Energy, Vol.168, 380-392, 2019
Thermodynamic considerations on MEA absorption: Whether thermodynamic cycle could be used as a tool for energy efficiency analysis
Regeneration heat duty is not the only metric for an absorbent, but it is one of the most decisive factors that define the performance of chemical absorption carbon capture technologies. Nevertheless, from the thermodynamic point of view, there are still insufficient studies on evaluating and analyzing the energy efficiency performance of liquid-phase chemisorption technologies, especially considering the entire process. This study puts forward a systematic method for energy-efficient analysis of liquid-phase chemisorption technologies based on thermodynamic cycle analysis. A 4-Step monoethanolamine (MEA) based liquid-phase chemisorption cycle is established and expressed on the equilibrium isothermals diagram of MEA-CO2-H2O mixture. Then the influences of cyclic parameters on the energy efficient performance of the entire process or system are evaluated taking the minimum separation work, the absolute energy consumption, and the second law efficiency as performance indicators. Results show that for a typical 4-step cycle at baseline condition which approaches to an ideal operation status, the second law efficiency is in the range of 22.81%-32.99% between 373 K and 393 K. (C) 2018 Elsevier Ltd. All rights reserved.