Active explosion barrier performance against methane and coal dust explosions

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...

Influence of coal dust on premixed turbulent methane–air flames

This study discusses the design of a new experimental platform, the Hybrid Flame Analyzer (HFA) to measure burning velocity of gas, dust, and hybrid (gas and dust) premixed flames. The HFA is used to analyze a particle–gas–air system of coal dust particles (75–90 lm and 106–120 lm) in a premixed CH4–air (/g = 0.8, 1.0 and 1.2) flame. Experimental results show that particles usually increase the...

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...

Explosion dust particle size measurements.

In situ measurements of the sizes and concentrations of dust particles generated by the detonation of high explosives in clay soil near Leesville, La., sandy clay soil near Huntsville, Ala., and sandy soils near Orogrande, N.M. are reported. Measurements were generally made within 1 m of the surface (in one case 10 m) at distances ranging from 10 to approximately 50 m from the detonation point ...

Dust Explosion Propagation: Myths and Realities