CN115436113A - Volatile organic compound sampling analysis method and system - Google Patents
Volatile organic compound sampling analysis method and system Download PDFInfo
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- CN115436113A CN115436113A CN202211070573.2A CN202211070573A CN115436113A CN 115436113 A CN115436113 A CN 115436113A CN 202211070573 A CN202211070573 A CN 202211070573A CN 115436113 A CN115436113 A CN 115436113A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2247—Sampling from a flowing stream of gas
- G01N1/2258—Sampling from a flowing stream of gas in a stack or chimney
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/24—Suction devices
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
Abstract
The application relates to the field of volatile substance sampling analysis, in particular to a volatile organic substance sampling analysis method, which comprises the following steps: vacuumizing the sampling bottle; fixing a sampling gun on the side wall of the exhaust passage, and inserting a sampling end into the exhaust passage; connecting the sampling bottle to a connecting port of a sampling gun; the sampling bottle is communicated with the sampling gun, and a sample to be collected in the exhaust passage is discharged into the sampling bottle under the action of negative pressure; after sampling for a set duration, taking the sampling bottle off the sampling gun, and sealing the sampling bottle; and connecting the sampling bottle to a detection device to perform detection analysis on the sample. The method and the device have the effects of reducing inconvenience caused by sampling and analyzing processes and improving detection efficiency and accuracy.
Description
Technical Field
The application relates to the field of volatile substance sampling analysis, in particular to a volatile organic substance sampling analysis method and system.
Background
VOC detection is an important part in environmental pollution detection, detects environmental quality through each item data, the result that VOC detected, confirms whether mill discharges and accords with standard, whether environmental quality satisfies normal life requirement etc. for example to the mill of production class, especially relate to the factory area of burning, generally all can set up the pipe of discharging fume that is used for discharging the flue gas, whether to the flue gas that discharges accords with the standard that purification treatment discharged, need carry out sample analysis to the flue gas that discharges.
At present, the smoke discharged from a smoke exhaust channel is sampled and analyzed by a sampling gun, the sampling is carried out by a vacuum bag, namely, the sampling bag is arranged in a closed box body, the opening of the sampling bag is positioned outside the closed box body and is in a closed state, when the sampling is carried out, a vacuumizing machine is used for vacuumizing the closed box body to be in a vacuum (negative pressure) state, and the opening of the sampling bag is connected with the sampling gun; when the sampling is started, the sampling bag is communicated with the sampling gun, the sampling of the smoke in the exhaust channel is realized through the pressure difference, and after the sampling is completed, the sampling bag is transported to a detection room and other places for analysis, so that the sample is analyzed.
With respect to the related art in the above, the inventors found that: the sampling bag is used for sampling, a closed box and corresponding vacuum-pumping equipment are matched, so that the sampling operation is complex, and meanwhile, when a plurality of sampling bags are used for sampling, when one sampling bag is used for sampling and a new sampling bag is replaced, the sampling bag is inconvenient to replace, so that inconvenience is caused to a normal sampling process; after accomplishing the sample, carry the sample bag from the sampling area to the detection room and carry out the analysis, overall efficiency is lower, and because the restriction of sample bag sampling, the time of preserving is shorter, and long-time preservation, transportation cause the error to the testing result because of appearing leaking or sample composition and reacting easily, have and cause more inconvenient problem for normal sampling, analytic process.
Disclosure of Invention
In order to reduce inconvenience caused to the sampling and analyzing processes and improve the detection efficiency and accuracy, the application provides a volatile organic compound sampling and analyzing method and a volatile organic compound sampling and analyzing structure.
