Iman tirooni - Faculty engineering, Ferdowci of mashhad,Mashhad ,Iran
Majid pakizeh - Faculty engineering, Ferdowci of mashhad,Mashhad ,Iran
Morteza sadeghi - Faculty chemical engineering. Isfahan university of technology,Isfahan, Iran
Hemat shirvani - Faculty chemical engineering. Isfahan university of technology,Isfahan, Iran

Natural gas is mainly Contain 70-95 percent methane and in addition to methane Useful compounds such as ethane, propane and butane Out of the well. These gases due to thehigher heating value than methane and The transformations of these gases are produced valuable therefore separation thesecompounds of methane is looking in the industry. Today, membrane operations can be with respect to benefits that a good alternative to the operations old but Its important Membrane selected for the desired operation as for Diversity membranes [1].Dense polymer membrane is used for gasseparation which are divided into two categories Rubber and glass. Solubility in the rubber membrane transport properties are controlled The molecular size is greater than its ability to pass through the membrane is more In this study we have used the rubber membrane and Polyurethane polymer is desired. Polyurethane are the group of polymer that are considered as a membrane in the different separation fields because of their good mechanical, chemical and thermal properties [2-3].