Compressed air energy storage underground artificial cavern gas storage and cavern gas leakage rate calculation and evaluation method

Abstract

The application provides a compressed air energy storage underground artificial cavern gas storage and a cavern gas storage gas leakage rate calculation and evaluation method, the gas storage comprises a gas storage cavity, a gas storage lining and surrounding rock, wherein the gas storage is deeply buried in a hard rock stratum underground; the method is suitable for the compressed air energy storage underground artificial cavern gas storage; the method comprises the following steps: S1, determining a real-time temperature field of the gas storage; S2, carrying out spatial finite difference on the gas storage cavity; S3, calculating the amount of gas substance in an arbitrary hexahedral small block space; S4, calculating the total amount of gas substance in the gas storage cavity; S5, calculating a real-time leakage rate of the gas storage; S6, calculating a 24-hour leakage rate of the gas storage; S7, evaluating the leakage of the gas storage; the method is simple in calculation, sensitive in response, can real-timely, quantitatively and accurately feed back the leakage rate change of the gas storage, and has great significance for health state evaluation and safe operation of the compressed air energy storage power station.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage technology, and in particular to underground artificial chamber gas storage facilities for compressed air energy storage and methods for calculating and evaluating the gas leakage rate of such facilities. Background Technology

[0002] Traditional gas storage leakage assessment methods typically calculate leakage rates solely based on changes in gas pressure. This method requires eliminating the influence of temperature on storage pressure and necessitates waiting for the gas temperature field within the storage to stabilize, which often takes more than 3 days. However, compressed air energy storage power stations generally need to complete one inflation, pressure holding, and deflation cycle per day. Using traditional methods to assess gas storage leakage would require the compressed air energy storage power station to be shut down for an extended period, resulting in significant economic losses. Summary of the Invention

[0003] To solve the above-mentioned technical problems, one of the technical solutions adopted by the present invention is: an underground artificial cavern gas storage facility for compressed air energy storage, the gas storage facility comprising:

[0004] Gas storage chamber 1;

[0005] The gas storage liner 2 is located on the inner surface of the gas storage cavity 1;

[0006] Surrounding rock 3 is located on the outer surface of the gas storage cavity 1;

[0007] The gas storage facility is buried deep within hard rock strata.

[0008] Furthermore, a series of temperature sensors should be embedded inside the gas storage chamber 1 to obtain the real-time temperature of a local area of ​​the gas storage chamber 1.

[0009] Another technical solution adopted in this invention is: a method for calculating and evaluating the gas leakage rate of a chambered gas storage facility. This method is applicable to the aforementioned underground artificial chambered gas storage facility for compressed air energy storage. The method includes:

[0010] S1. Determine the real-time temperature field of the gas storage facility;

[0011] S2, finite difference in the cavity space of the gas storage tank;

[0012] S3. Calculate the amount of gaseous substance in any small hexahedral space;

[0013] S4. Calculate the total amount of gas in the gas storage chamber;

[0014] S5. Calculate the real-time leakage rate of the gas storage facility;

[0015] S6. Calculate the leakage rate of the gas storage facility over 24 hours;

[0016] S7. Assessment of gas storage facility leaks.

[0017] Furthermore, in S1, by embedding a temperature sensor in the gas storage cavity 1, the real-time temperature of a local area of ​​the gas storage cavity 1 is obtained, and the real-time temperature field of the entire gas storage cavity 1 is determined by natural neighborhood interpolation or numerical methods.

[0018] Furthermore, in S2, the gas storage chamber is divided into a certain number of hexahedral blocks with finite difference. The volume of the hexahedral blocks is determined by the temperature field, and the gas temperature difference between different parts within a single hexahedral block is required to be no more than 0.1K.

[0019] Furthermore, in S3, the ideal gas law is:

[0020] PV = nRT

[0021] In the formula: P is the pressure, in Pa; V is the gas volume, in m³. 3 T is temperature, in K; n is the amount of substance of the gas, in mol; R is the universal gas constant, the value of which is related to the unit of the state parameter. In the International System of Units (SI), R = 8.31, with the unit J / mol·K.

