Crude oil electric dehydration system utilizing geothermal energy and working method

Abstract

The invention relates to the technical field of oil and gas gathering and transportation systems, in particular to a crude oil electric dehydration system utilizing geothermal energy and a working method. The cold flow inlet side of an electric dehydrator is connected with a first heat exchanger, and the cold flow outlet side of the electric dehydrator is connected with a second heat exchanger; according to the terrestrial heat flash evaporation circulation system, the working medium inlet side of a flash evaporation tank is connected with terrestrial heat, the liquid phase outlet end of the flash evaporation tank is sequentially connected with a second heat exchanger and a first heat exchanger, and the gas phase outlet end of the flash evaporation tank is sequentially connected with a steam turbine expander and a third heat exchanger; according to the organic Rankine cycle system, the outlet side of an organic working medium pump is sequentially connected with a third heat exchanger, an organic Rankine turbo expander and a first heat exchanger, and the organic Rankine turbo expander supplies power to an electric dehydrator. By means of the device, preheating treatment and efficient oil-water separation can be rapidly and efficiently conducted on crude oil emulsion, and meanwhile direct recycling of heat energy and electric energy is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas gathering and transportation systems, and in particular to a crude oil electric dehydration system and a working method utilizing geothermal energy. Background Art

[0002] In the oil and gas gathering and transportation system, oil-water separation is a key link, which directly affects the quality of crude oil and the efficiency of subsequent processing. With the development of technology, people are constantly seeking more efficient and environmentally friendly oil-water separation technology.

[0003] Electric dehydration is an important oil-water separation technology widely used in oilfield surface gathering and transportation systems for treating crude oil emulsions. Its basic principle is to use the difference in electrical properties between oil and water phases through an external electric field to promote the migration, coalescence and sedimentation of water droplets in the oil, and finally achieve oil-water separation. However, the traditional crude oil electric dehydration system requires a large amount of electricity supply during operation, which leads to high energy consumption of the system and significantly increases the operating cost of oilfield surface projects; in addition, before entering the electric dehydration equipment, in order to improve the oil-water separation efficiency, the crude oil usually needs to be heated and pre-treated, which not only requires additional heating equipment and energy consumption, but also makes the operation process of the crude oil electric dehydration system complicated and the operation efficiency low.

[0004] Geothermal energy is an emerging renewable energy source with the advantages of low carbon dioxide emissions and being unaffected by weather and seasonal climate changes. It has good application prospects in the field of medium and low temperature heat supply and power generation. However, the heat and electricity produced by large-scale geothermal energy production systems cannot be used on-site and usually need to be exported to consumption locations, which leads to energy loss and increased facility construction and maintenance costs. Oilfield surface facilities, especially electric dehydration systems, usually require a large amount of energy supply, but existing geothermal energy production systems face some specific challenges when integrating. First, there is a difference between the output temperature of the existing system and the required temperature of the oilfield facilities, resulting in low energy conversion efficiency. Secondly, the traditional geothermal energy supply model is difficult to provide sufficient electricity and fails to fully meet the energy needs of crude oil electric dehydration, resulting in low overall energy utilization.

[0005] In summary, the current oilfield electric dehydration systems generally have defects such as high energy consumption, complex processes and high operating costs. The existing technology has not achieved effective integration of geothermal energy and oilfield electric dehydration, and it is difficult to solve the problem of insufficient energy utilization in the process of oil-water separation and geothermal energy consumption. Summary of the invention

[0006] In view of the deficiencies in the prior art, the purpose of the embodiments of the present invention is to provide a crude oil electric dehydration system and working method using geothermal energy, which combines the crude oil electric dehydration process, geothermal flash cycle and organic Rankine cycle, and can not only quickly and efficiently perform preheating treatment on crude oil emulsion and efficient oil-water separation, but also realize direct recovery and utilization of heat energy and electrical energy, and ensure sufficient and stable supply of geothermal energy and electricity; while solving the problem of complex and inefficient crude oil dehydration process, it greatly reduces the operation and maintenance costs of oilfield surface engineering; at the same time, the system makes cascade use of geothermal energy, cleverly realizes the matching of geothermal energy output temperature with electric dehydration demand temperature and effectively improves the thermal efficiency and power generation efficiency of the dehydration system; it has the advantages of reasonable and compact structure, safe and flexible control, high efficiency and energy saving, strong practicality and low cost.

