A geothermal power station system based on ORC system

Abstract

The present invention discloses a geothermal power plant system based on an ORC system, comprising a flash tank, a steam turbine, a first generator, a second generator, and an evaporator, a turbine, a condenser, a working fluid pump, and a preheater, which are sequentially connected through corresponding pipelines to form a loop. The second generator is connected to the turbine, and the evaporator is provided with at least two sets of evaporator tubes. The liquid outlet of the flash tank is connected to the inlet of one set of evaporator tubes through corresponding pipelines, the steam outlet of the flash tank is connected to the air inlet of the steam turbine through corresponding pipelines, and the exhaust outlet of the steam turbine is connected to the inlet of another set of evaporator tubes through corresponding pipelines. The steam turbine is also connected to the first generator. The outlets of the evaporator tubes are all connected to the tube inlet of the preheater through corresponding pipelines, and the tube outlet of the preheater is connected to the recharge pipe. The present invention not only has a simple structure and occupies a small area, but also has high heat exchange efficiency, low heat loss, and can fully utilize geothermal energy in a graded manner.

Description

Technical Field

[0001] The present invention belongs to the technical field of geothermal utilization and clean energy, and in particular relates to a geothermal power station system based on an ORC system. Background Art

[0002] The sustainable development of human society is constrained by energy shortages. Further strengthening energy conservation and emission reduction efforts and developing renewable energy are urgent solutions to address global energy shortages. The organic Rankine cycle (ORC) is a thermodynamic cycle that uses a low-boiling-point organic working fluid instead of water, the traditional Rankine cycle working fluid. It is particularly suitable for the development and utilization of medium- and low-temperature industrial waste heat, as well as medium- and low-grade renewable energy sources such as solar energy, biomass energy, and geothermal energy. ORC power generation technology not only has enormous economic value but also contributes to energy conservation, emission reduction, and environmental protection.

[0003] The Organic Rankine Cycle (ORC) uses low-boiling-point organic matter as the working fluid. It primarily consists of an evaporator, turbine, generator, condenser, and working fluid pump. In the evaporator, the organic working fluid absorbs heat from a low-temperature heat source (80-300°C), generating steam at a specific pressure and temperature. This steam enters the turbine, driving it to produce work, thereby driving the generator to generate high-quality electricity. The steam discharged from the turbine releases heat to an external cooling source in the condenser, condensing into a liquid. Finally, it is returned to the evaporator via the working fluid pump, completing the cycle.

[0004] Geothermal power plants utilize underground hot water, high-temperature rock, or steam as primary energy sources. Existing geothermal power plants have low energy utilization rates and complex structures. ORC geothermal power plants, however, can only utilize underground hot water and steam using different types of ORC units. This single-use approach fails to fully utilize the thermal energy in a tiered manner. Summary of the Invention

[0005] In order to solve the problems existing in the existing technology, the present invention aims to provide a geothermal power plant system based on the ORC system to fully utilize thermal energy.

[0006] In order to achieve the above technical objectives and effects, the present invention is implemented through the following technical solutions:

[0007] A geothermal power plant system based on an ORC system includes a flash tank, a steam turbine, a first generator, an evaporator, a turbine, a second generator, a condenser, a preheater, and a working fluid pump. The evaporator, the turbine, the condenser, the working fluid pump, and the preheater are sequentially connected via corresponding pipelines to form a loop. The second generator is connected to the turbine. The evaporator is provided with at least two groups of evaporator tubes. The liquid outlet of the flash tank is connected to one group of evaporator tube inlets via corresponding pipelines. The steam outlet of the flash tank is connected to the air inlet of the steam turbine via corresponding pipelines. The exhaust outlet of the steam turbine is connected to the other group of evaporator tube inlets via corresponding pipelines. The steam turbine is also connected to the first generator to provide power for the first generator. The outlets of the evaporator tubes are all connected to the tube inlets of the preheater via corresponding pipelines. The tube outlet of the preheater is connected to a recharge pipe. The evaporator tubes and the recharge pipe are connected via the tubes of the preheater.

[0008] Furthermore, the evaporator and the preheater are built into a cylinder.

[0009] Furthermore, the evaporator tubes are provided in two groups.

[0010] Furthermore, a common outlet is formed at the ends of the two groups of evaporator tubes, and the formed common outlet is connected to the tube inlet of the preheater through a corresponding pipeline.

[0011] Furthermore, the steam outlet of the flash tank is located at the top end of the flash tank, and the liquid outlet of the flash tank is located at the bottom end of the flash tank.

[0012] Furthermore, it also includes a filter for removing impurities in hot water in the geothermal well, and the filter is installed between the flash tank and the geothermal well through a corresponding pipeline.

[0013] Furthermore, a recovery pump is provided in the middle of the recharging pipe.

