عنوان مقاله [English]
After compressing and increasing the pressure of natural gas in compress station, it has high exergy pressure. The pressure of natural gas is decreased in reduction station by regulators, but this issue can waste exergy. Since energy resources are restricted and its price is increasing in one hand, the exergy analysis method of thermodynamic issue is brought out with economical issues on the other hand, therefore the exergy analysis method is considered as significant issue. This article addresses exergy analysis with using the governing thermodynamic equations and considering natural gas deviation from ideal state and the exergy analysis of natural gas in reduction city gate station (the station No. 1 of Semnan is considered as a case study). The amount of exergy waste is calculated and guideline for its reduction is presented. In accordance with carried out calculations, on the average 198.7 MW of exergy is wasted in the Pressure Reduction Station No.1 located in Semnan in the year of 2009, we can prevent to waste the 231.98KW of exergy with regulating the appropriate temperature of heater when it is working and the studied station.