Experimental study on the effect of sulfur content on spontaneous combustion characteristics of anthracite

To study the influence of different sulfur contents on the spontaneous combustion characteristics of anthracite, the oxidation processes of five coal samples with different sulfur contents (1.02%, 3.07%, 5.14%, 7.13% and 11.98%) were tested and analyzed using a tube furnace programmed temperature rise experimental system. The variation laws of the volume fractions of related gases with temperature were investigated, and the influence laws of different sulfur contents on the release characteristics of CO and CO2 gases and the spontaneous combustion characteristic temperatures during the low-temperature oxidation of coal were quantitatively analyzed. By calculating the oxygen consumption rates of coal samples with different sulfur contents under various temperature conditions, the variation pattern of oxygen consumption rate with temperature was quantitatively investigated. Using the principles of chemical reaction kinetics, the apparent activation energy of the coal samples under different sulfur contents was calculated, and the variation pattern of the apparent activation energy with sulfur content was quantitatively analyzed. The results show that when the sulfur content remains constant, the release amounts of CO and CO2 gases and the oxygen consumption rate all increase exponentially with the rise in temperature, while the apparent activation energy gradually decreases. Before the critical temperature, the changes in the release amounts of CO and CO2 gases, the oxygen consumption rate, and the apparent activation energy are relatively small, but after the critical temperature, the changes become significant. As the sulfur content increases, the release amounts of CO and CO2 gases and the oxygen consumption rate at each temperature point show a pattern of first increasing and then decreasing. The maximum values are reached at a sulfur content of 5.14%. The auto-ignition characteristic temperature and apparent activation energy show an opposite pattern of change. They reach their minimum values at a sulfur content of 5.14%, at which point the coal sample has the greatest tendency to self-ignite, indicating that the critical value of sulfur content on the self-ignition tendency of anthracite is approximately 5.14%.