A compressed air energy storage system and preheat control method to prevent water and salt precipitation

Abstract

The present application relates to the technical field of air energy storage, and particularly relates to a compressed air energy storage system and a preheating control method for preventing water and salt precipitation, which comprises a preheater arranged between the outlet end of a gas storage and the inlet end of a throttle valve. The preheater is arranged between the outlet end of the gas storage and the inlet end of the throttle valve, so that the high-pressure air extracted from the gas storage is first raised from the initial temperature T1 to the target temperature T2 before entering the throttle valve, thereby improving the ability of the high-pressure air to carry water and salt before throttling. At the same time, by controlling the air after preheating and throttling to satisfy M2>M3>=M1 and N2>N3>=N1, the maximum water content and the maximum salt content of the air after throttling are still greater than or equal to the actual water content and the actual salt content of the air extracted from the gas storage, thereby avoiding the water and salt precipitation of the high-pressure air during the throttling process.

Description

Technical Field

[0001] This invention relates to the field of air energy storage technology, and in particular to a compressed air energy storage system and preheating control method for preventing water and salt precipitation. Background Technology

[0002] Advanced adiabatic compressed air energy storage technology is a large-scale energy storage technology with promising application prospects. This technology typically uses electricity to drive a compressor unit to compress air during off-peak electricity demand periods, and the compressed air is stored in an air storage tank. During peak electricity demand periods, the high-pressure air in the storage tank is released, depressurized, and expanded to generate electricity. To improve system efficiency, the heat generated during compression is generally stored in a heat accumulator and storage tank, and during the energy release phase, a regenerator heats the high-pressure air before it is used by the expander unit. Adopting this structure reduces the need for external fuel reheating, thereby improving the overall energy utilization efficiency of the system.

[0003] In practical applications, salt caverns are commonly used for gas storage. Because salt caverns often retain some moisture and salt, the high-pressure air extracted from the gas storage facility may carry water vapor and salt into subsequent energy release processes. When the high-pressure air is depressurized through a throttling valve, its pressure and temperature decrease simultaneously, making it easier for the moisture and salt carried in the air to reach the precipitation conditions, resulting in water and salt precipitation. Especially at the throttling valve and its downstream pipelines, the precipitated liquid water or solid salt can easily cause blockages in the valve core, valve seat, and connecting pipes, not only affecting the continuous and stable operation of the system but also increasing maintenance frequency and operating costs.

[0004] Therefore, how to effectively avoid water and salt precipitation problems during the throttling process is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In this section, as well as in the abstract and title of this application, some simplifications or omissions may be made to avoid obscuring the purpose of this section, the abstract, and the title of this application, and such simplifications or omissions shall not be used to limit the scope of the invention.

[0006] To address the shortcomings of existing technologies, one objective of this invention is to provide a compressed air energy storage system that prevents water and salt precipitation.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a compressed air energy storage system for preventing water and salt precipitation, comprising a preheater disposed between the outlet end of the gas storage tank and the inlet end of a throttling valve; the initial temperature of the high-pressure air extracted from the gas storage tank is T1, and the initial pressure is P1, the actual water content corresponding to the initial temperature T1 and the initial pressure P1 is M1, and the actual salt content is N1; the high-pressure air is heated to a target temperature T2 by the preheater and then enters the throttling valve, the maximum water content corresponding to the target temperature T2 and the initial pressure P1 is M2, and the maximum salt content is N2; the throttling temperature of the high-pressure air after throttling by the throttling valve is T3, and the throttling pressure is P2, the maximum water content corresponding to the throttling temperature T3 and the throttling pressure P2 is M3, and the maximum salt content is N3; wherein, M2>M3≥M1, N2>N3≥N1.

[0008] As a preferred embodiment of the compressed air energy storage system for preventing water and salt precipitation according to the present invention, it further includes an expander unit, wherein the expander unit has a first-stage expander and a second-stage expander connected by pipelines, the high-temperature side inlet end of the preheater is connected to the outlet end of the second-stage expander, and the high-temperature side outlet end of the preheater is connected to the inlet end of the first-stage expander through the throttle valve.

[0009] As a preferred embodiment of the compressed air energy storage system for preventing water and salt precipitation according to the present invention, wherein: the outlet gas of the second-stage expander exchanges heat with the preheater to heat the high-pressure air extracted from the gas storage tank to a temperature not lower than the target temperature T2.

[0010] As a preferred embodiment of the compressed air energy storage system for preventing water and salt precipitation according to the present invention, it further includes: multiple regenerators disposed at the inlet end of the expander unit; wherein the high-temperature side outlet ends of the first regenerator and the second regenerator are respectively connected to the inlet ends of the first-stage expander and the second-stage expander, the low-temperature side inlet end of the first regenerator is connected to the high-temperature side outlet end of the preheater, and the low-temperature side inlet end of the second regenerator is connected to the outlet end of the first-stage expander.

[0011] As a preferred embodiment of the compressed air energy storage system for preventing water and salt precipitation according to the present invention, it further includes: a high-temperature heat storage tank, which is connected to the high-temperature inlet end of the first regenerator and the second regenerator; and a low-temperature heat storage tank, wherein the low-temperature outlet end of the first regenerator and the second regenerator is connected to the inlet end of the low-temperature heat storage tank.

[0012] As a preferred embodiment of the compressed air energy storage system for preventing water and salt precipitation according to the present invention, it further includes a multi-stage compression heat exchange unit, wherein the multi-stage compression heat exchange unit includes a multi-stage compressor connected sequentially along the compression direction and a plurality of heat accumulators respectively disposed at the outlet end of the multi-stage compressor; wherein the high-temperature side of the plurality of heat accumulators is connected to a high-temperature heat storage tank, and the low-temperature side of the plurality of heat accumulators is connected to a low-temperature heat storage tank.

[0013] As a preferred embodiment of the compressed air energy storage system for preventing water and salt precipitation according to the present invention, wherein: a first drive pump is provided at the outlet end of the high-temperature heat storage tank, and a second drive pump is provided at the outlet end of the low-temperature heat storage tank.

[0014] To address the shortcomings of existing technologies, another objective of this invention is to provide a preheating control method to prevent water and salt precipitation.

[0015] The present invention adopts the following technical solution: a preheating control method for preventing water and salt precipitation, comprising the following steps: preheating high-pressure air extracted from a gas storage tank into a preheater, raising the high-pressure air from an initial temperature T1 to a target temperature T2, wherein the initial pressure of the high-pressure air is P1; throttling the preheated high-pressure air into a throttling valve to obtain throttled air, wherein the temperature of the throttled air is the throttling temperature T3 and the pressure is the throttling pressure P2; wherein the actual water content corresponding to the initial temperature T1 and initial pressure P1 is M1 and the actual salt content is N1, the maximum water content corresponding to the target temperature T2 and initial pressure P1 is M2 and the maximum salt content is N2, and the maximum water content corresponding to the throttling temperature T3 and throttling pressure P2 is M3 and the maximum salt content is N3, and M2 > M3 ≥ M1, N2 > N3 ≥ N1.

