Constant pressure control system for gas conveying pipeline

Abstract

The invention discloses a gas conveying pipeline constant pressure control system, which relates to the technical field of pipeline constant pressure control, and comprises a gas conveying pipeline analysis module, a pipeline transmission delay evaluation module, a gas safety influence evaluation module, a pressure change trend analysis module, a pressure control trigger condition evaluation module and a constant pressure control evaluation module, in the constant pressure control process of the gas conveying pipeline, various types of information are obtained through the gas conveying pipeline analysis module, pressure wave correlation parameters are analyzed, the propagation duration, the safety risk index and the pressure dynamic change trend index are calculated by integrating the multiple parameters through all the evaluation modules, and the constant pressure control requirements and measures of the monitoring points are comprehensively evaluated. The gas state change in the pipeline can be accurately mastered, the constant-pressure control operation is scientifically decided, the gas conveying stability and safety are guaranteed, the accident risks of leakage, explosion and the like caused by out-of-control pressure are reduced, and the overall reliability and safety of a gas conveying system are improved.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline constant pressure control, and in particular to a gas transmission pipeline constant pressure control system. Background Art

[0002] With the widespread application of gas in industries and other fields, gas transportation safety is of vital importance. Traditional gas pipelines are prone to leakage, explosion and other accidents due to pressure fluctuations. In order to ensure stable and safe operation, there is an urgent need for precise pressure control of gas pipelines. A gas pipeline constant pressure control system aims to achieve efficient constant pressure control through multi-parameter monitoring and analysis, and improve the safety and reliability of gas transportation.

[0003] At present, the constant pressure control system of gas transmission pipelines may have the following problems: 1. At present, in the process of constant pressure control of gas transmission pipelines, there is a lack of accurate perception and analysis capabilities of changes in the micro-environment in the pipeline. For example, when analyzing the correlation parameters of gas pressure waves, the local roughness coefficient is not obtained by ultrasonic measurement and the dynamic viscosity is not obtained by viscosity meter. The gas bulk elastic modulus cannot be accurately calculated, which is not conducive to an in-depth understanding of the subtle characteristics of gas pressure propagation in the pipeline, and will lead to deviations in the calculation of the pressure wave propagation time, which will lead to errors in the timing and intensity of the entire constant pressure control.

[0004] 2. Traditional constant pressure control of gas transmission pipelines lacks a comprehensive and dynamic evaluation mechanism for multiple factors, lacks an assessment of the safety risks of gas transmission pressure, and lacks weighted calculation of multiple factors such as the rate of change of gas flame propagation speed, the degree of proximity to the explosion limit, and the change value of the adiabatic index. It only focuses on one or two indicators, which is not conducive to comprehensive control of the safety risk status in the gas transportation process, and will lead to inaccurate and in-time assessment of safety risks. For example, it will underestimate the danger level of gas in the pipeline, and fail to take effective constant pressure control and other safety measures in time when the safety risk is already high, thus putting the pipeline system in an extremely dangerous situation and posing a huge threat to the safety of personnel life and property.

[0005] 3. In the past, constant pressure control of gas transmission pipelines often lacked in-depth exploration of the intrinsic connection between changes in gas properties and pressure change trends. When calculating the dynamic change trend index of gas pipeline pressure, if the analysis of the change rate of gas impurity content and concentration and their mutual cross-influence is ignored, simply monitoring the change in pressure values ​​is not conducive to predicting abnormal pressure fluctuations in advance, and will result in passive response to pressure changes. For example, when the gas impurity content gradually increases and begins to affect the pressure stability, due to failure to detect and deal with it in time, the pressure fluctuations continue to intensify, and eventually exceed the pipeline's tolerance range, thereby causing pipeline rupture or other safety accidents, seriously affecting the normal operation and reliability of the gas transmission system. Summary of the invention

[0006] The purpose of the present invention is to provide a constant pressure control system for a gas transmission pipeline, which solves the problems existing in the background technology.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a constant pressure control system for a gas transmission pipeline, including: a gas transmission pipeline analysis module, used to obtain the corresponding gas transmission pipeline information when the gas is transported in the transmission pipeline, set various monitoring points in the gas transmission pipeline, and then analyze the pressure wave correlation parameters corresponding to each monitoring point in the gas transmission pipeline.

[0008] The pipeline transmission delay evaluation module is used to calculate the propagation time of the pressure wave between each monitoring point based on the pressure wave correlation parameters corresponding to the gas transmission in the transmission pipeline.

[0009] The gas safety impact assessment module is used to obtain the safety impact parameters corresponding to each monitoring point in the gas transmission pipeline, and then calculate the gas transmission pressure safety risk index corresponding to each monitoring point.