[0007] In order to achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0008] A crude oil electric dehydration system utilizing geothermal energy comprises: a crude oil heating and separation system, comprising an electric dehydrator, wherein the cold flow inlet side of the electric dehydrator is connected to a first heat exchanger, and the cold flow outlet side is connected to a second heat exchanger; a geothermal flash circulation system, comprising a flash tank and a steam turbine expander, wherein the working fluid inlet side of the flash tank is connected to geothermal energy, the liquid phase outlet end of the flash tank is sequentially connected to the second heat exchanger and the first heat exchanger, and the gas phase outlet end of the flash tank is sequentially connected to the steam turbine expander and the third heat exchanger, and the steam turbine expander supplies power to the electric dehydrator; an organic Rankine cycle system, comprising an organic working fluid pump and an organic Rankine turbine expander, wherein the outlet side of the organic working fluid pump is sequentially connected to the third heat exchanger, the organic Rankine turbine expander and the first heat exchanger, and the organic Rankine turbine expander supplies power to the electric dehydrator.

[0009] The embodiment of the present invention also provides a working method of the crude oil electric dehydration system using geothermal energy as described above, comprising: the crude oil emulsion is sent to the first heat exchanger, and is heated by the geothermal water discharged from the second heat exchanger and the exhaust gas released by the organic Rankine turbine expander, and then, the crude oil is separated from the water by the electric dehydrator, and the separated dehydrated crude oil is heated in the second heat exchanger and enters the crude oil gathering and transportation network; the steam-water mixture extracted from the geothermal water well is sent to the flash tank for gas-liquid separation, and the liquid water is used to heat the dehydrated crude oil and the crude oil emulsion by the second heat exchanger and the first heat exchanger, and the separated steam is used to generate electricity to provide electricity for the electric dehydrator, and the exhaust gas is condensed by the third heat exchanger and then injected back into the ground to complete the geothermal cycle; the organic working fluid is heated and gasified in the third heat exchanger after being pressurized, and enters the organic Rankine turbine expander to generate electricity to provide electricity for the electric dehydrator, and the exhaust gas after power generation is cooled and liquefied in the first heat exchanger and enters the next cycle to form an organic Rankine cycle.

[0010] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0011] 1. The present invention skillfully combines the crude oil electric dehydration process, geothermal flash cycle and organic Rankine cycle, utilizes geothermal water to heat the dehydrated crude oil, increases the crude oil transmission temperature to reduce the crude oil pipeline resistance, and also utilizes the waste heat of geothermal water and organic working fluid exhaust gas to preheat the crude oil emulsion, significantly reduces the viscosity of the crude oil emulsion and the oil-water interface film strength, accelerates the coalescence and sedimentation of water droplets in the oil, and effectively improves the oil-water separation efficiency while simplifying the processing flow and reducing the operating cost; by integrating the electricity generated by geothermal steam expansion and the organic Rankine cycle to jointly supply the electric dehydrator, the energy consumption of crude oil dehydration is greatly reduced; geothermal water wells are used to collect medium and low temperature geothermal energy, and are used as a heat source to supply the geothermal flash cycle. After the heat-absorbing steam-water mixture is separated by flash evaporation, heat is provided for the dehydrated crude oil transmission heating, the crude oil emulsion preheating and the organic Rankine cycle, respectively, to achieve efficient utilization of geothermal energy.

[0012] 2. The present invention not only ensures the rapid pretreatment of crude oil emulsion and efficient oil-water separation, but also realizes self-sufficiency in electric energy; while solving the problem of complex and inefficient crude oil dehydration process, it greatly reduces the operation and maintenance costs of oil field surface projects; at the same time, it realizes the cascade utilization of geothermal energy, effectively improving the thermal efficiency and power generation efficiency of the system; it has the advantages of reasonable and compact structure, safe and flexible control, high efficiency and energy saving, strong practicality and low cost.

[0013] Advantages of additional aspects of the present invention will be given in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In addition, the spacing or size between each other is exaggerated to show the position of each part, and the schematic diagram is only used for illustration.