[0016] As a preferred embodiment of the preheating control method for preventing water and salt precipitation according to the present invention, the method for obtaining the maximum water content M2 and maximum salt content N2 corresponding to the target temperature T2, and the maximum water content M3 and maximum salt content N3 corresponding to the throttling temperature T3 and throttling pressure P2 includes: establishing a simulation model including a solid salt stream SALT, a water stream H2O, a mixer MIX, a gas-liquid separator SP, and an air stream AIR; mixing the solid salt stream SALT and the water stream H2O in the mixer MIX to obtain a mixed liquid stream SOLU; introducing the mixed liquid stream SOLU into the gas-liquid separator SP, and introducing the air stream AIR into the gas-liquid separator SP for gas-liquid separation; setting the temperature and pressure parameters of the gas phase stream GAS output by the gas-liquid separator SP, obtaining the corresponding composition parameters, and substituting the composition parameters into the maximum water content calculation formula and the maximum salt content calculation formula to obtain the maximum water content and maximum salt content under different temperature and pressure conditions.

[0017] As a preferred embodiment of the preheating control method for preventing water and salt precipitation according to the present invention, wherein: based on the maximum water content and maximum salt content under different temperature and pressure conditions, a set of curves H showing the relationship between the maximum water content and pressure at different temperatures and a set of curves L showing the relationship between the maximum water content and pressure at different temperatures are obtained; the actual water content M1 and actual salt content N1 of the high-pressure air extracted from the gas storage tank are used as the benchmark values ​​for water precipitation and salt precipitation, respectively; based on the temperature parameters corresponding to the positions after preheating, after throttling, and at each process position during expansion, the values ​​in the set of curves H and L are used to determine the relationship between the maximum water content and pressure at different temperatures and pressure conditions; The target curve at the corresponding temperature is determined from the relationship curve group L, and the maximum water content and maximum salt content at each process position are determined in combination with the corresponding pressure parameters. When the maximum water content at each process position is greater than M1 and the maximum salt content at each process position is greater than N1, it is determined that no water or salt will be separated during the preheating, throttling and subsequent expansion of the high-pressure air. Based on the relationship curve group H and the relationship curve group L, the minimum throttling temperature T3 that simultaneously satisfies M3≥M1 and N3≥N1 at the throttling pressure P2 is determined, and the target temperature T2 after preheating is deduced accordingly.

[0018] The beneficial effects of this invention are as follows: By installing a preheater between the outlet end of the gas storage tank and the inlet end of the throttling valve, the high-pressure air extracted from the gas storage tank is raised from an initial temperature T1 to a target temperature T2 before entering the throttling valve, thereby improving the ability of the high-pressure air to carry moisture and salt before throttling. At the same time, by controlling the air after preheating and throttling to satisfy M2>M3≥M1 and N2>N3≥N1, the maximum water content and maximum salt content of the air after throttling are still greater than or equal to the actual water content and actual salt content of the air extracted from the gas storage tank. This avoids water and salt precipitation during the throttling process of the high-pressure air, reduces the risk of blockage of the throttling valve and subsequent pipelines due to the accumulation of precipitates, improves the stability, safety and reliability of the compressed air energy storage system, and helps to extend the equipment maintenance cycle and reduce operation and maintenance costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the connection of the preheater of the present invention.

[0021] Figure 2 This is a schematic diagram of the overall structure of the compressed air energy storage system for preventing water and salt precipitation according to the present invention.

[0022] Figure 3 This is a schematic diagram of the simulation model of the present invention.

[0023] Figure 4 This is a graph showing the relationship between the maximum water content at different temperatures and pressure according to the present invention.

[0024] Figure 5 This is a graph showing the relationship between the maximum salt content at different temperatures and pressure according to the present invention.

[0025] Figure 6 This is a diagram illustrating the water separation prevention verification of the present invention at various process locations.

[0026] Figure 7 This is a verification diagram of the salt precipitation prevention at various process locations of the present invention.

[0027] Figure 8 This is a verification diagram of the water separation prevention during the energy release process of this invention.

[0028] Figure 9 This is a verification diagram of the salt precipitation prevention during the energy release process of this invention.

[0029] In the diagram: 100 - Preheater; 200 - Gas storage tank; 300 - Throttling valve; 400 - Expander unit; 401 - First-stage expander; 402 - Second-stage expander; 500 - Regenerator; 501 - First regenerator; 502 - Second regenerator; 600 - High-temperature heat storage tank; 601 - First drive pump; 700 - Low-temperature heat storage tank; 701 - Second drive pump; 800 - Multi-stage compression heat exchange unit; 801 - Multi-stage compressor; 802 - Heat accumulator; SALT - Solid salt stream; H2O - Water stream; MIX - Mixer; SOLU - Mixed liquid stream; SP - Gas-liquid separator; AIR - Air stream; GAS - Gas phase stream; LIQ - Liquid phase stream; a1 - Actual moisture content of air extracted from the gas storage tank; b1 - Maximum moisture content of air after throttling; c1 - Maximum moisture content of air at the outlet of the first-stage expander; d1 - Maximum moisture content of air at the outlet of the second-stage expander; a2 - Actual salinity of air extracted from the gas storage tank; b2 - Maximum salinity of air after throttling; c2 - Maximum salinity of air at the outlet of the first-stage expander; d2 - Maximum salinity of air at the outlet of the second-stage expander; A - Curve showing the change in actual air content before preheating; B - Curve showing the change in maximum air content after throttling; H - Set of curves showing the relationship between maximum moisture content and maximum salinity; L - Set of curves showing the relationship between maximum salinity and maximum salinity. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0031] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0032] In this invention, "maximum water content" and "maximum salinity" refer to the maximum amount of water and salt that air can carry under corresponding temperature and pressure conditions; "actual water content" and "actual salinity" refer to the actual amount of water and salt carried by the high-pressure air extracted from the gas storage tank when it enters the subsequent process. For compressed air energy storage systems using salt caverns as gas storage tanks, residual water and salt in the salt caverns are unavoidable. Therefore, the high-pressure air extracted from the gas storage tank carries the risk of water and salt precipitation during energy release. This invention does not simply pursue an increase in air temperature before throttling, but rather establishes a correspondence between temperature, pressure, and maximum water and salt content to control the air after preheating and throttling to be in a safe region where water and salt precipitation does not occur, thereby solving the problem of blockage of the throttling valve and subsequent pipelines at the mechanistic level.

[0033] Example 1, referring to Figure 1 This embodiment provides a compressed air energy storage system to prevent water and salt precipitation, including a preheater 100, an air storage chamber 200, and a throttling valve 300. The preheater 100 is located between the outlet end of the air storage chamber 200 and the inlet end of the throttling valve 300. The air storage chamber 200 is preferably a salt cavern air storage chamber, but it can also be an underground cavern, artificial storage chamber, or other air storage device with similar high-pressure air storage functions and a risk of moisture and salt entrainment. The preheater 100 can be a shell-and-tube heat exchanger, plate heat exchanger, double-tube heat exchanger, or other heat exchange equipment suitable for high-pressure air heat exchange, as long as it can preheat the high-pressure air before it enters the throttling valve 300. The throttling valve 300 can be a regulating valve, pressure reducing valve, or other valve components capable of throttling and pressure reduction.

