Cogeneration coupled geothermal energy cross-seasonal energy utilization system and method

Abstract

The invention discloses a combined heat and power generation coupled geothermal energy cross-seasonal energy utilization system and method, and belongs to the technical field of comprehensive utilization of energy, the combined heat and power generation coupled geothermal energy cross-seasonal energy utilization system comprises a combined heat and power generation power plant used for generating power and generating waste heat in a non-heating season, and the combined heat and power generation power plant is connected with a first geothermal well and a second geothermal well through a geothermal heat exchange station; meanwhile, the first geothermal well and the second geothermal well are connected with a town heat exchange station through a geothermal heat exchange station, and the town heat exchange station supplies heat to town users. According to the method, the generator set generates power and surfs the internet in the non-heating season, the power generation income is obtained, the annual operation time of the back pressure unit is prolonged to 10-12 months from less than or equal to 6 months, and the annual energy output is increased by 40%; meanwhile, the combined heat and power generation unit can be coupled to achieve gradient utilization of heat energy or participate in peak regulation, idle backpressure turbine resources are effectively utilized, coal consumption is reduced, clean heat supply is achieved, and energy conservation and emission reduction and regional clean low-carbon development are promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive energy utilization, and particularly relates to a cogeneration-coupled geothermal seasonal energy utilization system and method. Background Art

[0002] Facing the dual pressures of energy security and environmental governance, it is imperative to vigorously promote the green and low-carbon transformation of energy and achieve the development of renewable energy. Geothermal resources are a kind of green, low-carbon, clean, environmentally friendly, safe and high-quality renewable energy. In recent years, the scale of medium-deep hydrothermal geothermal heating utilization in China has been continuously expanding, playing an important role in northern clean heating and air pollution prevention.

[0003] Aquifer thermal energy storage is an energy storage system that uses underground aquifers as a medium to store thermal energy in the form of hot water in underground aquifers. It extracts and injects groundwater from the aquifer through groundwater wells to achieve thermal energy storage and recovery. Aquifer energy storage can compensate for the imbalance in the distribution of energy supply and demand in time / space, can comprehensively utilize various forms of renewable energy, reduce dependence on fossil fuels, and provide a good solution for energy conservation, emission reduction and environmental protection.

[0004] At present, when back-pressure units are used for heating in northern China, the back-pressure units are started in the warm season, and the start-up time is 4 - 6 months, and they are shut down in the non-heating season, and the shutdown time is as long as 6 - 8 months, resulting in idle equipment and low coal consumption efficiency. At the same time, it also leads to a significant seasonal imbalance in energy supply and demand and a lack of seasonal heat storage means. Summary of the Invention

[0005] In order to solve the problems in the prior art that the back-pressure units are shut down in the non-heating season, and the shutdown time is as long as 6 - 8 months, resulting in idle equipment and low coal consumption efficiency; at the same time, to solve the problems in the prior art that there is a significant seasonal imbalance in energy supply and demand and a lack of seasonal heat storage means. The present invention provides a cogeneration-coupled geothermal seasonal energy utilization system and method, which can increase the annual operating time of the back-pressure units from ≤6 months to 10 - 12 months, effectively utilize the idle back-pressure machine resources, and at the same time can provide a seasonal heat storage means.

[0006] The technical solutions adopted by the cogeneration-coupled geothermal seasonal energy utilization system and method of the present invention are as follows:

[0007] A cogeneration-coupled geothermal seasonal energy utilization system includes a cogeneration power plant for generating electricity and producing waste heat in the non-heating season. The cogeneration power plant is connected to a first geothermal well and a second geothermal well through a geothermal heat exchange station. At the same time, the first geothermal well and the second geothermal well are connected to an urban heat exchange station through the geothermal heat exchange station, and the urban heat exchange station provides heating for urban users.

[0008] A further improvement of the technical solution of the present invention lies in that: the geothermal heat exchange station includes a non-heating season heat exchanger located between the cogeneration power plant and the first geothermal well and the second geothermal well, and a heating season heat exchanger and a water source heat pump located between the first geothermal well and the second geothermal well and the urban heat exchange station; wherein, the heat source side of the non-heating season heat exchanger is connected to the cogeneration power plant, the geothermal water side of the non-heating season heat exchanger is connected to the first geothermal well and the second geothermal well, the heat source side of the heating season heat exchanger is connected to the first geothermal well and the second geothermal well, and the geothermal water side of the heating season heat exchanger is connected to the urban heat exchange station through the water source heat pump.

