Abstract In this paper, as a promising technology, the binary flashing cycle (BFC) is proposed for enhanced geothermal systems (EGS) exploitation. The detailed thermo-economic model is developed. With the thermal efficiency, net power output, total investment cost and levelized energy cost (LEC) as evaluation criteria, the flowsheet modeling and thermo-economic analysis are conducted. It is revealed that larger geothermal well depth and geothermal brine flow rate are in favor for improving system thermal performance. However, it is not always beneficial for the economic performance. There exist the optimal depth (3300 m) and geothermal brine flow rate (57 kg/s), at which the LEC obtains the minimum (0.329 USD/kWh) and (0.328 USD/kWh), respectively. For an economic EGS operation, the geothermal brine flow rate should be no less than 50 kg/s. The influences of operating parameters, including generation temperature, dryness degree at the vapor generator outlet and flashing temperature, on the evaluation criteria are also discussed. To achieve better economic benefits, the generation temperature should be less than 110 °C and the dryness should be larger than 0.2. With the flashing temperature 72−82 °C, the EGS-BFC yields excellent thermodynamic and economic performance. The present investigation will be helpful for the geothermal well construction, resource mining and generation system operating parameters design.

中文翻译：

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强化地热系统二元闪蒸循环的热经济研究

摘要 在本文中，作为一种有前途的技术，二元闪蒸循环（BFC）被提出用于增强地热系统（EGS）的开发。开发了详细的热经济模型。以热效率、净输出功率、总投资成本和平准化能源成本（LEC）为评价标准，进行了流程建模和热经济分析。结果表明，较大的地热井深度和地热卤水流速有利于提高系统热性能。然而，它并不总是有利于经济表现。存在最佳深度 (3300 m) 和地热卤水流速 (57 kg/s)，LEC 分别在这两个位置获得最小值 (0.329 USD/kWh) 和 (0.328 USD/kWh)。对于经济的 EGS 操作，地热卤水流速应不低于 50 kg/s。还讨论了发生温度、蒸汽发生器出口干燥度和闪蒸温度等操作参数对评价标准的影响。为获得较好的经济效益，发电温度应小于110℃，干燥度应大于0.2。EGS-BFC 的闪蒸温度为 72−82 °C，具有出色的热力学和经济性能。本研究对地热井建设、资源开采和发电系统运行参数设计有一定的帮助。生成温度应小于110°C，干燥度应大于0.2。EGS-BFC 的闪蒸温度为 72−82 °C，具有出色的热力学和经济性能。本研究对地热井建设、资源开采和发电系统运行参数设计有一定的帮助。生成温度应小于110°C，干燥度应大于0.2。EGS-BFC 的闪蒸温度为 72−82 °C，具有出色的热力学和经济性能。本研究对地热井建设、资源开采和发电系统运行参数设计有一定的帮助。