Control Strategy Research For Desulfurization Of Circulating Fluidized Bed Boiler

Worldwide in recent decades, a new type of clean combustion technology the rises. The technology demands relatively broad types of fuel, and it has good steady performance. Ash utilization is more easily than ordinary combustion mode, Atmospheric pollutants concentration is low. In recent years, under the environment of energy saving and environment friendly policy, circulating fluidized bed unit, with its remarkable economic benefit and environmental benefit has been widely promoted. Circulating fluidized bed furnace desulfurization system, as an important component of the circulating fluidized bed unit, is with features of less equipment investment, low operation cost, small occupying area, high desulfurization efficiency but it also has the features of pure time-delay, large delay, and parameters time varying. Traditional control algorithms can’t balance the desulfurization efficiency and the economy of desulfurization process.Therefore, based on the desulfurization principles of circulating fluidized bed unit, the influence factors of desulfurization efficiency and the object characteristics of desulfurization process, in application of advanced control algorithm, this thesis will design and simulate for in-furnace desulfurization control system. Internal model control is with good control effect for the object with the characteristics of pure time-delay, large delay, parameter time-varying. And the in-furnace desulfurization system is this kind of object. In this thesis,3 kinds of in-furnace desulfurization control system are designed, based on internal control, and considering the limitations of internal model control algorithm. The 3 kind of system are: in-furnace desulfurization internal model control system, in-furnace desulfurization variable filter parameters internal model control system, in-furnace desulfurization fuzzy internal model control system.In the application of the designed control system, it makes control simulation to identified object of the in-furnace desulfurization. And it compares the control effect with the traditional PID control algorithm of the control system response speed, overshoot and adjustment time, and robustness. The result of simulation shows that the designed control system is with superiority in improving the quality of system control.