Tank leakage monitoring method and system

Abstract

The invention discloses a tank leakage monitoring method and system, belongs to the technical field of leakage monitoring, and aims to solve the problems that the monitoring accuracy is reduced and the leakage position cannot be accurately positioned due to the fact that optical fiber sensors are arranged in an inner tank of a crude oil storage tank and are influenced by the environment. Generating a temperature matrix, calculating a fitting position corresponding to each temperature by using a temperature-position fitting function, making a difference between the fitting position and the actual position of the sensor, judging that the point is abnormal and leaks when the difference exceeds an error threshold and the temperature difference at adjacent moments exceeds the temperature threshold, and positioning a leakage point according to the fitting position calculated by the abnormal temperature. The measurement precision is improved, and a leakage point is accurately positioned.

Description

Technical Field

[0001] The invention belongs to the technical field of leakage monitoring, and relates to a tank leakage monitoring method and system. Background Art

[0002] Crude oil storage tanks are important equipment for storing crude oil. Once a leak occurs in a crude oil storage tank, a large amount of crude oil liquid will evaporate, quickly forming an air mass that will automatically detonate in the atmosphere, eventually causing explosions and fires, posing a huge threat to people's lives and property. At the same time, the toxic chemicals in crude oil will pollute the environment. At present, the method of monitoring tank leakage is manual monitoring, specifically through manual visual inspection or using portable instruments to measure information to make judgments, but manual visual inspection has the problems of untimely monitoring and wasting manpower and material resources; using sensors and detectors to monitor leaks, this method has few monitoring points, is easily affected by complex environments, has low monitoring accuracy, cannot accurately locate the leakage point, and is prone to safety accidents.

[0003] For example, a Chinese patent with the authorization publication number CN112781810B discloses a method, device and system for detecting tank leakage, which belongs to the field of tank safety detection technology. The method includes: obtaining a first optical signal carrying optical fiber position information after passing through the optical fiber; obtaining a second optical signal carrying optical fiber position information after passing through the optical fiber; controlling the first optical signal to be coherent with a reference optical signal to obtain a coherent optical beat signal; processing the coherent optical beat signal and the second optical signal respectively to obtain a relative frequency shift corresponding to the coherent optical beat signal and a Rayleigh scattering phase change and light intensity change corresponding to the second optical signal; determining a state cloud map based on the relative frequency shift; determining vibration parameters based on the Rayleigh scattering phase change and the light intensity change; judging whether the tank has a leak based on the state cloud map, the vibration parameters and the leakage judgment condition.

[0004] For example, the Chinese patent with publication number CN111061275A discloses a tank leakage image detection robot, including a body platform, a driving device, a driven device, a data processor, a power supply device, a main controller, a human-machine interface, an extended antenna, an alarm device, an anti-collision device and a camera device; the driving device and the driven device are installed at both ends of the bottom of the body platform in an aligned manner; the top of the body platform is connected with a data processor, a power supply device, a main controller, a human-machine interface, an extended antenna, an alarm device, an anti-collision device and a camera device; wherein the anti-collision device, the camera device and the driving device are at one end of the body platform; the main controller is electrically connected to the alarm device, the anti-collision device, the data processor, the human-machine interface, the power supply device and the driving device respectively; the data processor is electrically connected to the extended antenna and the camera device respectively; and the use method of the robot. This patent can effectively and accurately detect the leakage of the storage tank.

[0005] However, the above content does not take into account the problem that the monitoring accuracy is reduced due to the influence of complex environment and the position of small leakage points cannot be accurately located. Summary of the invention

[0006] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a tank leakage monitoring method and system to solve the problem that the monitoring methods in the prior art do not take complex environments into consideration, resulting in reduced monitoring accuracy.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A tank leakage monitoring method comprises the following steps:

[0009] Step 1, collecting the temperature of a monitoring point, where the monitoring point is set on the tank body of the oil storage tank;

[0010] Step 2, according to the temperature range to which the temperature of the monitoring point belongs, input it into the corresponding temperature-position fitting function calculation formula to obtain the position of the monitoring point in the oil storage tank; obtain the position values ​​of the same monitoring point at two moments, and obtain the position difference after subtracting the two position values; in the temperature-position fitting function, different temperature ranges correspond to different calculation formulas;

[0011] Step 3, compare the position difference and the error threshold. If the position difference exceeds the error threshold, the monitoring point is considered to be leaking, and the position of the leak point is determined based on the position value measured at the second moment.

