Geothermal Energy-Driven Integrated System for CO2 Hybrid Heating, Power Generation and Sequestration

Abstract

The present invention discloses an integrated system for geothermal energy-driven CO2 hybrid heating power generation and storage, including a geothermal water circulation pump, which is used to extract and transfer the hot water from the production well to the contact mixing heater. A liquid distribution pipe is arranged in the contact mixing heater, and the outlet end of the liquid distribution pipe is located inside the mixing heater. The liquid outlet end of the mixing heater is used to connect to the reinjection well; the liquid distribution pipe is used to receive CO 2； The swirl chamber is connected to the top of the contact mixing heater. The liquid outlet of the swirl chamber is connected to the bottom of the contact mixing heater. The top gas outlet of the swirl chamber is connected to the inlet of the expander. The outlet of the expander is connected to the inlet of the condenser. The outlet of the condenser is connected to the liquid distribution pipe. The circulating working medium CO2 directly exchanges heat with the geothermal fluid through the liquid distribution pipe and the liquid outlet. Compared with the traditional indirect contact heat exchange, the heat transfer efficiency is greatly improved, the heat transfer area is greatly reduced, and the investment cost is reduced.

Description

Technical Field

[0001] The present invention relates to an integrated technology of thermal power generation and CO2 sequestration, and particularly to an integrated system for CO2 hybrid heating power generation and sequestration driven by geothermal energy. Background Art

[0002] With the continuous development and growth of mankind, environmental pollution and resource shortage phenomena have gradually covered the globe. Therefore, environmental protection, energy conservation, and the development and utilization of new energy have become the development strategies of countries around the world. Developing new energy has become the key focus to alleviate energy shortage and environmental pollution. China has a vast territory, rich and widely distributed geothermal resources, with great application potential. Moreover, compared with other renewable energy sources, it has the advantages of stability, continuity, and high utilization rate. The reserves of hydrothermal geothermal resources in China are equivalent to 853 billion tons of standard coal, and the annual available resource amount is equivalent to 640 million tons of standard coal. The efficient utilization of geothermal energy is of great significance for energy conservation and emission reduction.

[0003] Carbon sequestration refers to transporting the collected CO2 to a suitable place and isolating it from the atmosphere for a long time by technical means. The current carbon sequestration technologies mainly include two types. The first is to inject high-pressure liquefied CO2 into the ocean floor. Based on the physical and chemical properties of CO2, below 2.5 km below sea level, CO2 mainly exists in a liquid form. Since its density is greater than that of seawater, this area is used as a safe area for ocean carbon sequestration. The second is to conduct geological sequestration of CO2. In the height range of 0.8 - 1.0 km underground, supercritical CO2 has fluid properties. Based on the change of the physical and chemical properties of CO2, geological carbon sequestration can be achieved. Summary of the Invention

[0004] In order to recycle geothermal energy and realize CO2 sequestration by recharging geothermal fluid, the present invention provides an integrated system for CO2 hybrid heating power generation and sequestration driven by geothermal energy.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] An integrated system for CO2 hybrid heating power generation and sequestration driven by geothermal energy, comprising a geothermal water circulation pump, a contact mixing heater, a liquid distribution pipe, a swirl chamber, an expander, a generator, and a condenser; wherein,

[0007] The geothermal water circulation pump is used to extract and transfer the hot water from the production well to the contact mixing heater. A liquid distribution pipe is arranged in the contact mixing heater, and the outlet end of the liquid distribution pipe is located inside the mixing heater. The liquid outlet end of the mixing heater is used to connect to the recharge well; the liquid distribution pipe is used to receive CO 2；

[0008] The cyclone chamber is connected to the top of the contact mixing heater. The liquid outlet of the cyclone chamber is connected to the bottom of the contact mixing heater. The top gas outlet of the cyclone chamber is connected to the inlet of the expander. The expander drives the generator to generate electricity. The outlet of the expander is connected to the inlet of the condenser. The outlet of the condenser is connected to the liquid distribution pipe.

[0009] Furthermore, a CO2 filling electric valve is installed in the pipeline connecting the inlet end of the liquid distribution pipe and the outlet of the condenser. The CO2 filling electric valve is connected to a CO2 gas source. A liquid level sensor is provided in the condenser to supplement the circulating working fluid CO2 by controlling the opening of the CO2 filling electric valve through the liquid level.

