Isothermal compression expansion system

Abstract

The present application relates to the technical field of compression, in particular to an isothermal compression expansion system, the isothermal compression expansion system comprises at least two stages of compression expansion units and interstage coolers, two ends of the interstage cooler are connected with adjacent two stages of compression expansion units respectively, the compression expansion unit comprises a piston assembly, a transmission assembly and a cooling assembly, the piston assembly comprises a cylinder, a piston and a piston rod, the piston is arranged in the cylinder, the piston is connected with the piston rod, one end of the piston rod extends out of the cylinder, the piston rod can move along the height direction of the cylinder to compress or expand the gas, two ends of the transmission assembly are connected with the piston rod and a generator respectively, the cooling assembly comprises a water cooling jacket and a nozzle, the water cooling jacket is sleeved on the cylinder, the nozzle is arranged at one end of the cylinder away from the piston rod, the nozzle is used for spraying atomized water into the cylinder, the nozzle and the water cooling jacket are adapted to be connected with a cooling tower, the present application provides an isothermal compression expansion system, and the isothermal compression efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of compression technology, and more specifically to an isothermal compression-expansion system. Background Technology

[0002] Isothermal compression refers to a compression method in which the gas temperature remains constant during the compression process. The isothermal compression expansion system in related technologies includes multi-stage compression expansion units and multiple interstage coolers. Two adjacent compression expansion units are connected to the two ends of an interstage cooler, but the interstage cooler can only cool the gas after each stage of compression, resulting in a reduction in isothermal compression efficiency. Summary of the Invention

[0003] This invention aims to at least partially address one of the technical problems in related technologies. To this end, embodiments of this invention propose an isothermal compression-expansion system that improves isothermal compression efficiency.

[0004] The isothermal compression-expansion system of this invention includes: at least two stages of compression-expansion units; an interstage cooler, one end of which is connected to one stage of the compression-expansion unit and the other end of which is connected to another stage of the compression-expansion unit, the interstage cooler being used to cool or heat the gas compressed or expanded by the first stage of the compression-expansion unit; wherein, the compression-expansion unit includes: a piston assembly, the piston assembly including a cylinder, a piston, and a piston rod, the piston being disposed in the cylinder, the piston being connected to the piston rod, one end of the piston rod extending out of the cylinder, the piston rod being movable along the height direction of the cylinder to compress or expand the gas; a transmission assembly, one end of which is connected to the piston rod, the other end of which is adapted to be connected to a generator; a cooling assembly, the cooling assembly including a water-cooled jacket and a nozzle, the water-cooled jacket being fitted onto the cylinder, the inner wall surface of the water-cooled jacket contacting the outer wall surface of the cylinder, the nozzle being disposed at the end of the cylinder away from the piston rod, the nozzle being used to spray atomized water into the cylinder, the nozzle and the water-cooled jacket being adapted to be connected to a cooling tower.

[0005] The isothermal compression-expansion system of this invention improves isothermal compression efficiency.

[0006] In some embodiments, the isothermal compression-expansion system further includes at least two first pumps, one end of which is connected to the cooling tower and the other end of which is connected to the nozzle, the first pumps being used to pressurize the water flowing through them.

[0007] In some embodiments, the pressure of the water pressurized by the first pump is greater than the working pressure of the cylinder.

[0008] In some embodiments, the compression expansion unit further includes a separator disposed between the cylinder and the interstage cooler, the separator being used to separate water from the gas.

[0009] In some embodiments, the isothermal compression-expansion system further includes a second pump, one end of which is connected to the cooling tower, and the other end of which is connected to the interstage cooler or the water jacket.

[0010] In some embodiments, the interstage cooler has a first channel and a second channel. The two ends of the first channel are respectively connected to two adjacent compression and expansion units so that gas in the compression and expansion units can be introduced to reduce gas pressure fluctuations between the two adjacent compression and expansion units. One end of the second channel is connected to the second pump, and the other end of the second channel is connected to the cooling tower so that water in the cooling tower can be introduced into the second channel. The gas in the first channel and the water in the second channel can exchange heat.

