Energy efficiency and thermochemistry of sulfur-containing coal gangue, a coal-based solid waste

Abstract

Under typical conditions, sulfur-containing CG demonstrates a greater propensity for spontaneous combustion compared to standard CG. The influence of sulfur components on the oxidation and spontaneous combustion processes is still ambiguous, significantly affecting the management of spontaneous combustion in CG and environmental conservation. This study uses TG-DSC-MS technologies to categorize the oxidation and pyrolysis processes of CG into four distinct stages and examine the emission patterns of indicator gases. Employing in situ diffuse reflectance The dynamic evolution of functional groups during the oxidation and pyrolysis processes of CG is examined using Fourier transform infrared spectroscopy (in-situ DRIFTS). The activation energy of the reaction was determined utilizing the FWO, KAS, and Achar methods, elucidating the reaction pathways and thermodynamic properties of the breakdown of aliphatic hydrocarbons and oxygen-containing functional groups by sulfur-containing compounds such as pyrite. The findings demonstrate that CG possesses characteristics akin to those of low-rank coal. The breakdown of oxygen-containing functional groups, such as hydroxyl and carbonyl groups, is closely linked to the release of gases like CO₂ and SO₂, explaining how self-ignition warning gases are produced. Thermal degradation of sulphur-containing CG releases many hazardous gases. Studying sulphur migration patterns and gas release during the thermal decomposition stage provides a theoretical basis for environmental protection and sulphur gas emission reduction.