A pressure-variable expander, a compressed air energy storage expansion system and a control method

Abstract

The present application discloses a variable pressure expander, a compressed air energy storage expansion system and a control method, wherein the variable pressure expander comprises: an inner casing, which comprises an inlet and an outlet, and the inner wall of the inner casing is provided with a plurality of stationary blades evenly distributed along its axial direction; a rotating shaft, which is rotatably arranged on the inner axis of the inner casing, and the outer wall of the rotating shaft is provided with a plurality of moving blades evenly distributed along its axial direction, and the plurality of stationary blades and the plurality of moving blades are staggered, and the adjacent stationary blades and the moving blades form a group of blade stages, and the adjacent blade stages are provided with blade stage gaps. The variable pressure expander of the present application is provided with a plurality of bypass pipes to eliminate the adverse effects of changes in volume flow caused by large fluctuations in intake pressure; when the intake pressure drops, the bypass is performed step by step, which not only ensures that the flow of gas between the blades can meet the requirements, but also ensures that the stages not bypassed always run in the high-efficiency zone, thereby improving the efficiency of the whole machine.

Description

Technical Field

[0001] The present application relates to the technical field of compressed air energy storage, and in particular to a variable pressure expander, a compressed air energy storage expander system and a control method. Background Art

[0002] Compressed air energy storage is a large-scale energy storage technology that converts electrical energy into air pressure potential energy and thermal energy of heat storage medium for storage, and converts it back into electrical energy during peak electricity consumption. It uses excess power from the power grid to store electrical energy through compressed air through a compressor, and transports the compressed air to rock caves, abandoned salt caves, abandoned mines or other pressure vessels; during periods of high load on the power grid, the high-pressure gas in the gas storage is released, heated by a combustion chamber or heat exchanger, raised to a certain temperature and sent to the expander, converting the pressure potential energy and thermal potential energy of the compressed air into mechanical work output of the expander, driving the generator to generate electricity.

[0003] At present, compressed air energy storage is still mainly in the stage of theoretical research and engineering demonstration. Its expander system has the following problems in practical application:

[0004] 1. During the energy release process of the traditional expander, the range of the expander inlet pressure change is relatively narrow, and at the end of the energy release, there is a lot of residual compressed air in the high-pressure gas storage, which increases the space demand and investment cost of the high-pressure gas storage; 2. During the energy release process of the traditional expander, the pressure of the high-pressure gas storage gradually decreases, and it is not easy for the expander system to achieve stable load operation. In most existing compressed air energy storage systems, a throttle valve is used to reduce the pressure of the stored gas to a specific value before entering the expander to do work, which causes energy loss and reduced system efficiency. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a variable pressure expander, a compressed air energy storage expansion system and a control method, and the specific scheme is as follows:

[0006] A variable pressure expander, comprising:

[0007] An inner casing, comprising an inlet and an outlet, wherein the inner wall of the inner casing is provided with a plurality of stationary blades evenly distributed along the axial direction thereof;

[0008] A rotating shaft, which is rotatably arranged on the inner axis of the inner shell, a plurality of moving blades evenly distributed along the axis direction thereof are arranged on the outer wall of the rotating shaft, a plurality of the stationary blades and a plurality of the moving blades are staggered, adjacent stationary blades and moving blades form a group of blade stages, and a blade stage gap is formed between adjacent blade stages;

[0009] The outer shell is arranged outside the inner shell, and a plurality of bypass pipes are arranged on the outer shell, and the plurality of bypass pipes penetrate the outer shell and are respectively connected with the corresponding blade stage gaps, and the bypass pipes are respectively provided with regulating valves. The variable pressure expander eliminates the adverse effects of volume flow changes caused by large intake pressure fluctuations by arranging a plurality of bypass pipes.

[0010] As an optional embodiment, a cavity is formed between the inner wall of the outer shell and the outer wall of the inner shell, and a plurality of first partitions are provided in the cavity to divide the cavity into a plurality of connecting cavities corresponding to the blade-level gaps, respectively. The gas outlet end of the bypass duct is connected to the inlet of the corresponding connecting cavity, and the outlet of the connecting cavity is connected to the corresponding blade-level gap, so that the bypass duct is connected to the corresponding blade-level gap through the corresponding connecting cavity. The gas enters different connecting cavities from the bypass duct, and then enters the blade-level gap through the outlet of the connecting cavity, so that the air intake is more uniform and has less influence on the flow of gas between the blades.

[0011] As an optional embodiment, the inlet of the inner shell is arranged on its outer peripheral wall, and the variable pressure expander further comprises: a bypass chamber, which is arranged on the outer side of the outer shell, the bypass chamber comprises an inlet and a plurality of outlets, the outlets of the bypass chamber are respectively connected to the bypass pipeline and the main gas pipeline, the main gas pipeline is connected to the inlet of the inner shell, and a regulating valve for opening and closing the bypass pipeline is arranged in the bypass chamber. The bypass chamber can serve as a buffer zone for gas pressure, which helps to stabilize the pressure inside the expander and prevent pressure fluctuations from damaging the equipment.

[0012] As an optional embodiment, a cavity is formed between the inner wall of the outer shell and the outer wall of the inner shell, the bypass pipe is embedded in the inner wall of the inner shell, and the inlet of the cavity is connected to the inlet of the inner shell. The present application combines the bypass pipe with the inner shell to reduce the occupied space without affecting the use, and the structure is more compact.