[0011] In some embodiments, the isothermal compression-expansion system further includes a controller connected to the nozzle to adjust the working state of the nozzle. The compression-expansion unit further includes a first valve and a second valve, which are located at the end of the cylinder away from the piston rod to control the intake and exhaust of the cylinder. The first valve and the second valve are connected to the controller.

[0012] In some embodiments, the number of piston assemblies is set to multiple, and the multiple piston assemblies are divided into two groups. The two groups of piston assemblies are arranged at intervals in the height direction of the cylinder body, and each group of piston assemblies includes multiple piston assemblies arranged at intervals along the length direction of the cylinder body.

[0013] In some embodiments, the transmission assembly includes a crankshaft and a plurality of connecting rods, one end of which is connected to the piston rod and the other end of which is connected to the crankshaft.

[0014] In some embodiments, the crankshaft includes a plurality of cranks, which are spaced apart along the length of the cylinder block, and each crank is connected to the connecting rod at both ends along the height of the cylinder block. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the isothermal compression-expansion system according to an embodiment of the present invention.

[0016] Figure label:

[0017] Compression expansion unit 100, interstage cooler 200, second inlet 210, third outlet 220.

[0018] Cooling tower 300, generator 400, first pump 500

[0019] Second pump 600, first inlet 610, first outlet 620, controller 700.

[0020] Piston assembly 1, cylinder 11, piston 12, piston rod 13.

[0021] Transmission assembly 2, crankshaft 21, crank 211, connecting rod 22,

[0022] Cooling assembly 3, water cooling jacket 31, third inlet 311, fourth outlet 312, nozzle 32.

[0023] Separator 4, first valve 5, second valve 6. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] The isothermal compression-expansion system of this invention includes at least two-stage compression-expansion units 100 and an interstage cooler 200, wherein the compression-expansion unit 100 includes a piston assembly 1, a transmission assembly 2 and a cooling assembly 3.

[0026] One end of the interstage cooler 200 is connected to one of the primary compression and expansion units 100, and the other end of the interstage cooler 200 is connected to another compression and expansion unit 100. The interstage cooler 200 is used to cool or heat the gas compressed or expanded by the primary compression and expansion unit 100. The piston assembly 1 includes a cylinder 11, a piston 12, and a piston rod 13. The piston 12 is disposed inside the cylinder 11 and is connected to the piston rod 13. One end of the piston rod 13 extends out of the cylinder 11, and the piston rod 13 can extend along the height direction of the cylinder 11 (e.g., ...). Figure 1 The movement (shown in the up-down direction) compresses or expands the gas. One end of the transmission assembly 2 is connected to the piston rod 13, and the other end of the transmission assembly 2 is adapted to be connected to the generator 400. The cooling assembly 3 includes a water-cooling jacket 31 and a nozzle 32. The water-cooling jacket 31 is fitted onto the cylinder body 11, and the inner wall surface of the water-cooling jacket 31 is in contact with the outer wall surface of the cylinder body 11. The nozzle 32 is located at the end of the cylinder body 11 away from the piston rod 13. The nozzle 32 is used to spray atomized water into the cylinder body 11. The nozzle 32 and the water-cooling jacket 31 are adapted to be connected to the cooling tower 300.

[0027] Specifically, such as Figure 1As shown, the first-stage compression expansion unit 100 is located on the left side of the interstage cooler 200, and the other-stage compression expansion unit is located on the right side of the interstage cooler 200. When the isothermal compression expansion system is used as a compressor, the gas compressed by the first-stage compression expansion unit 100 is transferred to the interstage cooler for cooling before being transferred to the other-stage compression expansion unit 100. When the isothermal compression expansion system is used as an expander, the gas expanded by the other-stage compression expansion unit 100 is transferred to the interstage cooler for heating before being transferred to the first-stage compression expansion unit 100.

[0028] The cylinder 11 is fixed. When the isothermal expansion system acts as a compressor, the generator 400 drives the transmission assembly 2 to rotate. The rotation of the transmission assembly 2 drives the piston rod 13 to move up and down, and the piston rod 13 drives the piston 12 to move up and down, compressing the gas inside the cylinder 11. When the isothermal compression-expansion system acts as an expander, the expansion of the high-pressure gas inside the cylinder 11 pushes the piston rod 13 towards the transmission assembly 2, causing the transmission assembly 2 to move. The movement of the transmission assembly 2 then drives the generator 400 to move. It can be understood that the generator 400 can function as either an electric motor or a generator.

