Interstage load grid connection device and method for multistage centrifugal compressor
By adopting an inlet and outlet air passage structure in a multi-stage centrifugal compressor, and combining check valves and valves to control airflow, the problem of airflow interference during inter-stage load grid connection of a multi-stage centrifugal compressor is solved, achieving stable grid connection and reducing equipment costs and energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHENYANG BLOWER GRP GEAR COMPRESSOR
- Filing Date
- 2026-03-09
- Publication Date
- 2026-04-21
AI Technical Summary
Existing technologies make it difficult to achieve stable grid connection of interstage loads in multi-stage centrifugal compressors, especially when a common drying structure is used, as the risk of mutual airflow interference is high, affecting the stability of the device.
The system employs a multi-stage centrifugal compressor interstage load grid connection device, including an intake channel and an exhaust channel structure, combined with a check valve and valve structure, to achieve independent control and coordinated management of the two units. By adjusting the valve structure, the airflow is controlled, reducing pressure and airflow interference during the grid connection process.
It enables stable grid connection of interstage loads of multi-stage centrifugal compressors, improves the success rate of operation and system safety, and reduces equipment costs, floor space and energy consumption.
Smart Images
Figure CN121897592A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of compressor technology, and in particular to a multi-stage centrifugal compressor interstage load grid connection device and method. Background Technology
[0002] With advancements in centrifugal compressor control technology, the demands on equipment cost and space are increasing, leading to greater control complexity. Taking CO2 as an example, its water content reacts to form carbonic acid, causing continuous corrosion to pipes and compressors. Therefore, installing a drying structure between compressor stages is an effective solution. For two units, sharing a single drying structure saves space and cost. However, this shared structure increases grid connection difficulty. The low- and medium-pressure airflows from both units enter the same interstage structure, and the exhaust gas from the interstage structure enters the high-pressure compression section for further pressurization. Improper operation can easily lead to mutual airflow interference. Existing methods struggle to achieve stable gas grid connection and distribution, affecting the stability of the unit.
[0003] Therefore, there is currently a lack of a device and method that can adapt to the shared drying stage structure and achieve stable grid connection of interstage loads in multi-stage centrifugal compressors. Summary of the Invention
[0004] In view of this, the present invention provides a multi-stage centrifugal compressor interstage load grid connection device.
[0005] Specifically, the following technical solutions are included: In a first aspect, a multi-stage centrifugal compressor interstage load grid connection device includes: a first unit, a second unit, an interstage structure, and a channel structure; The first unit includes a first medium-low pressure compression section and a first high pressure compression section, and the second unit includes a second medium-low pressure compression section and a second high pressure compression section. The first medium-low pressure compression section and the second medium-low pressure compression section are connected in parallel, and the first high pressure compression section and the second high pressure compression section are connected in parallel. The channel structure includes an intake channel structure and an exhaust channel structure. The first medium-low pressure compression section and the second medium-low pressure compression section are connected to the interstage structure through the intake channel structure, and the first high pressure compression section and the second high pressure compression section are connected to the interstage structure through the exhaust channel structure.
[0006] Furthermore, the air intake channel structure includes an air intake inlet end and an air intake outlet end; The air inlet is provided in two parts: one air inlet is connected to the first medium-low pressure compression section, and the other air inlet is connected to the second medium-low pressure compression section. The air inlet / outlet end is connected to the interstage structure.
[0007] Furthermore, the air outlet channel structure includes an air outlet inlet end and an air outlet end; Two air outlets are provided, one of which is connected to the first high-pressure compression section, and the other is connected to the second high-pressure compression section. The air inlet end is connected to the interstage structure.
[0008] Furthermore, the device includes a first check valve, a second check valve, a third check valve, and a fourth check valve; The first check valve is installed on the intake passage structure that connects the first medium-low pressure compression section and the interstage structure; The second check valve is installed on the intake passage structure that connects the second medium-low pressure compression section and the interstage structure; The third check valve is installed on the outlet channel structure connecting the first high-pressure compression section and the interstage structure; The fourth check valve is installed on the outlet passage structure that connects the second high-pressure compression section and the interstage structure.
[0009] Furthermore, the device also includes a first valve structure and a second valve structure; The first valve structure is disposed on the intake passage structure connecting the first medium-low pressure compression section and the interstage structure, and the first valve structure is used to control the on / off state of the first medium-low pressure compression section and the interstage structure. The second valve structure is disposed on the intake passage structure connecting the second medium-low pressure compression section and the interstage structure, and the second valve structure is used to control the on / off state of the second medium-low pressure compression section and the interstage structure.
