Postcombustion CO2 Capture: A Comparative Techno-Economic Assessment of Three Technologies Using a Solvent, an Adsorbent, and a Membrane

This work comparesthree postcombustion CO2 captureprocesses based on mature technologies for CO2 separation,namely, (i) absorption using an aqueous piperazine solution, (ii)adsorption using Zeolite 13X in conventional fixed beds (either vacuumswing adsorption or temperature swing adsorption), and (iii) multistagemembrane separation using a polymeric material (with CO2/N-2 selectivity of 50 and permeability for CO2 of 1700 GPU). All three capture plants are assumed to be retrofittedto a generic industrial CO2-emitting source with 12% CO2 v/v (with 95% relative humidity at the inlet temperatureand pressure of 30 & DEG;C and 1.3 bar, respectively) to deliver CO2 at 96% purity. In the cases of adsorption and membranes,the flue gas is dried before feeding it to the CO2 captureunit. In a first step, the capture processes (i.e., components anddesign parameters) are optimized based on their technical performance,defined through process exergy requirement and plant productivity;exergy-productivity Pareto fronts are computed for varyingCO(2) recovery rates. Second, the economic performance ofthe processes is assessed through a cost analysis. Estimates of CO2 capture costs are provided for each process as a functionof the plant size and CO2 recovery rate. The comparativeassessment shows that, although the adsorption- and membrane-basedprocesses analyzed may become cost competitive at the small scale(i.e., below sizes of 100 tons of flue gas processed per day) andlow recovery rates (i.e., below ca. 40%), the absorption-based processconsidered is the most cost-effective option at most plant sizes andrecovery rates.

Automated summary

This study compares three postcombustion CO2 capture processes based on mature technologies, finding that absorption-based process is the most cost-effective option, especially at most plant sizes and recovery rates.