[0015] Figure 1 is a schematic diagram of a crude oil electric dehydration system using geothermal energy provided by an embodiment of the present invention;

[0016] In the figure: 1. Crude oil emulsion pump; 2. First heat exchanger; 3. Electric dehydrator; 4. Dehydrator power supply; 5. Second heat exchanger; 6. Geothermal water well; 7. Throttle valve; 8. Flash tank; 9. Steam turbine expander; 10. Third heat exchanger; 11. Geothermal pump; 12. Mixer; 13. Recharge well; 14. Organic working fluid pump; 15. Organic Rankine turbine expander. DETAILED DESCRIPTION

[0017] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0018] Example 1

[0019] like Figure 1 As shown, this embodiment discloses a crude oil electric dehydration system using geothermal energy, and the main components of the system include a crude oil heating and separation system, a geothermal flash circulation system, and an organic Rankine cycle system. Among them, the electric dehydrator 3 included in the crude oil heating and separation system is connected to the first heat exchanger 2 through the cold flow inlet side, so that the crude oil emulsion can be heated and effectively separated from oil and water. The cold flow outlet side is connected to the second heat exchanger 5 to further increase the temperature of the dehydrated crude oil and reduce its viscosity, thereby reducing pipeline resistance and improving transportation efficiency. In the geothermal flash circulation system, the working fluid inlet side of the flash tank 8 is connected to the geothermal resource, the liquid phase outlet end is heated by the second heat exchanger 5 and the first heat exchanger 2 to heat the dehydrated crude oil and crude oil emulsion, and the gas phase outlet end is connected to the steam turbine expander 9, and the electric energy generated by steam expansion is used to power the electric dehydrator 3, ensuring the energy self-sufficiency of the system. In addition, in the organic Rankine cycle system, the organic working fluid pump 14 transports the working fluid to the third heat exchanger 10 and the organic Rankine turbine expander 15, completing the heat energy conversion and providing additional electric energy for the electric dehydrator 3. This overall architecture design effectively integrates the recycling of heat energy and electric energy, and improves the overall energy efficiency of the system.

[0020] The crude oil heating and separation system also includes a crude oil emulsion pump 1, which plays the role of lifting and conveying the crude oil emulsion. The working fluid outlet side of the pump is connected to the cold flow inlet side of the first heat exchanger 2, ensuring that the crude oil emulsion can quickly reach the required temperature when entering the first heat exchanger 2. At the same time, the cold flow outlet side of the first heat exchanger 2 is connected to the liquid inlet of the electric dehydrator 3, so that the crude oil emulsion that has been preheated can effectively enter the horizontal electric dehydrator 3 for further separation. The oil outlet of the horizontal electric dehydrator 3 is connected to the cold flow inlet side of the second heat exchanger 5, realizing the subsequent heating treatment of the dehydrated crude oil separated from the crude oil emulsion. Through this design, the first heat exchanger 2 uses the geothermal flash cycle system and the organic Rankine cycle system to preheat the crude oil emulsion, and the second heat exchanger 5 uses the geothermal flash cycle system to increase the transportation temperature of the dehydrated crude oil, and uses the geothermal flash cycle system and the organic Rankine cycle system to simultaneously power the electric dehydrator 3 to promote the efficiency of oil-water separation. This integrated heating and separation solution greatly improves the transportation efficiency of crude oil and effectively simplifies the dehydration process.

[0021] The cold flow outlet side of the second heat exchanger 5 is connected to the crude oil gathering and transportation network, while the water outlet of the electric dehydrator 3 is connected to the sewage treatment station. This configuration enables the dehydrated crude oil to be quickly sent to the gathering and transportation network for transportation, and the generated oily sewage is sent to the sewage treatment station in time, avoiding environmental pollution. By rationally allocating the fluids at different outlets, resource utilization is optimized, ensuring the compliance and efficiency of the system in terms of environmental protection, thereby promoting a balance between economic benefits and environmental protection.

