Evaluation of the potential of retrofitting a coal power plant to oxy-firing using CFD and process co-simulation

A new approach has been developed in order to estimate the potential of retrofitting an existing power plant to oxy-firing and the safe operation regime of the retrofitted boiler under oxy-combustion condition has been determined. Computational Fluid Dynamics (CFD) techniques have been employed to simulate the 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 (ROM) has been developed to link the CFD predictions to the whole plant process model in order to simulate the performance of the power plant under different load and oxygen enrichment conditions in an efficient manner. Simulation results of a 500° MWe power plant unit indicate that it is possible to retrofit it to oxy-firing without affecting its overall performance. Further, the feasible range of oxygen enrichment for different power loads is identified to be between 25% and 27%. However, the peak temperature on the superheater platen 2 may increase in the oxy-coal mode at a high power load beyond 450° MWe.