Many chemicals, such as Methanol synthesis reactor productions, are produced under high pressure and  temperature. The reactor operates at 80 (bar) pressure and 250 ( C) temperature. In a conventional process, high exergy in reactor outlet is not used. The high operating   pressure of the reactor outlet can be exploited to produce electricity by integration of a turbo expander. Moreover, increasing in production would be the other result of this method .In this research, simulation has been done by applying HYSYS (Ver. 2006) and the results are in consistent with the outcomes of modeling technique .Economic analysis shows that we can generate about 6.5 ( MW) electricity and return of investment is less than 2 years.