[0034] Specifically, the high-pressure air extracted from the gas storage tank 200 has an initial temperature T1 and an initial pressure P1, corresponding to an actual water content M1 and an actual salinity N1. After being heated to a target temperature T2 by the preheater 100, the high-pressure air enters the throttling valve 300. Under the conditions corresponding to the target temperature T2 and the initial pressure P1, the maximum water content of the air is M2, and the maximum salinity is N2. After being throttled by the throttling valve 300, the high-pressure air's temperature drops to T3, and its pressure drops to P2. Under the conditions corresponding to the throttling temperature T3 and the throttling pressure P2, the maximum water content of the air is M3, and the maximum salinity is N3.

[0035] This embodiment requires that M2 > M3 ≥ M1 and N2 > N3 ≥ N1 be satisfied simultaneously. The first set of inequalities indicates that the preheated air has an enhanced capacity to carry moisture and salt before entering the throttling valve 300, thus providing a safety margin for the temperature and pressure drops caused by subsequent throttling. Furthermore, the maximum water content M3 and maximum salt content N3 after throttling are still greater than or equal to the actual water content M1 and actual salt content N1, respectively. This means that even if the air experiences a certain degree of temperature and pressure drop after throttling, its state has not yet entered the water or salt precipitation region. Although the air has undergone throttling, its capacity to hold moisture and salt is still greater than its actual carrying capacity; therefore, liquid water and solid salt will not precipitate inside the throttling valve 300 or in its subsequent pipelines.

[0036] In this invention, when M3=M1, it indicates that the maximum moisture content of the air after throttling and the actual moisture content of the air extracted from the gas storage are in a critical equilibrium state; under ideal calculation conditions or stable operating conditions, the moisture in the air has not exceeded its carrying capacity limit, therefore no water precipitation occurs. When N3=N1, it indicates that the maximum salt content of the air after throttling and the actual salt content of the air extracted from the gas storage are in a critical equilibrium state; under ideal calculation conditions or stable operating conditions, the salt content in the air has not exceeded its carrying capacity limit, therefore no salt precipitation occurs. Preferably, to improve the system's tolerance to operating condition fluctuations, measurement errors, and model errors, in engineering implementation, M3>M1 and N3>N1 can be set aside to reserve a safety margin for preventing water and salt precipitation.

[0037] This embodiment treats "avoiding water and salt precipitation" as an independent control objective and moves this objective forward to be achieved before the throttling valve 300. This prevents the throttling point from becoming a crystallization or condensation point from the outset. Especially in salt cavern gas storage scenarios, since the air extracted from the gas storage tank 200 is usually not ideally pure air, but rather a complex gas that may contain some water vapor and salt, simply adding drainage, filtration, purging, or unblocking devices after the throttling valve 300 only provides passive handling after precipitation has already occurred. This embodiment uses a preheater 100 to ensure that the high-pressure air has sufficient thermodynamic margin before entering the throttling valve 300.

[0038] In a preferred embodiment, the target temperature T2 is not a fixed single value, but a control parameter determined jointly based on the initial temperature T1 and initial pressure P1 of the air extracted from the gas storage tank 200, the target pressure P2 after throttling, and the actual carrying levels of moisture and salt in the air. For different energy release conditions, different energy release periods, or different seasonal environments, T1, P1, and even M1 and N1 may change; therefore, the target temperature T2 can be set as a dynamically adjustable value, as long as the aforementioned inequality relationship is satisfied after preheating and throttling.

[0039] In actual operation, the working process of this embodiment can be described as follows: During the energy release stage, the high-pressure air in the gas storage tank 200 first flows into the preheater 100, and after absorbing heat in the preheater 100, it rises from the initial temperature T1 to the target temperature T2; then, the preheated high-pressure air enters the throttle valve 300, and the pressure is reduced in the throttle valve 300 to obtain throttled air with a temperature of T3 and a pressure of P2; this throttled air can then be continuously transported to the expander, regenerator, reheater or other energy release equipment for work utilization.

[0040] In Comparative Example 1, the system does not have a preheater 100, and the high-pressure air extracted from the gas storage tank 200 directly enters the throttling valve 300. Although this scheme has a simple structure, under salt cavern gas extraction conditions, the air temperature drops rapidly after throttling. If M3 < M1 or N3 < N1, the air's capacity to hold moisture or salt is lower than its actual carrying capacity, directly leading to droplet condensation or salt precipitation inside the throttling valve 300. Therefore, Comparative Example 1 lacks the ability to actively adjust the state before throttling, making long-term stable operation difficult.

[0041] In Comparative Example 2, although heat exchange equipment was also installed to preheat the high-pressure air, the goal was only to "increase the temperature" without verifying the relationship between M2, M3, N2, N3 and M1, N1. When the preheating is insufficient, even though T2 is higher than T1, the maximum water content M3 and maximum salt content N3 after throttling may still be lower than the actual contents M1 and N1, thus water and salt precipitation will still occur.

[0042] In Comparative Example 3, the heat exchanger is located after the throttling valve 300, meaning throttling occurs before heating. While this approach improves the subsequent utilization of air after throttling, it cannot prevent water and salt precipitation from occurring at the moment of throttling. This is because precipitation often first occurs inside the throttling valve 300 or in a short section of pipe downstream. Once liquid water or solid salt has formed at this location, subsequent heating can only partially restore the gaseous state and cannot effectively remove the precipitates already attached to the valve core, valve seat, or local gaps.

[0043] Table 1 shows the comparative data of the comparative examples and the present invention under typical operating conditions.

[0044] The following example uses a typical operating point in the energy release process. The maximum water content is taken as... The maximum salt content is taken as .

[0045]

[0046] As shown in Table 1, under the same initial temperature and pressure of the extracted air from the gas storage tank, without a preheater, the maximum water content M3 and maximum salt content N3 of the high-pressure air after throttling are lower than the actual water content M1 and actual salt content N1 of the extracted air. Therefore, water and salt precipitation are likely to occur at the throttling valve and its subsequent pipelines. Even with a preheater, if the preheating is insufficient, the air state after throttling will still not satisfy M3≥M1 and N3≥N1, thus still posing a risk of precipitation. In contrast, this invention preheats the high-pressure air to the target temperature T2, ensuring that the preheated and throttled air satisfies M2>M3≥M1 and N2>N3≥N1. This demonstrates that the throttled air still has a carrying capacity higher than the actual carrying capacity, thereby preventing water and salt precipitation.

[0047] Table 2 shows the comparison data of each process point in this invention.

[0048]

[0049] As shown in Table 2, when the actual water content M1 and actual salinity N1 at the gas storage extraction point are used as the benchmark values, the maximum water content and maximum salinity at each key process point of this invention are all higher than these benchmark values. Specifically, the positions after throttling still satisfy M3 > M1 and N3 > N1, indicating that the throttling process does not trigger the precipitation of water and salt. Furthermore, during the subsequent expansion process, due to the increased temperature and pressure of the air after reheating and expansion, the maximum carrying capacity at each process point further increases, thus preventing water and salt precipitation.

