Techno-economic assessment of post-combustion CO2 capture using aqueous piperazine at different flue gas compositions and flowrates via a general optimization methodology

An overall techno-economic assessment of a post-combustion CO2 capture process using aqueous piperazine is presented. A two-step techno-economic optimization approach is developed and implemented. First, two-objective technical optimization problems are solved at different combinations of CO2 capture efficiencies and CO2 concentrations in the flue gas, which aim at minimizing the specific equivalent work while maximizing the volume-based productivity of the capture process. Increasing minimum specific reboiler duties between 2.4 and 2.9 MJ(th) kg(CO2captured)(-1) are obtained for decreasing flue gas CO2 concentrations between 33 and 4 vol%, on a dry basis, with absorber packing heights below 10 m. Then, costs are computed at the technical optimal conditions as a function of the CO2 capture efficiency, flue gas flowrate and CO2 concentration. As a result, maps of minimum cost of CO2 captured, of minimum cost of CO2 avoided, and of minimum cost of CO2 generated by the CO2 point source are obtained, as well as of the associated optimal operating conditions and performance indicators of the capture process, which allow to assess the economic feasibility and performance of the capture process under different cost scenarios and assumptions when applied to different flue gas compositions and flowrates typical of industrial CO2 intensive point sources.

Automated summary

This study presents an overall techno-economic assessment of a post-combustion CO2 capture process using aqueous piperazine. A two-step techno-economic optimization approach is developed to minimize work and maximize productivity. The results show that the specific reboiler duties increase as the flue gas CO2 concentrations decrease, while the costs are computed at the technical optimal conditions as a function of CO2 capture efficiency, flue gas flowrate, and CO2 concentration. Maps of minimum cost and associated optimal conditions are obtained to evaluate the economic feasibility and performance of the capture process under different cost scenarios and assumptions.