[0029] The water cooling jacket 31 is connected to the cooling tower 300 to transfer water from the cooling tower 300 to the water cooling jacket 31. The water cooling jacket 31 is fitted onto the cylinder 11 and the inner wall of the water cooling jacket 31 contacts the outer wall of the cylinder 11, so that heat exchange occurs between the water in the water cooling jacket 31 and the cylinder 11, thereby heating or cooling the cylinder 11.

[0030] The nozzle 32 is located at the end of the cylinder 11 away from the piston rod 13. The nozzle 32 is connected to the cooling tower 300 to transfer water in the cooling tower 300 to the nozzle 32. Atomized water is sprayed into the cylinder 11 through the nozzle 32. The atomized water exchanges heat with the gas in the cylinder 11, thereby heating or cooling the gas and achieving isothermal compression.

[0031] For example, nozzle 32 is an electronically controlled nozzle 32, and the number of nozzles 32 can be set to multiple. Multiple nozzles 32 spray atomized water into the cylinder 11, which can improve the cooling or heating efficiency of the gas.

[0032] In this embodiment of the invention, during the operation of the piston 12, the cylinder 11 is cooled and heated by a water-cooling jacket 31, the gas is cooled or heated by atomized water sprayed into the cylinder 11 by a nozzle 32 on the cylinder 11, and the gas after each stage of compression or expansion is cooled or heated by an interstage cooler 200 set between adjacent compression and expansion units 100. By combining the cooling or heating of the gas and piston assembly 1 during each stage of compression with the cooling or heating of the gas after each stage of compression, the temperature rise of the piston assembly 1 and the gas is reduced, and the isothermal compression efficiency is improved.

[0033] In some embodiments, the isothermal compression-expansion system further includes at least two first pumps 500, one end of which is connected to the cooling tower 300 and the other end of which is connected to the nozzle 32. The first pumps 500 are used to pressurize the water flowing through them.

[0034] Optionally, the first pump 500 is a high-pressure water pump. By placing the high-pressure water pump between the nozzle 32 and the cooling tower 300, the water flowing through the first pump 500 is pressurized. The pressurized high-pressure water is then transmitted to the nozzle 32 and sprayed into the cylinder 11 in an atomized manner.

[0035] It is understood that each stage of compression expansion unit 100 includes at least one first pump 500. Since the working pressure of the cylinder 11 of each stage of isothermal compression expansion unit 100 is different, a first pump 500 is provided in each stage of isothermal compression expansion unit 100 to provide high-pressure water to each stage of isothermal compression expansion unit 100 in order to adjust the water pressure transmitted to the nozzle 32.

[0036] For example, the first pump 500 is a positive displacement pump or a plunger pump.

[0037] In some embodiments, the pressure of the water pressurized by the first pump 500 is greater than the working pressure of the cylinder 11.

[0038] Optionally, the working pressure of the cylinder 11 refers to the maximum working pressure of the cylinder 11. Only when the pressure of the water pressurized by the first pump 500 is greater than the working pressure of the cylinder 11 can the nozzle 32 spray atomized water into the cylinder 11. If the pressure of the water pressurized by the first pump 500 is less than the working pressure of the cylinder 11, the nozzle 32 cannot spray atomized water into the cylinder 11, and thus the cooling or heating effect cannot be achieved.

[0039] In some embodiments, the compression expansion unit 100 further includes a separator 4 disposed between the cylinder 11 and the interstage cooler 200, the separator 4 being used to separate water from the gas.

[0040] In this embodiment of the invention, a separator 4 is provided to separate excess liquid water in the gas after it has been compressed or expanded by the current compression and expansion unit 100, and the separated gas is then transmitted to the next stage compression and expansion unit 100.

[0041] For example, separator 4 is a gas-water separator 4.

[0042] In some embodiments, the isothermal compression-expansion system further includes a second pump 600, one end of which is connected to the cooling tower 300, and the other end of which is connected to the interstage cooler 200 or the water jacket 31.