[0013] As an optional embodiment, a second partition is provided in the cavity to divide the cavity into a first inner cavity and a second inner cavity, a plurality of evenly distributed first partitions are provided in the second inner cavity to divide the second inner cavity into a plurality of connecting cavities corresponding to the blade-level gaps, the bypass pipe is embedded in the second partition, and the inlet of the inner shell is connected to the inlet of the cavity. Through the reasonable layout of the cavity, the gas can flow in smoothly, and the blade-level gaps are effectively replenished.

[0014] As an optional embodiment, the inlet of the inner shell is arranged on its outer peripheral wall, and the outer shell is provided with a main gas pipeline, which is communicated with the inlet of the inner shell through the first inner cavity. Gas is delivered to the inside of the expander through the main gas pipeline, and the gas is diverted to the connecting cavity at the same time, so as to buffer the pressure of the delivered gas and reduce the pressure shock when the gas enters the expander, thereby protecting the components inside the expander.

[0015] As an optional embodiment, the bypass pipe is arranged on the outer peripheral wall of the outer shell or on the end surface of the outer shell. The present application can flexibly set the position of the bypass pipe according to the use environment of the equipment to meet different installation requirements.

[0016] A compressed air energy storage expansion system comprises the aforementioned variable pressure expander, and further comprises:

[0017] A high-pressure gas storage reservoir, the gas outlet of which is connected to the gas inlet of the quick-closing valve;

[0018] A heat exchanger, wherein the cold side inlet is connected to the gas outlet of the quick-closing valve, and the cold side outlet is respectively connected to the gas supply valve, the regulating valve and the inlet of the variable pressure expander;

[0019] a generator connected to the output shaft of the variable pressure expander to generate electricity at the output of the variable pressure expander;

[0020] The inlet of the constant pressure expander is connected to the outlet of the variable pressure expander and the air supply valve respectively. The expansion system is flexible to adjust, which can ensure stable load output and improve the cycle efficiency and energy storage density of the system.

[0021] A control method, comprising:

[0022] In response to the acquired operation instruction, controlling the compressed air in the high-pressure gas storage to expand and perform work;

[0023] Acquire a first parameter, wherein the first parameter is used to characterize an intake pressure of the pressure variable expander;

[0024] Acquire a second parameter, wherein the second parameter is used to characterize the pressure at the air outlet position of each stage of blades;

[0025] determining a target blade level based on the first parameter and the second parameter;

[0026] Based on the target blade level, the opening of the valve assembly is changed, wherein the position of the valve assembly corresponds to the position of the target blade level. The compressed air energy storage expansion system is used by the control method to adapt to the large pressure fluctuations of the gas storage reservoir, and the expander power output is constant and efficient, which greatly improves the cycle efficiency and energy storage density of the system.

[0027] As an optional embodiment, determining the target blade level based on the first parameter and the second parameter includes:

[0028] determining a reference parameter based on the second parameter and the target expansion ratio;

[0029] comparing the reference parameter and the first parameter;

[0030] Based on the comparison result, the target blade level is determined.

[0031] The beneficial effects of the embodiments of the present application are:

[0032] The variable pressure expander of the present application is provided with a plurality of bypass pipes to eliminate the adverse effects of volume flow changes caused by large fluctuations in intake pressure; when the inlet pressure drops, the step-by-step bypass method is used to not only ensure that the flow of gas between the blades can meet the requirements, but also ensure that the non-bypassed stages always operate in the high-efficiency zone, thereby improving the efficiency of the entire machine.

[0033] The expansion system of the present invention has simple equipment, compact structure and low investment cost; the expansion system is flexible to adjust, which can ensure stable load output and improve the circulation efficiency and energy storage density of the system; the expansion ratio of the expansion system has a wide range of variation, which can make full use of the compressed air of the high-pressure gas storage reservoir, and can greatly reduce the space requirement and investment cost of the high-pressure gas storage reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic structural diagram of the pressure variable expander of Example 1 of the present application;

[0035] Figure 2 This is a schematic structural diagram of a pressure variable expander according to Example 2 of the present application;

[0036] Figure 3 This is a schematic structural diagram of a pressure variable expander according to Example 3 of the present application;

[0037] Figure 4 This is a schematic structural diagram of a pressure variable expander according to Example 4 of the present application;

[0038] Figure 5 This is a schematic structural diagram of a pressure variable expander according to Example 5 of the present application;

[0039] Figure 6 This is a schematic structural diagram of a pressure variable expander according to Example 6 of the present application;

[0040] Figure 7 This is a schematic structural diagram of a pressure variable expander according to Example 7 of the present application;

[0041] Figure 8 This is a schematic structural diagram of a pressure variable expander according to Example 8 of the present application;

[0042] Fig. 9 This is a schematic structural diagram of a pressure variable expander according to Example 9 of the present application;

[0043] Fig.10 This is a schematic structural diagram of a pressure variable expander according to Example 10 of the present application;

[0044] Fig.11 This is a schematic structural diagram of a compressed air energy storage expansion system according to Example 11 of the present application;

[0045] Fig.12 for Fig. 9 A-direction view group.

[0046] Reference numerals:

[0047] A. High-pressure gas storage; B. Heat exchanger; C. Variable pressure expander; D. Generator; E. Constant pressure expander; 1. Quick-closing valve; 2. Inlet of cold side of heat exchanger; 3. Outlet of cold side of heat exchanger; 4. Air supply valve; 5. Regulating valve; 6. Bypass pipe; 7. Bypass chamber; 8. First partition; 9. Blade stage clearance; 10. Main gas pipeline; 11. Inner casing; 12. Stationary blades; 13. Rotating shaft; 14. Moving blades; 15. Outer casing; 16. Cavity; 17. Second partition; 18. First inner cavity; 19. Connecting cavity. DETAILED DESCRIPTION

[0048] Various aspects and features of the present application are described herein with reference to the accompanying drawings.