[0010] The pressure change trend analysis module is used to obtain the gas change parameters corresponding to each monitoring point in the gas transmission pipeline, and then calculate the dynamic change trend index of the gas pipeline pressure corresponding to each monitoring point within a set time period.

[0011] The pressure control trigger condition evaluation module is used to evaluate whether constant pressure control operation is required at each monitoring point corresponding to the gas transmission pipeline based on the propagation time of the pressure wave between each monitoring point, the gas transmission pressure safety risk index corresponding to each monitoring point, and the dynamic change trend index of the gas pipeline pressure corresponding to the set time period.

[0012] The constant pressure control evaluation module is used to evaluate the control measures of the constant pressure control when a certain monitoring point corresponding to the gas transmission pipeline needs to perform a constant pressure control operation.

[0013] The beneficial effects of the present invention are as follows: 1. A constant pressure control system for a gas transmission pipeline provided by the present invention, in the process of obtaining information on the gas transmission pipeline, comprehensively and accurately obtains key information such as pipeline length, inner diameter, wall thickness and material by combining design drawings and on-site measurements, which is conducive to laying a solid foundation for subsequent analysis and calculation of various aspects such as pressure wave propagation characteristics. For example, accurate pipeline inner diameter and wall thickness data are indispensable in calculating the gas bulk elastic modulus, providing initial accurate data support for the accurate evaluation and control of gas pressure by the pipeline constant pressure control system.

[0014] 2. When analyzing gas pressure wave related parameters, the embodiment of the present invention obtains the gas bulk elastic modulus through a specific calculation formula, and utilizes advanced measurement technology and scientific calculation methods, which is conducive to a deep understanding of the gas pressure propagation mechanism in the pipeline, and a more detailed analysis of the influence of the gas's own properties and the condition of the inner wall of the pipeline when the pressure wave propagates in the pipeline, thereby providing a key basis for the subsequent precise control of pressure.

[0015] 3. In the process of calculating the propagation time of the pressure wave between each monitoring point, the embodiment of the present invention first calculates the propagation speed according to the relevant formula, and then calculates the propagation time in combination with the distance between the monitoring points. The calculation method is gradually derived, which is conducive to the system to accurately grasp the transmission rhythm of the gas pressure in the pipeline. Whether it is for pressure monitoring under normal operating conditions or for quickly locating the source of pressure changes when abnormal situations occur, it provides reliable data support, can promptly detect and take corresponding measures at the early stage of pressure fluctuations, and effectively ensure the stability and safety of gas transportation.

[0016] 4. In the process of evaluating the safety risk index of gas transportation pressure, the embodiment of the present invention comprehensively considers multiple factors such as the change rate of gas flame propagation speed, the degree of proximity to the explosion limit and the change value of the adiabatic index through a specific formula, which is conducive to a comprehensive and systematic evaluation of the safety risk status of gas in the pipeline transportation process. It no longer relies solely on a certain indicator for judgment, but a multi-dimensional comprehensive analysis, making the safety risk assessment more scientific, comprehensive and accurate.

[0017] 5. When calculating the dynamic change trend index of the gas pipeline pressure, the embodiment of the present invention calculates the influence value based on the change rate of the gas impurity content and the concentration change rate and comprehensively obtains the trend index, which is conducive to predicting the change trend of the gas pressure in advance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the system structure connection of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figure 1 As shown, the present invention provides a constant pressure control system for a gas transmission pipeline, the method comprising: a gas transmission pipeline analysis module, a pipeline transmission delay evaluation module, a gas safety impact evaluation module, a pressure change trend analysis module, a pressure control trigger condition evaluation module, a constant pressure control evaluation module and a database.

[0022] The gas transmission pipeline analysis module is respectively connected to the pipeline transmission delay assessment module and the gas safety impact assessment module, the pipeline transmission delay assessment module is connected to the database, the gas safety impact assessment module is connected to the pressure change trend analysis module, and the pressure control trigger condition assessment module is respectively connected to the pressure change trend analysis module, the constant pressure control assessment module and the database.

[0023] The gas transmission pipeline analysis module is used to obtain the gas transmission pipeline information corresponding to the gas transmission pipeline when the gas is transported in the transmission pipeline, set various monitoring points in the gas transmission pipeline, and then analyze the pressure wave correlation parameters corresponding to each monitoring point in the gas transmission pipeline.

[0024] It should be noted that the setting of each monitoring point is based on factors such as the length of the gas transmission pipeline, topography, pipeline connection locations, and areas where accidents have occurred frequently in the past. For example, on a gas transmission pipeline with a length of 5 kilometers that passes through a mountainous area, the first monitoring point is set at 0.5 kilometers from the starting end of the pipeline. Because the pipeline enters the transition zone from a flat area into a mountainous area, changes in topography will affect the pressure wave. A monitoring point is set at the bottom of the valley at 2 kilometers. The low-lying terrain is prone to accumulation of impurities and is greatly affected by geological subsidence. A monitoring point is set at the pipeline connection branch at 3.5 kilometers.

