What are the reasons for and solutions to the increase in flue gas temperature of coal-fired boiler?

In the boiler operation,the flue gas discharged from the flue gas duct has a certain temperature. However, the abnormal increase of flue gas temperature in boiler's flue gas duct is usually accompanied with other abnormal phenomena. In this regard, corresponding measures should be taken for adjustment based on the reason analysis.

The temperature of flue gas in the boiler's flue gas duct is much higher than normal, and the temperature of primary and second hot air also increases abnormally. Meanwhile, there is also a wide fluctuation of negative pressure in boiler furnace and flue gas duct. The fuel amount required in the whole working process far exceeds the fuel amount corresponding to the actual load, which increases energy consumption.

Based on a comprehensive analysis, there are many reasons such as poor combustion, carbon deposits at the tail, or low oil pressure and poor atomization in the start and stop process of boiler, which causes grease deposits on the heating surface of flue gas duct.

What's more, long-time low-load operation and low flue gas speed cause combustibles accumulation at the end of flue gas duct; or incomplete combustion caused by improper combustion adjustment, coarse pulverized coal, too small air volume and so on, which causes that a lot of combustibles accumulated to burn in the flue gas duct.

Therefore, when it is found that the temperature of flue gas in boiler's flue gas duct abnormally increases, the flue gas duct should be blown first, and the air volume and coal volume in the boiler can be manually controlled.For example, the air volume can be unchanged and the coal volume can be reduced. All the treatment methods should be conducted slowly.

If the inspection confirms that the boiler is reburning, it is necessary to stop the boiler in an emergency, stop the two forced and induced draft fans and close their inlet and outlet dampers, and try to use a soot blower to spray steam into the furnace to extinguish the fire, so that the boiler can be normal as soon as possible.