Novel compressed air storage method

Abstract

The invention relates to the technical field of energy storage, and discloses a novel compressed air storage method which comprises the following steps: step 1, an air storage chamber is constructed underground, the air storage chamber is located in a horizontal tunnel with the depth of 2 kilometers, the diameter of the tunnel is 6 meters, and the horizontal length of the tunnel is 12 kilometers; secondly, air is compressed to 20 MPa step by step through a multi-stage compression system, and the compressed air is conveyed to the air storage chamber through an air inlet pipeline; and thirdly, compressed air is stored in the air storage chamber, the inner wall of the air storage chamber is of a multi-layer structure, the outer layer is high-strength prestressed concrete, the inner layer is an anti-corrosion ceramic coating, and polymer sealing materials are arranged between tunnel segments. The gas storage chambers are established in an underground tunnel mode, limitation of traditional salt cavern gas storage on regional conditions is broken through, dependence on a naturally formed geologic structure is not needed any more, the selection range of the gas storage chambers is greatly expanded, and the method is suitable for wider geographic areas.

Description

Technical Field

[0001] The invention relates to the technical field of energy storage, and in particular to a novel compressed air storage method. Background Art

[0002] With the continuous growth of global energy demand and the increasing proportion of renewable energy in the energy structure, how to effectively store and manage energy has become an important issue in the energy field. Especially in the application of renewable energy such as wind energy and solar energy, the volatility and intermittency of these energy sources lead to instability in their energy supply. This volatility poses a challenge to the stable operation of the power grid. There is an urgent need to find an efficient energy storage method to balance energy supply and demand and ensure the safety and stability of the power system.

[0003] As a mature and efficient energy storage method, air compression energy storage technology has received widespread attention in recent years. CAES technology uses excess electricity during low electricity demand to compress air and store it in underground air storage chambers; during peak electricity demand, compressed air is released to drive turbines to generate electricity, thereby effectively balancing the load of the power grid and improving energy efficiency. This technology can not only achieve energy storage and scheduling, but also effectively alleviate the instability of the power grid caused by fluctuations in renewable energy.

[0004] Traditional CAES systems usually rely on naturally formed underground caverns or abandoned mines as gas storage chambers. While these gas storage chambers provide large-capacity storage space, they also bring a series of technical challenges. First, the gas storage space in underground caverns and mines is often irregular, which makes the gas prone to uneven distribution during storage, affecting the stability and operating efficiency of the system. Secondly, the sealing of the gas storage chamber is difficult to ensure. Due to cracks and pores in the rock formations, the risk of gas leakage is high, especially in the case of long-term high-pressure storage. In addition, although salt cavern gas storage has a slight advantage in terms of sealing, the geographical distribution of salt caverns is limited, and the shape and size of salt caverns are also limited by natural conditions, making it difficult to meet the needs of large-scale energy storage systems.

[0005] With the advancement of technology, people have tried to overcome these problems by transforming underground caves, abandoned mines, and developing other types of artificial gas storage chambers. For example, advanced sealing materials and engineering technologies are used to reinforce and seal underground gas storage chambers to improve their gas storage performance. However, these improvements still have limitations to a certain extent and cannot completely solve the problems of irregular gas storage space, unstable sealing, and limited gas storage capacity. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention provides a novel compressed air storage method, which solves the problems of irregular air storage chamber, unstable sealing and limited air storage capacity in the prior art.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions: A new compressed air storage method comprises the following steps:

[0008] Step 1: construct an underground gas storage chamber, which is located in a horizontal tunnel 2 kilometers deep, with a diameter of 6 meters and a horizontal length of 12 kilometers;

[0009] Step 2: compress the air gradually to 20 MPa through a multi-stage compression system, and transport it to the air storage chamber through an air intake pipe;

[0010] Step 3: Storing compressed air in an air storage chamber, wherein the inner wall of the air storage chamber is composed of a multi-layer structure, the outer layer is high-strength prestressed concrete, the inner layer is an anti-corrosion ceramic coating, and a polymer sealing material is arranged between the tunnel segments;

[0011] Step 4: When the compressed air needs to be released, the compressed air is guided to the generator set through the exhaust pipe to generate electricity, and the exhaust pipe is provided with a dynamic flow control valve and a flow rate sensor;

[0012] Step 5: Use a hydraulic balance system to drive the compressed air out of the air storage chamber through the water pressure in the ground water tank;

[0013] Step 6: Convert the remaining kinetic energy of the compressed air into electrical energy through the residual pressure recovery device.

[0014] Preferably, the multi-layer structure of the air storage chamber includes an outer prestressed concrete layer, the thickness of the prestressed concrete layer is 0.5 meters, the inner layer is an anti-corrosion ceramic coating with a thickness of 5 millimeters, and an anti-leakage protective layer is arranged between the prestressed concrete layer and the anti-corrosion ceramic coating, the anti-leakage protective layer is made of a high-density polymer composite material, and its thickness is 20 millimeters.

[0015] Preferably, the polymer sealing material comprises a thermosetting elastomer material with high pressure resistance and self-healing properties, which has adhesion when filled between tunnel segments and can automatically repair cracks caused by slight deformation under high pressure environment.

[0016] Preferably, the multi-stage compression system includes a five-stage compressor, each stage of the compressor is connected to an intercooler, and the intercooler performs heat exchange through a cooling circulation system. The temperature of the cooled air is controlled to drop below 25°C after each stage of compression. The cooling circulation system adopts a closed circulation structure.

