The cement industry plays a crucial role in the overall process of social construction and development. Each production step involves the processing and handling of raw materials. As one of the primary methods to effectively prevent dust emissions in cement plants, the ventilation and dust removal system actively employs scientific and efficient dust removal techniques, which will promote the healthy, stable, green, and safe development of the cement industry.
The cement process mainly includes the following dust collection points:
1. Crushing, conveying, and storage of limestone
Limestone is the primary raw material for cement production. After arriving at the factory, limestone undergoes several stages of crushing and storage before entering the next process. There are many dust-generating points in this process
2. Dust removal of waste gas from raw material grinding
The dusty gas in this section contains a high level of humidity, and the moisture poses significant challenges for dust removal in raw material grinding. Therefore, when selecting filter materials, the issue of anti-condensation must be taken into account.
3. Bag-type dust collector for coal mill system
Pulverized coal gas is a flammable and explosive gas. Bag filters used in coal mills must be equipped with measures to prevent combustion and explosion, as well as safe pressure relief measures. The filter bags must use anti-static filter materials.
4. Dust removal of raw material dryer
There are primarily two drying methods: one involves drying during the grinding process, where the drying and grinding processes take place in the same equipment; the other involves setting up a separate drying equipment. The exhaust gas emitted from the drying equipment is the main source of dust emissions in cement plants, especially from clay drying systems. The moisture content of this system is particularly high, with the moisture content in the exhaust gas generally exceeding 15%, and the dew point temperature reaching over 55°C; the dust concentration can reach up to 50g/Nm3. It is necessary to use anti-condensation filter materials, while taking measures for corrosion prevention, thermal insulation, automatic temperature detection and adjustment, etc.
5. Dust removal of rotary kiln
Calcination is the primary process in cement production, and its main pollutant is high-temperature dusty gas. The flue gas contains a large amount of dust with a concentration of 30-100 g/m³. Due to the tall chimney, large volume of flue gas, and high concentration, NOMEX or P84 is generally chosen.
6. Dust removal of shaft kiln
The operating conditions of shaft kiln flue gas, such as dust concentration, moisture content, and exhaust gas temperature, vary greatly; bag filters must accommodate these wide fluctuations, and the selection of filter materials should also be considered.
7. Dust removal of cement mill
The concentration of the cement mill’s exhaust gas is getting higher and higher, sometimes exceeding 1000 g/m3. The filter material should be able to withstand a certain degree of erosion.
8. Dust removal in cement packaging system
The cement packaging system has several dust-generating points, which were previously equipped with standalone dust collectors. The use of general standalone dust collectors and ambient temperature filter materials is sufficient.