作者：胡彪¹, 郭志明², 徐开群³, 谭中柱¹, 何帅¹

作者单位：1. 湖南省计量检测研究院，湖南 长沙 410014;
2. 湖南大学，湖南 长沙 410082;
3. 长沙开元仪器有限公司，湖南 长沙 410100

关键词：热导检测器;灵敏度;热平衡;检出限

摘要：

根据热导检测器的工作原理，分析影响其灵敏度的主要因素，并建立检测器的热平衡模型，可指导优化其性能设计。通过采用四壁直通式流通结构，选用10 kΩ NTC热敏电阻作为热敏元件，设计稳定的恒流电源、高精度控温电路和信号处理电路，研制出高灵敏度的煤炭元素分析仪用热导检测器。经测试，检测器基线噪声为1.5 μV，30 min内的基线漂移为8 μV，灵敏度为12288 mV·mL/mg，碳元素检出限为28.4 μg/g，氢元素检出限为28.8 μg/g，氮元素检出限为11.3 μg/g，满足高通量煤炭元素分析仪多组分联测需求。

Research on high sensitivity thermal conductivity detector in coal elemental analyzer
HU Biao¹, GUO Zhiming², XU Kaiqun³, TAN Zhongzhu¹, HE Shuai¹
1. Hunan Institute of Metrology and Test, Changsha 410014, China;
2. Hunan University, Changsha 410082, China;
3. Kaiyuan Instruments, Changsha 410100, China
Abstract: According to the working principle of the thermal conductivity detector, the main factors affecting the sensitivity of the thermal conductivity detector are analyzed, and a thermal balance model to describe the performance of the thermal conductivity cell is established, which can guide the optimization of its performance design. By adopting a four-wall straight-through flow structure, selecting a 10 kΩ NTC thermistor as the thermal element, designing a stable constant current power supply, a high-precision temperature control circuit and a signal processing circuit, developing a highly sensitive thermal conductivity detector used in the coal element analyzer. After testing, the detector baseline noise is 1.5 μV, the baseline drift within 30 minutes is 8 μV, the sensitivity is 12288 mV·mL/mg, and the detection limit of carbon is 28.4 μg/g, the detection limit of hydrogen is 28.8 μg/g, the detection limit of nitrogen is 11.3 μg/g, which meets the multi-component combined measurement requirements of high-throughput coal element analyzers.
Keywords: thermal conductivity detector;sensitivity;thermal balance;detection limit
2022, 48(11):120-125,137  收稿日期: 2021-08-18;收到修改稿日期: 2021-11-09
基金项目: 国家重点研发计划（2018YFF01014005）；湖南省市场监管局科技项目（2021KJJH64）
作者简介: 胡彪（1983-），男，湖南宁乡市人，高级工程师，主要从事能源分析仪和热工计量技术研究
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