[0025] In a specific embodiment, the analysis of the pressure wave correlation parameters corresponding to the gas in the transmission pipeline is performed as follows: the local roughness coefficient of each monitoring point corresponding to the gas transmission pipeline is measured by ultrasonic measurement, recorded as ki, and the dynamic viscosity of the gas at each monitoring point is measured by a viscosity measuring instrument, recorded as gi, so as to calculate the following formula: The gas bulk elastic modulus Ei corresponding to each monitoring point is obtained, where i is the number of each monitoring point corresponding to the gas transmission pipeline, i=1, 2,..., n, n is the total number of monitoring points, and n is a positive integer, wherein di and hi represent the inner diameter and wall thickness of the gas transmission pipeline corresponding to each monitoring point, respectively, and E′ represents the original elastic modulus corresponding to the gas transmission pipeline when it is put into use.

[0026] It should be noted that it is an existing technology to measure the local roughness coefficient of each monitoring point corresponding to the gas transmission pipeline by ultrasonic measurement method and the dynamic viscosity of the gas at each monitoring point by viscosity measuring instrument, which will not be elaborated here. Dynamic viscosity refers to the measurement of the internal friction force when the adjacent fluid layers inside the gas are in relative motion when the gas is in a flowing state. The dynamic viscosity is related to pressure. In fluids such as gas, an increase in pressure will lead to a decrease in the molecular distance and an increase in the intermolecular force, which will increase the dynamic viscosity, thereby affecting the fluidity and pressure wave propagation of the gas in the transmission pipeline.

[0027] It should also be noted that the application background is that when the pressure monitoring system in the pipeline issues an abnormal alarm, the pressure of the transmission pipeline is evaluated immediately, or a fixed time period is set to evaluate the pressure of the gas transmission pipeline. For example, for some high-risk gas transmission pipelines, a comprehensive pressure assessment is performed every day or every week. The gas bulk elastic modulus refers to a physical quantity that indicates the resistance of the unit volume of gas in the transmission pipeline to the relative change in volume when the pressure changes. The original elastic modulus corresponding to the gas transmission pipeline when it is put into use is obtained from the database.

[0028] The pipeline transmission delay evaluation module is used to calculate the propagation time of the pressure wave between each monitoring point based on the pressure wave correlation parameters corresponding to the gas transmission in the transmission pipeline.

[0029] In a specific embodiment, the propagation time of the pressure wave between the monitoring points is obtained by calculation, and the specific calculation process is as follows: by the calculation formula: The propagation velocity vi of the pressure wave corresponding to the ith monitoring point in the gas transmission pipeline is obtained, where ci and ρi represent the specific heat ratio and gas density of the gas at the ith monitoring point in the gas transmission pipeline, respectively.

[0030] According to the length of the gas transmission pipeline and the location of each monitoring point, the corresponding distance between the monitoring points is obtained, which is denoted as li. Li represents the distance between the i-th monitoring point and the i-1-th monitoring point. The calculation formula is: The corresponding propagation time Ti of the pressure wave from the i-th monitoring point to the i-1-th monitoring point is obtained.

[0031] It should be noted that the corresponding number "4" in the calculation formula of the propagation velocity means that after removing "4", the correction effect of the viscous force on the pressure wave propagation velocity will be reduced compared with the original formula. In actual situations, if the dynamic viscosity of the gas is large, removing "4" will make the calculated pressure wave propagation velocity larger than the actual velocity after considering the viscosity effect. For example, when gi is large, according to the original formula, the viscous force will have a greater "deceleration" effect on the velocity, and after removing "4", the "deceleration" effect will be reduced.

[0032] It should also be noted that the gas is a mixed gas composed of multiple gases such as methane. The gas specific heat ratio corresponding to each monitoring point is calculated according to the specific heat ratio of the gases that make up the multiple gases and the theoretical calculation rules of the mixed gas. The gas density corresponding to each monitoring point is calculated according to the ideal gas state equation based on the pressure, temperature and composition of the gas. The calculation process is existing technology and will not be elaborated here.

[0033] When analyzing the gas pressure wave correlation parameters, the embodiment of the present invention obtains the gas bulk elastic modulus through a specific calculation formula, and utilizes advanced measurement technology and scientific calculation methods, which is conducive to a deep understanding of the gas pressure propagation mechanism in the pipeline, and a more detailed analysis of the influence of the gas's own properties and the condition of the inner wall of the pipeline when the pressure wave propagates in the pipeline, thereby providing a key basis for the subsequent precise control of pressure.

