CN-121409362-B - Storage tank liquid level measurement method

CN121409362BCN 121409362 BCN121409362 BCN 121409362BCN-121409362-B

Abstract

The invention relates to the technical field of liquid level measurement of storage tanks, in particular to a liquid level measurement method of a storage tank. According to the invention, temperature correction is carried out on the standard relative dielectric constant of electromagnetic waves in each gas component through collected reference temperature in the tank, the real-time propagation wave speed of the electromagnetic waves is calculated according to the volume ratio of each gas component, the liquid level overhead height from the tank top to the liquid level is obtained according to the real-time propagation wave speed collection, the corrected accumulation thickness of sediment in the tank is obtained according to disturbance data of recent crude oil disturbance operation, the initial liquid level height of the oil storage tank is calculated according to the designed internal height of the oil storage tank, the internal oil capacity of the oil storage tank is calculated according to the initial liquid level height, the micro-variation correction is carried out on the oil capacity in the tank according to the micro-variation influence degree of the tank body corresponding to the reference temperature, and the final oil storage capacity is output, so that the final oil storage capacity measurement result is more fit with the actual value, and the reliability of trade settlement and production scheduling is improved.

Inventors

CUI GUILIANG
LI HONGLEI
CHEN HUI
YAO JIAYAN
ZHANG TONG

Assignees

青岛澳邦量器有限责任公司

Dates

Publication Date: 20260508
Application Date: 20251226

Claims (9)