[0022] In the geothermal flash circulation system, the liquid phase outlet end of the flash tank 8 is connected to the heat flow inlet side of the second heat exchanger 5, and the heat flow outlet side of the second heat exchanger 5 is connected to the heat flow inlet side of the first heat exchanger 2. This flow path design allows the geothermal water to undergo gas-liquid separation in the flash tank 8, and the generated liquid water is used to provide heat for the dehydration process, which effectively improves the thermal energy utilization efficiency of the system. At the same time, the gas phase outlet end of the flash tank 8 is connected to the steam turbine expander 9 to ensure that the steam can be effectively used to generate electricity, thereby providing electricity for the entire electric dehydrator 3. This layered design not only improves the heat exchange efficiency of the system, but also realizes the optimal utilization of energy obtained from geothermal resources, improving the economy and sustainability of the overall operation.

[0023] Furthermore, the geothermal flash circulation system also includes a geothermal water well 6, a throttle valve 7 and a geothermal heat pump 11, etc. The outlet side of the geothermal water well 6 is connected to the inlet side of the throttle valve 7, and the outlet side of the throttle valve 7 is connected to the working medium inlet side of the flash tank 8. This configuration allows the high-temperature water obtained from the geothermal water well 6 to enter the flash tank 8 through the throttle valve 7 for treatment, thereby achieving effective utilization of high-temperature water. At the same time, the hot flow outlet side of the third heat exchanger 10 is connected to the geothermal heat pump 11. This design not only optimizes the utilization efficiency of geothermal energy, but also provides a stable heat source for the entire crude oil dehydration system, ensuring the reliability and flexibility of the system under different working conditions.

[0024] The geothermal flash circulation system also includes a mixer 12 and a reinjection well 13. The top heat flow outlet side of the first heat exchanger 2 is connected to one inlet end of the mixer 12, and the outlet side of the geothermal pump 11 is connected to the other inlet end of the mixer 12. The outlet end of the mixer 12 leads to the reinjection well 13. This configuration allows the fluids after heat exchange to be mixed and reinjected, effectively realizing the cascade utilization of geothermal energy. Through the design of the reinjection well 13, geothermal water can be recycled, reducing the waste of geothermal energy and ensuring the sustainable development of the system. This closed-loop system design concept enhances the overall environmental performance of the system.

[0025] In the organic Rankine cycle system, the outlet side of the organic working fluid pump 14 is connected to the cold flow inlet side of the third heat exchanger 10, and the cold flow outlet side of the third heat exchanger 10 is connected to the inlet side of the organic Rankine turbine expander 15. This configuration allows the organic working fluid to absorb enough heat to complete gasification when passing through the third heat exchanger 10, and enter the turbine expander to generate electricity, providing electrical energy for the electric dehydrator 3. At the same time, the outlet side of the organic Rankine turbine expander 15 is connected to the hot flow inlet side of the first heat exchanger 2. Through this design, the generated exhaust gas can effectively recover heat for heating the crude oil emulsion that is about to enter the system. This efficient heat and power recovery design not only improves the energy efficiency ratio of the system, but also ensures self-sufficiency in power supply.

[0026] The working fluid in the organic Rankine cycle system can include a variety of commonly used organic working fluids, including but not limited to R245fa pentafluoropropane, R365mfc pentafluorobutane, n-Nonane n-nonane, n-Octane n-octane or n-Pentane n-pentane. These working fluids have good thermal conductivity and gasification capabilities, and can effectively convert heat energy at lower temperatures. By selecting a suitable working fluid, the stability and economy of the organic Rankine cycle can be ensured, so that the overall system can maintain efficient operation under different working conditions. The specific working fluid selection can be adjusted according to the actual operating conditions and economy to achieve optimal thermal efficiency and power output.

[0027] In this system, the working fluid inlet side of the crude oil emulsion pump 1 is crude oil emulsion, and its water content is not more than 30% by mass fraction, which ensures the control of the water content of the crude oil before entering the electric dehydrator 3, and helps to improve the subsequent separation efficiency. The working fluid of the oil outlet of the electric dehydrator 3 is dehydrated crude oil, and its water content is less than or equal to 0.5% by mass fraction, which ensures the quality of the final product. The working fluid of the water outlet of the electric dehydrator 3 is oily wastewater, and the oil content is not more than 1000mg / L, which meets the environmental protection standards. The setting of these parameters ensures the safety and environmental protection of the system during operation, so that each link of the crude oil dehydration process can meet the expected technical effects.

