Hybrid CH4/coal dust explosions in a 20-L spherical vessel

Explosion characteristics and influential factors of hybrid CH4/coal dust explosions are studied using a 20-L spherical explosion vessel. Experimental results show that the maximum explosion pressure and maximum rate of pressure rise increase in the initial phase and then decrease as the coal dust or CH4 concentration increases. The optimum concentrations of coal dust and CH4 are 200 g/m(3) and 5 vol.%, respectively, when the initial pressure is equal to the atmospheric pressure. Moreover, the maximum explosion pressure keeps rising with the increasing initial pressure, and the maximum rate of pressure rise also shows an increasing trend. In addition, the optimum concentration of hybrid mixture varies with the initial pressure. The explosion risk of hybrid CH4/coal dust is much higher than that of pure coal dust in all dust concentrations, but it is only higher than that of pure coal dust explosion at high CH4 concentrations. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.