[0010] Furthermore, the device also includes a third valve structure and a fourth valve structure; The third valve structure is disposed on the outlet channel structure connecting the first high-pressure compression section and the interstage structure, and the third valve structure is used to control the flow rate of the first high-pressure compression section and the interstage structure; The fourth valve structure is installed on the outlet channel structure connecting the second high-pressure compression section and the interstage structure, and the fourth valve structure is used to control the flow rate of the second high-pressure compression section and the interstage structure.
[0011] Furthermore, the interstage structure is a dry structure.
[0012] Furthermore, the drying structure includes at least one molecular sieve dehydration tower.
[0013] Furthermore, the interstage structure is provided with a detection structure, which is used to detect the pressure and temperature within the interstage structure.
[0014] In a second aspect, a method for controlling the interstage load of a multi-stage centrifugal compressor via grid connection is provided, employing a multi-stage centrifugal compressor interstage load grid connection device as described in the first aspect. The method includes: controlling the operation of the first unit and / or the second unit; controlling the first medium-low pressure compression section and / or the second medium-low pressure compression section to be connected to the interstage structure through the intake channel structure; the exhaust gas in the first medium-low pressure compression section and / or the second medium-low pressure compression section entering the interstage structure through the intake channel; and controlling the first high pressure compression section and / or the second high pressure compression section to be connected to the interstage structure through the exhaust channel structure; the gas in the interstage structure entering the first high pressure compression section and / or the second high pressure compression section through the exhaust channel structure.
[0015] The beneficial effects of the technical solution provided by this invention include at least the following: The application proposes to control the airflow of the channel structure by adjusting the valve structure, so that the interstage structure can smoothly enter or exit air, reduce the pressure and airflow interference during the grid connection process of the interstage structure, improve the success rate of operation and system safety, and reduce equipment costs, floor space and energy consumption due to the common interstage structure. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram illustrating the working principle of a multi-stage centrifugal compressor interstage load grid connection device according to an embodiment of the present invention.
[0018] The reference numerals in the figure are respectively: 1. First unit; 11. First medium-low pressure compression section; 12. First high pressure compression section; 2. Second unit; 21. Second medium-low pressure compression section; 22. Second high pressure compression section; 3. Interstage structure; 41. Inlet passage structure; 411. Inlet end; 412. Inlet outlet end; 42. Outlet passage structure; 421. Outlet inlet end; 422. Outlet outlet end; 51. First check valve; 52. Second check valve; 53. Third check valve; 54. Fourth check valve; 55. First valve structure; 56. Second valve structure; 57. Third valve structure; 58. Fourth valve structure.
[0019] The accompanying drawings illustrate specific embodiments of the invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation
[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0021] Before providing a further detailed description of the embodiments of the present invention, the directional terms used in the embodiments of the present invention, such as "upper part," "lower part," and "side part," are used to refer to... Figure 1 The orientation shown is a reference and does not limit the scope of protection of this invention.
[0022] To make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
[0023] like Figure 1 As shown, a multi-stage centrifugal compressor interstage load grid-connected device includes a first unit 1, a second unit 2, an interstage structure 3, and a channel structure. The first unit 1 includes a first medium-low pressure compression section 11 and a first high pressure compression section 12. The second unit 2 includes a second medium-low pressure compression section 21 and a second high pressure compression section 22. The first medium-low pressure compression section 11 and the second medium-low pressure compression section 21 are connected in parallel, and the first high pressure compression section 12 and the second high pressure compression section 22 are connected in parallel. The channel structure includes an intake channel structure 41 and an outlet channel structure 42. The first medium-low pressure compression section 11 and the second medium-low pressure compression section 21 are connected to the interstage structure 3 through the intake channel structure 41, and the first high pressure compression section 12 and the second high pressure compression section 22 are connected to the interstage structure 3 through the outlet channel structure 42.
[0024] This application discloses a multi-stage centrifugal compressor interstage load grid connection device, which aims to enable two independent multi-stage centrifugal compressor units to be connected into a shared interstage structure 3, thereby reducing the oscillation caused by grid connection through flexible allocation.