[0017] Preferably, waste heat in the cooling circulation system is recovered through a heat exchanger, which is connected to a heating pipe in the stratum surrounding the tunnel. The heating pipe is arranged around the outer wall of the air storage chamber to adjust the temperature difference between the tunnel and the outside world.

[0018] Preferably, the gas storage chamber is divided into multiple independent sections, each section is 2 kilometers long, and the sections are separated by high-pressure resistant isolation valves. The isolation valves are controlled by an automatic control system to automatically close the valves of the relevant sections when the air pressure fluctuates or leaks.

[0019] Preferably, the gas pressure monitoring system includes a plurality of pressure sensors installed on the inner wall of each section of the gas storage chamber. The pressure sensors communicate with the central control system via a wireless network and transmit gas pressure data in real time. The central control system analyzes the pressure status of each section based on the received data and initiates corresponding emergency measures when an abnormality is found.

[0020] Preferably, a dynamic flow regulating valve is provided in the exhaust duct, and the regulating valve is driven by a servo motor. The opening of the regulating valve is adjusted in real time by the central control system according to the data collected by the flow velocity sensor. The flow velocity sensor is installed in the exhaust duct near the inlet of the generator set, and can detect the flow velocity of the compressed air passing through the duct and feed back the flow velocity data to the central control system.

[0021] Preferably, the central control system is also connected to a multi-stage turbine generator set, which includes three turbine stages. The rotation speed of each turbine stage is controlled by the central control system to adapt to different pressures and flows of compressed air. The central control system dynamically adjusts the power output of each stage of the turbine according to the flow rate sensor data in the exhaust duct to maximize the power generation efficiency.

[0022] Preferably, the air quality in the air storage chamber is monitored by a multi-point sensor network, which includes a humidity sensor, a temperature sensor and a particulate matter sensor. The sensors are installed at key positions of each section of the air storage chamber. The data of the sensors are transmitted to the central control system through a wireless communication module. When the air quality drops to a predetermined threshold, the system automatically starts the drain valve to discharge part of the air, and simultaneously starts the air filtration system to maintain the air quality.

[0023] The present invention provides a novel compressed air storage method, which has the following beneficial effects:

[0024] 1. The present invention breaks through the limitations of traditional salt cavern gas storage on geographical conditions by establishing a gas storage chamber in the form of an underground tunnel. It no longer relies on naturally formed geological structures, greatly expands the selection range of gas storage chambers, and is suitable for a wider geographical area.

[0025] 2. The present invention adopts a multi-layer structure design of cement segments and high-performance sealing layers, which effectively overcomes the defect of unstable sealing of traditional salt caverns. The structural design of cement segments not only enhances the sealing of the gas storage chamber, but also greatly improves its pressure resistance and overall safety, ensuring the long-term stability of the gas storage chamber under high pressure conditions.

[0026] 3. By utilizing the natural pressure of water, the gas storage system designed by the present invention can maintain a constant pressure of 20MPa when the compressed air is discharged, ensuring that the gas in the gas storage chamber can be completely discharged, overcoming the problem of the traditional salt caverns gradually decreasing pressure during the exhaust process and being unable to be completely emptied, thereby improving the power generation efficiency and energy utilization rate of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the layout of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1:

[0030] Please see attached Figure 1 The embodiment of the present invention provides a novel compressed air storage method, comprising the following steps:

[0031] 1. Construction and sealing technology of air storage chamber

[0032] 1.1 Construction of underground tunnel

[0033] In this embodiment, the construction of the underground tunnel first requires comprehensive geological exploration. In order to ensure the safety and long-term stability of the tunnel, the geological exploration uses a variety of high-precision equipment, such as geological radar, seismic wave reflection method, and drilling sampling. These technologies can analyze in detail the rock structure, geological fault zones, hydrological conditions and potential geological risks at a depth of 2 kilometers underground, thereby providing a scientific basis for tunnel construction.

[0034] After determining the appropriate tunnel path, a shield machine was used to excavate the tunnel. The diameter of the tunnel is 6 meters and the horizontal length is 12 kilometers. During the excavation process, the shield machine advances forward at a certain speed and simultaneously completes the support of the tunnel wall. Due to the high pressure environment 2 kilometers underground, it is necessary to install temporary support structures around the tunnel in time while the shield machine advances, using methods such as steel frame support and shotcrete to prevent tunnel collapse and soil flow.

[0035] When the tunnel excavation is completed, the prefabricated cement segments are installed immediately. The cement segments are made of high-strength prestressed concrete with a thickness of 0.5 meters. They are designed to withstand the huge underground pressure and long-term geological stress changes. Each segment is connected by high-strength bolts and rubber sealing rings to ensure a tight connection between the segments and form a continuous tunnel lining. After the segments are spliced, grouting treatment is required to further enhance the stability and sealing of the tunnel wall.

[0036] In order to ensure the construction safety and stability of underground tunnels in later use, the deformation of the tunnel needs to be monitored in real time during the construction process. Use equipment such as laser rangefinders, strain gauges and multi-point displacement sensors to precisely monitor the lateral and longitudinal deformation of the tunnel. Any abnormal deformation data will be transmitted to the construction command center, and construction personnel can make adjustments based on real-time data to ensure that the tunnel does not deform beyond expectations during excavation and segment installation. After the segment installation is completed, a pressure test is carried out to verify the overall sealing and pressure-bearing capacity of the tunnel. The pressure test simulates the high-pressure environment in the tunnel by pressurizing it to check whether the sealing effect of the tunnel meets the design requirements.

