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

Abstract

The invention provides a compressed air energy storage underground artificial chamber gas storage and a chamber gas storage gas leakage rate calculation and evaluation method.The gas storage comprises a gas storage cavity, a gas storage lining and surrounding rock, and the gas storage is deeply buried in an underground hard rock stratum; the method is suitable for the compressed air energy storage underground artificial chamber gas storage. The method comprises the following steps: S1, determining a real-time temperature field of the gas storage; s2, finite difference of the cavity space of the gas storage is carried out; s3, calculating the amount of gas substances in any small hexahedral space; s4, calculating the total substance amount of the gas in the inner cavity of the gas storage; s5, calculating the real-time leakage rate of the gas storage; s6, the 24-hour leakage rate of the gas storage is calculated; s7, evaluating the leakage of the gas storage; the method is simple in calculation and sensitive in response, can quantitatively and accurately feed back the change condition of the leakage rate of the gas storage in real time, and is of great significance to health state evaluation and safe operation of a compressed air energy storage power station.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage, and in particular to an underground artificial cavern gas storage for compressed air energy storage and a method for calculating and evaluating the gas leakage rate of the cavern gas storage. Background Art

[0002] Traditional gas storage gas leakage assessment methods generally only calculate the gas storage leakage rate through changes in gas pressure. This method needs to be able to eliminate the impact of the temperature field on the gas storage pressure and must wait until the gas temperature field in the gas storage is stable before it can be performed. This often takes more than 3 days. However, a compressed air energy storage power station generally completes an inflation, pressure maintenance and deflation cycle within a day. Using traditional methods to assess the leakage status of a gas storage reservoir will require the compressed air energy storage power station to be shut down for a long time, resulting in greater economic losses. Summary of the invention

[0003] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is: a compressed air energy storage underground artificial cavern gas storage, which includes:

[0004] Gas storage cavity 1;

[0005] A gas storage reservoir lining 2, which is located on the inner surface of the gas storage reservoir cavity 1;

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

[0007] Among them, the gas storage is buried deep in the underground hard rock formation.

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

[0009] Another technical solution adopted by the present invention is: a method for calculating and evaluating the gas leakage rate of a chamber gas storage reservoir, which is applicable to the above-mentioned compressed air energy storage underground artificial chamber gas storage reservoir, and the method comprises:

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

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

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

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

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

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

[0016] S7. Assessment of gas storage leakage.

[0017] Furthermore, in S1, a temperature sensor is buried 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 the natural neighbor interpolation method or the numerical method.

[0018] Furthermore, in S2, the gas storage cavity is divided into a certain number of hexahedral blocks by finite difference. The volume of the hexahedral blocks is determined by the temperature field, and the temperature difference of the gas at different parts within a single hexahedral block is required not to exceed 0.1K.

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

[0020] PV=nRT

[0021] Where: P is pressure, unit is Pa; V is gas volume, unit is m 3 ; T is temperature, unit is K; n is the amount of gas substance, unit is mol; R is the universal gas constant, its value is related to the unit of state parameter, in the International System of Units R = 8.31, unit is J / mol·K;

[0022] Based on the ideal gas state equation, the amount of gas in the i-th hexahedral block is n i The formula is:

[0023]

[0024] Where: The gas pressure in the space of the i-th hexahedral block is P i , the volume is V i , temperature is T i .

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

[0026]

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

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

[0029]

[0030] Among them, the total amount of gas in the gas storage at time t is calculated by the formula in S4: t , the total amount of gas in the gas storage at time t+Δt is obtained by the formula in S4t+Δt .

[0031] Furthermore, in S6,

[0032] S601. If the leakage rate of the gas storage remains roughly constant during the pressure maintenance stage, the leakage rate of the gas storage within one day of pressure maintenance is f d for:

[0033]

[0034] Among them, n pre The total amount of gas in the cavity when the gas storage reservoir starts to maintain pressure; n aft The total amount of gas in the cavity at the end of the gas storage pressure maintenance; t keep The duration of gas storage pressure maintenance, in hours;

[0035] S602. If the gas storage leakage rate fluctuates greatly during the pressure maintenance stage, it is necessary to maintain the pressure for a longer period of time to understand the change law of the gas storage leakage rate in real time. At this time, the gas storage leakage rate f d for:

[0036]

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

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

[0039] The advantages and positive effects of the present invention are: the method is simple to calculate and sensitive to response, and can provide real-time, quantitative and accurate feedback on changes in the leakage rate of the gas storage reservoir, which is of great significance to the health status assessment and safe operation of compressed air energy storage power stations. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0041] Figure 2 It is the finite difference longitudinal section diagram of the gas storage cavity space;

[0042] In the figure: 1. Gas storage reservoir lining; 2. Gas storage reservoir cavity; 3. Surrounding rock. DETAILED DESCRIPTION

[0043] In order to better understand the present invention, the present invention is further described below in conjunction with specific embodiments and drawings.

