基于可调谐半导体激光吸收光谱技术(TDLAS),引入模糊自适应比例积分微分循环控制算法实现腔体内部温度和压力的精确控制,选取1658 nm附近的双近红外吸收谱线对实现 12CH4和 13CH4气体稳定碳同位素的同时测量。通过对来自煤矿井下不同煤层和位置的瓦斯气样进行分析可知,其浓度范围为0.94%~83.91%,所得同位素丰度在-66.75‰到-48.32‰之间。该方法可以很好地区分煤层瓦斯气体来源,并且可以依据同位素丰度值对瓦斯的成因类型进行判断。该技术可为后续开展矿井瓦斯运移通道研究、瓦斯灾源预警、煤层气研究及大气环境研究等提供支持。

Based on the tunable diode laser absorption spectroscopy (TDLAS), a fuzzy adaptive proportional-integral-differential cycle control algorithm is introduced to achieve precise control of temperature and pressure inside the cavity, and the simultaneous measurement of stable carbon isotopes in ¹²CH₄ and ¹³CH₄ gases has been achieved by utilizing TDLAS via monitoring the near infrared absorption line at 1658 nm. Examination of gas samples from various coal seams and differing locations in coal mines allows for differentiation of gas source and elucidation of the origin type of the gas based on the observed isotope abundance. The detectable concentration range for the methodology is 0.94%-83.91%, and the isotopic abundance varies from -66.75‰ to -48.32‰. This technology lays the foundation for distinguishing coal seam gas sources and judging the gas types according to the isotopic abundance, and provides a valuable tool for areas such as gas transport channel in mine, early warning for gas disaster source, coalbed methane research, and environmental atmospheric studies.