[0025] This device comprises a first unit 1, a second unit 2, an interstage structure 3, and a channel structure. The first unit 1 is divided into a first low-to-medium pressure compression section 11 and a first high-pressure compression section 12. The second unit 2 is divided into a second low-to-medium pressure compression section 21 and a second high-pressure compression section 22. The first low-to-medium pressure compression section 11 and the second low-to-medium pressure compression section 21 are connected to the interstage structure 3 via an intake channel structure 41. In summary, the first low-to-medium pressure compression section 11 and the second low-to-medium pressure compression section 21 are connected in parallel, and they share the compressed gas in the same interstage structure 3. The first high-pressure compression section 12 and the second high-pressure compression section 22 are connected to the interstage structure 3 via an outlet channel structure 42. In summary, the first high-pressure compression section 12 and the second high-pressure compression section 22 are also connected in parallel, and they draw gas from the same interstage structure 3 for further compression, then discharge the final gas into the downstream device. This device, through the parallel and series unit configuration, achieves independent control and coordinated management of the two units.
[0026] In one embodiment, the first medium-low pressure compression section 11 and the second medium-low pressure compression section 21 are both composed of 1 to 6 compression stages.
[0027] In one embodiment, both the first high-pressure compression section 12 and the second high-pressure compression section 22 are composed of 7 to 8 compression stages.
[0028] like Figure 1 As shown, the intake channel structure 41 includes an intake inlet end 411 and an intake outlet end 412. Two intake inlets 411 are provided. One intake inlet end 411 is connected to the first medium-low pressure compression section 11, and the other intake inlet end 411 is connected to the second medium-low pressure compression section 21. The intake outlet end 412 is connected to the interstage structure 3.
[0029] The intake passage structure 41 includes an intake inlet end 411 and an intake outlet end 412. One intake inlet end 411 is connected to the exhaust port of the first medium-low pressure compression section 11 of the first unit 1. The other intake inlet end 411 is connected to the exhaust port of the second medium-low pressure compression section 21 of the second unit 2. These two intake inlet ends 411 are symmetrically arranged. The intake passage structure 41 also has two intake outlet ends 412, and the outlet ends of the intake passage structure 41 are all connected to the interstage structure 3.
[0030] like Figure 1 As shown, the air outlet channel structure 42 includes an air outlet inlet end 421 and an air outlet end 422. Two air outlet inlets 421 are provided. One air outlet inlet end 421 is connected to the first high-pressure compression section 12, and the other air outlet inlet end 421 is connected to the second high-pressure compression section 22. The air inlet end 411 is connected to the interstage structure 3.
[0031] The exhaust passage structure 42 includes an exhaust inlet end 421 and an exhaust outlet end 422. The first exhaust outlet end 422 is connected to the air inlet of the first high-pressure compression section 12 of the first unit 1. The second exhaust outlet end 412 is connected to the air inlet of the second high-pressure compression section of the second unit 2. The second exhaust outlet end 422 is symmetrically arranged with the first exhaust outlet end 422. The exhaust passage structure 42 also has two exhaust inlet ends 421, both of which are connected to the interstage structure 3.
[0032] like Figure 1 As shown, the device includes a first check valve 51, a second check valve 52, a third check valve 53, and a fourth check valve 54. The first check valve 51 is disposed on the intake channel structure 41 connecting the first medium-low pressure compression section 11 and the interstage structure 3. The second check valve 52 is disposed on the intake channel structure 41 connecting the second medium-low pressure compression section 21 and the interstage structure 3. The third check valve 53 is disposed on the outlet channel structure 42 connecting the first high pressure compression section 12 and the interstage structure 3. The fourth check valve 54 is disposed on the outlet channel structure 42 connecting the second high pressure compression section 22 and the interstage structure 3.
[0033] A first check valve 51 is installed in series on the intake passage structure 41, located after the intake inlet 411 and before the intake outlet 412 of the first medium-low pressure compression section 11. A second check valve 52 is installed in series on the intake passage structure 41, located after the intake inlet 411 and before the intake outlet 412 of the second medium-low pressure compression section 21. These two check valves work together to prevent high-pressure gas from flowing back into the operating medium-low pressure compression section when the pressure in the interstage structure 3 rises abnormally.
[0034] A third check valve 53 is installed in series on the outlet passage structure 42, located after the outlet inlet 421 and before the outlet 422 of the first high-pressure compression section 12. A fourth check valve 54 is installed in series on the outlet passage structure 42, located after the outlet inlet 421 and before the outlet 422 of the second high-pressure compression section 22. These two check valves work together to prevent cross-flow between the two high-pressure compression sections and to control pressure. The check valves isolate the two high-pressure compression sections from the interstage structure 3, ensuring independent operation of each unit.
