CN117890034A

CN117890034A - Gas chromatograph leakage monitoring method and response system based on dynamic volume balance

Info

Publication number: CN117890034A
Application number: CN202311698422.6A
Authority: CN
Inventors: 邵开利; 张海东; 李俊珂; 何剑威; 尹红锋
Original assignee: Zhejiang Fuli Analytical Instruments Co ltd
Current assignee: Zhejiang Fuli Analytical Instruments Co ltd
Priority date: 2023-12-12
Filing date: 2023-12-12
Publication date: 2024-04-16

Abstract

The invention discloses a gas chromatograph leakage monitoring method and a response system based on dynamic volume balance, which comprise the following steps: obtaining a flow measurement value of the carrier gas on the secondary gas circuit, a total flow measurement value of the carrier gas at the sample inlet end of the gas chromatograph, a flow measurement value of the carrier gas at the detector end of the gas chromatograph, and a second correction value of the carrier gas in a pipeline between the secondary gas circuit and the gas chromatograph; calculating to obtain a secondary volume unbalance term based on a dynamic volume balance method; acquiring data to be processed with a frame time length of T flow signals, and calculating a second average value based on the data to be processed; and calculating according to the second volume unbalance term and the second average value to obtain a second leakage rate between the second gas circuit and the gas chromatograph, and judging the leakage condition between the second gas circuit and the gas chromatograph based on the second leakage rate. The invention can solve the problem of poor sensitivity and accuracy of monitoring the leakage condition of the gas circuit system.

Description

Gas chromatograph leakage monitoring method and response system based on dynamic volume balance

Technical Field

The invention relates to the technical field of gas chromatographs, in particular to a gas chromatograph leakage monitoring method and a response system based on dynamic volume balance.

Background

At present, carrier gas of a gas chromatograph is provided by gas sources such as a high-pressure steel bottle/a gas generator and the like, and is conveyed to a sample inlet and a detector of the gas chromatograph through a pipeline, a secondary pressure reducing valve in a gas circuit reduces the pressure of the carrier gas to the pressure required by the gas chromatograph, and a gas purifier purifies the carrier gas. The carrier gas of the gas chromatograph is helium, hydrogen, nitrogen, argon. The carrier gas is colorless and odorless, and is often difficult to find after leakage, with significant hysteresis, with serious consequences. For example, expensive helium leaks can cause resource waste and property loss, hydrogen leaks can easily cause accidents such as fire and explosion, and nitrogen leaks can increase the replacement frequency and cost of gas purifiers and detectors.

In the related art, a gas chromatograph is disclosed that uses a flow limiting valve to mechanically limit the flow of carrier gas to a preset flow for an excessive carrier gas flow that is greater than or equal to a fixed flow caused by leakage of carrier gas or the like, but the above-described technical scheme limits the use requirements of the gas chromatograph for a large flow of carrier gas in some cases and cannot sensitively identify the problem of pipe leakage.

Disclosure of Invention

The invention aims to overcome the technical defects, and provides a gas chromatograph leakage monitoring method and a response system based on dynamic volume balance, which solve the technical problems of poor sensitivity and accuracy of leakage condition monitoring of a gas circuit system in the prior art.

In order to achieve the above technical object, in a first aspect, the present invention provides a gas chromatograph leakage monitoring method based on dynamic volume balance, comprising the following steps:

obtaining a flow measurement value of the carrier gas on the secondary gas circuit, a total flow measurement value of the carrier gas at the sample inlet end of the gas chromatograph, a flow measurement value of the carrier gas at the detector end of the gas chromatograph, and a second correction value of the carrier gas in a pipeline between the secondary gas circuit and the gas chromatograph;

calculating a secondary volume unbalance item according to the flow measurement value of the carrier gas on the secondary gas circuit, the total flow measurement value of the carrier gas at the sample inlet end, the flow measurement value of the carrier gas at the detector end and the second correction value based on a dynamic volume balance method;

acquiring data to be processed with a frame time length of T flow signals, and calculating a second average value based on the data to be processed;

and calculating a second leakage rate between the second gas circuit and the gas chromatograph according to the second volume unbalance item and the second average value, and judging the leakage condition between the second gas circuit and the gas chromatograph based on the second leakage rate.

Compared with the prior art, the gas chromatograph leakage monitoring method based on dynamic volume balance has the beneficial effects that:

According to the gas chromatograph leakage monitoring method based on dynamic volume balance, firstly, a flow measurement value of carrier gas on a secondary gas circuit, a total flow measurement value of carrier gas at a sample inlet end of the gas chromatograph, a flow measurement value of carrier gas at a detector end of the gas chromatograph and a second correction value of carrier gas in a pipeline between the secondary gas circuit and the gas chromatograph are obtained; calculating to obtain a secondary volume unbalance item based on a dynamic volume balance method; then obtaining data to be processed with a frame time length of T flow signals, and calculating a second average value based on the data to be processed; and calculating a second leakage rate between the second gas circuit and the gas chromatograph according to the second volume unbalance item and the second average value, and judging the leakage condition between the second gas circuit and the gas chromatograph based on the second leakage rate.

According to the invention, under the condition that the use of the carrier gas with the excessively high or excessively low flow is not limited, the gas flow monitoring device arranged at the upstream and downstream positions of the gas path can monitor and display the flow characteristics of the carrier gas at different pipeline positions on line in real time, the leakage condition between the secondary gas path and the gas chromatograph is monitored by utilizing a dynamic volume balance principle, and the high-precision rapid detection gas flow monitoring device is matched with a comprehensive analysis method and a statistical decision method to reduce the adverse effects of the monitoring delay and the monitoring error on the leakage judgment result and the possible consequences thereof, thereby improving the sensitivity and accuracy of the leakage monitoring of the gas path system.

The pipeline from the air source to the secondary pressure reducing valve is defined as a primary air pipeline, the primary air pipeline is divided into a plurality of secondary air pipelines through the secondary pressure reducing valve, and the secondary air pipeline is from the secondary pressure reducing valve to the gas chromatograph (Gas Chromatography, GC).

According to some embodiments of the invention, determining a leak condition between a secondary gas circuit and the gas chromatograph based on the second leak rate comprises the steps of:

if the second leakage rate is larger than a preset leakage threshold value, acquiring a first abnormal signal duration time;

if the duration of the first abnormal signal is larger than a preset time threshold, judging that carrier gas transportation abnormality exists between the second-stage gas circuit and the gas chromatograph.

