Research On The Automatic Feed Water Control System In Circulating Fluidized Bed Boilers

Circulating fluidized bed boiler technology develops rapidly in recent decades,which is high efficiency and low pollution.The object of study in thesis are feed water control system of 2*300MW CFB in Ning Xia Guo Hua Ning Dong Power.The switch of whole-process control are still manual operation in Corporation by now,so the achievement of automatic feed water control is of great significance,The thesis study in the aspects that water level signal inaccurate,undisturbed switching scheme insufficiency and the control system parameter setting,etc.(1)We analyze the issue of inaccurate boiler water level of CFB and put forward the improvement measures for the accuracy of the boiler water level from signal measurement,signal transmission and operation mode aspect.The application show that the improvement of boiler water level signal meet the requirements.(2)We analyze the dynamic characteristic of the feed water control and put forward the scheme that using single pulse feed water control system or three impulse water supply control system according to the load.The optimizing switch and tracking scheme is propo sed after analyzing the insufficient in process of single pulse and three pulse switch and automatic tracking and hand switch.(3)We set the control system parameter for single pulse and three impulse by the method of attenuation curve and optimize the parameters through trial and error method,the application show that the optimized parameters meet the requirements of the feed water control.In brief,we put forward countermeasures in thesis to improve the accuracy of the boiler water level,we make the switching scheme of single and three impulse water supply control system and set the parameters of the controller.The optimization results show that the proposed control strategy has good effect and improve the efficiency.