Dust experiment: dust can also explode

Dust explosion is the explosion of flammable dust floating in the air and encountering a certain amount of energy from a fire source. Coal dust explosions in coal mine tunnels are typical of dust explosions. In an open space, dust explosions are less likely to occur, but flour, starch, sawdust, etc., will encounter flash fire at a certain density, causing fire.

Experiment 1 : Dust explosion in a confined space

Before the experiment began, the power to control the course of the experiment of dust explosion, firefighters prepared two small transparent acrylic box, common in daily life of three kinds of powder - flour, starch, putty powder, 1 set of remote controlled electronic ignition device.

After the start of the experiment, the firefighters on-site demonstrating the experiment first placed part of the starch on a flat plate, then covered the starch on the flat plate with a transparent acrylic box, and then one end of a plastic pipe was connected to the bottom of the box and the other end was connected. To the compressed air bottle, the starch in the acrylic box was blown by slowly opening the valve of the compressed air bottle and quickly filled the entire interior of the box.

Just a few seconds later, part of the powder began to overflow from the gap at the bottom of the box. The firemen immediately pressed the button of the remote electronic ignition device. An immediate fire, such as a match light, immediately appeared in the box, followed by a flame tumbling in the box. With a loud bang, the box was slightly lifted and the shock wave blew the fire out of the box.

Afterwards, the firefighters also experimented with flour, putty powder and sawdust. The effect of field experiments was similar to that of starch.

Experiment 2 : Open space dust explosion

This experiment simulates the fact that the powder was scattered on the open fire stove during cooking in the kitchen.

After the experiment began, the firefighters poured starch on a bedside table about 60 cm high, and then ignited the newspaper next to the bedside table. After the flame was stabilized, the valve of the compressed air bottle was opened, and the starch on the nightstand was blown through the plastic pipe to the flame. Upper position.

I saw that the powder that was blown out formed a thick layer of dust in the air. When the dust mass came into contact with the burning flame, the white dust mass immediately ignited and burned rapidly in the air, forming a large fireball and burning heat waves. Fight.

Subsequently, firefighters also used the same experiment with flour, putty powder and sawdust, and the effect of flashover was still obvious.

The principle of dust explosion is that flammable dust is suspended in air at a certain concentration. When a heat source (open flame or high temperature) is encountered, the flame spreads instantaneously throughout the mixed dust space and releases a lot of heat, forming a very high temperature and large The pressure, the overall energy instantly transforms into mechanical energy and light and heat radiation, and has a strong destructive power.

In daily life and production, it is necessary to pay attention to ventilation to prevent the accumulation of dust particles in the room and prevent the dust from reaching a certain concentration. In daily life, avoid cooking on the stove top and mix powder. Once the powder is scattered, it is easy to cause accidents. Enterprises in the production process can take appropriate safety measures to prevent the occurrence of dust explosions, such as closed equipment, ventilation, dust, ventilation, vacuuming, wetting and dust reduction, cleaning dust, control power, static electricity, isolated fire source. When the firefighting force is fighting against dusty fires, it is not necessary to make the deposition dust fly. Spraying water should be used to prevent secondary explosions.

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.