According to some embodiments of the invention, after determining that there is a carrier gas delivery abnormality between the secondary gas circuit and the gas chromatograph, the method comprises the steps of:

judging whether the pressure of the gas flow monitoring device on the secondary gas circuit shows a descending trend or not, and judging whether the volume consumption of the carrier gas shows an ascending trend or not;

when the pressure of the gas flow monitoring device on the secondary gas circuit shows a descending trend and the volume consumption of the carrier gas shows an ascending trend, acquiring a second abnormal signal duration;

if the duration of the second abnormal signal is larger than a preset time threshold, judging that leakage exists between the second-stage gas circuit and the gas chromatograph.

According to some embodiments of the present invention, obtaining a second correction value for a carrier gas in a conduit between a secondary gas circuit and a gas chromatograph includes the steps of:

acquiring pressure P of starting point of secondary gas circuit pipeline ₁ And pressure at the end point P ₂ The inner diameter D of the pipeline, the hydraulic friction coefficient tau and the relative density of carrier gasρ, carrier gas compression factor Z, gas temperature T and pipeline length L, and calculating to obtain a correction value v of the carrier gas volume per second in the standard-state secondary gas circuit pipeline _{2 Standard} ：

Calculating according to the correction value of the carrier gas volume per second in the standard-state secondary gas circuit pipeline to obtain the correction value v of the carrier gas volume per second in the secondary gas circuit pipeline in the actual state _{2 actual} ：

According to v _{2 actual} And calculating to obtain a second correction value of the carrier gas in the pipeline between the secondary gas circuit and the gas chromatograph in a preset time period.

compared with historical data, whether the carrier gas volume consumption of the secondary gas circuit shows an ascending trend or not and whether the pressure shows a descending trend or not are compared, wherein the judging method of the change trend of the carrier gas volume consumption is as follows:

extraction of V _Second-level V of the data of (2) _Second-level For the volume consumption of carrier gas on the current secondary gas circuit, and calculating V _Second-level A first curve over time;

extracting the method parameters of the GC on the current secondary gas path, inquiring all data consistent with the method parameters of the GC on the current secondary gas path in the current day in a historical database, and extracting V with the same time length as that in the first curve _{Second order f} And calculate V _{Second order f} And judging whether leakage exists between the second-stage gas circuit and the gas chromatograph by judging the difference between the first curve and the second curve along with the time change of the second curve.

According to some embodiments of the present invention, after calculating a secondary volume imbalance term for a secondary gas path carrier gas based on a dynamic volume balancing method, the method comprises the steps of:

under the normal condition of the gas circuit, determining a secondary volume unbalance item V of a secondary gas circuit carrier gas _B Mean value (θ) ₀ ) And mean square error (sigma) ₀ )；

Determining an alternative hypothesis θ based on data in the event of gas path leakage _x ：

Wherein V is _Second-level A is the volume consumption of carrier gas on the current secondary gas path _x Is theta and theta _x Corresponding coefficients are calculated according to a priori distribution function of carrier gas leakage;

collecting data for judgment and inspection, and assuming that the y sample backup alternative is theta _x The decision function of (2) is:

wherein n is the single maximum value of the sample, the single maximum value is corrected by adopting a function compensation method, and the corrected decision function is R _x ^* (y) if R _x (y) is greater than or equal to 0, R _x ^* (y)＝R _x (y) if R _x (y)＜0，R _x ^* (y)＝0；

Judging leakage; alpha is the false alarm rate of the leakage monitoring system, beta is the leakage alarm rate of the leakage monitoring system, alpha and beta are 0.5%, and the threshold value of the decision function is {0, ln [ (1-beta)/alpha ]]-a }; when R is _x ^* (y)≥ln[(1-β)/α]And when the gas chromatograph is in operation, leakage occurs between the secondary gas circuit and the gas chromatograph.

In a second aspect, the present invention provides a gas chromatograph leakage monitoring method based on dynamic volume balance, including the following steps:

obtaining a flow measurement value of the carrier gas on the primary gas path, a flow measurement value of the carrier gas on the secondary gas path and a first correction value in a pipeline between the primary gas path and the secondary gas path;

calculating to obtain a primary volume unbalance item according to a flow measurement value of the carrier gas on the primary gas path, a flow measurement value of the carrier gas on the secondary gas path and a first correction value in a pipeline between the primary gas path and the secondary gas path based on a dynamic volume balance method;

acquiring data to be processed with a frame time length of T flow signals, and calculating a first average value based on the data to be processed;

and calculating according to the primary volume unbalance item and the first average value to obtain a first leakage rate between the primary air channel and the secondary air channel, and judging the leakage condition between the primary air channel and the secondary air channel based on the first leakage rate.

According to some embodiments of the present invention, determining a leakage condition between a primary gas path and a secondary gas path based on the first leakage rate includes the steps of:

if the first leakage rate is larger than a preset leakage threshold value, acquiring a third abnormal signal duration time;

if the duration of the third abnormal signal is larger than the preset time threshold, judging that carrier gas conveying abnormality exists between the first-stage gas circuit and the second-stage gas circuit.

In a third aspect, the present invention provides a gas chromatograph leak monitoring response system based on dynamic volume balance, including:

the gas flow monitoring device is used for acquiring a flow measurement value of the carrier gas on the secondary gas circuit, a total flow measurement value of the carrier gas at the sample inlet end of the gas chromatograph, a flow measurement value of the carrier gas at the detector end of the gas chromatograph and a second correction value of the carrier gas in a pipeline between the secondary gas circuit and the gas chromatograph;

the volume unbalance item calculation module is in communication connection with the gas flow monitoring device, and calculates to obtain a secondary volume unbalance item according to a flow measurement value of the carrier gas on the secondary gas path, a total flow measurement value of the carrier gas at the sample inlet end, a flow measurement value of the carrier gas at the detector end and the second correction value based on a dynamic volume balance method;

The average value calculation module is used for obtaining to-be-processed data with a frame time length of T flow signals and calculating a second average value based on the to-be-processed data;

the leakage judging module is in communication connection with the volume unbalance item calculating module and the average value calculating module, and is used for calculating a second leakage rate between the second gas circuit and the gas chromatograph according to the second volume unbalance item and the second average value, and judging the leakage condition between the second gas circuit and the gas chromatograph based on the second leakage rate.