[0012] A further improvement of the present invention is:

[0013] Preferably, the monitoring points are distributed in a grid-like pattern on the tank body.

[0014] Preferably, a temperature matrix is ​​obtained by point distribution in the form of a grid, and each element in the temperature matrix corresponds to the position of a monitoring point on the tank body.

[0015] Preferably, the temperature of the monitoring point is obtained by measuring the light intensity signal of the sensing optical fiber.

[0016] Preferably, the formula for calculating the temperature of the monitoring point through the light intensity signal is:

[0017]

[0018] Where a is the temperature correlation coefficient, h is the Planck constant, c is the speed of light in vacuum, v is the Raman shift, k is the Boltzmann constant, and k t Indicates the thermostat adjustment coefficient, I a Represents the Anti-Stokes light intensity, Is Indicates the intensity of Stokes light.

[0019] Preferably, the temperature-position fitting function is:

[0020]

[0021] Where y represents the temperature t ij The fitting distance from the point to the bottom of the tank, A1-A4, B1-B4, C1-C4, D1-D4 and E1-E4 represent constant coefficients, A1=4.40873, B1=37.667901, C1=117.20747, D1=1621.70629, E1=-109,693.1109, A2=2.0356, B2=32.83815, C2=143.82778, D2=1846 .13962, E2=-86, 138.3242, A3=1.65412, B3=87.70538, C3=172.46875, D3=1516.61181, E3=-49 97341.38611, A4=3.77297, B4=52.11203, C4=406.08675, D4=3551.06672, E4=-8202960.53222.

[0022] Preferably, in step 3, the error threshold is 5 mm.

[0023] A tank leakage monitoring system for implementing the above monitoring method comprises:

[0024] Data acquisition equipment, used to collect the temperature of the monitoring point;

[0025] The data processing device is used to input the temperature range to which the temperature of the monitoring point belongs into the corresponding temperature-position fitting function to obtain the position of the monitoring point in the oil storage tank; obtain the position values ​​of the same monitoring point at two moments, and obtain the position difference after subtracting the two position values; compare the position difference with the error threshold, if the position difference exceeds the error threshold, it is determined that the monitoring point is leaking, and the position of the leakage point is determined according to the position value measured at the second moment.

[0026] Preferably, it also includes a display device and an alarm device, and both the display device and the alarm device are connected to the data processing device.

[0027] Preferably, the data acquisition equipment includes a light source, a constant temperature box, a coupler, a long-wave filter, a short-wave filter and a detector; the light source is connected to the coupler, the coupler is connected to the constant temperature box, and the constant temperature box is connected to the distributed optical fiber sensor; the coupler is connected to the long-wave filter and the short-wave filter at the same time, the long-wave filter and the short-wave filter are both connected to the detector, and the detector is connected to the data processing equipment.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The invention discloses a tank leakage monitoring method, which belongs to the technical field of leakage monitoring. In order to solve the problem that the optical fiber sensor arranged in the crude oil storage tank is affected by the environment, resulting in a decrease in monitoring accuracy and an inability to accurately locate the leakage position, the invention collects temperature data of each sensor monitoring point in real time, generates a temperature matrix, uses a temperature-position fitting function, calculates the fitting position corresponding to each temperature, and makes a difference with the actual position of the sensor. When the error threshold is exceeded and the temperature difference at adjacent moments exceeds the temperature threshold, it is determined that the point is abnormal and a leakage occurs. The leakage point is located according to the fitting position calculated by the abnormal temperature, thereby improving the measurement accuracy and accurately locating the leakage point.

[0030] Furthermore, the present invention provides a tank leakage monitoring method. Furthermore, the temperature on the tank is distributed in a point-like manner, and the temperature of each position of the oil storage tank can be monitored.

[0031] Furthermore, by laying distributed optical fiber sensors in a grid shape on the tank body, the temperature data of each sensor monitoring point is collected in real time to generate a temperature matrix; the distributed optical fiber sensors can monitor the temperature of multiple positions at the same time, and use the temperature-position fitting function to calculate the fitting position corresponding to each temperature, and make a difference with the actual position of the sensor. When the error threshold is exceeded and the temperature difference at adjacent moments exceeds the temperature threshold, it is determined that the point is abnormal and a leak has occurred. The leak point is located according to the fitting position calculated according to the abnormal temperature, which improves the measurement accuracy and accurately locates tiny leaks.