[0028] The following is combined with Figure 1 A complete description of the entire system:

[0029] A crude oil electric dehydration system using geothermal energy, comprising a crude oil heating and separation system, a geothermal flash circulation system and an organic Rankine cycle system;

[0030] The crude oil heating and separation system includes a crude oil emulsion pump 1, the working fluid outlet side of the crude oil emulsion pump 1 is connected to the cold flow inlet side of the first heat exchanger 2, the cold flow outlet side of the first heat exchanger 2 is connected to the liquid inlet I of the horizontal electric dehydrator 3, and the oil outlet II of the horizontal electric dehydrator 3 is connected to the cold flow inlet side of the second heat exchanger 5.

[0031] The geothermal flash circulation system includes a geothermal water well 6, the outlet side of the geothermal water well 6 is connected to the inlet side of the throttle valve 7, the outlet side of the throttle valve 7 is connected to the working medium inlet side of the flash tank 8, the liquid phase outlet end of the flash tank 8 is connected to the heat flow inlet side of the second heat exchanger 5, the heat flow outlet side of the second heat exchanger 5 is connected to the top heat flow inlet side of the first heat exchanger 2, the top heat flow outlet side of the first heat exchanger 2 is connected to an inlet end of the mixer 12, the gas phase outlet end of the flash tank 8 is connected to the inlet side of the steam turbine expander 9, the electric energy generated by the steam turbine expander 9 is supplied to the dehydrator power supply 4, the outlet side of the steam turbine expander 9 is connected to the heat flow inlet side of the third heat exchanger 10, the heat flow outlet side of the third heat exchanger 10 is connected to the inlet side of the geothermal pump 11, the outlet side of the geothermal pump 11 is connected to the other inlet end of the mixer 12, and the outlet end of the mixer 12 is connected to the reinjection well 13.

[0032] The organic Rankine cycle system includes an organic working fluid pump 14, the outlet side of the organic working fluid pump 14 is connected to the cold flow inlet side of the third heat exchanger 10, the cold flow outlet side of the third heat exchanger 10 is connected to the inlet side of the organic Rankine turbine expander 15, the electric energy generated by the organic Rankine turbine expander 15 is supplied to the dehydrator power supply 4, the outlet side of the organic Rankine turbine expander 15 is connected to the bottom hot flow inlet side of the first heat exchanger 2, and the bottom hot flow outlet side of the first heat exchanger 2 is connected to the inlet side of the organic working fluid pump 14.

[0033] The crude oil heating and separation system is used to reduce the viscosity and interfacial film strength of dehydrated crude oil and crude oil emulsion, and promote oil-water separation and external transmission; the geothermal flash circulation system is used to provide multi-temperature heat sources for each system; the organic Rankine cycle system is used for medium and low temperature power generation; the present invention not only ensures the rapid pretreatment of crude oil emulsion and efficient oil-water separation, but also realizes self-sufficiency in electrical energy. While solving the problem of complex and inefficient crude oil dehydration process, it greatly reduces the operation and maintenance costs of oilfield surface engineering, and also realizes the cascade utilization of geothermal energy, effectively improving the thermal efficiency and power generation efficiency of the system, and has the advantages of reasonable and compact structure, safe and flexible control, high efficiency and energy saving, strong practicality and low cost.

[0034] Example 2

[0035] Based on the working method of a crude oil electric dehydration system using geothermal energy in Example 1, the specific steps include sending the crude oil emulsion into the first heat exchanger 2, and preheating it using the geothermal water discharged from the second heat exchanger 5 and the exhaust gas released by the organic Rankine turbine expander 15. The heated crude oil emulsion then enters the electric dehydrator 3 for oil-water separation, and the separated dehydrated crude oil is heated again in the second heat exchanger 5 and enters the crude oil gathering and transportation network to complete the efficient transportation of crude oil.