According to some embodiments of the invention, the dynamic volume balance based gas chromatograph leak monitoring response system further comprises: and the response module is in communication connection with the leakage judging module and is used for generating a corresponding control instruction according to the type of the leaked gas and the leakage condition.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the present invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings, in which the summary drawings are to be fully consistent with one of the drawings of the specification:

FIG. 1 is a flow chart of a dynamic volume balance based gas chromatograph leak monitoring method according to one embodiment of the present invention;

FIG. 2 is a flow chart of a dynamic volume balance based gas chromatograph leak monitoring method according to one embodiment of the present invention;

FIG. 3 is a flow chart of a dynamic volume balance based gas chromatograph leak monitoring method according to an embodiment of the present invention;

FIG. 4 is a flow chart of a dynamic volume balance based gas chromatograph leak monitoring method according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a dynamic volume balance based gas chromatograph leak monitoring response system according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

It should be noted that although functional block diagrams are depicted as block diagrams, and logical sequences are shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the block diagrams in the system. The terms first, second and the like in the description and in the claims and in the above-described figures, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.

The carrier gas of the gas chromatograph is provided by gas sources such as a high-pressure steel bottle/a gas generator and the like, and is conveyed to a sample inlet and a detector of the gas chromatograph through a pipeline, the pressure of the carrier gas is reduced to the pressure required by the gas chromatograph by a secondary pressure reducing valve in a gas circuit, and the carrier gas is purified by a gas purifier and is helium, hydrogen, nitrogen and argon. The carrier gas is colorless and odorless, and is often difficult to find after leakage, with significant hysteresis, with serious consequences. For example, expensive helium leaks can cause resource waste and property loss, hydrogen leaks can easily cause accidents such as fire and explosion, and nitrogen leaks can increase the replacement frequency and cost of gas purifiers and detectors. Internal leaks in gas chromatographs, such as loosening of column joints, breaking of columns, etc., often manifest abnormal sample inlet flow or pressure and give alarm cues. But the external leak of the gas chromatograph has no corresponding monitoring and response mechanism.

Embodiments of the present invention will be further described below with reference to the accompanying drawings.

Referring to fig. 1, fig. 1 is a flowchart of a dynamic volume balance-based gas chromatograph leak monitoring method according to an embodiment of the present invention; the dynamic volume balance based gas chromatograph leak monitoring method includes, but is not limited to, steps S110 to S140.

Step S110, obtaining a flow measurement value of carrier gas on a secondary gas circuit, a total flow measurement value of carrier gas at a sample inlet end of a gas chromatograph, a flow measurement value of carrier gas at a detector end of the gas chromatograph, and a second correction value of carrier gas in a pipeline between the secondary gas circuit and the gas chromatograph;

step S120, calculating to obtain a secondary volume unbalance item according to a flow measurement value of the carrier gas on the secondary gas path, a total flow measurement value of the carrier gas at the sample inlet end, a flow measurement value of the carrier gas at the detector end and a second correction value based on a dynamic volume balance method;

step S130, obtaining data to be processed of which the frame time length is T flow signals, and calculating a second average value based on the data to be processed;

and step S140, calculating a second leakage rate between the second gas circuit and the gas chromatograph according to the second volume unbalance item and the second average value, and judging the leakage condition between the second gas circuit and the gas chromatograph based on the second leakage rate.

In one embodiment, a dynamic volume balance based gas chromatograph leak monitoring method includes the steps of: obtaining a flow measurement value of the carrier gas on the secondary gas circuit, a total flow measurement value of the carrier gas at the sample inlet end of the gas chromatograph, a flow measurement value of the carrier gas at the detector end of the gas chromatograph, and a second correction value of the carrier gas in a pipeline between the secondary gas circuit and the gas chromatograph; calculating a secondary volume unbalance item according to the flow measurement value of the carrier gas on the secondary gas circuit, the total flow measurement value of the carrier gas at the sample inlet end, the flow measurement value of the carrier gas at the detector end and the second correction value based on a dynamic volume balance method; acquiring data to be processed with a frame time length of T flow signals, and calculating a second average value based on the data to be processed; and calculating according to the second volume unbalance term and the second average value to obtain a second leakage rate between the second gas circuit and the gas chromatograph, and judging the leakage condition between the second gas circuit and the gas chromatograph based on the second leakage rate.

The gas flow monitoring device configured at the upstream and downstream positions of the gas path can monitor and display the flow characteristics of the carrier gas at different pipeline positions on line in real time under the condition of not limiting the carrier gas with excessively high or excessively low flow, the leakage condition of the primary gas path and the secondary gas path is monitored by utilizing a dynamic volume balance principle, and the gas flow monitoring device for high-precision rapid detection is matched with a comprehensive analysis method and a statistical decision method to reduce the adverse effects of the monitoring delay and the monitoring error on the leakage judgment result and the possible consequences thereof, thereby improving the sensitivity and the accuracy of the leakage monitoring of the gas path system.

The gas flow monitoring device can be provided with a response module, can automatically perform corresponding treatment according to a leakage judging result, and particularly, does not need a technician to manually close a gas source on site and can automatically and timely stop the supply of hydrogen on a primary gas path or a secondary gas path under the condition of dangerous gas hydrogen leakage, so that the gas chromatograph and the technician using the gas chromatograph are prevented from being in dangerous environments, and the technician is also allowed to remotely operate and control, so that the technician can work safely, efficiently and conveniently.

The control software of the gas chromatograph can perform proper treatment according to the gas type, the leakage position and the leakage level, when the gas chromatograph control software is used for dealing with the leakage of the carrier gas, flammable and explosive hydrogen or expensive helium possibly has serious leakage, the gas flow monitoring device of the primary gas path or the secondary gas path can be controlled to stop the supply of the hydrogen or the helium to the gas chromatograph, so that the resource waste and the economic loss caused by the leakage of the helium can be effectively prevented, accidents such as fire explosion caused by the leakage of the hydrogen are prevented, the safe and low-cost guarantee service is provided for technicians using the gas chromatograph, the technicians can be more relieved, the gas chromatograph can be controlled to stop analyzing preferentially when the nitrogen or the argon with low risk coefficient possibly has leakage, and the gas chromatograph is shut down according to the normal operation sequence, and the damage to the chromatographic column in the high-temperature state caused by the abrupt stop of the carrier gas can be avoided.

In addition, according to the invention, the gas flow monitoring device has the function of accumulating the flow of the carrier gas, the gas flow monitoring device arranged on the primary gas path can calculate the difference value between the total amount of the carrier gas flowing out and the preset total amount of the gas source and compare the difference value with the preset threshold value, the obtained result is used for reminding a technician using the gas chromatograph to replace a new gas source in time in advance, and the gas flow monitoring device arranged on the secondary gas path can accumulate the total amount of the carrier gas flowing through the gas purifier and is used for guiding the technician to replace the new gas purifier, so that the influence of unclean gas on the performances of chromatographic column, detector and the like of the gas chromatograph and the sensitivity and the like is avoided.