[0043] Optionally, the second pump 600 has a first inlet 610, a first outlet 620, and a second outlet (not shown in the figure), and the interstage cooler 200 has a second inlet 210 and a third outlet 220. The first inlet 610 is connected to the cooling tower 300 to transfer water in the cooling tower 300 to the second pump 600. The first outlet 620 is connected to the second inlet 210 to transfer water in the cooling tower 300 to the interstage cooler 200 via the second pump 600. The water circulated in the interstage cooler 200 flows through the third outlet 220 back to the cooling tower 300.

[0044] The water-cooled jacket 31 has a third inlet 311 and a fourth outlet 312. The third inlet 311 is connected to the second outlet to transfer water in the cooling tower 300 to the water-cooled jacket 31. After circulating through the water-cooled jacket 31, the water flows through the second outlet back to the cooling tower 300.

[0045] For example, the second pump 600 is a circulating water pump.

[0046] Understandably, the cooling tower 300 provides sufficient heat exchange capacity to keep the cooling water at approximately the same temperature as the ambient temperature, and provides sufficient water for the first pump 500 and the second pump 600 to exchange heat with the cylinder 11 and the gas inside the cylinder 11, thereby improving the isothermal compression efficiency.

[0047] In some embodiments, the interstage cooler 200 has a first channel (not shown) and a second channel (not shown). The two ends of the first channel are respectively connected to two adjacent compression expansion units 100 so that gas in the compression expansion units 100 can be introduced to reduce the gas pressure fluctuation between the two adjacent compression expansion units 100. One end of the second channel is connected to a second pump 600, and the other end of the second channel is connected to a cooling tower 300 so that water in the cooling tower 300 can be introduced into the second channel. The gas in the first channel and the water in the second channel can exchange heat.

[0048] Specifically, one end of the second channel is the second inlet 210, and the other end of the second channel is the third outlet 220. In this embodiment of the invention, the first and second channels of the stage cooler are set to cool or heat the gas after it has been compressed or expanded by the compression and expansion unit 100 to the ambient temperature, and provide a certain volume to reduce the pressure fluctuation of the exhaust and intake of the adjacent compression and expansion unit 100.

[0049] For example, interstage cooler 200 is a gas-water heat exchanger.

[0050] In some embodiments, the isothermal compression expansion system further includes a controller 700, which is connected to the nozzle 32 to adjust the working state of the nozzle 32. The compression expansion unit 100 also includes a first valve 5 and a second valve 6, which are located at the end of the cylinder 11 away from the piston rod 13 to control the intake and exhaust of the cylinder 11. The first valve 5 and the second valve 6 are connected to the controller 700.

[0051] Specifically, the first valve 5 and the second valve 6 are located on the cylinder body 11, and are positioned on opposite sides of the end of the cylinder body 11 furthest from the piston rod 13. When the isothermal compression-expansion system functions as a compressor, the first valve 5 and the second valve 6 can be one-way valves, automatically opening and closing based on pressure difference. The first valve 5 is connected to the intake pipe of the compression-expansion unit 100, and the second valve 6 is connected to the exhaust pipe of the compression-expansion unit 100. When the isothermal compression-expansion system functions as an expander, the first valve 5 and the second valve 6 are solenoid valves. The first valve 5 is connected to the exhaust pipe of the compression-expansion unit 100, and the second valve 6 is connected to the intake pipe of the compression-expansion unit 100. The second valve 6 introduces high-pressure gas from the high-pressure stage cylinder body 11.

[0052] The controller 700 is connected to the nozzle 32 so that the controller 700 can determine the state of the nozzle 32 according to the movement state of the transmission component 2. When the first valve 5 and the second valve 6 are solenoid valves, the controller 700 is connected to the first valve 5 and the second valve 6 respectively to control the opening and closing of the first valve 5 and the second valve 6, thereby controlling the intake and exhaust of the cylinder 11.

[0053] For example, the controller 700 is a microcontroller or a PLC.

[0054] In some embodiments, the number of piston assemblies 1 is set to multiple, and the multiple piston assemblies 1 are divided into two groups. The two groups of piston assemblies 1 are arranged at intervals in the height direction of the cylinder body 11, and each group of piston assemblies 1 includes multiple piston assemblies 1 arranged at intervals along the length direction of the cylinder body 11.

