First, the introduction of dust bag
The dust bag is called the heart of the bag filter. It is generally called the dust bag or the dust filter bag. The dust bag is a key part in the operation of the bag filter. Usually, the cylindrical filter bag is suspended vertically in the dust collector.
A dust collector or dust removal device is a device that separates dust from the flue gas. The bag filter is also called a filter type dust collector. It is a dry type high-efficiency dust collector. It is a dust removal device that uses bag filter elements made of fiber fabric to capture solid particles in dusty gas. The principle of action is that the dust particles are intercepted by the inertial force and the fiber collision when the fiber is wrapped around the filter cloth.
In pulsed and air box type pulse dust collectors, dust is attached to the outer surface of the filter bag. When the dust-laden gas passes through the dust collector, the dust is trapped on the outer surface of the filter bag, and the clean gas passes through the filter material and enters the inside of the filter bag. The cage inside the filter bag is used to support the filter bag to prevent the filter bag from collapsing, and it helps to remove and redistribute the dust cake.
The fabric and design of the dust bag should be as efficient as possible, easy to dust and durable. The selection of dust bag is very important, it directly affects the dust removal effect of the dust collector. The dust bag is selected from the following aspects: gas temperature, humidity and chemical, particle size, dust concentration, filtration wind speed, clear Dust methods and other factors.
Second, the working principle of the dust bag
The bag filter is a dry dust collector suitable for capturing fine, dry, non-fibrous dust. The filter bag is made of woven filter cloth or non-woven felt. The dust-containing gas is filtered by the filtering effect of the fiber fabric. When the dust-containing gas enters the bag filter, the particles with large particles and large specific gravity are settled due to gravity. Down, it falls into the ash hopper, and when the gas containing fine dust passes through the filter material, the dust is retained and the gas is purified. Generally, the dust removal efficiency of the new filter material is not high enough. After the filter material is used for a period of time, due to the effects of sieve filtration, collision, retention, diffusion, static electricity, etc., the surface of the filter bag is covered with a layer of dust. This layer of dust is called the primary layer. During the subsequent movement, the initial layer becomes The main filter layer of the filter material has a corresponding increase in the rate and resistance of the primary layer. When the pressure difference between the two sides of the filter material is large, some fine dust particles that have adhered to the filter material are squeezed past. The efficiency of the dust collector is reduced. In addition, the excessive resistance of the precipitator will significantly reduce the air volume of the dedusting system. Therefore, after the resistance of the precipitator reaches a certain value, it should be cleaned in time. The initial layer should not be destroyed when cleaning, so as to avoid the efficiency drop. The structure of the bag filter is mainly composed of an upper body, a middle case, a lower case (ash hopper), a cleaning system and a ash discharge mechanism. The performance of the bag filter is not only the correct choice of the filter bag material, but also the deashing system plays a decisive role in the bag filter. To this end, the cleaning method is one of the characteristics of the bag filter and an important part of the operation of the bag filter.
Third, the structural design of the dust bag
Dust bag is generally divided into pulse dust filter bag, vibrating dust bag and back blow dust bag according to the cleaning method.
Depending on the shape, there are round bag type, flat bag type, and envelope type.
Dust bag also has different bag mouth and bag bottom design options.
Fourth, the application of dust bag
Flue gas treatment dust removal system in ironworks, steel mills, ferroalloy plants, refractory plants, foundries, power plants, etc. Flue gas filtration of waste incinerators, coal-fired boilers, fluidized bed boilers, etc. Asphalt concrete mixing, building materials, cement ceramics, lime, gypsum and other production sites. Smelting flue gas filtration of aluminum electrolysis, lead, tin, zinc, copper and other rare metals, fine material recovery, liquid and solid separation. Liquid-solid separation and fine material recovery in the fields of chemical industry, coke, carbon black, dyes, pharmaceuticals and plastics. Dust management and purification collection for mining, food processing, flour, electronics, wood processing, etc.