CO Migration Characteristics and Catalytic Oxidation Control in the Upper Corner of Shallow-Buried Spontaneous-Combustion-Prone Coal Seams

To address the continuous accumulation of carbon monoxide (CO) in the upper corner of working faces in shallow-buried easily spontaneous combustion coal seams, this study takes the 1113 fully mechanized mining face of Yidong Coal Mine in Shaanxi Province as the engineering background and investigates the CO migration characteristics in the upper corner and catalytic oxidation removal technology. First, a CFD model of gas migration in the goaf was established. The reliability of the model was verified by comparing the simulated oxygen concentration distribution characteristics and the range of the spontaneous combustion “three zones” with field monitoring results. Based on the validated model, the distribution and migration characteristics of CO concentration in the goaf were analyzed, revealing the migration process of CO from the goaf to the return air corner and its accumulation characteristics. Independent field monitoring further confirmed the occurrence of persistent CO accumulation and over-limit concentrations in the upper corner, supporting the engineering significance of the CO migration pathway predicted by the CFD model. To overcome the limitations of traditional prevention measures in removing already-formed CO, catalytic oxidation experiments were conducted to investigate the variation characteristics of gas components during CO oxidation under ambient temperature conditions. The effects of oxygen concentration, CO concentration, and catalyst dosage on CO removal performance were also studied. The results showed that the catalyst could achieve efficient CO oxidation removal and demonstrated high activity for low CO concentrations, with 100 ppm and 200 ppm CO being completely eliminated in laboratory tests. In field applications, the upper corner CO concentration was reduced from 80 to 142 ppm to 0–16 ppm. The research results provide a theoretical basis and technical reference for CO control in the upper corner of shallow-buried easily spontaneous combustion coal seams.