Separation Method for Cross-Aliased Near-IR Absorption Lines of C2H4: a Coal Spontaneous Combustion Marker

Abstract

To tackle the cross-interference problem between CH₄ and C₂H₄ and the aliasing interference problem of C₂H₄ itself, on the basis of the sparse decomposition theory, multiple Lorentz function-based methods were proposed for separating the cross-aliasing interference of near-infrared (IR) C₂H₄ absorption lines. A quadruple Lorentz function-based separation model describing the absorption coefficient of C₂H₄ is developed, with which the absorption lines of background gas and to-be-measured C₂H₄ were separated from the absorption lines of mixed gas, thereby effectively separating the absorption line of C₂H₄ and accurately measuring its concentration. The results show that the maximum errors of C₂H₄ and CH₄ gasometrical analyses are 5.3×10⁻⁶/201.7×10⁻⁶ and 57×10⁻⁶/5000×10⁻⁶, respectively. The proposed method effectively eliminates the errors caused by cross-aliasing interference of C₂H₄ absorption lines in the near-IR bands and improves the detection accuracy of the TDLAS gas detection system. The findings of this study provide a feasible solution to the cross-aliasing interference problem of IR absorption lines.