Background & aim :The Compressed Natural Gas(CNG)emphasize as clean fuel in reducing contaminating, limitation in providing air, oil resources and subsequently less expenses, preparation and utilization of Natural Gas regarding to gasoline and oil. Through this recent years, natural gas cause increasing the station development to it in the country. The study of statistics interruption fuel station delivery of CNG, shows up important breaking of quick over going bad interruption , it is only some of systems equipments are concerned , that is why these should be a manner of reliability to make the profit .To recognize the elements crisis of a fuel delivery station of CNG it is very important ,so this study focused on reliability assessment of CNG station by Reliability Blocks Diagram method.
Method: the recent study is as a case study one to reliability assessment in a CNG station in Shahriyar city in 1391.in this study with due attention to estimated failure rate and reliability in each equipment the portion failing in each equipping at whole system be specified. during the reliability of estimating ,after recognizing and studying the system and process drawing ,documentation and report system equipment decay ,using the knowledge of experts and technical specialists, using respective formula and analyzing estimated calculation , critical system element being assigned.
Finding: the result showed that PLC(Programmed Logic Control) equipments with reliability 0.5 , Compressor with reliability 0.846 and Check Valve with reliability 0.91 are critical elements.
Conclusion: this study recommended to be done action for increase of reliability by the use of excess components (redundancy) for critical equipments then proposed offers should study the case from an economic point of view to be settle.
Keywords: Compressed Natural Gas Station, reliability block diagram, redundancy, Failure