1. A method of tank level measurement, comprising: Acquiring temperatures and gas component contents at different positions in an oil storage tank through a sensor group arranged in the oil storage tank, and determining reference temperature and reference gas component contents in the oil storage tank; Correcting the standard relative dielectric constant of the electromagnetic wave in each gas component according to the reference temperature, and calculating the actual propagation wave velocity of the electromagnetic wave in the tank by combining the volume ratio of each gas component in the content of the reference gas component; transmitting electromagnetic waves with different angles to the liquid surface according to actual wave transmission speed by a radar liquid level meter arranged on the tank top, collecting echo time of the electromagnetic waves with different angles, and analyzing the liquid level overhead height from the tank top to the liquid surface; according to the real-time stacking thickness distribution of the sediment in the tank, the corrected stacking thickness of the sediment in the tank is output by combining the disturbance data of the recent crude oil disturbance operation, and the initial liquid level height of the oil storage tank is calculated by combining the designed internal height of the oil storage tank; the corrected stacking thickness mode of the sediment in the output tank is as follows: Collecting initial stacking thicknesses of sediments in different areas in the bottom of the oil storage tank in real time through an ultrasonic detection device, and forming a real-time stacking thickness distribution set of the sediments in the tank; extracting initial liquid level, input oil quantity and interval duration of the recent crude oil flow disturbance operation from a storage tank operation database, and matching deposit thickness correction values of the deposits in different areas based on a constructed deposit thickness time variation relation; Correcting the real-time stacking thickness distribution set based on stacking thickness correction values of the sediments in different areas to obtain a corrected stacking thickness distribution set; The thickness uniformity judgment is carried out on the corrected stacking thickness distribution set, when the thickness is uniform, the thickness average value in the corrected stacking thickness distribution set is taken as the corrected stacking thickness, and when the thickness is nonuniform, the maximum thickness and the minimum thickness in the corrected stacking thickness distribution set are screened, and the average value is taken as the corrected stacking thickness; and calculating the oil capacity in the oil storage tank according to the initial liquid level height, extracting historical liquid level difference data of the oil storage tank at different temperatures, determining the micro-variation influence degree of the tank body corresponding to the reference temperature, performing micro-variation correction on the oil capacity in the tank, and outputting the final oil storage capacity.
2. The method for measuring the liquid level of a storage tank according to claim 1, wherein the reference temperature and the reference gas component content in the tank are determined by: the temperature and gas component content of different positions in the oil storage tank collected by the sensor group are classified according to the collection height, and a temperature subset and a gas component content subset corresponding to each height layer are obtained; Performing outlier detection on the corresponding characteristic values in each subset, removing abnormal characteristic values exceeding the distribution characteristic range, and reserving effective temperature and effective gas component content; taking the average value of all effective temperatures and the effective gas component contents in each height layer as the corresponding interlayer temperature and interlayer gas component content; And carrying out weighted summation on the interlayer temperature and the interlayer gas component content of each height layer based on the temperature associated weight and the gas component content weight corresponding to each height layer in the oil storage tank to obtain the reference temperature and the reference gas component content.
3. The method for measuring the liquid level of a storage tank according to claim 1, wherein the actual propagation wave velocity is obtained as follows: Extracting standard relative dielectric constants of radar electromagnetic waves in a standard state in each gas component from a gas physical property database based on the content of the reference gas component; Comparing the standard thermodynamic temperature corresponding to the standard state with the reference temperature, carrying out fusion calculation on the ratio of the standard thermodynamic temperature corresponding to the standard state and the reference temperature, and determining the corrected relative dielectric constant of each gas component at the reference temperature; obtaining the volume ratio of each gas component based on the content of the reference gas component, and analyzing the equivalent relative dielectric constant corresponding to the electromagnetic wave by combining the corrected relative dielectric constant of each gas component at the reference temperature; Substituting the equivalent relative dielectric constant corresponding to the electromagnetic wave into an electromagnetic wave speed standard formula, and outputting the actual propagation wave speed of the electromagnetic wave in the tank.
4. The method for measuring the liquid level of a storage tank according to claim 3, wherein the step of analyzing the liquid level overhead height from the top of the tank to the liquid level is as follows: Based on the echo time of electromagnetic waves at different angles, calculating the propagation distance of the electromagnetic waves at each angle by combining the association relation between the propagation distance of the electromagnetic waves and the actual propagation wave speed and the echo time; and carrying out angle correction on the propagation distance of the electromagnetic wave under each angle to obtain the linear propagation distance of the electromagnetic wave under each angle, and taking the average value of the linear propagation distance as the liquid level overhead height from the tank top to the liquid level.
5. The method for measuring the liquid level of a storage tank according to claim 1, wherein the time-varying relation of the deposit accumulation thickness is constructed by the following steps: The method comprises the steps of calling input oil quantity and initial liquid level in each crude oil flow disturbance operation from a storage tank operation database, and counting each crude oil flow disturbance operation corresponding to each input oil quantity in each initial liquid level interval; Extracting the stacking thickness change time sequence of the sediments in different areas in the tank after each crude oil flow disturbance operation based on the initial thickness of the sediments in different areas in the tank before each crude oil flow disturbance operation, and obtaining the stacking thickness mode of the sediments in different areas in the tank in each time period; and linearly fitting the accumulation thickness modes of each duration, constructing a relation of the accumulation thickness of the sediment with the time change, and counting the relation of the accumulation thickness of the sediment in different areas of each input oil quantity in each initial liquid level interval.
6. The method for measuring the liquid level of a storage tank according to claim 1, wherein the process of calculating the initial liquid level of the storage tank is as follows: and obtaining the designed internal height of the oil storage tank from the design parameters of the oil storage tank, comparing the designed internal height with the liquid level overhead height from the tank top to the liquid level to obtain the theoretical liquid level height from the tank bottom to the liquid level, and taking the difference between the theoretical liquid level height and the corrected accumulation thickness of the sediment in the tank as the initial liquid level height of the oil storage tank.
7. The method for measuring the liquid level of a storage tank according to claim 1, wherein the calculation mode of the oil capacity in the storage tank is as follows: The design internal sectional area of the oil storage tank is obtained from the design parameters of the oil storage tank, the initial liquid level height of the oil storage tank is multiplied by the design internal sectional area, and the result of the multiplication is used as the internal oil capacity of the oil storage tank.
8. The method for measuring the liquid level of a storage tank according to claim 7, wherein the method for determining the degree of influence of micro-variation of the tank body corresponding to the reference temperature is as follows: Extracting the temperature in the tank, the initial liquid level height and the real-time oil storage capacity in the oil storage tank corresponding to each time of history liquid level measurement record, and combining the real-time oil storage capacity with the designed internal sectional area to obtain the theoretical liquid level height of the real-time oil storage capacity; Performing deviation analysis on the initial liquid level height and the theoretical liquid level height in each historical liquid level measurement record to obtain a liquid level height deviation rate, and taking the liquid level height deviation rate as the micro-variation influence degree of the tank body; Counting the micro-change influence degree of the tank body corresponding to each time of historical liquid level measurement record of the temperature in each tank, and obtaining the micro-change influence degree of the tank body corresponding to the temperature in each tank through average value calculation; Taking the temperature as an independent variable, taking the micro-variation influence degree of the tank body as a dependent variable, and adopting least square fitting to obtain an association equation of the temperature and the micro-variation influence degree of the tank body; and inputting the reference temperature in the tank into the fitted correlation equation, and outputting the corresponding micro-variation influence degree of the tank.
9. The method for measuring the liquid level of a storage tank according to claim 8, wherein the output final oil storage capacity is as follows: and calculating the product of the oil capacity in the oil storage tank and the micro-variation influence degree of the tank body corresponding to the reference temperature to obtain an oil capacity micro-variation correction value, and calculating the oil capacity micro-variation correction value and the oil capacity in the oil storage tank in an accumulated manner to output the final oil storage capacity.