In a first aspect, the method for sampling and analyzing volatile organic compounds provided by the present application adopts the following technical scheme:
a volatile organic compound sampling analysis method comprises the following steps:
vacuumizing the sampling bottle;
fixing a sampling gun on the side wall of the exhaust channel, and inserting a sampling end into the exhaust channel;
connecting the sampling bottle to a connecting port of a sampling gun;
the sampling bottle is communicated with the sampling gun, and a sample to be collected in the exhaust passage is discharged into the sampling bottle under the action of negative pressure;
after sampling is continued for a set time, the sampling bottle is taken down from the sampling gun, and the sealing of the sampling bottle is realized;
and connecting the sampling bottle to a detection device to perform detection analysis on the sample.
By adopting the technical scheme, the sampling bottle is used for sampling, compared with a mode of putting the sampling bag into a vacuum closed box for sampling, the integral structure is simpler and more convenient, and meanwhile, when the container needs to be replaced in the sampling process, the sampling bottle is directly pulled out of the sampling gun and replaced by a new sampling bottle; the storage time that can prolong the sample, realize the storage of longer time, and at the in-process of storage, be difficult to appear the problem that sample wherein leaked, can have more sufficient time to transport and follow-up analysis, detect, be difficult to appear when carrying out the detection analysis to the sample has appeared that the sample has partial leakage or the sample in wait to detect the material and react and lead to the problem of concentration change, consequently, reduce and lead to the problem that the testing result appears the deviation, the testing result is more accurate, the repetitive work that need carry out the sampling once more when also having reduced the sample and appearing leaking the scheduling problem.
Optionally, before the sampling bottle is connected to the sampling gun for sampling, residual gas in the sampling gun is extracted and replaced by gas to be detected in the exhaust channel, and then the sampling bottle is connected to the sampling gun for sampling.
Through adopting above-mentioned technical scheme, reduce the condition that appears remaining gas in the sampling rifle and collected to the sampling bottle, be difficult to so cause the influence because of this part residual gas is to the concentration of gathering the volatile organic compounds in the sample, reduce the unsafe problem of testing result that appears, promote the measurement accuracy.
Optionally, the amount of extracted gas is measured in the process of extracting residues in the sampling gun, when the amount of extracted gas reaches a first set value, the sampling rate of the sampling bottle is adjusted to a set rate, and the ventilation path is adjusted to enable the sampling bottle to be communicated with the sampling gun for sampling.
Through adopting above-mentioned technical scheme, set for first setting value and slightly be greater than remaining gas volume in the sampling rifle, when guaranteeing that the gas exhaust that will remain in the sampling rifle is clean, reduce the gas in the too much exhaust passage of discharge, be difficult to cause the influence to the concentration of the volatile organic compounds of the sample of gathering, also reduced the problem that causes the pollution to the surrounding environment.
Optionally, in the process of collecting the sample, the pressure value in the sampling bottle is maintained within the set pressure.
By adopting the technical scheme, the condensation phenomenon of the moisture in the sample is reduced in the follow-up process of storing and transporting the sampling bottle, the influence on the concentration of the volatile organic compounds of the sample is reduced, and the accuracy of the follow-up measuring result is improved.
Optionally, the set rate of the object to be sampled entering the sampling bottle in the sampling process is determined according to the set pressure and the set duration, the size of the communication path between the sampling bottle and the sampling gun is adjusted, and the flow rate of the object to be sampled entering the sampling bottle from the sampling gun is limited to be maintained at the set rate.
By adopting the technical scheme, the speed of the sampling bottle for collecting the samples is maintained at the set rate, the duration time of the sampling process reaches the set duration, and the collected samples have enough representativeness; meanwhile, the pressure in the sampling bottle is ensured not to exceed the set pressure, and the problem that the concentration of volatile organic compounds in the sample is influenced by the condensation of moisture in the sample is reduced.
Optionally, when a sample in the sampling bottle is detected, a sample with a first set volume is extracted and introduced into the detection equipment;
obtaining the detection concentration of the volatile organic compounds of the sample, performing multiple concentration on the sample when the detection concentration is less than a first set threshold value, performing multiple dilution on the sample when the detection concentration is greater than the first set threshold value, and adjusting the concentration of the volatile organic compounds in the sample to be at the first set threshold value;
and introducing the sample with the concentration of the volatile organic compounds at the first set threshold value into detection equipment for detection.