[0022] Based on the ideal gas law, the amount of substance n of the gas in the i-th hexahedral sub-block is... i The formula is:

[0023]

[0024] In the formula: the gas pressure inside the i-th hexahedral sub-block is P. i The volume is V i The temperature is T i .

[0025] Furthermore, in S4, the formula for the total amount of gas n in the gas storage tank is:

[0026]

[0027] The gas storage volume is divided into m blocks.

[0028] Furthermore, in S5, during the pressure holding phase, the real-time leakage rate f of the gas storage tank at time t is... t The formula is:

[0029]

[0030] The total amount of gas in the storage tank at time t is calculated using the formula in S4. t The total amount of gas in the storage tank at time t+Δt can be obtained using the formula in S4.t+Δt .

[0031] Furthermore, in S6,

[0032] S601. If the leakage rate of the gas storage facility remains approximately constant during the pressure holding phase, then the leakage rate f of the gas storage facility within one day of pressure holding is... d for:

[0033]

[0034] Where, n pre n represents the total amount of gas in the cavity at the start of pressurization in the gas storage tank. aft The total amount of gas in the gas storage chamber at the end of the pressure holding period; t keep The duration of pressure holding in the gas storage facility, in hours;

[0035] S602. If the leakage rate of the gas storage facility fluctuates significantly during the pressure holding phase, a longer pressure holding period is required to understand the real-time leakage rate variation pattern. In this case, the leakage rate f of the gas storage facility after one day of pressure holding is... d for:

[0036]

[0037] Among them, f t Let t be the real-time leakage rate of the gas storage tank at time t in S5.

[0038] Furthermore, in S7, if the daily leakage rate of the gas storage facility is less than 0.5%, the gas storage facility is considered to have good sealing performance and can operate normally; if the daily leakage rate of the gas storage facility is between 0.5% and 2%, the gas storage facility is considered to have average sealing performance and the gas storage facility should be repaired as appropriate; if the daily leakage rate of the gas storage facility is greater than 2%, the gas storage facility should be repaired as soon as possible.

[0039] The advantages and positive effects of this invention are: the method is simple to calculate and has a sensitive response, and can provide real-time, quantitative and accurate feedback on the leakage rate changes of the gas storage tank, which is of great significance for the health status assessment and safe operation of compressed air energy storage power stations. Attached Figure Description

[0040] Figure 1 For the finite difference cross-section of the gas storage cavity space;

[0041] Figure 2 This is a finite difference longitudinal section view of the gas storage cavity space;

[0042] In the diagram: 1. Gas storage lining; 2. Gas storage cavity; 3. Surrounding rock. Detailed Implementation

[0043] To better understand the present invention, the present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0044] Example 1

[0045] like Figure 1-2 As shown, the compressed air energy storage underground artificial chamber includes:

[0046] Gas storage chamber 1;

[0047] The gas storage liner 2 is located on the inner surface of the gas storage cavity 1;

[0048] Surrounding rock 3 is located on the outer surface of the gas storage cavity 1;

[0049] The gas storage facility is buried deep within hard rock strata.

[0050] Furthermore, a series of temperature sensors should be embedded inside the gas storage cavity 1 to obtain the real-time temperature of a local area of ​​the gas storage cavity 1, and to determine the real-time temperature field of the entire gas storage cavity 1 through natural neighborhood interpolation or numerical methods.

[0051] Example 2

[0052] A method for calculating and evaluating the gas leakage rate of a chambered gas storage facility, applicable to the compressed air energy storage underground artificial chambered gas storage facility described in Example 1 above, comprising:

[0053] S1. Determine the real-time temperature field of the gas storage facility;

[0054] Specifically, in S1, a temperature sensor is installed in the gas storage cavity 1 to obtain the real-time temperature of a local area of ​​the gas storage cavity 1, and the real-time temperature field of the entire gas storage cavity 1 is determined by natural neighborhood interpolation or numerical methods.

[0055] When dividing the gas storage cavity into finite differences, a polar coordinate system is established on any cross-section of the gas storage cavity, with the center of the circle as the pole. Since the gas inside the gas storage cavity continuously exchanges heat with the gas storage lining 2, the gas temperature distribution field is closely related to the polar radius of the polar coordinate system, while the influence of the polar angle is relatively small. Therefore, a sector-shaped cutting method is used on the cross-section of the gas storage cavity; that is, the circular cross-section of the gas storage cavity is first divided into a certain number of rings, and then further divided into smaller sector-shaped ring blocks.