[0036] The steam-water mixture extracted from the geothermal water well 6 is sent to the flash tank 8 for gas-liquid separation. The liquid water uses the second heat exchanger 5 and the first heat exchanger 2 to heat the dehydrated crude oil and crude oil emulsion. The separated steam is used to generate electricity and supply electricity to the electric dehydrator 3, ensuring energy self-sufficiency of the entire process. The exhaust gas is condensed by the third heat exchanger 10 and then injected back into the ground to complete the geothermal cycle.

[0037] After being pressurized, the organic working fluid is heated and gasified by the third heat exchanger 10, and enters the organic Rankine turbine expander 15 to generate electricity, which again provides electricity for the electric dehydrator 3, while the exhaust gas after power generation is cooled and liquefied in the first heat exchanger 2, and enters the next cycle to form an organic Rankine cycle. This series of steps ensures the efficient and stable operation of the entire system, fully utilizes geothermal energy and electrical energy, and improves the efficiency of oil-water separation.

[0038] Specifically:

[0039] The crude oil emulsion extracted from the oil well is pressurized and transported to the first heat exchanger 2 by the crude oil emulsion pump 1, and then heated by the geothermal water discharged from the second heat exchanger 5 and the organic working fluid exhaust gas released by the organic Rankine turbine expander 15. The viscosity of the heated crude oil emulsion and the strength of the oil-water interface film are greatly reduced, and then it enters the horizontal electric dehydrator 3 through the liquid inlet I for efficient oil-water separation. The dehydrated crude oil separated from the crude oil emulsion is discharged from the oil outlet II, and is heated by geothermal water in the second heat exchanger 5 to reduce viscosity, and then passes into the crude oil gathering and transportation network to complete the crude oil heating and separation process.

[0040] The steam-water mixture extracted from the geothermal water well 6 is sent to the flash tank 8 for gas-liquid separation. The separated liquid water is used to heat the dehydrated crude oil and the crude oil emulsion in the second heat exchanger 5 and the first heat exchanger 2 respectively. The separated steam enters the steam turbine expander 9 to expand and generate power. The generated electric energy is directly supplied to the dehydrator power supply 4 to ensure the continuous and efficient operation of the horizontal electric dehydrator 3. The exhaust gas is condensed by the organic working fluid in the third heat exchanger 10, and then pressurized by the geothermal pump 11 and mixed with the water discharged from the first heat exchanger 2 in the mixer 12, and is transported to the reinjection well 13 and returned to the underground to complete the geothermal flash evaporation cycle.

[0041] After being pressurized by the organic working fluid pump 14, the organic working fluid is heated and gasified by steam exhaust gas in the third heat exchanger 10, and then enters the organic Rankine turbine expander 15 to expand and generate power. The generated electric energy is also supplied to the dehydrator power supply 4, ensuring the continuous and efficient separation of oil and water in the horizontal electric dehydrator 3. After completing the power generation process, the organic working fluid exhaust gas is cooled and liquefied by the crude oil emulsion in the first heat exchanger 2 and enters the next cycle, completing the organic Rankine cycle.

[0042] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A crude oil electric dehydration system using geothermal energy, characterized in that: include: The crude oil heating and separation system comprises an electric dehydrator, wherein the cold flow inlet side of the electric dehydrator is connected to a first heat exchanger, and the cold flow outlet side of the electric dehydrator is connected to a second heat exchanger; A geothermal flash circulation system comprises a flash tank and a steam turbine expander, wherein the working medium inlet side of the flash tank is connected to the geothermal, the liquid phase outlet end of the flash tank is connected to the second heat exchanger and the first heat exchanger in sequence, the gas phase outlet end of the flash tank is connected to the steam turbine expander and the third heat exchanger in sequence, and the steam turbine expander supplies power to the electric dehydrator; The organic Rankine cycle system comprises an organic working fluid pump and an organic Rankine turbine expander. The outlet side of the organic working fluid pump is sequentially connected to the third heat exchanger, the organic Rankine turbine expander and the first heat exchanger. The organic Rankine turbine expander supplies power to the electric dehydrator.

2. The crude oil electric dehydration system using geothermal energy according to claim 1, characterized in that: The crude oil heating and separation system also includes a crude oil emulsion pump, the working fluid outlet side of the crude oil emulsion pump is connected to the cold flow inlet side of the first heat exchanger, the cold flow outlet side of the first heat exchanger is connected to the liquid inlet of the electric dehydrator, and the oil outlet of the horizontal electric dehydrator is connected to the cold flow inlet side of the second heat exchanger.

