Experimental Study on Suppression of Coal Dust Combustion by Inert Medium

The study aims to analyze the effect of inert medium on coal combustion and effectively prevent spontaneous combustion of coal dust. Thermal analyzer and gas chromatograph were used to measure changes of quality and concentration of CO and CO2. The inert mediums are H2O, NH4H2PO4 and CaCO3. Tests of single inert medium, NH4H2PO4 and CaCO3 with different proportions and particle sizes on the inhibition of combustion were conducted. The results show that the inhibition effect of NH4H2PO4 and CaCO3 mixture is better than that of H2O and CaCO3 but weaker than NH4H2PO4 alone. The effect of inert medium in the process of instantaneous explosion and slow oxidation is not identical and there is no synergistic suppression effect on coal dust combustion. With the decrease of the size of NH4H2PO4 , the inhibition performance is enhanced.