Supercritical carbon dioxide isothermal compression system

Abstract

An embodiment of the present invention provides a supercritical carbon dioxide isothermal compression system, comprising: a compressor having a compression inlet and a compression outlet; a mixer connected to the compressor and communicating with the compression inlet, the mixer being used to mix carbon dioxide and oil; and a separator communicating with the compression outlet, the separator being used to separate the mixture of carbon dioxide and oil. In this supercritical carbon dioxide isothermal compression system, the mixer mixes gaseous supercritical carbon dioxide and liquid oil to form a gas-liquid mixture. This gas-liquid mixture is compressed under the action of the compressor. The gaseous supercritical carbon dioxide generates a large amount of heat of compression during compression, while the liquid oil, with its high specific heat, absorbs the heat of compression generated by the supercritical carbon dioxide, thereby suppressing the temperature rise of the supercritical carbon dioxide during compression, reducing the compression work generated during compression, and reducing the energy consumed during compression.

Description

Technical Field

[0001] The embodiments of the present invention belong to the field of compression system technology, specifically relating to a supercritical carbon dioxide isothermal compression system. Background Technology

[0002] Supercritical carbon dioxide cycle power generation systems are currently the most promising thermal power generation cycle systems, possessing advantages such as high efficiency and system simplicity. The core of the high efficiency of supercritical carbon dioxide cycles lies in the low compression work of the cycle; therefore, isothermal compression of near-critical carbon dioxide media is an effective way to further improve the efficiency of supercritical carbon dioxide cycle power generation systems.

[0003] Currently, there are no isothermal compressors available that meet the requirements, therefore, there is an urgent need for a compression system that can provide isothermal operation. Summary of the Invention

[0004] The embodiments of the present invention aim to at least solve one of the technical problems existing in the prior art, and provide a supercritical carbon dioxide isothermal compression system.

[0005] An embodiment of the present invention provides a supercritical carbon dioxide isothermal compression system, the supercritical carbon dioxide isothermal compression system comprising: a compressor having a compression inlet and a compression outlet;

[0006] A mixer connected to the compressor and in communication with the compression inlet, the mixer being used to mix carbon dioxide and oil;

[0007] A separator, connected to the compression outlet, is used to separate a mixture of carbon dioxide and oil.

[0008] In some embodiments of the present invention, the mixer has a mixing air inlet and a mixing liquid inlet, the mixing air inlet being used to introduce carbon dioxide, and the mixing liquid inlet being provided with a nozzle for introducing oil.

[0009] In some embodiments of the present invention, the supercritical carbon dioxide isothermal compression system further includes:

[0010] The oil tank has an oil tank outlet that is connected to the nozzle, and the oil tank is used to supply oil to the nozzle.

[0011] In some embodiments of the present invention, the oil tank and the nozzle are connected by a connecting pipeline, and a high-pressure pump is provided on the connecting pipeline.

[0012] In some embodiments of the present invention, an oil quantity regulating valve is provided on the connecting pipeline, and the oil quantity regulating valve is located between the high-pressure pump and the nozzle.

[0013] In some embodiments of the present invention, the separator has a separation outlet, the oil tank has an oil tank inlet, and the separation outlet is connected to the oil tank inlet.

[0014] In some embodiments of the present invention, the supercritical carbon dioxide isothermal compression system further includes:

[0015] A turbine, wherein the turbine has a turbine inlet and a turbine outlet, the separation outlet is connected to the turbine inlet, and the turbine outlet is connected to the oil tank inlet.

[0016] In some embodiments of the present invention, the supercritical carbon dioxide isothermal compression system further includes:

[0017] A cooler having a cooling inlet and a cooling outlet, the cooling inlet being connected to the turbine outlet and the cooling outlet being connected to the oil tank inlet.

[0018] In some embodiments of the present invention, the main shaft of the turbine is coaxially connected with the main shaft of the compressor.

[0019] In some embodiments of the present invention, the supercritical carbon dioxide isothermal compression system further includes:

[0020] A pressure stabilizing tank is connected to the mixing inlet of the mixer, and the pressure stabilizing tank is used to provide the mixer with pressure-stabilized carbon dioxide.

