The influence of silicification on coal low-temperature oxidation characteristic parameters

Abstract

In order to study the effect of silicification on low temperature oxidation characteristics of coal, scanning electron microscopy(SEM) was used to observe the difference of pore structure between silicified coal and non-silicified coal; the temperature programmed test system of spontaneous combustion of coal was used to test the characteristics of low temperature oxidation of two coal samples at different temperatures and the variation rule of indicator gas. On this basis, the oxygen consumption rate at different temperatures in the process of low temperature oxidation was analyzed. The results show that silicification enlarges the pores and increases the specific surface area of coal, on the one hand, it is beneficial to the occurrence of gas in coal, on the other hand, the composite reaction between coal and oxygen is more sufficient, and the silicified coal is easier to oxidize and spontaneous combustion; the volume fraction of the marker gas generated in the oxidation process of silicified coal is always higher than that of non-silicified coal, and when the temperature rises to 110 ℃, the difference in the volume fraction of the gas products of the two coal samples gradually becomes larger, which may be because silicification causes physical and chemical changes in coal body and its molecular structure, leading to oxidation cracking of silicified coal more easily; the rate of oxygen consumption and CO formation of silicified coal is always higher than that of non-silicified coal, indicating that silicification enhances the low temperature oxidation characteristics of coal.

Keywords

• silicified coal
• oxidation properties
• temperature programming
• spontaneous combustion of coal
• fire warning