A Study Of Heating Boilers’ Control System

Most cities in northern China adopt coal fired boilers for heating in winter.However, the boilers always work at low efficiency with severe energy waste and substandard emission due to aging control equipment, imperfect anti-pollution measures and laggard run method. It goes against the principle of economical,efficient and little polluted operation. According to the latest research, the rising PM2.5 results from coal burning. With the development of society and living standard,people pay increasing attention to the environment, valuing energy saving and emission reduction of winter heating. Therefore, the automatic operation of heating boilers is of great significance to improve heating status. In the thesis, an energy saving control system for heating in the buildings on and around campus was established based on University of Science and Technology Liaoning’s heating load,property and distribution. The supervision of the system was perfected through designing boilers, pump stations, heating exchange stations, primary pipe network,secondary pipe network and control station monitor. The users’ node temperature measure and the signal transmission via LAN were achieved through the Protocol Converter PD1244. With an emphasis on the control of primary pipe network, a mode of relations among primary pipe network supply, return water temperature and outdoor temperature was established: the supply and return water temperature was obtained by managing the change of outdoor temperature half an hour early.Meanwhile, time-sharing control was adopted considering each building’s heating demands at different time. In the project, the high-configuration computer, which enabled a demonstration of human-computer interface via MCGS software, was applied as the upper one so as to illustrate real-time data, inquire historical data,provide alarms and print reports. The lower computer of the system adopted PLC control to manage the real-time change of response system. Based on four boilers and heat exchange station, the control program was designed to take charge of fire box temperature; exhaust gas temperature; boilers’ outlet water temperature, return water temperature, outlet volume, return volume and inside pressure; heating exchange station’s outlet water temperature, return water temperature, outlet volume, return volume and slag removal system. Meanwhile, the control program provided alarms for boiler inside pressure, fire box pressure as well as water leakage of primary and secondary pipe networks. In total, the project aimed to realize the automatic control and economical burning.