[0037] 1.2 Design of multi-layer structure

[0038] In this embodiment, the inner wall of the air storage chamber adopts a multi-layer structure design to enhance its sealing and durability under high pressure environment. Specifically, the inner wall of the air storage chamber is divided into three layers, namely a prestressed concrete layer, an anti-leakage protection layer and an anti-corrosion ceramic coating.

[0039] Outer layer (prestressed concrete layer): The thickness of the prestressed concrete layer is 0.5 meters. This layer uses a combination of prestressed steel bars and high-strength concrete to pre-stress to resist the long-term stress caused by underground pressure. The prestressed concrete layer not only provides the necessary pressure bearing capacity, but also ensures the structural stability of the tunnel in long-term operation.

[0040] Middle layer (anti-leakage protection layer): The anti-leakage protection layer is made of high-density polymer composite material with a thickness of 20 mm. This material has high ductility and self-healing properties. When the tunnel structure is affected by external forces or geological stress, it can automatically repair tiny cracks to prevent gas leakage and ensure the long-term sealing of the tunnel. In addition, this layer also has excellent chemical corrosion resistance and can effectively resist the erosion of groundwater and other chemicals.

[0041] Inner layer (anti-corrosion ceramic coating): The thickness of the anti-corrosion ceramic coating is 5 mm, which is evenly covered on the anti-leakage protective layer through a spraying process. The main function of the ceramic coating is to prevent the erosion of the inner wall of the tunnel by groundwater and other corrosive substances and provide additional mechanical protection. The surface of the ceramic coating is polished to ensure its smoothness to reduce friction losses during air flow.

[0042] In order to ensure the close combination of each layer of materials, a segmented construction process is adopted during construction. The specific steps are:

[0043] First, the prestressed concrete layer is installed to ensure it is fully cured and reaches its designed strength.

[0044] Secondly, an anti-leakage protective layer is evenly coated on the surface of the concrete layer to ensure good adhesion between the material and the concrete layer, and a self-healing performance test is carried out.

[0045] Finally, the anti-corrosion ceramic coating is applied using high-precision spraying equipment, and the curing process of the coating is controlled by temperature control technology to ensure the flatness and sealing of the coating surface.

[0046] 1.3 Segmented design of air storage chamber

[0047] In this embodiment, in order to further improve the safety and operational flexibility of the gas storage chamber, the tunnel is divided into multiple independent sections, each with a length of 2 kilometers. The sections are separated by high-strength isolation valves, which are made of high-pressure resistant materials and managed by an automatic control system. The isolation valves can quickly close the affected sections in the event of pressure fluctuations or leakage, preventing gas leakage from spreading to other sections.

[0048] An independent gas pressure monitoring system is installed in each section. The system consists of multiple pressure sensors distributed in different locations of the section to monitor the gas pressure status in the section. The pressure sensor is connected to the central control system through a wireless network to transmit data in real time. The central control system can analyze and process the received data, and when abnormal gas pressure is detected, it automatically activates the isolation valve of the relevant section and closes the section to prevent further leakage or accidents.

[0049] When designing and constructing these sections, full consideration was given to the pressure balance and airflow characteristics between the sections. The design of the air storage chamber ensures that when an abnormality occurs in any section, it will not affect the normal operation of other sections. The independent design between the sections also facilitates future maintenance and overhaul. Through this segmented design, repairs and maintenance can be carried out on a single section without interrupting the operation of the entire system, thereby improving the operating efficiency and safety of the system.

[0050] 2. Compression and storage of compressed air

[0051] 2.1 Multi-stage compression system

[0052] In this embodiment, the air is compressed using a five-stage compression system. Before entering the compression system, the air first passes through a high-efficiency filtering device to remove large particles of impurities and moisture in the air. The filtering system includes a coarse filter and a fine filter. The coarse filter is used to initially remove large particles of matter in the air, such as dust, sand, etc., and the fine filter is used to further remove fine particles and trace moisture to ensure that the air entering the compressor is clean and reduce wear and damage to the compressor.

[0053] The filtered air enters the first compressor for initial compression. The compressed air temperature rises. To prevent the high temperature from damaging the compressor and pipelines, the compressed air will be cooled by the intercooler. The intercooler adopts a closed circulation cooling system. The coolant circulates in the closed pipeline, cooling the air while transferring heat to the heat exchanger. After the coolant is cooled by the heat exchanger, it returns to the cooler for recycling. This system design effectively reduces the evaporation and heat loss of the coolant, improves the cooling efficiency, and keeps the air temperature below 25°C.

[0054] After the air is cooled, it continues to enter the second compressor for secondary compression and repeats the above cooling process. This process is carried out in sequence until the air is compressed to 20MPa step by step. The air after each stage of compression will be cooled to a relatively low temperature to prevent high temperature from damaging the compressor and pipeline.

[0055] In the compression system, multi-stage compression and intermediate cooling technology are used, which can not only significantly improve the air compression efficiency, but also effectively control the air temperature, reduce energy loss and equipment wear. At the same time, the cooling system monitors the temperature and pressure of the coolant in real time to ensure that the cooling system can automatically adjust the cooling intensity according to actual needs while operating efficiently, ensuring the stability and safety of the compressed air.