[0049] It should be understood that various modifications may be made to the embodiments of the present application. Therefore, the above description should not be considered as limiting, but only as an example of an embodiment. Other modifications within the scope and spirit of the present application will occur to those skilled in the art.

[0050] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present application and, together with the general description of the present application given above and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0051] These and other characteristics of the present application will become apparent from the following description of a preferred form of embodiment given as a non-limiting example with reference to the accompanying drawings.

[0052] It should also be understood that although the present application has been described with reference to some specific examples, those skilled in the art will be able to readily implement many other equivalent forms of the present application.

[0053] The above and other aspects, features and advantages of the present application will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings.

[0054] Specific embodiments of the present application are described hereinafter with reference to the accompanying drawings; however, it should be understood that the embodiments applied for are merely examples of the present application, which may be implemented in a variety of ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that obscure the present application. Therefore, the specific structural and functional details applied for herein are not intended to be limiting, but merely serve as a basis and representative basis for the claims to teach those skilled in the art to use the present application in a variety of ways with substantially any suitable detailed structure.

[0055] This specification may use the phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," all of which may refer to one or more of the same or different embodiments according to the present application.

[0056] Example 1

[0057] The present application embodiment provides a variable pressure expander, such as Figure 1 As shown, it comprises an inner casing 11, a rotating shaft 13 and an outer casing 15. The inner casing 11 comprises an inlet and an outlet, and a plurality of stationary blades 12 are evenly distributed along the axial direction thereof on the inner wall of the inner casing 11.

[0058] The rotating shaft 13 is rotatably arranged on the internal axis of the inner shell 11, and a plurality of moving blades 14 are evenly distributed along the axial direction thereof on the outer wall of the rotating shaft 13, and a plurality of the stationary blades 12 and a plurality of the moving blades 14 are staggeredly distributed, and adjacent stationary blades 12 and moving blades 14 form a group of blade stages, and a blade stage gap 9 is formed between adjacent blade stages.

[0059] The outer shell 15 is disposed on the outer side of the inner shell 11 . A plurality of bypass pipes 6 are disposed on the outer shell 15 . The bypass pipes 6 are disposed on the outer peripheral wall of the outer shell 15 .

[0060] The plurality of bypass pipes 6 penetrate the outer shell 15 and are respectively connected to the corresponding blade stage gaps 9, and the bypass pipes 6 are respectively provided with regulating valves 5. Among them, at least one bypass pipe 6 is provided at a position corresponding to the blade stage gap 9, and the regulating valve 5 controls the intake flow of the bypass pipe 6.

[0061] Typically, the pressure variation range of the inlet of the inner casing 11 is within the range of 2MPa-15MPa, and the temperature variation range of the inlet is 100°C-300°C. The number of blade stages of the variable pressure expander C is greater than or equal to two stages. In the present application, the multi-stage blade stages are divided into first-stage blades, second-stage blades, ... N-1-stage blades, and N-stage blades.

[0062] Similarly, the multiple blade level gaps 9 in the present application can be divided into a first-level blade level gap, a second-level blade level gap...an N-1th-level blade level gap and an Nth-level blade level gap, and the multiple bypass pipes 6 in the present application can be divided into a first-level bypass pipe, a second-level bypass pipe...an N-1th-level bypass pipe and an Nth-level bypass pipe, the first-level blade level gap corresponds to the first-level bypass pipe, and the other-level blade level gaps correspond to and are connected with the other-level bypass pipes in sequence.

[0063] In this embodiment, the gas enters from the inlet a of the inner casing 11. When the pressure at the outlet position of the first-stage blade is lower than the normal value, the gas is supplemented through the bypass pipe 6, and the gas enters the blade gap 9 between the first-stage blade and the second-stage blade from the bypass pipe 6. The gas entering from the inlet of the inner casing 11 and the gas entering from the bypass pipe 6 have the same source.

[0064] Specifically, when the intake pressure at the inlet a of the inner casing 11 gradually decreases and the intake volume flow rate increases, if the first-stage blades cannot meet the flow of the volume flow rate, the opening of the regulating valve 5 of the first-stage bypass pipe b6 is increased, and air is supplemented at the exhaust position of the first-stage blades (i.e., the first-stage blade stage gap 9) to meet the flow requirement. At the same time, the exhaust pressure of the first-stage blades is maintained constant, and the blades of all subsequent stages still work at the design point, and their flow efficiency is relatively high.

[0065] Similarly, when the pressure at the inlet a of the inner casing 11 continues to drop and the exhaust pressure of the first-stage blades cannot be maintained, the opening of the regulating valve 5 corresponding to the first-stage blades is gradually closed, and the opening of the regulating valve 5 of the second-stage bypass pipe c6 is increased, and air is supplemented at the exhaust position of the second-stage blades (i.e., the second-stage blade level gap) to meet the flow requirements. At the same time, the exhaust pressure of the second-stage blades is maintained constant, and the blades of all subsequent stages still work at the design point, and their flow efficiency is relatively high.

[0066] Example 2

[0067] On the basis of Example 1, Figure 2 As shown, a cavity 16 is formed between the inner wall of the outer shell 15 and the outer wall of the inner shell 11, and a plurality of first partitions 8 are provided in the cavity 16 to divide the cavity 16 into connecting cavities 19 corresponding to the blade stage gaps 9. The connecting cavity 19 can be divided into a first-stage connecting cavity, a second-stage connecting cavity, ..., an N-1-stage connecting cavity, and an N-stage connecting cavity in sequence.