[0014] The beneficial effects of the present invention are as follows:

[0015] 1. The present invention installs a steam turbine at the gas phase outlet of the flash tank, using high-pressure steam to drive a generator for primary power generation. Low-pressure steam discharged from the steam turbine and hot water discharged from the liquid outlet of the flash tank are then transported to the tube side of the evaporator. The latent heat of the low-pressure steam and hot water is used to convert the working fluid in the evaporator shell side into a higher-pressure gas, thus achieving secondary power generation in the ORC system. This not only has a simple structure but also can fully utilize geothermal energy in a graded manner.

[0016] 2. The evaporator tube of the ORC power generation system of the present invention adopts a split-pass design, so that steam and hot water of different temperatures and pressures can enter the evaporator at the same time, thereby improving the heat exchange efficiency of the system and reducing heat loss;

[0017] 3. The evaporator and preheater in the ORC power generation system of the present invention are built into a cylinder, with an integrated design, which improves the heat exchange efficiency of the system, reduces the floor space and reduces the cost.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the description, the following preferred embodiments of the present invention are described in detail with reference to the accompanying drawings. The specific implementation methods of the present invention are given in detail by the following embodiments and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the common outlet connection of the evaporator tube pass of the present invention.

[0022] Explanation of the numbers in the figure: 1. Flash tank; 2. Steam turbine; 3. First generator; 4. Evaporator; 5. Turbine; 6. Second generator; 7. Condenser; 8. Preheater; 9. Working fluid pump; 10. Recharge pipe; 11. Filter; 12. Recovery pump; 13. Cylinder. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0024] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, upper end, lower end, top, bottom...) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0025] See also Figure 1As shown, a geothermal power plant system based on an ORC system includes a flash tank 1, a steam turbine 2, a first generator 3, an evaporator 4, a turbine 5, a second generator 6, a condenser 7, a preheater 8 and a working fluid pump 9. The evaporator 4, the turbine 5, the condenser 7, the working fluid pump 9 and the preheater 8 are sequentially connected through corresponding pipelines to form a loop. The second generator 6 is connected to the turbine 5. At least two groups of evaporator tubes are provided in the evaporator 4. The liquid outlet of the flash tank 1 is connected to a group of the evaporator tubes through corresponding pipelines. The steam outlet of the flash tank 1 is connected to the air inlet of the steam turbine 2 through a corresponding pipeline, and the exhaust port of the steam turbine 2 is connected to the inlet of another group of the evaporator tube side through a corresponding pipeline. The steam turbine 2 is also connected to the first generator 3 to provide power for the first generator 3; the outlets of the evaporator tube side are connected to the tube side inlet of the preheater 8 through corresponding pipelines, the tube side outlet of the preheater 8 is connected to the recharge pipe 10, and the evaporator tube side and the recharge pipe 10 are connected through the tube side of the preheater 8.

[0026] Among them, in the connection between the evaporator 4, the turbine 5, the second generator 6, the condenser 7, the preheater 8 and the working fluid pump 9, the outlet of the working fluid pump 9 is connected to the shell-side inlet of the preheater 8 through a corresponding pipeline, the shell-side outlet of the preheater 8 is connected to the shell-side inlet of the evaporator 4 through a corresponding pipeline, the shell-side outlet of the evaporator 4 is connected to the inlet of the turbine 5 through a corresponding pipeline, the outlet of the turbine 5 is connected to the inlet of the condenser 7, and the outlet of the condenser 7 is connected to the inlet of the working fluid pump 9 through a corresponding pipeline.

[0027] Furthermore, the evaporator 4 and the preheater 8 are built into a cylinder 13, and the integrated design improves the heat exchange efficiency of the system, reduces the floor space and reduces the cost.

[0028] Furthermore, the evaporator tubes are provided in at least two groups, the inlet of one group of the evaporator tubes is connected to the liquid outlet of the flash tank 1, and the inlet of the other group of the evaporator tubes is connected to the exhaust port of the turbine 2. The remaining evaporator tubes can be used as backup, which is convenient for connecting other heat sources to the system or when the evaporator tubes used in this system are damaged, the connected evaporator tubes can be directly replaced, thereby minimizing system interruption and improving the power generation efficiency of the system; in this embodiment, the evaporator tubes are provided in two groups.

[0029] The evaporator tube side of the evaporator 4 adopts a split-pass design, so that steam and liquid of different temperatures and pressures can enter the evaporator at the same time during operation, thereby improving the heat exchange efficiency of the system and reducing heat loss.

[0030] For further information, see Figure 2 As shown, a common outlet is formed at the ends of the two groups of evaporator tubes, and the formed common outlet is connected to the tube inlet of the preheater 8 through a corresponding pipeline.

[0031] For further information, see Figure 1 As shown, due to the reason that steam floats and liquid sinks, the steam outlet of the flash tank 1 is located at the top of the flash tank 1, and the liquid outlet of the flash tank 1 is located at the bottom of the flash tank 1, which facilitates the output of steam and liquid from the flash tank 1 to the next stage.

