Performance Simulation of Full-scale Wet Flue Gas Desulfurization for Oxy-coal Combustion

Abstract

Abstract Oxy-coal combustion implies significant changes on the power plant design and operation compared to air-firing. In particular, the new operating conditions cause modifications on the process design and performance of the wet flue gas desulfurization (FGD) unit. It has been previously showed at pilot plant scale that high SO2 removal efficiency is achieved and no substantial problems have been observed while operating in oxy-combustion conditions. This study intends to meet the needs for a full-scale analysis of the process performances in order to investigate the wet FGD potential. To do so, a dynamic model already developed in a previous work for air-fired power plants has been adapted to deal with these new process conditions and used to perform an investigation of the wet FGD capability when operating under oxy-combustion conditions. The process design and operating parameters are determined to optimally achieve process performances (energetic, economics). There is no significant difficulty to achieve targeted performance. A conservative SO2 outlet of 200 mg/Nm 3 can be achieve easily both for low and high sulfur coal. Warm recycle increases the oxy-combustion power plant efficiency, reduces the flue gas to be treated but increases the SO2 content by 60%. To cope with this increase inlet SO2, the L/G ratio is increased by 80%; but the investment cost is reduced by 25% compared with cold recycle. Finally, a global design of the FGD+DCCPS equipment is needed in order to achieve optimal performance of the flue gas desulfurization at reasonable cost.