Post-combustion CO2-capture from coal-fired power plants: Preliminary evaluation of an integrated chemical absorption process with piperazine-promoted potassium carbonate

The simulation tool ASPEN Plus® is used to model the full CO2-capture process for chemical absorption of CO2 by piperazine-promoted potassium carbonate (K2CO3/PZ) and the subsequent CO2-compression train. Sensitivity analysis of lean loading, desorber pressure and CO2-capture rate are performed for various solvent compositions to evaluate the optimal process parameters. EbsilonProfessional® is used to model a 600 MWel (gross) hard coal-fired power plant. Numerical equations for power losses due to steam extraction for solvent regeneration are derived from simulation runs. The results of the simulation campaigns are used to find the process parameters that show the lowest specific power loss. Subsequently, absorber and desorber columns are dimensioned to evaluate investment costs for these main components of the CO2-capture process. Regeneration heat duty, net efficiency losses and column investment costs are then compared to the reference case of CO2-capture by monoethanolamine (MEA).CO2-capture by piperazine-promoted potassium carbonate with subsequent CO2-compression to 110 bar shows energetic advantages over the reference process which uses MEA. Additionally, investment costs for the main components in the CO2-capture process (absorber and desorber columns) are lower due to the enhanced reaction kinetics of the investigated K2CO3/PZ solvent which leads to smaller component sizes.