Protection measures for dust bag filter

1. Avoid the dust filter bag of the bag filter from being harmed by oil mist

For example, the coal-fired boiler industry will put fuel oil when starting the bag filter and reducing the load to operate the bag filter. At this time, there is a large amount of oil mist in the flue gas of the bag filter, which will directly endanger the service life of the bag, and certain preventive measures are required. . The dust-laden flue gas conditions of the bag filter under the two conditions are slightly different. When the bag filter unit is started, it mainly relies on fuel ignition to heat up. Under the load-reduced operation condition of the bag filter, the fuel is used as a combustion aid. The temperature of dust removal equipment and pipes is high, and the damage to the bag of the bag filter is relatively light. Therefore, water- and oil-repellent dust-repellent bags or film-coated dust-repellent filter bags should be used.

2. Prevention and measures to the harm of high temperature flue gas of bag filter

When the temperature of the dust-laden flue gas of the bag filter is higher than the temperature that the bag hand can bear, it is necessary to take cooling measures for the flue gas of the bag filter. There are two specific cooling measures:

Cooling by cold air: There is an automatic control valve for ventilating low temperature air (generally the atmosphere) on the flue in front of the inlet baffle door of the bag filter. Under normal circumstances, the valve is closed. When an abnormal working condition occurs (the smoke temperature of the bag filter exceeds the temperature that the bag can withstand), the door is automatically opened to cool down the bag to protect the bag. In this method, it should be noted that the position where the cold air enters the bag filter should be as far away from the bag filter as possible, because generally the smoke velocity is relatively high, and the cold and hot air in the bag filter must be fully mixed to achieve the cooling effect.

Water mist cooling: There is a set of atomizing nozzles for cooling in the inlet valve flue of the bag filter, and the connecting pipe of the nozzle is connected to the pressure water source through an automatically controlled solenoid valve. When the dust-laden flue gas of the bag filter is higher than the temperature that the bag can withstand, the solenoid valve is automatically opened, and the nozzle sprays water mist to absorb the heat of the flue gas. If this measure is adopted, it should be noted that the farther the nozzle is from the bag filter, the better, because the bag filter generally has a relatively high smoke velocity, so that the atomized water droplets of the bag filter can be fully mixed with the flue gas to vaporize and absorb heat. In order to achieve the cooling effect of the bag filter.

Waste heat utilization: flue gas is the main way for general energy-consuming equipment to waste energy. It is to convert the heat carried by the flue gas in the bag filter into usable heat in some way. In the flue of the kiln, the waste heat of the flue gas is recovered and heated into air. The waste heat recovery device of the heat pipe is suitable for large-scale industrial kilns. The equipment is easy to install, safe and reliable, and has a long service life, which can improve energy saving.

3. Prevention and measures to the harm of low temperature flue gas of bag filter

When the temperature of the dust-laden flue gas of the bag filter is low, the flue gas may condense. Condensation occurs, at this time, the amount of water spray should be reduced, or the drying system should be increased to minimize the occurrence of condensation. It is necessary to take measures to heat up the flue gas and to keep the bag filter warm. In the daily use of the bag filter, it is necessary to ensure that the dust-containing flue gas of the bag filter is higher than the dew point temperature by more than 20 °C.