The optimization and experimental research of optical interference methane concentration measurement model

To enhance the accuracy and applicability of optical interference methane concentration analyzers,particularly in the low-oxygen environments of underground coal mines,this study addresses the common issues of unstable readings and large measurement deviations. Building on the traditional optical interference methane concentration model,we incorporated the effects of environmental temperature,air pressure,and the varying concentrations of O₂ and N₂ in methane-containing gas mixtures. Based on these considerations,we developed and constructed an optimized measurement model in which the refractive index was treated as a variable rather than a fixed parameter. To validate the improved model, we conducted comparative laboratory experiments using standard gas mixtures. We prepared nine different mixtures containing O₂, CH₄, CO₂, and N₂, varying O₂ concentrations at 18. 00%,19. 00%,and 20. 00%,and CH₄ concentrations at 0. 50%,1. 00%,and 1. 50%. The results showed that the methane concentrations calculated by the optimized model closely matched the laboratory standard values and were unaffected by changes in O₂ concentration. The maximum error did not exceed 0. 03%, demonstrating significantly higher accuracy than traditional optical interference analyzers. In summary, the optimized optical interference methane concentration measurement model not only improves accuracy but also overcomes the limitations of traditional analyzers,which are sensitive to environmental O 2 levels. This makes the new model more suitable for accurately measuring methane concentrations in the complex environments of underground coal mines.