[0009] A further improvement of the above technical solution of the present invention lies in that: the cogeneration power plant is connected to the water inlet of the heat source side of the non-heating season heat exchanger through the first pipeline, the water outlet of the heat source side of the non-heating season heat exchanger is connected to the cogeneration power plant through the second pipeline, the water inlet of the geothermal water side of the non-heating season heat exchanger is connected to the first geothermal well through the third pipeline, and the water outlet of the geothermal water side of the non-heating season heat exchanger is connected to the second geothermal well through the fourth pipeline.

[0010] A further improvement of the above technical solution of the present invention lies in that: the water inlet of the heat source side of the heating season heat exchanger is connected with a fifth pipeline connected to the fourth pipeline, the water outlet of the heat source side of the heating season heat exchanger is connected with a sixth pipeline connected to the third pipeline, and at the same time, the user side of the heating season heat exchanger is connected to the water source heat pump and the water source heat pump is connected to the urban heat exchange station through connecting pipelines.

[0011] A further improvement of the above technical solution of the present invention lies in that: a high-temperature valve for the heating season is provided on the fifth pipeline, a low-temperature valve for the heating season is provided on the sixth pipeline, a low-temperature valve for the non-heating season is provided on the third pipeline on the side close to the non-heating season heat exchanger of the sixth pipeline, and a high-temperature valve for the non-heating season is provided on the fourth pipeline on the side close to the non-heating season heat exchanger of the fifth pipeline.

[0012] A method for utilizing cross-seasonal energy by coupling cogeneration and geothermal energy, using the above-mentioned system for utilizing cross-seasonal energy by coupling cogeneration and geothermal energy, includes a heat storage mode in the non-heating season and a heat supply mode in the heating season.

[0013] A further improvement of the above technical solution of the present invention lies in that: the heat storage mode in the non-heating season includes opening the high-temperature valve for the non-heating season and the low-temperature valve for the non-heating season, closing the high-temperature valve for the heating season and the low-temperature valve for the heating season, and injecting the waste heat of the cogeneration power plant into the second geothermal well for heat storage.

[0014] A further improvement of the above technical solution of the present invention is that the waste heat injection of the cogeneration power plant into the second geothermal well for heat storage is specifically as follows: while the generator set of the cogeneration power plant generates electricity, the generated waste heat is transported to the non-heating season heat exchanger, and at the same time, the groundwater in the first geothermal well is transported to the non-heating season heat exchanger to exchange heat with the waste heat generated by the generator set, and then the groundwater with increased temperature is transported to the second geothermal well for storage.

[0015] A further improvement of the above technical solution of the present invention is that the heating mode in the heating season includes closing the high-temperature valve in the non-heating season and the low-temperature valve in the non-heating season, and opening the high-temperature valve in the heating season and the low-temperature valve in the heating season, and transporting the heat stored in the second geothermal well to the urban heat exchange station to supply heat to urban users.

[0016] A further improvement of the above technical solution of the present invention is that the transportation of the heat stored in the second geothermal well to the urban heat exchange station to supply heat to urban users is specifically as follows: the geothermal water in the second geothermal well is transported to the heating season heat exchanger, and after cascade utilization by the heating season heat exchanger and the water source heat pump, it is transported to the urban heat exchange station for heat exchange, and at the same time, the groundwater with reduced temperature after heat exchange is transported to the first geothermal well for storage.

[0017] Due to the adoption of the above technical solution, the technical progress achieved by the present invention includes:

[0018] In the present invention, the generator set generates electricity and is connected to the grid in the non-heating season to obtain power generation income. The annual operating time of the back-pressure unit is increased from ≤6 months to 10 - 12 months, and the annual power generation increases by 40%. At the same time, the waste heat generated by the back-pressure unit is injected into the second geothermal well for storage through the geothermal heat exchange station. In the heating season, groundwater is extracted from the heat storage layer of the second geothermal well, and after cascade utilization by the geothermal heat exchange station, it is sent to the secondary heat supply network to expand the heating area, realize heating income, and solve the municipal heating gap. At the same time, it can be coupled with the cogeneration unit to realize cascade utilization of thermal energy or participate in peak shaving, effectively utilize the idle back-pressure machine resources, reduce coal consumption, realize clean heating, and promote energy conservation, emission reduction and regional clean and low-carbon development. Description of the Drawings

[0019] Figure 1 It is a schematic connection structure diagram of a cogeneration coupled geothermal energy seasonal energy utilization system of the present invention.

