Energy conversion system used in intensified geothermal system with CO2 as working medium

Abstract

The invention relates to an energy conversion system used in an intensified geothermal system with CO2 as a working medium. The energy conversion system is characterized by comprising a ultrahigh-voltage CO2 thermal power generation system and an organic rankine thermal power generation system, wherein endothermic CO2 in a geothermal reservoir is taken as the working medium for the ultrahigh-voltage CO2 thermal power generation system, and heat energy is converted into electric energy through turbine expansion working; and a rankine cycle working medium in the organic rankine thermal power generation system exchanges heat with CO2 subjected to working doing, and the heat energy is converted into the electric energy through a rankine cycle. According to the invention, because the ultrahigh-voltage CO2 thermal power generation system and the organic rankine thermal power generation system are combined in use, the conversion efficiency in converting the heat energy into the electric energy is effectively increased; meanwhile, the heat utilization rate of the geothermal system is increased, long-term sequestration of partial CO2 can be realized, and the emission of the CO2 to the atmosphere is reduced. The energy conversion system disclosed by the invention can be widely applied to the technical field of geothermal power generation.

Description

Technical field [0001] The invention relates to an energy conversion system in the technical field of geothermal power generation, in particular to an energy conversion system for CO 2 It is the energy conversion system in the enhanced geothermal system (EGS) of the working fluid. Background technique [0002] Geothermal resources are rock thermal energy, geothermal fluid heat and associated useful components that can be scientifically and reasonably developed from the crust under current technical and economic conditions and geological conditions. At present, the world's mining of geothermal energy for power generation is faster and faster, and the mining depth is getting deeper and deeper. Power generation systems used for power generation from medium and low temperature geothermal resources, such as dual working fluid cycle, flash vaporization, Kalina cycle and other system technologies, are gradually mature and have a certain commercial basis. [0003] EGS is the abbreviation ...

AI Technical Summary

Problems solved by technology

However, the use of water as geothermal fluid has some disadvantages: 1. The water injected into the ground is seriously lost, with a loss rate as low as 10% and as high as 78%.

2. For heat sources with a temperature higher than the critical temperature of water, due to the dissolution and precipitation of minerals due to the thermochemical interaction between water and rock formations, short circuits or blockages occur between injection wells and production wells, which affect geothermal fluids endothermic

However, using CO 2 The conversion of thermal energy into electricity by using water as geothermal fluid and directly entering the energy conversion system is less efficient than the flash cycle using water as geothermal fluid, which becomes 2 Barriers to EGS deployment as geothermal fluids

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