Supercritical carbon dioxide geothermal power generation system and method

Abstract

The invention discloses a supercritical carbon dioxide geothermal power generation system and method. The system comprises a flashing loop valve, a flashing tank, a supercritical carbon dioxide loop valve, a turbine, an electric generator, a precooler, a compressor, an after-cooler, a fossil fuel power plant exhaust gas carbon dioxide collecting and treating device, an injection well, an output well and the like. The system can realize the purpose of developing geothermal resources and also can realize geological sequestration of carbon dioxide in exhaust gas of a fossil fuel power plant, so that the situation that the thermal power plant and geothermal exploitation are combined to generate electricity so as to realize zero emission of carbon dioxide becomes possible.

Description

technical field [0001] The invention belongs to the technical field of geothermal resource development and carbon dioxide sequestration, and in particular relates to a supercritical carbon dioxide geothermal power generation system and a power generation method. Background technique [0002] Geothermal energy refers to the thermal energy inside the earth that can be exploited and utilized under the technically and economically permissible conditions in the current and foreseeable future, including thermal fluids in crustal rocks and their associated useful components. It is generally believed that geothermal energy mainly comes from two parts, one is the heat generated by molten rock magma, and the other is the heat generated by the decay of radioactive elements in the earth's crust. [0003] As an important type of geothermal resources, hot dry rock has gradually become a research focus of scholars at home and abroad. Hot dry rock is buried deep (3000-10000m), high tempera...

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Problems solved by technology

However, the practical application shows that there are many negative problems in using water as the heat-carrying medium: (1) the leakage of water injected into the ground is serious, and the leakage rate is about 10-70%, which causes a large increase in the consumption of water resources; (2) When the heat source temperature is higher than the critical temperature of water, minerals will be dissolved and precipitated due to the thermochemical interaction between water and rock formations, which will cause a short circuit or blockage between the injection well and the production well, which will affect the heat-carrying working medium endothermic process

[0005] However, according to investigations, few supercritical carbon dioxide geothermal power generation technologies that have been disclosed at the same time are coupled with the capture and storage of carbon dioxide in the flue gas of fossil fuel power plants, and in the disclosed supercritical carbon dioxide geothermal power generation technologies, there are still the following problems that cannot be solved : (1) The proposed supercritical carbon dioxide geothermal power generation system is aimed at supercritical carbon dioxide as the heat-carrying medium. For the actual application of geothermal power generation, the initial heat-carrying medium is a mixture of supercritical carbon dioxide and water vapor. Applicable; (2) The proposed supercritical carbon dioxide geothermal power generation system cannot make full use of the unique physical characteristics of supercritical carbon dioxide as a heat-carrying medium itself, such as compression near the critical point, which can greatly reduce the power consumption of the compressor; The critical carbon dioxide absorbs heat in the geothermal reservoir, and the pressure will increase significantly, so that the transmission power equipment in the development and utilization of geothermal energy can be canceled

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