Multi-compressor unit coordinated gas injection system for CAES

Abstract

This utility model discloses a multi-compressor unit coordinated gas injection system for CAES, including multiple compressor units, multiple gas storage tanks, and connecting pipelines. The compressor units are divided into fixed unit rows and flexible unit rows. Each fixed unit row is fixedly connected to a corresponding gas storage tank, while the flexible unit rows are selectively connected to each gas storage tank via a diversion valve group and symmetrically arranged pipelines. A mixing chamber is installed at the inlet of each gas storage tank, where the outputs of the fixed and flexible unit rows converge. A check valve is installed on the outlet pipeline of each unit before entering the mixing chamber. The gas storage tanks are connected via pressure balancing pipelines equipped with pressure balancing valves. This system, through an asymmetric parallel topology combining fixed and flexible configurations, a symmetrical pipeline design, and a mixing chamber and pressure balancing structure, solves the problems of multi-unit coupling interference, uneven flow distribution, and pressure instability; it combines operational stability and adjustment flexibility, making it suitable for large-scale compressed air energy storage power stations.

Description

Technical Field

[0001] This utility model belongs to the field of energy and resource development, and in particular to a coordinated gas injection system for multiple compressor units in CAES. Background Technology

[0002] Compressed air energy storage technology, as a crucial technology for large-scale grid energy storage, is seeing its system capacity expand to the megawatt and even gigawatt levels. Against this backdrop, the compression system, as the core subsystem of an energy storage power station, requires multiple compressor units operating in parallel to meet high-power gas injection demands. Simultaneously, the gas storage side typically employs multiple gas storage facilities (such as salt caverns or abandoned mine shafts) to provide sufficient storage capacity. Therefore, achieving coordinated and efficient gas injection from multiple compressor units to multiple gas storage facilities can improve the performance of large-scale compressed air energy storage systems.

[0003] For scenarios involving multiple compressor units injecting gas into multiple gas storage facilities, existing technologies include: simple parallel connection, where all unit outlets converge into a main pipeline before being distributed to each gas storage facility; one-to-one fixed connection, where each compressor unit is fixedly connected to one gas storage facility; and fully flexible connection, using a complex valve matrix to allow any compressor unit to inject gas into any gas storage facility. In terms of pipeline design, existing technologies often adopt a proximity-based layout, lacking consideration for pipeline symmetry and flow resistance balance. A solution relies on compressors with return bypasses and anti-surge control strategies to adapt to pressure changes in the gas storage facilities.

[0004] However, existing technologies still suffer from problems such as coupling interference between compressor units, reduced gas injection efficiency due to uneven pressure in the gas storage tank, and issues with flexibility and stability, due to the lack of a reasonable topology design. Therefore, further research and innovation are needed to address these problems in existing technologies. Utility Model Content

[0005] Purpose of the utility model: In view of the above-mentioned problems of the prior art, this application provides a multi-compressor unit coordinated gas injection system for CAES.

[0006] Technical solution: According to one aspect of this application, a multi-compressor unit coordinated gas injection system for CAES includes multiple compressor units, multiple gas storage tanks, and connecting pipelines, specifically:

[0007] Multi-row compressor units include at least one row of stationary compressor units and one row of flexible compressor units;

[0008] The outlet pipeline of each fixed unit is fixedly connected to the inlet of a corresponding gas storage facility;

[0009] The outlet pipeline of the flexible unit train is connected to the diversion valve group. The multiple outlets of the diversion valve group are connected to the inlet of each gas storage tank through symmetrically arranged connecting pipelines. The symmetrically arranged connecting pipelines make the pipeline resistance from the flexible unit train to each gas storage tank equal.

[0010] Each gas storage unit is equipped with a mixing box at its inlet, where the outlet pipelines of the fixed unit line and the connecting pipelines of the flexible unit line of the corresponding gas storage unit converge.

[0011] Each compressor unit's outlet pipeline is equipped with a check valve before entering the mixing chamber.

[0012] According to another aspect of this application, a multi-compressor unit coordinated gas injection system for CAES further includes:

[0013] The flexible unit is configured as a single row. The diversion valve group includes multiple diversion valves corresponding to the number of gas storage tanks. The inlet of each diversion valve is connected to the outlet pipeline of the flexible unit, and the outlet is connected to the mixing box of the corresponding gas storage tank through an independent connecting pipeline.

[0014] The connecting pipelines from the flexible unit to each gas storage facility have the same diameter and length.

[0015] According to another aspect of this application, the multi-compressor unit coordinated gas injection system for CAES further includes:

[0016] The number of fixed unit rows can be one or more. When multiple fixed unit rows correspond to the same gas storage facility, the outlet pipelines of these multiple fixed unit rows are connected in parallel to the mixing box of the gas storage facility.

[0017] According to another aspect of this application, the multi-compressor unit coordinated gas injection system for CAES further includes:

[0018] The mixing chamber is located upstream of the gas storage inlet, and a flow guiding structure is installed inside the mixing chamber;

[0019] The check valve is installed directly at the interface where the outlet pipeline of each compressor unit enters the mixing box;

[0020] Each check valve has an independent flow detection device installed on its upstream pipeline.

[0021] According to another aspect of this application, the multi-compressor unit coordinated gas injection system for CAES further includes:

[0022] The flow detection device is a vortex flow meter or a Coriolis flow meter, and it is installed 0.5-2 meters upstream of the backflow preventer.

[0023] Each gas storage facility is equipped with a pressure detection device on its inlet header, located in the pipeline section downstream of the mixing box and upstream of the gas storage facility inlet.

[0024] According to another aspect of this application, the multi-compressor unit coordinated gas injection system for CAES further includes:

[0025] Adjacent gas storage facilities are connected by a pressure balancing pipeline, with both ends of the pressure balancing pipeline connected to the inlet main pipe of the adjacent gas storage facility.

[0026] A pressure balancing valve is installed on the pressure balancing pipeline. The pressure balancing valve is either an electric regulating valve or a pneumatic regulating valve.

[0027] According to another aspect of this application, the multi-compressor unit coordinated gas injection system for CAES further includes:

[0028] Each compressor unit consists of 3 or 4 compressor units connected in series, with adjacent compressor units connected by an interstage cooler.

[0029] Each compressor unit is equipped with a variable frequency drive and an inlet guide vane adjustment device at the end of the compressor unit.

[0030] According to another aspect of this application, the multi-compressor unit coordinated gas injection system for CAES further includes:

[0031] Each compressor unit is equipped with an anti-surge valve on its outlet pipe, and the outlet of the anti-surge valve is connected to the inlet pipe of that compressor unit through a return pipe.

[0032] Each compressor unit is also connected in parallel with a bypass pipeline, and a bypass valve is installed on the bypass pipeline.

[0033] According to another aspect of this application, the multi-compressor unit coordinated gas injection system for CAES further includes:

[0034] The variable frequency drive unit of the final compressor unit includes a frequency converter and a variable frequency motor;

[0035] The imported guide vane adjustment device includes an adjustable guide vane mechanism and a guide vane actuator. The adjustable guide vane mechanism is located at the air inlet of the final compressor unit.

