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Optimal baghouse pressure drop

 

The reason to focus on optimizing pressure drops in the dust extraction system is that each excess pascal – pressure loss – is manifested by an increase in operating costs for the operation of the extraction  fan. The pressure losses of the ducts are discussed in a separate chapter. The largest pressure drop of the entire system is caused by the bag filter itself.

To save the operating costs of the dust extraction system, it is most important to choose a bag filter of a design that ensures the required suction power is maintained at the lowest pressure drops of the filter medium.

Cost-effective value: the bag pressure drop is between 500 – 1000 Pa

Acceptable value: the bag pressure drop is between 1000 – 1800 Pa

Operating a bag filter with a pressure drop value above 1800 Pa is very uneconomical, and we recommend that you immediately perform a service inspection of the filtering device.

The difference in power requirements of operation of filtration systems with a pressure loss of 1000 Pa or 2000 Pa with a suction power of Q = 30,000 m3 / h is about 10 kW. With a three-shift operation five days a week, an inefficient bag filter (Δp = 2000 Pa) consumes 62.4MW more in a year than the economical variant (Δp = 1000Pa), which represents an increase in operating costs of about 7000 EUR per year.

Tab. 1: Výkony na hřídeli odsávacích ventilátorů u systému s celkovým tlakem 4000 Pa a 5000 Pa
Fig. 1: Output shaft power for the 4000 Pa and 5000 Pa system

In table Fig.1 we compare two identical suction systems. In the first case (blue color) the required power on the fan shaft is indicated – With the total 3000Pa pressure drop of the ducting pipeline and the 1000Pa baghouse unit. The red curve describes the power required on the suction fan shaft at the same pressure loss of the 3000 Pascals in the pipeline. The pressure loss of the baghouse is in this case 2000 Pa. The differences between the shaft power of the fans are remarkable.

Keep in mind that not only the volumetric airflow value is important when selecting the dedusting system. The total electric power of the baghouse and the fan is as important. Each baghouse´s task is to clean the exhaust air with the most continuous exhaust conditions, however with the lowest electrical power neccessary.