[0068] The air outlet end of the bypass pipe 6 is connected to the inlet of the corresponding connecting cavity 19 , and the outlet of the connecting cavity 19 is connected to the corresponding blade stage gap 9 , so that the bypass pipe 6 is connected to the corresponding blade stage gap 9 through the corresponding connecting cavity 19 .

[0069] The outlet of the connecting cavity 19 is an annular structure and corresponds to the blade stage gap 9. This is to avoid the situation where the gas entering the blade stage gap 9 from the bypass pipe 6 is uneven and causes a large intake loss, which is beneficial to improving the flow efficiency of the blade.

[0070] In this embodiment, the gas first enters different connecting cavities 19 from the bypass pipe 6, then enters the blade stage gap 9 through the outlet of the connecting cavity 19, and merges with the gas entering from the inlet of the inner shell 11, so that the air intake is more uniform and has less impact on the flow of gas between the blades.

[0071] Example 3

[0072] On the basis of Example 1, Figure 3 As shown, the inlet a of the inner shell 11 is arranged on its outer peripheral wall, and the variable pressure expander C also includes a bypass chamber 7, which is arranged on the outer side of the outer shell 15, and the bypass chamber 7 includes an inlet and multiple outlets, and the outlets of the bypass chamber 7 are respectively connected to the bypass pipe 6 and the main gas pipe 10, and the main gas pipe 10 is connected to the inlet a of the inner shell 11, and the bypass chamber 7 is provided with a regulating valve 5 for opening and closing the bypass pipe 6.

[0073] In this embodiment, the gas directly enters the bypass chamber 7 and is then distributed to the main gas duct 10 and each bypass duct 6. The main gas duct 10 is used to allow the gas to directly enter the air intake position of the first-stage blade from the bypass chamber 7, wherein at least one main gas duct 10 is arranged in front of the first-stage blade.

[0074] In this embodiment, the bypass chamber 7 can serve as a buffer zone for gas pressure, which helps stabilize the pressure inside the expander and prevents pressure fluctuations from damaging the equipment. The presence of the bypass chamber 7 makes the maintenance and overhaul of the expander more convenient because the gas flow path can be more easily isolated and inspected.

[0075] In addition, the bypass chamber 7 can be used as a gas temperature adjustment zone to help control the gas temperature to meet the working requirements of the expander. Alternatively, the bypass chamber 7 can also be used as a safety device. When an abnormality occurs inside the expander, the gas can be safely guided out through the bypass chamber 7 to avoid causing greater damage to the equipment.

[0076] Example 4

[0077] On the basis of Example 2, Figure 4As shown, the inlet a of the inner shell 11 is arranged on its outer peripheral wall, and the variable pressure expander C also includes a bypass chamber 7, which is arranged on the outer side of the outer shell 15, and the bypass chamber 7 includes an inlet and multiple outlets, and the outlets of the bypass chamber 7 are respectively connected to the bypass pipe 6 and the main gas pipe 10, and the main gas pipe 10 is connected to the inlet of the inner shell 11. The bypass chamber 7 is provided with a regulating valve 5 for opening and closing the bypass pipe 6.

[0078] In this embodiment, the gas directly enters the bypass chamber 7 and is then distributed to the main gas duct 10 and each bypass duct 6. The main gas duct 10 is used to allow the gas to directly enter the air intake position of the first-stage blade from the bypass chamber 7, wherein at least one main gas duct 10 is arranged in front of the first-stage blade.

[0079] Furthermore, the gas enters the connecting chamber 19 from the bypass pipe 6, and then enters the corresponding blade stage gap 9 from the connecting chamber 19. The bypass chamber 7 can serve as a buffer zone for gas pressure, which helps to stabilize the pressure inside the expander and prevent pressure fluctuations from causing damage to the equipment.

[0080] Example 5

[0081] On the basis of Example 1, Figure 5 As shown, a cavity 16 is formed between the inner wall of the outer shell 15 and the outer wall of the inner shell 11, the bypass pipe 6 is embedded in the inner wall of the inner shell 11, and the inlet of the cavity 16 is connected to the inlet of the inner shell 11. When in use, the gas enters from the inlet a of the inner shell 11 and is diverted into the cavity 16; then, by opening the regulating valve 5, the gas in the cavity 16 is transported to the corresponding blade level gap 9. The present application combines the bypass pipe with the inner shell 11, which reduces the occupied space without affecting the use, and the structure is more compact.

[0082] Example 6

[0083] On the basis of Example 2, Figure 6 As shown, a second partition plate 17 is provided in the cavity 16 to divide the cavity 16 into a first inner cavity 18 and a second inner cavity, and a plurality of evenly distributed first partition plates 8 are provided in the second inner cavity to divide the second inner cavity into a plurality of connecting cavities 19 respectively corresponding to the blade stage gaps 9. The bypass pipe 6 is embedded in the second partition plate 17, and the inlet of the inner shell 11 is communicated with the inlet of the cavity 16.

[0084] When in use, the gas enters from the inlet of the inner shell 11 and is diverted to the first inner cavity 18. As the regulating valve 5 is opened, the gas is diverted to different connecting cavities 19 in turn, and enters the corresponding blade level gap 9 through the connecting cavity 19. Among them, the outlet of the connecting cavity 19 and the inlet of the blade level gap 9 are both annular structures, which is conducive to improving the uniformity of the intake air.

[0085] Example 7

[0086] On the basis of Example 2, Figure 7 As shown, the inlet of the inner shell 11 is arranged on its outer peripheral wall, and the outer shell 15 is provided with a main gas pipeline 10, and the main gas pipeline 10 is connected with the inlet of the inner shell 11 through the first inner cavity 18.