[0035] like Figure 1As shown, the device further includes a first valve structure 55 and a second valve structure 56. The first valve structure 55 is disposed on the intake passage structure 41 connecting the first medium-low pressure compression section 11 and the interstage structure 3, and the first valve structure 55 is used to control the on / off state of the first medium-low pressure compression section 11 and the interstage structure 3. The second valve structure 56 is disposed on the intake passage structure 41 connecting the second medium-low pressure compression section 21 and the interstage structure 3, and the second valve structure 56 is used to control the on / off state of the second medium-low pressure compression section 21 and the interstage structure 3.
[0036] The first valve is installed in series on the intake passage structure 41, located after the intake inlet end 411 and before the intake outlet end 412 of the first medium-low pressure compression section 11. It acts as an isolating switch for the first unit 1 and can control the physical connection and disconnection between the first medium-low pressure compression section 11 and the interstage structure 3. The first valve structure 55 and the first check valve 51 are connected in series, with the first check valve 51 located upstream of the first valve structure 55.
[0037] The second valve structure 56 is installed symmetrically to the first valve structure 55. It is mounted on the intake passage structure 41, located after the intake inlet 411 and before the intake outlet 412 of the second medium-low pressure compression section 21. As an isolating switch for the second unit 2, it controls the physical connection and disconnection between the second medium-low pressure compression section 21 and the interstage structure 3. The second valve structure 56 and the second check valve 52 are connected in series, with the second check valve 52 located upstream of the second valve structure 56.
[0038] In one embodiment, both the first valve structure 55 and the second valve structure 56 are shut-off valves.
[0039] like Figure 1 As shown, the device further includes a third valve structure 57 and a fourth valve structure 58. The third valve structure 57 is disposed on the outlet passage structure 42 connecting the first high-pressure compression section 12 and the interstage structure 3, and is used to control the flow rate of the first high-pressure compression section 12 and the interstage structure 3. The fourth valve structure 58 is disposed on the outlet passage structure 42 connecting the second high-pressure compression section 22 and the interstage structure 3, and is used to control the flow rate of the second high-pressure compression section 22 and the interstage structure 3.
[0040] The third valve structure 57 is installed on the outlet passage, located after the outlet inlet 421 of the passage structure and before the outlet 422 of the first high-pressure compression section 12. As the flow control valve of the first unit 1, it can control the airflow between the first high-pressure compression section and the interstage structure 3. The third valve structure 57 and the third check valve 53 are connected in series, with the third check valve 53 located upstream of the third valve structure 57.
[0041] The fourth valve structure 58 is installed on the outlet passage, located after the outlet inlet 421 of the passage structure and before the outlet 422 of the second high-compression section. As the flow control valve for the second unit 2, it controls the airflow between the second high-compression section and the interstage structure 3. The fourth valve structure 58 and the fourth check valve 54 are connected in series, with the fourth check valve 54 located upstream of the fourth valve structure 58.
[0042] In one embodiment, both the third valve structure 57 and the fourth valve structure 58 are pressure regulating valves.
[0043] like Figure 1 As shown, the interstage structure 3 is a drying structure.
[0044] like Figure 1 As shown, the drying structure includes at least one molecular sieve dehydration tower.
[0045] like Figure 1 As shown, a detection structure is provided in the interstage structure 3, which is used to detect the pressure and temperature within the interstage structure 3.
[0046] The detection structure refers to the sensor installed on the body of the interstage structure 3. Its function is to display the internal status of the interstage structure 3 in real time. It can provide operators with information about the internal structure of the interstage structure 3, such as comparing the current pressure value and temperature of the interstage structure 3 with preset pressure and temperature ranges to determine whether the interstage structure 3 is operating normally.
[0047] In one embodiment, the detection structure is a pressure gauge and a temperature instrument.
[0048] like Figure 1 As shown, the operation of the first unit 1 and / or the second unit 2 is controlled; The first low-pressure compression section 11 and / or the second low-pressure compression section 21 are connected to the interstage structure 3 through the intake channel structure 41. The exhaust gas in the first low-pressure compression section 11 and / or the second low-pressure compression section 21 enters the interstage structure 3 through the intake channel. The first high-pressure compression section 12 and / or the second high-pressure compression section 22 are connected to the interstage structure 3 through the exhaust channel structure 42. The gas in the interstage structure 3 enters the first high-pressure compression section 12 and / or the second high-pressure compression section 22 through the exhaust channel structure 42.