[0050] Table 3 shows example data on the change in water content with energy release time.

[0051]

[0052] As shown in Table 3, throughout the energy release process, the maximum water content B1 of the air after throttling is consistently higher than the actual water content A1 of the air before preheating, indicating that the air after throttling still has sufficient water-carrying capacity and therefore no water separation occurs. As the energy release process progresses, both the actual water content of the air before preheating and the maximum water content of the air after throttling change to a certain extent, but they always maintain a positive difference, demonstrating that the present invention maintains its anti-water separation effect throughout the entire energy release time.

[0053] Table 4 shows example data on the change in salt content with energy release time.

[0054]

[0055] As shown in Table 4, throughout the entire energy release process, the maximum salt content B2 of the air after throttling was consistently higher than the actual salt content A2 of the air before preheating. This indicates that the air after throttling can still accommodate the salt carried in the extracted air, thus preventing salt precipitation. Although both A2 and B2 changed with the extension of the energy release time, B2 consistently remained higher than A2, demonstrating that the proposed solution can maintain the anti-salt precipitation effect throughout the entire energy release stage.

[0056] To verify the effectiveness of the present invention, the applicant further constructed Comparative Example 1, Comparative Example 2, and Example 1. In Comparative Example 1, no preheater was installed, and the high-pressure air was directly drawn from the gas storage tank into the throttling valve. In Comparative Example 2, although a preheater was installed, the target temperature after preheating was insufficient. In Example 1, the high-pressure air was preheated to the target temperature range satisfying M2 > M3 ≥ M1 and N2 > N3 ≥ N1. Simulation results show that in Comparative Example 1 and Comparative Example 2, at least M3 < M1 or N3 < N1 exists after throttling, thus easily leading to water and / or salt precipitation in the throttling valve and its subsequent pipelines. In Example 1, the air after preheating and throttling always satisfies the above inequality relationship, and the maximum water content and maximum salt content corresponding to each key process point are higher than the actual water content and actual salt content of the air drawn from the gas storage tank, thereby effectively avoiding the occurrence of water and salt precipitation.

[0057] Furthermore, to facilitate understanding of the intrinsic relationships between the parameters, a thermodynamic explanation can be provided as follows: Under the same pressure conditions, as the air temperature increases, the upper limit of the water and salt content that can remain in a gaseous state usually increases accordingly; however, when the air is depressurized through the throttling valve 300, its carrying capacity weakens accordingly due to the temperature drop accompanying the throttling process. Therefore, this invention does not consider "maximum water and salt content of the air after throttling as high as possible" in isolation, but rather uses the actual content M1 and N1 of the air extracted from the gas storage tank 200 as a comparison benchmark, and comprehensively judges the three states before preheating, after preheating, and after throttling. Only when the maximum content after throttling is still higher than the actual content can the risk of water and salt precipitation be fundamentally eliminated. In an exemplary engineering application, the control system can read the outlet temperature, pressure, and historical content data of the gas storage tank 200 before the energy release begins, and then quickly calculate the minimum required target temperature T2 in conjunction with the throttling target pressure P2. When the calculation results show that the existing waste heat is sufficient to bring the outlet of preheater 100 to the required temperature, the system directly enters the stable energy release phase; when the calculation results show that the waste heat is insufficient, the system can adjust the opening rate of throttle valve 300, reduce the single energy release load, or call other auxiliary heat sources for supplementary heating.

[0058] Example 2, refer to Figure 2This embodiment further includes an expander unit 400 based on embodiment 1. The expander unit 400 has a first-stage expander 401 and a second-stage expander 402 connected by pipelines. The high-temperature side inlet end of the preheater 100 is connected to the outlet end of the second-stage expander 402, and the high-temperature side outlet end of the preheater 100 is connected to the inlet end of the first-stage expander 401 through a throttle valve 300.

[0059] With this arrangement, the waste heat gas discharged from the second-stage expander 402 can be directly used as the hot-side heat source of the preheater 100, while the high-pressure air from the gas storage tank 200 flows through the preheater 100 as the cold-side working fluid. The advantage of this structure is that a clear thermal coupling relationship is formed between the preheater 100 and the expander unit 400. The outlet gas of the second-stage expander 402 usually still has a certain temperature level; if it is directly discharged, it will not only waste waste heat but also fail to serve the pre-throttling anti-segregation control. In this embodiment, the gas is introduced into the preheater 100, which can complete the pre-throttling preheating without the need for an additional independent heating furnace. The number of stages of the first-stage expander 401 and the second-stage expander 402 is not limited to the exact same equipment form; those skilled in the art can select radial flow, axial flow, or other suitable types of expanders based on pressure ratio distribution, speed requirements, and power rating.

[0060] Example 3, referring to Figure 2 Based on Example 2, this example further defines and explains the heat source conditions of the preheater 100. Specifically, the outlet gas of the second-stage expander 402 enters the high-temperature side of the preheater 100 and serves as the heat source for the preheater 100 to heat the high-pressure air extracted from the gas storage tank 200. To ensure that the high-pressure air reaches the target temperature T2 after preheating, the outlet gas temperature of the second-stage expander 402 should be higher than the target temperature T2 corresponding to the outlet air on the low-temperature side of the preheater 100, or at least, under the combined effect of heat exchange driving force, heat exchange area, and heat exchange efficiency, it should be sufficient to heat the high-pressure air to a temperature not lower than the target temperature T2 after passing through the preheater 100.

[0061] High-pressure air from the gas storage tank 200 enters through the low-temperature inlet of the preheater 100, where it exchanges heat with high-temperature gas from the outlet of the second-stage expander 402. After heat exchange, the temperature of the high-pressure air rises from the initial temperature T1 to the target temperature T2 before entering the throttling valve 300. Because the preheated high-pressure air has a higher temperature, its maximum water content M2 and maximum salt content N2 at the initial pressure P1 increase. This makes it easier for the throttled air to satisfy the relationships M2 > M3 ≥ M1 and N2 > N3 ≥ N1, thus preventing water and salt precipitation during the throttling process.

[0062] Therefore, in a preferred embodiment, when the outlet gas temperature of the second-stage expander 402 is insufficient to heat the high-pressure air to the target temperature T2, compensation can be made by increasing the outlet gas temperature of the second-stage expander 402 and / or adding an auxiliary heat source. Methods for increasing the outlet gas temperature of the second-stage expander 402 include, but are not limited to: adjusting the operating parameters of the second-stage expander 402, optimizing its inlet gas temperature, pressure, or flow rate, reducing the expansion ratio of the second-stage expander 402, or increasing the degree of heating of the air entering the second-stage expander 402 by the preheater. The auxiliary heat source can be located at the high-temperature side inlet or in the high-temperature side flow path of the preheater 100, and is used to heat the high-pressure air extracted from the gas storage tank 200 together with the outlet gas of the second-stage expander 402; this auxiliary heat source can be an electric heating device, a thermal oil heating device, a steam heating device, an additional waste heat gas heat source, or other available low-grade waste heat sources in the system.

