阅读说明：本技术 一种基于自然循环原理的原位取热热电联产系统 (In-situ heat-taking cogeneration system based on natural circulation principle ) 是由 *** 黄江 孙立成 莫政宇 李碧雄 李存宝 高明忠 龙西亭 唐继国 杨伟 于 2020-05-21 设计创作，主要内容包括：本发明公开一种基于自然循环原理的原位取热热电联产系统,其包括存储有有机工质的工质储存罐以及全封闭式自然循环回路,所述全封闭式自然循环回路包括主蒸气管以及若干个设置在所述主蒸气管上的支路管道,所述支路管道的两端均与所述主蒸气管连通并各自形成封闭循环回路；所述主蒸气管内位于所述支路管道的两端之间的位置设置有发电系统,所述支路管道上均设置有与所述工质储存罐连通的工质注入口,以及与外部地源热泵装置连通的冷凝器。本发明成功实现了对地热能的原位取热,不会造成抽取地下水后出现回灌、地下水流失、地质条件变化等问题；所述系统为全封闭式回路,采用了自然循环原理,无需外部动力驱动,能够长时间持续运行,降低维修成本。(The invention discloses an in-situ heat and power cogeneration system based on a natural circulation principle, which comprises a working medium storage tank for storing organic working media and a totally-enclosed natural circulation loop, wherein the totally-enclosed natural circulation loop comprises a main steam pipe and a plurality of branch pipelines arranged on the main steam pipe, and two ends of each branch pipeline are communicated with the main steam pipe and respectively form a closed circulation loop; and a power generation system is arranged in the main steam pipe between two ends of the branch pipeline, and the branch pipeline is provided with a working medium injection port communicated with the working medium storage tank and a condenser communicated with an external ground source heat pump device. The invention successfully realizes the in-situ heat extraction of geothermal energy, and can not cause the problems of recharge, groundwater loss, geological condition change and the like after groundwater extraction; the system is a totally enclosed loop, adopts a natural circulation principle, does not need external power drive, can continuously run for a long time, and reduces the maintenance cost.)

1. An in-situ heat and power cogeneration system based on a natural circulation principle is characterized by comprising a working medium storage tank for storing organic working medium and a totally-enclosed natural circulation loop, wherein the totally-enclosed natural circulation loop comprises a main steam pipe and a plurality of branch pipelines arranged on the main steam pipe, and two ends of each branch pipeline are communicated with the main steam pipe and respectively form a closed circulation loop; and a power generation system is arranged in the main steam pipe between two ends of the branch pipeline, and the branch pipeline is provided with a working medium injection port communicated with the working medium storage tank and a condenser communicated with an external ground source heat pump device.

2. The in-situ heat and power cogeneration system based on the natural circulation principle of claim 1, wherein a plurality of the branch pipes are arranged around an axis centering on the main steam pipe, and adjacent branch pipes are staggered by a predetermined distance in a longitudinal direction.

3. The in-situ heat and power cogeneration system based on the natural circulation principle of claim 1, wherein the working medium injection ports are provided with regulating valves.

4. The in-situ heat and power cogeneration system based on the natural circulation principle of any one of claims 1 to 3, wherein the branch pipeline comprises a transverse condensing section pipeline, a vertical preheating section pipeline and a transverse boiling section pipeline which are connected in sequence, the transverse condensing section pipeline is positioned above the power generation system, and the transverse boiling section pipeline is positioned below the power generation system.

5. The in-situ combined heat and power generation system based on the natural circulation principle as claimed in claim 4, wherein the power generation system comprises two power generation units which are arranged in sequence from bottom to top, and each power generation unit comprises a driving expander and a generator which generates electric energy under the driving of the driving expander.

6. The cogeneration system according to claim 4, wherein said transverse condensing section tubes are inclined downward in the direction of vapor flow and at an angle α to the horizontal.

7. An in-situ cogeneration system based on the natural circulation principle according to claim 6, wherein said transverse boiling section tubes are inclined upward along the direction of vapor flow and at an angle α to the horizontal.

8. An in-situ cogeneration system based on the natural circulation principle according to claim 7, wherein said α angle is 10 ° -60 °.

9. The in-situ heat and power cogeneration system based on the natural circulation principle of claim 4, wherein the condenser is arranged on the transverse condensing section pipeline, a heat exchange pipeline is arranged in the condenser, and the condenser is communicated with the external ground source heat pump device through the heat exchange pipeline.