[0034] The gas safety impact assessment module is used to obtain the safety impact parameters corresponding to each monitoring point in the gas transmission pipeline, and then calculate the gas transmission pressure safety risk index corresponding to each monitoring point.

[0035] In a specific embodiment, the gas transmission pressure safety risk index corresponding to each monitoring point is calculated, and the specific calculation process is as follows: the historical safety impact parameters corresponding to the historical gas transmission pipeline are obtained from the database, and then the maximum gas flame propagation speed change rate, the maximum gas explosion limit approach degree, the maximum gas adiabatic index change value, the minimum gas flame propagation speed change rate, the minimum gas explosion limit approach degree and the minimum gas adiabatic index change value are selected from the historical safety impact parameters, and are respectively recorded as HV max , BZ max , JK max 、HV min , BZ min and JK min .

[0036] By calculation formula:

[0037] The gas transmission pressure safety risk index PSi corresponding to each monitoring point is obtained, where HVi, BZi, and JKi represent the gas flame propagation velocity change rate, the degree of proximity to the gas explosion limit, and the gas adiabatic index change value corresponding to the i-th monitoring point, respectively; η1, η2, and η3 are the weight factors corresponding to the set gas flame propagation velocity change rate, the weight factors corresponding to the degree of proximity to the gas explosion limit, and the weight factors corresponding to the gas adiabatic index change value, respectively.

[0038] It should be noted that the values ​​of η1, η2, and η3 are all greater than 0 and less than 1, and the process of setting the weight factor is as follows: for example, for a gas transmission pipeline, after long-term monitoring, it is determined that the change rate of the gas flame propagation speed has a relatively small impact on the overall safety risk, then η1 is set to 0.2, and the degree of proximity to the gas explosion limit is extremely critical, then η2 is set to 0.6, because once the gas concentration approaches the explosion limit, the risk factor rises sharply, and the change value of the gas adiabatic index has an impact on the energy transfer and the intensity of the reaction, then η3 is set to 0.2.

[0039] In the process of calculating the propagation time of the pressure wave between each monitoring point, the embodiment of the present invention first calculates the propagation speed according to the relevant formula, and then calculates the propagation time in combination with the distance between the monitoring points. The step-by-step calculation method is conducive to the system to accurately grasp the transmission rhythm of the gas pressure in the pipeline. Whether it is for pressure monitoring under normal operating conditions or for quickly locating the source of pressure changes when abnormal situations occur, it provides reliable data support, can promptly detect and take corresponding measures at the early stage of pressure fluctuations, and effectively ensure the stability and safety of gas transportation.

[0040] The pressure change trend analysis module is used to obtain the gas change parameters corresponding to each monitoring point in the gas transmission pipeline, and then calculate the dynamic change trend index of the gas pipeline pressure corresponding to each monitoring point within the set time period.

[0041] In a specific embodiment, the gas transportation pipeline information corresponding to the gas being transported in the transportation pipeline is obtained by the following specific process: the gas transportation pipeline information is obtained from the design drawings of the gas transportation pipeline and on-site measurements, and the gas transportation pipeline information includes the pipeline length, pipeline inner diameter, pipeline wall thickness and pipeline material. The pressure influencing parameters include gas density, gas bulk elastic modulus and gas temperature. The safety influencing parameters include the change rate of gas flame propagation speed, the degree of proximity to the gas explosion limit and the change value of the gas adiabatic index. The gas property change parameters include the change rate of gas impurity content and the change rate of gas concentration.

[0042] It should be noted that the rate of change of flame propagation speed is affected by pressure. Pressure changes will change the distance between gas molecules and the reaction activity. Pressure changes will change the gas density, thereby affecting the degree of proximity to the gas explosion limit. Increased pressure will make the gas closer to the explosion limit. Changes in pressure will lead to different adiabatic compression or expansion processes of the gas, causing the adiabatic index to change.

[0043] It should also be noted that the rate of change of the gas flame propagation speed is obtained by simulating the gas combustion environment in the experimental device, changing the gas concentration, temperature, pressure and other conditions, recording the flame propagation speed with a high-speed camera and sensors, and comparing different time points to obtain the rate of change of the gas flame propagation speed. The degree of proximity to the gas explosion limit is obtained by first determining the explosion limit range of the main components of the gas, and then combining the on-site concentration sensor data to calculate the difference ratio with the explosion limit boundary. The change value of the adiabatic index of the gas is obtained by performing an adiabatic compression or expansion experiment on the gas in an insulated container, measuring the temperature and pressure changes, and calculating the change value of the adiabatic index of the gas.