[0010] Furthermore, a CO2 booster pump is installed in the pipeline between the inlet end of the liquid distribution pipe and the CO2 filling electric valve.

[0011] Furthermore, a check valve is installed in the pipeline between the inlet end of the liquid distribution pipe and the CO2 booster pump.

[0012] Furthermore, a drain valve is installed in the pipeline between the liquid outlet of the cyclone chamber and the bottom of the contact mixing heater. Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] The integrated system for geothermal energy-driven CO2 hybrid heating power generation and storage provided in this embodiment has the circulating working fluid CO2 directly exchanging heat with the geothermal fluid through the liquid distribution pipe and the liquid outlet. Compared with the traditional indirect contact heat exchange, the heat transfer efficiency is greatly improved, the heat transfer area is greatly reduced, and the investment cost is reduced. At the same time, by utilizing the dissolution of CO2 in the geothermal fluid under high temperature and high pressure, it is backfilled into the injection well with the flow of the geothermal fluid, realizing the storage of CO2. Brief Description of the Drawings

[0014] Figure 1 It is a schematic diagram of the composition of the integrated system for geothermal energy-driven CO2 hybrid heating power generation and storage provided by the embodiment of the present invention;

[0015] In the figure: 1, production well; 2, geothermal water circulation pump; 3, contact mixing heater; 4, liquid distribution pipe; 5, liquid outlet; 6, cyclone chamber; 7, drain valve; 8, expander; 9, generator; 10, condenser; 11, liquid level sensor; 12, CO2 filling electric valve; 13, CO2 booster pump; 14, check valve; 15, injection well. Detailed Embodiments

[0016] Embodiment:

[0017] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the connection inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The technical solutions of the present invention will be further described below with reference to the drawings and embodiments.

[0018] Referring to Figure 1 As shown, the integrated system for geothermal energy-driven CO2 hybrid heating power generation and storage provided in this embodiment mainly includes a geothermal water circulation pump 2, a contact mixing heater 3, a liquid distribution pipe 4, a swirl chamber 6, an expander 8, a generator 9, and a condenser 10.

[0019] Among them, the geothermal water circulation pump 2 is used to extract and transfer the hot water from the production well 1 to the contact mixing heater 3. A liquid distribution pipe 4 is provided in the contact mixing heater 3, and the outlet end 5 of the liquid distribution pipe is located inside the mixing heater 3. The liquid outlet end of the mixing heater 3 is used to connect to the reinjection well 15, and the liquid distribution pipe 4 is used to receive CO2. In this way, the geothermal fluid in the production well 1 enters the contact and mixing heater 3 through the geothermal water circulation pump 2, and CO2 enters the inside of the contact mixing heater 3 through the liquid distribution pipe 4, directly mixes with the geothermal water, absorbs the heat of the geothermal energy, and becomes a high-temperature and high-pressure supercritical CO2 fluid. Part of the CO2 dissolves in the geothermal fluid and enters the reinjection well 15 with the reinjection of the geothermal water, realizing the storage of CO2.

[0020] The swirl chamber 6 is connected to the top of the contact mixing heater 3. The liquid outlet of the swirl chamber 6 is connected to the bottom of the contact mixing heater 3. The top gas outlet of the swirl chamber 6 is connected to the inlet of the expander 8. The expander 8 drives the generator 9 to generate electricity. The outlet of the expander 8 is connected to the inlet of the condenser 10, and the outlet of the condenser 10 is connected to the liquid distribution pipe 4. In this way, due to the carrying effect, the high-temperature and high-pressure supercritical CO2 fluid contains fine geothermal fluid droplets and enters the swirl chamber 6 for the separation of CO2 and geothermal fluid droplets. The separated pure high-temperature and high-pressure supercritical CO2 fluid enters the expander 8 to do work and drives the generator 9 to generate electricity. The separated geothermal fluid droplets enter the bottom of the swirl chamber 6 by gravity and then flow into the bottom of the contact mixing heater 3; the CO2 exhaust steam after driving the expander 8 to do work enters the condenser 10 for cooling and then enters the contact mixing heater 3 to complete the cycle.

