离子色谱法测定氢燃料电池汽车用氢气中卤化物

Determination of halides in hydrogen for hydrogen fuel cell vehicles by ion chromatography

关键词:  燃料电池汽车  氢气  卤化物  离子色谱法  氯化物 

Key words:  fuel cell vehicle  hydrogen  halide  ion chromatography  chloride

摘要:

目的 为提升氢燃料电池汽车(FCV)用氢气质量,解决氢气中痕量卤化物杂质难以准确定量的技术问题。方法 以“碱液+还原剂”作为吸收液,建立了离子色谱法测定FCV用氢气中卤化物的分析方法。当有氯气杂质存在时,单独的水或碱液作为吸收液均无法实现氯气的完全吸收。还原剂硫代硫酸根在碱性条件下可以将次氯酸根全部还原成氯离子,提高氯气的吸收效率。结果 以“NaOH+S₂O2-₃”作为吸收液,氯气的吸收效率可达91.0%,氯化物混合物的吸收效率均为92.6%~115.9%。低含量的氯化氢和氯气样品的吸收效率在80.0%以上,两次平行试验测定值的相对偏差均小于10%。氯化氢和氯气检出限分别为0.014 μmol/mol和0.007 μmol/mol。结论 该方法可以满足FCV用氢气中卤化物的检测要求,所采集的4种不同来源的FCV用氢气中卤化物杂质均低于GB/T 37244—2018《质子交换膜燃料电池汽车用燃料 氢气》的限值。 

Abstract:

Objective The study aims to improve the quality of hydrogen for hydrogen fuel cell vehicles (FCV), as well as solve the technical problem that trace halide impurities in hydrogen is difficult to be accurately quantified. Methods A method for the determination of halides in hydrogen for FCV by ion chromatography was developed using "lye + reducing agent" as absorption solution. When chlorine impurities exist, neither water nor lye as absorbent solution could fully absorb chlorine gas. The reducing agent thiosulfate could completely reduce hypochlorite to chloride ion under alkaline condition and improve the absorption efficiency of chlorine gas. Results With "NaOH + S₂O2-₃" as the absorption solution, the absorption efficiency of chlorine gas reached 91.0%, and the absorption efficiencies of chloride mixture were 92.6%-115.9%. The absorption efficiencies of low concentration hydrogen chloride and chlorine gas samples were more than 80.0%, and the relative deviations of the two parallel tests values were less than 10%. The detection limits of hydrogen chloride and chlorine were 0.014 μmol/mol and 0.007 μmol/mol, respectively. Conclusion sThe established method meets the requirements of halide detection in FCV. All of the halide impurities in hydrogen for FCV collected from four different sources were lower than the limit value of GB/T 37244-2018 Fuel specification for proton exchange membrane fuel cell vehicles—Hydrogen.