CN-121993908-A - Deep geothermal energy large well deep evaporator and cogeneration system

CN121993908ACN 121993908 ACN121993908 ACN 121993908ACN-121993908-A

Abstract

The invention discloses a deep geothermal energy large well depth evaporator and a cogeneration system, wherein the deep geothermal energy large well depth evaporator comprises a first pipe body, a second pipe body and a sectional type buffer liquid pool unit, wherein the first pipe body is formed by the upper part of a middle temperature section and the lower part of a high temperature section, the first pipe body forms a high temperature heat taking channel, the second pipe body is arranged outside the first pipe body and is positioned at the upper part of the first pipe body, the middle temperature heat taking channel is formed between the second pipe body and the first pipe body, and the sectional type buffer liquid pool unit is arranged at intervals on the lower part of the first pipe body and the second pipe body and is used for realizing gradual distribution and evaporation of working media. Compared with the existing deep geothermal energy closed type heat extraction technology, the large well deep evaporator heat extraction module is matched with reservoirs with different depths through the stepped reducing pipe body structure, and the hierarchical heat extraction of high-grade and medium-grade steam heat energy is realized. The invention can obviously improve the heat-power conversion efficiency of the deep geothermal energy power generation system while effectively strengthening the heat-taking performance of the large well deep evaporator.

Inventors

CHEN YONGPING
ZHANG CHENGBIN
WANG JIAJUN
CHEN XI
HUANG YONGPING
WU SUCHEN

Assignees

东南大学

Dates

Publication Date: 20260508
Application Date: 20260408

Claims (10)

1.A deep geothermal energy large well deep evaporator, comprising: The first pipe body is formed by the upper part of the middle temperature section and the lower part of the high temperature section, and forms a high temperature heat taking channel; The second pipe body is arranged outside the first pipe body and is positioned at the upper part of the first pipe body, and a medium-temperature heat taking channel is formed between the second pipe body and the first pipe body; and the sectional open type buffer liquid pool units are arranged at intervals on the lower part of the first pipe body and the second pipe body and are used for realizing step-by-step distribution and evaporation of working media.
2. The deep geothermal energy large-well deep evaporator according to claim 1, wherein the sectional open type buffer liquid pool unit comprises 1 main buffer liquid pool and m matched secondary buffer liquid pools, the upper main buffer liquid pool and the lower main buffer liquid pool are communicated through overflow pipes, the top ends of the overflow pipes are slightly higher than the liquid level of the main buffer liquid pools, the lower ends of the overflow pipes extend into the next main buffer liquid pools to realize that working mediums spontaneously flow along the overflow pipes stably under the action of gravity, each main buffer liquid pool is connected with a main liquid distribution pipe, the secondary buffer liquid pools are communicated with the main liquid distribution pipe of the corresponding main buffer liquid pools through branch liquid distribution pipes, liquid level valves are arranged in the branch liquid distribution pipes, and when the liquid level of the secondary buffer liquid pools reaches a preset height, the liquid level valves are closed to ensure that working mediums of the present stage are fully evaporated into steam of a corresponding depth temperature zone so as to realize the accurate distribution of working mediums of each open type liquid pool of an evaporation section.
3. The deep geothermal energy large well deep evaporator of claim 2, wherein the geometry of the primary buffer pool satisfies w 1 < D and h 1 < D, wherein D is the first tube inner diameter, w 1 is the width of the primary buffer pool, h 1 is the height of the primary buffer pool, and the geometry of the secondary buffer pool satisfies w 2 < w 1 and h 2 <h 1 ,w 2 is the width of the secondary buffer pool, and h 2 is the height of the secondary buffer pool.
4. The deep geothermal energy large well deep evaporator according to claim 1, wherein a heat insulating reinforcing structure is provided on an upper portion of the first pipe body and the second pipe body.
5. The deep geothermal energy large well deep evaporator of claim 4, wherein the thermally insulating reinforcing structure is an aerogel filled composite insulation structure disposed on a surface of the medium temperature heat extraction channel.
6. A deep geothermal energy closed heat and heat cogeneration system, comprising: A deep geothermal energy large well depth evaporator as defined in any one of claims 1 to 5; the first-stage turbine is connected with the Gao Wenqu hot channel and is used for converting high-temperature steam flowing out of the high-temperature heat taking channel into mechanical energy and driving the generator to generate electricity; The second-stage turbine is connected with the medium-temperature heat-taking channel and is used for converting medium-temperature steam flowing out of the medium-temperature heat-taking channel into mechanical energy and driving the generator to generate electricity.
7. The closed heat and co-generation system of deep geothermal energy of claim 6, further comprising: and the steam generated by the secondary turbine enters the ground condensation module through a steam exhaust pipeline.
8. The closed type heat collection and cogeneration system for deep geothermal energy according to claim 6, wherein the ground condensation module comprises a condenser, a liquid storage tank, a working medium pump and a return pipe, wherein the condenser condenses steam into liquid working medium and stores the liquid working medium in the liquid storage tank, and the working medium pump is used for leading the working medium in the liquid storage tank to the segmented buffer liquid pool unit through the return pipe.
9. The closed heat and co-generation system of deep geothermal energy of claim 6, further comprising: The system comprises a combined heat and power module, wherein the combined heat and power module comprises a user side, a cooling tower, a heating conveying pipeline, a temperature climbing rate monitoring unit, an electricity utilization on-line identification unit, a liquid supplementing controller, a load self-adaptive controller and a condensing pressure controller, when the ground condensing module conveys heat exchange media of a condenser to the user side and the cooling tower through the heating conveying pipeline, the temperature climbing rate monitoring unit and the electricity utilization on-line identification unit identify the temperature rise of an evaporator and the electricity utilization load in real time, acquire signals are fed back to the liquid supplementing controller and the load self-adaptive controller respectively, the opening degree of a pipeline valve is adjusted in a self-adaptive mode, the direct dissipation of the dynamic combined heat and power of a building in a heating season is realized, and after the heat exchange media of the condenser are subjected to heat exchange by the user side or the cooling tower, the condensing pressure controller adjusts the pressure in the condenser in real time according to requirements, so that the decoupling control of the system is realized, and the efficiency and the stability of the combined heat and power system are improved.
10. The closed heat collection and cogeneration system of the deep geothermal energy of claim 6, wherein the steam discharged after the primary turbine works is mixed with the medium temperature steam flowing out of the medium temperature heat collection channel and enters the secondary turbine to generate electricity.