10. The in-situ heat and power cogeneration system based on the natural circulation principle of claim 1, wherein the organic working medium is freon.

Technical Field

The invention relates to the field of clean energy equipment, in particular to an in-situ heat-taking cogeneration system based on a natural circulation principle.

Background

The earth's interior is almost an inexhaustible energy treasure house, and the heat contained in the earth within 5000 meters from the earth surface is as high as 140 × 10⁶EJ (about 5000 trillion standard coal) can be used for 2800 years (calculated by annual consumption of 500 EJ) by human beings if only 1% is mined, but due to the limitation of technology and economy, the cumulative geothermal power generation installed capacity is 13.9GW only accounting for 0.55% of the whole new energy power generation installed capacity by 2019. The geothermal resources in China are quite rich and account for 1/6 of global geothermal resources, and according to the investigation and evaluation results of 2015 by the Chinese geological survey bureau, the national hydrothermal geothermal resource amount is reduced to 1.25 trillion tons of standard coal, and the annual exploitable resource amount is reduced to 19 trilliotons of standard coal. Since 2010, China has gained a relatively rapid development in the aspect of direct utilization of geothermal heat, now has leaped the world first and installed capacity has exceeded 20000MW by the end of 2018; however, the installed capacity of China in the aspect of geothermal power generation is only 45MW, and only accounts for about 0.2% of the installed capacity of the world thermoelectric power generation.

The existing geothermal utilization technology in China mainly adopts direct utilization, the direct utilization mainly adopts a ground source heat pump technology, and geothermal power generation mainly adopts a flash evaporation and double loop mode. In the prior art, the underground heat storage is carried out of the ground for utilization by water circulation under most conditions. Two patents relate to more advanced geothermal heat utilization methods that do not take water for heat extraction. A patent CN201910171547.0 entitled geothermal energy composite operation system mainly designs two heat-taking systems, namely a middle-deep geothermal underground heat supply system and a shallow buried pipe system, and adopts the technical idea of 'taking heat but not taking water' to obtain geothermal energy by using external fluid media to provide power by a circulating pump, but working medium circulation of the system needs external power to drive, and energy consumption is high; and from the heat transfer mode, mainly rely on single-phase convection heat transfer, heat transfer capacity is limited. In a patent No. CN201820815738.7, a working medium phase change is utilized to drive a natural circulation process in a totally-enclosed loop, so that the system has the characteristic of taking heat but not taking water to a certain extent, but only a single heat pipe vertically buried underground is used for absorbing underground heat, the heat exchange area is small, high-temperature and high-pressure steam cannot be formed, and the realization of the corresponding natural circulation principle has difficulty; and when the liquid working medium formed by condensation of the condenser in the second patent enters the heat pipe through the condensation pipe, gas-liquid reverse flow can be formed, so that steam is prevented from rising to a certain extent, the humidity of the steam is increased, and pressure fluctuation of the system can be caused.

Accordingly, the prior art is yet to be improved and developed.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide an in-situ heat-taking cogeneration system based on a natural circulation principle, and aims to solve the problems that the prior art pollutes the underground environment, needs external driving force, has high operation and maintenance cost, has low heat exchange efficiency and the like when extracting geothermal energy.

The technical scheme of the invention is as follows:

an in-situ heat-taking cogeneration system based on a natural circulation principle comprises a working medium storage tank for storing organic working medium and a totally-enclosed natural circulation loop, wherein the totally-enclosed natural circulation loop comprises a main steam pipe and a plurality of branch pipelines arranged on the main steam pipe, and two ends of each branch pipeline are communicated with the main steam pipe and respectively form an enclosed circulation loop; and a power generation system is arranged in the main steam pipe between two ends of the branch pipeline, and the branch pipeline is provided with a working medium injection port communicated with the working medium storage tank and a condenser communicated with an external ground source heat pump device.

The in-situ heat-taking cogeneration system based on the natural circulation principle is characterized in that a plurality of branch pipelines are arranged around a shaft by taking the main steam pipe as a center, and the adjacent branch pipelines are staggered by a preset distance in the longitudinal direction.

The in-situ heat taking cogeneration system based on the natural circulation principle is characterized in that the positions of the working medium injection ports are provided with regulating valves.

