Modification of postcombustion CO₂ capture process: A techno-economic analysis

Postcombustion CO₂ separation using aqueous amine solution has a great potential to minimize CO₂ emissions but is expensive due to huge energy requirement for solvent regeneration. Several structural modifications can be implemented to minimize the regeneration energy requirement and optimize the energy efficiency. In this study, we evaluated the techno-economic benefits of three stripping modifications, namely lean vapor compression (LVC), stripper overhead exchanger (SOE), and an advanced hybrid configuration (LVCSOE) in a single flowsheet aimed at reducing the energy consumption of CO₂ separation process using 30 wt.% monoethanolamine (MEA) solution. All the configurations were simulated using Aspen Plus^® rate-based modeling, while capital investment was evaluated using Aspen Economic Analyzer^®. All the modifications reduced the energy consumption and showed economic benefit compared to the base case. The optimal configuration was LVCSOE, which reduced the energy requirement for solvent regeneration and the CO₂ capture cost by 18% and 5.3%, respectively, and can save 5.4 million USD annually. Additionally, sensitivity analysis of economic variables suggested that CO₂ capture cost is more sensitive to regeneration steam cost than any other economic parameter. Furthermore, the effect of regeneration steam cost revealed that the implementation of an advanced process configuration can result in higher net savings as compared to the base case at high fuel price.