Through adopting above-mentioned technical scheme, to the sample of unknown concentration, extract a small amount of samples and measure after the check out test set dilutes, reduce the problem that sample concentration is too high and cause the damage to check out test set, also be difficult for remaining because of the too high concentration and cause the influence to the degree of accuracy of follow-up testing result, detect the concentration of obtaining in advance of sample, concentrate or dilute the sample, make the volatile organic compounds concentration of sample maintain at first set threshold value, can promote the precision of testing result to a certain extent.
Optionally, when detecting samples in a plurality of sampling bottles, the sampling end of the detection device is sequentially connected with the plurality of sampling bottles to realize sample injection;
before the sampling bottle and the check out test set intercommunication detected the sample, heating sampling bottle makes in the sampling article temperature rise to the settlement temperature.
By adopting the technical scheme, when samples in different sampling bottles are detected, the sampling ends of the detection equipment are respectively connected with the corresponding sampling bottles, and compared with the mode that a plurality of existing sampling containers are directly connected with the sampling equipment through a multi-way valve, the problem of cross contamination in the process of introducing different samples into the detection equipment is reduced, and the problem of change of the concentration of volatile organic compounds of the samples is reduced; in addition, the sample in the sampling bottle is heated, and under the condition that partial water is condensed into liquid water in the sampling bottle, the partial liquid water is vaporized to form gas by heating, and the gas is transmitted to the detection equipment along with the sample to be detected, so that the problem that partial liquefied water is remained in the sampling bottle and cannot be transmitted to the detection equipment is reduced, the problem that the detection result of the sample has errors is reduced, and the precision of the detection result is improved.
In a second aspect, the present application further discloses a volatile organic compound sampling analysis system, which adopts the following technical scheme:
a volatile organic compound sampling analysis system comprises a sampling gun, a sampling device and a control device, wherein the sampling gun is inserted into an exhaust channel to guide out smoke in the exhaust channel, and the end part of the sampling gun, which is positioned outside the exhaust channel, is connected with a changeover plug;
the sampling bottle is internally vacuum, is connected to the adapter plug and is connected with the sampling gun through the adapter plug so as to sample the smoke in the exhaust channel;
the air extraction assembly is connected to the adapter plug and is used for extracting and replacing the gas in the sampling gun into the to-be-sampled smoke in the exhaust channel;
the adapter plug is connected with a flowmeter.
Through adopting above-mentioned technical scheme, during the sampling, directly fix the sampling rifle on exhaust passage, use the subassembly of bleeding to take out the residual gas in with the sampling rifle, later install the sampling bottle and sample on the adapter connector, the sampling process is comparatively convenient, in addition, when installing, tearing open the change the sampling bottle, compare in prior art with the mode of installing the sample bag in a box that is vacuum state, it is also more convenient to operate, improves work efficiency.
Optionally, the sampling device further comprises a flow limiting valve, wherein the flow limiting valve is installed at a connector which is used for connecting the sampling bottle on the adapter plug, and the flow limiting valve is used for adjusting the flow of the flue gas which is introduced into the sampling bottle by the sampling gun.
By adopting the technical scheme, the speed of collecting the sample is conveniently adjusted, so that the sampling time reaches the set time, and the representativeness of the collected sample is improved.
Optionally, a sampling plug for connecting with the adapter plug is connected to the sampling bottle, and a pressure sensor is arranged at one end of the sampling plug, which is located in the sampling bottle;
the platform department that detection equipment is used for placing the sampling bottle sets up the heating module that is used for heating the sampling bottle.