The in-situ heat taking cogeneration system based on the natural circulation principle is characterized in that the branch pipeline comprises a transverse condensation section pipeline, a vertical preheating section pipeline and a transverse boiling section pipeline which are sequentially connected, wherein the transverse condensation section pipeline is positioned above the power generation system, and the transverse boiling section pipeline is positioned below the power generation system.

The in-situ heat-taking cogeneration system based on the natural circulation principle comprises two power generation units which are sequentially arranged from bottom to top, wherein each power generation unit comprises a driving expander and a generator which generates electric energy under the driving of the driving expander.

The in-situ heat-taking cogeneration system based on the natural circulation principle is characterized in that the transverse condensing section pipes are downwards inclined along the flowing direction of vapor and form an angle alpha with the horizontal plane.

The in-situ heat-taking cogeneration system based on the natural circulation principle is characterized in that the transverse boiling section pipeline inclines upwards along the flow direction of vapor and forms an angle alpha with the horizontal plane.

The in-situ heat-taking cogeneration system based on the natural circulation principle is characterized in that the alpha angle is 5-20 degrees.

The in-situ heat-taking cogeneration system based on the natural circulation principle is characterized in that the condenser is arranged on the transverse condensing section pipeline, a heat exchange pipeline is arranged in the condenser, and the condenser is communicated with the external ground source heat pump device through the heat exchange pipeline.

The in-situ heat-taking cogeneration system based on the natural circulation principle is characterized in that the organic working medium is pentafluoropropane (R245 ca).

Has the advantages that: the in-situ heat-taking cogeneration system based on the natural circulation principle can successfully realize in-situ heat taking of geothermal energy, namely 'heat taking does not take water', does not cause the problems of recharge, groundwater loss, geological condition change and the like after groundwater is extracted, and simultaneously does not cost a large amount of water quality treatment cost and power consumption cost due to groundwater extraction; the system has the advantages of flexible site selection, convenient arrangement, safe and stable system, totally enclosed loop, green and environmental protection, no emission of pollutants such as waste gas, waste liquid, waste residue and the like, and no pollution to underground water; meanwhile, the whole system adopts a natural circulation principle, does not need external power drive, can continuously run for a long time, and reduces the maintenance cost.

Drawings

Fig. 1 is a schematic structural diagram of an in-situ heat-taking cogeneration system based on the natural circulation principle according to a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram of a closed circulation loop formed by a single branch pipe and a main steam pipe according to the present invention.

Fig. 3 is a working schematic diagram of an in-situ heat-taking cogeneration system based on the natural circulation principle.

Detailed Description

The invention provides an in-situ heat-taking cogeneration system based on a natural circulation principle, and the invention is further described in detail below in order to make the purpose, technical scheme and effect of the invention clearer and clearer. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Although the ground source heat pump technology is mature, the ground source heat pump technology still has a plurality of problems: the heat environment of the underground heat source occurrence area is difficult to accurately master, and the design of a heat exchange system is difficult to form; the current drilling cost is still expensive, and the economy of the ground source heat pump is reduced; the unbalance of underground water mining and irrigation causes influence on underground environment, and even environmental pollution, ground settlement and the like can be caused; scaling of the water circulation system is difficult to solve, and long-term operation can reduce the economical efficiency of the system and the like. Ground collapse, flooding, ground building damage and the like are easily caused by the ground source heat pump system, many accidents are related to the change of underground geothermal occurrence environment, and particularly, the accidents are related to partial communication of an underground aquifer or a recharging process more closely, so that stricter requirements are required to be provided for ground source heat pump system installation project demonstration, well drilling, recharging processes and the like. In the underground water source heat pump, a production well, an injection well, a submersible pump and an underground water heat exchanger often suffer from scaling and blocking, which are always the problems which are difficult to completely solve in the open type underground source heat pump technology.

Based on the problems existing in the prior art, the invention provides an in-situ heat and power cogeneration system based on a natural circulation principle, which comprises a totally-enclosed natural circulation loop 10 and a working medium storage tank 20 for storing organic working medium, wherein the totally-enclosed natural circulation loop 10 comprises a main steam pipe 11 and a plurality of branch pipelines 12 arranged on the main steam pipe 11, and two ends of each branch pipeline 12 are communicated with the main steam pipe 11 and respectively form a closed circulation loop; a power generation system 13 is arranged in the main steam pipe 11 between the two ends of the branch pipeline, and the branch pipeline 12 is provided with a working medium injection port 14 communicated with the working medium storage tank and a condenser 15 communicated with an external ground source heat pump device.