[0055] Specifically, multiple piston assemblies 1 are divided into two groups, and the two groups of piston assemblies 1 are arranged symmetrically along the transmission assembly 2. That is, the two groups of piston assemblies 1 are arranged symmetrically in the vertical direction, and each group of piston assemblies 1 is arranged at intervals in the horizontal direction. Each piston assembly 1 is connected to the transmission assembly 2.

[0056] It is understood that each stage of compression and expansion unit 100 includes a piston assembly 1, a transmission assembly 2, and a cooling assembly 3. The number of piston assemblies 1, the cylinder diameter of the cylinder 11, and the stroke of the piston 12 in each stage of compression and expansion unit 100 can be the same or different. For example, the number of piston assemblies 1 in the first stage of compression and expansion unit 100 is four, and the number of piston assemblies 1 in the other stage of compression and expansion unit 100 is six. By setting multiple piston assemblies 1, the axial torque distribution can be more balanced, the power of the isothermal compression and expansion system can be improved, and the isothermal compression efficiency can be improved.

[0057] In some embodiments, the transmission assembly 2 includes a crankshaft 21 and a plurality of connecting rods 22, one end of the connecting rod 22 being connected to the piston rod 13 and the other end of the connecting rod 22 being connected to the crankshaft 21.

[0058] Optionally, the transmission assembly 2 also includes a connecting rod 22 piston rod 13 bearing, a crankshaft 21 connecting rod 22 bearing, and a crankshaft 21 support bearing. One end of the connecting rod 22 is hinged to the piston rod 13 via the connecting rod 22 piston rod 13 bearing, and the other end of the connecting rod 22 is hinged to the crankshaft 21 via the crankshaft 21 connecting rod 22 bearing. The crankshaft 21 support bearing is used to support the crankshaft 21 so that the crankshaft 21 can rotate freely. The side of the crankshaft 21 closest to the generator 400 is connected to the generator 400. The rotation of the generator 400 can drive the crankshaft 21 to rotate, and the up-and-down movement of the piston assembly 1 can also drive the crankshaft 21 to rotate.

[0059] For example, piston assembly 1 can also be arranged in a star shape or in a layered arrangement of piston assemblies 1 of different compression stages, which can improve the compactness of the isothermal compression-expansion system. This embodiment of the invention does not specifically limit the arrangement of piston assembly 1 and transmission assembly 2. For instance, a double-acting piston assembly 1 can be used, meaning that the piston 12 can compress and expand the gas in both directions of movement within the cylinder 11, thereby doubling the system capacity of the compression-expansion system and improving the isothermal compression efficiency.

[0060] The transmission component 2 can also be configured as a linearly moving component, such as a screw type or a ball screw type. This invention does not limit the specific structure of the transmission component 2. As long as it can realize the rotational motion of the crankshaft 21 to drive the reciprocating motion of the piston 12, it falls within the protection scope of this invention.

[0061] In some embodiments, the crankshaft 21 includes a plurality of cranks 211, which are spaced apart along the length of the cylinder block 11, and each crank 211 is connected to a connecting rod 22 at both ends along the height of the cylinder block 11.

[0062] Specifically, the other end of the connecting rod 22 is hinged to the crank 211 of the crankshaft 21 through the crankshaft 21 connecting rod 22 bearing. The upper end of the crank 211 is connected to the upper connecting rod 22, and the lower end of the crank 211 is connected to the lower connecting rod 22. The upper piston assembly 1 and the lower piston assembly 1 are arranged symmetrically.

[0063] When the isothermal compression-expansion system is used as a compressor, the cooling tower 300 and the second pump 600 are started, creating a cooling water circulation between the water-cooled jacket 31, the interstage cooler 200, and the cooling tower 300. Then, the first pump 500 and the generator 400 are started. The generator 400 drives the crankshaft 21 to rotate, which in turn drives the connecting rod 22 to move up and down. The connecting rod 22, through the piston rod 13, drives the piston 12 to reciprocate. The water circulating in the water-cooled jacket 31 cools the piston assembly 1. The nozzle 32 sprays high-pressure atomized water into the cylinder 11 to cool the gas inside. The first valve 5 and the second valve 6 on the cylinder 11 open and close sequentially as the piston 12 moves, completing the intake, compression, and exhaust of the piston assembly 1. The gas compressed by the left compression-expansion unit 100 is transferred to the interstage cooler 200, where the gas is further cooled to ambient temperature by the heat exchange of the cooling water. Then, the gas is transferred to the right compression-expansion unit 100 for high-pressure stage compression.

