Abstract:In this paper, a new approach has been developed for estimating the potential of retrofitting an existing power plant to oxy-firing and determining the safe operation regime of the boiler under enriched oxy-combustion. A Computational Fluid Dynamics (CFD) technique has been employed to simulate the complex coal combustion and heat transfer to the furnace water walls and heat exchangers under air-firing and oxy-firing conditions. A set of reduced order models (ROMs) have been developed to link the CFD predictions to the efficient whole plant process models in order to simulate the performance of the power plant under different load and oxygen enrichment conditions if retrofitted to oxy-firing. The simulations of a 500MW e power plant unit indicate that it is possible to retrofit it to oxy-firing without affecting the overall performance of the unit. Similar heat transfer characteristics and steam generation can be achieved to those under air-firing, although the temperature of the boiler wall may increase after retrofitting. The upper limits for the oxygen enrichment at different power loads are identified and the feasible oxygen concentration range within 25%-27% is suggested for the oxy-coal operation of this retrofitted power plant investigated.However, the peak temperature on the superheater platen 2 may increase in the oxy-coal mode at high power load beyond 450MW e . If the tube material cannot endure the temperature increase, then an upgrade on the material is required.