The Air Distribution And Optimizing Expert System In Power Station Coal Fired Boiler

Coal-fired thermal power dominance in the electric power production，it always consumelarge amounts of coal resources and also produce a great pollution. Boiler is one of the mostimportant part in the thermal power plant,its working status has a great influence in the wholeoperation of the power plant’,that is because the boiler has a complex system structure and aunstable conditions,so it has been a device with the most problems and the highest accidentrates in the power plant running. In the actual operation process, the power plant boiler willoften appear many problems,such as Combustion instability, low combustion efficiency andFurnace slagging, etc. That is directly affect the safety and economy of the boileroperation.Therefore,a reasonable adjustment of boiler combustion conditions is very importantfor boiler operation cost and reduce pollutants discharge. At present most of coal-fired powerplant for boiler combustion adjustment is based on some boiler related parameters relative tothe traditional mode of operation,such as the fan speed, the wind gate position,once andsecondary air wind pressure, the speed of coal supply machine, the oxygenation of the furnaceand the furnace draft,etc. When the wind powder proportion of burner or the pulverized-coalconcentration of primary air pipe is changed, because of the lack of accurate monitoring device,only by experience it hard for operators to adjust the boiler combustion reasonably. Leading tothe boiler run under the unreasonable condition of the air distribution, causing unstablecombustion, the flame center deflection and reduced local coking, boiler efficiency and a ductwall tube etc. It will serious impact on security and economic operation of the unit. Therefore, itis very necessary to real-time optimization adjust the combustion condition of the boiler byreasonable air distribution, and make the boiler can quickly achieve stable combustion,the lesspollution and high efficiency when the coal quality and load is changed.Because boilers often run in the condition of unreasonable ratio of air and pulverizedcoal,we designed the air distribution and optimizing expert system in power station coal firedboiler through pulverized coal, reasonable air distribution, expert guidance and othermeasures.Based on performance characteristics under the various working conditions and theInteraction between working conditions, it chooses the speed of coal supply machine, the coal powder flow, the fire box temperature, the furnace draft,the main steam pressure,the load, thepulverized-coal concentration,the blower speed, the exhaust gas temperature,the exhaustoxygen levels, the feed-water temperature and the feed water flow as the key parameters of theWorking condition of identification. And use the correct and reasonable methods for featureextraction of these feature. This paper used the methods such as fuzzy reasoning to distinguishof The operation condition of boiler. Based on the case-based reasoning expert system is alsoused in fault diagnosis and operational guidance.In terms of air distribution optimization expert system, it uses some tools andtechniques,such as Siemens PLC, VISUAL BASIC, SQL Server, OPC, ADO, etc.what’smore,the data storage uses a relational database and the knowledge base of this system isestablished,it can realize knowledge base rules of add, modify, and delete functions.We have solved the following problems in power station coal fired biolers: First, the lowefficiency of the boiler combustion, large consumption of coal, high operating costs. Second,poor combustion conditions of coal-fired power plants and large pollutant emissions.