[0063] In this embodiment, the minimum heating capacity required by the preheater 100 is preferably calculated based on the target temperature T2, and the minimum temperature condition required for the outlet gas of the second-stage expander 402 is determined accordingly. Specifically, when the outlet gas of the second-stage expander 402 is used as a heat source alone, the available heat generated by its outlet gas temperature, flow rate, and specific heat capacity should not be less than the heat exchange required to raise the high-pressure air extracted from the gas storage tank 200 from the initial temperature T1 to the target temperature T2; when the outlet gas of the second-stage expander 402 alone is insufficient to provide heat, an auxiliary heat source is used to supplement the difference in heat to ensure that the outlet air temperature on the low-temperature side of the preheater 100 stably reaches or exceeds the target temperature T2.

[0064] Example 4, refer to Figure 2 This embodiment adds a regenerator 500 to the above embodiment. Multiple regenerators 500 are provided at the inlet end of the expander unit 400. The high-temperature side outlet ends of the first regenerator 501 and the second regenerator 502 are respectively connected to the inlet ends of the first-stage expander 401 and the second-stage expander 402. The low-temperature side inlet end of the first regenerator 501 is connected to the high-temperature side outlet end of the preheater 100, and the low-temperature side inlet end of the second regenerator 502 is connected to the outlet end of the first-stage expander 401.

[0065] This structure forms a relatively complete energy release and heat exchange chain: the preheater 100 first uses the waste heat from the final stage expansion to preheat the high-pressure air before throttling to ensure throttling safety; then, the throttled air can absorb heat from the high-temperature heat storage medium through the first regenerator 501 before entering the first-stage expander 401, thereby improving its expansion and work capacity; the air discharged from the first-stage expander 401 is further heated by the second regenerator 502 before entering the second-stage expander 402 to continue doing work. Thus, the preheater 100 focuses on preventing water and salt precipitation during throttling, while the first regenerator 501 and the second regenerator 502 focus on restoring the enthalpy of the expansion medium and improving energy release efficiency. Although their functions are different, they are interconnected.

[0066] Example 5, refer to Figure 2 In this embodiment, a high-temperature heat storage tank 600 and a low-temperature heat storage tank 700 are further provided. The high-temperature heat storage tank 600 is connected to the high-temperature side inlet end of the first regenerator 501 and the second regenerator 502, and the low-temperature heat storage tank 700 is connected to the low-temperature side outlet end of the first regenerator 501 and the second regenerator 502.

[0067] The high-temperature heat storage tank 600 is used to store the high-temperature heat storage medium recovered during the compression stage, while the low-temperature heat storage tank 700 is used to collect the low-temperature heat storage medium after heat release during the energy release stage. Through the arrangement of the high-temperature heat storage tank 600 and the low-temperature heat storage tank 700, the system can realize the transfer and allocation of compression heat over time. That is, the heat generated by the compressor during the compression stage is stored in the high-temperature heat storage tank 600; during the energy release stage, this heat is released to the expanding working fluid via the first regenerator 501 and the second regenerator 502.

[0068] Example 6, refer to Figure 2 This embodiment, based on the aforementioned embodiments, further includes a multi-stage compression heat exchange unit 800. The multi-stage compression heat exchange unit 800 preferably includes a three-stage compressor and three heat accumulators. Specifically, the multi-stage compressor 801 includes a first-stage compressor, a second-stage compressor, and a third-stage compressor connected sequentially along the compression direction; the multiple heat accumulators 802 include a first heat accumulator, a second heat accumulator, and a third heat accumulator respectively disposed at the outlet end of the aforementioned three-stage compressor.

[0069] The airflow path is as follows: the outlet of the first-stage compressor is connected to the air-side inlet of the first heat accumulator; the air-side outlet of the first heat accumulator is connected to the inlet of the second-stage compressor; the outlet of the second-stage compressor is connected to the air-side inlet of the second heat accumulator; the air-side outlet of the second heat accumulator is connected to the inlet of the third-stage compressor; the outlet of the third-stage compressor is connected to the air-side inlet of the third heat accumulator; and the air-side outlet of the third heat accumulator is connected to the inlet of the gas storage tank 200. Thus, air is pressurized by the first-stage compressor, enters the first heat accumulator to release heat, and then enters the second-stage compressor; after being further pressurized by the second-stage compressor, it enters the second heat accumulator to release heat, and then enters the third-stage compressor; the high-pressure air compressed by the third-stage compressor enters the third heat accumulator to release heat, and finally enters the gas storage tank 200 for storage.

[0070] Regarding the flow path of the heat storage medium, the high-temperature sides of the first, second, and third heat accumulators are all connected to the high-temperature heat storage tank 600, and the low-temperature sides are all connected to the low-temperature heat storage tank 700. Specifically, the low-temperature heat storage medium from the low-temperature heat storage tank 700 enters the three heat accumulators respectively. After absorbing the heat of compression from the exhaust air of the corresponding compression stage in each heat accumulator, it is transformed into a high-temperature heat storage medium and then flows into the high-temperature heat storage tank 600 for storage. In other words, the three heat accumulators correspond to the outlet end of the three-stage compressor respectively, and together they form a heat recovery path from the low-temperature heat storage tank 700 to the high-temperature heat storage tank 600.

[0071] Example 7, referring to Figure 2 This embodiment further specifies that a first drive pump 601 is provided at the outlet end of the high-temperature thermal storage tank 600, and a second drive pump 701 is provided at the outlet end of the low-temperature thermal storage tank 700. The first drive pump 601 is used to drive the high-temperature thermal storage medium to flow to the first regenerator 501 and the second regenerator 502, and the second drive pump 701 is used to drive the low-temperature thermal storage medium to flow to each accumulator 802 to reabsorb the heat of compression. By setting the first drive pump 601 and the second drive pump 701, the circulation stability of the thermal storage medium during the charging and releasing stages can be improved, and the problem of insufficient flow caused by system resistance, pipeline length or equipment height difference can be reduced.

[0072] Preferably, the first drive pump 601 is located on the main pipeline between the high-temperature heat storage tank 600 and the first regenerator 501 and the second regenerator 502. After being pressurized by the first drive pump 601, the high-temperature heat storage medium in the high-temperature heat storage tank 600 is transported to the high-temperature side inlet end of the first regenerator 501 and the second regenerator 502. In the first regenerator 501 and the second regenerator 502, the heat is released to the air before entering the expander unit 400. The heat-released heat storage medium is transformed into a low-temperature heat storage medium and flows back to the low-temperature heat storage tank 700 for storage through the corresponding pipeline.

[0073] The second drive pump 701 is preferably located on the main pipeline between the low-temperature heat storage tank 700 and the multi-stage compression heat exchange unit 800. After being pressurized by the second drive pump 701, the low-temperature heat storage medium in the low-temperature heat storage tank 700 is transported to the low-temperature side of the first, second, and third heat accumulators. After absorbing the heat of compression from the air discharged from the corresponding compression stage in each heat accumulator, it is transformed into a high-temperature heat storage medium and then flows back to the high-temperature heat storage tank 600 for storage through the corresponding pipeline.

