Performance Simulation and Cost Assessment of Oxy-Combustion Process for CO2 Capture from Coal-Fired Power Plants

In order to mitigate green house gas emissions, CO2 from large sources such as coal-fired power plants should be economically captured and sequestered. This paper describes the performance modeling and cost assessment of processes designed to capture and compress CO2 from sub-critical pulverized coal fired power plants (PC) and Integrated Gasification Combined Cycle (IGCC) units. Plant capacity of 533 MWe gross power output firing western PRB coal was considered. Oxy-Combustion (PC-OC) and amine scrubbing technologies (PCMEA) are considered as technology options to capture CO2 from PC plants and Selexol process (IGCC-S) to capture CO2 from IGCC plant. Detailed results of the mass and energy balance were obtained from steady state simulations. Cost models were developed to estimate the capital, operating, electricity and the CO2 avoidance costs for each technology. The process simulations showed that, with sub-critical steam cycle, the PC-OC and PC-MEA processes with CO2 compression to 80 bars (1160 psi) decreases the net power output available by 28% and 30% respectively compared to PC plant with no capture. The economic analysis showed that the cost of electricity for the PC-OC plant increased by about 60%, PCMEA plant by 79% and IGCC-S plant by 43%, compared to the PC plant without CO2 capture. The CO2 avoidance cost for a new sub-critical PC-OC plant was $36/tonne, compared to $52/tonne for PC-MEA plant and $26/tonne for IGCC-S plant. For new or retrofit PC plant applications, PC-OC is more economical than PC-MEA. IGCC with Selexol is economically favorable for new coal power plants compared to a sub-critical PC plant. Economics of the PC-OC process can be further improved by considering (ultra) supercritical power plants. The detailed performance and economics results are presented in the paper along with pilot scale experimental results of the PC-OC process.