[0021] It can be seen that for the integrated system of geothermal energy-driven CO2 hybrid heating power generation and storage provided in this embodiment, the circulating working fluid CO2 directly exchanges heat with geothermal fluid through the liquid distribution pipe and the liquid outlet. Compared with the traditional indirect contact heat exchange, the heat transfer efficiency is greatly improved, the heat transfer area is greatly reduced, and the investment cost is reduced. At the same time, by utilizing the dissolution of CO2 in geothermal fluid under high temperature and high pressure, CO2 is stored as the geothermal fluid flows back into the injection well.

[0022] As a preference of this embodiment, a CO2 filling electric valve 12 is connected and installed in the pipeline connecting the inlet end of the liquid distribution pipe 4 and the gas outlet of the condenser 10, and the CO2 filling electric valve 12 is connected to the CO2 gas source; a liquid level sensor 10 is provided in the condenser 10 to supplement the circulating working fluid CO2 by controlling the opening of the CO2 filling electric valve 12 through the liquid level. In this way, the automatic replenishment of CO2 working fluid can be achieved.

[0023] In addition, a CO2 booster pump 13 is installed in the pipeline between the inlet end of the liquid distribution pipe 4 and the CO2 filling electric valve 12 to enable CO2 to smoothly enter the contact mixing heater and fully contact with the geothermal fluid. Further, a check valve 14 is installed in the pipeline between the inlet end of the liquid distribution pipe 4 and the CO2 booster pump 13 to prevent the backflow of CO2.

[0024] In addition, a drain valve 7 is installed in the pipeline between the liquid outlet of the swirl chamber 6 and the bottom of the contact mixing heater 4.

[0025] The structure of the present invention is not limited to the structure shown in the drawings (embodiment). For example, the heat input of the system can also adopt the coupling form of geothermal energy and other low-grade heat energies; in addition to the water-cooled form, the condenser can also adopt the air-cooled form according to the actual situation. When different implementation methods are adopted, the system structure will change accordingly. Equivalent changes and improvements made according to the scope of the present invention application all fall within the protection scope of the present invention.

Claims

1. An integrated system for geothermal energy-driven CO2 hybrid heating, power generation and storage, characterized in that, It includes a geothermal water circulation pump, a contact mixing heater, a liquid distribution pipe, a swirl chamber, an expander, a generator, and a condenser; among them, the geothermal water circulation pump is used to extract and transfer the hot water from the production well to the contact mixing heater. A liquid distribution pipe is provided in the contact mixing heater, and the outlet end of the liquid distribution pipe is located inside the mixing heater. The liquid outlet end of the mixing heater is used to connect to the reinjection well, and the liquid distribution pipe is used to receive CO2; the swirl chamber is connected to the top of the contact mixing heater. The liquid outlet of the swirl chamber is connected to the bottom of the contact mixing heater. The top gas outlet of the swirl chamber is connected to the inlet of the expander. The expander drives the generator to generate electricity. The outlet of the expander is connected to the inlet of the condenser, and the outlet of the condenser is connected to the liquid distribution pipe.

2. The integrated system for geothermal energy-driven CO2 hybrid heating, power generation and storage according to claim 1, characterized in that, A CO2 filling electric valve is connected and installed in the pipeline where the inlet end of the liquid distribution pipe is communicated with the outlet of the condenser. The CO2 filling electric valve is connected to the CO2 gas source; a liquid level sensor is provided in the condenser to supplement the circulating working medium CO2 by controlling the opening of the CO2 filling electric valve through the liquid level.

3. The integrated system for geothermal energy-driven CO2 hybrid heating, power generation and storage according to claim 2, characterized in that, A CO2 booster pump is installed in the pipeline between the inlet end of the liquid distribution pipe and the CO2 filling electric valve.

4. The integrated system for geothermal energy-driven CO2 hybrid heating, power generation and storage according to claim 3, characterized in that, A one-way valve is installed in the pipeline between the inlet end of the liquid distribution pipe and the CO2 booster pump.

5. The integrated system for geothermal energy-driven CO2 hybrid heating, power generation and storage according to any one of claims 1-4, characterized in that, A drain valve is installed in the pipeline between the liquid outlet of the swirl chamber and the bottom of the contact mixing heater.

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