In this research a performance of TurboExpander and Joule- Thomson valve will be compared in a proposed system developed in order to recover flare gas in oil fields outstations which not connected to any gas plant and burns continually the entire associated gases in the flare, and reuses the mentioned gases in central process facilities as a fuel in gas turbines which use diesel (as they have dual system gas-diesel), while the associated gases in related outstations are burned.