[0087] When in use, the gas enters the first inner cavity 18 through the main gas pipeline 10, and then flows into the air intake position of the first-stage blade. As the regulating valve 5 is opened, the gas in the first inner cavity 18 is then diverted to different connecting cavities 19 in turn, and enters the corresponding blade-level gap 9 through the connecting cavity 19. Among them, the outlet of the connecting cavity 19 and the inlet of the blade-level gap 9 are both annular structures, which can increase the area of ​​air intake and make the air intake more uniform.

[0088] In addition, gas is delivered to the inside of the expander through the main gas pipeline 10, and the gas is diverted to the connecting chamber 19 to buffer the pressure of the delivered gas and reduce the pressure shock when the gas enters the expander, thereby protecting the components inside the expander.

[0089] Example 8

[0090] On the basis of Example 2, Figure 8 As shown, the cavity 16 is divided into a first inner cavity 18 and a plurality of connecting cavities 19 by the first partition plate 8 and the second partition plate 17, and the connecting cavity 19 is connected to the blade stage gap 9. The bypass pipe 6 is embedded in the first partition plate 8 and located on the same center line, and the regulating valve 5 can control the air intake of the connecting cavity 19 respectively.

[0091] When in use, the gas enters from the inlet a of the inner shell 11 and is diverted to the first inner cavity 18. As the regulating valve 5 is opened, the gas in the first inner cavity 18 is diverted to different connecting cavities 19 in turn, and enters the corresponding blade-level gap 9 through the connecting cavity 19. Among them, the outlet of the connecting cavity 19 and the inlet of the blade-level gap 9 are both annular structures. That is, the present application allows the gas to flow in smoothly through the reasonable layout of the cavity 16, and effectively replenishes the blade-level gap 9.

[0092] Example 9

[0093] On the basis of Example 1, Fig. 9As shown, the bypass duct 6 is arranged on the end surface of the outer shell 15. The bypass duct 6 is an inverted L-shaped structure, which includes a horizontal section and a vertical section that are connected to each other, the two ends of the horizontal section are respectively an air inlet end and a connecting end, the two ends of the vertical section are respectively a connecting end and an air outlet end, the connecting end of the horizontal section is connected to the connecting end of the vertical section, and the air outlet end of the vertical section is connected to the inlet of the blade stage gap 9.

[0094] like Fig.12 As shown, at least one bypass duct 6 is provided in each blade stage gap 9, and a plurality of bypass ducts 6 may be circumferentially arranged on the end surface of the outer shell 15 in a circular form, that is, a plurality of bypass ducts 6 are arranged according to the same radius.

[0095] Alternatively, for example, the plurality of bypass pipes 6 are divided into two groups, and the two groups of bypass pipes 6 are circumferentially arranged in the form of concentric circles on the end surface of the outer shell 15. There can be a one-to-one correspondence between the two groups of bypass pipes 6, that is, the two groups of bypass pipes 6 are arranged according to different radii and along the same radial line. In addition, in actual use, the bypass pipes 6 can also be arranged in multiple groups.

[0096] The two groups of bypass pipes 6 may also be in a staggered relationship, that is, the two groups of bypass pipes 6 are arranged according to different radii and along different radial lines. The present application can flexibly set the position of the bypass pipe 6 according to the use environment of the equipment, and meet different installation requirements while saving occupied space.

[0097] Example 10

[0098] 0 Based on Example 2, Fig.10 As shown, the bypass pipe 6 is arranged on the end surface of the outer shell 15. The air inlet end of the bypass pipe 6 is penetrated on the end surface of the outer shell 15, and the air outlet end of the bypass pipe 6 is penetrated on the first partition plate 8 and communicated with the inlet of the corresponding connecting cavity 19, and the outlet of the connecting cavity 19 is communicated with the inlet of the blade stage gap 9.

[0099] like Fig.12 As shown (can also be Fig.10 (view from right to left), at least one bypass duct 6 is provided in each blade stage gap 9, and a plurality of the bypass ducts 6 may be circumferentially arranged in a circular form on the end surface of the outer shell 15, that is, the plurality of the bypass ducts 6 are arranged according to the same radius.

[0100] Alternatively, for example, the plurality of bypass pipes 6 are divided into two groups, and the two groups of bypass pipes 6 are circumferentially arranged in the form of concentric circles on the end surface of the outer shell 15. There can be a one-to-one correspondence between the two groups of bypass pipes 6, that is, the two groups of bypass pipes 6 are arranged according to different radii and along the same radial line. In addition, in actual use, the bypass pipes 6 can also be arranged in multiple groups.

[0101] The two groups of bypass pipes 6 may also be in a staggered relationship, that is, the two groups of bypass pipes 6 are arranged according to different radii and along different radial lines. The present application can flexibly set the position of the bypass pipe 6 according to the use environment of the equipment, and meet different installation requirements while saving occupied space.

[0102] Embodiment 11

[0103] The present application also provides a compressed air energy storage expansion system, such as Fig.11 As shown, it includes the aforementioned variable pressure expander C, and also includes a high-pressure gas storage reservoir A, a heat exchanger B, a generator D and a constant pressure expander E.

[0104] The outlet of the high-pressure gas storage reservoir A is connected to the inlet of the quick-closing valve 1, the cold side inlet of the heat exchanger B is connected to the outlet of the quick-closing valve, and its cold side outlet is respectively connected to the air supply valve 4, the regulating valve 5 and the inlet of the variable pressure expander C, the hot side inlet of the heat exchanger B is connected to the heat storage tank, and its hot side outlet is connected to the cold storage tank. Usually, the air supply valve 4 is a regulating valve 5, which can be operated and maintained at any opening. The air supply valve 4 is hydraulically, pneumatically or electro-hydraulically operated and controlled.