[0044] For example, taking a monitoring point of a gas transmission pipeline as an example, for the flame propagation velocity change rate, if the flame propagation velocity is measured to be 3 meters per second at the monitoring point 1 at the starting end of the pipeline at time e, and after 5 seconds, the flame propagation velocity is measured to be 3.5 meters per second at the monitoring point 2 in the middle of the pipeline at time f=e+5, then the flame propagation velocity change rate is 3.5 minus 3, divided by 5, and then the flame propagation velocity change rate corresponding to the monitoring point 2 is obtained. The calculation process of the degree of proximity to the gas explosion limit and the change value of the adiabatic index of the gas is the same as the calculation process of the flame propagation velocity change rate, which will not be elaborated here.

[0045] In a specific embodiment, the calculation obtains the dynamic change trend index of the gas pipeline pressure corresponding to each monitoring point within a set time period. The specific calculation process is as follows: according to the gas impurity mass change rate and the gas concentration change rate corresponding to each monitoring point in the gas transmission pipeline, the influence value of the gas impurity mass change rate and the influence value of the gas concentration change rate corresponding to each monitoring point are calculated and recorded as Yi and Xi respectively, so as to be calculated by the calculation formula:

[0046] The dynamic change trend index PDi of the gas pipeline pressure corresponding to each monitoring point within the set time period is obtained, where κ1, κ2, and κ3 respectively represent the weight factor corresponding to the influence value of the set gas impurity content change rate, the weight factor corresponding to the influence value of the gas concentration change rate, and the weight factor of the cross-influence of the gas impurity content change rate and the gas concentration change rate on the dynamic change trend of pressure.

[0047] It should be noted that the values ​​of κ1, κ2, and κ3 are all greater than 0 and less than 1. The setting process of κ1, κ2, and κ3 is the same as the setting process of η1, η2, and η3, and will not be repeated here.

[0048] It should also be noted that, for example, when the change rate of gas impurity content and the change rate of gas concentration increase at the same time, the combined impact on the pressure change trend is not a simple linear addition, but will be synergistically enhanced, and then use Indicates the cross-effect of the change rate of gas impurity content and the change rate of gas concentration. When Yi and Xi are both less than the set standard value, the cross-effect term The contribution of Yi and Xi is relatively small, and when one or both of them are greater than the set standard value, the cross-influence term The contribution of will increase, and the speed of increase will accelerate with the increase of Yi and Xi.

[0049] In a specific embodiment, the calculation obtains the influence value of the gas impurity content change rate and the influence value of the gas concentration change rate corresponding to each monitoring point, and the specific calculation process is as follows: by the calculation formula: The influence value Yi of the gas impurity mass change rate corresponding to each monitoring point is obtained, where Zi is the gas impurity mass change rate corresponding to each monitoring point, Zmax is expressed as the reference value of the gas impurity mass change rate, and ζ is expressed as the sensitivity coefficient of the gas impurity mass change rate.

[0050] By calculation formula: The influence value Xi of the gas concentration change rate corresponding to each monitoring point is obtained, where Ni is the gas concentration change rate corresponding to each monitoring point, Nmax is represented as the reference value of the gas concentration change rate, ψ is represented as the sensitivity coefficient of the gas concentration change rate, and N′ is represented as the critical value of the gas concentration change rate.

[0051] It should be noted that, according to the start time point and end time point corresponding to the set time period, which are recorded as t1 and t2 respectively, the gas impurity content and gas concentration corresponding to each monitoring point are collected at the start time point and the end time point respectively, and then calculated by the formula:

[0052] The gas impurity content change rate Zi and gas concentration change rate Ni corresponding to each monitoring point are obtained respectively, c1i and c2i represent the gas impurity content of the i-th monitoring point at the start time point and the end time point respectively, b1i and b2i represent the gas concentration of the i-th monitoring point at the start time point and the end time point respectively.

[0053] In the process of evaluating the safety risk index of gas transportation pressure, the embodiment of the present invention comprehensively considers multiple factors such as the change rate of gas flame propagation speed, the degree of proximity to the explosion limit and the change value of the adiabatic index through a specific formula, which is conducive to a comprehensive and systematic evaluation of the safety risk status of gas in the pipeline transportation process. It no longer relies solely on a certain indicator for judgment, but a multi-dimensional comprehensive analysis, making the safety risk assessment more scientific, comprehensive and accurate.

[0054] The pressure control trigger condition evaluation module is used to evaluate whether constant pressure control operation is required at each monitoring point corresponding to the gas transmission pipeline based on the propagation time of the pressure wave between each monitoring point, the gas transmission pressure safety risk index corresponding to each monitoring point, and the dynamic change trend index of the gas pipeline pressure corresponding to the set time period.

