Experimental Study on Effects of Moisture on in Relation to Coal Oxidation and Spontaneous Combustion Characteristics of Mengba Coal at High Temperature Environments

Mengba coal is mined at a very high temperature and high humidity environment. Normally, the underground temperature is over 40 degrees C, and there are a large amount of water flows out from coal seams. To study the effects of water inflow on the characteristics of coal spontaneously combusted at 40 degrees C, the temperature-programmed experiments were carried out. Five different percentages of water content, which were 3.56%, 5.51%, 7.24%, 9.82% and 11.21%, were tested. Experimental results indicates that the coal samples with 9.82% and 7.24% percentages of moisture content could heat up to 40 degrees C fast, and continue to reach to 43 degrees C due to self-heating at the calorstat. On the basis of the temperature-programmed experiments, it was found that oxygen consumption rate, CO gas generation rate, and exothermic intensity coal samples with different percentages of the moisture content behave similar before the temperature less than 100 degrees C. The oxygen consumption rate, CO gas generation rate, and exothermic intensity of coal samples from high to low was in the order of 9.82%, 7.4%, 5.51%, 2,21%, 11.21%, and 3.56% when the temperature was over 100 degrees C. This finding confirmed that the moisture could involve into the complexing reaction of peroxides during low-temperature oxidation process of coal. The experimental results also indicates that the coal samples with 9.82% and 7.24% moisture content is easily inclined to spontaneous combustion and the indicator of the coal spontaneous combustion varies with the content of the moisture.