Research On The Application Of Predictive Control In The Selective Catalytic Reduction Denitration System In Power Plant

At present the coal-fired power unit is used widely, the nitrogen oxide (NOx) is the main pollutant in the combustion process of the coal-fired power. Along with increasingly importance to environmental problems and more strict requirements of NOx emission, coal-fired boilers widely use all kinds of technologies to control the emission of nitrogen oxide. The selective catalytic reduction(SCR) denitration technology was widely applied because of its high efficiency of denitrification and technology maturity. But because the application time of SCR technology was quite short, many problems should be solved in its operating process. In order to improve the control quality and precision, a SCR fume denitrification system of certain600MW supercritical boiler was used as the research object, using the predictive control algorithm to control the concentration of its export of nitrogen oxides in this paper. Based on lots of data from DCS records about SCR system, the method of least squares was used to identify the process model of SCR. A predictive controller was designed in the matlab software, which was applied to control the identified model of export concentration of nitrogen oxides in SCR, and the whole control process was simulated. Simulation results show that, the control effect of applying predictive control is better than the traditional PID control in dynamic characteristics and capacity of resisting disturbance, control qualities were promoted. This method has very important significance in reducing the operation cost of SCR flue gas denitrification and energy-saving emission-reduction of power plant.