Effect of Moisture Content on Spontaneous Combustion Characteristics of Bituminous Coal in Wuda Coal Field

Abstract

To investigate the influence of water content on coal combustion characteristics, bituminous coal was collected as the research target from the Wusitai Coal Mine. The combustion characteristic parameters of coal samples with various water contents were measured by cone calorimeter, and the combustion efficiency of coal samples was analyzed. The spontaneous combustion characteristics of samples are significantly affected by moisture within coal. As the rise of moisture content, the ignition time of bituminous coal is firstly reduced and then it is enhanced. The coal sample with moisture content of 10.36% has the fastest ignition. The total smoke discharge, the peak heat release rate and the flue gas generation rate of bituminous coal samples are firstly decreased, then increased and finally reduced with the increase of water content. In the later stage of combustion, the CO generation rate is the smallest for the bituminous sample with water content of 6.59%, while it is the largest for the sample with 18.78% content of moisture. Large moisture content makes the coal sample incomplete combustion, which can improve the CO production rate. The combustion efficiency of bituminous coal can be improved by the appropriate moisture content. It was found that the total CO generation rate, smoke release rate and the ignition time are effectively reduced, after setting the moisture content of 6.59–10.36% of the coal. As a result, both the combustion efficiency and heat release rate are improved.