What you have to know about dust explosion prevention
Dust explosion refers to a dust cloud formed by combustible dust mixed with air in a confined space. Under the action of an ignition source, the formed dust-air mixture burns rapidly and causes a chemical reaction in which temperature and pressure rise sharply.
In recent years, dust explosions are mostly accompanied by aluminum powder, magnesium powder, aluminum processing and grinding powder, various plastic powders, intermediates of organic synthetic drugs, wheat flour, sugar, wood chips, dyes, bakelite ash, milk powder, tea leaves Production and processing sites where powder, tobacco powder, coal dust, plant fiber dust, etc. are produced.
Dust explosion usually requires the following five factors:
01 The dust itself is flammable or explosive;
02 The dust must be suspended in the air and mixed with air or oxygen to reach the explosive limit;
03 There is enough heat energy to cause a dust explosion, that is, the ignition source;
04 Dust has a certain degree of diffusion;
05 Enclosed space (containers, rooms, buildings, pipes).
The explosion of dust is formed by the following three steps:
01 The suspended dust is rapidly dry-distilled or gasified under the action of the heat source to produce combustible gas;
02 Combustible gas is mixed with air and burned;
03 The heat released by the combustion of dust is transferred to the suspended or blown dust nearby by means of heat conduction and flame radiation. After the dust is heated and vaporized, the combustion continues cyclically. As each cycle progresses successively, the reaction speed gradually accelerates, and through violent combustion, an explosion is finally formed. This explosive reaction, explosive flame speed, explosive wave speed, and explosive pressure will continue to accelerate and increase, and will develop in a leap.
What are the commonly used protective measures or schemes to deal with dust explosions?
There are five main types: anti-static, anti-explosion, explosion venting, explosion suppression, and explosion-proof. The main protective equipment involved in the above five schemes includes:
Explosion Isolation Valve
Explosion Suppression Systems
In practical applications, not every protective measure is used alone, and a variety of protective measures are often used in combination to achieve more reliable and economical protection purposes.