In this embodiment, as shown in fig. 2 to 3, the main steam pipe 11 and the branch pipeline 12 in the totally enclosed natural circulation loop 10 are partially embedded in a rock soil layer 30, the branch pipeline 12 includes a transverse condensation section pipeline 121, a vertical preheating section pipeline 122 and a transverse boiling section pipeline 123 which are connected in sequence, the transverse condensation section pipeline 121 is located above the power generation system 13, and the transverse boiling section pipeline 123 is located below the power generation system 13. The organic working medium in the working medium storage tank 2 is injected into the branch pipelines 12 embedded in the rock soil layer 30 through the working medium injection port 14, the organic working medium can reach the depth of 3000 meters underground under the action of gravity and pressure regulation, and by combining with the specific system working principle shown in fig. 3, the organic working medium can be heated by the vertical preheating section pipeline 122 and the transverse boiling section pipeline 123 in sequence and then reaches the superheating section pipeline 16 in the main steam pipe 11, the organic working medium finally forms high-temperature and high-pressure superheated steam from preheating, boiling and superheating, the superheated steam of each branch pipeline 12 converges into the main steam pipe 11, and the superheating degree of the steam is further increased through the continuous heating of the superheating pipeline 16, so that the thermal parameters of the steam are improved; the steam enters a power generation system 13 arranged in the main steam pipe 11 and outputs electric energy, conversion from geothermal energy to electric energy is realized, the pressure of the steam is obviously reduced, and the steam is redistributed to each branch pipeline 12 after reaching the ground. After entering the branch pipeline 12, the steam is condensed into liquid state again after passing through the condenser 15, and the heat released by the condenser is absorbed by an external ground source heat pump device communicated with the condenser, so that heat is supplied to the ground source heat pump system, and finally, the functions of in-situ heat extraction and cogeneration of geothermal energy are realized.

The in-situ heat-taking cogeneration system based on the natural circulation principle provided by the embodiment adopts the totally-enclosed natural circulation loop, successfully realizes the scheme of only taking heat and not taking water of geothermal energy, does not cause unbalanced underground water mining and irrigation to influence the underground environment, is green and environment-friendly, does not discharge pollutants such as waste gas, waste liquid, waste residue and the like, and does not pollute the underground water; meanwhile, the system has no scaling problem of a water circulation system, is flexible in site selection, convenient to arrange and safe and stable; the natural circulation of the flowing of the working medium is driven by the phase change of the organic working medium under the heating action of the terrestrial heat, the liquid working medium is continuously heated by the terrestrial heat in an underground pipeline, the liquid working medium is boiled and evaporated to form high-temperature and high-pressure steam, the steam is applied by a generator system and cooled and condensed by a condenser to return to the liquid state again, the natural circulation process of the liquid organic working medium, the steam and the liquid organic working medium is formed, the geothermal energy can be continuously extracted, the external power drive is not needed, the operation can be continuously carried out for a long time, and the operation and maintenance cost is; in the embodiment, the condenser is used as an evaporator of an external ground source heat pump (condensation of the condenser is realized by evaporation and heat absorption of working medium of the ground source heat pump) besides being used for power generation of the generator system by absorbing high-temperature and high-pressure steam formed by geothermal heat, so that the condensed heat is absorbed and utilized by the ground source heat pump, and the system realizes cogeneration functions of power generation and heat supply at the same time.

In some embodiments, the working medium injection ports 14 are provided with adjusting valves 17, the pressure of the organic working medium entering the branch pipelines 12 can be adjusted through the adjusting valves 17, and the pressure balance in each branch pipeline 12 is adjusted by utilizing the gravity head of the organic working medium.