The flow and pressure monitored by the gas flow monitoring device positioned on the secondary gas circuit can provide reference basis for technicians to identify the problems of the flow and the pressure of the sample inlet of the gas chromatograph, for example, when the gas chromatograph has the problems of insufficient flow and under-pressure of the sample inlet, whether the gas supply of the secondary gas circuit is sufficient can be determined by checking the flow and the pressure data monitored by the gas flow monitoring device positioned on the secondary gas circuit.

The comprehensive analysis leakage judgment method based on dynamic volume balance between the secondary gas circuit and the gas chromatograph comprises the following steps:

calculating carrier gas leakage rate based on a dynamic volume balance formula, and acquiring a first abnormal signal duration time if the carrier gas leakage rate is greater than a preset leakage threshold value; if the duration of the first abnormal signal is larger than a preset time threshold, judging that the carrier gas transportation abnormality of the secondary gas circuit possibly exists. Judging whether the pressure of the secondary gas circuit is reduced or not and whether the volume consumption is increased or not; or compared with historical data, whether the carrier gas volume consumption of the secondary gas circuit shows an ascending trend, whether the pressure shows a descending trend, and the calculation formula of the secondary volume imbalance term:

V _B (t)＝∫Q _second-level dt-(∫Q _{GC sample inlet} dt+∫Q _{GC detector} dt)-Δv ₂

Q _{GC sample inlet} ＝Q _{Column flow rate} +Q _{Split flow rate} +Q _{Spacer purge} The total flow measurement value of the carrier gas at the sample inlet end of the gas chromatograph is the sum of column flow, split flow and spacer purge flow.

Wherein V is _B (t) is the volume imbalance term of the carrier gas during time t, Q _Second-level Carrier gas on the corresponding secondary gas path of each gas chromatographInstantaneous flow measurement, Q _{GC sample inlet} Is the total flow measurement value Q of carrier gas at the sample inlet end of the gas chromatograph _{GC detector} For gas chromatograph detector end carrier gas flow measurement values, deltav, depending on carrier gas and detector type ₂ Is the second correction value of the carrier gas in the pipeline between the secondary gas circuit and the gas chromatograph.

Q _{GC detector} Regarding the carrier gas type and the detector type, when the carrier gas is helium and the detector is a Flame Ionization Detector (FID):

Q _{GC detector} ＝Q _{Detector tail blow}

When the carrier gas is hydrogen and the detector is a Thermal Conductivity Detector (TCD):

Q _{GC detector} ＝Q _{Detector tail blow} +Q _{Detector reference gas}

When the carrier gas is nitrogen and the detector is an Electron Capture Detector (ECD);

Q _{GC detector} ＝Q _{Detector tail blow} +Q _{Detector cationic purge} 。

In one embodiment, the collection frequency of the signals in the gas flow monitoring device is 100Hz, the extraction frequency of the signals is 50Hz, 25Hz, 10Hz, 1Hz and the like for technicians to select, the data is transmitted to the control software of the gas chromatograph, the control software takes the signals in a set time period T (such as 5min, 8min, 10min and the like) as one frame of data to be processed, and the Q is extracted _Second-level 、Q _{GC sample inlet} 、Q _{GC detector} Each frame of data to be processed having a time length T is divided into sections of equal time length j (e.g., 1s, 5s, 10 s), and thus, one frame of signal is divided into m (=t/j) sections in total, the Start times of the different sections are stored in the Start array, and the End time positions are stored in the End array.

For example, in the kth (1. Ltoreq.k.ltoreq.m) section, the start point of the section is the time i (in s), the end time is the time i+j (in s), and the start position of the kth+1th section is i+j+1, and the cycle is repeated.

The specific judging process is as follows:

judgment condition 1Calculating carrier gas leakage rate in intervalAnd is associated with a predetermined carrier gas leakage rate->Comparing, ifIs greater than->And the abnormal signal duration time T (1) is larger than the set signal minimum duration time T(s), the condition that the abnormality of the carrier gas transportation of the secondary gas path exists from the Start time Start (k) corresponding to the kth interval is considered.

(a) Calculating the secondary volume unbalance term V of the carrier gas in each interval according to the following formula _B (i,i+j)

Wherein Q is _Second-level Measuring the instantaneous flow of the carrier gas on the secondary gas circuit corresponding to each gas chromatograph, Q _{GC sample inlet} Is the total flow measurement value Q of carrier gas at the sample inlet end of the gas chromatograph _{GC detector} For gas chromatograph detector end carrier gas flow measurement values, deltav, depending on carrier gas and detector type ₂ Is the correction value of the carrier gas in the pipeline between the secondary gas circuit and the gas chromatograph. Deltav ₂ A second correction value v comprising the volume of carrier gas per second in the secondary gas path pipeline _{2 actual} And measurement error v of gas flow rate monitoring device _{2 measurement error} Considering that the actual pipeline condition is complex, the correction is carried out after the experiment on the basis of the calculated value:

v _{2 Standard} Is the correction value of the carrier gas volume per second in the secondary gas path pipeline, P ₁ 、P ₂ The pressure (MPa) of the starting point and the ending point of the two-stage gas circuit pipeline is D is the inner diameter (cm) of the pipeline, tau is the hydraulic friction coefficient, rho is the relative density of carrier gas, Z is the carrier gas compression factor, T is the gas temperature (K), and L is the length (m) of the pipeline.

v _{2 actual} Is the correction value of the carrier gas volume per second in the secondary gas path pipeline in the actual state, P ₀ 、T ₀ Atmospheric pressure (101.3 kPa) and temperature (293K) in a standard state, and P, T atmospheric pressure (MPa) and temperature (K) in an actual state;

(b) Calculating the mean value V of the carrier gas volume in a frame of signal _{B means}

(c) Calculating carrier gas leakage rates in different areasSum signal duration T (1)

And judging the second condition, and judging whether the change trend of the pressure and the volume consumption of the second-stage gas circuit meets the requirement. Specifically, starting from a k-e (0 < e < k) interval identified as abnormal carrier gas transportation of the secondary gas path, judging whether the pressure of the gas flow monitoring device on the secondary gas path shows a descending trend or not, and judging whether the volume consumption of the carrier gas shows an ascending trend or not:

(a) Starting from the Start time Start (k-e) corresponding to the k-e interval, using the formula ΔP _Second-level (i)＝P _Second-level (i+1)－P _Second-level (i) Calculating the pressure difference delta P at adjacent moments _Second-level (i)<0, and a duration T (2) when the above formula is established;

(b) Calculating from the k-e interval using the formula DeltaV _Second-level (k)＝V _Second-level (k+1)－V _Second-level (k) Calculating the difference DeltaV of the volume consumption of adjacent sections _Second-level (k)>0, and a duration T (3) when the above formula is established;

if the pressure difference delta P is at adjacent time _Second-level <Duration T (2) of 0 and difference DeltaV between adjacent interval volume consumption _Second-level >And if the duration time T (3) of 0 is larger than the set signal minimum duration time T(s), the pressure on the secondary gas circuit is considered to be reduced, and the volume consumption is considered to be increased.

