1878 On May 2nd, Washburn, the largest flour mill in the world, was in full swing in Minneapolis, Minnesota. Suddenly, the factory exploded and a mushroom cloud rose from the ground. Twenty-two people died and five mills were completely destroyed. The main component of flour is starch, a carbohydrate composed of sugar molecules, which is very easy to burn. Flour particles are very small, each cubic meter of air contains about 50 grams of flour dust, which will burn immediately when exposed to an open flame.
Sprinkling flour on a flame will explode. Why? To make matters worse, when a grain of flour burns, it transfers heat and flame radiation to nearby suspended or blown dust, which will also burn when heated and vaporized. The reaction speed is gradually accelerated, and finally an explosion is formed through violent combustion, and a large number of toxic gases will be produced seriously. This continuous and violent combustion phenomenon is also called dust explosion.
Flour explosion only needs to meet four conditions: proper concentration of combustible dust such as flour; Dust is suspended; A certain oxygen content; The temperature reaches the lowest ignition point of the material. So we must remember not to pour flour in the kitchen with an open flame. In addition, scientists have done experiments. When the raised flour meets the flame, the flame immediately jumps up. The researchers replaced flour with starch and coffee powder, and the result was the same. Experiments show that when we turn on the gas stove, don't sprinkle any powder!