[0056] In the longitudinal direction of the gas storage facility, due to the "sealed roof effect", the temperature at the gas inlet is generally lower than the temperature at the end. The temperature difference between the two ends of the gas storage facility is often much greater than the temperature difference within any cross section. Therefore, the spacing between the sections in the longitudinal direction of the gas storage facility can be appropriately reduced.

[0057] S2, finite difference in the cavity space of the gas storage tank;

[0058] Specifically, in S2, the gas storage chamber is divided into a certain number of hexahedral blocks with a finite difference. The volume of the hexahedral block is determined by the temperature field, and the gas temperature difference between different parts within a single hexahedral block is required to be no more than 0.1K.

[0059] S3. Calculate the amount of gaseous substance in any small hexahedral space;

[0060] Specifically, in S3, the ideal gas law is:

[0061] PV = nRT

[0062] In the formula: P is the pressure, in Pa; V is the gas volume, in m³. 3 T is temperature, in K; n is the amount of substance of the gas, in mol; R is the universal gas constant, the value of which is related to the unit of the state parameter. In the International System of Units (SI), R = 8.31, with the unit J / mol·K.

[0063] Based on the ideal gas law, the amount of substance n of the gas in the i-th hexahedral sub-block is... i The formula is:

[0064]

[0065] In the formula: the gas pressure inside the i-th hexahedral sub-block is P. i The volume is V i The temperature is T i .

[0066] Based on Pascal's law, the pressure of a static fluid in a closed space is constant everywhere. During the pressurization phase of a gas storage tank, the tank is in a closed state with relatively slow gas flow. Therefore, the pressure within the storage tank can be considered constant at any given moment. If the pressure of the gas storage tank at any given moment is P (obtained through real-time pressure monitoring), then the pressure P of the hexahedral sub-block at that moment is... i =P;V i The volume of the i-th hexahedral blocks is calculated. Since the pressure change in the gas storage tank under pressure-holding conditions is small, the resulting change in cavity volume due to pressure changes is negligible. i The temperature field at this location is solved using the volume average method.

[0067] S4. Calculate the total amount of gas in the gas storage chamber;

[0068] Specifically, in S4, the formula for the total amount of gas n in the gas storage tank is:

[0069]

[0070] The gas storage volume is divided into m blocks.

[0071] S5. Calculate the real-time leakage rate of the gas storage facility;

[0072] Specifically, in S5, during the pressure holding phase, the real-time leakage rate f of the gas storage tank at time t is... t The formula is:

[0073]

[0074] The total amount of gas in the storage tank at time t is calculated using the formula in S4. t The total amount of gas in the storage tank at time t+Δt can be obtained using the formula in S4. t+Δt .

[0075] S6. Calculate the leakage rate of the gas storage facility over 24 hours;

[0076] Specifically, in S6,

[0077] S601. If the leakage rate of the gas storage facility remains approximately constant during the pressure holding phase, then the leakage rate f of the gas storage facility within one day of pressure holding is... d for:

[0078]

[0079] Where, n pre n represents the total amount of gas in the cavity at the start of pressurization in the gas storage tank. aft The total amount of gas in the gas storage chamber at the end of the pressure holding period; t keep The duration of pressure holding in the gas storage facility, in hours;

[0080] S602. If the leakage rate of the gas storage facility fluctuates significantly during the pressure holding phase, a longer pressure holding period is required to understand the real-time leakage rate variation pattern. In this case, the leakage rate f of the gas storage facility after one day of pressure holding is... d for:

[0081]

[0082] Among them, f t Let t be the real-time leakage rate of the gas storage tank at time t in S5.

[0083] S7. Assessment of gas storage facility leaks.

[0084] Specifically, in S7, if the daily leakage rate of the gas storage facility is less than 0.5%, the gas storage facility is considered to have good sealing performance and can operate normally; if the daily leakage rate of the gas storage facility is between 0.5% and 2%, the gas storage facility is considered to have average sealing performance and the gas storage facility should be repaired as appropriate; if the daily leakage rate of the gas storage facility is greater than 2%, the gas storage facility should be repaired as soon as possible.

