Dynamic modelling and analysis of supercritical coal-fired power plant integrated with post-combustion CO2 capture

Abstract

Despite the advances in power plant and CO2 capture modelling, only a few studies have presented a dynamic process model and analysis of the post-combustion CO2 capture integrated with a dynamic model of supercritical power plant. This study presents a dynamic model of a supercritical coal-fired power plant (SCPP) integrated with a dynamic model of MEA-based post-combustion CO2 capture plant (PCC). This study focuses on the impact of integrating PCC unit on the load following the mode of operation of the SCPP. The dynamic model of the PCC was validated against a pilot plant data and was scaled-up to capture the flue gas flow from 600-MWe SCPP. The SCPP model was validated with actual plant operational data for steady-state conditions at full load and at transient load ramp. The dynamic response of the integrated SCPP-PCC model due to changes in load demand is presented. The response of the following variables to changes in load level investigated includes the following scenarios: (i) the flue gas flow rates, (ii) the pulverized coal flow, (iii) the net efficiency of the SCPP, and (iv) and the CO2 capture level. The simulation shows that the CO2 capture level is very sensitive to the solvent-flue gas (L/G) ratio. In addition, steam reduction/stripper stop was analysed as a strategy for operating the SCPP integrated with PCC unit under the UK grid requirement as regards primary frequency response. The result shows that the stripper stop mechanism produces about 4.67 % MCR (~28 MWe) increase in the SCPP at full-load condition. This is however, not sufficient for the 10 % MCR required for the primary response (usually within 10-30 s).