There are many dust sources in the cement production process, such as cement crusher, cement mill, cement concentrator, conveyor, cement silo, cement packing machine, cement dryer, coal mill, shaft kiln, cement rotary kiln (kiln head and kiln tail), etc. They all produce a lot of dust during operation. In the past, we applied dust collectors to the cement production line, not for environmental protection, but for materials collecting, consumption reducing, cost-saving, and labor protecting. In cement plant, except electrostatic precipitator is used at the end of cement kiln, cyclone dust collector, settling chamber, as well as some wet dedusters, are all the main dust collecting method applied in cement manufacturing processes. While these dust removers we mentioned above have low efficiency and backward technology, resulting in the loss of cement powder accounted for 7% of the total cement output.
In recent years, the development and use of fiber filtration materials with different properties have expanded the technology of bag filter, which is gradually applied in cement plants. Pulse jet bag filter and blowback bag filter are two frequently used bag filters in cement manufacturing plants. What is their difference? How to select the most suitable model? AGICO will help you to have a deeper understanding of these two filters and find the answer.
The pulse jet bag filter and blowback bag filter are both fabric filters and use compressed air to clean the dust, but their principles are obviously different.
Pulse Jet Bag Filter
The dust gas of pulse jet bag filter enters from the lower part of the equipment body. After filtering, the dust is trapped outside the filter bag and the purified gas is discharged into the atmosphere by passing through the filter bag and the air outlet of the upper chamber. When the dust accumulated outside the filter bag reaches a certain amount, the compressed air will make the filter bag expand at high speed and vibrate at high frequency in a very short time for removing the dust.
Blowback Bag Filter
On the contrary, the dust air of blowback bag filter enters from the upper part of the machine body. After filtering, the dust is trapped on the inner side of the filter bag, and the clean gas is discharged into the atmosphere through an outlet pipe. When the dust accumulated inner the filter bag reaches a certain amount, the exhaust valve will be closed and the blowback valve will be opened so that the originally expanded filter bag is compressed and deformed to achieve the purpose of cleaning dust.
Both the pulse jet bag filter and the blowback bag filter are chamber bag filter with steel structure. But they have many similarities and differences in performance.
- Both of them have a reliable design that not only guarantees a long-term and stable operation but also achieves the best dust removal intensity and effect.
- Both of them have high adaptability to a wide range fluctuation of dust gas properties.
- The special structural design and strict selection of filter materials and components can meet the environmental requirements. Their emission mass concentration is less than 80 mg/ m3.
- Their anti-air leakage design minimizes the air leakage rate.
- The two bag filters both adopt the automatic over-temperature alarm and emergency cooling control system.
Compared with blowback bag filters, the pulse jet bag filter adopts the pulse dust cleaning technology, which has the characteristics of high filtering speed, small volume, less steel consumption, and low cost. While because it uses the special filtering materials, its maximum service temperature should be lower than 130 ℃.
From the perspective of daily maintenance, the pulse jet bag filter has more running parts than the blowback bag filter because it adopts the pulse ash cleaning method, which is more complicated in daily maintenance.
Operation Effect & Economic Benefit
The dust removal efficiency of the blowback bag filter and pulse jet bag filter can reach more than 99%, the air leakage rate is less than 3%, and their dust emission concentration is far below the emission limit of 150 mg/ m3.
Compared with the cyclone dust collector, settling chamber, and electrostatic precipitator, the two kinds of bag filters have higher investment cost and operation cost, but they have good dust removal effect, simple operation and maintenance, and can recover a large amount of cement dust. Taking a 2.5m diameter shaft kiln as an example, using the bag filter can recover 3103 tons of cement dust a year, creating a value of about 50000 US dollars.
AGICO is a professional cement equipment manufacturer with more than twenty years’ experience in the cement industry. Pulse jet bag filter and electrostatic precipitator are our hot sales products that play an important role in the cement manufacturing process. If you are interested in our equipment, please feel free to contact us!