Liquefaction of natural gas and exergy analysis

Energy analysis method, entropy analysis method and availability analysis method are the tools used for thermodynamic system analysis. The objective of this study is to explain the liquefaction of natural gas and to show the importance of availability analysis method in liquefaction systems. Like for all insulation prosesses, the most important aim is to increase the efficiency of compressors. To increase the efficiency, isolation can be done or the compressors isoentropic efficiency can be increased related to its design criteria. On the other hand, calculating the irreversibilities in the cycle, and taking the necessary measures to reduce the irreversibility rate in the cycle are more effective for increasing the cycle efficiency. In this study the first and second law of thermodynamics were given and some formulas were described. Then liquefaction methods and the comparison methods for them were described. In this study three of these methods were especially described. These are Linde, Claude and Cascase methods. After describing these methods some reference points were chosen and according to these points the other points were found. And at each point the exergy was also calculated. With these results, all these three methods were compared by the comparison methods that were indicated before. And as a result the second law efficiency was calculated. Key Words: Natural Gas, liquefaction, LNG, Exergy, Second Law Efficiency