Post-combustion CO 2-capture from coal-fired power plants: Preliminary evaluation of an integrated chemical absorption process with piperazine-promoted potassium carbonate

Abstract

The simulation tool ASPEN Plus ® is used to model the full CO 2-capture process for chemical absorption of CO 2 by piperazine-promoted potassium carbonate (K 2CO 3/PZ) and the subsequent CO 2-compression train. Sensitivity analysis of lean loading, desorber pressure and CO 2-capture rate are performed for various solvent compositions to evaluate the optimal process parameters. EbsilonProfessional ® is used to model a 600 MW el (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 CO 2-capture process. Regeneration heat duty, net efficiency losses and column investment costs are then compared to the reference case of CO 2-capture by monoethanolamine (MEA). CO 2-capture by piperazine-promoted potassium carbonate with subsequent CO 2-compression to 110 bar shows energetic advantages over the reference process which uses MEA. Additionally, investment costs for the main components in the CO 2-capture process (absorber and desorber columns) are lower due to the enhanced reaction kinetics of the investigated K 2CO 3/PZ solvent which leads to smaller component sizes.