Dust explosion detector

Dust explosion refers to the phenomenon where combustible dust, within the explosion limit, encounters a heat source (open flame or high temperature), and the flame instantly spreads throughout the entire mixed dust space. The chemical reaction rate is extremely fast, and a large amount of heat is released, resulting in high temperature and pressure. The energy of the system is converted into mechanical energy and radiation of light and heat, which has strong destructive power.

Dust explosions often occur in production and processing sites accompanied by aluminum powder, zinc powder, aluminum processing grinding powder, various plastic powders, intermediates of organic synthetic drugs, wheat flour, sugar, bakelite ash, milk powder, sawdust, dyes, tea powder, tobacco powder, coal dust, plant fiber dust, etc.

The difficulty of dust explosion is related to the physical and chemical properties of dust and environmental conditions. It is generally believed that substances with higher combustion heat are more prone to explosion, such as coal dust, carbon, sulfur, etc. Substances with fast oxidation rates are prone to explosion, such as magnesium powder, aluminum powder, ferrous oxide, dyes, etc. Dust that is easily charged can also easily cause explosions, such as synthetic resin powder, fiber dust, starch, etc. These poorly conductive substances accumulate static electricity due to friction with machines or air. When they reach a certain amount, they will discharge and produce electric sparks, forming a source of ignition for explosions.

Dust that is usually less likely to cause explosions includes soil, sand, iron oxide, grinding materials, cement, quartz dust, and dust similar to that after combustion. The chemical properties of dust in this type of substance are relatively stable, so it is not easy to burn. But if this type of dust is generated in oil mist and combustible gases such as CO, CH4, and coal gas, it is also prone to explosion.

Dust explosion can be regarded as the formation of the following three steps: firstly, suspended dust rapidly undergoes dry distillation or gasification under the action of a heat source, producing combustible gases; The second step is to mix combustible gas with air and burn it; The third step is to transfer the heat released by the combustion of dust to nearby suspended or blown dust through thermal conduction and flame radiation. These dust particles are heated and vaporized, causing the combustion cycle to continue. As each cycle progresses, the reaction rate gradually increases, and through intense combustion, an explosion is formed. This explosion reaction, as well as the speed of the explosion flame, explosion wave, explosion pressure, etc., will continue to accelerate and increase, and develop in a leapfrog manner.