Description

Storage tank liquid level measurement method Technical Field The invention relates to the technical field of liquid level measurement of storage tanks, in particular to a liquid level measurement method of a storage tank. Background Along with the continuous improvement of the intelligent level in the petrochemical industry, the liquid level measurement of the storage tank is used as a core monitoring link in the crude oil storage and transportation process, and the precision and the reliability of the liquid level measurement are directly related to the accuracy of inventory management and trade settlement. The internal environment of the storage tank is complex, the liquid level measurement is interfered by various dynamic factors, and how to realize accurate measurement under complex working conditions is a current technical difficulty. In the prior art, chinese patent publication No. CN120467470A discloses a liquid level monitoring method and a liquid level monitoring system based on a radar liquid level meter, and the method and the system judge whether the dielectric constant is abnormal or not by matching the current temperature of substances stored in a target storage tank with the dielectric constant, simultaneously evaluate key obstacles in the target tank in a multi-dimensional manner, and identify foam or steam interference through multiple verification, so that measurement errors are reduced. The invention discloses a method, a device and a system for automatically measuring the liquid level of a storage tank, which are disclosed in Chinese patent publication No. CN118960903B, by acquiring echo signals of a guided wave radar liquid level meter, and acquiring the distance from the guided wave radar to the liquid level and the distance from the guided wave radar to the bottom of the liquid storage tank, and identifying a hanging material signal section, calculating a corresponding wave speed attenuation weight and electromagnetic wave speed, constructing a hanging material area speed vector, correcting a liquid level measurement result, and reducing errors caused by hanging materials. Although the prior art optimizes the liquid level measurement precision to a certain extent, the prior art only focuses on the single influence of temperature on the dielectric constant of a storage medium, corrects the medium parameters in a temperature matching mode, but does not consider the coupling effect of mixed gas components in a tank on the propagation speed of electromagnetic waves, so that the calculation deviation of the propagation wave speed of the electromagnetic waves in the gas environment in the tank is caused, the deviation of the measurement of the height from the tank top to the liquid level is caused, and the subsequent liquid level and capacity analysis precision is influenced. (2) The prior art focuses on solving the problem of hanging materials of the guided wave radar, but does not fully consider the long-term accumulation of tank bottom sediment and the influence of thickness dynamic change caused by disturbance such as crude oil input on a liquid level reference surface, so that the actual liquid level height calculation from the tank bottom to the liquid level has errors, the effective oil storage space in the tank cannot be accurately reflected, and systematic deviation exists in liquid level height measurement. (3) The prior art ignores the micro-deformation effect of the metal structure of the tank body caused by the change of the temperature field, and only directly calculates the capacity through the product of the liquid level height and the sectional area of the tank body, and the temperature change can cause the tank body to generate micro deformation, so that the actual sectional area is different from the designed sectional area, and finally the deviation between the oil storage capacity measurement result and the actual value is larger, thereby affecting the accuracy of trade settlement and production scheduling. Disclosure of Invention In order to solve the problems in the prior art, the invention provides a liquid level measuring method for a storage tank, and the technical scheme adopted by the invention for solving the technical problems is as follows: S1, acquiring temperatures and gas component contents at different positions in an oil storage tank through a sensor group arranged in the oil storage tank, and determining reference temperature and reference gas component contents in the tank. S2, correcting the standard relative dielectric constants of the electromagnetic waves in the gas components according to the reference temperature, and calculating the actual propagation wave velocity of the electromagnetic waves in the tank by combining the volume ratio of the gas components in the content of the reference gas components. S3, transmitting electromagnetic waves of different angles to the liquid surface according to actual wave transmission speed through a radar liqu