[0056] 2.2 Waste heat recovery

[0057] In this embodiment, a large amount of waste heat is generated during the compression process of air, which is recovered by the heat exchanger of the cooling system and used to heat the ground around the tunnel. The heat exchanger conducts heat to the heating pipe on the outer wall of the air storage chamber through a heat-conducting pipe. The heating pipe is arranged around the outer wall of the air storage chamber. The temperature of the outer wall of the tunnel is controlled by adjusting the heat flow in the pipe, thereby reducing the structural stress caused by the temperature difference and preventing the formation of cracks in the tunnel due to stress concentration caused by the temperature difference.

[0058] The waste heat recovery system can not only effectively utilize the waste heat in the compression process, but also extend the service life of the tunnel and reduce maintenance costs by regulating the temperature of the tunnel structure. In winter, the waste heat recovery system can also be used to prevent freezing of ground water tanks. The antifreeze system transfers heat to the water in the ground water tank through underground pipes, keeps the water temperature above 0°C, prevents the water tank from freezing, and ensures stable operation of the system in cold climate conditions.

[0059] The design of the waste heat recovery system fully considers the impact of ambient temperature and seasonal changes on the system. Through the intelligent control system, it can automatically adjust the distribution and use of waste heat according to actual needs, maximize the utilization of waste heat resources, and improve the overall energy efficiency of the system.

[0060] 2.3 Air Quality Management

[0061] In this embodiment, in order to ensure the quality of compressed air in the air storage chamber, the air must be processed by a high-efficiency filtration system before compression. The filtration system includes two stages of filtration: the first stage is a coarse filter, which is used to remove large particles of impurities in the air, such as dust, sand, etc.; the second stage is a fine filter, which is used to remove fine particles and moisture in the air to ensure that the air entering the compressor is clean.

[0062] After the air is compressed and stored in the air storage chamber, the system monitors the air quality in the air storage chamber in real time through a multi-point sensor network. The sensor network includes humidity sensors, temperature sensors, and particulate matter sensors, which are installed at key locations in each section of the air storage chamber. The sensor data is transmitted to the central control system in real time through the wireless communication module. The central control system analyzes the data. Once it detects that the air quality drops to a predetermined threshold, the system automatically starts the drain valve to discharge part of the air, and at the same time starts the air filtration system to filter and process the discharged air.

[0063] In addition, the central control system also has the function of automatically adjusting the air quality. When the sensor detects that the air quality does not meet the standard, the system will automatically adjust the working status of the filtration system based on real-time monitoring data, including adjusting the cleaning frequency and replacement cycle of the filter, to ensure that the air in the air storage room is always kept within the appropriate quality range.

[0064] Through this efficient air quality management measure, the purity of the air in the gas storage room is ensured, the risk of equipment damage due to air quality problems is reduced, and the service life of the gas storage system is extended.

[0065] 3. Release of compressed air and power generation

[0066] 3.1 Dynamic Exhaust Control

[0067] In this embodiment, when compressed air needs to be released for power generation, the central control system will adjust the air flow rate by controlling the dynamic flow control valve in the exhaust pipe. The exhaust pipe is made of high-strength alloy steel lined with ceramics. The ceramic lining can not only withstand the impact of high-pressure air, but also reduce the friction loss of air when it flows in the pipe, thereby improving the energy efficiency of the system.

[0068] The flow rate sensor is installed in the exhaust pipe near the generator set inlet to monitor the compressed air flow rate through the pipe in real time and feed the data back to the central control system. The central control system adjusts the opening of the flow control valve according to the data of the flow rate sensor to ensure that the compressed air enters the generator set at a stable pressure and flow rate, avoiding system instability caused by too fast or too slow flow rate.

[0069] Dynamic flow control is adjusted through the intelligent algorithm of the central control system. Combined with the air pressure state in the air storage chamber and the power generation demand, the system can automatically optimize the exhaust speed and pressure to ensure that the generator set can operate in the optimal state. In addition, the system also has an abnormality handling function. Once an abnormal flow rate or air pressure fluctuation is detected, the system will automatically adjust the opening of the flow valve and issue an alarm to remind the operator to prevent possible failures or accidents.

[0070] In order to improve the safety of the system, the central control system is also equipped with a backup control strategy. When the main control strategy fails or malfunctions, the backup control strategy can automatically take over the operation of the system to ensure the continued stability and safety of the system.

[0071] 3.2 Multi-stage turbine power generation and residual pressure recovery

[0072] In this embodiment, compressed air is used to generate electricity through a multi-stage turbine generator set. The multi-stage turbine generator set consists of three turbine stages, and the speed and power output of each turbine stage are controlled by a central control system to adapt to compressed air of different pressures and flows. Specifically, the compressed air first enters the first-stage turbine to generate preliminary electrical energy under high pressure. Then, the air enters the second-stage turbine to further release energy, reduce pressure and temperature, and generate more electricity. Finally, the air enters the third-stage turbine to use the remaining kinetic energy for final power generation.

[0073] The speed and power output of each stage of the turbine are dynamically adjusted according to the pressure and flow of the air, ensuring that the turbine unit always operates at the best efficiency. The multi-stage turbine power generation structure can fully utilize the kinetic energy of compressed air, efficiently convert it into electrical energy, and reduce energy waste.