[0036] According to another aspect of this application, the multi-compressor unit coordinated gas injection system for CAES further includes:

[0037] The system also includes a control valve assembly, which includes:

[0038] Isolation valves installed on the outlet pipeline of each fixed unit;

[0039] A main isolation valve is installed between the flexible unit row and the diversion valve group;

[0040] Gas storage isolation valves installed on the inlet header of each gas storage facility;

[0041] Among them, the isolation valve, the main isolation valve, and the gas storage isolation valve are all electric ball valves or electric butterfly valves.

[0042] Beneficial effects: This invention solves the problem of multi-unit coupling interference through an asymmetric parallel topology combining fixed and flexible connections; it achieves uniform flow distribution through symmetrical piping design; and it realizes pressure stability through a mixing box and pressure balancing structure. The system combines operational stability and adjustment flexibility, making it suitable for large-scale compressed air energy storage power stations. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the topology of a multi-compressor unit coordinated gas injection system for CAES provided in an embodiment of this application.

[0044] Figure 2 This is a schematic diagram of another topology of a multi-compressor unit coordinated gas injection system for CAES provided in an embodiment of this application.

[0045] Figure 3 A schematic diagram of the internal structure of a compressor unit provided in an embodiment of this application (taking a single column as an example).

[0046] Figure 4 This is a structural diagram of the internal structure of the mixing chamber provided in an embodiment of this application. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings. In the following description, the same or similar parts in the drawings are referred to by the same reference numerals, and repeated descriptions of the same or similar parts are omitted.

[0048] To address the aforementioned issues, the applicant conducted in-depth searches and analyses, and discovered:

[0049] First, existing technologies suffer from coupling interference between compressor units. When multiple units are connected in parallel via a common header, flow fluctuations in any unit can be transmitted through pressure waves, affecting other units and potentially causing surge. Second, uneven pressure in gas storage facilities leads to reduced injection efficiency. Due to differences in geological conditions and injection history, different gas storage facilities experience inconsistent pressure rise rates, resulting in decreased efficiency or even inability to inject gas into high-pressure storage facilities. Third, there is a conflict between flexibility and stability. While fully flexible connections offer flexibility, they are complex to control and have poor stability. Fixed connections, while stable, cannot optimize flow allocation based on storage facility conditions, leading to some units being idle while others are overloaded. Existing technologies, lacking a reasonable topology design, cannot achieve flexible allocation of injection flow while ensuring system stability.

[0050] To solve these problems, combined with Figures 1 to 4 The present invention will be specifically described through the following embodiments.

[0051] Example 1 provides a basic configuration scheme for a multi-compressor unit coordinated gas injection system for CAES, addressing the mismatch between the compressor-side output power, turbine power generation, and gas storage container capacity in large-scale compressed air energy storage systems, as well as the coupling interference problem during parallel operation of multiple compressor units. Specifically, this system achieves coordinated gas injection from multiple compressor units to multiple gas storage tanks through an asymmetric parallel topology. The multi-compressor unit coordinated gas injection system for CAES in this example includes a compressor unit system 100, a gas storage system 200, and a connecting pipeline system 300. The compressor unit system 100 includes multiple rows of compressor units, specifically fixed unit rows 110 and flexible unit rows 120. The fixed unit rows 110 include a first fixed unit row 111 and a second fixed unit row 112, respectively connected to the first gas storage tank 210 and the second gas storage tank 220 in the gas storage system 200. The flexible unit row 120 is configured with only one row; this single-row configuration avoids mutual interference between multiple flexible units and simplifies the system control logic.

[0052] Regarding the connections, the outlet of the first fixed unit row 111 is permanently connected to the inlet of the first gas storage tank 210 via the first main pipeline 311. This connection is permanent and does not change during normal operation. Similarly, the outlet of the second fixed unit row 112 is permanently connected to the inlet of the second gas storage tank 220 via the second main pipeline 312. The outlet of the flexible unit row 120 is connected to a diversion valve assembly 130, which includes a first diversion valve 131 and a second diversion valve 132. The outlet of the first diversion valve 131 is connected to the inlet area of ​​the first gas storage tank 210 via a first flexible connection pipeline 321, and the outlet of the second diversion valve 132 is connected to the inlet area of ​​the second gas storage tank 220 via a second flexible connection pipeline 322.

[0053] Furthermore, this application adopts a symmetrical arrangement design for flexible connection pipelines. The first flexible connection pipeline 321 and the second flexible connection pipeline 322 are arranged symmetrically, specifically in that the two pipelines have the same pipe length (error not exceeding ±2%), the same pipe inner diameter, the same number of bends, and the same elevation change (within ±0.5m). This symmetrical design ensures that the flow resistance of the pipelines from the flexible unit line 120 to each gas storage tank is basically equal, the resistance difference is controlled, and the uniformity of flow distribution is guaranteed.

[0054] At the inlet of each gas storage unit, this system is equipped with a mixing chamber device. The first mixing chamber 410 is located upstream of the inlet of the first gas storage unit 210, 2-3 meters away from the inlet flange. The outlet pipeline of the first fixed unit group 111 and the pipeline of the flexible unit group 120 converge in the first mixing chamber 410 via the first diverter valve 131. The internal volume of the mixing chamber 410 is designed to be 15-25 cubic meters, with a length-to-diameter ratio of 2:1 to 3:1. It is equipped with a baffle structure inside to ensure that compressed air from different sources can be fully mixed, avoiding pressure pulsations caused by uneven flow rates.

[0055] In this application, a first check valve 511 is installed before the outlet pipeline of the first fixed unit train 111 enters the first mixing chamber 410; in other words, a check valve is directly installed before the interface where the outlet pipelines of multiple fixed unit trains converge into the mixing chamber. A second check valve 512 is installed before the first flexible connection pipeline 321 of the flexible unit train 120 enters the first mixing chamber 410. The check valve adopts an axial flow structure, with an opening pressure difference of less than 0.02 MPa, which can prevent the backflow of high-pressure gas from other operating units when a compressor train stops or malfunctions. The installation position of the check valve is 0.5-1 meter away from the inlet flange of the mixing chamber. This distance ensures the implementation of the backflow prevention function and facilitates maintenance and repair.

[0056] In other words, the number of fixed compressor units in a multi-row compressor unit is at least one, and the outlet pipeline of each fixed compressor unit is fixedly connected to the inlet of a corresponding gas storage tank. Each fixed compressor unit is equipped with a check valve before entering the mixing box. However, there is only one flexible compressor unit, whose outlet pipeline is connected to a diverter valve group. The diverter valve is further connected to the inlet of each gas storage tank by multiple symmetrically arranged outlet connecting pipelines. The mixing box is located at the inlet of each gas storage tank and receives the outlet pipelines of the corresponding fixed compressor unit and the connecting pipelines of the flexible compressor unit in the box.

[0057] The system in this embodiment demonstrates excellent performance in actual operation. When the system needs to inject gas into the first gas storage tank 210, the first stationary unit 111 continues to operate, providing a basic injection flow rate of 60-80 Nm³. 3 / s; When it is necessary to increase the gas injection volume, open the first diversion valve 131, and the output flow of the flexible unit line 120 is 30-40 Nm 3 The gas flow is supplemented into the first mixing chamber 410 via the first flexible connection pipeline 321. After the two gas flows are fully mixed in the mixing chamber, they enter the first gas storage tank 210 with stable pressure and flow rate. This fixed and flexible configuration allows the system to ensure a stable supply of base load while flexibly adjusting the total gas injection volume according to energy storage needs, thus expanding the adjustment range.

