基于小样本的煤层自然发火烷烃气体的光谱分析

Spectral analysis of alkane gases of coal spontaneous combustion with a small quantity sample

针对煤层自然发火标志气体中烷烃气体吸收光谱交叠严重、定量分析时需要大量样本进行标定的问题,对甲烷、乙烷、丙烷、异丁烷、正丁烷5种气体吸收光谱谱图进行研究,分析了谱线与气体浓度的非线性特性,得出吸收光谱部分谱线具有良好的线性度。采用改进的Tikhonov正则化方法进行了特征变量的提取,建立了分析模型,给出了5种烷烃的测试结果。采用Tensor 27光谱仪在光程为10 cm,扫描次数为8,光谱分辨率为1 cm-1情况下,只需20余组样本即可实现这些气体的高准确度在线分析,所有气体的分辨率优于2×10-6,满足煤层自然发火气体检测要求。

The alkane gases absorption spectra of coal spontaneous combustion index gases are seriously overlapped, and the quantitative analysis of absorption spectra requires a large amount of samples for calibration. Due to these issues,the absorption spectrogram of methane, ethane, propane, isobutene and n-butane were investigated, and the nonlinear characteristic between spectral line and gas concentration was analyzed. The results show that the partial spectral line of absorption spectra possesses favorable degree of linearity. The characteristic variable was extracted using improved Tikhonov regularization method. The test results of the five kinds of alkanes were given by establishing analysis model. More than 20 groups of samples achieved the gases high accuracy in online analysis using the Tensor 27 spectrograph whose optical distance is 10 cm,the number of scanning times are eight times, spectral resolution is 1 cm^-1. The resolution ratio of all gases is better than 2 × 10^-6. The gas resolution ratio meets the test requirements of coal spontaneous combustion.