Holistic Approach to Understanding and Managing Amine Degradation during Post-combustion CO <sub>2</sub> Capture Operation

Abstract

Since most of real-world operations of post combustion capture of CO2 are burdened with issues on oxidative and thermal degradation of amine solutions, it is advantageous to find operational means to maintain process performance even while solution degradation proceeds. Although the chemical composition of degraded amine solutions is complex and variable, the relationship between solution properties, operating conditions, and process performance is reasonably explainable. As a strategy to deal with a plethora of amine compounds and degradation products, we propose a holistic approach which connects amine degradation to process performance via the alteration of solution properties. This approach includes altering the operating condition in response to the change in solution properties caused by amine degradation. This study is based on the comparison with fresh monoethanolamine aqueous solution and its degraded solution produced by continuous operation of a 10 kg-CO2/day bench-scale CO2 capture system. The solution properties and process performance were obtained experimentally as degradation progressed. From the analysis of obtained data, it was elucidated that the decrease in the CO2 loading capacity due to the amine degradation lead to deterioration of process performance. Moreover, it was indicated that the appropriate liquid flow rate for the degraded solution tends to be higher than that for the fresh solution because of decrease in the CO2 loading capacity.