[0058] Example 2 describes the specific structural configuration of the flexible unit group 120, and elaborates on the design features of the diversion valve group 130 and the implementation method of symmetrical pipeline arrangement.

[0059] This embodiment of the flexible compressor unit adopts a single-row configuration. Specifically, the flexible compressor unit 120 includes four compressor units connected in series: a first compressor 121, a second compressor 122, a third compressor 123, and a fourth compressor 124. The compressor units are connected via interstage piping, and the compression ratio distribution follows the principle of equal enthalpy rise, with the single-stage pressure ratio controlled within the range of 1.5-8. The total output pressure range of the flexible compressor unit 120 is 0.4-10 MPa, and the rated flow rate is 40 Nm³. 3 / s, with an installed capacity of 180MW.

[0060] The diversion valve assembly 130 is a component that enables flexible selective gas injection from the unit to multiple gas storage tanks. The diversion valve assembly 130 includes an inlet header 133, a first diversion valve 131, a second diversion valve 132, and corresponding connecting pipes. The inlet header 133 is a seamless steel pipe with a DN600 diameter, a wall thickness of 20mm, and a design pressure of 12MPa. Both the first diversion valve 131 and the second diversion valve 132 are electric ball valves with a nominal diameter of DN400. The valve body is made of forged steel, and the valve ball is designed for full bore, with a flow resistance coefficient of less than 0.15. The centerlines of the two diversion valves are equidistant from the centerline of the inlet header, both being 1.5 meters, forming a symmetrical T-shaped branch structure.

[0061] The control logic design of the diversion valves takes into account the need to prevent pressure surges. Furthermore, each diversion valve is equipped with an independent electric actuator, with an opening time set to 30-60 seconds and a closing time set to 60-90 seconds. The actuator has a manual emergency operation function, which can be operated via handwheel in the event of a power outage. The diversion valves are also equipped with a valve position feedback device to monitor the valve opening in real time with an accuracy of ±1%.

[0062] Based on this, the symmetrical piping arrangement can be implemented as follows: the first flexible connection pipe 321 and the second flexible connection pipe 322 start from the diversion valve group 130 and are arranged in a mirror-symmetrical manner. Specific parameters are as follows: both pipes are DN400×16mm seamless steel pipes, with a total length of 85±1 meters for a single pipe, including three 90-degree elbows (bending radius 1.5D) and two 45-degree elbows (bending radius 2D). Pipe supports are spring hangers, spaced no more than 6 meters apart, allowing axial displacement of ±50mm to accommodate thermal expansion and contraction. The horizontal sections of the two pipes have the same elevation (±100mm), and the vertical sections have the same height (12±0.2 meters).

[0063] Furthermore, in this embodiment, a first flow detection device 611 is provided on the first flexible connection pipe 321, and a second flow detection device 612 is provided on the second flexible connection pipe 322. The flow detection device adopts a Coriolis flow meter with a measurement accuracy of ±0.5% and a range of 0-60 Nm. 3 / s. The flow meter is installed in a straight pipe section 10D downstream and 5D upstream of the diversion valve to allow for full flow field development; in other words, the flow detection device can be installed 0.5-2 meters upstream of the check valve. Actual operating data shows that when both diversion valves are fully open simultaneously, the flow deviation between the two pipelines does not exceed 2%, verifying the feasibility of the symmetrical design.

[0064] In other words, the diversion valve group is connected to the outlet pipeline of the flexible unit column at the upper end and symmetrically connected to the mixing box of the corresponding gas storage tank at the lower end; its number corresponds to the number of gas storage tanks, and the symmetrically arranged connecting pipelines have the same pipe diameter and pipe length.

[0065] It should be understood that the flexible unit array in this embodiment can achieve four operating modes: injecting gas into the first gas storage tank alone, with the first diversion valve 131 fully open and the second diversion valve 132 closed; injecting gas into the second gas storage tank alone, with the first diversion valve 131 closed and the second diversion valve 132 fully open; simultaneously injecting gas into both gas storage tanks equally, with both diversion valves fully open; and injecting gas into the two gas storage tanks proportionally, adjusting the opening of the two diversion valves to achieve flow distribution, with the distribution ratio adjustable between 3:7 and 7:3. This flexible operating mode allows the system to adapt to different pressure states and energy storage requirements of the gas storage tanks.

[0066] Example 3 provides a specific process for configuring fixed unit rows, especially when a single gas storage facility needs to be configured with multiple rows of fixed units. For large-capacity gas storage facilities (volume exceeding 50,000 cubic meters) or long-term energy storage needs (energy storage duration exceeding 8 hours), a single row of fixed units cannot meet the gas injection flow requirements, and multiple rows of fixed units need to be configured for parallel operation.

[0067] Taking the first gas storage facility 210 as an example, when the design volume of the gas storage facility is 80,000 cubic meters, the energy storage time is 10 hours, and the rated power of a single-row compressor unit is 50MW, calculations show that two rows of stationary units are required. The first stationary unit row 111 includes a first sub-unit row 111a and a second sub-unit row 111b, and the two rows of units are connected in parallel. Each sub-unit row contains four compressors connected in series, and the structural parameters are similar to those of the flexible unit row. In other words, when the number of stationary unit rows corresponding to the same gas storage facility is greater than one, the outlet pipelines of multiple stationary unit rows are connected in parallel to the mixing chamber of the gas storage facility.

[0068] The outlet of the first sub-unit 111a is connected to the first manifold 315 via the first sub-pipe 311a, and the outlet of the second sub-unit 111b is also connected to the first manifold 315 via the second sub-pipe 311b. The first sub-pipe 311a and the second sub-pipe 311b are DN400 in size and are connected at the junction using a Y-tee. The two branch pipes of the tee are at a 45-degree angle to the main pipe; this design minimizes flow loss. The first manifold 315 is DN600 in size, 8 meters long, and its end is connected to the first mixing chamber 410 via a diffuser (DN600 / DN800).

[0069] To ensure stable operation of the parallel units, this embodiment installs an independent flow regulation system at the outlet of each sub-unit line. The outlet of the first sub-unit line 111a is equipped with a first regulating valve 711a and a first flow meter 811a, while the outlet of the second sub-unit line 111b is equipped with a second regulating valve 711b and a second flow meter 811b. The regulating valves are cage-type regulating valves with an adjustable ratio of 50:1 and an equal percentage flow characteristic. During normal operation, by adjusting the opening of the two regulating valves, the output flow deviation between the two lines of units is controlled within ±3%.

[0070] In other embodiments, stationary unit line 1 and stationary unit line 2 are connected in parallel and ultimately connected to gas storage tank 1 via mixing box 1. Stationary unit line 1 is connected to a common manifold via connecting pipe 311, and stationary unit line 2 is connected to a common manifold via connecting pipe 312. Two flow detection devices, 811 and 812, are also installed on their connecting pipes respectively. The flow then passes through check valve 511 and connects to mixing box 1.

[0071] In this embodiment, pressure balance of the parallel units is achieved through the following measures: pressure transmitters are installed at the outlets of the last compressors of the two sub-units, with a measurement accuracy of ±0.25%FS and a sampling frequency of 100Hz. Next, a buffer tank 316 with a volume of 5 cubic meters and an internal pressure pulsation attenuation rate greater than 80% is installed on the first busbar 315. The buffer tank 316 has a porous distribution plate inside to evenly disperse the inlet airflow, reducing eddies and pressure unevenness.

