Dynamic Simulation of a Conceptual 600MWe Oxy-fuel Combustion power plant

Oxy-fuel combustion is one of the energy utilization technologies for CO2 capture which is ready for commercial demonstration. System steady-state simulation is an effective tool to help us understand the thermodynamic properties and adjust operation conditions of oxy-fuel combustion system. Moreover, dynamic simulation is essential for understanding the dynamic characteristics of the system, which will help to design/improve control system, to develop operation strategies and to construct safety system, etc. This paper presents the dynamic simulation of a 600MWe oxy-fuel combustion system which consists of cryogenic air separation unit (ASU), pulverized coal-fired boiler and flue gas processing unit (FGU). At the beginning, a steady-state model, using a mixture containing hydrocarbon, oxygen, nitrogen and sulfur to substitute the coal, is successfully transformed into Aspen Dynamics model after adding some equipment parameters and control strategies. Then, switching process from air-combustion to oxy-combustion is studied, and some planned disturbances in air in-leakage, load, oxygen concentration, oxygen ratio and recycle ratio are imposed to investigate the effects of these distributed factors on the characteristics of oxy-fuel combustion system. The simulation running on the common simulator Aspen Dynamics is very useful to gain an insight into the dynamic behaviors of the complete oxy-fuel combustion system.