[0044] Example 1

[0045] like Figure 1-2 As shown, a compressed air energy storage underground artificial cavern gas storage includes:

[0046] Gas storage cavity 1;

[0047] A gas storage reservoir lining 2, which is located on the inner surface of the gas storage reservoir cavity 1;

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

[0049] Among them, the gas storage is buried deep in the underground hard rock formation.

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

[0051] Example 2

[0052] A method for calculating and evaluating the gas leakage rate of a chamber gas storage reservoir, which is applicable to the compressed air energy storage underground artificial chamber gas storage reservoir described in the above embodiment 1, and comprises:

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

[0054] Specifically, in S1, a temperature sensor is buried 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 the natural neighbor interpolation method or the numerical method.

[0055] When the gas storage cavity is finitely differentiated, a polar coordinate system is established with the center of the circle as the pole on any cross section of the gas storage. Since the gas in the gas storage cavity will always exchange heat with the gas storage lining 2, the gas temperature distribution field of the gas storage is closely related to the polar diameter of the polar coordinate system, but has a relatively small influence on the polar angle. Therefore, the fan-shaped cutting method is used on the cross section of the gas storage, that is, the circular section of the gas storage is first divided into a certain number of circular rings, and then divided into small fan-shaped circular ring blocks;

[0056] In the longitudinal direction of the gas storage reservoir, due to the "buffered ceiling effect" of the gas storage reservoir, the air inlet temperature of the gas storage reservoir is generally lower than the end temperature, and the temperature difference at both ends of the gas storage reservoir is often far greater than the temperature difference in any cross section. Therefore, the dividing spacing in the longitudinal direction of the gas storage reservoir can be appropriately reduced.

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

[0058] Specifically, in S2, the gas storage cavity is divided into a certain number of hexahedral blocks by finite difference. The volume of the hexahedral blocks is determined by the temperature field, and the temperature difference of the gas at different parts within a single hexahedral block is required not to exceed 0.1K.

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

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

[0061] PV=nRT

[0062] Where: P is pressure, unit is Pa; V is gas volume, unit is m 3 ; T is temperature, unit is K; n is the amount of gas substance, unit is mol; R is the universal gas constant, its value is related to the unit of state parameter, in the International System of Units R = 8.31, unit is J / mol·K;

[0063] Based on the ideal gas state equation, the amount of gas in the i-th hexahedral block is n i The formula is:

[0064]

[0065] Where: The gas pressure in the space of the i-th hexahedral block is P i , the volume is V i , temperature is T i .

[0066] Among them, based on Pascal's law, the pressure of the static fluid in a closed space is equal everywhere. The gas storage reservoir is in a closed state during the pressure maintenance stage and the gas flow rate is relatively slow. Therefore, the pressure in the gas storage space at the same time can be considered to be equal everywhere. If the pressure of the gas storage reservoir at any time is P (obtained by arranging real-time pressure gauge monitoring), then the pressure of the hexahedral block at that time is P i =P;V i It is obtained by calculating the volume of the i-th hexahedral block. Since the pressure change of the gas storage reservoir is small under the pressure-maintaining state, the change of the cavity volume caused by the pressure change of the gas storage reservoir is very small and can be ignored; T i Based on the temperature field at this location, the volume averaging method is used to solve the problem.

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

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

[0069]

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

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

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

[0073]

[0074] Among them, the total amount of gas in the gas storage at time t is calculated by the formula in S4: t , the total amount of gas in the gas storage at time t+Δt is obtained by the formula in S4 t+Δt .

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

[0076] Specifically, in S6,

[0077] S601. If the leakage rate of the gas storage remains roughly constant during the pressure maintenance stage, the leakage rate of the gas storage within one day of pressure maintenance is f d for:

[0078]

[0079] Among them, n pre The total amount of gas in the cavity when the gas storage reservoir starts to maintain pressure; n aft The total amount of gas in the cavity at the end of the gas storage pressure maintenance; t keep The duration of gas storage pressure maintenance, in hours;

[0080] S602. If the gas storage leakage rate fluctuates greatly during the pressure maintenance stage, it is necessary to maintain the pressure for a longer period of time to understand the change law of the gas storage leakage rate in real time. At this time, the gas storage leakage rate f d for:

[0081]

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

[0083] S7. Assessment of gas storage leakage.