[0074] Example 8, referring to Figure 1 This embodiment provides a preheating control method to prevent water and salt precipitation. The method includes the following steps: First, high-pressure air extracted from the gas storage tank 200 is introduced into the preheater 100 for preheating, so that the high-pressure air rises from the initial temperature T1 to the target temperature T2, and the initial pressure is P1; Second, the preheated high-pressure air is introduced into the throttling valve 300 for throttling, resulting in throttled air with a temperature of T3 and a pressure of P2; wherein, the actual water content corresponding to the initial temperature T1 and the initial pressure P1 is M1, and the actual salt content is N1; the maximum water content corresponding to the target temperature T2 and the initial pressure P1 is M2, and the maximum salt content is N2; the maximum water content corresponding to the throttling temperature T3 and the throttling pressure P2 is M3, and the maximum salt content is N3, and M2 > M3 ≥ M1, N2 > N3 ≥ N1.

[0075] In a preferred embodiment, the method can calculate the target temperature T2 once before the start of each energy release cycle, or it can be continuously updated during the energy release process. Especially in the later stages of energy release, when the pressure in the gas storage tank 200 gradually decreases and the air state continues to change, the dynamic update method is more conducive to ensuring that M3 is always greater than or equal to M1 and N3 is always greater than or equal to N1.

[0076] Example 9, referring to Figure 3 This embodiment further illustrates the specific methods for obtaining the maximum water content M2 and maximum salinity N2 corresponding to the target temperature T2, as well as the maximum water content M3 and maximum salinity N3 corresponding to the throttling temperature T3 and throttling pressure P2. This method preferably utilizes a gas-liquid equilibrium simulation model established using AspenPlus. AspenPlus is a process systems engineering simulation software used for gas-liquid equilibrium calculations of salt-water-air systems.

[0077] Specifically, a simulation model was built in AspenPlus, comprising a solid salt stream (SALT), a water stream (H2O), a mixer (MIX), a gas-liquid separator (SP), and an air stream (AIR). The solid salt stream (SALT) and the water stream (H2O) are mixed in the mixer (MIX) to form a mixed liquid stream (SOLU). The mixed liquid stream (SOLU) enters the gas-liquid separator (SP), while air (AIR) is simultaneously introduced into the SP, allowing the air and saline system to undergo gas-liquid equilibrium calculations within the SP. The gas-liquid separator (SP) outputs a gaseous stream (GAS) and a liquid stream (LIQ).

[0078] The gaseous flow gas (GAS) characterizes the state of water vapor and salt that air can carry under corresponding temperature and pressure conditions. Therefore, in this embodiment, the calculation parameters for the maximum water content and the maximum salt content are preferably obtained from the gaseous flow gas (GAS).

[0079] In a preferred embodiment, parameter scanning or sensitivity analysis can be used to set the temperature and pressure corresponding to the gaseous gas stream (GAS) group by group. For example, the temperature can be set to several groups of conditions such as 20°C, 30°C, 40°C, 50°C, and 60°C, and the pressure can be set to several groups of conditions such as 1 bar, 2 bar, 4 bar, 8 bar, 16 bar, 32 bar, 64 bar, and 128 bar. For each temperature and pressure combination, AspenPlus outputs the corresponding gaseous gas stream GAS data. This allows for the acquisition of the GAS stream composition and physical properties under different temperature and pressure conditions, providing fundamental data for subsequent calculations of maximum water content and maximum salinity.

[0080] In this embodiment, the maximum water content per kilogram of air can be calculated using the following formula: , In the formula, It indicates the water content per kilogram of air, with the unit being kg / (kg·Air); This represents the molar amount of water in the gas phase, expressed in mol. This represents the molar mass of water, expressed in kg / mol. The total mass of air is expressed in kg.

[0081] Under a set temperature and pressure condition, AspenPlus only needs to read the molar amount of water in the gaseous gas stream GAS corresponding to that condition. and total air quality This allows us to calculate the maximum water content per kilogram of air under that operating condition.

[0082] The maximum salt content per kilogram of air can be calculated using the following formula: , In the formula, This indicates the salt content per kilogram of air, expressed in kg / (kg·Air). The mole fraction of dissolved salt; The molar density of water vapor, in units of ; Air density, in units of ; The value is the molar mass of the salt, expressed in kg / mol.

[0083] Under a specific temperature and pressure condition, AspenPlus only needs to read the composition and physical properties of the gaseous gas stream (GAS) related to salt content calculation, such as the mole fraction of dissolved salt. Molar density of water vapor and air mass density This allows us to calculate the maximum salt content per kilogram of air under that operating condition.

[0084] Therefore, the process of obtaining the maximum water content and maximum salinity in this embodiment can be summarized as follows: First, set the temperature and pressure conditions for the gas-liquid separator SP in AspenPlus.

[0085] Secondly, the gas phase stream GAS corresponding to this operating condition is output by the gas-liquid separator SP.

[0086] Next, parameters such as the molar amount of water in the gas phase, the total mass of air, the molar fraction of dissolved salt, the molar density of water vapor, and the mass density of air were read from the gaseous gas stream GAS.

[0087] Finally, by substituting the above parameters into the formulas for calculating maximum water content and maximum salinity, the maximum water content and maximum salinity under the given temperature and pressure conditions are obtained.

[0088] Example 10, referring to Figure 4 and Figure 5 This embodiment further illustrates how to use the maximum water content and maximum salt content data under different temperature and pressure conditions to determine the risk of water and salt precipitation in the system during preheating, throttling and subsequent expansion processes, and to reverse-calculate the target temperature T2 that the preheater 100 needs to achieve.

[0089] Specifically, based on the maximum water content and maximum salinity data obtained in Example 9 under different temperature and pressure conditions, sets of curves H and L showing the relationship between maximum water content and pressure at different temperatures were plotted. Each curve in set H corresponds to a specific temperature condition, representing the relationship between maximum water content and pressure at that temperature; similarly, each curve in set L corresponds to a specific temperature condition, representing the relationship between maximum salinity and pressure at that temperature. In this embodiment, the sets of curves are not single curves, but rather graphically represent the relationship between temperature, pressure, and maximum water content / maximum salinity in a two-dimensional coordinate system, with pressure P as the abscissa, maximum water content or maximum salinity as the ordinate, and different curves corresponding to different temperatures.

[0090] in, Figure 4 The graph shows the relationship between maximum water content and pressure at different temperatures, with the horizontal axis representing pressure P and the vertical axis representing maximum water content. Figure 5 This graph shows the relationship between maximum salinity and pressure at different temperatures. The horizontal axis represents pressure P, and the vertical axis represents maximum salinity. Different curves in the graph correspond to different temperature conditions. Figure 4 and Figure 5 None of them are single change curves, but rather a group of curves composed of relationship curves under multiple temperature conditions. Through... Figure 4 and Figure 5 By selecting the target curve at the corresponding temperature and combining it with the target pressure parameters, the maximum water content and maximum salt content of the air at the corresponding state point can be determined, thereby judging whether there is a risk of water and salt precipitation at that state point.

[0091] in, Figure 4 The curves at 20℃, 30℃, 40℃, 50℃, and 60℃ represent the relationship between maximum water content and pressure at the corresponding temperature conditions. P represents pressure.

