用数学解析法校正热导法测氢时共存气体的干扰

Mathematic Analysis Correction for Interference of Coexisting Components in on-Line H_2 Thermal Conductivity Measurement

用热导法在线测定工艺气体中的氢含量,灵敏度高、简便廉价,但容易受到共存组分的影响,尤其是共存组分含量较高且变化较大时,其干扰更加严重。本研究采用数学解析法对CO和CO2两种气体的干扰作用进行了校正,在不延长分析时间的情况下,提高了测氢的精度。模拟实验结果表明:对于氢的体积分数为0～20%且含有大量CO(0～90%)、CO2(0～50%)和N2(平衡气)的混合气体,校正后的测量值的绝对误差在±0 5%之间;校正过程的耗时与系统响应时间相比完全可以忽略。

Thermal conductivity analysis is a sensitive, simple, convenient and inexpensive method for online analysis of H2 in industrial processes. However, this method is apt to be affected by the coexisting components in gas samples, especially by those of high content or rapid change with the process. A mathematic analysis method can be used to correct the interference of CO and CO2. It has been proved that this correction method improves the analysis precision and at the same time does not bring any delay to analysis process. For analysis of the mixtures consisting of H2 (0-20 %, volume fraction), CO (0-100 %, volume fraction), CO2 (0-50 %, volume fraction) and N2 (balance), the error of the H2 could be controlled less than ±05 %. The simulation experiment showed that the precision of the analysis with correction is satisfactory and the time for correction is so short compared with the response time of the analysis system thus could be completely neglected.