[0074] In addition, after the compressed air is used to generate electricity, the remaining residual pressure is further converted into electrical energy through the residual pressure recovery device. The residual pressure recovery device uses small turbine power generation technology to convert the remaining kinetic energy into electrical energy, thereby further improving the overall energy efficiency of the system. The design of the residual pressure recovery device takes into account the dynamic characteristics of the gas, ensuring that the residual pressure can be effectively utilized at different pressures to reduce energy waste. The power output of the residual pressure recovery system is integrated into the overall power management of the system, further improving the energy utilization rate of the system.

[0075] 3.3 Automatic control and remote management

[0076] In this embodiment, the entire compressed air storage and release process is automatically controlled by a PLC (Programmable Logic Controller) and a SCADA (Supervisory Control and Data Acquisition) system. The PLC system is responsible for the operation and control of each subsystem, such as the compressor, cooler, valve, turbine generator set, etc. The SCADA system is responsible for data acquisition, monitoring and fault diagnosis of the entire system, and supports remote operation.

[0077] Through the SCADA system, operators can monitor the operating status of the entire system in real time at the control center, including the data of each sensor, the working status of the compressor and the generator set, etc. The SCADA system can analyze the operating data of each subsystem in real time and automatically generate an operating report. The report content includes the stability of system operation, energy efficiency analysis, and early warning information of potential failures.

[0078] When an abnormality occurs in the system, the SCADA system will sound an alarm and automatically shut down according to the preset emergency plan to prevent further failure or damage to the system. The system's emergency plan includes a variety of emergency response solutions, such as automatically switching to backup equipment, starting the cold standby system, and adjusting operating parameters to ensure that the system can still maintain stable operation in an emergency.

[0079] In addition, the SCADA system also has a remote monitoring function, allowing operators to view the system operation status in real time through the Internet, and perform remote operations and adjustments when necessary to ensure the safety and stability of the system. The remote management function provides operators with greater flexibility, enabling them to monitor and manage the operation of the system anytime and anywhere, thereby improving the management efficiency and safety of the system.

[0080] Embodiment 2:

[0081] In this embodiment, based on the first embodiment, the second embodiment adopts a variable, namely the depth and length of the tunnel. The tunnel depth in this embodiment is 1.5 kilometers and the horizontal length is 8 kilometers. Compared with the first embodiment, the depth and length of the tunnel are reduced. This adjustment has a certain impact on the performance of the overall system, which specifically includes the following steps:

[0082] 1. Construction and sealing technology of air storage chamber

[0083] 1.1 Construction of underground tunnel

[0084] In this embodiment, the construction of the underground tunnel still follows the same geological exploration and construction process as in the first embodiment, but the depth and length of the tunnel are reduced. The depth of the tunnel is 1.5 kilometers and the horizontal length is 8 kilometers. The geological exploration process also uses geological radar, seismic wave reflection method, and drilling sampling methods to ensure that the stability of the tunnel can be guaranteed at a shallow depth.

[0085] As the tunnel depth is reduced, the construction pressure of the shield machine is reduced, but as the length is shortened, the gas storage capacity of the tunnel is also reduced accordingly. The construction process still requires the installation of temporary support structures, and the prefabricated cement segments are installed immediately after the tunnel excavation is completed. The material and installation method of the cement segments are the same as those in Example 1, ensuring the structural strength and stability of the tunnel.

[0086] 1.2 Design of multi-layer structure

[0087] In this embodiment, the multi-layer structure design of the inner wall of the gas storage chamber is consistent with that of the first embodiment, and still adopts a three-layer structure of a prestressed concrete layer, an anti-leakage protective layer and an anti-corrosion ceramic coating. The thickness and material properties of each layer remain unchanged to ensure that the tunnel can still maintain good sealing and durability when the depth and length are reduced.

[0088] 1.3 Segmented design of air storage chamber

[0089] Similar to the first embodiment, the tunnel in this embodiment is still divided into multiple independent sections, but due to the reduction in the length of the tunnel, the length of each section and the total number of sections are adjusted accordingly. Specifically, the tunnel is divided into 4 sections, each of which is 2 kilometers long. The isolation valves between sections, the gas pressure monitoring system and other designs remain unchanged to ensure that the operation of each section can be automatically isolated and controlled when an abnormal gas pressure occurs.

[0090] 2. Compression and storage of compressed air

[0091] 2.1 Multi-stage compression system

[0092] In this embodiment, the multi-stage compression system of compressed air is consistent with that in the first embodiment. After being efficiently filtered, the air is still gradually compressed to 20MPa by a five-stage compressor and cooled by an intercooler. As the length and depth of the tunnel are reduced, the total capacity of the air storage chamber is reduced, resulting in a reduction in the overall air storage capacity of the system.

[0093] 2.2 Waste heat recovery

[0094] In this embodiment, the waste heat recovery system is consistent with that in the first embodiment. The waste heat generated during the compression process is recovered through a heat exchanger and used for ground heating around the tunnel and antifreeze treatment of the ground water reservoir. However, due to the reduction in tunnel length and depth, the effective area of ​​the waste heat recovery system is also reduced, and the corresponding waste heat utilization rate is slightly reduced.

