What are the materials of the bag filter material used for dust removal in the bag filter
The bag filter material for dust removal is generally divided into three types of materials:
1. Room temperature cloth bag: The main material of room temperature cloth bag is made of polyester, polypropylene, acrylic and other fiber materials through non-woven and textile processes. It has excellent properties such as good breathability, smooth surface, good dimensional stability, and easy dust removal. It is mainly used for dust removal and room temperature smoke control in industries with dust pollution in general industrial enterprises.
2. Medium temperature cloth bag: With the development of bag dust removal technology in recent years, China has started to use imported synthetic fibers and developed high-performance filter materials that can adapt to harsh working conditions and have an ultra long service life. At present, the commonly used medium temperature filter materials on the market include aramid fibers and PPS series fibers that undergo soaking, waterproofing, oil resistance, and corrosion prevention processes to achieve ideal filtration effects.
3. High temperature cloth bags: The commonly used high temperature cloth bags on the market are mainly made of high-temperature resistant fiber materials such as P84, expanded glass fiber, and ultrafine glass fiber, which are processed through textile and non-woven processes. They are characterized by good thermal stability, high filtration efficiency, and long service life. It is mainly used for dust collectors under various high-temperature flue gas conditions, and for parts with harsh working conditions, DWD high-temperature cloth bags are used. Moreover, for ordinary dust collection parts, polyester cloth bags can be used.
When the dust containing gas passes through the filter cloth in the process of bag filter, the gaps between the filter cloth fibers or the gaps between the dust adsorbed on the surface of the filter cloth separate the dust larger than the diameter of the gaps, which is called screening effect. For the new filter cloth, due to the large gap between the fibers, this effect is not significant and the dust removal efficiency is also low. The screening effect is only significant when a certain thickness of dust layer is established on the surface of the filter bag after a certain period of use. After dust removal, due to a certain amount of dust remaining on the surface and inside of the filter bag, good dust removal efficiency can still be maintained. For needle punched felt or fluffy filter cloth, as the felt or fluffy filter cloth itself forms a thick porous filter layer, it can fully exert the screening effect and does not rely solely on the dust layer to maintain high dust removal efficiency.
Pulse cloth bags are the heart of bag filters, mainly used to filter dust. When dusty gas passes through the dust removal bag, the dust is blocked by the bag, and the purified air is sucked away by the induced draft fan. The accumulation of dust on the surface of the cloth bag continues to increase, which increases the resistance of the dust collector. At this point, the pulse controller receives a signal to blow the cloth bag, causing dust to fall into the ash hopper and the dust collector to discharge from the unloader.
Pulse bag dust collectors generally use circular filter bags, which are divided into two types based on the flow direction of dusty gas: circular inlet and bottom inlet. This type of dust collector usually consists of an upper box (clean air chamber), a middle box, an ash hopper, a frame, and a pulse injection device.
The cleaning of pulse blowing is controlled by a pulse controller to open and close the pulse valve. When the pulse valve is opened, the compressed air inside the air bag sprays a high-speed and high-pressure jet airflow through the small hole on the blowing pipe through the pulse valve, forming an induced airflow equivalent to several times the volume of the jet airflow. The airflow enters the filter bag together, generating instantaneous positive pressure and rapid expansion in the filter bag. The dust deposited on the outside of the filter bag will fall and fall into the ash bucket, achieving the purpose of cleaning the ash.
Under the driving force of the fan, the pulse bag dust collector creates a negative pressure environment inside the dust collector, the dust removal pipeline, and the dust removal hood, causing the dust at the dust raising point to enter the dust collector under the pressure difference. The airflow passes through the dust removal filter bag and the dust is intercepted on the surface of the bag. The pulse signal is regularly input to the pulse valve through the pLc controller, and the high-pressure air of the compressed gas blows away the dust attached to the surface of the filter bag and collects it into the ash hopper. In order to achieve the purpose of dust collection, the treated clean gas is discharged from the chimney through a dust removal fan.