Modeling And Control Of Coordination System For Supercritical Circulating Fluidized Bed Unit

As far as the current energy situation is concerned,coal-fired power generation in China will continue to be the main power generation industry for a long time,and clean coal-fired power generation is the direction of China's power industry.Because of the great advantages of low cost and high efficiency of CFB and supercritical technology,the combination of the two technologies not only has great application value in coal combustion resources,but also has obvious advantages in desulfurization,denitrification and power supply efficiency.Therefore,the control research of the coordinating system of supercritical circulating fluidized bed boiler unit is an important research field to promote coal-fired power generation technology.The operation process of supercritical circulating fluidized bed boiler is complex and changeable,and the coupling is very strong.In this paper,the Coordination Control System of Supercritical CFB Boiler Unit is taken as the object,and the following research contents are mainly carried out:Firstly,according to the process of mass and energy change in the furnace of the coal feeding system of the supercritical CFB unit,the pressure difference of each device on the feedwater side and the dynamic process of the steam turbine operation,the non-linear control model of the boiler side and the steam turbine side of the supercritical CFB unit is established.Based on the historical and actual operation data of 600 MW supercritical circulating fluidized bed boiler units in Sichuan Baima Power Plant,the system identification and parameter estimation of the established non-linear control model of supercritical circulating fluidized bed are carried out.Finally,the accuracy and generalization ability of the model are verified by comparing the simulation curve with the actual curve.At the same time,the non-linear characteristics of the coordinating system of the supercritical circulating fluidized bed boiler unit are studied from the two aspects of step disturbance response and controllable observability.Secondly,in order to further improve the non-linear characteristics of the boiler,the decoupling control design of the coordinated control system of the supercritical circulating fluidized bed unit is analyzed in this paper.By solving the relative gain matrix,the variable pairing is realized in the multi-variable system,and the decoupling control design of the model is realized by using the feedforward compensation decoupling control principle.Finally,the practicability of the design is verified.Finally,according to the basic principle of predictive control,the important parameters in predictive control are analyzed and calculated,and the model is transformed into quadratic programming form by using state space based predictive control,and the optimal control quantity is obtained.Finally,the superiority of the multivariable predictive control system in various comprehensive performance is verified by the actual simulation curve.