In summary, only when the above 2 judging conditions are satisfied at the same time, it can be judged that leakage occurs between the secondary gas circuit and the gas chromatograph, otherwise, it can be judged as suspected leakage.

In addition, if the method parameters such as the sample inlet (column flow, split ratio), the chromatographic column, the detector parameters, etc. remain constant for a long time during the use of GC (gas chromatograph), the trend of the volume consumption in the above-mentioned judgment condition II is obtained by comparing with the data of different sections in the same frame signal,

The second judgment condition can also be modified as follows: compared with historical data, whether the carrier gas volume consumption of the secondary gas circuit shows an ascending trend or not and whether the pressure shows a descending trend or not are compared, wherein the judging method of the change trend of the carrier gas volume consumption is as follows:

(a) Extracting V from the start time of the kth interval identified as abnormal carrier gas delivery to the end time of the frame data _Second-level And calculate V _Second-level Over timeIs a graph of the curve of (2),

(b) Extracting GC method parameters from the starting moment of the k-th interval identified as abnormal carrier gas transportation, wherein the GC method parameters comprise parameters of a GC sample inlet (such as total flow, column flow, split ratio and the like), chromatographic column parameters and detector parameters (such as tail blowing flow and the like);

(c) Querying all data consistent with the method parameters of GC in (b) in the current day in a historical database, and extracting V with the same time length as that in (a') _Second-level (f) Data, draw V _Second-level (f) A time-dependent curve;

(d) Judging V _Second-level (f) Time variation and V _Second-level Whether the change over time exhibits a significant difference.

Referring to fig. 2, fig. 2 is a flow chart of a dynamic volume balance based gas chromatograph leak monitoring method according to an embodiment of the present invention; the dynamic volume balance based gas chromatograph leak monitoring method includes, but is not limited to, steps S210 to S220.

Step S210, if the second leakage rate is greater than the preset leakage threshold value, acquiring the duration of the first abnormal signal;

step S220, if the duration of the first abnormal signal is greater than the preset time threshold, judging that the carrier gas transportation abnormality exists between the secondary gas circuit and the gas chromatograph.

Judging the leakage condition between the secondary gas circuit and the gas chromatograph based on the second leakage rate, comprising the following steps: if the second leakage rate is greater than a preset leakage threshold value, acquiring the duration time of the first abnormal signal; if the duration of the first abnormal signal is larger than a preset time threshold, judging that carrier gas transportation abnormality exists between the second-stage gas circuit and the gas chromatograph.

Referring to fig. 3, fig. 3 is a flowchart of a dynamic volume balance-based gas chromatograph leak monitoring method according to an embodiment of the present invention; the dynamic volume balance based gas chromatograph leak monitoring method includes, but is not limited to, steps S310 to S330.

Step S310, judging whether the pressure of the gas flow monitoring device on the secondary gas circuit shows a descending trend or not, and judging whether the volume consumption of the carrier gas shows an ascending trend or not;

step S320, when the pressure of the gas flow monitoring device on the secondary gas circuit shows a descending trend and the volume consumption of the carrier gas shows an ascending trend, obtaining a second abnormal signal duration;

in step S330, if the duration of the second abnormal signal is greater than the preset time threshold, it is determined that there is leakage between the second gas circuit and the gas chromatograph.

After judging that the carrier gas transportation abnormality exists between the secondary gas circuit and the gas chromatograph, the method comprises the following steps: judging whether the pressure of the gas flow monitoring device on the secondary gas circuit shows a descending trend or not, and judging whether the volume consumption of the carrier gas shows an ascending trend or not; when the pressure of the gas flow monitoring device on the secondary gas circuit shows a descending trend and the volume consumption of the carrier gas shows an ascending trend, acquiring a second abnormal signal duration; if the duration of the second abnormal signal is larger than the preset time threshold, judging that leakage exists between the second gas circuit and the gas chromatograph.

And judging whether the change trend of the pressure and the volume consumption of the secondary gas circuit meets the requirements. Specifically, from the kth interval identified as abnormal carrier gas transportation of the secondary gas path, whether the pressure of the gas flow monitoring device on the secondary gas path shows a descending trend or not is judged, and whether the volume consumption of the carrier gas shows an ascending trend or not is judged. When the pressure of the gas flow monitoring device on the secondary gas circuit shows a descending trend, the volume consumption of the carrier gas shows an ascending trend, the duration of the second abnormal signal is longer than a preset time threshold, and the leakage between the secondary gas circuit and the gas chromatograph is judged.

After judging that the carrier gas transportation abnormality exists between the secondary gas circuit and the gas chromatograph, the method comprises the following steps: compared with historical data, whether the carrier gas volume consumption of the secondary gas circuit shows an ascending trend or not and whether the pressure shows a descending trend or not are compared, wherein the judging method of the change trend of the carrier gas volume consumption is as follows: extraction of V _Second-level V of the data of (2) _Second-level For the volume consumption of carrier gas on the current secondary gas circuit, and calculating V _Second-level A first curve over time; extracting the method parameters of the GC on the current secondary gas path, inquiring all data consistent with the method parameters of the GC on the current secondary gas path in the current day in a historical database, and extracting V with the same time length as that in the first curve _{Second order f} And calculate V _{Second order f} And judging whether leakage exists between the secondary gas circuit and the gas chromatograph by judging the difference between the first curve and the second curve along with the time change of the second curve.