[0021] In the supercritical carbon dioxide isothermal compression system of this invention, the compressor inlet is equipped with a mixer and the compressor outlet is equipped with a separator. The mixer mixes gaseous supercritical carbon dioxide and liquid oil to form a gas-liquid mixture. The gas-liquid mixture enters the compressor through the compressor inlet and is compressed under the action of the compressor. The gaseous supercritical carbon dioxide generates a large amount of heat of compression during compression. The liquid oil has a high specific heat and can absorb the heat of compression generated by the supercritical carbon dioxide, thereby suppressing the temperature rise of the supercritical carbon dioxide during compression and keeping the temperature of the supercritical carbon dioxide gas constant during compression. At the same time, it reduces the compression work generated during compression, that is, reduces the energy consumed during compression. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a supercritical carbon dioxide isothermal compression system according to an embodiment of the present invention.

[0023] The labels in the attached diagram are as follows:

[0024] 100. Supercritical carbon dioxide power generation isothermal compression system;

[0025] 1. Compressor; 2. Mixer; 3. Nozzle; 4. Pressure stabilizing tank; 5. Separator; 6. Cooler; 7. Oil tank; 8. High-pressure pump; 9. Oil quantity regulating valve; 10. Liquid level regulating valve; 11. Turbine spindle; 12. Turbine; 13. Connecting pipelines. Detailed Implementation

[0026] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0027] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0028] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0029] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0030] like Figure 1 As shown, an embodiment of the present invention provides a supercritical carbon dioxide isothermal compression system. The supercritical carbon dioxide isothermal compression system includes: a compressor 1, a mixer 2, and a separator 5. Specifically, the compressor 1 has a compression inlet and a compression outlet. The mixer 2 is connected to the compressor 1 and communicates with the compression inlet. The mixer 2 is used to mix carbon dioxide and oil. The separator 5 is communicated with the compression outlet and is used to separate the mixture of carbon dioxide and oil.

[0031] In the supercritical carbon dioxide isothermal compression system of this invention, the compressor 1 is equipped with a mixer 2 at the compression inlet and a separator 5 at the compression outlet. The mixer 2 mixes gaseous supercritical carbon dioxide and liquid oil to form a gas-liquid mixture. The gas-liquid mixture enters the compressor 1 through the compression inlet and is compressed under the action of the compressor 1. The gaseous supercritical carbon dioxide generates a large amount of compression heat during compression. The liquid oil has a high specific heat and can absorb the compression heat generated by the supercritical carbon dioxide, thereby suppressing the temperature rise of the supercritical carbon dioxide during compression and keeping the temperature of the supercritical carbon dioxide gas constant during compression. At the same time, it reduces the compression work generated during compression, that is, reduces the energy consumed during compression.

[0032] Specifically, the compressor 1 in this invention can be a centrifugal compressor 1 or an axial compressor 1, and is generally driven by an electric motor. Driving a centrifugal compressor or an axial compressor 1 with an electric motor can achieve a two-phase gas-liquid mixture of supercritical carbon dioxide and oil.

[0033] The oil used in this invention can be a suitable industrial refrigeration oil for carbon dioxide media, such as a polyether-based synthetic refrigeration oil. The density of the refrigeration oil is slightly greater than the density of the supercritical carbon dioxide input into the mixer 2, allowing the refrigeration oil to mix thoroughly with gaseous carbon dioxide to form a gas-liquid mixture. Because the density of the refrigeration oil is slightly greater than that of carbon dioxide, the refrigeration oil and carbon dioxide are compressed and then input into the separator 5. Under the action of the separator 5, the refrigeration oil and gaseous carbon dioxide are separated. The refrigeration oil is discharged from the separator 5 through the liquid outlet at the bottom, and the gaseous carbon dioxide is discharged from the separator 5 through the gas outlet at the top.

[0034] In some embodiments of the present invention, the mixer 2 has a mixing inlet for air and a mixing inlet for liquid. The mixing inlet for air is used to introduce carbon dioxide, and the mixing inlet for liquid is provided with a nozzle 3 for introducing oil. Specifically, carbon dioxide enters the mixer 2 through the mixing inlet, and oil enters the mixer 2 through the nozzle 3. The nozzle 3 sprays the oil into the mixer 2, causing the oil to form small droplets or mist. The small droplet-shaped oil or mist can be fully mixed with gaseous carbon dioxide to form a uniform gas-liquid mixture of oil and carbon dioxide. When the gas-liquid mixture of oil and carbon dioxide enters the compressor 1 through the compressor 1 inlet, the compressor 1 compresses the gas-liquid mixture of oil and carbon dioxide. Because the small droplet-shaped oil or mist is fully mixed with the gaseous carbon dioxide, the oil can fully and uniformly absorb the heat of compression generated during the compression of gaseous carbon dioxide, ensuring that the temperature of carbon dioxide remains constant during the compression process.