[0020] In the drawings: 1. Cogeneration power plant; 2. First geothermal well; 3. Second geothermal well; 4. Urban heat exchange station; 5. Non-heating season heat exchanger; 6. Heating season heat exchanger; 7. Water source heat pump; 8. First pipeline; 9. Second pipeline; 10. Third pipeline; 11. Fourth pipeline; 12. Fifth pipeline; 13. Sixth pipeline; 14. High-temperature valve in the heating season; 15. Low-temperature valve in the heating season; 16. Low-temperature valve in the non-heating season; 17. High-temperature valve in the non-heating season. Detailed Embodiments

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the specific embodiments and with reference to the accompanying drawings. In the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0022] This embodiment provides a cogeneration-coupled geothermal seasonal energy utilization system. When specifically arranged, the system refers to Figure 1 It can be seen that the above system includes a cogeneration power plant 1, which uses a back-pressure unit. The operation time in the non-heating season is 6 - 8 months, and it shuts down or participates in peak shaving during the heating season. At the same time, the cogeneration power plant 1 is connected to the first geothermal well 2 and the second geothermal well 3 through a geothermal heat exchange station. At the same time, the first geothermal well 2 and the second geothermal well 3 are connected to the urban heat exchange station 4 through the geothermal heat exchange station, and the urban heat exchange station 4 supplies heat to urban users. In this embodiment, the aquifer heat storage depth of the first geothermal well 2 and the second geothermal well 3 is 500 - 2000 meters. At the same time, in this embodiment, the waste heat generated during power generation by the cogeneration power plant 1 in the non-heating season is transported to the geothermal heat exchange station. The geothermal heat exchange station heats the groundwater in the first geothermal well 2 to 40 - 80°C and then transports it to the second geothermal well 3 for storage; during the heating season, the back-pressure unit in the cogeneration power plant 1 shuts down, and the groundwater in the second geothermal well 3 is transported to the geothermal heat exchange station. After being cascadedly utilized by the geothermal heat exchange station, it is sent to the secondary heat supply network to raise the temperature of the hot water supplied in the secondary network to 50 - 90°C, thereby supplying heat to urban users.

[0023] In this embodiment, the geothermal heat exchange station includes a non-heating season heat exchanger 5 located between the cogeneration power plant 1 and the first geothermal well 2 and the second geothermal well 3, and a heating season heat exchanger 6 and a water source heat pump 7 located between the first geothermal well 2 and the second geothermal well 3 and the urban heat exchange station 4; specifically, the heat source side of the non-heating season heat exchanger 5 is connected to the cogeneration power plant 1, the geothermal water side of the non-heating season heat exchanger 5 is connected to the first geothermal well 2 and the second geothermal well 3, the heat source side of the heating season heat exchanger 6 is connected to the first geothermal well 2 and the second geothermal well 3, and the geothermal water side of the heating season heat exchanger 6 is connected to the urban heat exchange station 4 through the water source heat pump 7.

[0024] During the non - heating season, the heat source side of the non - heating season heat exchanger 5 is connected to the cogeneration power plant 1. When the geothermal water side of the non - heating season heat exchanger 5 is connected to the first geothermal well 2 and the second geothermal well 3, the cogeneration power plant 1 is connected to the water inlet of the heat source side of the non - heating season heat exchanger 5 through the first pipeline 8. The water outlet of the heat source side of the non - heating season heat exchanger 5 is connected to the cogeneration power plant 1 through the second pipeline 9. The water inlet of the geothermal water side of the non - heating season heat exchanger 5 is connected to the first geothermal well 2 through the third pipeline 10, and the water outlet of the geothermal water side of the non - heating season heat exchanger 5 is connected to the second geothermal well 3 through the fourth pipeline 11.

[0025] During the heating season, when the heat source side of the heating season heat exchanger 6 is connected to the first geothermal well 2 and the second geothermal well 3, and the geothermal water side of the heating season heat exchanger 6 is connected to the urban heat exchange station 4 through the water source heat pump 7, the water inlet of the heat source side of the heating season heat exchanger 6 is connected with a fifth pipeline 12 which is connected to the fourth pipeline 11. The water outlet of the heat source side of the heating season heat exchanger 6 is connected with a sixth pipeline 13 which is connected to the third pipeline 10. At the same time, both between the user side of the heating season heat exchanger 6 and the water source heat pump 7, and between the water source heat pump 7 and the urban heat exchange station 4 are connected through connecting pipelines.