In one embodiment, a dynamic volume balance based gas chromatograph leak monitoring method includes the steps of: obtaining a flow measurement value of the carrier gas on the secondary gas circuit, a total flow measurement value of the carrier gas at the sample inlet end of the gas chromatograph, a flow measurement value of the carrier gas at the detector end of the gas chromatograph, and a second correction value of the carrier gas in a pipeline between the secondary gas circuit and the gas chromatograph; and calculating based on a dynamic volume balance method according to the flow measurement value of the carrier gas on the secondary gas path, the total flow measurement value of the carrier gas at the sample inlet end, the flow measurement value of the carrier gas at the detector end and the second correction value to obtain a secondary volume imbalance term.

Judging leakage; alpha is the false alarm rate of the leakage monitoring system, beta is the leakage alarm rate of the leakage monitoring system, alpha and beta are 0.5%, and the threshold value of the decision function is {0, ln [ (1-beta)/alpha ]]-a }; when R is _x ^* (y)≥ln[(1-β)/α]And when the gas is leaked between the secondary gas circuit and the gas chromatograph.

The statistical decision leakage judging method based on dynamic volume balance comprises the following steps: the sealing gasket at the gas path joint between the secondary gas path and the gas chromatograph causes small leakage due to aging and irregular installation after long-time use. For the small leakage, the small leakage can be identified by a statistical decision method-a multi-sequential probability ratio test method, and a sufficiently small false alarm rate can be ensured. However, when the method is first established or used, sufficient data may be used to determine some parameters after statistical analysis, or some empirical values provided may be used, as follows:

1. Under the normal condition of a gas circuit, determining a volume unbalance term V of carrier gas _B Mean value (θ) ₀ ) And mean square error (sigma) ₀ )；

(a) Under the normal condition of the gas path, different GC methods, secondary pressure reducing valve pressures and the like are set to collect sufficient data, wherein the GC methods mainly set parameters such as a carrier gas control mode, a split mode (split/non-split), carrier gas saving setting, chromatographic column types, detector flow and the like, and the secondary pressure reducing valve pressures mainly set between 0.3 and 0.5 MPa. Because the parameters such as the length and the inner diameter of the pipeline adopted between different secondary gas circuits have smaller difference, the influence of the pipeline parameters is negligible.

(b) Selecting proper time length j, and calculating the two-stage gas paths in different areas according to the acquired data

Volume imbalance term of internal carrier gas V _B (t), wherein i starts from 0:

(c) Reference to GB/T4882-2001 to V _B (T) carrying out a normalization test according to GB/T4883-2008

And stability test processing is performed by Q _{GC sample inlet} Abnormal data and non-stationary signal caused by abnormal fluctuation, and V after filtering _B (t) compliance with (θ) ₀ ,σ ₀ ² ) And (3) generating new data Z obeying the normal distribution (0, 1) through normalization processing. If the gas path is air leakage, the normalized Z is subjected to the distribution of (theta, 1), and theta is a non-0 parameter value. Whether the secondary air path is normal or not determines that theta is 0 or a non-0 value.

2. Determining an alternative hypothesis θ based on data in the event of gas path leakage _x

Opposite passing markV after normalization _B (t) distribution gives 2 hypotheses, original hypothesis H ₀ : θ=0, the second-stage gas path is normal, other alternatives assume H _x ：θ＝θ _x Leakage of different degrees, theta, occurs in the secondary gas circuit _x A parameter value other than 0, x is the number of alternative hypotheses. Determining θ from a priori distribution of leakage of varying degrees and the average time required to verify various leaks _x Is a value of (a). θ _x The calculation formula of (2) is simplified as follows:

wherein V is _Second-level For this purpose, the volume consumption of the carrier gas, a _x Is theta and theta _x The corresponding coefficients are calculated according to a priori distribution function of the carrier gas leakage.

But also taking into account the minimum volume of carrier gas (V _min )

In the formula dv _{2 actual} The estimation error of the carrier gas volume in the secondary gas path pipeline in the actual state; dv _{2 measurement error} Is the integrated error of the measurement result; j is a time interval;

in order to increase the detection speed, 2-3 alternative hypotheses may be set for simultaneous detection for each degree of leakage.

3. And (3) judging and checking:

(a) Determining good parameter theta ₀ 、σ ₀ 、θ _x And then, data can be collected for judgment and inspection. Each alternative hypothesis corresponds to a decision function, and the y sample back alternative hypothesis is theta _x The decision function of (2) is:

(b) To eliminate theExcept for detection delay caused by negative values accumulated by the decision function in a normal state, correcting by adopting a function compensation method, wherein the corrected decision function is R _x ^* (y) if R _x (y) is greater than or equal to 0, R _x ^* (y)＝R _x (y) if R _x (y)＜0，R _x ^* (y)＝0。

(c) Judging leakage, wherein alpha is the false alarm rate of the leakage monitoring system, beta is the leakage alarm rate of the leakage monitoring system, alpha and beta are usually 0.5%, and the threshold value of the judgment function is {0, ln [ (1-beta)/alpha]}. When R is _x ^* (y)≥ln[(1-β)/α]And if not, continuing sampling judgment.

Referring to fig. 4, fig. 4 is a flowchart of a dynamic volume balance-based gas chromatograph leak monitoring method according to an embodiment of the present invention; the dynamic volume balance based gas chromatograph leak monitoring method includes, but is not limited to, steps S410 to S440.

Step S410, obtaining a flow measurement value of the carrier gas on the primary gas path, a flow measurement value of the carrier gas on the secondary gas path and a first correction value in a pipeline between the primary gas path and the secondary gas path;

step S420, calculating to obtain a primary volume imbalance term based on a dynamic volume balance method according to a flow measurement value of carrier gas on a primary gas path, a flow measurement value of carrier gas on a secondary gas path and a first correction value in a pipeline between the primary gas path and the secondary gas path;

Step S430, obtaining data to be processed of which the frame time length is T flow signals, and calculating a first average value based on the data to be processed;

step S440, a first leakage rate between the first-stage gas circuit and the second-stage gas circuit is obtained through calculation according to the first-stage volume unbalance item and the first average value, and the leakage condition between the first-stage gas circuit and the second-stage gas circuit is judged based on the first leakage rate.

