ali rzaei - nationnal iranian gas company zanjan gas company
roghayeh raoufizadeh

gas transmission system in iran includes three high pressure trnsit piprlines and gas pressure enhanced systems . The natural gas is transported through transit pipelines with maximum pressure 1050 psi and minimum pressure 350psi to city gate stationsCGS, after pressure reduction to 250 psi using gas supply network pipelines or basic grid BG is supplied to town houndary systems TBS , the gas at passing into this stations after reduction with pressure 60 psi is transferd to gas distribution piplines that is reducted to minimum pressure 1/4 psi by servic regular. throttle - valve or joule -thompson valve for customers , in during this stages does not make use of the mechanical energy avilable in the gas this paper calculate and estimate the energy that can be extracted from pressure reduction equipment using an expansion turbine which is replacemented in the throttle valve place and then coupled to an electrical generator for convertion the mechanical work to electrical energy , produced power can be supplied to the electricy distribution network and was showed that the electrical power generated from redution pressure is very much that can illuminate around 7000 lamps.

city gate station , expansion turbine ,throuttle valve , the first rule of thermodynamic.