Design Of The Utility Boiler System Based On DCS

First of all,the thesis introduce the function and the development trend and characteristics of DCS system. Through in-depth describ the DCS system of Hollysys campany,leading to A power transformation project Anshan Iron and steel group co. and method of the DCS system in control.Background of the thesis is 240 tons of energy power control center of a power boiler project DCS system of Anshan Iron and steel group co.,using to introduce the basic knowledge of DCS, and clarify the process of design and development, so that readers understand the DCS system in control preliminarily. From the boiler control system of main equipment, main feed regulation,warm water regulation,hearth negative pressure reduction of DCS program design to the scene of DCS and hollysys software implementation, it introduce that hollysys DCS system in detail in the control system of the boiler in the power generation is used adequately. In practical project, because of change of the main feed water regulation system, the regulator by the drum water level, water flow and steam flow three signal and the role of interaction,so that water level in the signal of the regulator is changed under the condition of the water level change.We regard the water flow asfeedback signal,so that three impulse signal eliminate the disturbance according to feed-forward signal in the condition that the water level is static,which eliminate impact of "false water level" on control,and succeed to control the amount of water accurately. Warm water reduction system on the level 1 set a monitoring system between superheater and platen superheater, and the level two is same as the level one between high superheater cold forging and hot forging,which control warm water reduction accurately. The operation safely and economically is closely related to boiler negative pressure. If the pressure is too high it will cause leakage of dust so that the risk of explosion, if the pressure is too low power consumption will increase. After consider to use the induced draft fan system of the singlePID, the furnace pressure maintain appropriate values.In the fourth chapter, firstly the PID and fuzzy control theory is briefly introduced.Secondly to offuzzy PID parameter through the fuzzy control method.Finally,to introduce the simulation experiment on industrial boiler bed temperature. Through the comparison of the fuzzy PID with a simple PID, the fuzzy PID is better than a simple PID in any way of overshoot time, response time,steady-state error and other indicators.