Research And Engineering Application Of Predictive Control Algorithm For SCR Denitrification System Of Coal-fired Unit

Selective Catalytic Reduction(SCR)has high denitrification efficiency and is widely used in denitrification systems in power plants.As the country’s requirements for atmospheric NOx emission standards are increasing,coal-fired power plants have higher and higher control requirements for SCR denitrification systems.It is necessary to ensure that NOx emissions meet national standards and prevent airborne emissions caused by excessive ammonia injection.The pre-device is blocked.However,most of the current SCR denitrification control strategies used in power plants can only achieve better control effects under stable operating conditions,and the control effects under dynamic operating conditions such as unit lifting load and coal mill start and stop are often unsatisfactory.Therefore,designing a precise ammonia injection SCR denitration control system has become an urgent problem to be solved.In this paper,by analyzing the reaction mechanism of th e SCR denitrification system and combining the actual operating data,a mechanism model of the SCR denitrification system is established.According to the established mechanism model,dynamic matrix control is adopted to design the predictive control strat egy of SCR denitration system.The effectiveness of the designed control strategy is simulated and analyzed,and it is further applied to the actual operating unit.The main research arrangements of this paper are as follows:(1)The research status of modeling and control methods of SCR denitrification system is reviewed.(2)By analyzing the reaction principle of the SCR denitrification system,based on the original kinetic equation,introduce the critical NH3 surface coverage,establish an improved mechanism model,and verify the reliability of the model.(3)The established SCR denitrification system mechanism model is taken as the controlled object,the predictive control strategy is d esigned,and the actual operating data of the unit is used to simulate and analyze the control st rategy.(4)The designed SCR denitrification system control strategy is applied to the actual operating unit,and the operation effect of the control s ystem under various working conditions is analyzed.The application results verify the effectiveness of the control strategy.