In today's rapidly developing industry, industrial heating boilers are widely used, so the safe operation of boilers is particularly important. In the operation process of industrial heating boilers, boiler explosion phenomenon may occur due to improper operation, generally two types of furnace implosion and external explosion.
In the industrial heating boiler, the negative pressure in the furnace is too high, and when the limit of the furnace wall structure is exceeded, the furnace wall will collapse inward, which is the implosion phenomenon of the furnace. With the development of large-capacity units and the installation of dust removal and desulfurization equipment and the use of high-pressure head induced draft fans, the possibility of boiler implosion has increased. The main method to prevent the implosion of the furnace is to improve the quality of the residence medium of the furnace in the initial stage after the boiler fire extinguishing and MFT action, usually to slow down the fuel cut (this is opposite to prevent the furnace explosion), increase the air supply volume and reduce the lead, Air volume and other measures. Units with a capacity of 600 MW or more and units with desulfurization and denitration equipment should pay special attention to prevent the high-load fire-fighting of the unit or the equipment to cause an implosion hazard caused by excessive furnace negative pressure on the boiler furnace and the tail flue. The chain protection of the furnace negative pressure low jump boiler and the negative pressure low jump induced draft fan should be considered in the interlocking protection function of the flue gas system. Strengthen the maintenance and repair work of the induced draft fan, desulfurization booster fan and other equipment, and regularly test the inlet regulating device to ensure flexible and reliable operation and good automatic adjustment characteristics of the furnace negative pressure to prevent excessive negative pressure when the unit is in operation or the boiler is extinguished. There must be provisions and accident handling plans to prevent furnace implosion in the operating procedures.
When the flammable mixture accumulated inside the industrial heating boiler is suddenly ignited at the same time, the pressure on the flue gas side is increased due to deflagration, which causes the structure of the furnace wall to be broken, which is called furnace explosion. Through theoretical analysis and production practice, it is indicated that three necessary conditions for furnace explosion in industrial heating boilers are required: First, there are flammable fuels (flammable gases or pulverized coal particles) in the furnace; second, the accumulated fuel and air mixture is explosive and reaches the explosion limit; and third, it has enough energy to ignite the mixture. An accident of a furnace explosion will occur under the condition that these three conditions coexist.