[0049] In one embodiment, only one of the first unit 1 and the second unit 2 is started. Taking the first unit 1 as an example, the first unit 1 is started to a preset pressure, and the first medium-low pressure compression section 11 is controlled to connect with the interstage structure 3 through the intake channel structure 41. The exhaust gas from the first medium-low pressure compression section 11 enters the interstage structure 3 through the intake channel. The first high pressure compression section 12 is controlled to connect with the interstage structure 3 through the exhaust channel structure 42. The gas in the interstage structure 3 enters the first high pressure compression section 12 through the exhaust channel structure 42, and the exhaust gas from the first high pressure compression section 12 is connected to the grid.
[0050] In one embodiment, both the first unit 1 and the second unit 2 are started. The first unit 1 and the second unit 2 are controlled to start operating simultaneously, and the pressure in the first unit 1 and the second unit 2 is brought to a preset pressure. The first low-pressure compression section 11 and the second low-pressure compression section 21 are controlled to connect with the interstage structure 3 through the intake channel structure 41, and the exhaust gas from the first low-pressure compression section 11 and the second low-pressure compression section 21 simultaneously enters the interstage structure 3 through the intake channel. The first high-pressure compression section 12 and the second high-pressure compression section 22 are controlled to connect with the interstage structure 3 through the exhaust channel structure 42, and the gas in the interstage structure 3 simultaneously enters the first high-pressure compression section 12 and the second high-pressure compression section 22 through the exhaust channel structure 42. The exhaust gas from the first high-pressure compression section 12 and the second high-pressure compression section 22 is then connected to the grid.
[0051] In one embodiment, when one of the first unit 1 and the second unit 2 is in operation, the other unit needs to be started. Taking the first unit 1 being in operation and the second unit 2 needing to be started as an example, the second high-pressure compression section 22 is connected to the outlet channel structure 42 of the interstage structure 3, and the opening degree of the second high-pressure compression section 22 and the outlet channel structure 42 of the interstage structure 3 is a first opening degree; the second unit 2 is started, and the second medium-low pressure compression section 21 is operated, so that the output pressure of the second medium-low pressure compression section 21 matches the pressure of the interstage structure 3, and the opening degree of the second high-pressure compression section 22 and the outlet channel structure 42 of the interstage structure 3 is increased so that the intake volume of the second high-pressure compression section 22 meets the preset intake conditions; the medium-low pressure compression section of the second unit 2 is connected to the intake channel structure 41 of the interstage structure 3, so that the gas of the second unit 2 flows into the interstage structure 3.
[0052] Specifically, the usage process of this device is as follows: First, Unit 1 is the already operational unit, and Unit 2 is the unit to be started. The connection channels between Unit 2 and Interstage Structure 3 are isolated. Unit 1 operates independently. Gas discharged from the first low-pressure compression section 11 enters Interstage Structure 3 through the intake channel structure 41. Gas discharged from Interstage Structure 3 enters the first high-pressure compression section 12 through the outlet channel for compression before being transported outwards. At this time, the monitoring structure of Interstage Structure 3 displays approximately 7.1 MPaG.
[0053] Second, open the fourth valve structure 58, with the opening degree around 1%~2%, and inject gas into the second high-pressure compression section 22.
[0054] Third, start the second medium-low pressure compression section 21 of the second unit 2 to match the outlet pressure of the second medium-low pressure compression section 21 with the pressure of the interstage structure 3. At the same time, increase the opening of the second high pressure compression section 22 and the outlet passage structure 42 of the interstage structure 3 so that the intake volume of the second high pressure compression section 22 meets the preset intake conditions. The opening increases as the inlet pressure of the second high pressure compression section 22 increases.
[0055] Fourth, open the second valve structure 56 to control the connection between the second medium-low pressure compression section 21 and the air intake channel structure 41 of the interstage structure 3, so that the gas in the second medium-low pressure compression section 21 enters the interstage structure 3.
[0056] Fifth, adjust the third valve structure 57 and the fourth valve structure 58. The interstage structure 3 is connected to the first high-pressure compression section 12 and the second high-pressure compression section 22, so that the gas from the two units is connected to the grid through the interstage structure 3.
[0057] Sixth, by adjusting the valve structure of the first unit 1 and the second unit 2, the device achieves pressure and flow balance to complete the inter-stage load grid connection.
[0058] The application controls the airflow of the channel structure by adjusting the valve structure, allowing the interstage structure 3 to smoothly intake or exhaust air, reducing pressure and airflow interference during grid connection of the interstage structure 3, improving operational success rate and system safety, and reducing equipment cost, floor space, and energy consumption due to the shared interstage structure 3. In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.