[0105] The generator D is connected to the output shaft of the variable pressure expander C to generate electricity at the output of the variable pressure expander C. The inlet of the constant pressure expander E is connected to the outlet of the variable pressure expander C and the air supply valve 4 respectively.

[0106] The number of blades in the pressure-variable expander C is greater than two. The exhaust pressure of the pressure-variable expander C remains unchanged. The inlet pressure of the pressure-variable expander C varies within the range of 2MPa - 15MPa, and the inlet temperature is within the range of 100-300°C. The total output power of the pressure-variable expander C and the constant pressure expander E is constant.

[0107] In this embodiment, the compressed air energy storage expansion system workflow includes:

[0108] The system first stores the compressed air in the high-pressure gas storage A. The high-pressure gas storage A can withstand high pressure to store a large amount of compressed air. Before the energy release begins, the quick-closing valve 1, the regulating valve 5, and the air supply valve 4 are in the closed state.

[0109] When the stored compressed air needs to be released, the quick-closing valve is opened, and the compressed air in the high-pressure gas storage reservoir A is heated by the heat exchanger B and then enters the variable pressure expander C to expand and do work. The exhaust of the variable pressure expander C enters the constant pressure expander E to do work.

[0110] After passing through the quick-closing valve, the compressed air enters the cold side inlet of heat exchanger B. Here, the compressed air can be heated to improve the expansion efficiency. The heated compressed air flows out from the cold side outlet of heat exchanger B and enters the variable pressure expander C.

[0111] The variable pressure expander C uses the pressure energy of compressed air to expand and convert it into mechanical energy. The output shaft of the variable pressure expander C is connected to the generator D, and the mechanical energy of the expander is converted into electrical energy, which is used or stored in the power grid.

[0112] The inlet of the constant pressure expander E is connected to the outlet of the variable pressure expander C and the air supply valve 4. Its function is to further expand the compressed air after the variable pressure expander C to improve the efficiency of the whole system.

[0113] In order to maintain the stable operation of the system and optimize the performance, the air supply valve 4 can supply air to the system as needed. The air supply valve 4 can adjust the opening according to the actual operation of the system. The regulating valve 5 is used to further finely control the flow of compressed air entering the variable pressure expander C to adapt to different working conditions.

[0114] Based on Example 1, Figure 1 As shown, the working process of the compressed air energy storage expansion system is as follows:

[0115] During the energy release process, the pressure at the outlet of the high-pressure gas storage reservoir A begins to gradually decrease, and the inlet pressure of the variable pressure expander C also gradually decreases, and the inlet volume flow rate increases. If the first-stage blades cannot meet the flow of the volume flow rate, the opening of the regulating valve 5 of the first-stage bypass flow path b is increased, and air is supplemented at the exhaust position of the first-stage blades to meet the flow requirements. At the same time, the exhaust pressure of the first-stage blades is kept constant, and the blades of all subsequent stages still work at the design point, and their flow efficiency is relatively high. The opening of the air supplement valve 4 is adjusted synchronously to increase the flow of the constant pressure expander E to ensure that the total output power of the expansion system remains unchanged.

[0116] When the pressure at the outlet of the high-pressure gas storage reservoir A continues to drop, and the exhaust pressure of the first-stage blade cannot be maintained, the opening of the regulating valve 5 corresponding to the first-stage blade is gradually closed, and the opening of the regulating valve 5 of the second-stage bypass flow path c is increased, and air is supplemented at the exhaust position of the second-stage blade to meet the flow requirements. At the same time, the exhaust pressure of the second-stage blade is kept constant, and the blades of all subsequent stages still work at the design point, and their flow efficiency is relatively high. The opening of the air supplement valve 4 is adjusted synchronously to increase the flow of the constant pressure expander E to ensure that the total output power of the expansion system remains unchanged.

[0117] The operations of other stage blades are similar. If the stage blade is the Nth stage blade (i.e. the last stage blade), the opening of the air supply valve 4 is directly adjusted to ensure that the exhaust pressure of the variable pressure expander C remains constant and the total output power of the expansion system remains unchanged.

[0118] The present application adopts a step-by-step bypass method so that the variable pressure expander C meets the requirements of the compressed air energy storage expansion system and effectively solves the problem caused by the step-by-step reduction of the intake pressure.

[0119] Example 12

[0120] The present application also provides a control method, including:

[0121] S10, in response to the acquired operation instruction, controlling the compressed air in the high-pressure gas storage reservoir A to expand and perform work. The operation instruction is an instruction for starting energy release.

[0122] Specifically, when energy release begins, the quick-closing valve 1 is opened, and the compressed air in the high-pressure gas storage reservoir A is heated by the heat exchanger B and then enters the variable pressure expander C to expand and do work. The exhaust of the variable pressure expander C enters the constant pressure expander E to do work.

[0123] S20. Obtain a first parameter, wherein the first parameter is used to characterize an intake pressure Pc of the variable pressure expander, wherein during the energy release process, the intake pressure Pc will continue to decrease.

[0124] S30, obtaining a second parameter, wherein the second parameter is used to characterize the pressure at the outlet position of each stage of the blades, the pressure after the first stage of blades is P1 ... the pressure after the nth stage of blades is Pn.

[0125] S40: Determine a target blade level based on the first parameter and the second parameter.

[0126] S50, based on the target blade level, changing the opening of the valve assembly, wherein the position of the valve assembly corresponds to the position of the target blade level. By changing the opening of the valve assembly, a portion of the gas is put into the blades of the next stage, and the blades of the next stage can flow through with a small mass flow rate, while the blades of the next stage still flow through with the original mass flow rate.