[0092] in, Figure 5 The curves at 20℃, 30℃, 40℃, 50℃, and 60℃ represent the relationship between the maximum salinity and pressure at the corresponding temperatures. P represents pressure.

[0093] In this embodiment, the actual water content M1 and actual salt content N1 of the high-pressure air extracted from the gas storage tank 200 are used as the benchmark values ​​for water precipitation and salt precipitation, respectively. For the locations after preheating, after throttling, and during each process step of expansion, the temperature parameters corresponding to these locations can be determined first. Then, a target curve corresponding to the temperature parameter can be selected from the relationship curve group H and the relationship curve group L. Subsequently, combined with the pressure parameters corresponding to these locations, the maximum water content and maximum salt content at that pressure can be found on the target curve. Thus, the maximum water carrying capacity and maximum salt carrying capacity of each process location under the corresponding temperature and pressure conditions can be obtained.

[0094] Furthermore, when the maximum water content at each process location is greater than the actual water content M1, and the maximum salt content at each process location is greater than the actual salt content N1, it indicates that the high-pressure air has a carrying capacity higher than the actual amount carried at each of the above process locations, and therefore water and salt precipitation will not occur. Conversely, if the maximum water content at a certain process location is not greater than M1, or the corresponding maximum salt content is not greater than N1, it indicates that there is a risk of water or salt precipitation at that location.

[0095] In a preferred embodiment, the focus can be on determining the position after throttling. Specifically, under the condition that the throttling pressure P2 is determined, the maximum water content and maximum salinity at different temperatures can be retrieved from the relationship curve set H and the relationship curve set L, respectively, and the minimum throttling temperature T3 that simultaneously satisfies M3≥M1 and N3≥N1 can be determined. The minimum throttling temperature required to prevent water separation is the minimum temperature corresponding to the maximum water content being greater than or equal to M1, and the minimum throttling temperature required to prevent salt separation is the minimum temperature corresponding to the maximum salinity being greater than or equal to N1. The higher of these two values ​​can be taken as the minimum throttling temperature T3 required to simultaneously avoid water separation and salt separation.

[0096] After determining the minimum throttling temperature T3, the target preheated temperature T2 can be deduced by combining the thermodynamic state relationship of the air before and after the throttling process. Since the temperature of the high-pressure air after throttling through the throttling valve 300 is determined by both the pre-throttling state and the throttling pressure P2, given the initial pressure P1, the throttling pressure P2, and the minimum throttling temperature T3 required to prevent water and salt precipitation, the minimum preheated temperature that the high-pressure air needs to reach before entering the throttling valve 300, i.e., the target temperature T2, can be deduced based on the thermodynamic relationship corresponding to the throttling process. Therefore, the requirement to prevent water and salt precipitation after throttling can be transformed into a control requirement regarding the minimum preheated temperature to which the air should be preheated before throttling.

[0097] Example 11, referring to Figure 6 and Figure 7This embodiment verifies the feasibility of the present invention in a practical system. Specifically, after constructing the compressed air energy storage system according to the present invention, actual operating data from multiple key process locations are selected during the system's energy release process. Combined with the temperature and pressure parameters corresponding to each process location, the maximum water content and maximum salinity are determined. Figure 6 and Figure 7 Each point in the data is based on the actual operating conditions of the system, rather than being a purely theoretical derivation. Therefore, it can be used to directly verify the effectiveness of the present invention under real-world conditions.

[0098] in, Figure 6 This is used to represent the comparison between the maximum and actual moisture content at each key process location. Preferably, a1 represents the actual moisture content of the air extracted from the gas storage tank 200, serving as the benchmark value for water separation judgment; b1 represents the maximum moisture content corresponding to the location after throttling; c1 represents the maximum moisture content corresponding to the outlet location of the first-stage expander 401; and d1 represents the maximum moisture content corresponding to the outlet location of the second-stage expander 402. Since... Figure 6 b1, c1, and d1 are all greater than a1, indicating that the maximum water-carrying capacity of the air at each key process location is higher than the actual water content of the air extracted from the gas storage tank after throttling and during subsequent expansion. Therefore, the water actually carried in the air will not be released at the above locations, thus demonstrating that the present invention is feasible in preventing water separation.

[0099] Figure 7 This is used to represent the comparison between the maximum and actual salinity at each key process location. Preferably, a2 represents the actual salinity of the air extracted from the gas storage tank 200, serving as the benchmark value for salt precipitation judgment; b2 represents the maximum salinity at the location after throttling; c2 represents the maximum salinity at the outlet location of the first-stage expander 401; and d2 represents the maximum salinity at the outlet location of the second-stage expander 402. Since... Figure 7 b2, c2, and d2 are all greater than a2, indicating that the maximum salt-carrying capacity of the air at each key process location is higher than the actual salt content of the air extracted from the gas storage tank after throttling and during subsequent expansion. Therefore, the salt actually carried in the air will not precipitate at the above locations, thus demonstrating that the present invention is also feasible in preventing salt precipitation.

[0100] Therefore, this embodiment passes Figure 6 and Figure 7 The actual data points in the system were used to verify the process point of the present invention. It was found that after the present invention was completed, the key positions in the system after throttling and in the subsequent expansion process all met the requirements of "maximum water content greater than actual water content and maximum salt content greater than actual salt content". Therefore, the present invention can effectively avoid the occurrence of water and salt precipitation in actual operation.

[0101] Example 12, refer to Figure 8 and Figure 9 This embodiment verifies the continued feasibility of the present invention's solution throughout the entire energy release time range. Unlike Embodiment 11, which focuses on process point verification at critical process locations, this embodiment mainly examines whether the system continues to meet the requirements for preventing water and salt precipitation as the energy release time changes after the system is constructed according to the present invention.

[0102] in, Figure 8 This is used to represent the comparison of air moisture content during energy release. Preferably, curve A represents the change in actual air moisture content before preheating with energy release time, and curve B represents the change in maximum air moisture content after throttling with energy release time. Because throughout the entire energy release process... Figure 8 Curve B in the figure is always above curve A, meaning that the maximum moisture content of the air after throttling is always greater than the actual moisture content of the air before preheating. This indicates that throughout the entire energy release time, the moisture-carrying capacity of the air after throttling is always higher than the actual moisture content carried by the air, and the moisture in the air will not be released. This shows that the present invention can continuously prevent water release throughout the entire energy release stage.

[0103] Figure 9 This is used to represent the comparative relationship of air salinity during the energy release process. Preferably, curve A represents the change curve of the actual salinity of the air before preheating with the energy release time, and curve B represents the change curve of the maximum salinity of the air after throttling with the energy release time. Since throughout the entire energy release process... Figure 9 Curve B in the figure is always above curve A, meaning that the maximum salt content of the air after throttling is always greater than the actual salt content of the air before preheating. This indicates that the capacity of the air after throttling to hold salt is always higher than the actual salt content carried by the air throughout the entire energy release time, and the salt in the air will not precipitate. This shows that the present invention can continuously prevent salt precipitation throughout the entire energy release stage.