[0032] The present invention also discloses a tank leakage monitoring system, which can obtain the location of the monitoring point through data acquisition equipment and data processing equipment. A thermostat is installed in the distributed optical fiber sensor, so that the sensor works at a constant temperature and is not affected by the ambient temperature. The distributed optical fiber sensor is laid in a grid shape on the tank. The system is comprehensive in function. A thermostat is installed in the distributed optical fiber sensor, so that the sensor works at a constant temperature and is not affected by the tank temperature in the crude oil storage tank. The distributed optical fiber sensor is laid in a grid shape on the tank. The temperature data of each sensor monitoring point is collected in real time, and a temperature matrix is ​​generated. The fitting position corresponding to each temperature is calculated using the temperature-position fitting function, and the difference is made with the actual position of the sensor. When the error threshold is exceeded and the temperature difference at adjacent moments exceeds the temperature threshold, it is determined that the point is abnormal and leakage occurs. The leakage point is located according to the fitting position calculated by the abnormal temperature, which improves the measurement accuracy and accurately locates the leakage point.

[0033] Furthermore, the present invention optimizes and improves the existing tank leakage monitoring method and system in terms of architecture, operating steps and processes. The system has the advantages of simple process, low investment and operating costs, and low production cost, and improves the monitoring effect on the basis of the original monitoring system.

[0034] Furthermore, the present invention proposes to add a constant temperature box between the coupler and the sensing optical fiber in the distributed optical fiber sensor to control the temperature of the optical elements in the sensor and provide a temperature environment, which can enable the sensor to work normally in a complex environment and extend the service life of the distributed optical fiber sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A grid-like map of monitoring points set up for tank leaks;

[0036] Figure 2 It is a schematic diagram of the flow of the tank leakage monitoring method of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of the distributed optical fiber sensor of the present invention;

[0038] Figure 4 It is a schematic diagram of the structure of the tank leakage monitoring system of the present invention.

[0039] Among them, 1 is the oil storage tank; 2 is the sensing optical fiber; and 3 is the measurement point. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0041] See also Figure 1 One embodiment of the present invention discloses a tank leakage monitoring method, comprising the following steps:

[0042] S1: A distributed optical fiber sensor is laid outside the shell of the oil storage tank 1, which is a sensing optical fiber 2; for details, see Figure 2 Along the height of the tank body, each circle of sensing optical fiber is arranged in an array along the height of the tank body, and a number of measuring points 3 are set on a circle of optical fiber, so that the distributed optical fiber sensor is distributed in a grid point shape around the tank body, and can collect the temperature of multiple positions on the tank body.

[0043] The temperature of the area where the sensor is located is calculated through the light intensity signal. The calculation formula is:

[0044]

[0045] Where a is the temperature correlation coefficient, h is the Planck constant, c is the speed of light in vacuum, v is the Raman shift, k is the Boltzmann constant, and k t Indicates the thermostat adjustment coefficient, I a Represents the Anti-Stokes light intensity, I s Represents the intensity of Stokes light, and the two light intensities are acquisition signals.

[0046] S2: Generate a temperature matrix according to the temperatures collected at each monitoring point. The temperature matrix is ​​a temperature matrix set according to a grid, as shown in the following formula;

[0047]

[0048] Among them, T s is the temperature matrix at time s, t ij Represents the temperature value monitored by the i-th and j-th temperature sensors in the grid; where i is the row number of the sensing optical fiber where the collection point is located, and j is the column where the collection point is located on the sensing optical fiber of each row.

[0049] S3: using the temperature matrix to determine the temperature-position fitting function to be used, and calculating the position corresponding to each element in the temperature matrix according to the temperature matrix and the fitting function;

[0050] The temperature-position fitting function is:

[0051]

[0052] Where y represents the temperature t ijThe fitting distance from the point to the bottom of the tank, A1-A4, B1-B4, C1-C4, D1-D4 and E1-E4 represent constant coefficients, A1=4.40873, B1=37.667901, C1=117.20747, D1=1621.70629, E1=-109,693.1109, A2=2.0356, B2=32.83815, C2=143.82778, D2=1846 .13962, E2=-86, 138.3242, A3=1.65412, B3=87.70538, C3=172.46875, D3=1516.61181, E3=-49 97341.38611, A4=3.77297, B4=52.11203, C4=406.08675, D4=3551.06672, E4=-8202960.53222.