[0035] In some embodiments of the present invention, the supercritical carbon dioxide isothermal compression system further includes a pressure stabilizing tank 4, which is connected to the mixing inlet of the mixer 2. The pressure stabilizing tank 4 is used to provide pressure-stabilized carbon dioxide to the mixer 2. Specifically, the pressure stabilizing tank 4 has a pressure-stabilizing inlet and a pressure-stabilizing outlet. The carbon dioxide supply device inputs carbon dioxide into the pressure stabilizing tank 4 through the pressure-stabilizing inlet to ensure that a stable pressure of carbon dioxide is formed inside the pressure stabilizing tank 4. The pressure stabilizing tank 4 inputs carbon dioxide at a certain pressure into the mixer 2 through the mixing inlet via the pressure-stabilizing outlet, so that the gaseous carbon dioxide and oil are fully mixed in the mixer 2.

[0036] In some embodiments of the present invention, the supercritical carbon dioxide isothermal compression system further includes: an oil tank 7, which has an oil tank outlet connected to a nozzle 3, and the oil tank 7 is used to supply oil to the nozzle 3. Specifically, the oil in the oil tank 7 is discharged from the oil tank 7 through the oil tank outlet and then sprayed into the mixer 2 through the nozzle 3 to fully mix the small liquid oil or mist oil with the gaseous carbon dioxide.

[0037] In some embodiments of the present invention, the oil tank 7 and the nozzle 3 are connected by a connecting pipe 13, and a high-pressure pump 8 is provided on the connecting pipe 13. Specifically, under the action of the high-pressure pump 8, the oil in the oil tank 7 is discharged from the oil tank 7 through the oil tank outlet, and then enters the connecting pipe 13 connected to the outlet, and finally enters the nozzle 3 through the connecting pipe 13 to ensure sufficient oil supply in the mixer 2.

[0038] In some embodiments of the present invention, an oil quantity regulating valve 9 is provided on the connecting pipeline 13, and the oil quantity regulating valve 9 is located between the high-pressure pump 8 and the nozzle 3. The oil quantity entering the mixer 2 can be adjusted by regulating the valve to control the mixing ratio of oil and gaseous carbon dioxide in the mixer 2, so as to ensure that the oil and gaseous carbon dioxide are fully mixed.

[0039] In some embodiments of the present invention, the separator 5 has a liquid outlet, and the oil tank 7 has an oil tank inlet, with the liquid outlet communicating with the oil tank inlet. Specifically, the separator 5 separates the compressed oil and gaseous carbon dioxide mixture into compressed gaseous carbon dioxide and compressed liquid oil. The gaseous carbon dioxide exits the separator 5 from the liquid outlet and is transported to other devices, while the liquid oil is transported through the liquid outlet to the oil tank inlet and enters the oil tank 7. Under the action of the high-pressure pump 8, the oil in the oil tank 7 first enters the connecting pipe 13 through the oil tank outlet, and then enters the nozzle 3 through the connecting pipe 13. The oil is then sprayed into the mixer 2 through the nozzle 3. In the mixer 2, the oil mixes with gaseous carbon dioxide to form a gas-liquid mixture. After being compressed, the gas-liquid mixture is transported to the separator 5. The separator 5 separates the compressed oil and carbon dioxide gas-liquid mixture into gaseous carbon dioxide and liquid oil. The liquid oil enters the oil tank inlet of the oil tank 7 through the separator outlet of the separator 5, thus realizing oil circulation. The oil circulation loop is sequentially equipped with the oil tank 7, high-pressure pump 8, oil quantity regulating valve 9, nozzle 3, mixer 2, compressor 1, and separator 5. Through the circulation of liquid oil, resource conservation can be achieved.

[0040] In some embodiments of the present invention, the supercritical carbon dioxide isothermal compression system further includes a turbine 12, which is located between the separator 5 and the oil tank 7 in the oil circulation loop. Specifically, the oil circulation loop sequentially includes the oil tank 7, high-pressure pump 8, oil quantity regulating valve 9, nozzle 3, mixer 2, compressor 1, separator 5, and turbine 12. The turbine 12 has a turbine inlet and a turbine outlet. The turbine outlet is connected to the turbine inlet, and the turbine outlet is connected to the oil tank inlet. The separator 5 transports the separated liquid oil through the turbine outlet to the turbine inlet. After the liquid oil performs work and releases pressure in the turbine 12, it is discharged from the turbine outlet and enters the oil tank 7 through the oil tank inlet.