[0104] Therefore, this embodiment uses Figure 8 and Figure 9 The overall comparison between curves A and B verifies the entire energy release process of the present invention. Since the maximum water content and maximum salinity corresponding to curve B are consistently greater than the actual water content and actual salinity corresponding to curve A throughout the entire energy release process, this indicates that the present invention is feasible not only at a specific moment or process point, but also exhibits stable anti-water and anti-salinity effects throughout the entire energy release time range. This further verifies the reliability and continuous effectiveness of the present invention in actual operation.

[0105] Finally, it should be noted that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A compressed air energy storage system for preventing water and salt precipitation, characterized in that: include, A preheater (100) is located between the outlet end of the gas storage tank (200) and the inlet end of the throttle valve (300); The initial temperature of the high-pressure air extracted from the gas storage tank (200) is T1, and the initial pressure is P1. The actual water content corresponding to the initial temperature T1 and the initial pressure P1 is M1, and the actual salt content is N1. The high-pressure air is heated to the target temperature T2 by the preheater (100) and then enters the throttle valve (300). The maximum water content corresponding to the target temperature T2 and the initial pressure P1 is M2 and the maximum salt content is N2. The throttling temperature of the high-pressure air after being throttled by the throttling valve (300) is T3 and the throttling pressure is P2. The maximum water content corresponding to the throttling temperature T3 and the throttling pressure P2 is M3 and the maximum salt content is N3. Among them, M2>M3≥M1, N2>N3≥N1.

2. The compressed air energy storage system for preventing water and salt precipitation as described in claim 1, characterized in that: It also includes an expander unit (400). The expander unit (400) has a first-stage expander (401) and a second-stage expander (402) connected by pipelines. The high-temperature side inlet end of the preheater (100) is connected to the outlet end of the second-stage expander (402). The high-temperature side outlet end of the preheater (100) is connected to the inlet end of the first-stage expander (401) through the throttle valve (300).

3. The compressed air energy storage system for preventing water and salt precipitation as described in claim 2, characterized in that: The outlet gas of the second-stage expander (402) exchanges heat with the preheater (100) to heat the high-pressure air extracted from the gas storage tank (200) to a temperature not lower than the target temperature T2.

4. The compressed air energy storage system for preventing water and salt precipitation as described in claim 2 or 3, characterized in that: It also includes a regenerator (500). Multiple regenerators (500) are provided at the inlet end of the expander unit (400); The high-temperature side outlets of the first regenerator (501) and the second regenerator (502) are connected to the inlet ends of the first-stage expander (401) and the second-stage expander (402), respectively. The low-temperature side inlet of the first regenerator (501) is connected to the high-temperature side outlet of the preheater (100), and the low-temperature side inlet of the second regenerator (502) is connected to the outlet end of the first-stage expander (401).

5. The compressed air energy storage system for preventing water and salt precipitation as described in claim 4, characterized in that: It also includes, A high-temperature heat storage tank (600) is connected to the high-temperature side inlet end of the first regenerator (501) and the second regenerator (502); The low-temperature heat storage tank (700) has its low-temperature side outlet end of the first regenerator (501) and the second regenerator (502) connected to the inlet end of the low-temperature heat storage tank (700).

6. The compressed air energy storage system for preventing water and salt precipitation as described in claim 5, characterized in that: It also includes, A multi-stage compression heat exchange unit (800) includes a multi-stage compressor (801) connected sequentially along the compression direction and a plurality of heat accumulators (802) respectively disposed at the outlet end of the multi-stage compressor (801). The high-temperature side of the plurality of heat accumulators (802) is connected to the high-temperature heat storage tank (600), and the low-temperature side of the plurality of heat accumulators (802) is connected to the low-temperature heat storage tank (700).

7. The compressed air energy storage system for preventing water and salt precipitation as described in claim 5 or 6, characterized in that: The outlet end of the high-temperature thermal storage tank (600) is provided with a first drive pump (601), and the outlet end of the low-temperature thermal storage tank (700) is provided with a second drive pump (701).

8. A preheating control method for preventing water and salt precipitation, characterized in that: Includes the following steps: High-pressure air extracted from the gas storage tank (200) is introduced into the preheater (100) for preheating, so that the high-pressure air is raised from the initial temperature T1 to the target temperature T2, and the initial pressure of the high-pressure air is P1; Preheated high-pressure air is introduced into a throttle valve (300) for throttling to obtain throttled air. The temperature of the throttled air is the throttling temperature T3, and the pressure is the throttling pressure P2. Wherein, the actual water content corresponding to the initial temperature T1 and the initial pressure P1 is M1, and the actual salt content is N1; the maximum water content corresponding to the target temperature T2 and the initial pressure P1 is M2, and the maximum salt content is N2; the maximum water content corresponding to the throttling temperature T3 and the throttling pressure P2 is M3, and the maximum salt content is N3, and M2 > M3 ≥ M1, N2 > N3 ≥ N1.

9. The preheating control method for preventing water and salt precipitation as described in claim 8, characterized in that: The methods for obtaining the maximum water content M2 and maximum salinity N2 corresponding to the target temperature T2, and the maximum water content M3 and maximum salinity N3 corresponding to the throttling temperature T3 and throttling pressure P2, include: Establish simulation models including solid salt flow SALT, water flow H2O, mixer MIX, gas-liquid separator SP, and air flow AIR; The solid salt stream SALT and the water stream H2O are introduced into the mixer MIX and mixed to obtain a mixed liquid stream SOLU. The mixed liquid stream SOLU is introduced into the gas-liquid separator SP, and air stream AIR is introduced into the gas-liquid separator SP for gas-liquid separation. Set the temperature and pressure parameters of the gas phase stream GAS output by the gas-liquid separator SP, obtain the corresponding composition parameters, and substitute the composition parameters into the maximum water content calculation formula and the maximum salinity calculation formula to obtain the maximum water content and maximum salinity under different temperature and pressure conditions.

10. The preheating control method for preventing water and salt precipitation as described in claim 9, characterized in that: Based on the maximum water content and maximum salinity under different temperature and pressure conditions, respectively, the curve set H of the relationship between the maximum water content and pressure at different temperatures and the curve set L of the relationship between the maximum salinity and pressure at different temperatures were obtained. The actual water content M1 and actual salt content N1 of the high-pressure air extracted from the gas storage tank (200) are used as the water separation judgment benchmark value and salt separation judgment benchmark value, respectively. Based on the temperature parameters corresponding to the positions after preheating, throttling, and each process position during expansion, the target curve at the corresponding temperature is determined in the relationship curve group H and the relationship curve group L. Combined with the corresponding pressure parameters, the maximum water content and maximum salinity corresponding to each process position are determined. When the maximum water content at each process location is greater than M1 and the maximum salt content at each process location is greater than N1, it is determined that no water or salt precipitation occurs in the high-pressure air during preheating, throttling and subsequent expansion processes. Based on the relationship curve set H and the relationship curve set L, the minimum throttling temperature T3 that simultaneously satisfies M3≥M1 and N3≥N1 under the throttling pressure P2 is determined, and the target temperature T2 after preheating is deduced accordingly.

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