Study on Inhibition of Spontaneous Combustion of Coal by Liquid CO2

Abstract

To study the inerting and cooling characteristics of liquid CO₂ in coal mine, the coal samples before and after liquid CO₂ inerting treatment were analyzed and studied. The results of temperature-programmed oxidation experiment show that the coal sample can inhibit the oxidation of coal to a certain extent after liquid CO₂ inerting. The TG-DSC experiment results show that T1 and T2 of treated coal are higher than those of raw coal, which indicates that the desorption and heat absorption of CO₂ has a more obvious effect on the early stage of coal oxidation at low temperature. The characteristic temperature T3 and T4 of L‑CO₂ coal are lower than that of raw coal, indicating that the oxidation rate of raw coal is faster. The T4 of L-CO₂ coal is higher than that of raw coal. The results showed that L-CO₂ inhibited spontaneous combustion of coal. After the coal sample was treated with liquid CO₂, the apparent activation energy of the coal increased slightly. The heat release of raw coal is 10.78% higher than that of treated coal samples. From the point of view of heat change, it shows that raw coal is more prone to spontaneous combustion. Liquid CO₂ has a good cooling and inerting effect on fire prevention.