The Research Of Steam Temperature Control Strategy In Supercritical Pressure Once-through Boilers

With a large number of applications of supercritical once-through boiler,the reasoned control method is playing an increasingly important role for security and economy. In this paper,a method based on the predictive and adaptive control was designed,which was used in supercritical steam temperature control system.First of all,characteristics of the Steam and water under the super-critical state and dynamic characteristics of steam and water system in supercritical once-through boiler were analyzed and popular and practical control strategy and control method were discussed.Secondly,the mathematical models of economizer,water wall,superheater in the supercritical once-through boiler were established through combining the differential equations and difference equations method.To verify the correctness and availability of model the output of simulation and the actual output was compared.Finally,for supercritical once-through boiler large delay,large inertia of the characteristics,a control method based on the prediction and adaptive control was designed, which was applied to the mathematical model of 600MW supercritical units.Simulation tests show that this method can improve system quickly and enhance the capacity of the control system of anti-disturbance.