In some embodiments, as shown in fig. 1, several of the branch pipes 12 are arranged around the main steam pipe 11, and adjacent branch pipes 12 are longitudinally offset by a predetermined distance. Specifically, since the geothermal energy which can be transmitted per unit time in the rock soil layer 30 at a certain depth is limited, if the plurality of branch pipes 12 are all disposed at the same depth, there may occur an insufficient amount of heat absorbed by one branch pipe 12, thereby reducing the heat exchange efficiency, resulting in a reduction in the heat and power production efficiency of the in-situ cogeneration system. In this embodiment, the plurality of branch pipes 12 are arranged around the main steam pipe 11, and the adjacent branch pipes 12 are staggered by a predetermined distance in the longitudinal direction, so that the heat absorption of the branch pipes 12 is not affected by each other, and the heat exchange efficiency is improved. The predetermined distance of the longitudinal offset of the adjacent branch pipes 12 may be substantially according to the actual geothermal distribution and the heat demand of the geothermal energy, so as to utilize the geothermal energy to the maximum extent, for example, the predetermined distance of the longitudinal offset of the adjacent branch pipes 12 may be 10 meters, 15 meters, 20 meters, etc.

In some embodiments, the power generation system 13 includes two power generation units arranged in sequence from bottom to top, and the power generation units include a driving expander and a generator that generates electric power under the driving of the driving expander. The condenser 15 is arranged on the transverse condensing section pipeline 121, a heat exchange pipeline is arranged in the condenser 15, and the condenser 15 is communicated with the external ground source heat pump device through the heat exchange pipeline. Specifically, as shown in fig. 1-2, the power generation system includes a primary power generation unit 131 and a secondary power generation unit 132 from bottom to top, the liquid organic working medium is heated, boiled and evaporated by geothermal energy in an underground pipeline to form high-temperature and high-pressure steam, the high-temperature and high-pressure steam is used for power generation by the primary power generation unit 131 and the secondary power generation unit 132 and for cooling and condensation by the condenser, and the steam returns to the liquid state again, so that a natural circulation process of the liquid organic working medium-steam-liquid organic working medium is formed, geothermal energy can be extracted continuously, and external power drive is not needed; in this embodiment, the liquid organic working medium forms high-temperature and high-pressure steam by absorbing geothermal heat, the high-temperature and high-pressure steam drives the expander and drives the generator system to generate electricity, and the heat released by the condenser is provided to the external ground source heat pump system.

In some embodiments, as shown in fig. 1-3, the transverse condensing section tubes 121 are inclined downwardly in the direction of vapor flow and at an angle α to the horizontal in order to facilitate the condensed liquid organic working fluid to enter the bypass tubes 12 under the influence of gravity.

In some embodiments, as shown in FIGS. 1-3, to reduce flow resistance and allow vapor to more easily enter the primary vapor tubes 11, the transverse boiling stage tubes 123 are inclined upwardly in the direction of vapor flow and at an angle α to the horizontal.

In some embodiments, the α angle is 5 ° to 20 °, by way of example, the α angle may be 5 °,10 °,15 °,20 °.

In some embodiments, the organic working fluid is a low boiling point organic solvent, and by way of example, the organic working fluid may be pentafluoropropane (R245ca), but is not limited thereto.

In conclusion, the in-situ heat and power cogeneration system based on the natural circulation principle provided by the invention adopts the totally-enclosed natural circulation loop, successfully realizes the scheme of only taking heat and not taking water for geothermal energy, does not cause the unbalance of underground water mining and irrigation to influence the underground environment, is green and environment-friendly, does not discharge pollutants such as waste gas, waste liquid, waste residue and the like, and does not pollute the underground water; meanwhile, the system has no scaling problem of a water circulation system, is flexible in site selection, convenient to arrange and safe and stable; the natural circulation of the flowing of the working medium is driven by the phase change of the organic working medium under the heating action of the terrestrial heat, the liquid working medium is continuously heated by the terrestrial heat in an underground pipeline, the liquid working medium is boiled and evaporated to form high-temperature and high-pressure steam, the steam is applied by a generator system and cooled and condensed by a condenser to return to the liquid state again, the natural circulation process of the liquid organic working medium, the steam and the liquid organic working medium is formed, the geothermal energy can be continuously extracted, the external power drive is not needed, the operation can be continuously carried out for a long time, and the operation and maintenance cost is; in the embodiment, the condenser is used as the evaporator of the external ground source heat pump besides being used for generating power by the generator system by absorbing high-temperature and high-pressure steam formed by geothermal heat, so that the condensed heat is absorbed and utilized by the ground source heat pump, and the system realizes the cogeneration functions of generating power and supplying heat simultaneously.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.