Monitoring of spraying in semi-dry desulfurization processes in coal fired power plants

The overall objective of the study is to improve usability and efficiency of desulphurization processes by providing assistance for plant operators by indicating arising issues. This paper introduces an indirect method to monitor spraying in semi-dry desulphurization processes, which is based on energy balance and first principle models. The method can e.g. be used to estimate flue gas exit temperature of the rector, which is the main control variable in the process, and slurry flows to reactors. The temperature estimate indicates what should be the exit temperature if spraying is functioning properly. The method was tested with process data collected from an industrial power plant, and the simulation results state that the method is able to predict the reactor exit temperature by error of typically less than few degrees Celsius regardless of the process state.