[0072] Furthermore, the minimum number of fixed unit rows is one row, enabling the system to have basic gas injection capability; the maximum number of rows is N. _max =V×P _rated / (Q _unit ×T×3600); where V is the gas storage volume (cubic meters), P _rated Q is the rated pressure (MPa) of the gas storage facility. _unit Rated flow rate of a single-unit generator (Nm³) 3 / s), T is the designed energy storage duration (hours). For this embodiment, N _max=80000×10 / (0.67×10×3600)≈3.3, rounded to 3 columns, but considering economy and control complexity, 2 columns are actually configured.

[0073] When two stationary generating units are running in parallel, start the first sub-unit, 111a. After it stabilizes (approximately 5 minutes), start the second sub-unit, 111b. During startup, the regulating valve 711b of the second sub-unit remains at 30% opening, gradually increasing its opening as the unit load rises until it balances the flow rate with the first sub-unit. The shutdown sequence is the reverse: gradually close the regulating valve of the unit that was started first, transferring the load to the unit that was started first, and then shut down.

[0074] The configuration method of this embodiment has been verified in a 300MW compressed air energy storage demonstration project. Actual measurement data shows that the total flow stability of the two parallel stationary units is better than ±2%, and the pressure fluctuation is less than ±1%. In the event of a failure in one unit, the other unit can take over 70% of the load within 2 minutes, ensuring uninterrupted energy storage.

[0075] Example 4 provides a specific configuration of the mixing chamber and detection system to achieve coordinated gas injection from multiple units and stable system operation. This includes, in particular, the internal structure of the first mixing chamber 410, the installation method of the check valve, and the complete layout of the detection system.

[0076] Accordingly, the first mixing chamber 410 adopts a horizontal cylindrical structure with an inner diameter of 2.5 meters, a length of 6 meters, a design pressure of 12 MPa, and a working pressure of 0.4-10 MPa. The chamber is made of 16MnR steel plate with a wall thickness of 32 mm, and the inner surface is polished with a roughness Ra≤3.2μm. The two ends of the mixing chamber 410 use standard elliptical heads, each equipped with a manhole (DN600) and various connecting pipes. The chamber is installed horizontally and supported on a concrete foundation by four saddle-type supports, which allow axial sliding to accommodate thermal expansion.

[0077] Furthermore, the flow guiding structure inside the mixing chamber 410 is used to achieve thorough mixing. A flow guide plate assembly 415a is installed 1 meter from the outlet end, adopting an inclined blade structure with 12 flow guide blades arranged in a spiral shape at a spiral angle of 30 degrees, causing the airflow to rotate and enhancing the mixing effect.

[0078] In some embodiments, the first check valve 511 is installed on the outlet pipe of the first fixed unit column 111, or in other words, each check valve is correspondingly installed on the outlet pipe of each compressor, before the interface leading into the mixing box; 800mm away from the inlet flange of the mixing box 410. The check valve 511 adopts an axial flow lifting structure, with a valve disc diameter of 380mm and a stroke of 60mm, and is equipped with a buffer spring to reduce closing impact. The valve body and the pipeline are butt-welded, and the weld is subjected to 100% radiographic testing. The installation direction of the check valve 511 strictly follows the flow direction marking, and the angle between the valve disc lifting axis and the horizontal plane does not exceed 15 degrees, so as to achieve gravity-assisted closure. Pressure measuring points are set before and after the check valve to monitor the valve pressure drop, which does not exceed 0.05MPa during normal operation.

[0079] In some possible scenarios, the flow detection system is configured as follows: a first flow detection device 811 is installed 1.5 meters upstream of the first check valve 511, using an insertion vortex flow meter with a measurement range of 0-100 Nm. 3 / s, accuracy class 0.5. The sensor probe of the flow meter is inserted to a depth of 1 / 3 of the pipe diameter. The flow meter is equipped with temperature and pressure compensation functions. The temperature sensor uses a PT100 platinum resistance thermometer, and the pressure sensor has a range of 0-12MPa. The signal processing unit has 4-20mA current output and HART communication function, which can be remotely debugged and calibrated.

[0080] Upstream of the second check valve 512 (flexible unit pipeline), a second flow detection device 812 is also configured, with the same technical parameters as the first flow detection device. Data from both flow detection devices is transmitted to the control system in real time for calculating the total injection flow rate and distribution ratio. When abnormal flow fluctuations (change rate exceeding 10% / min) are detected, the system automatically alarms and takes protective measures.

[0081] For example, the pressure detection system is located downstream of the mixing tank. The main pressure detection device 910 is installed on the inlet header of the first gas storage tank 210, 3 meters from the outlet of the mixing tank. It employs an intelligent differential pressure transmitter with a range of 0-16 MPa, an accuracy of ±0.075%, and a response time of less than 100 ms. The transmitter features a dual-diaphragm design, allowing continued operation even if one diaphragm fails. Furthermore, two backup pressure detection points 911 and 912 are provided, using pressure sensors based on different principles (strain gauge and piezoresistive), forming a redundancy configuration of two out of three.

[0082] The mixing chamber 410 is also equipped with a comprehensive safety monitoring system. A safety valve interface is located at the top of the chamber, housing two parallel spring-loaded safety valves with a release pressure of 10.5 MPa and a discharge capacity of 1.2 times the maximum flow rate. A drain port and steam trap are located at the bottom of the chamber to periodically discharge condensate and impurities. A temperature measuring point is located in the middle of the chamber to monitor the temperature of the mixed gas, within a normal range of 40-80℃. When the temperature exceeds 85℃, the water spray cooling system is activated.

[0083] The mixing chamber system in this embodiment performs excellently in actual operation. Measured data shows that after passing through the mixing chamber, the pressure pulsation amplitude decreases, the temperature difference between airflows from different sources decreases, and the non-uniformity of flow velocity distribution is improved, verifying the feasibility of the mixing chamber design.

[0084] Example 5 describes the structural configuration of a pressure balancing system between gas storage facilities, used to solve the problem of inconsistent pressure among multiple gas storage facilities and avoid airflow crosstalk. The pressure balancing system achieves dynamic pressure equalization by establishing controllable connection paths between the gas storage facilities.

[0085] In one example, pressure balancing pipeline 330 connects the inlet headers of the first gas storage unit 210 and the second gas storage unit 220. The specific connection location is chosen on a straight pipe section 5-8 meters away from the inlet flange of each gas storage unit, avoiding the influence zone of elbows and reducers. Pressure balancing pipeline 330 uses DN300 seamless steel pipe with a wall thickness of 14mm, and a total length of approximately 25 meters, including two 90-degree elbows and one horizontal straight pipe section. The center elevation of the pipeline is consistent with the inlet header of the gas storage unit to avoid the formation of liquid pockets.

[0086] The pressure balancing valve 350 is installed in the middle of the pressure balancing pipeline 330. It adopts an electric V-type ball valve structure, with a nominal diameter of DN300 and a design pressure of 12MPa. The V-type ball valve is characterized by its near-equal percentage flow characteristic, offering high flow regulation accuracy at small openings, making it particularly suitable for pressure balancing control. The valve actuator is an intelligent electric actuator with an output torque of 3000 N·m, a full stroke time of 45 seconds, and a power-off position holding function. The actuator's built-in control module can receive 4-20mA control signals, achieving continuous regulation from 0-100%.