[0095] 2.3 Air Quality Management

[0096] The air quality management system is the same as in the first embodiment, and still includes a coarse filter and a fine filter, as well as a multi-point sensor network for real-time monitoring and an air quality maintenance mechanism of a central control system. Due to the reduction in the capacity of the air storage chamber, the system's air quality management requirements are reduced accordingly, but the overall functions and performance remain the same.

[0097] 3. Release of compressed air and power generation

[0098] 3.1 Dynamic Exhaust Control

[0099] The dynamic exhaust control system in this embodiment is consistent with that in the first embodiment. The central control system still controls the discharge speed of compressed air through the flow rate sensor and the flow regulating valve to ensure the stable operation of the generator set. Although the tunnel capacity is reduced, the system can still effectively control the release of compressed air and maintain the power generation efficiency.

[0100] 3.2 Multi-stage turbine power generation and residual pressure recovery

[0101] In this embodiment, the multi-stage turbine power generation and residual pressure recovery system are the same as those in the first embodiment. Compressed air is used to generate electricity through the multi-stage turbine generator set, and the remaining residual pressure is converted into electrical energy through the residual pressure recovery device. However, due to the reduction in the capacity of the air storage chamber, the total kinetic energy of the compressed air is correspondingly reduced, resulting in a slight reduction in the total power generation of the system.

[0102] 3.3 Automatic control and remote management

[0103] The automatic control and remote management system are consistent with the first embodiment. The PLC system and SCADA system are responsible for the automatic control, monitoring and fault diagnosis of the entire compressed air storage and release process, and the remote management function ensures the safety and stability of the system operation.

[0104] Embodiment three:

[0105] In this embodiment, based on the first embodiment, the third embodiment adopts a variable, namely, the number of compressor stages. The compressor system in this embodiment is adjusted from five-stage compression to four-stage compression. Compared with the first embodiment, the number of compressor stages is reduced. This adjustment has a certain impact on the compression efficiency and energy utilization of the overall system, and specifically includes the following steps:

[0106] 1. Construction and sealing technology of air storage chamber

[0107] 1.1 Construction of underground tunnel

[0108] In this embodiment, the construction of the underground tunnel is exactly the same as in the first embodiment. The depth of the tunnel is still 2 kilometers and the horizontal length is 12 kilometers. The tunnel excavation, support structure installation, cement segment prefabrication and installation, and real-time monitoring of tunnel deformation are the same as in the first embodiment. The structural strength, sealing, and overall stability of the tunnel are still fully guaranteed.

[0109] 1.2 Design of multi-layer structure

[0110] The multi-layer structure design of the inner wall of the gas storage chamber is consistent with that of the first embodiment, and still adopts a three-layer structure of a prestressed concrete layer, an anti-leakage protective layer and an anti-corrosion ceramic coating. The thickness and material properties of each layer are the same as those of the first embodiment, ensuring the sealing and durability of the tunnel under high pressure environment.

[0111] 1.3 Segmented design of air storage chamber

[0112] The segmentation design of the tunnel is also consistent with the first embodiment. The tunnel is still divided into 6 sections, each of which is 2 kilometers long. The isolation valves between sections and the gas pressure monitoring system remain unchanged to ensure that the operation of each section can be automatically isolated and controlled in the event of abnormal gas pressure.

[0113] 2. Compression and storage of compressed air

[0114] 2.1 Multi-stage compression system

[0115] In this embodiment, the multi-stage compression system of compressed air is adjusted from five-stage compression to four-stage compression. The air still passes through a high-efficiency filtering device before entering the compression system to remove large particles of impurities and moisture. The filtering system includes a coarse filter and a fine filter to ensure that the air entering the compressor is clean and reduce wear and damage to the compressor.

[0116] The filtered air enters the four-stage compressor for compression step by step. As the number of compression stages decreases, the compression ratio of each stage increases, resulting in a relatively large increase in the temperature of the air after each stage of compression. In order to prevent high temperature from damaging the compressor and pipelines, the compressed air is still cooled by the intercooler, but due to the reduction in the number of stages, the load of the cooler increases. Despite this, the air can still reach a compression pressure of 20MPa after four stages of compression.

[0117] While the four-stage compression system reduces equipment complexity, it also reduces the efficiency of the compression process, especially in terms of energy consumption and air temperature control. The system requires more efficient cooling devices to handle the increased heat load, and the energy loss in the compression process increases.

[0118] 2.2 Waste heat recovery

[0119] The waste heat recovery system is consistent with the first embodiment. Although the number of compressor stages is reduced, resulting in an increase in waste heat generated by the system, the waste heat recovery system still effectively recovers this waste heat through the heat exchanger and uses it for heating the strata around the tunnel and antifreezing treatment of the ground water reservoir. Due to the reduction in the number of compression stages, the thermal efficiency of the compression process is reduced, resulting in the overall waste heat recovery efficiency of the system being slightly lower than that of the first embodiment.

[0120] 2.3 Air Quality Management

[0121] The air quality management system is the same as that in the first embodiment, and still includes a coarse filter and a fine filter, as well as a real-time monitoring of a multi-point sensor network and an air quality maintenance mechanism of a central control system. Although the number of compressor stages is reduced, the requirements for air quality management remain unchanged, and the system can still effectively ensure the cleanliness of the air in the air storage room and the long-term stable operation of the system.

