Temperature-Programmed Oxidation Experiments on Typical Bituminous Coal Under Inert Conditions

Abstract

In this study, an experimental investigation was presented on the oxidation behaviors of bituminous coal for different inert gases (N2 and CO2) at different concentrations (oxygen concentration indexes 21%, 18.4%, 15.8%, and 13.1%) using a temperature-programmed experimental device. The purpose of this research was to examine the oxidation patterns of bituminous coal under different inert conditions. The results showed that (1) the oxidative heating of the coal underwent two stages: an initial slow heating stage and a fast heating stage. The injection of both inert gases would result in a delay in the crossing point temperature (CPT) of the coal, but injection of N2 resulted in greater delays in the CPT of the coal; (2) the injection of both N2 and CO2 inhibited the concentrations of CO and alkane/olefin gases produced from the oxidative heating of the coal, with CO2 displaying higher inhibition efficiencies than that of N2. (3) under non-inerting environment, the C2H4 and C2H6 generation temperatures were 110°C and 100°C. Under inerting environment, when N2 was injected, the higher the N2 concentration, the higher the initial C2H4 and C2H6 generation temperatures; when CO2 was injected, the higher the CO2 concentration, the lower the initial C2H4 and C2H6 generation temperatures. The above research results can be used to predict the spontaneous combustion of residual coal in an inert environment and prevent fires.

Explosive Characteristics and Kinetic Mechanism of Methane–Air Mixtures under High-Temperature Conditions

“…Ambient conditions have important influences on the explosive characteristics of combustible gas. Therein, the ambient pressure and ambient temperature exert the greatest influences. − In China, high-temperature condition is inevitable in coal mines with the increase in mining depth and spontaneous ignition of coal seams. , In the utilization of low-concentration oxygen-containing gas, processes including methane extraction by pressure swing adsorption, gas deoxygenation and concentration, and low-concentration gas regenerative oxidation also encounter high-temperature conditions, so the temperature rise poses a severe challenge for controlling gas explosion. Therefore, studying explosive characteristics of methane under high-temperature conditions can provide an important theoretical basis for the prevention of gas explosion accidents, design of bearing pressure devices, and explosion venting design.…”