By adopting the technical scheme, the pressure of the sample in the sampling bottle is measured, so that the pressure is maintained within the set pressure, the problem of condensation of water in the sample is reduced, and the problem of change of the concentration of volatile organic compounds influencing the sample is reduced; heating module through setting up heats the sampling bottle, has the phenomenon of remaining liquid water in the reduction sampling bottle, reduces to cause the stereo set to final testing result's precision, promotes the precision that this sampling analysis system detected.
In summary, the present application includes at least one of the following beneficial technical effects:
1. the sampling bottle is used for sampling, the whole structure is simple, the sampling operation process is simplified, and the working efficiency is higher; the storage time of the sample can be prolonged, the problem that the sample has partial leakage or the concentration changes due to the reaction of a substance to be detected in the sample when the sample is detected and analyzed is not easy to occur, the problem that the detection result has deviation is reduced, the detection result is more accurate, and the repeated work of sampling again when the sample has the problems of leakage and the like is reduced;
2. for a sample with unknown concentration, a small amount of sample is extracted to the detection equipment for measurement after dilution, the problem that the detection equipment is damaged due to overhigh concentration of the sample is reduced, the influence on the accuracy of a subsequent detection result due to the residue of overhigh concentration is not easy to occur, and after the pre-detection concentration of the sample is obtained through detection, the sample is concentrated or diluted, so that the concentration of the volatile organic compounds of the sample is maintained at a first set threshold value, and the accuracy of the detection result can be improved to a certain extent.
Drawings
FIG. 1 is a schematic diagram of an overall volatile organic sampling system according to an embodiment of the present application;
FIG. 2 is a schematic view showing a connection structure of a filter housing and a sampling gun;
FIG. 3 is a schematic view showing a connection structure of a sampling bottle and a sampling gun;
fig. 4 is a schematic flow chart of a method for sampling and analyzing volatile organic compounds according to an embodiment of the present application.
Description of reference numerals: 1. an exhaust passage; 2. a sampling gun; 21. a filter shell; 211. air holes; 212. a plug-in part; 22. a patch plug; 23. a flow-limiting valve; 24. a flow meter; 3. sampling bottles; 31. a sampling plug; 4. an air extraction assembly; 41. an air pump; 42. a purification component.
Detailed Description
The present application is described in further detail below with reference to figures 1-4.
The embodiment of the application discloses a volatile organic compound sampling analysis system, referring to fig. 1, the sampling analysis system comprises a sampling gun 2 inserted into an exhaust passage 1, a sampling bottle 3 connected to the end part of the sampling gun 2 outside the exhaust passage 1, and an air exhaust assembly 4 connected with the sampling gun 2, wherein the inside of the sampling bottle 3 is in a vacuum state; when sampling, fix sampling rifle 2 on exhaust passage 1's lateral wall, 2 one ends of sampling rifle are inserted to exhaust passage 1, will bleed subassembly 4 and connect on sampling rifle 2, use and bleed subassembly 4 and take out and replace the residual gas in sampling rifle 2 for the flue gas of treating in exhaust passage 1, later connect sampling bottle 3 at sampling rifle 2 and be located the outer tip of exhaust passage 1, adjust sampling bottle 3 and 2 intercommunications of sampling rifle, the flue gas through the effect of negative pressure drive in the exhaust passage 1 is arranged to sampling bottle 3 in, realize the sampling operation, later shift sampling bottle 3 to the check out test set that the room used to correspond and detect, the analysis.
Sampling is carried out through setting up sampling bottle 3, compare in the mode of putting into the vacuous closed box of sample bag and carrying out the sampling, holistic structure is comparatively simple and convenient, and simultaneously, when the container need be changed in the sampling process, directly pull out sampling bottle 3 from sampling rifle 2 and change new sampling bottle 3 can, compare in taking out the sample bag from the vacuum box and installing new sample bag to the vacuum box in and carry out the mode of evacuation again, the operation process of sampling has been simplified, work efficiency is higher.
