Development of preparation and analysis methods for liquefied refrigerant gas mixture standard material

Dalho Kim, Korea Research Institute of Standards and Science (KR)

Multicomponent refrigerants are being used in increasing amounts to replace single compound refrigerants such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). In commercial production and distribution of multicomponent refrigerant, reliable composition analysis is required for quality control and product certification. For this, development of accurate analytical methods and reference materials are essential. However refrigerant is very volatile and used as liquefied form. Therefore, not only development of analytical methods but also development of accurate liquefied multicomponent refrigerant standard by gravimetric method is not simple technically. We selected R-410a, a mixture of difluoromethane (R-32, HFC) and pentafluoroethane (R-125, HFC), as a study materials because it is used widely in air conditioning applications as an alternative of chlorodifluoromethane (R-22, HCFC) scheduled phase out in accordance with the Montreal Protocol on substances that deplete the ozone layer. In this study, we developed a high pressure syringe pump filling-gravimetric method and an evaporative-precise flow control gas injection analytical method by GC/FID for liquefied refrigerant gas mixture, R-410a. We compared evaporative-precise flow control gas injection method with direct liquid injection method as a result evaporative method that equipped with precise flow control valve showed good repeatability (RSD < 0.5 %, n=3). Six liquefied refrigerant gas mixture were prepared independently in 0.5 ~ 1 L gas cylinders by the high pressure syringe pump filling-gravimetric method. When these six mixtures were compared using developed evaporative-precise flow control gas injection GC/FID, the calculated mass fractions by gravimetrically and the analyzed mass fractions showed relative difference of 0.3 ~ 1.6 %.

Pen Profile

Feb 1990 – to date:  Principal Research Scientist, KRISS

Main Resposibility in KRISS:
Development and dissemination of standards for volatile organic compounds (VOC).

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