1. the use of temperature
For bag filter, the use temperature depends on two factors, the first is the maximum temperature of the filter, and the second is that the gas temperature must be above the dew point temperature. At present, due to the large number of glass fiber filter materials used, the maximum use temperature can reach 280°C. Gas cooling measures must be taken for gases above this temperature, and measures must be taken for gases below the dew point temperature.
For the bag filter, the relationship between the use temperature and the dust removal efficiency is not obvious. This is different from the electrostatic precipitator. For the electrostatic precipitator, the temperature change will affect the specific resistance of the dust and other factors that affect the dust removal efficiency.
2. Precipitator processing air volume (Q)
The processing air volume refers to the volume of gas that the dust collector can purify in a unit of time. Units are cubic meters per hour (m3/h) or standard cubic meters per hour (Nm3/h). It is one of the most important factors in the design of bag filter.
When the bag filter is designed or selected according to the air volume, the filter cannot generally be operated under a predetermined air volume. Otherwise, the filter bag is easily clogged, the service life is shortened, the pressure loss is greatly increased, and the dust removal efficiency is also reduced; however, it is not possible. If the air volume is too large, it will increase equipment investment and floor space. Reasonable choice of processing air volume is often determined based on process conditions and experience.
3. operating pressure
The operating pressure of the bag filter is determined according to the static pressure value and the installation position of the device before and after the dust collector and the fan, and is also the design pressure value of the bag filter. Inlet dust concentration
That is, the inlet dust concentration, which is determined by the process of the dust point, is an important factor second only to the air volume when designing or selecting a bag filter. Expressed in g/m3 or g/Nm3.
4. export dust concentration
The dust concentration at the outlet refers to the discharge concentration of the dust collector. It means that the method is the same as the dust concentration at the inlet, and the size of the dust concentration at the outlet should be based on the local environmental protection requirements or the requirements of the user. The discharge concentration of the bag filter can generally reach 50 g. /Nm3 or less.
5. pressure loss
The pressure loss of bag type dust removal refers to the pressure drop, or resistance, of the gas from the inlet to the outlet of the dust collector. The pressure loss of bag dust depends on the following three factors:
(1) Pressure loss of equipment structure.
(2) pressure loss of the filter material. With the nature of the filter (such as porosity, etc.).
(3) Dust layer pressure loss accumulated on the filter material.
6. The inlet dust concentration will directly affect:
(1) Pressure loss and cleaning cycle. As the inlet concentration increases, the ash deposition speed on the same filter area increases and the pressure loss increases. As a result, the number of cleaning operations has to be increased.
(2) Wear of filter bags and boxes. In the case of dust with strong abrasiveness, the amount of wear can be considered to be proportional to the dust concentration.
(3) It is not necessary to collect dust in advance. Pre-collecting dust is to add a dust-removing equipment before the entrance of the dust collector, also called pre-dusting.
(4) The ash discharging capacity of the ash discharging device. The ash discharging capacity of the ash discharging device shall be based on the ability to discharge all received dust, and the amount of dust is equal to the inlet dust concentration times the treated air volume.
(5) Operation method. Bag filter is divided into positive pressure and negative pressure operation modes. In order to reduce fan wear, it is not advisable to adopt positive pressure operation mode for large inlet concentration.