[0032] For further information, see Figure 1 As shown, a filter 11 for removing impurities from hot water in the geothermal well is also included. The filter 11 is installed between the flash tank 1 and the geothermal well through a corresponding pipeline. When working, the hot water transported from the geothermal well can be processed by the filter 11 to remove impurities in the geothermal water, thereby preventing the impurities in the geothermal water from affecting the normal operation of other equipment or even causing damage.

[0033] For further information, see Figure 1 As shown, a recovery pump 12 is provided in the middle of the reinjection pipe 10 to assist the steam and hot water flowing into the reinjection pipe 10 to flow back to the reinjection well.

[0034] The working principle of the present invention is as follows:

[0035] The geothermal well transports the hot water and steam in the geothermal well into the flash tank 1 through a transmission pipeline, and flash evaporation is carried out in the flash tank 1, the steam floats up, and the liquid sinks down, thereby realizing gas-liquid separation; higher-pressure steam will be formed at the upper end of the flash tank 1, and the steam will pass through the steam outlet at the upper end of the flash tank 1 and enter the steam turbine 2 along the pipeline, driving the steam turbine 2 to rotate, thereby driving the first generator 3, and then generating electricity, realizing the primary utilization of geothermal energy. After passing through the exhaust port of the steam turbine 2, the steam is converted from higher-pressure steam to low-pressure steam, and enters one group of evaporator tubes in the evaporator 4 along the pipeline; the hot water liquid sinking to the lower end of the flash tank 1 passes through the liquid outlet at the lower end of the flash tank 1 and enters another group of evaporator tubes in the evaporator 4 along the pipeline.

[0036] The low-pressure steam and hot water in the evaporator tube side of the evaporator 4 exchange heat with the organic working fluid in the shell side of the evaporator 4. After absorbing heat, the organic working fluid in the evaporator 4 is converted into a higher-pressure gas and output from the working fluid output port on the evaporator 4. It is transported into the turbine 5 through a pipeline and expands and works in the turbine 5, driving the second generator 6 to generate electricity, thereby realizing the conversion of low-grade thermal energy into high-grade electrical energy; the organic working fluid that has completed work in the turbine 5 enters the condenser 7 for condensation and liquefaction, and finally, under the action of the working fluid pump 9, re-enters the evaporator 4 through the preheater 8, and continues to exchange heat with the low-pressure steam and hot water in the evaporator tube side, thereby realizing uninterrupted power generation.

[0037] The hot water and steam that have been superheated with the organic working medium in the shell side of the evaporator 4 are transported into the recharge pipe 10 through the tube side of the preheater 8, and the superheated hot water and steam in the recharge pipe 10 are returned to the recharge well by the recovery pump 12; and the hot water and steam that have passed through the tube shell of the preheater 8 use the waste heat to preheat the organic working medium that has passed through the shell side of the preheater 8, so that the organic working medium that has entered the shell side of the evaporator 4 starts to absorb heat in advance, thereby improving the heat exchange efficiency of the entire system.

[0038] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A geothermal power plant system based on an ORC system, characterized by: The invention comprises a flash tank (1), a steam turbine (2), a first generator (3), an evaporator (4), a turbine (5), a second generator (6), a condenser (7), a preheater (8) and a working fluid pump (9), wherein the evaporator (4), the turbine (5), the condenser (7), the working fluid pump (9) and the preheater (8) are sequentially connected through corresponding pipelines to form a loop, the second generator (6) is connected to the turbine (5), and at least two groups of evaporator tubes are provided in the evaporator (4); the liquid outlet of the flash tank (1) is connected to the inlet of one group of the evaporator tubes through corresponding pipelines. The steam outlet of the flash tank (1) is connected to the air inlet of the steam turbine (2) through a corresponding pipeline, the exhaust port of the steam turbine (2) is connected to the inlet of another group of the evaporator tubes through a corresponding pipeline, and the steam turbine (2) is also connected to the first generator (3) to provide power for the first generator (3); the outlets of the evaporator tubes are connected to the tube inlet of the preheater (8) through corresponding pipelines, the tube outlet of the preheater (8) is connected to the recharge pipe (10), and the evaporator tubes and the recharge pipe (10) are connected through the tube of the preheater (8); The evaporator (4) and the preheater (8) are built into a cylinder (13); The evaporator tubes are provided in two groups; A common outlet is formed at the ends of the two groups of evaporator tubes, and the formed common outlet is connected to the tube inlet of the preheater (8) through a corresponding pipeline.

2. The geothermal power plant system based on the ORC system according to claim 1, characterized in that: The steam outlet of the flash tank (1) is located at the top end of the flash tank (1), and the liquid outlet of the flash tank (1) is located at the bottom end of the flash tank (1).

3. The geothermal power plant system based on the ORC system according to claim 1, characterized in that: It also includes a filter (11) for removing impurities from hot water in the geothermal well. The filter (11) is installed between the flash tank (1) and the geothermal well through a corresponding pipeline.

4. The geothermal power plant system based on the ORC system according to claim 1, characterized in that: A recovery pump (12) is provided in the middle of the recharging pipe (10).

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