[0053] Refer to formula (3), which consists of four formulas. According to the temperature range of the collected collection point temperature tij, the y value corresponding to the temperature is calculated by different formulas, and the y value difference between two moments at the same collection point is calculated as the position difference of the same collection point.

[0054] Crude oil storage tanks are mostly cylindrical, with little change in height, different volumes, and many diameter adjustments, so that the volume of the tank can meet the use requirements; according to experience, actual leakage mostly occurs in the middle and lower parts of the tank. On this basis, distributed optical fiber sensors are mostly set in the middle and lower parts of the tank. Since the height of general tanks is not much different, the volume is mostly due to the change in diameter, and formula (3) only considers the height of the tank. Therefore, the present invention recognizes formula (3) as a general formula. The various coefficients in this formula are obtained by fitting the actual values ​​of temperature and position measured in the tank test.

[0055] S4: Set the error threshold, compare the position difference and error threshold between the position corresponding to the temperature matrix element of the same measurement point and the actual monitoring point. If the position difference exceeds the error threshold, combined with the abnormal temperature judgment, the position is judged to be leaking, and the fitting position calculated according to the abnormal temperature measured for the second time is used to locate the leakage point, and an alarm message is issued.

[0056] Preferably, the error threshold is 5 mm.

[0057] One embodiment of the present invention discloses a tank leakage monitoring system, comprising:

[0058] See also Figure 3 , an embodiment of the present invention provides: a tank leakage monitoring system, specifically comprising:

[0059] The data acquisition equipment includes several distributed optical fiber sensors, which are used to collect real-time temperature information of each monitoring point of the tank body and transmit it to the data processing equipment through the wireless communication network; the distributed optical fiber sensor can also be other temperature measurement devices, as long as it can

[0060] The data processing device forms a temperature matrix with the temperature data, calculates the fitting position corresponding to each element of the temperature matrix by using the temperature-position fitting function, and makes a difference with the actual position of the distributed optical fiber sensor. If the difference exceeds the error threshold, the position is judged to be leaking in combination with another judgment method for judging leakage, and the leakage position is determined according to the actual position of the sensor, and a warning message is issued;

[0061] See also Figure 4 As a preferred embodiment, the system further comprises:

[0062] Display device, used to display monitored data information and alarm information; the display device can be a monitoring screen, display and other devices.

[0063] An alarm device is used to sound an alarm when receiving a warning message.

[0064] As one of the preferred embodiments, the data acquisition device includes a light source, a thermostat, a coupler, a long-wave filter, a short-wave filter and a detector; specifically, the light source is connected to the first coupler, the first coupler is connected to the thermostat, the thermostat is connected to the distributed optical fiber sensor, the first coupler is also connected to the second coupler, the second coupler is also connected to the long-wave filter and the short-wave filter, the two filters are simultaneously connected to the detector, the detector uses the photoelectric effect to convert the optical signal into an electrical signal, the detector is connected to the data processing device, and the data processing device is simultaneously connected to the alarm device and the display device. The first coupler is used to synthesize Reman light, and the second coupler is used to extract stokes and anti-stokes. The two couplers are used to realize the device for transmitting optical signals between optical fibers, and can couple, distribute and regulate optical signals from different optical fibers to meet the optical communication and optical sensing requirements in different application scenarios.

[0065] As one of the preferred embodiments, the data processing device further comprises a control manager: the control manager is used to control and adjust the temperature of the thermostat in the distributed optical fiber sensor so as to enable the sensor to achieve the best working state.

[0066] The working process of the device is:

[0067] The light source emits light through the coupler and the constant temperature box, and is transmitted to the transmission optical fiber of the monitoring point. The light is reflected back through the transmission optical fiber, passes through the constant temperature box and the coupler, passes through the long-wave filter and the short-wave filter, and the data is transmitted to the detector. The data acquisition and processing unit collects the light intensity signal passing through the long-wave filter and the short-wave filter, and calculates the temperature of the area where the sensor is located.