In one embodiment, a dynamic volume balance based gas chromatograph leak monitoring method includes the steps of: obtaining a flow measurement value of the carrier gas on the primary gas path, a flow measurement value of the carrier gas on the secondary gas path and a first correction value in a pipeline between the primary gas path and the secondary gas path; calculating to obtain a primary volume unbalance item according to a flow measurement value of the carrier gas on the primary gas path, a flow measurement value of the carrier gas on the secondary gas path and a first correction value in a pipeline between the primary gas path and the secondary gas path based on a dynamic volume balance method; acquiring data to be processed with a frame time length of T flow signals, and calculating a first average value based on the data to be processed; and calculating according to the primary volume unbalance item and the first average value to obtain a first leakage rate between the primary air channel and the secondary air channel, and judging the leakage condition between the primary air channel and the secondary air channel based on the first leakage rate.

The comprehensive analysis leakage judging method based on dynamic volume balance comprises the following steps:

the calculation formula of the dynamic volume balance method between the first-stage gas circuit and the second-stage gas circuit is as follows:

v in _A (t) is the volume imbalance term of the carrier gas during time t, Q _{First level} For measuring instantaneous flow of carrier gas on primary gas circuit, Q _Second-level For the instantaneous flow measurement of the carrier gas on the secondary gas paths, N secondary gas paths, deltav, are assumed ₁ Is the first correction value of the carrier gas in the pipeline between the first-stage gas circuit and the second-stage gas circuit.

The comprehensive analysis leakage judgment method based on dynamic volume balance between the first-stage gas circuit and the second-stage gas circuit comprises the following steps:

the acquisition frequency of signals in the gas flow monitoring device is 100Hz, the extraction frequency of the signals is 50Hz, 25Hz, 10Hz, 1Hz and the like for technicians to select, the data is transmitted to control software of the gas chromatograph, the control software takes the signals in a set time length T (such as 5min, 8min, 10min and the like) as a frame of data to be processed, and the Q in the data is extracted _{First level} And Q _Second-level Each frame timeSince data of length T is divided into sections of equal time length j (for example, 1s, 5s, and 10 s), one frame of signal is divided into m (=t/j) sections in total, the Start time of each section is stored in the Start array, and the End time position is stored in the End array. For example, in the kth (1. Ltoreq.k.ltoreq.m) section, the start point of the section is the time i (in s), the end time is the time i+j (in s), and the start position of the kth+1th section is i+j+1, and the cycle is repeated.

The specific judging process is as follows:

1. calculating a primary volume unbalance term V of carrier gas in each interval according to the following formula _A (i,i+j)

Wherein Q is _{First level} For measuring instantaneous flow of carrier gas on primary gas circuit, Q _Second-level Is the instantaneous flow measurement value of carrier gas on the secondary gas circuit, wherein N is the number of the secondary gas circuits in actual use (N is more than or equal to 1 and less than or equal to 8), and Deltav ₁ Comprises a correction value v of the carrier gas volume per second in a first-stage gas path pipeline _{1 actual} And measurement error v of gas flow rate monitoring device _{1 measurement error} Considering that the actual pipeline condition is complex, the correction is required to be carried out after the experiment on the basis of the calculated value:

v _{1 actual} Is the correction value of the carrier gas volume per second in the primary gas path pipeline in the actual state, P ₀ 、T ₀ Atmospheric pressure (101.3 kPa) and temperature (293K) in a standard state, and P, T atmospheric pressure (MPa) and temperature (K) in an actual state;

v _{1 Standard} Is per second in the primary gas path pipeline under standard stateCorrection value of carrier gas volume, P ₁ 、P ₂ Is the pressure (MPa) of the starting point and the ending point of the first-stage gas circuit pipeline, D is the pipeline inner diameter (cm), tau is the hydraulic friction coefficient, rho is the relative density of carrier gas, Z is the carrier gas compression factor, T is the gas temperature (K), and L is the pipeline length (m).

Calculating the mean value of the carrier gas volume in a frame signal to obtain a first mean value V of the carrier gas volume in the frame signal _{A means} ：

2. Calculating first leakage rate of different intervalsSum signal duration T (4)

Judging condition one: if the calculated interval first leak rateIs greater than the preset carrier gas leakage rate +.>And the third abnormal signal duration time T (4) is larger than the set signal minimum duration time T(s), and the abnormality of the primary gas path carrier gas conveying exists from the starting time Start (k) corresponding to the kth interval.

3. Starting from the k-e (0 < e < k) interval identified as abnormal carrier gas transportation of the primary gas path, judging whether the pressure of the gas flow monitoring device 1 on the primary gas path shows a descending trend or not, and judging whether the volume consumption of the carrier gas shows an ascending trend or not

(a) Starting from the Start time Start (k-e) corresponding to the k-e interval, using the formula ΔP _{First level} (i)＝P _{First level} (i+1)－P _{First level} (i) Calculating the pressure difference delta P at adjacent moments _{First level} (i)<0, and a duration T (5) when the above formula is established,

(b) Calculating from the k-e interval using the formula DeltaV _{First level} (k)＝V _{First level} (k+1)－V _{First level} (k)

Calculating the difference DeltaV of the volume consumption of adjacent sections _{First level} (k)>0, and a duration T (6) when the above formula is established,

if the pressure difference delta P is at adjacent time _{First level} <Duration T (5) of 0 and difference DeltaV between adjacent interval volume consumption _{First level} >And if the duration T (6) of 0 is larger than the set signal minimum duration T(s), the pressure on the primary gas circuit is considered to be reduced, and the volume consumption is considered to be increased.

4. Starting from the k-e (0 < e < k) interval identified as abnormal carrier gas transportation of the primary gas circuit, judging whether the pressure of the gas flow monitoring device (numbered 2-N) on the secondary gas circuit shows a descending trend, and judging whether the volume consumption of the carrier gas shows the descending trend, wherein the condition can be met after the data on 1 monitoring device is calculated:

(c) Starting from the Start time Start (k-e) corresponding to the k-e interval, using the formula ΔP _Second-level (i)＝P _Second-level (i+1)－P _Second-level (i) Calculating the pressure difference delta P at adjacent moments _Second-level (i)<0, and a duration T (7) when the above formula is established,

(d) Calculating from the k-e interval using the formula DeltaV _Second-level (k)＝V _Second-level (k+1)－V _Second-level (k) Calculating the difference DeltaV of the volume consumption of adjacent sections _Second-level (k)<0, and a duration T (8) when the above formula is established,

if the pressure difference delta P is at adjacent time _Second-level <Duration T (7) of 0 and difference DeltaV between adjacent interval volume consumption _Second-level <And if the duration time T (8) of 0 is larger than the set signal minimum duration time T(s), the pressure on the secondary gas circuit is considered to be reduced, and the volume consumption is considered to be reduced.

