The Application Of PLC In The Boiler Ash-blowing Program Control System In Thermo-electric Power Plants

Power plants mostly use coal as fuel.China power coal of poor quality, the amountof ash and sulfur content is higher, the general utility boilers burning coal andever-changing.During the operation of the boiler,the heating surfaces inevitablyencounter fouling problems.The ash depositing and slagging on the boiler heatingsurfaces has great influences on the safety and the economical operation of thecoal-fired boilers in power plants.It at least deteriorates the effect of heat transfer, andworst of all, it may cause the pipes burst and other equipment accidents, and disrupt thenormal production. It is very important to purge fouling and slagging on the heatedsurface periodically,which ensures the safe and reliable operation of the boiler sootblowing system.Establishing a reasonable soot blowers control system, can not onlyreduce the labor intensity of the operator, but also improve the system’s reliability andautomation level.In order to adapt to the development of enterprises, the urgent need to develop alarge-scale thermal power units sootblowing programmable control system, which is ofgreat significance to improve the productivity of enterprises and economic benefits.In this paper, according to the serious and universal pollution problem caused byfouling and slagging of the boiler heating surface,with Shenhua Guohua Sanhe PowerPlant300MW Unit3boiler as subject, researches are conducted on the soot blowingsystem.In order to realize the program-controlled boiler soot blowing system, this papermainly studies the theory and method of power plant coal-fired boiler soot blowingcontrol system.By the use of the software tool Concept2.6, a new program-controlledboiler soot blowing system are established, based on the Schneider programmablecontroller (PLC) and Kingview6.01configuration software. In this paper,we discussedthe functions and features of the control system, and showed the control systemhardware and software design framework, and the associated program modules weredeveloped.The user interface,designed with the software tool Kingview6.01was foundfriendly and easy to use. Operation mode:automatic mode,manual mode or local mode will be selected,according to the location and number of soot blowers arranged.According to the flue gasdirection, soot blowers will run in turn, which can reduce soot blowing impact on theboiler load.After the experimental verification and online debugging, the program-controlledsoot blowing control system has been applied to CSEC Guohua Sanhe Power Plant300MW Unit3boiler.Practice has proved that the program-controlled soot blowingsystem has high reliability, low failure rate and is easy to use, and improve the securityand economy of the plant operation.