[0087] In another embodiment, the first gas storage tank 210 and the second gas storage tank 220 are directly connected through a pressure balancing pipeline 330, and the pressure balancing valve 350 is located in the middle of the pressure balancing pipeline 330.

[0088] Furthermore, based on the differential pressure control principle, a pressure balancing system is set up. Accordingly, a first pressure sensor 921 is installed on the inlet header of the first gas storage tank 210, and a second pressure sensor 922 is installed on the inlet header of the second gas storage tank 220. The signals from both sensors are sent to the differential pressure controller. When the differential pressure ΔP = |P1 - P2| > 0.1 MPa, the pressure balancing valve 350 starts to operate. If P1 > P2, the valve opening is calculated according to the formula θ = K1 × ΔP + K2 × dΔP / dt, where K1 = 100% / MPa and K2 = 50% / (MPa / mins), to ensure smooth adjustment.

[0089] The pressure balancing line 330 is also equipped with flow and direction detection devices. The bidirectional flow meter 360 is installed 2 meters upstream of the pressure balancing valve 350, employing the ultrasonic time-of-flight measurement principle to measure flow in both directions, with a range of -50 to +50 Nm. 3 / s. The flow direction indicator 361 uses a mechanical flap structure to visually display the airflow direction. When an abnormally high flow rate (exceeding 30 Nm) is detected... 3 When the gas storage tank leaks, the system automatically shuts off the pressure balancing valve and issues an alarm when the gas storage tank leaks (e.g., when the gas storage tank leaks).

[0090] To ensure system safety, the pressure balancing pipeline is equipped with multiple protection measures. Manual isolation valves 351 and 352 are installed on both sides of the pressure balancing valve 350 for maintenance and emergency isolation. These isolation valves are forged steel gate valves with a zero-leakage sealing standard. An air vent valve 353 is installed at the highest point of the pipeline, and a drain valve 354 is installed at the lowest point. The pipeline also includes a rupture disc device 355 with a burst pressure of 11 MPa, serving as a final safety barrier.

[0091] In this application, the operating modes of the pressure balancing system include: pressure equalization mode: when two gas storage tanks are injecting gas but the loads are different, pressure balancing is achieved through the pressure balancing valve, with the valve opening generally between 20-50%; complementary mode: when one gas storage tank is injecting gas and the other is stationary, pressure equalization can be achieved slowly through a small opening (5-15%); isolation mode: when it is necessary to control the pressure of each gas storage tank individually, the pressure balancing valve is closed; emergency pressure relief mode: when the pressure of a certain gas storage tank rises abnormally, the pressure balancing valve can be fully opened to quickly relieve pressure.

[0092] In this embodiment, actual operating data shows that after activating the pressure balancing system, the pressure difference between the two gas storage tanks can be controlled within 0.05 MPa, improving the coordination of pressure fluctuations. When the compressor unit of one gas storage tank fails and shuts down, the pressure balancing system can disperse the pressure surge to the other gas storage tank within 30 seconds, avoiding the impact of sudden pressure changes on the operating unit. Furthermore, at the end of the energy storage period, when the gas storage tank pressure approaches its upper limit, the system can extend the gas injection time through pressure balancing control, thereby improving the utilization rate of the energy storage capacity.

[0093] Example 6 describes the internal series configuration of the compressor unit, including the connection method of multiple compressor stages, the interstage cooling system, the anti-surge protection system, and other components. Taking the first fixed unit column 111 as an example, the specific implementation of the four-stage compressor series system is explained.

[0094] The first stationary compressor unit, column 111, comprises four centrifugal compressors connected in series: compressor C1, compressor C2, compressor C3, and compressor C4. Each compressor is connected via interstage piping and equipment to form a complete compression system. The inlet of compressor C1 is connected to an atmospheric intake pipe and is equipped with an intake filter and silencer, with a filtration accuracy of 5 μm and a noise reduction of 35 dB(A). The outlet of compressor C4 is a high-pressure output pipe, connected to the subsequent mixing chamber system.

[0095] The pressure ratio distribution of each compressor stage is determined based on the principle of optimal isentropic efficiency. The first compressor stage (C1) has a pressure ratio of 7.34, the second compressor stage (C2) has a pressure ratio of 5.26, the third compressor stage (C3) has a pressure ratio of 2.03, and the fourth compressor stage (C4) has a pressure ratio of 1.3, with a total pressure ratio of approximately 101, capable of compressing atmospheric air to 10 MPa. The decreasing pressure ratio design takes into account the impact of temperature rise on compressor performance, ensuring that each compressor stage operates within its high-efficiency range.

[0096] In some embodiments, an interstage cooling system is employed to ensure efficient operation of the compressor unit. Specifically, the first interstage cooler IC1 is located between the first-stage compressor C1 and the second-stage compressor C2, employing a shell-and-tube heat exchanger with a heat exchange area of ​​450 square meters. Cooling water flows through the shell side, and compressed air flows through the tube side. The cooling water inlet temperature is 28°C, the outlet temperature is 35°C, and the flow rate is 850 cubic meters per hour. The compressed air is cooled from 125°C to 45°C with a pressure drop of less than 0.015 MPa. The second-stage interstage cooler IC2 and the third-stage interstage cooler IC3 are configured similarly, with heat exchange areas of 420 square meters and 380 square meters respectively, ensuring that the inlet temperature of each compressor stage is controlled within the range of 40-50°C.

[0097] This application also includes an anti-surge system to ensure safe operation of the unit. Accordingly, each compressor stage is equipped with an independent anti-surge circuit. Taking the first compressor stage C1 as an example, the anti-surge valve ASV1 is installed on the compressor outlet pipe, and the valve outlet is connected back to the compressor inlet pipe via the return pipe RL1. The anti-surge valve ASV1 is a pneumatic diaphragm regulating valve with a diameter of DN200, a Cv value of 180, and a full stroke time of 3 seconds. A return cooler RC1 is installed on the return pipe RL1 to prevent the return gas temperature from becoming too high. The anti-surge control is based on the compressor's real-time operating point. When the operating point approaches the surge line (margin less than 10%), the anti-surge valve opens rapidly with a response time of less than 1 second.

[0098] In addition to the anti-surge circuit, each compressor section is also equipped with a bypass piping system. The first bypass piping, BP1, connects to the inlet and outlet of compressor C1, with a pipe diameter of DN150, and is equipped with an electric ball valve BV1. The bypass system is mainly used for load regulation during startup, reducing startup power through bypass return flow; supplementing flow during low-load operation to prevent entry into the surge zone; and rapid unloading during emergency shutdown to protect the compressor rotor. The control of the bypass valve is coordinated with the anti-surge valve to form dual protection.

[0099] This embodiment can also employ an optional configuration of three compressors connected in series. In this configuration, the single-stage pressure ratio is increased, reducing the number of devices and floor space; however, the compressor outlet temperature rises, requiring enhanced interstage cooling. The three-stage configuration is suitable for projects with lower gas storage pressures (6-8 MPa) or those sensitive to investment costs.

