Abstract:
To improve the control accuracy of the critical parameters of the MPS coal pulverization system during the loading cycling process, this paper establishes and verifies the dynamic model of the pulverization system and conducts control strategy optimization research. On the basis of the original logic of the pulverizing system, it is proposed to add the primary air temperature control loop at the inlet of the feedforward pulverizer for considering the coal moisture information to improve the control strategy. Simulation research such as the increase of coal moisture, the increase of coal feeding rate, and the load cycling of the pulverizer is carried out. The transient characteristics of key parameters and energy consumption of the pulverizing system are obtained, verifying the proposed strategy's superiority. Research results show that: Once the control logic of the pulverizing system proposed is adopted, the response rate of the system is improved when confronted with disturbances like sudden variations in the feed coal flow rate or abrupt increases in the moisture content of the coal. What's more, the fluctuation range of the pulverized coal temperature decreases by more than 50%, and the transient energy consumption decreases by 2.4%. During the load cycling transient process of the pulverizer, the steady-state energy consumption can be reduced by more than 100 kW, and the energy consumption in the pulverizing process can be reduced by 6.82%. During the transient process, the fluctuation range of the pulverizer outlet temperature can be reduced by 50%, the response time can be shortened by more than 10%, and the maximum transient energy saving can be achieved by 5.43%, which comprehensively guarantees the operation safety of the pulverizing system and reduces the energy consumption. When the optimization control logic of the pulverizing system proposed is applied in a coal-fired power plant, the operation deviations of key parameters, such as load rate and main steam pressure, can be reduced during the load cycling transient process. Thus the operational flexibility of the power plant can be improved.