[0122] 3. Release of compressed air and power generation

[0123] 3.1 Dynamic Exhaust Control

[0124] The dynamic exhaust control system in this embodiment is consistent with that in the first embodiment. The central control system still controls the discharge speed of compressed air through the flow rate sensor and the flow regulating valve to ensure the stable operation of the generator set. Although the number of compressor stages is reduced, the system can still effectively control the release of compressed air and maintain the power generation efficiency.

[0125] 3.2 Multi-stage turbine power generation and residual pressure recovery

[0126] In this embodiment, the multi-stage turbine power generation and residual pressure recovery system are the same as those in the first embodiment. Compressed air is used to generate electricity through the multi-stage turbine generator set, and the remaining residual pressure is converted into electrical energy through the residual pressure recovery device. However, due to the reduction in the number of compressor stages, the energy consumption of the compression process is relatively high, resulting in the total power generation of the system being slightly lower than that of the first embodiment.

[0127] 3.3 Automatic control and remote management

[0128] The automatic control and remote management system are consistent with the first embodiment. The PLC system and SCADA system are responsible for the automatic control, monitoring and fault diagnosis of the entire compressed air storage and release process, and the remote management function ensures the safety and stability of the system operation.

[0129] Table 1 Comparison table of experimental data of embodiment

[0130]

[0131] Embodiment 1 is superior to Embodiment 2 and Embodiment 3 in terms of key performance indicators. Although its construction cost and equipment complexity are higher, its system energy efficiency, total power generation and operational stability are more advantageous, and it is suitable for application scenarios of efficient energy storage and power generation.

[0132] Comparative Example:

[0133] The following is a detailed description of the steps of a traditional compressed air storage system. These steps are based on the common design of a traditional system, which uses underground caves or abandoned mines as air storage chambers for compressed air storage and release. Specifically, the following steps are included:

[0134] 1. Construction and sealing technology of air storage chamber

[0135] 1.1 Choice of underground caves / abandoned mines

[0136] In traditional systems, gas storage chambers usually utilize existing underground caverns or abandoned mines. These underground structures have been formed naturally and have large spatial capacity, which is suitable for storing compressed air. When selecting a gas storage chamber, the underground caverns or abandoned mines are first geologically surveyed to evaluate their structural stability, sealing, and suitability for long-term gas storage. Due to the irregular shapes of these natural spaces and poor sealing, further processing is required.

[0137] 1.2 Sealing treatment

[0138] In order to improve the sealing of underground caves or abandoned mines, the traditional method is usually to spray waterproof coatings on the inner walls of caves or mines, or use polymer materials for sealing. These materials can fill the cracks and pores in natural caves to prevent gas leakage. However, due to the irregularity and complexity of underground space, the sealing effect is usually not as stable as that of artificial tunnel structures.

[0139] 1.3 Renovation of the gas storage chamber

[0140] After sealing, conventional systems will make necessary modifications to the gas storage chamber, such as installing support structures to prevent cavern collapse or reinforcing tunnels in mines. The purpose of the modification is to improve the safety and stability of underground gas storage space to meet the needs of long-term high-pressure gas storage.

[0141] 2. Compression and storage of compressed air

[0142] 2.1 Multi-stage compression system

[0143] The compressed air of the traditional system is usually completed through a three-stage compression system. The air is first filtered to remove large particles and then enters the first compressor for initial compression. The compressed air temperature rises, and after cooling through the intercooler, it enters the second compressor for further compression. This process is repeated until the air is compressed to a pressure of about 10MPa.

[0144] Due to the small number of compression stages, the compression efficiency of the traditional system is low, and the air temperature is high during the compression process, requiring stronger cooling to prevent the system from overheating. The cooling system usually adopts an open cycle, the coolant evaporation loss is large, and the cooling efficiency is relatively low.

[0145] 2.2 Air Storage

[0146] The compressed air is transported through pipelines to underground caves or abandoned mines for storage. Due to the poor sealing of the air storage chamber, the traditional system will have a certain degree of gas leakage, especially during long-term storage. For this reason, the system needs to regularly check the air tightness of the air storage chamber and perform necessary maintenance and repairs.

[0147] 2.3 Air Quality Management

[0148] Air quality management is relatively simple in traditional systems, mainly relying on primary filters to remove large particles of impurities in the air. Air quality monitoring is mainly focused on pressure monitoring in the air storage chamber to ensure that the air pressure in the air storage chamber remains within the design range to prevent overpressure or leakage accidents. Compared with modern systems, the air quality management and monitoring methods of traditional systems are relatively extensive and cannot accurately control the air composition and quality.

[0149] 3. Release of compressed air and power generation

[0150] 3.1 Simple exhaust control

[0151] The exhaust control of traditional systems is relatively simple, usually relying on manual valves or mechanical control valves to adjust the release rate of compressed air. These control devices usually do not have automation or real-time adjustment functions, resulting in inefficiency and instability in the system during operation.

[0152] 3.2 Single-stage turbine power generation

[0153] In traditional systems, compressed air is usually used to generate electricity through a single-stage turbine generator set. The compressed air enters the turbine and drives the generator to generate electricity. Due to the relatively low pressure and unstable air flow, the power generation efficiency is usually low and the energy conversion efficiency is limited. The residual energy that is not fully utilized in the power generation process is often directly discharged without further recovery and utilization.