[0100] Example 7 describes the configuration of the regulating system for the final stage compressor, particularly the coordinated control scheme of the variable frequency drive and the inlet guide vane regulating device. This regulating system is used to achieve efficient variable operating condition operation of the compressor unit.

[0101] The variable frequency drive unit configured in the fourth stage compressor C4 includes a frequency converter VFD1 and a variable frequency motor M4. The frequency converter VFD1 is a high-voltage frequency converter with a rated capacity of 13MVA, an input voltage of 10kV, and an output frequency that is continuously adjustable from 0-60Hz. The frequency converter adopts a multi-level topology with power units connected in series. The 36 power units are divided into three phases, with 12 units connected in series per phase. The output voltage waveform is close to a sine wave, and the harmonic content (THD) is <2%. The frequency converter efficiency exceeds 96% at 50% load and reaches 97.5% at full load.

[0102] In other words, the multi-stage compressor units are connected in series via interstage coolers to form a series compressor unit, and the last compressor unit is also equipped with a variable frequency drive and an inlet guide vane adjustment device.

[0103] The VFD1 frequency converter's cooling system uses water cooling with a flow rate of 45 cubic meters per hour and an inlet water temperature not exceeding 33℃. The converter room is equipped with an independent constant temperature and humidity air conditioning system, maintaining an ambient temperature of 20-25℃ and a relative humidity of 40-60%. The frequency converter is equipped with input and output filters to limit dv / dt to < 500V / μs, protecting the motor insulation. The control system uses a vector control algorithm, enabling constant torque and constant power control with a speed control accuracy of ±0.1%.

[0104] The M4 variable frequency motor is a specially designed high-voltage asynchronous motor with a rated power of 12MW, a rated voltage of 10kV, and a rated speed of 2980rpm. The motor features enhanced insulation to withstand the high-frequency pulses from the inverter. The rotor uses a copper bar structure to reduce rotor resistance and improve efficiency. The motor is equipped with PT100 temperature sensors to monitor the temperature of the stator windings (6 points), bearings (4 points), and cooling air (2 points). The bearings are sliding bearings equipped with vibration sensors, and vibration limits comply with ISO10816-3 standards.

[0105] The imported guide vane adjustment device IGV4 is installed in the intake chamber of the fourth-stage compressor C4. The guide vane mechanism consists of 16 adjustable guide vanes with a blade chord length of 180mm and a maximum turning angle range of -15° to +85°. The guide vanes are precision cast from 17-4PH stainless steel with a surface roughness of Ra0.8 to ensure aerodynamic performance. Each guide vane is supported by an independent shaft using double-row angular contact ball bearings, with preload ensuring backlash-free transmission. All guide vanes are synchronously linked via a linkage mechanism and driven by a single actuator, ensuring that the blade angle consistency deviation is less than ±0.5°.

[0106] The guide vane actuator EA4 employs an electro-hydraulic servo actuator with an output torque of 1500 N·m, a full stroke time of 8 seconds, and a positioning accuracy of ±0.2°. The actuator features a power-off position-holding function, maintaining its current position even when the control signal is interrupted. The hydraulic system operates at a pressure of 14 MPa, uses fire-resistant oil, and maintains an oil temperature of 40-60°C. The actuator is equipped with an LVDT displacement sensor, providing position feedback with a resolution of 0.01°.

[0107] This embodiment employs a coordinated control strategy of frequency converter and guide vane. Furthermore, the control system adjusts the flow rate Q according to the required flow rate. _req The combination of rotational speed n and guide vane angle α is determined according to the optimization algorithm. When Q _req >85%Q _rated At (rated flow rate), the guide vanes are fully open (α=85°), and the rotational speed n∈[85%,100%] is adjusted by frequency converter; when Q _req When Q ∈ [50%, 85%], the rotational speed is maintained at n=85%, and the guide vane α∈[30°, 85°] is adjusted; when Q _req When the speed is less than 50%, the rotational speed is reduced to n=70%, and the guide vanes are adjusted to α∈[-15°,30°]. This segmented control strategy keeps the compressor efficiency above 82% across the entire operating range.

[0108] The dynamic response characteristics of the control system have been optimized. When the frequency converter uses V / f control mode, the acceleration time is set to 45 seconds and the deceleration time to 60 seconds to avoid current surges. Guide vane adjustment uses PID control with a proportional coefficient Kp = 2.5 and an integral time T... i =15 seconds, differential time T d=3 seconds. When the load changes abruptly, the guide vanes respond quickly (2-3 seconds), followed by gradual adjustment by the frequency converter (20-30 seconds) to achieve rapid stabilization. Actual measurements show that when the load suddenly drops from 100% to 50%, the system reaches a new steady state within 35 seconds, with pressure fluctuations not exceeding ±2%.

[0109] This control system also features adaptive optimization. The controller has a built-in compressor performance MAP chart containing efficiency data for 1200 operating points. The system calculates the current efficiency in real time, compares it with the MAP chart, and automatically fine-tunes the speed and guide vane angle to find the optimal operating point. After three months of operation and optimization, the average efficiency has improved, and annual energy savings have increased.

[0110] Example 8 describes the configuration of the system's control valve assembly, which constitutes the system's operation control and safety isolation system. The control valve assembly is distributed at critical nodes of the system, realizing unit isolation, flow path switching, and emergency protection functions.

[0111] The isolation valve configuration for the fixed unit train is as follows: The first isolation valve IV1 is installed on the main outlet pipe of the first fixed unit train 111, located 3 meters upstream of the check valve 511. The first isolation valve IV1 is an electric ball valve with a nominal diameter of DN500, a design pressure of 12MPa, and a valve body made of forged steel A105N. The ball is a fixed ball design, with independent floating upstream and downstream valve seats. The sealing surface is overlaid with Stellite alloy with a hardness of HRC58-62. The valve's sealing rating meets the zero-leakage requirement of API 598 standard. The electric actuator has a power of 7.5kW and an output torque of 8000N·m. It is equipped with a manual emergency operation mechanism; the handwheel is connected to the electric clutch, allowing for manual operation during power outages.

[0112] The main isolation valve MIV of the flexible unit train is located upstream of the diversion valve group 130, specifically between the outlet of the flexible unit train 120 and the inlet header 133 of the diversion valve group. The main isolation valve MIV is an electric butterfly valve with a nominal diameter of DN600 and a triple eccentric metal seal design. The valve plate is made of duplex stainless steel 2205, and the valve seat is a multi-layer metal sheet stacked structure with a sealing pressure of 15-25 MPa. The butterfly valve has a flow resistance coefficient of less than 0.2 and a pressure loss of less than 0.02 MPa when fully open. The actuator is an intelligent rotary electric actuator with a Profibus-DP communication interface, enabling remote control and status monitoring.

[0113] Regarding the configuration of the isolation valves for the gas storage facility, the following applies: The first gas storage facility isolation valve, TIV1, is installed on the 210 inlet header of the first gas storage facility, 10 meters from the inlet flange. It is an electrically operated wedge gate valve with a nominal diameter of DN800. The valve body is made of cast steel, with an inner cavity coated with a nickel-based alloy to improve corrosion resistance. The gate is a flexible gate structure with an O-ring seal in the center and metal sealing surfaces on both sides, achieving double sealing. The valve stroke is 450mm, the full stroke time is 120 seconds, and it can be stopped at any intermediate position. It is equipped with two limit switches and one potentiometer, providing fully open, fully closed, and continuous position signals.

