(160c) Techno-Economic Analysis and Process Design of a CO2 Capture Process for a 500 MWe IGCC Power Plant

Carbon dioxide (CO₂) is the primary greenhouse gas emitted through human activities that is associated with climate change. Coal-fired power plants emit considerably more CO₂ per unit energy generated compared to other fuels; however, national and global reliance on coal for electricity generation is expected to continue to be significant in the next several decades. Integrated Gasification Combined Cycles (IGCC) processes, are expected to be among the leading contenders for power generation because of their higher efficiencies, flexible products and potential environmental advantages compared to conventional coal combustion (pulverized coal) processes. The high temperature and pressure of syngas produced in gasifiers suggests that MgO-based sorbents can be a good candidate for carbon capture processes. This study addresses the process design and economic feasibility of a Carbon Capture and Storage (CCS) process involving regenerable MgO-based sorbents for a 500 MWe IGCC power plant. A regenerative high pressure and high temperature process is presented for CO₂ capture from precombustion IGCC plants which utilizes MgO-based solid sorbents. The process consists of several circulating fluidized beds (CFB) operating at elevated temperature and pressure designed for continuous CO₂ capture.  A sorbent make-up stream enters the system to compensate the sorbent degradation and a bypass stream is used to optimize the operation of the unit. The results obtained in this study indicated that a regenerative CO₂ capture process based on MgO-based solid sorbents is capable of removing 90% of CO₂ in precombustion IGCC plants with an estimated cost below $40/ton of carbon captured. Also, it was shown that the cost of sorbent is the major operating cost of the system. Thermal and heat integration of the system demonstrated that nearly pure (about 97.5%) liquid CO₂ stream that can be produced and sequestered.