[0085] This method is simple to calculate and has a sensitive response. It can provide real-time, quantitative, and accurate feedback on the leakage rate changes of the gas storage facility, which is of great significance for the health status assessment and safe operation of compressed air energy storage power stations.

[0086] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of this patent.

Claims

1. A method for calculating and evaluating gas leakage rate of a cavern gas storage, characterized in that: The method is suitable for compressed air energy storage underground artificial chamber gas storage, and the compressed air energy storage underground artificial chamber gas storage comprises a gas storage cavity (1); A gas storage lining (2) is located on the inner surface of the gas storage cavity (1); Surrounding rock (3) is located on the outer surface of the gas storage cavity (1); Wherein, the gas storage is deeply buried in the underground hard rock stratum; A series of temperature sensors should be embedded in the gas storage cavity (1) to obtain the real-time temperature of the local area of the gas storage cavity (1); The method comprises: S1, determine the real-time temperature field of the gas storage; In S1, the real-time temperature of the local area of the gas storage cavity (1) is obtained by embedding temperature sensors in the gas storage cavity (1), and the real-time temperature field of the entire gas storage cavity (1) is determined by natural neighborhood interpolation method or numerical method; S2, gas storage cavity space finite difference; In S2, the gas storage cavity is divided into a certain number of hexahedral small blocks, and the volume of the hexahedral small block is determined by the temperature field, and the gas temperature difference of different parts in a single hexahedral small block is required to be not more than 0.1K; S3, calculate the amount of gas matter in any hexahedral small block space; In S3, the ideal gas state equation is: PV=nRT, wherein: P is the pressure in Pa; V is the volume of the gas in ; T is the temperature in K; n is the amount of substance of the gas in mol; R is the universal gas constant, which depends on the units of the state parameters, in the International System of Units R = 8.31 in J / mol•K; Based on the ideal gas state equation, the amount of substance n of the space gas of the i-th hexahedral small block i is given by the formula: ， wherein: the gas pressure within the ith hexahedral element of the volume is P i , the volume is V i , and the temperature is T i ; In S4, the formula of the total amount of gas matter n in the gas storage is: ， Wherein, the volume of the gas storage is divided into m blocks; S4, calculate the total amount of gas matter in the gas storage cavity; In S4, the formula of the total amount of gas matter n in the gas storage is: ， Wherein, the volume of the gas storage is divided into m blocks; S5, calculate the real-time leakage rate of the gas storage; In S5, in the pressure maintaining phase, the real-time leakage rate of the gas storage at time t The formula is: ， wherein the total amount of gas substance n in the gas storage at time t is calculated by the formula in S4 t wherein the total amount of gas substance n in the gas storage at time t+Δt is calculated by the formula in S4 t+Δt ; S6, calculate the 24-hour leakage rate of the gas storage; In S6, S601、If the leakage rate of the gas storage is substantially constant during the pressure maintaining phase, the leakage rate f of the gas storage within one day of pressure maintaining is: d is: ， wherein, total amount of substance of gas in the cavity at the beginning of the pressure maintenance of the gas reservoir; total amount of substance of gas in the cavity at the end of the pressure maintenance of the gas reservoir; is the duration of the pressure maintenance of the gas reservoir, in hours. S602、If the fluctuation range of the leakage rate of the gas storage is large in the pressure maintaining stage, the pressure needs to be maintained for a long time, and the change rule of the real-time leakage rate of the gas storage is grasped. At this time, the leakage rate f of the gas storage in one day of pressure maintenance is d is: ， wherein, is the real-time leakage rate of the gas storage at time t in S5; S7, evaluation of gas storage leakage.

2. The method according to claim 1, wherein: In S7, if the one-day leakage rate of the gas storage is less than 0.5%, it is considered that the sealing performance of the gas storage is good, and the gas storage can operate normally; if the one-day leakage rate of the gas storage is 0.5%-2%, it is considered that the sealing performance of the gas storage is general, and the gas storage is repaired according to the situation; if the one-day leakage rate of the gas storage is greater than 2%, the gas storage should be repaired as soon as possible.

Images