pneumatic conveyingThe bag filter used for collecting dust is an efficient dust collector, mainly applied in circular bag bag filters. The bag filter in pneumatic conveying systems is designed with a large amount of powder, a larger ash hopper volume and discharge port diameter, and sufficient capacity for dust discharge devices to prevent powder from being trapped in the ash hopper.

      There are corresponding measures for dust removal pneumatic conveying of special dust, such as moisture absorbing and deliquescent dust, which is one of the special dust types. Moisture absorbing and deliquescent dust such as CaO, Na2CO3, Na2HCO3, NaCl, etc. are prone to form a viscous liquid on the surface of the filter cloth after moisture absorption or deliquescence, causing difficulty in dust removal, increased pressure loss, and even forcing the bag filter to stop operating. Attention should be paid to the following matters when dealing with hygroscopic and deliquescent dust:

1. Use a filter cloth with a surface that is free from pilling and pilling. For example, if using felt filter material, surface treatment should be carried out. The selection principle is:

a) Chemical fiber is superior to fiberglass, and expanded fiber is superior to ordinary fiberglass; Fine, short, and curly fibers are superior to coarse, long, and smooth fibers;

b) Compared to fabrics, felt materials use needle punching to enhance the interconnectivity between fibers. Among fabrics, forged fabrics are the best, and the surface of the fabric is brushed to improve wear resistance;

c) Surface coating, calendering, and other treatments can improve wear resistance. For glass fiber filter media, silicone oil, graphite, and polytetrafluoroethylene resin treatments, wear resistance and bending resistance can be improved.

2. Offline dust cleaning operation should be used to fully remove dust on the surface of the filter cloth during the downtime.

3. The bag filter should not be continuously operated regardless of whether the dust source facilities are running. The bag filter should be started only when the dust source is designed to operate. When a dust layer accumulates on the filter cloth, moist air should not be allowed to pass through.

      Many exhaust gases from drying machines and sintering furnaces are high-temperature and high humidity gases. When the bag filter stops running, the temperature drops and the humidity rises, making it easy to absorb moisture. Because a small hot air generating device is installed on the dust removal equipment, so that when the dust source device stops running, hot air can be drawn in to maintain the internal temperature of the bag filter in its original state.

      When dealing with low dust content, a pre coating layer can be used. Other powders can be pre coated on the bag, which only supplies other powders to the pipeline. After a period of operation, a layer of dust adheres to the bag and then wet dust is collected.

       There are corresponding measures for dust removal pneumatic conveying of special dust, such as tar mist and dust containing gas, which is one of the special dust:

      The bag filter is not very effective in dealing with tar gas. When dealing with tar mist that is not large but with a lot of dust, the effect is still quite obvious.

For example, in the asphalt concrete plant, there is a lot of smoke from the stone and dryer, and the dust from the conveyor and mixing station, as well as the discharge of finished materials, and the tar mist generated by the heated asphalt concrete also enter the bag filter. Due to the use of other equipment to produce dust, the amount of dust accumulated on the bag far exceeds the amount of oil mist. This prevents the phenomenon of oil mist sticking, allowing the bag filter to operate stably.

      In the manufacturing of electrodes and formed carbon products, tar mist is also generated during the process of mixing powder into the hot bonding agent. At this point, if dust generated during crushing and transportation is the main focus, bag filters can only be used when only a portion of tar mist is mixed in. If there is a high amount of tar in the flue gas of the coke tank on the tar furnace, an appropriate amount of coke powder should be added before the flue gas enters the bag filter to adsorb coke mist, in order to achieve satisfactory dust removal effect. When dealing with gases with high dust concentration, a cyclone dust collector or a gravity dust collector can be used for dust removal. The high concentration gas can be simply treated before entering the bag filter. But this will increase the system's resistance and power consumption; Therefore, when dust or finished materials do not require classification, bag filters are mostly used directly. Some bag filters cannot handle gases with high dust content. It is possible to increase the spacing between filter bags and install a continuous dust cleaning device on the dust collector to handle gases with high dust concentration. When dealing with gases with high dust content, bag filters generally try to make the dust fall directly into the hopper, reduce the amount of dust on the filter bag, and prevent damage to the bag filter. High speed moving dust hitting the filter bag can cause significant damage.