Sub-ambient membrane process for CO2 removal in the industrial sector: Iron and steel, cement, and refinery

With the growing interest in net-zero emissions worldwide, the focus on CO2 capture technologies has changed from fossil fuel-combusted power plants to industries such as steel and iron, cement, and oil refining. In this study, a sub-ambient membrane process is applied to representative industrial fields that emit large amounts of CO2 into the atmosphere. In particular, a low-temperature operation for the membrane module is used to improve CO2/N2 selectivity. Additionally, the methodology of heat integration with the propane refrigeration system and the residual refrigeration energy from the retentate of the membrane and the top side of the CO2 liquefaction column is utilized to minimize the refrigeration energy. The genetic algorithm is incorporated to optimize equipment size and operating conditions, subject to capital and operating cost parameters. The CO2 capture cost is observed to have reduced with increasing CO2 concentration in the feed stream. Furthermore, a sensitivity analysis is conducted to examine the effect of the change in the CO2 capture cost at different CO2 capture rates with various carbon tax costs.