[0127] The determining a target blade level based on the first parameter and the second parameter includes:

[0128] S501, determining a reference parameter based on the second parameter and a target expansion ratio;

[0129] S502, comparing the reference parameter and the first parameter;

[0130] S503. Determine the target blade level based on the comparison result. Specifically, the present application determines the reference parameter Px through the second parameter P1...Pn and the target expansion ratio Pr, that is, the reference parameter Px=P1*Pr, Px=P2*Pr...Px=Pn*Pr, wherein the target expansion ratio Pr is the minimum expansion ratio, and the expansion ratio is set according to the design and use conditions. Then compare the reference parameter Px with the intake pressure Pc, and determine the target blade level according to the comparison result.

[0131] During the energy release process, the pressure at the outlet of the high-pressure gas storage reservoir A begins to decrease gradually, and the ability of each blade stage inside the pressure variable expander C to allow gas to flow through will not be able to meet the requirements step by step. When the ability of the blade stage to allow gas to flow through is insufficient, if the blade stage is not the last stage, the opening of the regulating valve 5 of the bypass pipe 6 of the blade stage is adjusted to ensure that the exhaust pressure of the blade stage is maintained constant, then the blades of all subsequent stages still work in the high-efficiency zone, and the opening of the air supply valve 4 is adjusted synchronously to ensure that the total output power of the expansion system remains unchanged.

[0132] If this stage is the last stage blade, the opening of the air supply valve 4 is directly adjusted to ensure that the exhaust pressure of the variable pressure expander C remains constant and the total output power of the expansion system remains unchanged.

[0133] As the pressure at the outlet of the high-pressure gas storage reservoir A further decreases, if the regulating valve 5 and the air supply valve 4 of the entire expander system are fully opened and the exhaust pressure of the variable pressure expander C cannot be maintained at the design value, the energy release is terminated.

[0134] Specifically, as the intake pressure Pc gradually decreases, the opening of the valve assembly corresponding to the first-stage blade is first changed, and the pressure P1 after the first-stage blade is maintained unchanged by increasing the valve opening of the regulating valve 5. In addition, the opening of the air supply valve 4 is increased synchronously to ensure that the total power generation of the variable pressure expander C and the constant pressure expander E remains unchanged.

[0135] If the intake pressure Pc is lower than the pressure P1 after the first-stage blades*the target expansion ratio Pr, it is determined that the target blade stage is the second-stage blades, and the opening of the regulating valve 5 corresponding to the first-stage blades is gradually closed, and at the same time, the opening of the regulating valve 5 corresponding to the second-stage blades is gradually increased to ensure that the pressure P2 after the second-stage blades remains unchanged. In addition, the opening of the air supply valve 4 is synchronously increased to ensure that the total power generation of the variable pressure expander C and the constant pressure expander E remains unchanged.

[0136] If the intake pressure Pc is lower than the pressure P2 after the second-stage blades*the target expansion ratio Pr, it is determined that the target blade stage is the third-stage blades, and the opening of the regulating valve 5 corresponding to the second-stage blades is gradually closed, and at the same time, the opening of the regulating valve corresponding to the third-stage blades is gradually increased. In addition, the opening of the air supply valve 4 is increased synchronously to ensure that the total power generation of the variable pressure expander C and the constant pressure expander E remains unchanged.

[0137] Similarly, if the target blade level is not the last blade level, follow the above operations in sequence. If the target blade level is the last blade level, directly increase the opening of the air supply valve 4 to ensure that the pressure Pn after the last blade level remains unchanged, thereby ensuring that the total power generation power of the variable pressure expander C and the constant pressure expander E remains unchanged.

[0138] If the intake pressure Pc is lower than the pressure Pn after the nth stage blade*the target expansion ratio Pr, the operation ends.

[0139] The opening of the air supply valve 4 has nothing to do with the opening of the regulating valve 5. The opening of the air supply valve 4 is related to the total power generation of the expansion system. If it is too small, the opening is increased, and if it is too large, the opening is decreased.

[0140] For example, during the energy release process, the intake pressure of the variable pressure expander C, 12.95 MPa, gradually decreases. As the intake pressure decreases, the gas density at the intake position decreases and the intake volume flow rate increases.

[0141] If the ability of the first-stage blades to allow gas to flow through cannot meet the volume flow rate, the opening of the regulating valve 5 of the first-stage bypass pipe b6 is increased, and air is supplemented at the exhaust position of the first-stage blades to meet the flow requirement. At the same time, the exhaust pressure of the first-stage blades is maintained constant at 8.6MPA. Then, the blades of all subsequent stages still work at the design point, and their flow efficiency is relatively high. The opening of the air supplement valve 4 is adjusted synchronously to increase the flow of the subsequent stage expander to ensure that the total output power of the expansion system remains unchanged.

[0142] When the inlet pressure of the variable pressure expander C continues to drop below 9.16MPA (assuming the minimum expansion ratio is 1.1), the exhaust pressure of the first-stage blade cannot be maintained at 8.6MPa, and the opening of the regulating valve 5 of the first-stage bypass pipe b6 is gradually closed, and the opening of the regulating valve 5 of the second-stage bypass pipe c6 is increased, and air is supplemented at the exhaust position of the second-stage blade to meet the flow requirements, while ensuring that the exhaust pressure of the second-stage blade is kept constant at 5.7MPa, then all the blades of the subsequent stages still work at the design point, and their flow efficiency is relatively high, and the opening of the air supplement valve 4 is adjusted synchronously to increase the flow of the subsequent stage expander to ensure that the total output power of the expansion system remains unchanged. The other stage blades are operated similarly.