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

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

[0086] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation 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. Compressed air energy storage underground artificial chamber gas storage, characterized by: The gas storage facility includes: Gas storage chamber (1); A gas storage reservoir lining (2), which is located on the inner surface of the gas storage reservoir cavity (1); Surrounding rock (3), which is located on the outer surface of the gas storage cavity (1); Among them, the gas storage is buried deep in the underground hard rock formation.

2. The compressed air energy storage underground artificial cavern gas storage according to claim 1 is characterized in that: A series of temperature sensors should be embedded in the gas storage cavity (1) to obtain the real-time temperature of a local area of ​​the gas storage cavity (1).

3. A method for calculating and evaluating the gas leakage rate of a chamber gas storage, characterized in that: The method is applicable to the compressed air energy storage underground artificial cavern gas storage described in any one of claims 1-2, and the method comprises: S1. Determine the real-time temperature field of the gas storage; S2, finite difference of gas storage cavity space; S3. Calculate the amount of gaseous matter in any small hexahedral space; S4. Calculate the total amount of gas in the gas storage cavity; S5. Calculate the real-time leakage rate of the gas storage; S6. Calculate the leakage rate of the gas storage for 24 hours; S7. Assessment of gas storage leakage.

4. The method for calculating and evaluating the gas leakage rate of a chamber gas storage according to claim 3, characterized in that: In S1, a temperature sensor is buried 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 a natural neighbor interpolation method or a numerical method.

5. The method for calculating and evaluating gas leakage rate of a chamber gas storage according to claim 4, characterized in that: In S2, the gas storage cavity is divided into a certain number of hexahedral blocks by finite difference. The volume of the hexahedral blocks is determined by the temperature field, and the temperature difference of the gas at different parts within a single hexahedral block is required not to exceed 0.1K.

6. The compressed air energy storage underground artificial cavern gas storage according to claim 5 is characterized in that: In S3, the ideal gas state equation is: PV=nRT Where: P is pressure, unit is Pa; V is gas volume, unit is m 3 ; T is temperature, unit is K; n is the amount of gas substance, unit is mol; R is the universal gas constant, its value is related to the unit of state parameter, in the International System of Units R = 8.31, unit is J / mol·K; Based on the ideal gas state equation, the amount of gas in the i-th hexahedral block is n i The formula is: Where: The gas pressure in the space of the i-th hexahedral block is P i , the volume is V i , temperature is T i .

7. The compressed air energy storage underground artificial cavern gas storage according to claim 6 is characterized by: In S4, the formula for the total amount of gas n in the gas storage reservoir is: The gas storage volume is divided into m blocks.

8. The compressed air energy storage underground artificial cavern gas storage according to claim 4 is characterized by: In S5, during the pressure maintenance phase, the real-time leakage rate f of the gas storage at time t is t The formula is: Among them, the total amount of gas in the gas storage at time t is calculated by the formula in S4: t , the total amount of gas in the gas storage at time t+Δt is obtained by the formula in S4 t+Δt .

9. The compressed air energy storage underground artificial cavern gas storage according to claim 7 is characterized in that: In S6, S601. If the leakage rate of the gas storage remains roughly constant during the pressure maintenance stage, the leakage rate of the gas storage within one day of pressure maintenance is f d for: Among them, n pre The total amount of gas in the cavity when the gas storage reservoir starts to maintain pressure; n aft The total amount of gas in the cavity at the end of the gas storage pressure maintenance; t keep The duration of gas storage pressure maintenance, in hours; S602. If the gas storage leakage rate fluctuates greatly during the pressure maintenance stage, it is necessary to maintain the pressure for a longer period of time to understand the change law of the gas storage leakage rate in real time. At this time, the gas storage leakage rate f d for: f d =∫0 24 f t dt Among them, f t is the real-time leakage rate of the gas storage at time t in S5.

10. The compressed air energy storage underground artificial cavern gas storage according to claim 8, characterized in that: In S7, if the daily leakage rate of the gas storage reservoir is lower than 0.5%, it is considered that the sealing performance of the gas storage reservoir is good and the gas storage reservoir can operate normally; if the daily leakage rate of the gas storage reservoir is between 0.5% and 2%, it is considered that the sealing performance of the gas storage reservoir is average and the gas storage reservoir should be repaired as appropriate; if the daily leakage rate of the gas storage reservoir is greater than 2%, the gas storage reservoir should be repaired as soon as possible.

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