Equation-Oriented Optimization Applied to the Optimal Design of Carbon Capture Plants Using Rigorous Models

Post-combustion capture has the potential to mitigate climate change through the reduction of CO2 emissions in the short term. Chemical absorption-based processes are the most mature technology, but process costs should be reduced to facilitate their worldwide application. In this context, we address the optimal design of absorption-based carbon capture technologies using the Aspen Plus platform in the equation-oriented (EO) mode. We show the efficiency of this tool by solving optimal design problems for three case studies: (i) conventional process using monoethanolamine; (ii) conventional process using 2-methylpiperazine; and (iii) advanced flash stripping (AFS) configuration using piperazine (PZ). The objective function is the carbon dioxide avoided cost, and we consider a flue gas with a CO2 concentration of 7.5% (molar basis). Numerical results indicate that the AFS configuration with PZ has the best energy efficiency (2.46 GJ/t-CO2) and achieves the lowest CO2 avoided cost, with a value of 98.8 $/tonne-CO2.