[0041] In some embodiments of the present invention, the main shaft 11 of the turbine 12 is coaxially connected to the main shaft of the compressor 1. Specifically, the main shaft 11 of the turbine 12 and the main shaft of the compressor 1 can be directly connected by a coupling, and the axial direction of the main shaft 11 of the turbine 12 and the main shaft of the compressor 1 coincides, so as to transfer the mechanical energy of the turbine 12 to the compressor 1 and realize the efficient utilization of energy.

[0042] In some embodiments of the present invention, the supercritical carbon dioxide isothermal compression system further includes a cooler 6, which is located between the turbine 12 and the oil tank 7 in the oil circulation loop. Specifically, the oil circulation loop sequentially includes the oil tank 7, high-pressure pump 8, oil quantity regulating valve 9, nozzle 3, mixer 2, compressor 1, separator 5, turbine 12, and cooler 6. The cooler 6 has a cooling inlet and a cooling outlet. The cooling inlet is connected to the turbine outlet, and the cooling outlet is connected to the oil tank inlet. Specifically, the liquid oil is heated by work done in the turbine 12. The heated liquid oil is discharged from the turbine outlet and enters the cooling inlet of the cooler 6. The heated liquid oil is cooled in the cooler 6 and discharged from the cooler 6 through the cooling outlet. Finally, it enters the oil tank 7 through the oil tank inlet, thus achieving oil circulation.

[0043] In some embodiments of the present invention, a liquid level regulating valve 10 is provided on the connecting pipeline 13 between the separator 5 and the turbine 12. The oil level in the separator 5 can be adjusted by the liquid level regulating valve to avoid the oil level in the separator 5 being too high and to prevent the oil volume in the separator 5 from being too large and affecting the separation of the gas-liquid mixture of gaseous carbon dioxide and oil.

[0044] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A supercritical carbon dioxide isothermal compression system, characterized in that, The supercritical carbon dioxide isothermal compression system includes: The compressor has a compression inlet and a compression outlet; A mixer connected to the compressor and in communication with the compression inlet, the mixer being used to mix carbon dioxide and oil; A separator, connected to the compression outlet, is used to separate a mixture of carbon dioxide and oil; The mixer has a mixing air inlet and a mixing liquid inlet. The mixing air inlet is used to introduce carbon dioxide, and the mixing liquid inlet is equipped with a nozzle. The nozzle is used to introduce oil and atomize the oil into droplets, so that the droplets and gaseous carbon dioxide are mixed in the mixer to form a uniform gas-liquid mixture. The gas-liquid mixture is compressed in the compressor, and the liquid oil absorbs the heat of compression generated by the compression of gaseous carbon dioxide to achieve isothermal compression. The supercritical carbon dioxide isothermal compression system also includes: The oil tank has an oil tank outlet that is connected to the nozzle. The oil tank is used to supply oil to the nozzle. The separator has a separation outlet. The oil tank has an oil tank inlet that is connected to the separation outlet. A turbine, the turbine having a turbine inlet and a turbine outlet, the separation outlet being connected to the turbine inlet, and the turbine outlet being connected to the oil tank inlet; A cooler having a cooling inlet and a cooling outlet, the cooling inlet being connected to the turbine outlet and the cooling outlet being connected to the oil tank inlet.

2. The supercritical carbon dioxide isothermal compression system according to claim 1, characterized in that, The oil tank and the nozzle are connected by a connecting pipe, and a high-pressure pump is installed on the connecting pipe.

3. The supercritical carbon dioxide isothermal compression system according to claim 2, characterized in that, An oil volume regulating valve is provided on the connecting pipeline, and the oil volume regulating valve is located between the high-pressure pump and the nozzle.

4. The supercritical carbon dioxide isothermal compression system according to claim 1, characterized in that, The turbine's main shaft is coaxially connected to the compressor's main shaft.

5. The supercritical carbon dioxide isothermal compression system according to claim 1, characterized in that, The supercritical carbon dioxide isothermal compression system also includes: A pressure stabilizing tank is connected to the mixing inlet of the mixer, and the pressure stabilizing tank is used to provide the mixer with pressure-stabilized carbon dioxide.

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