The Research Of Boiler Drum Water Level Control

The boiler is plant important motive force of equipment, the requirement is to supply qualified steam, the boiler Steam adaptive load needs. Therefore, the production process of each main process parameters must be strictly controlled. In order to ensure the security and stability of production, boiler automatic control is very important, of which the drum water level is a very important controlled variables. Due to the boiler water regulation process with nonlinear and instability, delay characteristics of boiler drum water level control put forward higher request.This paper comparatively exhaustive introduce drum water level detection of various conventional instrument and measuring methods, through various measurement methods, and then compare the characteristic analysis obtains the best level detection measures.Review the drum water level control object the dynamic characteristic of traditional drum water level control scheme comparison that produce false level reasons, through comparing three impulse control system that relative to the single impulse and double impulse control system, and its control quality best, can effectively meet the system for power, stability, accuracy requirement, and can effectively avoid the "false water level" phenomenon.In the system of field control application, adopting Siemens company of S7-400series PLC, and use with matching STEP7programming software programming and configuration. Use LAD programming language compiled the on-site control system of software components, completing the data acquisition and processing, realized the water level three impulse PID control, process control and interlocking drum water level automatic protection control etc. Function. Through the configuration software IFIX made human-machine interface, realized the system safety management, interface display, real-time monitoring, control parameters set adjustment, historical trends in the collection, system alarm functions.Finally, according to the boiler control present situation, proposed the parameter self-setting fuzzy control rules, design the adaptive fuzzy PID controller for the drum water level control, overcome traditional control mode of the control effect is not accurate and parameter is very difficult to adjust the shortcomings. MATLAB to the traditional PID control system and adaptive fuzzy PID control system simulation, and the results show that the latter adaptive ability stronger, anti-jamming and robustness, guarantee the stability of water.