How to deal with different dusts collection?

Hygroscopic and deliquescent dusts such as CaO, Na2CO3, NaHCO3, NaCI, etc. are easy to absorb moisture and harden on the surface of the filter bag, or become viscous liquid after deliquescence. It will cause difficulty in cleaning, large pressure loss, and even force the dust collector to fail.

When dealing with hygroscopic and deliquescent dust, the following should be paid attention to:

① Use filter cloth with no lint or lint on the surface. Such as the use of felt filter media. Surface treatment should be carried out. The selection principle is:
a, chemical fiber>glass fiber, fine, short, crimped fiber> thick, long, smooth fiber;
b. Felt > fabric, brushing on the surface of the fabric is also a measure to improve wear resistance;
c. Post-treatments such as surface coating and calendering can also improve wear resistance. For glass fiber filter materials, silicone oil, graphite, and PTFE resin treatment can improve wear resistance and folding resistance.
②The offline ash cleaning operation system should be adopted. During the stoppage time, fully remove the dust on the surface of the filter bag.
③The bag filter should be started after the facilities that generate dust are started. When dust is attached to the filter cloth, the moist air cannot be allowed to pass through.

Many high-temperature and high-humidity gases, when the bag filter is stopped, the temperature drops, the humidity rises, and the dust is easy to absorb moisture. A small hot air generator should be connected to the dust removal equipment. When the dust collection is stopped, the hot air can be continuously sent to keep the internal temperature of the bag filter as it is.

Pre-coating: First put other powder materials into the dust collector, after running for a period of time, a layer of this kind of dust is attached to the filter cloth, and then the wet dust that needs to be collected is collected.

It is difficult to treat gases containing tar mist with baghouses. If there is not much oil mist in the dusty gas and there is a considerable amount of dust, it can be filtered.

For example, in an asphalt concrete plant, the flue gas from the stone dryer is the main source, plus the dust from the conveyor and other exhaust gases all enter the bag filter, in addition. At the mixer and at the discharge of the finished material. The tar mist produced by the heated asphalt concrete also enters the baghouse. In this case, the amount of dust accumulated on the filter cloth far exceeds the amount of oil mist, which can prevent the trouble of oil mist sticking and ensure the stable operation of the bag filter.

In the production of electrodes and molded carbon products, tar mist is also generated in the process of mixing powder into a thermal binder. At this time, if the main purpose is to deal with the dust generated during pulverization and transportation, and only a part of the tar mist is mixed in, the bag filter can be used.

However, if the flue gas of the coke tank on the tail tar furnace contains a lot of tar, an appropriate amount of coke powder should be added before the flue gas enters the dust collector to absorb the coke mist, and then satisfactory results can be obtained.

If the gas contains only a small amount of oil mist, it can be treated separately. That is, adding an appropriate amount of powder to the pipeline as a filter aid, the bag filter can be used. After the added dust has absorbed the tar mist, it should be used back in the manufacturing process as far as possible.

To deal with gas with high dust concentration, cyclone dust collector or gravity dust collector can be installed as pre-dust removal. However, this increases the resistance of the system and increases the power consumption. Therefore, when the dust or finished materials do not need to be classified, most of them directly use the bag filter.

Not all baghouses can handle gases with high dust concentrations. Only the bag filter with wide filter bag spacing and continuous dust cleaning device installed outside the bag is suitable for handling gas with high dust concentration.

When dealing with high dust content, the structure of the bag filter should try to make the dust fall directly into the ash hopper or add some baffles to reduce the amount of dust attached to the filter bag; to prevent friction damage to the filter cloth, it should not be used. Make the high-speed moving dust directly impact the filter cloth.

 

The bag filter used for collecting dust in the pneumatic conveying device has less air volume, high dust concentration, and the box requires pressure resistance, so there are more cylindrical shapes. Conditional enterprises can use plastic sintered plate dust collectors instead of bag dust collectors.
The inlet of the cylindrical box is made in a tangential direction, so that it has a separation effect. Sometimes the hopper section is made in the form of a cyclone.

For the bag filter of the pneumatic conveying system, due to the large amount of powder, the volume of the ash hopper and the diameter of the ash discharge port should be designed to be larger, and the capacity of the dust discharge device should also have sufficient room to avoid the retention of powder in the ash hopper. material.