Experimental evaluation of electrochemically mediated amine regeneration integrated with amine thermal swing for CO2 capture at optimized desorption temperatures

Abstract

In the present study, the integration of electrochemically mediated amine regeneration (EMAR) with amine thermal swing process is investigated as a novel method for CO₂ capture, utilizing experimental practical data. The aim is to increase the absorption-desorption temperature difference in order to improve the energy efficiency of the capture process and hamper the amine degradation issue at high desorption temperatures. A comprehensive experimental procedure is presented, and an experimental process setup is designed and constructed. As the main novelty of the study a special heating-cooling subsystem is incorporated with the base EMAR process in order to devise a combined electrochemical-thermal system. The performance of the system is evaluated at sequential incremental desorption temperatures while the absorption temperature is kept constant. Relevant data, including the desorbed CO₂ flow, absorbed CO₂ flow, stream points temperature, and cell voltage are collected. Based on the data collected, two performance parameters are calculated, including normalized carbon separation work, and CO₂ desorption density. Based on these performance parameters the system's capability is assessed, and the optimal desorption temperature is ultimately selected. The presented electrochemical-thermal CO₂ separation system, operating with a chloride salt system, demonstrates its best energetics performance at a desorption temperature of 44 °C, resulting in a normalized capture work of 95.2 kJ/molCO₂. Under these optimal conditions, the cell's average voltage is measured to be 0.37 V, and the CO₂ desorption density is determined to be 0.71 l.min⁻¹.m⁻².