Optimising Net Turbine Power for Gas Content of Geothermal Steam

Abstract

The gas content of geothermal steam varies Over a wide range and consists carbon dioxide. For equal weights, this gas is half as effective as steam when expanded through a turbine for Hence, its elimination from the entry steam - by chemical or other means - can reduce the electric energy generated by turbines which discharge to the atmosphere. But for the more efficient condensing turbine (with vacuum exhaust), the reverse is true ; this is because of the large amount of power required to pump the gases fran the ccndenser. If the gas cannot be removed to increase net power, then optimising leads to a specific condenser pressure required for any particular gas concentration in the steam. Graphed results present the relationship and permit ease of selection of the condenser vacuum pressure.