| Title | Comparison of Methods for Utilization of Geothermal Brine for Power Production |
|---|---|
| Authors | Marta R. Karlsdottir, Halldor Palsson and Olafur P. Palsson |
| Year | 2010 |
| Conference | World Geothermal Congress |
| Keywords | Geothermal power, single flash, double flash, ORC, bottoming unit, optimization. |
| Abstract | The objective of the study is to compare methods that increase power generation from conventional single flash power plants by utilizing waste heat contained in brine from steam separators. Three different utilization methods are investigated by constructing thermodynamic models of different power cycles and optimizing the specific net power output for each cycle using conditions of hypothetical geothermal areas. The cycles investigated include a conventional double flash cycle, an organic Rankine bottoming cycle in parallel with a single flash cycle using isopentane as a working fluid and a modification of the double flash cycle involving an added recuperator between the geothermal brine and the steam at the high pressure turbine outlet. Also, a model of a single flash power plant is constructed for comparison. The specific net power outputs of the different cycles are compared along with the overall efficiency of the cycles. Finally, an economical analysis is performed to further compare the feasibility of the different cycles using conventional economical analysis to estimate the cost of the final product. The results of the study can be used as a measure of comparison between the different conventional methods of utilizing geothermal energy for electrical power production with respect to the energy content, or the enthalpy, of the geothermal fluid produced from production wells. Also, a new method of utilizing geothermal brine by modifying the double flash cycle is introduced and compared to the conventional cycles. The new method could provide useful results for increased power production compared to the other cycles and also, as a future study, provide a method of better controlling the double flash cycle in case of changes in the fluid characteristics from production wells, which is expected in future operation time of geothermal power plants. |