[0064] For example, when the isothermal compression-expansion system is used as a compressor, the opening and closing sequence of the first valve 5 and the second valve 6 can be as follows: when the piston 12 is at the top of the cylinder 11, the first valve 5 is opened to allow air to enter the cylinder 11, and the second valve 6 is closed at this time. When the piston 12 reaches the bottom of the cylinder 11, the first valve 5 is closed to complete the air intake. During the process of the piston 12 moving from the bottom to the top of the cylinder 11, the gas is compressed. When the gas pressure in the cylinder 11 is greater than the pressure in the exhaust pipe on the side of the second valve 6, the second valve 6 is opened to exhaust the gas. When the piston 12 moves to the top of the cylinder 11, the second valve 6 is closed to complete the exhaust.

[0065] When the compressor has finished intake and the second valve 6 is closed, the piston 12 begins to move upward, and the controller 700 controls the nozzle 32 to spray high-pressure atomized water into the cylinder 11.

[0066] When the isothermal compression-expansion system is used as an expander, the cooling tower 300 and the second pump 600 are started to form a cooling water circulation between the water-cooled jacket 31, the interstage cooler 200, and the cooling tower 300. Then the first pump 500 is started to introduce high-pressure gas from the compression-expansion unit 100 of the right high-pressure stage. After being heated to the ambient temperature by the interstage cooler 200, the gas is transferred to the left compression-expansion unit 100 for expansion. The high-pressure gas enters the cylinder 11 through the second valve 6. Under the action of the high-pressure gas, the piston 12 drives the connecting rod 22 to reciprocate. The connecting rod 22 drives the crankshaft 21 to rotate, which in turn drives the generator 400 to move. The water circulation in the water-cooled jacket 31 heats the piston assembly 1. The nozzle 32 sprays high-pressure atomized water into the cylinder 11 to heat the gas in the cylinder 11. The first valve 5 and the second valve 6 on the cylinder 11 are opened and closed in sequence under the control of the controller 700 to complete the intake, expansion, and exhaust of the piston assembly 1.

[0067] For example, when the isothermal compression-expansion system is used as an expander, the opening and closing sequence of the first valve 5 and the second valve 6 can be as follows: when the piston 12 is at the top of the cylinder 11, the second valve 6 is opened to allow air in, and the first valve 5 is closed. When the high-pressure gas content in the cylinder 11 reaches the set requirement, the second valve 6 is closed to complete the air intake. After the piston 12 moves to the bottom of the cylinder 11 under the action of gas expansion to complete the gas expansion, that is, when the piston 12 moves to the bottom of the cylinder 11, the first valve 5 is opened to allow exhaust, until the cylinder 11 moves to the top of the cylinder 11, and then the first valve 5 is closed.

[0068] When the expander completes the intake and the gas enters the expansion process, the controller 700 controls the nozzle 32 to open and spray high-pressure atomized water until the expansion process is completed.

