capture are then optimized to reduce the energy consumption. The results show that for a 30 wt% MEA solution with 90% removal efficiency, the optimum operational parameters are an L/G ratio of 2.90 kg/kg, a lean loading of 0.24 mol/mol, a 5 °C temperature approach to the heat exchanger and a stripper operating pressure of 180 kPa with a 119 °C reboiler temperature. A minimum energy consumption of 3.52 GJ/tonCO2 was achieved. Under the optimal process conditions, the enthalpy of absorption is the main contribution to the total regeneration energy followed by the water vaporization heat and sensible heat.