Regeneration of CO2 from CO2-rich alkanolamines solution by using reduced thickness and vacuum technology: Regeneration feasibility and characteristic of thin-layer solvent

The novel regeneration concept by using reduced thickness and vacuum technology was put forward in this paper to solve the higher regeneration energy consumption in the chemical absorption process for CO2 separation from flue gas. A 120-mm I.D. vessel was precisely designed to regenerate the CO2-rich solution, and the change of the thickness of thin-layer solutions was simulated by controlling the volume of rich solution added into the vessel. The experimental results show that vacuum regeneration may be viable if the CO2-rich solution can be easily partitioned into the continuous single thin-layer solutions with an appropriate thickness. The great decrease of thin-layer solution thickness and regeneration pressure, and the increase of liquid temperature can improve the regeneration performance considerably. In addition, it is worthy to determine the optimum initial CO2 loading of rich solution, regeneration time and absorbent concentration due to the contradiction between the CO2 loading of lean solution and regeneration energy consumption per kg of CO2. Finally, the simple comparison between vacuum and heating regeneration methods shows that the novel regeneration method may have the potential to reduce the regeneration energy requirement.