During powder pneumatic conveying, it is important to understand the characteristics of powder explosion
InPowder conveyingWhen suspended in the air, dust must have sufficient oxygen and a suitable range of dust concentration in order to cause dust explosions under the conditions of explosion and ignition temperature
????① Having sufficient oxygen.
????② The appropriate range of dust concentration, that is, the spacing between dust particles, can ensure that the flame can flow freely and extend to the surface of adjacent dust particles, without causing local oxygen deficiency due to the dust particles being too close to each other.
????③ In order to maintain the ignition temperature of dust, there must be sufficient supply of minimum ignition energy.
? ? ? ?The finer the particle size of the dust, the lower the concentration of dust suitable for explosion, and regardless of whether it is aluminum powder of metal or polyethylene powder of organic matter, the concentration of explosion dust tends to remain unchanged when the particle size is below 50 μ m. In addition, the finer the particle size of dust, the higher the result of combustion - the explosion pressure and its rate of pressure rise. The minimum ignition energy and ignition temperature are indicative of the easy ignition and combustion of dust, but combustion is a prerequisite for causing explosions. The finer the particle size of dust particles, the lower the ignition energy. If the concentration of explosive dust decreases, the ignition temperature will increase.
? ? ? The shape of dust particles also has an impact on explosions, and the degree of explosion of thin aluminum powder! More pronounced and intense than granular aluminum powder at the same dust concentration.
The characterization of dust explosion characteristics can be characterized by the following parameters:
?????1) Fire sensitivity. Fire sensitivity=ignition temperature x minimum ignition energy x minimum explosive concentration.
????2) Explosion sensitivity. Explosion sensitivity=maximum explosion pressure x maximum pressure rise rate.
????3) Explosion index. Explosion index=fire sensitivity x explosion sensitivity.
????The inhibitory factors of dust explosion include the effect of water addition rate (mass fraction of water,%) on the minimum ignition temperature, minimum explosive dust concentration, maximum explosive pressure, and maximum pressure rise rate. It can be considered that adding an appropriate amount of water is beneficial for suppressing the ignition, combustion, and explosion of dust
Blow it up. The flow state of dusty air also has a certain impact, such as turbulent flow, which delays ignition and reduces the maximum explosion pressure and maximum pressure rise rate.
? ?Using pneumatic conveying is very safe and efficient. The powder is in the pipeline, which can isolate external factors. If transporting special flammable materials, inert gas can also be used for safer transportation. The pneumatic conveying system has undergone continuous development, and the materials conveyed are becoming more and more extensive. If you needPneumatic conveying equipment Welcome to contact us. We can provide free trial service.