Improvement of a double flash cycle using a heat exchanger with liquid cooling and liquid splitting technology for a geothermal power plant

A heat exchanger was integrated to increase the efficiency of a geothermal double flash cycle and decrease the liquid content at a low-pressure turbine outlet. The liquid cooling (LC) and liquid splitting technologies have three different configurations: i.) steam superheating (SH), ii.) steam reheating (RH) and iii.) mixture heating (MH) was implemented. An exergoeconomic analysis was applied to the systems and analyzed using geothermal power plant operation parameters. An increase in the net power of the double flash cycle of 418.6 kW was achieved with LC-SH configuration, 5008.6 kW with LC-RH, 5248.6 kW with LC-MH, 3758.61 kW with LS-RH and 3958.61 with LS-MH. The power of the low-pressure turbine also increased compared to the double flash design in a 0.5236% (SH), 5.48%(RH), and 5.72%(MH), and the produced electricity cost were 5.9963 $USD/GJ, 5.9976 $USD/GJ, 6.0089 $USD/GJ, 6.0086 $USD/GJ, 5.9336 $USD/GJ, 5.9482 $USD/GJ and 5.9481 $USD/GJ for the double flash, DF-LC-SH, DF-LC-RH, DF-LC-MH, DF-LS-SH, DF-LS-RH, and DF-LS-MH designs, respectively. The DF-LS-SH design is the most feasible because the cost of electricity produced is reduced while the steam quality of the low-pressure turbine and the net power of the geothermal plant increases. •Six modifications to a double flash cycle were analyzed from an exergoeconomic point of view.•The design of liquid splitting and superheating reduced the exergy cost to 5.9336 $ USD/GJ compared to the double-flash base case.•The liquid cooling technology with mixture heating improved the net power by 5331.61 kW.•The liquid content at the outlet of the low-pressure turbine was reduced by 5.54%.