Techno-economic assessment of waste heat recovery enhancement using multi-channel ceramic membrane in carbon capture process

Abstract

This study retrofitted the rich-split carbon capture process by introducing a commercial multi-channel ceramic membrane heat exchanger (Multi-CMHE) for waste heat recovery from the stripped gas vented from the CO2 stripper. The parametric study and economic analysis were conducted to comprehensively evaluate the feasibility, adaptability, and net profit of Multi-CMHE-modified rich-split monoethanolamine-based carbon capture process. Results showed that a large pore-sized Multi-CMHE has a low mass transfer flux but a high heat transfer flux. An increase in the bypassed CO2-rich solvent flow rate, water vapor molar fraction in the stripped gas and total gas pressure in addition to a decrease in the CO2-rich solvent temperature can greatly enhance the heat recovery performance. The maximum specific heat recovery can reach up to 1423.3 kJ/kg-CO2 for the 30 nm pore-sized Multi-CMHE. Furthermore, an economic analysis of the Multi-CMHE-modified rich-split carbon capture process was conducted based on the maximum stripped gas treatment amount at a fixed membrane area. Technical and economic feasibilities of the Multi-CMHE modification were thus confirmed. The maximum net profit reaches to USD$ 2.73/t-CO2 when the regeneration heat saving is 900 kJ/kg-CO2. Sensitivity analyses indicated that this modified process is preferred in a high fuel price scenario. Additionally, the further membrane innovation should be oriented to improve the heat recovery performance and maximize the net profit in the future.