[0055] In a specific embodiment, the evaluation of whether each monitoring point corresponding to the gas transmission pipeline needs to perform constant pressure control operation, the specific evaluation process is as follows: according to the gas transmission pressure safety risk index corresponding to each monitoring point and the corresponding gas pipeline pressure dynamic change trend index within a set time period, the comprehensive control coefficient of the gas pipeline pressure corresponding to each monitoring point is calculated, recorded as αi, and the result of whether each monitoring point corresponding to the gas transmission pipeline needs to perform constant pressure control operation is recorded as βi. When βi is 0, it indicates that the i-th monitoring point needs to perform constant pressure control operation, and when βi is 1, it indicates that the i-th monitoring point does not need to perform constant pressure control operation.

[0056] Through constant pressure control discriminant: The result βi of whether each monitoring point corresponding to the gas transmission pipeline needs to perform constant pressure control operation is obtained, where T′ represents the standard propagation time range interval corresponding to the set distance segment of the pressure wave, α′ represents the comprehensive control coefficient of the standard gas pipeline pressure, ∧ represents the relationship of and, and ∨ represents the relationship of or.

[0057] It should be noted that the standard propagation time range interval corresponding to the set distance segment of the pressure wave is obtained from the database.

[0058] In a specific embodiment, the calculation obtains the comprehensive control coefficient of the gas pipeline pressure at each monitoring point, and the specific calculation process is as follows: substitute the gas transportation pressure safety risk index corresponding to each monitoring point and the gas pipeline pressure dynamic change trend index corresponding to the set time period into the calculation formula: αi=PSi*λ1+PDi*λ2, and obtain the comprehensive control coefficient αi of the gas pipeline pressure corresponding to each monitoring point, wherein λ1 and λ2 are the weight factors corresponding to the set gas transportation pressure safety risk index and the weight factors corresponding to the gas pipeline pressure dynamic change trend index, respectively.

[0059] It should be noted that the values ​​of λ1 and λ2 are both greater than 0 and less than 1, and the setting process of λ1 and λ2 is the same as the setting process of η1, η2, and η3, which will not be repeated here.

[0060] When calculating the dynamic change trend index of the gas pipeline pressure, the embodiment of the present invention calculates the influence value based on the change rate of the gas impurity content and the concentration change rate and comprehensively obtains the trend index, which is conducive to predicting the change trend of the gas pressure in advance.

[0061] The constant pressure control evaluation module is used to evaluate the control measures of the constant pressure control when a certain monitoring point corresponding to the gas transmission pipeline needs to perform a constant pressure control operation.

[0062] In a specific embodiment, the control measures for evaluating constant pressure control are specifically processed as follows: according to the propagation time of the pressure wave between each monitoring point and the standard propagation time range interval corresponding to the pressure wave set distance segment, when the propagation time of the pressure wave at a certain monitoring point is greater than the upper limit value corresponding to the standard propagation time range interval corresponding to the pressure wave set distance segment, it indicates that the control measure of the constant pressure control is a pressure reduction operation; when the propagation time of the pressure wave at a certain monitoring point is less than the lower limit value corresponding to the standard propagation time range interval corresponding to the pressure wave set distance segment, it indicates that the control measure of the constant pressure control is a pressure increase operation.

[0063] It should be noted that the pressure reduction operation is aimed at the situation where the pressure wave propagation time is greater than the upper limit value of the standard propagation time range interval corresponding to the pressure wave setting distance segment. The gas source valve is adjusted to reduce the delivery volume, the temperature is adjusted to improve the gas properties, and the pressure regulating valve is fine-tuned to reduce the pressure and restore normal gas flow. The pressure increase operation is aimed at the situation where the pressure wave propagation time is less than the lower limit value of the standard propagation time range interval corresponding to the pressure wave setting distance segment. The leakage point is checked and repaired, the branch line is closed to reduce the leakage, the gas source output pressure is increased, and the boosting equipment is activated to increase the pressure.

[0064] The database is used to store historical safety impact parameters corresponding to historical gas transmission pipelines, and also stores the original elastic modulus corresponding to the gas transmission pipeline when it is put into use, and also stores the standard propagation time range interval corresponding to the set distance segment of the pressure wave.

[0065] A constant pressure control system for a gas transmission pipeline provided by the present invention, in the process of obtaining information on the gas transmission pipeline, comprehensively and accurately obtains key information such as pipeline length, inner diameter, wall thickness and material by combining design drawings and on-site measurements, which is conducive to laying a solid foundation for subsequent analysis and calculation of various aspects such as pressure wave propagation characteristics. For example, accurate pipeline inner diameter and wall thickness data are indispensable when calculating the gas bulk elastic modulus, providing initial accurate data support for the accurate evaluation and control of gas pressure by the pipeline constant pressure control system.

[0066] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined in this specification, they shall all fall within the protection scope of the present invention.