[0068] The following is further described in conjunction with specific embodiments:

[0069] Example 1

[0070] For example: select 7 sensors that are 2.2m away from the bottom of the tank and surround the tank. The temperatures measured at time s are 17.318, 17.253, 17.253, 17.624, 17.249, 17.253, and 17.446, and the temperatures measured at time s+1 are 17.852, 17.253, 17.253, 17.624, 17.249, 17.253, and 17.446. Set the temperature difference threshold to 0.2 degrees Celsius, and calculate from the temperature difference-position fitting function that the position error exceeds 5mm. At the same time, the temperature difference error exceeds 0.2 degrees Celsius, and it is determined that the first point has sent a leak. Substitute 17.852 into the temperature difference-position fitting function, and the calculated leak position is 2.0m from the bottom of the tank.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A tank leakage monitoring method, characterized in that: The following steps are involved: Step 1, collecting the temperature of a monitoring point, wherein the monitoring point is arranged on the tank body of the oil storage tank (1); Step 2, inputting the temperature range to which the temperature of the monitoring point belongs into the corresponding temperature-position fitting function calculation formula to obtain the position of the monitoring point in the oil storage tank (1); obtaining the position values ​​of the same monitoring point at two moments, and subtracting the two position values ​​to obtain the position difference; in the temperature-position fitting function, different temperature ranges correspond to different calculation formulas; Step 3, compare the position difference and the error threshold. If the position difference exceeds the error threshold, the monitoring point is considered to be leaking, and the position of the leak point is determined based on the position value measured at the second moment.

2. A tank leakage monitoring method according to claim 1, characterized in that: The monitoring points are distributed in a grid-like pattern on the tank body.

3. A tank leakage monitoring method according to claim 2, characterized in that: Through the point distribution in the form of a grid, a temperature matrix is ​​obtained; each element in the temperature matrix corresponds to the position of a monitoring point on the tank body.

4. A tank leakage monitoring method according to claim 1, characterized in that: The temperature of the monitoring point is obtained by measuring the light intensity signal of the sensing optical fiber (2).

5. A tank leakage monitoring method according to claim 4, characterized in that: The formula for calculating the temperature of the monitoring point through the light intensity signal is: Where a is the temperature correlation coefficient, h is the Planck constant, c is the speed of light in vacuum, v is the Raman shift, k is the Boltzmann constant, and k t Indicates the thermostat adjustment coefficient, I a Represents the Anti-Stokes light intensity, I s Indicates the intensity of Stokes light.

6. A tank leakage monitoring method according to claim 1, characterized in that: The temperature-position fitting function is: Where y represents the temperature t ij The fitting distance from the point to the bottom of the tank, A1-A4, B1-B4, C1-C4, D1-D4 and E1-E4 represent constant coefficients, A1=4.40873, B1=37.667901, C1=117.20747, D1=1621.70629, E1=-109,693.1109, A2=2.0356, B2=32.83815, C2=143.82778, D2=1846 .13962, E2=-86, 138.3242, A3=1.65412, B3=87.70538, C3=172.46875, D3=1516.61181, E3=-49 97341.38611, A4=3.77297, B4=52.11203, C4=406.08675, D4=3551.06672, E4=-8202960.53222.

7. A tank leakage monitoring method according to claim 1, characterized in that: In step 3, the error threshold is 5 mm.

8. A tank leakage monitoring system for implementing the monitoring method of claim 1, characterized in that: include: Data acquisition equipment, used to collect the temperature of the monitoring point; The data processing device is used to input the temperature range to which the temperature of the monitoring point belongs into the corresponding temperature-position fitting function to obtain the position of the monitoring point in the oil storage tank (1); obtain the position values ​​of the same monitoring point at two moments, subtract the two position values ​​from each other, and obtain the position difference; compare the position difference with an error threshold, and if the position difference exceeds the error threshold, determine that the monitoring point is leaking, and determine the position of the leaking point based on the position value measured at the second moment.

9. The tank leakage monitoring system according to claim 8, characterized in that: It also includes a display device and an alarm device, and both the display device and the alarm device are connected to the data processing device.

10. The tank leakage monitoring system according to claim 8, characterized in that: The data acquisition device includes a light source, a constant temperature box, a coupler, a long-wave filter, a short-wave filter and a detector; the light source is connected to the coupler, the coupler is connected to the constant temperature box, and the constant temperature box is connected to the distributed optical fiber sensor; the coupler is connected to the long-wave filter and the short-wave filter at the same time, the long-wave filter and the short-wave filter are both connected to the detector, and the detector is connected to the data processing device.

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