Solution to dust removal problem of drying equipment
The rise in energy costs and regulations on pollution restrictions, working conditions and operational safety are directly related to the design and selection of industrial dryers. Some of the influences of these design factors (especially suspension dryer designs, such as spray, flash and fluidized bed dryers) have been fully discussed, and these must be taken into account during the selection phase of dryers of all types. factor. Sometimes, in the case of drying equipment that can be processed for different materials and different occasions, these factors must be taken into account at the design stage.
For gases, the drying device can cause contamination due to the elimination of dust. In some places, even steam is not allowed. The general requirement is that the concentration of dust in the exhaust gas is less than 20~50mg/Nm3, and a high-efficiency dust collector must be installed. It is important to be suitable for drying coarse particles under certain conditions. On the other hand, the larger the particles, the longer the drying time. In the drying of the powder material, a cyclone, a bag filter or an electrostatic precipitator is usually used for dust accumulation and gas purification. In other forms, such as when drying a slurry, sheet, etc., the dust only occurs during convective drying of the material. In order to eliminate harmful gas pollution, people can resort to absorption, adsorption or incineration.
For gases, the drying device can cause contamination due to entrainment of dust. In some places, even steam is not allowed.
Recommended system dust removal equipment
Cyclone separator: low cost, effective, easy to clean
Bag filter: medium cost, high efficiency, high operating costs
Electrostatic precipitator: large processing capacity
Cyclone separator + wet dust collector: product recovery, small particle size
Cyclone separators are widely used in convection drying systems and are the primary equipment for collecting products from gases. The cyclone separator has a simple structure and is easy to manufacture. As long as the design is reasonable and the manufacturing is proper, high separation efficiency can be obtained. For gases with high dust content, they can also be directly separated, and the pressure loss is relatively small. There are no moving parts, so they are durable. There are no other disadvantages other than the abrasive material causing wear or fine powder adhesion to the inner wall of the cyclone.
Under normal circumstances, the cyclone separator can theoretically capture powders above 5 μm, and the separation efficiency can reach over 90%. However, in actual production operations, separation efficiency is often degraded due to poor manufacturing, improper installation or imperfect operation management. Generally only 50% to 80%, sometimes even lower.
The cyclone separator, also called a centrifugal force separator, separates the fine powder from the gas by using the centrifugal force generated by the rotary motion of the fine powder gas stream.
Strictly speaking, the movement of the airflow in the cyclone is quite complicated. Due to the agglomeration and dispersion of fine powder, the rebound effect of the wall on fine powder and the friction between particles, the separation mechanism is very complicated, and theoretical research has never stopped.