Judging condition II: and judging whether the change trend of the pressure and the volume consumption of the primary gas circuit and the change trend of the pressure and the volume consumption of any one gas flow monitoring device (numbered 2-N) of the secondary gas circuit meet the requirements.

In summary, only if the above 2 leakage characteristics are satisfied at the same time, it can be judged that leakage occurs between the primary air channel and the secondary air channel, otherwise, it can be judged as suspected leakage.

Judging the leakage condition between the first-stage gas circuit and the second-stage gas circuit based on the first leakage rate, comprising the following steps: if the first leakage rate is greater than a preset leakage threshold value, acquiring a third abnormal signal duration; if the duration of the third abnormal signal is larger than the preset time threshold, judging that carrier gas conveying abnormality exists between the first-stage gas circuit and the second-stage gas circuit.

Referring to fig. 5, fig. 5 is a schematic diagram of a dynamic volume balance based gas chromatograph leak monitoring response system according to an embodiment of the present invention.

In one embodiment, a dynamic volume balance based gas chromatograph leak monitoring response system includes: the gas flow monitoring device is used for acquiring a flow measurement value of the carrier gas on the secondary gas circuit, a total flow measurement value of the carrier gas at the sample inlet end of the gas chromatograph, a flow measurement value of the carrier gas at the detector end of the gas chromatograph and a second correction value of the carrier gas in a pipeline between the secondary gas circuit and the gas chromatograph; the volume unbalance item calculation module is in communication connection with the gas flow monitoring device, and calculates a secondary volume unbalance item according to a flow measurement value of the carrier gas on the secondary gas path, a total flow measurement value of the carrier gas at the sample inlet end, a flow measurement value of the carrier gas at the detector end and a second correction value based on a dynamic volume balance method; the average value calculation module is used for obtaining to-be-processed data with the time length of one frame being T flow signals and calculating a second average value based on the to-be-processed data; the leakage judging module is in communication connection with the volume unbalance item calculating module and the average value calculating module and is used for calculating a second leakage rate between the second gas circuit and the gas chromatograph according to the second volume unbalance item and the second average value and judging the leakage condition between the second gas circuit and the gas chromatograph based on the second leakage rate.

Further, the dynamic volume balance based gas chromatograph leak monitoring response system further comprises: the response module is in communication connection with the leakage judging module and is used for generating corresponding control instructions according to the type of the leakage gas and the leakage condition.

The response module can automatically perform corresponding processing according to the leakage judgment result, does not need a technician to manually close an air source on site under the condition of dangerous gas hydrogen leakage, and can automatically and timely stop the supply of hydrogen on a primary air path or a secondary air path, so that the gas chromatograph and the technician using the gas chromatograph are prevented from being in dangerous environments, and the technician is also allowed to remotely operate and control, so that the technician can work safely, efficiently and conveniently.

The memory, as a non-transitory computer readable storage medium, may be used to store non-transitory software programs as well as non-transitory computer executable programs. In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory optionally includes memory remotely located relative to the processor, the remote memory being connectable to the processor through a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The above described apparatus embodiments are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, i.e. may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

Furthermore, an embodiment of the present invention provides a computer-readable storage medium storing computer-executable instructions that are executed by a processor or controller, for example, by one of the processors in the above-described terminal embodiment, and cause the processor to perform the dynamic volume balance-based gas chromatograph leakage monitoring method in the above-described embodiment.

Those of ordinary skill in the art will appreciate that all or some of the steps, systems, and methods disclosed above may be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on computer readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). The term computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data, as known to those skilled in the art. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer. Furthermore, as is well known to those of ordinary skill in the art, communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media.

While the preferred embodiment of the present invention has been described in detail, the present invention is not limited to the above embodiment, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are included in the scope of the present invention as defined in the appended claims.

The above-described embodiments of the present invention do not limit the scope of the present invention. Any of various other corresponding changes and modifications made according to the technical idea of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A gas chromatograph leak monitoring method based on dynamic volume balance, comprising the steps of:

2. The dynamic volume balance based gas chromatograph leakage monitoring method of claim 1, wherein determining a leakage condition between a secondary gas circuit and the gas chromatograph based on the second leakage rate comprises the steps of:

3. The dynamic volume balance based gas chromatograph leakage monitoring method according to claim 2, characterized by comprising the steps of, after judging that there is a carrier gas transportation abnormality between the secondary gas path and the gas chromatograph:

4. The dynamic volume balance based gas chromatograph leakage monitoring method of claim 1, wherein the step of obtaining the second correction value of the carrier gas in the pipeline between the secondary gas circuit and the gas chromatograph comprises the steps of:

acquiring pressure P of starting point of secondary gas circuit pipeline ₁ And pressure at the end point P ₂ The internal diameter D of the pipeline, the hydraulic friction coefficient tau, the relative density rho of the carrier gas, the carrier gas compression factor Z, the gas temperature T and the pipeline length L are calculated to obtain the correction value v of the carrier gas volume per second in the standard-state secondary gas pipeline _{2 Standard} ：

5. The dynamic volume balance based gas chromatograph leakage monitoring method according to claim 2, characterized by comprising the steps of, after judging that there is a carrier gas transportation abnormality between the secondary gas path and the gas chromatograph:

extracting the method parameters of the GC on the current secondary gas path, inquiring all data consistent with the method parameters of the GC on the current secondary gas path in the current day in a historical database, and extracting V with the same time length as that in the first curve _{Second order f} And calculate V _{Second order f} At any timeAnd the second curve is changed, and whether leakage exists between the second gas circuit and the gas chromatograph is judged by judging the difference between the first curve and the second curve.

6. The dynamic volume balance based gas chromatograph leakage monitoring method according to claim 2, characterized by comprising the steps of, after calculating a secondary volume imbalance term of a secondary gas path carrier gas based on a dynamic volume balance method:

7. A gas chromatograph leak monitoring method based on dynamic volume balance, comprising the steps of:

8. The dynamic volume balance based gas chromatograph leakage monitoring method according to claim 7, characterized in that the leakage condition between the primary gas circuit and the secondary gas circuit is judged based on the first leakage rate, comprising the steps of:

9. A dynamic volume balance based gas chromatograph leak monitoring response system, wherein the dynamic volume balance based gas chromatograph leak monitoring method of any of claims 1-8 is applied, the system comprising:

10. The dynamic volume balance based gas chromatograph leak monitoring response system of claim 9, further comprising:

and the response module is in communication connection with the leakage judging module and is used for generating a corresponding control instruction according to the type of the leaked gas and the leakage condition.