[0069] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0070] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0071] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0072] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above" or "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below" or "below" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0073] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] It is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An isothermal compression-expansion system, characterized in that, include: At least two stages of compression and expansion units; An interstage cooler, one end of which is connected to one of the primary compression and expansion units, and the other end of which is connected to another compression and expansion unit, is used to cool or heat the gas compressed or expanded by the primary compression and expansion unit. The compression and expansion unit includes: A piston assembly, comprising a cylinder, a piston, and a piston rod, wherein the piston is disposed within the cylinder and connected to the piston rod, one end of the piston rod extending out of the cylinder, and the piston rod is movable along the height direction of the cylinder to compress or expand gas; A transmission assembly, one end of which is connected to the piston rod, and the other end of which is adapted to be connected to a generator; A cooling assembly, comprising a water-cooled jacket and a nozzle, wherein the water-cooled jacket is fitted onto the cylinder body and the inner wall surface of the water-cooled jacket contacts the outer wall surface of the cylinder body, the nozzle is located at the end of the cylinder body away from the piston rod, the nozzle is used to spray atomized water into the cylinder body, the nozzle and the water-cooled jacket are adapted to be connected to a cooling tower, the nozzle is an electrically controlled nozzle, and the number of nozzles is set to multiple; It also includes at least two first pumps, one end of which is connected to the cooling tower and the other end of which is connected to the nozzle. The first pump is used to pressurize the water flowing through it. It also includes a controller connected to the nozzle to adjust the operating state of the nozzle; When the isothermal compression-expansion system is used as a compressor, the cooling tower and the second pump are started to create a cooling water circulation between the water-cooled jacket, the interstage cooler, and the cooling tower. Then, the first pump and the generator are started. The generator drives the crankshaft to rotate, and the crankshaft drives the connecting rod to move up and down. The connecting rod drives the piston to reciprocate through the piston rod. The water in the water-cooled jacket circulates to cool the piston assembly. The nozzle sprays high-pressure atomized water into the cylinder to cool the gas inside the cylinder. The first valve and the second valve on the cylinder open and close sequentially as the piston moves, completing the intake, compression, and exhaust of the piston assembly. The gas compressed by the left compression-expansion unit is transferred to the interstage cooler. The interstage cooler further cools the gas to ambient temperature under the heat exchange of the cooling water, and then transfers it to the right compression-expansion unit for high-pressure stage compression. When the isothermal compression-expansion system is used as an expander, the cooling tower and the second pump are started to create a cooling water circulation between the water-cooled jacket, the interstage cooler, and the cooling tower. Then, the first pump is started to introduce high-pressure gas from the compression-expansion unit of the right high-pressure stage. After being heated to ambient temperature by the interstage cooler, the gas is transferred to the left compression-expansion unit for expansion. The high-pressure gas enters the cylinder through the second valve. Under the action of the high-pressure gas, the piston drives the connecting rod to reciprocate. The connecting rod drives the crankshaft to rotate, which in turn drives the generator. The water circulation in the water-cooled jacket heats the piston assembly. The nozzle sprays high-pressure atomized water into the cylinder to heat the gas inside the cylinder. The first and second valves on the cylinder are opened and closed sequentially under the control of the controller to complete the intake, expansion, and exhaust of the piston assembly.

2. The isothermal compression-expansion system according to claim 1, characterized in that, The pressure of the water pressurized by the first pump is greater than the working pressure of the cylinder.

3. The isothermal compression-expansion system according to claim 2, characterized in that, The compression and expansion unit also includes a separator disposed between the cylinder and the interstage cooler, the separator being used to separate water from the gas.

4. The isothermal compression-expansion system according to claim 1, characterized in that, It also includes a second pump, one end of which is connected to the cooling tower, and the other end of which is connected to the interstage cooler or the water jacket.

5. The isothermal compression-expansion system according to claim 4, characterized in that, The interstage cooler has a first channel and a second channel. The two ends of the first channel are respectively connected to two adjacent compression and expansion units so that gas in the compression and expansion units can be introduced to reduce the gas pressure fluctuation between the two adjacent compression and expansion units. One end of the second channel is connected to the second pump, and the other end of the second channel is connected to the cooling tower so that water in the cooling tower can be introduced into the second channel. The gas in the first channel and the water in the second channel can exchange heat.

6. The isothermal compression-expansion system according to claim 1, characterized in that, The compression and expansion unit further includes a first valve and a second valve, which are located at the end of the cylinder away from the piston rod to control the intake and exhaust of the cylinder, and the first valve and the second valve are connected to the controller.

7. The isothermal compression-expansion system according to claim 1, characterized in that, The number of piston assemblies is set to multiple, and the multiple piston assemblies are divided into two groups. The two groups of piston assemblies are arranged at intervals in the height direction of the cylinder body, and each group of piston assemblies includes multiple piston assemblies arranged at intervals along the length direction of the cylinder body.

8. The isothermal compression-expansion system according to claim 7, characterized in that, The transmission assembly includes a crankshaft and multiple connecting rods, one end of which is connected to the piston rod, and the other end of which is connected to the crankshaft.

9. The isothermal compression-expansion system according to claim 8, characterized in that, The crankshaft includes multiple cranks, which are spaced apart along the length of the cylinder block. Each crank is connected to the connecting rod at both ends along the height of the cylinder block.

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