Pressurization and heat absorption transcritical cycle hot dry rock geothermal power generation model based on CO2 mixed working medium

Abstract

The invention relates to a pressurization and heat absorption transcritical cycle hot dry rock geothermal power generation model based on a CO2 mixed working medium, which comprises a geothermal watercycle, a mixed working medium cycle and a cooling water cycle; and an underground coaxial sleeve heat exchanger is arranged in the mixed working medium cycle. The innovation is reflected in that a pressurization and heat absorption process is realized by utilizing a gravity field, so that the cycle heat absorption capacity is increased, and the cycle power generation is increased. A binary mixedworking medium composed of CO2 and an organic working medium is adopted; and therefore, a transcritical cycle with pressurization heat absorption and temperature reduction heat release can be achieved, irreversibility of heat exchange of a heat source and a cold source can be effectively reduced, and the cycle efficiency is improved. The mixed working medium adopted by the cycle comprises (but notlimited to) CO2 / R32, CO2 / R161, CO2 / R1270, CO2 / R1234yf, CO2 / R134a, CO2 / R152a and CO2 / R1234ze. The pressurization and heat absorption transcritical circulation hot dry rock geothermal power generationmodel based on the CO2 mixed working medium mainly aims at hot dry rock geothermal resources, but is not limited to the hot dry rock geothermal resources; and the power generation system is also suitable for application occasions of other binary cycle geothermal power generation systems.

Description

technical field [0001] The invention belongs to the field of energy application technology, and relates to the technical application of converting geothermal energy into mechanical energy, especially a CO-based 2 Model of supercharged endothermic transcritical cycle hot dry rock geothermal power generation with mixed working fluid. Background technique [0002] At present, energy saving and emission reduction is the key object of the state's support for development, and medium and low temperature power generation technology is one of the research hotspots, and it is also the direction of industrialization promotion. For medium and low temperature geothermal energy, its energy utilization efficiency is not high due to its low energy grade. How to make more effective use of medium and low temperature geothermal resources has become a major research direction in the world. [0003] Medium and low temperature geothermal resources are mainly used in power generation, industrial...

AI Technical Summary

Problems solved by technology

[0004] But completely relying on the CO driven by the thermosiphon effect 2 Pure working fluid generally can only maintain a small circulation flow, so the heat taken away from the geothermal well is also limited.

In addition, because CO 2 The critical temperature is lower, usually the CO 2 The power generation cycle is a supercritical Brayton cycle, and the cycle is subject to the use of expensive compact large-area heat exchangers. When using the Brayton cycle, CO 2 The outlet pressure of the turbine is often above the critical pressure, and the cycle efficiency is further limited

Images