Claims

1. A gas transmission pipeline constant pressure control system, characterized in that: include: The gas transmission pipeline analysis module is used to obtain the gas transmission pipeline information corresponding to the gas transmission pipeline when the gas is transported in the transmission pipeline, set various monitoring points in the gas transmission pipeline, and then analyze the pressure wave correlation parameters corresponding to each monitoring point in the gas transmission pipeline; The pipeline transmission delay evaluation module is used to calculate the propagation time of the pressure wave between each monitoring point according to the pressure wave correlation parameters of the gas in the transmission pipeline; The gas safety impact assessment module is used to obtain the safety impact parameters corresponding to each monitoring point in the gas transmission pipeline, and then calculate the gas transmission pressure safety risk index corresponding to each monitoring point; The pressure change trend analysis module is used to obtain the gas change parameters corresponding to each monitoring point in the gas transmission pipeline, and then calculate the dynamic change trend index of the gas pipeline pressure corresponding to each monitoring point within the set time period; The pressure control trigger condition evaluation module is used to evaluate whether the monitoring points corresponding to the gas transmission pipeline need to perform constant pressure control operation according to the propagation time of the pressure wave between the monitoring points, the gas transmission pressure safety risk index corresponding to the monitoring points, and the dynamic change trend index of the gas pipeline pressure corresponding to the set time period; The constant pressure control evaluation module is used to evaluate the control measures of the constant pressure control when a certain monitoring point corresponding to the gas transmission pipeline needs to perform a constant pressure control operation.

2. A gas transmission pipeline constant pressure control system according to claim 1, characterized in that: The gas transportation pipeline information corresponding to the gas transportation in the transportation pipeline, the specific process is as follows: The gas transmission pipeline information is obtained from the design drawings of the gas transmission pipeline and on-site measurements. The gas transmission pipeline information includes pipeline length, pipeline inner diameter, pipeline wall thickness and pipeline material. The pressure influencing parameters include gas density, gas bulk elastic modulus and gas temperature. The safety influencing parameters include the change rate of gas flame propagation speed, the degree of proximity to the gas explosion limit and the change value of the gas adiabatic index. The gas property change parameters include the change rate of gas impurity content and the change rate of gas concentration.

3. A gas transmission pipeline constant pressure control system according to claim 2, characterized in that: The specific process of analyzing the pressure wave correlation parameters corresponding to the gas transport in the transport pipeline is as follows: The local roughness coefficient of each monitoring point of the gas transmission pipeline is measured by ultrasonic measurement method, recorded as ki, and the dynamic viscosity of the gas at each monitoring point is measured by viscosity measuring instrument, recorded as gi, so as to calculate the formula: The gas bulk elastic modulus Ei corresponding to each monitoring point is obtained, where i is the number of each monitoring point corresponding to the gas transmission pipeline, i=1, 2,..., n, n is the total number of monitoring points, and n is a positive integer, wherein di and hi represent the inner diameter and wall thickness of the gas transmission pipeline corresponding to each monitoring point, respectively, and E′ represents the original elastic modulus corresponding to the gas transmission pipeline when it is put into use.

4. A gas transmission pipeline constant pressure control system according to claim 3, characterized in that: The calculation obtains the propagation time of the pressure wave between each monitoring point. The specific calculation process is as follows: By calculation formula: The propagation velocity vi of the pressure wave corresponding to the ith monitoring point in the gas transmission pipeline is obtained, where ci and ρi represent the specific heat capacity ratio and gas density of the gas at the ith monitoring point in the gas transmission pipeline, respectively; According to the length of the gas transmission pipeline and the location of each monitoring point, the corresponding distance between the monitoring points is obtained, which is denoted as li. Li represents the distance between the i-th monitoring point and the i-1-th monitoring point. The calculation formula is: The corresponding propagation time Ti of the pressure wave from the i-th monitoring point to the i-1-th monitoring point is obtained.

5. A gas transmission pipeline constant pressure control system according to claim 4, characterized in that: The specific calculation process of the gas transmission pressure safety risk index corresponding to each monitoring point is as follows: The historical safety impact parameters corresponding to the historical gas transmission pipeline are obtained from the database, and then the maximum gas flame propagation speed change rate, the maximum gas explosion limit approach degree, the maximum gas adiabatic index change value, the minimum gas flame propagation speed change rate, the minimum gas explosion limit approach degree and the minimum gas adiabatic index change value are selected from the historical safety impact parameters, and are recorded as HV respectively. max , BZ max , JK max 、HV min , BZ min and JK min ; By calculation formula: The gas transmission pressure safety risk index PSi corresponding to each monitoring point is obtained, where HV i, BZ i, and JK i represent the gas flame propagation velocity change rate, the degree of proximity to the gas explosion limit, and the gas adiabatic index change value corresponding to the i-th monitoring point, respectively; η1, η2, and η3 are the weight factors corresponding to the set gas flame propagation velocity change rate, the weight factors corresponding to the degree of proximity to the gas explosion limit, and the weight factors corresponding to the gas adiabatic index change value, respectively.