[0059] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.
[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A multi-stage centrifugal compressor interstage load grid connection device, characterized in that, include: Unit 1, Unit 2, interstage structure, and passageway structure; The first unit includes a first medium-low pressure compression section and a first high pressure compression section, and the second unit includes a second medium-low pressure compression section and a second high pressure compression section. The first medium-low pressure compression section and the second medium-low pressure compression section are connected in parallel, and the first high pressure compression section and the second high pressure compression section are connected in parallel. The channel structure includes an intake channel structure and an exhaust channel structure. The first medium-low pressure compression section and the second medium-low pressure compression section are connected to the interstage structure through the intake channel structure, and the first high pressure compression section and the second high pressure compression section are connected to the interstage structure through the exhaust channel structure.
2. The grid-connected device for interstage load of a multi-stage centrifugal compressor according to claim 1, characterized in that, The air intake channel structure includes an air intake inlet end and an air intake outlet end; The air inlet is provided in two parts: one air inlet is connected to the first medium-low pressure compression section, and the other air inlet is connected to the second medium-low pressure compression section. The air inlet / outlet end is connected to the interstage structure.
3. The grid-connected device for interstage load of a multi-stage centrifugal compressor according to claim 1, characterized in that, The air outlet channel structure includes an air outlet inlet end and an air outlet end; Two air outlets are provided, one of which is connected to the first high-pressure compression section, and the other is connected to the second high-pressure compression section. The air inlet end is connected to the interstage structure.
4. The grid-connected device for interstage load of a multi-stage centrifugal compressor according to claim 1, characterized in that, The device includes a first check valve, a second check valve, a third check valve, and a fourth check valve; The first check valve is installed on the intake passage structure that connects the first medium-low pressure compression section and the interstage structure; The second check valve is installed on the intake passage structure that connects the second medium-low pressure compression section and the interstage structure; The third check valve is installed on the outlet channel structure connecting the first high-pressure compression section and the interstage structure; The fourth check valve is installed on the outlet passage structure that connects the second high-pressure compression section and the interstage structure.
5. The grid-connected device for interstage load of a multi-stage centrifugal compressor according to claim 1, characterized in that, The device also includes a first valve structure and a second valve structure; The first valve structure is disposed on the intake passage structure connecting the first medium-low pressure compression section and the interstage structure, and the first valve structure is used to control the on / off state of the first medium-low pressure compression section and the interstage structure. The second valve structure is disposed on the intake passage structure connecting the second medium-low pressure compression section and the interstage structure, and the second valve structure is used to control the on / off state of the second medium-low pressure compression section and the interstage structure.
6. The grid-connected device for interstage load of a multi-stage centrifugal compressor according to claim 1, characterized in that, The device also includes a third valve structure and a fourth valve structure; The third valve structure is disposed on the outlet channel structure connecting the first high-pressure compression section and the interstage structure, and the third valve structure is used to control the flow rate of the first high-pressure compression section and the interstage structure; The fourth valve structure is installed on the outlet channel structure connecting the second high-pressure compression section and the interstage structure, and the fourth valve structure is used to control the flow rate of the second high-pressure compression section and the interstage structure.
7. The grid-connected device for interstage load of a multi-stage centrifugal compressor according to claim 1, characterized in that, The interstage structure is a dry structure.
8. The grid-connected device for interstage load of a multi-stage centrifugal compressor according to claim 7, characterized in that, The drying structure includes at least one molecular sieve dehydration tower.
9. The grid-connected device for interstage load of a multi-stage centrifugal compressor according to claim 1, characterized in that, The interstage structure is provided with a detection structure, which is used to detect the pressure and temperature within the interstage structure.
10. A method for grid-connected control of interstage load in a multi-stage centrifugal compressor, characterized in that, The method employs a multi-stage centrifugal compressor interstage load grid connection device as described in any one of claims 1-9, characterized in that the method comprises: Control the operation of the first unit and / or the second unit; The first medium-low pressure compression section and / or the second medium-low pressure compression section are connected to the interstage structure through the intake channel structure, and the exhaust gas in the first medium-low pressure compression section and / or the second medium-low pressure compression section enters the interstage structure through the intake channel. The first high-pressure compression section and / or the second high-pressure compression section are connected to the interstage structure through the exhaust channel structure, and the gas in the interstage structure enters the first high-pressure compression section and / or the second high-pressure compression section through the exhaust channel structure.