[0026] Furthermore, in this embodiment, a heating season high - temperature valve 14 is provided on the above - mentioned fifth pipeline 12, a heating season low - temperature valve 15 is provided on the above - mentioned sixth pipeline 13, a non - heating season low - temperature valve 16 is provided on the above - mentioned third pipeline 10, and the non - heating season low - temperature valve 16 is located on the side of the sixth pipeline 13 close to the non - heating season heat exchanger 5. A non - heating season high - temperature valve 17 is provided on the above - mentioned fourth pipeline 11, and the non - heating season high - temperature valve 17 is located on the side of the fifth pipeline 12 close to the non - heating season heat exchanger 5.

[0027] This embodiment also provides a method for cogeneration - coupled geothermal seasonal energy utilization, which includes two modes: non - heating season heat storage mode and heating season heat supply mode.

[0028] When in the non - heating season heat storage mode, the non - heating season high - temperature valve 17 and the non - heating season low - temperature valve 16 are opened, and the heating season high - temperature valve 14 and the heating season low - temperature valve 15 are closed. While the generator set of the cogeneration power plant 1 generates electricity, the waste heat generated is transported to the non - heating season heat exchanger 5. At the same time, the groundwater in the first geothermal well 2 is transported to the non - heating season heat exchanger 5 for heat exchange with the waste heat generated by the generator set, and then the groundwater with increased temperature is transported to the second geothermal well 3 for storage, so as to achieve the purpose of heat storage during the non - heating period.

[0029] When in the heating mode during the heating season, the geothermal water in the second geothermal well is transported to the heating-season heat exchanger, and after cascaded utilization through the heating-season heat exchanger and the water-source heat pump, it is transported to the urban heat exchange station for heat exchange. At the same time, the groundwater that has cooled after heat exchange is transported to the first geothermal well for storage, so as to facilitate heat storage during the next non-heating season.

[0030] In the above embodiment, the present invention provides a cogeneration-coupled geothermal seasonal energy utilization system and method. In the present invention, the power generation unit generates electricity and feeds it into the grid during the non-heating season to obtain power generation benefits. The annual operating time of the back-pressure unit is increased from ≤6 months to 10 - 12 months, and the annual power generation increases by 40%. At the same time, the waste heat generated by the back-pressure unit is injected into the second geothermal well for storage through the geothermal heat exchange station. During the heating season, groundwater is extracted from the heat storage layer in the second geothermal well, and after cascaded utilization through the geothermal heat exchange station, it is sent to the secondary heating pipe network to expand the heating area, realize heating benefits, and solve the municipal heating gap. At the same time, it can be coupled with the cogeneration unit to achieve cascaded utilization of heat energy or participate in peak shaving, effectively utilize the idle back-pressure machine resources, reduce coal consumption, realize clean heating, and promote energy conservation, emission reduction and regional clean and low-carbon development.

[0031] The above-described embodiments are only used to describe the preferred embodiments of the present invention, and do not limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various variations and improvements made by those of ordinary skill in the art to the technical solution of the present invention shall fall within the protection scope of the present invention. The technical content claimed by the present invention has been fully recorded in the claims.

Claims

1. A combined heat and power (CHP) coupled with seasonal geothermal energy utilization system, characterized in that: It includes a combined heat and power plant (1) for generating electricity and producing waste heat during the non-heating season. The combined heat and power plant (1) is connected to the first geothermal well (2) and the second geothermal well (3) through a geothermal heat exchange station. At the same time, the first geothermal well (2) and the second geothermal well (3) are connected to the urban heat exchange station (4) through the geothermal heat exchange station, and the urban heat exchange station (4) supplies heat to urban users.

