Geothermal liquid water at 200°C is extracted from a geothermal well at a rate of 100 kg/s. This water is flashed to a pressure of 500 kPa in the flash chamber of a single-flash geothermal power plant. The condenser is maintained at a pressure of 10 kPa. The quality of the steam at the turbine exit is 83 percent.

(a) What is the mass flow rate of water vapor at the turbine inlet?

(b) Determine the power output from the turbine and the thermal efficiency of the plant.

(c) Assume this single-flash plant is retrofitted to operate as a double-flash plant. The first and second flash pressures are selected as 500 kPa and 150 kPa, respectively. What are the power output and thermal efficiency of this double-flash plant? Other parameters remain the same.

 

Steam Steam turbine turbine Separator 10 kPa Separator Condenser Condenser 500 kPa Separator II Flash chamber Flash chamber Flash chamber 200C 100 kg/s Production Production well Reinjection well Reinjection well well to-1