3. The crude oil electric dehydration system using geothermal energy as claimed in claim 2, characterized in that: The cold flow outlet side of the second heat exchanger is connected to the crude oil gathering and transportation pipeline network, and the water outlet of the electric dehydrator is connected to a sewage treatment station.

4. The crude oil electric dehydration system using geothermal energy according to claim 1, characterized in that: In the geothermal flash circulation system, the liquid phase outlet end of the flash tank is connected to the heat flow inlet side of the second heat exchanger, and the heat flow outlet side of the second heat exchanger is connected to the heat flow inlet side of the first heat exchanger; the gas phase outlet end of the flash tank is connected to the inlet side of the steam turbine expander, and the outlet side of the steam turbine expander is connected to the heat flow inlet side of the third heat exchanger.

5. The crude oil electric dehydration system using geothermal energy as claimed in claim 4, characterized in that: The geothermal flash circulation system also includes a geothermal water well, a throttle valve and a geothermal pump. The outlet side of the geothermal water well is connected to the inlet side of the throttle valve, the outlet side of the throttle valve is connected to the working medium inlet side of the flash tank, and the hot flow outlet side of the third heat exchanger is connected to the inlet side of the geothermal pump.

6. The crude oil electric dehydration system using geothermal energy as claimed in claim 5, characterized in that: The geothermal flash circulation system also includes a mixer and a reinjection well. The top heat flow outlet side of the first heat exchanger is connected to one inlet end of the mixer, the outlet side of the geothermal pump is connected to the other inlet end of the mixer, and the outlet end of the mixer leads to the reinjection well.

7. The crude oil electric dehydration system using geothermal energy according to claim 1, characterized in that: In the organic Rankine cycle system, the outlet side of the organic working fluid pump is connected to the cold flow inlet side of the third heat exchanger, the cold flow outlet side of the third heat exchanger is connected to the inlet side of the organic Rankine turbine expander, the organic Rankine turbine expander supplies power to the electric dehydrator, the outlet side of the organic Rankine turbine expander is connected to the hot flow inlet side of the first heat exchanger, and the hot flow outlet side of the first heat exchanger is connected to the inlet side of the organic working fluid pump.

8. The crude oil electric dehydration system using geothermal energy as claimed in claim 7, characterized in that: The working fluid in the organic Rankine cycle system includes R245fa pentafluoropropane, R365mfc pentafluorobutane, n-Nonane, n-Octane or n-Pentane.

9. The crude oil electric dehydration system using geothermal energy as claimed in claim 2, characterized in that: The working fluid at the working fluid inlet side of the crude oil emulsion pump is crude oil emulsion, and the mass fraction of water content is not more than 30%; the working fluid at the oil outlet of the electric dehydrator is dehydrated crude oil, and the mass fraction of water content is less than or equal to 0.5%; the working fluid at the water outlet of the electric dehydrator is oily wastewater, and the oil content is not more than 1000 mg / L.

10. A method for operating a crude oil electric dehydration system using geothermal energy according to any one of claims 1 to 9, characterized in that: include: The crude oil emulsion is sent to the first heat exchanger and heated by the geothermal water discharged from the second heat exchanger and the exhaust gas released by the organic Rankine turbine expander. Then, it is separated into oil and water by the electric dehydrator. The separated dehydrated crude oil is heated in the second heat exchanger and then enters the crude oil gathering and transportation network. The steam-water mixture extracted from the geothermal water well is sent to the flash tank for gas-liquid separation. The liquid water is used to heat the dehydrated crude oil and crude oil emulsion using the second heat exchanger and the first heat exchanger. The separated steam is used to generate electricity to provide power for the electric dehydrator. The exhaust gas is condensed by the third heat exchanger and then injected back into the ground to complete the geothermal cycle. The organic working fluid is heated and gasified in the third heat exchanger after being pressurized, and enters the organic Rankine turbine expander to generate electricity to provide electricity for the electric dehydrator. The exhaust gas after power generation is cooled and liquefied in the first heat exchanger and enters the next cycle, forming an organic Rankine cycle.

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