Experimental study on combustion and extinguishing of secondary oxidation coal

Abstract

The spontaneous combustion of coal in the goaf, which belongs to secondary oxidation coal seriously threatens the safe production of coal mines.Nitrogen can be used as a fire extinguishing agent to inhibit spontaneous combustion of residual coal.In order to study the effect of nitrogen on secondary oxidation coal, thermogravimetric analysis and temperature programmed system are used to carry out experiments on and analysis of heating process and extinguishing process.During the heating process, as the concentration of nitrogen increased, the characteristic temperatures increased, and nitrogen inhibited the combustion of secondary oxidation coal.In the process of cooling and extinguishing fire, the temperature and indicator gas CO concentration were used as monitoring parameters to test the fire extinguishing effect.The analysis shows that when a mixture of nitrogen and air with the ratio of 50%/50%, was introduced into the secondary oxidation coal programmed to 400℃, the time was reduced by 38.0% compared with the natural temperature drop, also the time for CO concentration to drop to 0 was shortened by 42.1%.The higher the nitrogen concentration, the shorter the fire-extinguishing time of the secondary oxidation coal, and the less the product produced, the better the fire-extinguishing effect.

Keywords

• secondary oxidation coal
• spontaneous combustion
• nitrogen
• extinguishment