Modelling and optimization of coal-fired power plant generation systems with CO2 capture

This thesis investigates the capture of CO2 from the flue gas of coal-fired power plants using an aqueous solution of MEA, and the main aim of this thesis is the development of an optimized amine-based post-combustion CO2 capture (PCC) process that can be integrated optimally with a pulverized coal-fired power plant. The relevance of this thesis cannot be overemphasised because the reduction of solvent regeneration energy is the focus of most of the solvent-based post-combustion CO2 capture (PCC) research currently being performed globally. From the view point of current research and development (R&D) activities worldwide, three main areas are being investigated in order to reduce the regeneration energy requirement of an amine-based PCC process, namely: (i) development of new solvents with better overall performance than 30 wt% monoethanolamine (MEA) aqueous solution, (ii) PCC plant optimization, and (iii) optimal integration of the PCC Plant, including the associated CO2 compression system, to the upstream power plant. In this thesis, PCC plant optimization and the optimal integration of an optimized PCC Plant, including the associated CO2 compression system, with an upstream coal-fired power plant has been investigated. Thus, an integrated process comprising ~550 MWe (net power after CO2 capture and compression) pulverized coal-fired (PC-fired) supercritical power plant, an MEA-based post-combustion capture (PCC) plant and a CO2 compression system has been modelled, simulated and optimized. The scale-up design of the PCC plant was performed using a novel method based on a rate-based calculation and thus the unnecessary over-design of the PCC plant columns was avoided. Furthermore, because of the importance of the operating pressure of the stripper in a PCC plant integrated to a PC-fired power plant, the impact of the operating pressure of the stripper on the net plant efficiency of the integrated system has been quantified. Also, the impacts of coal type on the overall performance of the integrated process have been quantified.