Experiment on methane-coal dust explosions

An experimental system including pressure transducer,data acquisition card,computer and electric spark ignition device was set up to experimentally study methane-coal dust compound explosions in confined vessels.Its dynamic response time was less than a millisecond and test precision was 0.5%.The experimental results show that the maximum explosion pressure is quadratic with methane concentration,coal dust concentration and ignition delay time and increases with coal dust size.The most dangerous condition is that the methane concentration is about 5%,the coal dust concentration is about 500 g/m3,and the ignition delay is about 40 ms.Methane reduces the explosion low limit but increases the explosion pressures of coal dust.Also,coal dust reduces the explosion low limit but increases the explosion pressure of methane.