[0114] In some embodiments, when the compressor unit shuts down in an emergency, the corresponding isolation valve closes after a 30-second delay upon receiving the shutdown signal to prevent sudden pressure changes. When a pipeline leak is detected (pressure drop rate > 0.5 MPa / s), the isolation valves at both ends of the leaking section automatically close. The gas storage isolation valves are interlocked with the gas storage safety system; when the gas storage pressure exceeds 10.2 MPa or the temperature exceeds 100°C, the isolation valves automatically close. The status signals of all isolation valves are sent to the DCS system, and the operator station displays the real-time valve status, including five states: fully open, fully closed, intermediate position, fault, and manual switch.

[0115] In addition to the main isolation valves, the system is also equipped with auxiliary control valve assemblies. Regulating valves are installed on the cooling water lines of each interstage cooler to automatically adjust the cooling water flow rate based on the outlet temperature. A quick-closing valve with a response time of less than 0.5 seconds is installed on the anti-surge circuit. An automatic vent valve is installed at the highest point of the system, automatically opening to release air when the pressure difference reaches 0.02 MPa. An automatic drain valve is installed at the lowest point of the system, employing both timed drain and level-based drain control.

[0116] The power supply and control of the control valve assembly adopt a redundant design. Each electric valve is equipped with dual power supplies: the main power supply comes from a 10kV / 380V power center, and the backup power supply comes from a UPS system, with a switching time of less than 20ms. The control signal adopts dual channels: the main channel is a 4-20mA analog signal, and the backup channel is a 24VDC switching signal. The actuator has a built-in watchdog circuit, which automatically executes the preset fail-safe action after a 3-second signal interruption: the isolation valve remains in its original position, and the regulating valve opening is 50%.

[0117] The control valve assembly configuration in this embodiment has passed SIL2 safety integrity level certification. In a 300MW compressed air energy storage project, this configuration underwent more than 5,000 operating cycles, maintaining excellent valve sealing performance with an internal leakage rate of less than 0.01%Cv. The system interlock protection activated 35 times, all of which executed correctly, preventing equipment damage and operational accidents.

[0118] Example 9 provides a topology design method for multiple compressor units based on capacity matching. This method solves the problem of capacity matching among the compression side, storage side, and turbine side in a large-scale compressed air energy storage system. It explains how to determine the configuration quantity and connection method of the compressor units.

[0119] Furthermore, the basic parameters of the system are determined. Assume the system power is 700MW = 2 * 350MW, and the energy release duration is T. _storage =6 hours, generating 4200MWh of electricity, storing 4200 / 0.6 = 7000MWh of energy. Total gas storage volume V _total =800000 * 2 cubic meters, working pressure range 4-10MPa. System compression time 8 hours, total power required for system compression P _comp_total The rated power P of a single compressor unit is 7000 / 8 = 875MW. _comp =180MW.

[0120] Calculate the required number of compressor units. Number of stationary compressor units (N) _fixed =P _comp_total / P _comp =875 / 180=4.86, rounded up to 5 columns. Considering operational flexibility, 4 fixed units and 1 flexible unit are configured. The number of gas storage facilities is determined to be 2 based on geological conditions, with volumes of V1=80,000 cubic meters and V2=80,000 cubic meters respectively. According to the volume ratio, the first gas storage facility is configured with 2 fixed units, and the second gas storage facility is configured with 2 fixed units.

[0121] The pipeline design must be symmetrical. The pipelines from the flexible unit to the two gas storage tanks must be symmetrical to ensure uniform flow distribution. The pipeline design adopts the principle of mirror symmetry: the pipeline path is symmetrical, the path length from the center point of the diversion valve group to the mixing box of each gas storage tank is equal, and the deviation is controlled within ±1%; the pipe diameter is consistent, all using DN400×16mm; the pipe fittings are the same, each branch includes the same number and type of elbows, tees, and other pipe fittings; the elevation layout is consistent, with the elevation of horizontal and vertical pipe sections remaining the same.

[0122] In terms of layout, the diversion valve assembly is located at the geometric center of the two gas storage tanks, with coordinates X=(X1+X2) / 2 and Y=(Y1+Y2) / 2. Next, the pipeline routing follows a convergence-then-separation principle, first delivering gas from the flexible unit outlet through a DN600 main pipe to the diversion center, and then distributing it symmetrically. Furthermore, in the vertical direction, the two branch lines have the same elevation gain of 12 meters and an elevation angle of 30 degrees. Each branch line is further equipped with three symmetrical support points with identical support stiffness.

[0123] Alternatively, when site conditions do not allow for a symmetrical layout, an asymmetrical piping configuration with flow regulating valves can be used. The specific method is to add a regulating valve to the shorter branch of the piping, thereby increasing the local resistance to balance the total resistance of the two branches. The Cv value of the regulating valve is calculated using the formula: Cv _add =Q×sqrt(ΔP _diff / ΔP _valve ), where ΔP _diff Let ΔP be the resistance difference between the two branches. _valve The allowable pressure drop of the regulating valve is set at 0.05-0.1 MPa. This approach increases system complexity and operating energy consumption, and is only used in special circumstances.

[0124] Furthermore, the pipe resistance is calculated to verify the symmetry. The Darcy-Weisbach formula is used to calculate the straight pipe resistance: ΔP _pipe =f×(L / D)×(ρv 2 / 2), where f is the friction coefficient (taken as 0.015), L is the pipe length, D is the pipe diameter, ρ is the gas density, and v is the flow velocity. Local resistance is calculated using the resistance coefficient method: ΔP _local =K×(ρv 2 / 2), 90-degree elbow K=0.75, tee K=1.2. The calculation results show that the total resistance of each branch is about 0.18MPa, the resistance difference between the two branches is less than 0.005MPa, and the flow deviation is less than 1.5%.

[0125] This design approach also includes scalability considerations. An interface for a third gas storage unit is reserved, and a DN400 flange interface is provided at the diversion valve assembly for future expansion. The piping support and foundation design incorporates a 125% overload capacity to accommodate future increases in operating pressure. The control system includes reserved expansion slots to connect to control signals from two additional compressor units. This design allows for phased construction and gradual capacity expansion.

[0126] According to one aspect of this application, a structural scheme for solving the dual coupling problem is described, serving as technical support for the operation of multiple parallel compressor units.

[0127] Accordingly, the first layer of coupling occurs when flexible units simultaneously inject gas into multiple gas storage facilities. Once all diversion valves are open, all fixed and flexible units form a coupled system through the gas storage facilities. Flow fluctuations in any unit will affect all other units via pressure waves.

[0128] A structural solution could be a buffer design for the mixing chambers. Specifically, each mixing chamber has an internal volume of 23.5 m³. 3This is equivalent to the output of a single compressor unit for 35 seconds, forming a gas buffer zone. The porous distribution plate inside the mixing chamber reduces the incoming high-speed airflow (v=25m / s) to below 5m / s, converting dynamic pressure into static pressure. Actual measurement data shows that the 30Hz pressure pulsation is attenuated after passing through the mixing chamber, isolating high-frequency disturbances.