[0154] 3.3 Basic control and monitoring

[0155] The control and monitoring functions of traditional systems are relatively basic, usually relying on manual operation and regular inspections. The operation of the entire system relies on manual control, and the monitoring methods mainly include barometers and thermometers. The real-time data collection and automatic adjustment functions are weak. When a fault or abnormality occurs, it is necessary to rely on manual troubleshooting and repair, and it is impossible to respond or warn quickly, resulting in low system operation reliability.

[0156] Table 2 Comparison table of comparative experimental data

[0157] Embodiment 1 Comparative Example Compressed air pressure (MPa) 2 10 Waste heat recovery efficiency (%) 85 80 System energy efficiency (%) 70 45 Total power generation (MWh) 1200 500 Compression process energy consumption (MWh) 400 350 Operation stability (score / 10) 9 6

[0158] Compared with the traditional compressed air storage system, the first embodiment significantly improves the system's gas storage capacity, energy efficiency and power generation capacity by using underground tunnels as air storage chambers and combining more efficient compression and waste heat recovery technologies. Although its equipment complexity and construction costs have increased, these investments have resulted in higher system performance and stability, giving it a clear advantage in modern energy storage and utilization.

[0159] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A novel compressed air storage method, characterized in that: The following steps are involved: Step 1: construct an underground gas storage chamber, which is located in a horizontal tunnel 2 kilometers deep, with a diameter of 6 meters and a horizontal length of 12 kilometers; Step 2: compress the air gradually to 20 MPa through a multi-stage compression system, and transport it to the air storage chamber through an air intake pipe; Step 3: Storing compressed air in an air storage chamber, wherein the inner wall of the air storage chamber is composed of a multi-layer structure, the outer layer is high-strength prestressed concrete, the inner layer is an anti-corrosion ceramic coating, and a polymer sealing material is arranged between the tunnel segments; Step 4: When the compressed air needs to be released, the compressed air is guided to the generator set through the exhaust pipe to generate electricity, and the exhaust pipe is provided with a dynamic flow control valve and a flow rate sensor; Step 5: Use a hydraulic balance system to drive the compressed air out of the air storage chamber through the water pressure in the ground water tank; Step 6: Convert the remaining kinetic energy of the compressed air into electrical energy through the residual pressure recovery device.

2. A novel compressed air storage method according to claim 1, characterized in that: The multi-layer structure of the air storage chamber includes an outer prestressed concrete layer, the thickness of which is 0.5 meters, an inner layer of an anti-corrosion ceramic coating with a thickness of 5 millimeters, and an anti-leakage protective layer is arranged between the prestressed concrete layer and the anti-corrosion ceramic coating. The anti-leakage protective layer is made of a high-density polymer composite material and has a thickness of 20 millimeters.

3. A novel compressed air storage method according to claim 1, characterized in that: The polymer sealing material includes a thermosetting elastomer material with high pressure resistance and self-healing properties. The material has adhesion when filled between tunnel segments and can automatically repair cracks caused by slight deformation under high pressure environment.

4. A novel compressed air storage method according to claim 1, characterized in that: The multi-stage compression system includes a five-stage compressor, each stage of the compressor is connected to an intercooler, and the intercooler performs heat exchange through a cooling circulation system. The temperature of the cooled air is controlled to drop below 25°C after each stage of compression. The cooling circulation system adopts a closed circulation structure.

5. A novel compressed air storage method according to claim 1, characterized in that: The waste heat in the cooling circulation system is recovered through a heat exchanger, which is connected to a heating pipe in the ground around the tunnel. The heating pipe is arranged around the outer wall of the air storage chamber to adjust the temperature difference between the tunnel and the outside world.

6. A novel compressed air storage method according to claim 1, characterized in that: The gas storage chamber is divided into multiple independent sections, each section is 2 kilometers long, and the sections are separated by high-pressure resistant isolation valves. The isolation valves are controlled by an automatic control system, which automatically close the valves of the relevant sections when the air pressure fluctuates or leaks.

7. A novel compressed air storage method according to claim 1, characterized in that: The gas pressure monitoring system includes multiple pressure sensors installed on the inner walls of each section of the gas storage chamber. The pressure sensors communicate with the central control system via a wireless network and transmit gas pressure data in real time. The central control system analyzes the pressure status of each section based on the received data and initiates corresponding emergency measures when an abnormality is found.

8. A novel compressed air storage method according to claim 1, characterized in that: A dynamic flow regulating valve is provided in the exhaust duct. The regulating valve is driven by a servo motor, and its opening is adjusted in real time by the central control system according to the data collected by the flow velocity sensor. The flow velocity sensor is installed in the exhaust duct near the inlet of the generator set, and can detect the flow velocity of compressed air passing through the duct and feed back the flow velocity data to the central control system.

9. A novel compressed air storage method according to claim 1, characterized in that: The central control system is also connected to a multi-stage turbine generator set, which includes three turbine stages. The speed of each turbine stage is controlled by the central control system to adapt to different pressures and flows of compressed air. The central control system dynamically adjusts the power output of each stage of the turbine based on the flow rate sensor data in the exhaust duct.

10. A novel compressed air storage method according to claim 1, characterized in that: The air quality in the air storage chamber is monitored by a multi-point sensor network, which includes a humidity sensor, a temperature sensor and a particle sensor. The sensors are installed at key positions in each section of the air storage chamber. The data of the sensors are transmitted to the central control system through a wireless communication module. When the air quality drops to a predetermined threshold, the system automatically starts the drain valve to discharge part of the air, and at the same time starts the air filtration system to maintain the air quality.

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