- Smoke volume
my country’s raw coal has not been selected for classification before use, so many varieties are very mixed, and the coal types are mixed and the content is different. The main reasons are that its calorific value, sulfur content, volatile content and other indicators are difficult to distinguish. China’s high-quality coal types, such as raw coal, lean coal, white coal, etc., have a calorific value of more than 5000 kcal, a volatile content of about 17%, and a small ash content; and the worst coal types, such as coal gangue and mud Carbon, etc., its calorific value is 800-3000 kcal, its volatile amount can reach 50%-70%, and the carbon content is large. It can be seen that the different coal types create differences in calorific value, volatile amount and carbon powder amount. The flue gas is generated after coal is burned. The flue gas enters the dust collector through the pipeline and is called the inlet flue gas. The size of the inlet flue gas affects the service life of the dust filter bag. In the case of a large amount of inlet flue gas, if the filtering area is small and the filtering wind speed is large, the pressure of the dust collector rises, resulting in an increase in the pressure of the dust filter bag, which exacerbates the damage of the dust filter bag. The choice of coal type determines the amount of flue gas, and the amount of flue gas directly affects the service life of the dust filter bag.
- Smoke content
Due to the different coal types, the amount of dust in the flue gas is different. When the dust enters the dust collector, due to the different diameter and lightness of the dust, the large-diameter dust falls with gravity or falls off under the interception of the filter bag. The dust with small particle size generates kinetic energy under the action of wind speed. When the dust is intercepted by the filter bag and accumulated on the cloth bag, the kinetic energy is converted to zero at this time, and it will inevitably have an impact on the filter bag; under the action of the kinetic energy, the dust constantly flushes the filter bag, if the smoke contains a large amount of dust The filter wind speed is high, the filter bag will withstand thousands of times of friction and scouring, so that the fiber on the surface of the filter bag can’t stand the scouring and fall off, which damages the filtration efficiency of the filter bag. Therefore, for the working condition with large smoke and dust content, the wear resistance of the needle felt needs to be considered in order to extend the service life of the filter material itself.
- Soot particles
The dust content of coal-fired flue gas is usually invisible to the naked eye due to its small particle size. When we look at the dust under a microscope, we will find that they have different shapes and irregularities, look like blades, and have different diameters. Not the same.
According to the particle size classification, it can be divided into: coarse dust (particle size greater than 40μm), fine dust (particle size between 10μm-40nm), micro dust (below 10μm). Due to their different particle sizes, the impact force on the dust filter bag is different, and the dust also contains a large amount of acidic and alkaline substances, and their diameters are very small. When intercepted by the cloth bag, the role of the filter wind speed It still can’t fall off, and it remains on the surface of the filter material or enters the inside of the filter material. When combined with water vapor, it will stick to the filter bag, so that the filter material will undergo chemical changes to form corrosion. Therefore, when selecting the filter material, the size of the dust particle size can be used as an indicator for consideration.