[0129] It can also serve as a decoupling mechanism for pressure balancing pipelines. Accordingly, pressure balancing pipelines not only balance the pressure in gas storage facilities but also provide a bypass path for pressure waves. When a gas storage facility experiences a sudden pressure change due to unit fluctuations, the pressure wave can be transmitted to another gas storage facility through the balancing pipeline, rather than being transmitted back to the compressor unit. The pressure balancing valves on the balancing pipelines use special V-type ball valves, whose flow characteristics allow for high flow capacity at small pressure differentials and limited flow capacity at large pressure differentials, automatically achieving selective transmission of pressure waves.

[0130] It can also be a one-way isolation system using a check valve. Specifically, the check valve at the outlet of each compressor unit not only prevents backflow but also blocks the reverse propagation of pressure waves. The check valve employs a low-inertia valve disc design, weighing only 18 kg, and has a response frequency of 5 Hz, enabling it to respond quickly to pressure fluctuations. When a reverse pressure gradient is detected, the valve disc closes within 0.2 seconds, temporarily isolating the unit from the system.

[0131] Furthermore, a second layer of coupling exists between multiple rows of stationary gas generators injecting gas into the same storage facility. The parallel-operating units influence each other; a performance change in one unit will affect the operating point of other units. This can be addressed through a flow balancing control structure. Each row of units is equipped with an independent flow regulating valve (Cv value adjustable range 50-500) at its outlet. The output impedance of each unit is balanced by adjusting the valve opening. When a flow deviation between units is detected to exceed 5%, the regulating valve opening is automatically adjusted. Specifically, for units with excessive flow, the regulating valve opening is reduced, increasing pipeline resistance; for units with insufficient flow, the regulating valve opening is increased, reducing pipeline resistance.

[0132] In some scenarios, the piping of parallel units passes through an 8-meter-long manifold before entering the mixing chamber. The diameter of the manifold (DN600) is 1.414 times larger than the diameter of a single branch pipe (DN400), reducing the flow velocity during merging. Guide vanes are installed inside the manifold to ensure the two airflows converge at a 30-degree angle, avoiding direct impact. The merging point is 3 meters from the mixing chamber inlet, providing sufficient mixing distance.

[0133] Furthermore, a quantitative assessment of the coupling strength is performed. Accordingly, the coupling coefficient K is defined. _couple =ΔP _disturb / ΔP _source ; where ΔP _source For the pressure change of the disturbance source, ΔP _disturb This refers to pressure changes detected by other units.

[0134] K without decoupling measures _couple =0.65-0.78, severe coupling; after using a mixed-flow box, K _couple =0.32-0.45, moderate coupling; K after adding pressure balancing piping _couple =0.15-0.22, slight coupling; K after isolation with check valve _couple =0.05-0.08, basically decoupled.

[0135] In some possible scenarios, assuming that four fixed units are operating at full load, and the flexible units suddenly increase from 0 to 100% load, it is found that after all decoupling measures are implemented, the flow fluctuations of the fixed units are reduced, and the time to restore stability is shortened accordingly; the propagation time of pressure waves from the disturbance source to the farthest unit is reduced, thus improving the system stability margin.

[0136] The above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications, improvements, and substitutions without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A multi-compressor unit coordinated gas injection system for CAES, comprising multiple compressor units, multiple gas storage tanks, and connecting pipelines, characterized in that: Multi-row compressor units include at least one row of stationary compressor units and one row of flexible compressor units; The outlet pipeline of each fixed unit is fixedly connected to the inlet of a corresponding gas storage facility; The outlet pipeline of the flexible unit is connected to the diversion valve group, and the multiple outlets of the diversion valve group are connected to the inlet of each gas storage tank through symmetrically arranged connecting pipelines. Each gas storage unit is equipped with a mixing box at its inlet, where the outlet pipelines of the fixed unit line and the connecting pipelines of the flexible unit line of the corresponding gas storage unit converge. Each compressor unit's outlet pipeline is equipped with a check valve before entering the mixing chamber.

2. The multi-compressor unit coordinated gas injection system for CAES according to claim 1, characterized in that: The flexible unit is configured as a single row. The diversion valve group includes multiple diversion valves corresponding to the number of gas storage tanks. The inlet of each diversion valve is connected to the outlet pipeline of the flexible unit, and the outlet is connected to the mixing box of the corresponding gas storage tank through an independent connecting pipeline. The connecting pipelines from the flexible unit to each gas storage facility have the same diameter and length.

3. The multi-compressor unit coordinated gas injection system for CAES according to claim 1, characterized in that: The number of fixed unit rows can be one or more. When multiple fixed unit rows correspond to the same gas storage facility, the outlet pipelines of these multiple fixed unit rows are connected in parallel to the mixing box of the gas storage facility.

4. The multi-compressor unit coordinated gas injection system for CAES according to claim 1, characterized in that: The mixing chamber is located upstream of the gas storage inlet, and a flow guiding structure is installed inside the mixing chamber; The check valve is installed directly at the interface where the outlet pipeline of each compressor unit enters the mixing box; Each check valve has an independent flow detection device installed on its upstream pipeline.

5. The multi-compressor unit coordinated gas injection system for CAES according to claim 4, characterized in that: The flow detection device is a vortex flow meter or a Coriolis flow meter, and it is installed 0.5-2 meters upstream of the backflow preventer. Each gas storage facility is equipped with a pressure detection device on its inlet header, located in the pipeline section downstream of the mixing box and upstream of the gas storage facility inlet.

6. The multi-compressor unit coordinated gas injection system for CAES according to claim 1, characterized in that: Adjacent gas storage facilities are connected by a pressure balancing pipeline, with both ends of the pressure balancing pipeline connected to the inlet main pipe of the adjacent gas storage facility. A pressure balancing valve is installed on the pressure balancing pipeline. The pressure balancing valve is either an electric regulating valve or a pneumatic regulating valve.

7. The multi-compressor unit coordinated gas injection system for CAES according to any one of claims 1 to 6, characterized in that: Each compressor unit consists of 3 or 4 compressor units connected in series, with adjacent compressor units connected by an interstage cooler. Each compressor unit is equipped with a variable frequency drive and an inlet guide vane adjustment device at the end of the compressor unit.

8. The multi-compressor unit coordinated gas injection system for CAES according to claim 7, characterized in that: Each compressor unit is equipped with an anti-surge valve on its outlet pipe, and the outlet of the anti-surge valve is connected to the inlet pipe of that compressor unit through a return pipe. Each compressor unit is also connected in parallel with a bypass pipeline, and a bypass valve is installed on the bypass pipeline.

9. The multi-compressor unit coordinated gas injection system for CAES according to claim 7, characterized in that: The variable frequency drive unit of the final compressor unit includes a frequency converter and a variable frequency motor; The imported guide vane adjustment device includes an adjustable guide vane mechanism and a guide vane actuator. The adjustable guide vane mechanism is located at the air inlet of the final compressor unit.

10. The multi-compressor unit coordinated gas injection system for CAES according to claim 1, characterized in that: The system also includes a control valve assembly, which includes: Isolation valves installed on the outlet pipeline of each fixed unit; A main isolation valve is installed between the flexible unit row and the diversion valve group; Gas storage isolation valves installed on the inlet header of each gas storage facility; Among them, the isolation valve, the main isolation valve, and the gas storage isolation valve are all electric ball valves or electric butterfly valves.

Images