The Load Coordinate Control System Of CFBB

Circulation Fluidized Bed (CFB) is becoming the main coal combustion technique all over the world for its attractive advantages of high combustion efficiency,Efficient Sulfur Removal, Low NO2 Emission,fuel flexibility and good load-following capability. High demand of automatic control of CFBB is proposed with its fast commercial development. Study of the control strategy for CFBB is getting more and more important now, especially for national circulating fluidized bed boilers.The existing control system is built based on approximately linearization model or identification model. The model is just depending on the data of process inputs and outputs, so it can't interpret the mechanics of industrial process. So we want to create a new control system base on the mechanics model which have built by own team.Firstly, online calculation for heat to power output efficiency of thermal generator set is important for the load coordinate control in the CFB boiler thermal generator set. Least-square polynomial fitting method is adopted to get a simple expression of steam enthalpy. Based on it, an online algorithm to calculate the heat to power output efficiency is proposed. Simulation is done using the data acquired from an industrial unit, which may provide a basis for further global optimization. And then the influencing factors of the heat to power output efficiency is discussed.Secondly, four kinds of the coal quality online observation system are proposed by applying the BP and RBF neural networks, which take the coal feed, the primary air, the secondary air, the temperature of dense phase and O2 concentration of the dilute phase as inputs. Compared the generalization capability between the BP and RBF networks, and the online coal quality prediction indicates that the online observation systems based on the BP neural network are more effective than the RBF networks. The CFB boiler total model is proposed by composing the CFB boiler system dynamic model and the coal quality on-line observation models (standard BP network and L-M BP network). Compared with the results of the real time simulation of the different CFB boiler total models, the model based on the standard BP network is better than the L-M BP networks.Finally, by combining the CFBB mechanics model, the coal quality online observation system and the concept of the heat to power output efficiency, the simplified system of thermal generator set is built and load coordinate control system base on the coal feed is successfully developed. The result of simulation indicates that control system can meet the need of the engineering application.