6. A gas transmission pipeline constant pressure control system according to claim 5, characterized in that: The calculation obtains the gas pipeline pressure dynamic change trend index corresponding to each monitoring point within the set time period. The specific calculation process is as follows: According to the change rate of gas impurity content and gas concentration at each monitoring point in the gas pipeline, the influence value of the change rate of gas impurity content and the influence value of the change rate of gas concentration corresponding to each monitoring point are calculated and recorded as Yi and Xi respectively, so as to obtain the influence value of gas impurity content and gas concentration at each monitoring point through the calculation formula: The dynamic change trend index PDi of the gas pipeline pressure corresponding to each monitoring point within the set time period is obtained, where κ1, κ2, and κ3 respectively represent the weight factor corresponding to the influence value of the set gas impurity content change rate, the weight factor corresponding to the influence value of the gas concentration change rate, and the weight factor of the cross-influence of the gas impurity content change rate and the gas concentration change rate on the dynamic change trend of pressure.

7. A gas transmission pipeline constant pressure control system according to claim 6, characterized in that: The calculation obtains the influence value of the change rate of gas impurity content and the influence value of the change rate of gas concentration corresponding to each monitoring point. The specific calculation process is as follows: By calculation formula: The influence value Yi of the gas impurity content change rate corresponding to each monitoring point is obtained, where Zi is the gas impurity content change rate corresponding to each monitoring point, Zmax is the reference value of the gas impurity content change rate, and ζ is the sensitivity coefficient of the gas impurity content change rate; By calculation formula: The influence value Xi of the gas concentration change rate corresponding to each monitoring point is obtained, where Ni is the gas concentration change rate corresponding to each monitoring point, Nmax is represented as the reference value of the gas concentration change rate, ψ is represented as the sensitivity coefficient of the gas concentration change rate, and N′ is represented as the critical value of the gas concentration change rate.

8. A gas transmission pipeline constant pressure control system according to claim 7, characterized in that: The specific evaluation process of evaluating whether constant pressure control operation is required at each monitoring point corresponding to the gas transmission pipeline is as follows: According to the gas transmission pressure safety risk index corresponding to each monitoring point and the dynamic change trend index of the gas pipeline pressure corresponding to the set time period, the comprehensive control coefficient of the gas pipeline pressure corresponding to each monitoring point is calculated, which is recorded as αi. The result of whether each monitoring point corresponding to the gas transmission pipeline needs to perform constant pressure control operation is recorded as βi. When βi is 0, it indicates that the i-th monitoring point needs to perform constant pressure control operation. When βi is 1, it indicates that the i-th monitoring point does not need to perform constant pressure control operation. Through constant pressure control discriminant: The result βi of whether each monitoring point corresponding to the gas transmission pipeline needs to perform constant pressure control operation is obtained, where T′ represents the standard propagation time range interval corresponding to the set distance segment of the pressure wave, α′ represents the comprehensive control coefficient of the standard gas pipeline pressure, ∧ represents the relationship of and, and ∨ represents the relationship of or.

9. A gas transmission pipeline constant pressure control system according to claim 8, characterized in that: The calculation obtains the comprehensive control coefficient of the gas pipeline pressure at each monitoring point. The specific calculation process is as follows: Substitute the gas transmission pressure safety risk index corresponding to each monitoring point and the dynamic change trend index of the gas pipeline pressure within the set time period into the calculation formula: αi=PSi*λ1+PDi*λ2 to obtain the comprehensive control coefficient αi of the gas pipeline pressure corresponding to each monitoring point, where λ1 and λ2 are the weight factors corresponding to the set gas transmission pressure safety risk index and the dynamic change trend index of the gas pipeline pressure, respectively.

10. A gas transmission pipeline constant pressure control system according to claim 9, characterized in that: The control measures for evaluating constant pressure control are specifically as follows: According to the propagation time of the pressure wave between each monitoring point and the standard propagation time range interval corresponding to the pressure wave set distance segment, when the propagation time of the pressure wave at a certain monitoring point is greater than the upper limit value corresponding to the standard propagation time range interval corresponding to the pressure wave set distance segment, it indicates that the control measure of the constant pressure control is a pressure reduction operation; when the propagation time of the pressure wave at a certain monitoring point is less than the lower limit value corresponding to the standard propagation time range interval corresponding to the pressure wave set distance segment, it indicates that the control measure of the constant pressure control is a pressure increase operation.

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