Colliery Explosions and Coal-Dust

How does limestone rock dust prevent coal dust explosions in coal mines?

Coal dust explosions in underground coal mines are pre­ vented by a generous application of rock dust (usually lime­ stone). If an explosion should occur, the rock dust disperses, mixes with the coal dust and prevents fl ame propagation by acting as a thermal inhibitor or heat sink. To investigate this process in more detail, a number of ex­ plosion experiments using various coal dust and limes...

Frequency and Causes of Grain Dust Explosions

Grain dust explosions at elevators are in reality a series of explosions. The first explosion referred to as the "primary explosion" is usually small with pressures less than 2 pounds per square inch, (psi). It propagates a pressure wave and fire front. The pressure wave moves away from the location of the primary explosion at a speed of about 1000 feet per second (fps) while the fire front fol...

Effect of Radiation Heat Loss and Ventilation on Dust Explosions in Spherical Vessels

The flame propagation through a coal dust-air mixture in a spherical vessel was studied by means of a one-dimensional, Arrhenius-type kinetics and quasi-steady model. The model includes the evaporation of the volatile matter of dust particles into a known gaseous fuel (methane) and the single-stage reaction of the gas-phase combustion. Effect of venting devices as safety idea and the radiation ...

Transition from Deflagration to Detonation in Layered Dust Explosions

Dust layers on the bottom of mine tunnels, on fac toy floors, or on the floors of gruin elevator passages are the most frequent cause of highly destructive dust explosions. Typically, such layered dust explosions involve a high velocity, acceleruting, turbulent flame which is fed by the dust layer and results in high clestructivt' static and dynamic pressures. In some cases transition to detona...

Airborne Dust Liberation During Coal Crushing