氦气中氘、氧和氮气的气相色谱分析

DETERMINATION OF DEUTERIUM, OXYGEN AND NITROGEN IN HELIUM BY GAS CHROMATOGRAPHY (GC)

反应堆在运行中由于空气的漏入及慢化剂重水辐解产物的生成,复盖气体He中会含有微量D2,O2,N2,CH4,CO和CO2等杂质。为确保反应堆正常运行需对He气中杂质进行监测。国外多用气相色谱法做常规分析,但需采用双柱甚至三柱切换,操作比较麻烦。本工作采用5A分子筛单柱分离-程序升温法,以He为载气将D2,O2,N2,CH4,CO和CO2六种杂质气体完全分离,并用标准曲线法对其中D2,O2和N2作出定量分析。

The paper describes the chromatographic separation of D_2 ,O_2 ,N_2 ,CH_4 ,CO and CO_2 in He and the quantitative analysis method of D_2, O_2 and N_2 by GC. A 5A molecular sieve column and temperature program are used. The components of D_2,O_2, N_2 ,CH_4 ,CO and CO_2 in He can well be separated. He is used as carrier gas and TCD as detector, the respective sensitivities of D_2,O_2 and N_2 are measured. The sensitivity of N_2 is highest in these components and the relative sensitivities of D_2 and O_2 compared with N_2 are 0. 1 and 0.9, respectively. When the pressure of injected sample is 0.1MPa and the volume is 0. 5ml, the detection limit of D_2 is 0.004% ( n/n ). The relative standard deviations are 1% for sample larger than 3%( n/n ) component and 10% for 0. 05%～1%( n/n ) component. This method can be used to monitor these impurities in helium blanket gas of a nuclear reactor.