Description

Deep geothermal energy large well deep evaporator and cogeneration system Technical Field The invention relates to the technical field of geothermal energy exploitation and utilization, in particular to a deep geothermal energy closed type heat-taking and cogeneration system. Background Geothermal energy is a clean renewable energy source which can be continuously and stably supplied and is not limited by weather factors such as weather and snow, day and night alternation and the like. The distribution in China is wide, the reserves are rich, and especially, the geothermal energy in the middle and deep layers accounts for more than 99% of the total reserves. The deep geothermal energy (usually with the burial depth of more than 3000 m and the bottom hole temperature of more than 150 ℃ in general) is used as clean renewable energy source with continuous and stable energy supply and higher grade, and has the unique properties of high energy density and capability of directly driving high-efficiency power generation. Thermal storage is the basic carrier for the occurrence of deep geothermal energy. In China, deep geothermal energy is mainly endowed to a compact and less Kong Shaoshui carbonate type thermal storage (the porosity is less than 5%), and obvious differences exist in burial depth, ground temperature grade, lithology and permeability, so that research and study on theory, method and technology of efficient geothermal exploitation are needed. In addition, the direct water heating type open type heat extraction technology has a series of problems of difficult recharging, ecological damage and the like. Thus, the "heat extraction only without water" closed heat extraction technique has become the preferred solution. Particularly, aiming at the clean heat supply requirement of super-large load and long period, the large-scale efficient and economical development of deep geothermal energy by adopting a closed heat-taking system is promoted. However, due to the dependence of the operation process on the driving force of an external pump, the coaxial casing scheme faces challenges such as rapid increase of energy consumption, difficult equipment maintenance and the like in a large well depth scene with the depth of more than 3000m, and the requirements of efficient development of deep geothermal resources are difficult to meet. In recent years, the passive heat-taking technology of the ultra-long evaporator has become a research hot spot in the geothermal energy field by virtue of the advantages of excellent heat transfer performance, no need of external power, large-depth heat-taking capability (up to thousands of meters) and the like. The technology utilizes a circulation mechanism of spontaneous evaporation/condensation, upward flow and condensation of working medium in a heat-taking section to realize heat transfer. However, the existing researches show that the technology has obvious technical bottlenecks that firstly, rising steam flow resistance, frictional shear resistance and gravity pressure drop of a backflow working medium along a wall surface are mutually overlapped, so that the overall heat extraction efficiency of the system is low, secondly, the phenomenon of liquid accumulation at the bottom of a pipe body inhibits evaporation/boiling behaviors, heat transfer performance is weakened, and thirdly, heat of different grades of a thermal reservoir cannot be fully utilized, so that the heat-power conversion efficiency of the system is low. Therefore, the technical problems are limited, and the conventional passive heat-taking technology of the ultra-long evaporator is difficult to adapt to the basic requirements of efficient heat-taking utilization and cogeneration of deep geothermal energy. In order to break through the performance limit of the passive heat-taking technology of the ultra-long evaporator, the prior researches mostly optimize the performance of the ultra-long evaporator through structural innovation, thereby realizing the high-efficiency utilization of the deep geothermal energy. However, the existing optimization scheme still has the following remarkable technical bottlenecks that (1) the existing ultra-long evaporator mostly adopts a single-diameter pipe body structure, cannot adapt to temperature gradient differences of deep layers at different depths, high-pressure steam in a high-temperature region can inhibit vaporization phase change in a medium-temperature region, so that high-grade steam and medium-grade steam are mixed and wasted, and the heat extraction efficiency is low. Meanwhile, the pressure difference between the upper part and the lower part of the tube body of the ultra-long evaporator can reach more than 25MPa (the bottom pressure of 3000 meters is approximately equal to 30MPa, the shallow pressure of 500 meters is approximately equal to 5 MPa), and the huge pressure gradient leads the working medium to form serious effusion at the middle lower part, thereby di