2. The cogeneration-coupled geothermal seasonal energy utilization system according to claim 1, wherein: The geothermal heat exchange station includes a non-heating season heat exchanger (5) located between the combined heat and power plant (1) and the first geothermal well (2) and the second geothermal well (3), and a heating season heat exchanger (6) and a water source heat pump (7) located between the first geothermal well (2) and the second geothermal well (3) and the urban heat exchange station (4); wherein, the heat source side of the non-heating season heat exchanger (5) is connected to the combined heat and power plant (1), the geothermal water side of the non-heating season heat exchanger (5) is connected to the first geothermal well (2) and the second geothermal well (3), the heat source side of the heating season heat exchanger (6) is connected to the first geothermal well (2) and the second geothermal well (3), and the geothermal water side of the heating season heat exchanger (6) is connected to the urban heat exchange station (4) through the water source heat pump (7).

3. The cogeneration-coupled geothermal seasonal energy utilization system according to claim 2, wherein: The combined heat and power plant (1) is connected to the water inlet of the heat source side of the non-heating season heat exchanger (5) through the first pipeline (8), the water outlet of the heat source side of the non-heating season heat exchanger (5) is connected to the combined heat and power plant (1) through the second pipeline (9), the water inlet of the geothermal water side of the non-heating season heat exchanger (6)(5) is connected to the first geothermal well (2) through the third pipeline (10), and the water outlet of the geothermal water side of the non-heating season heat exchanger (5) is connected to the second geothermal well (3) through the fourth pipeline (11).

4. A cogeneration-coupled geothermal seasonal energy utilization system according to claim 3, characterized in that: The water inlet of the heat source side of the heating season heat exchanger (6) is connected with a fifth pipeline (12) connected to the fourth pipeline (11), the water outlet of the heat source side of the heating season heat exchanger (6) is connected with a sixth pipeline (13) connected to the third pipeline (10), and at the same time, the user side of the heating season heat exchanger (6), the water source heat pump (7), and the water source heat pump (7) and the urban heat exchange station (4) are all connected through connecting pipelines.

5. A cogeneration-coupled geothermal seasonal energy utilization system according to claim 4, characterized in that: A heating season high-temperature valve (14) is provided on the fifth pipeline (12), a heating season low-temperature valve (15) is provided on the sixth pipeline (13), a non-heating season low-temperature valve (16) is provided on the third pipeline (10) on the side close to the non-heating season heat exchanger (5), and a non-heating season high-temperature valve (17) is provided on the fourth pipeline (11) on the side close to the non-heating season heat exchanger (5).

6. A method for utilizing cross-seasonal energy by coupling combined heat and power with geothermal energy, characterized in that: Using the described combined heat and power coupled geothermal seasonal energy utilization system according to any one of claims 1-5, it includes a non-heating season heat storage mode and a heating season heat supply mode.

7. A method for cogeneration coupled with seasonal geothermal energy utilization according to claim 6, characterized in that: The non-heating season heat storage mode includes opening the non-heating season high-temperature valve (17) and the non-heating season low-temperature valve (16), closing the heating season high-temperature valve (14) and the heating season low-temperature valve (15), and injecting the waste heat of the combined heat and power plant (1) into the second geothermal well (3) for heat storage.

8. A method for cogeneration coupling geothermal energy for seasonal energy utilization according to claim 7, characterized in that: The specific heat storage method of injecting the waste heat of the cogeneration power plant (1) into the second geothermal well (3) is that while the generator set of the cogeneration power plant (1) generates electricity, the generated waste heat is transported to the non-heating season heat exchanger (5). At the same time, the groundwater in the first geothermal well (2) is transported to the non-heating season heat exchanger (5) to exchange heat with the waste heat generated by the generator set, and then the groundwater with increased temperature is transported to the second geothermal well (3) for storage.

9. A method for utilizing geothermal energy across seasons through combined heat and power generation according to claim 6, characterized in that: The heating mode in the heating season includes closing the non-heating season high-temperature valve (17) and the non-heating season low-temperature valve (16), and opening the heating season high-temperature valve (14) and the heating season low-temperature valve (15), and transporting the heat stored in the second geothermal well (3) to the urban heat exchange station (4) to supply heat to urban users.

10. A method for combined heat and power generation coupled with seasonal geothermal energy utilization according to claim 9, characterized in that: The specific method of transporting the heat stored in the second geothermal well (3) to the urban heat exchange station (4) to supply heat to urban users is to transport the geothermal water in the second geothermal well (3) to the heating season heat exchanger (6), and after cascade utilization by the heating season heat exchanger (6) and the water source heat pump (7), it is transported to the urban heat exchange station (4) for heat exchange. At the same time, the groundwater with reduced temperature after heat exchange is transported to the first geothermal well (2) for storage.

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