[0143] If the blades at this stage are the last stage blades, the opening of the air supply valve 4 is directly adjusted to ensure that the exhaust pressure of the variable pressure expander C is kept constant at 2.5 MPa and the total output power of the expansion system remains unchanged.

[0144] As the inlet pressure of the variable pressure expander C further decreases and the exhaust pressure of the variable pressure expander C cannot be maintained at the design value of 2.5 MPA, the energy release is terminated.

[0145] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present application within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present application.

Claims

1. A variable pressure expander, characterized in that: include: An inner casing, comprising an inlet and an outlet, wherein the inner wall of the inner casing is provided with a plurality of stationary blades evenly distributed along the axial direction thereof; A rotating shaft, which is rotatably arranged on the inner axis of the inner shell, a plurality of moving blades evenly distributed along the axis direction thereof are arranged on the outer wall of the rotating shaft, a plurality of the stationary blades and a plurality of the moving blades are staggered, adjacent stationary blades and moving blades form a group of blade stages, and a blade stage gap is formed between adjacent blade stages, wherein the multiple blade stages are divided into first-stage blades, second-stage blades, ..., N-1-stage blades and N-stage blades; An outer shell is arranged outside the inner shell, and a plurality of bypass pipes are arranged on the outer shell. The plurality of bypass pipes penetrate the outer shell and are respectively connected with corresponding blade stage gaps, and regulating valves are respectively arranged on the bypass pipes; As the intake pressure at the inlet gradually decreases, the opening of the regulating valve corresponding to the first-stage blade is first changed, and the pressure after the first-stage blade is ensured to remain unchanged by increasing the valve opening of the regulating valve; If the intake pressure at the inlet is lower than the pressure after the first-stage blade*target expansion ratio, the target blade stage is determined to be the second-stage blade, and the opening of the regulating valve corresponding to the first-stage blade is gradually closed, and at the same time, the valve opening of the regulating valve corresponding to the second-stage blade is gradually increased to ensure that the pressure after the second-stage blade remains unchanged; If the target blade level is not the last blade level, perform the above operations in sequence.

2. The pressure variable expander according to claim 1, characterized in that: A cavity is formed between the inner wall of the outer shell and the outer wall of the inner shell, and a plurality of first partitions are arranged in the cavity to divide the cavity into a plurality of connecting cavities corresponding to the blade stage gaps respectively. The air outlet end of the bypass pipe is communicated with the inlet of the corresponding connecting cavity, and the outlet of the connecting cavity is communicated with the corresponding blade stage gap, so that the bypass pipe is communicated with the corresponding blade stage gap through the corresponding connecting cavity.

3. The pressure variable expander according to any one of claims 1 to 2, characterized in that: The inlet of the inner shell is arranged on the outer peripheral wall thereof, and the variable pressure expander further comprises: A bypass chamber is arranged on the outside of the outer shell, the bypass chamber includes an inlet and multiple outlets, the outlets of the bypass chamber are respectively connected to the bypass pipeline and the main gas pipeline, the main gas pipeline is connected to the inlet of the inner shell, and a regulating valve for opening and closing the bypass pipeline is provided in the bypass chamber.

4. The pressure variable expander according to claim 1, characterized in that: A cavity is formed between the inner wall of the outer shell and the outer wall of the inner shell, the bypass pipe is embedded in the inner wall of the inner shell, and the inlet of the cavity is communicated with the inlet of the inner shell.

5. The pressure variable expander according to claim 2, characterized in that: A second partition is provided in the cavity to divide the cavity into a first inner cavity and a second inner cavity, and a plurality of evenly distributed first partitions are provided in the second inner cavity to divide the second inner cavity into a plurality of connecting cavities corresponding to the blade stage gaps, respectively. The bypass pipe is embedded in the second partition plate, and the inlet of the inner shell is communicated with the inlet of the cavity.

6. The pressure variable expander according to claim 5, characterized in that: The inlet of the inner shell is arranged on its outer peripheral wall, and the outer shell is provided with a main gas pipeline, which is communicated with the inlet of the inner shell through the first inner cavity.

7. The pressure variable expander according to any one of claims 1 to 2, characterized in that: The bypass pipe is arranged on the outer peripheral wall of the outer shell or on the end surface of the outer shell.

8. A compressed air energy storage expansion system, characterized in that: The method comprises the pressure variable expander according to any one of claims 1 to 7, further comprising: A high-pressure gas storage reservoir, the gas outlet of which is connected to the gas inlet of the quick-closing valve; A heat exchanger, wherein the cold side inlet is connected to the gas outlet of the quick-closing valve, and the cold side outlet is respectively connected to the gas supply valve, the regulating valve and the inlet of the variable pressure expander; a generator connected to the output shaft of the variable pressure expander to generate electricity at the output of the variable pressure expander; The inlet of the constant pressure expander is connected to the outlet of the variable pressure expander and the air supply valve respectively.

9. A control method, applied to the pressure variable expander according to any one of claims 1 to 7, characterized in that: include: In response to the acquired operation instruction, controlling the compressed air in the high-pressure gas storage to expand and perform work; Acquire a first parameter, wherein the first parameter is used to characterize the intake pressure of the variable pressure expander; Acquire a second parameter, wherein the second parameter is used to characterize the pressure at the air outlet position of each stage of blades; determining a target blade level based on the first parameter and the second parameter; Based on the target blade level, the opening degree of the regulating valve is changed, wherein the position of the regulating valve corresponds to the position of the target blade level.

10. The control method according to claim 9, wherein determining the target blade level based on the first parameter and the second parameter comprises: determining a reference parameter based on the second parameter and the target expansion ratio; comparing the reference parameter and the first parameter; Based on the comparison result, the target blade level is determined.

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