The sampling bottle 3 is used for sampling, compared with a used sampling bag, the storage time of a sample can be prolonged, the storage for a longer time is realized, the problem of sample leakage is not easy to occur in the storage process, more sufficient time can be provided for transportation, subsequent analysis and detection, the problem of concentration change caused by partial leakage of the sample or reaction of partial components in the sample is not easy to occur when the sample is detected and analyzed, the problem of deviation of a detection result caused by the partial leakage of the sample is reduced, the detection result is more accurate, and the repeated work of sampling again when the problems of sample leakage and the like are solved; before carrying out the sampling operation, use air exhaust component 4 to take out residual gas in with sampling gun 2, can reduce the phenomenon that appears with remaining gas suction in sampling gun 2 in the sampling bottle 3, reduce the problem that causes the sample concentration of collection to change.
Referring to fig. 1 and 2, a filtering shell 21 is installed at one end of the sampling gun 2 inserted into the exhaust passage 1, a plurality of air holes 211 are formed in the filtering shell 21 to ensure normal ventilation, and the filtering shell 21 is used for placing filtering fillers, such as glass wool, metal fiber cotton net and ceramic fiber; in the sampling process, the collected sample is filtered by arranging the filter filler filled in the filter shell 21, so that the problem of particle impurities in the collected sample can be reduced, the problems of blockage and damage to the internal structure and the ventilation pipeline of the sampling gun 2 are reduced, in addition, the collected sample is not required to be filtered again in the subsequent detection and analysis, the detection and analysis can be directly carried out, the subsequent operation flow is simplified, and the problem of damage to equipment is not easy to occur; in other embodiments, a filter element may be disposed at any position between the communication paths of the sampling gun 2 and the sampling bottle 3, so as to filter the collected sample.
In addition, referring to fig. 2, in order to facilitate replacement of the filter filler, an end of the filter housing 21 facing the sampling gun 2 is provided with an opening, and an insertion portion 212 is integrally formed at the open end of the filter housing 21, and the insertion portion 212 is inserted into the opening of the sampling gun 2 in the exhaust passage 1 and is in threaded connection with the sampling gun 2; when the filter filling material needs to be replaced, the filter shell 21 can be directly unscrewed to replace the filter filling material, the operation is convenient, and the filter shell 21 can be directly replaced when the filter shell 21 is damaged.
Referring to fig. 1 and 3, one end of the sampling gun 2, which is located outside the exhaust passage 1, is connected with an adapter plug 22, the adapter plug 22 is connected with a flow limiting valve 23, the sampling bottle 3 is installed on the flow limiting valve 23, and the flow rate of the flue gas introduced into the sampling bottle 3 is adjusted through the flow limiting valve 23; air exhaust component 4 is connected on adapter plug 22, in order to can be comparatively convenient use air exhaust component 4 take out the gas in sampling gun 2, use sampling bottle 3 to sample and change between two kinds of operations, adapter plug 22 has the function of adjusting different routes, and specific reference is the principle of the used multi-ported valve in relevant field, and the manual regulation or electromagnetic control all can be selected during the in-service use.
In order to reduce the problem of condensation of moisture in the sample in the state that the sample is stored in the sampling bottle 3, the pressure in the sampling bottle 3 needs to be kept within a set pressure, so that the problem of concentration change of the sample caused by condensation of the moisture in the sample can be reduced; for the determination of the set pressure value, the determination is performed by combining various factors such as the humidity of the sample, the stored temperature, the type of the sample components, etc., and how to obtain the set pressure according to various data is well known by those skilled in the art according to the prior art and the operation flow, and therefore, the details are not described herein again; meanwhile, in the sampling process, in order to ensure that the sample has enough representativeness, the sampling process needs to be continued for a certain time so as to reduce the problem of poor representativeness of the collected sample, and the time is determined as the set time length; according to the set pressure and the set time length and the volume of the sampling bottle 3, the set speed of the sampling can be obtained, in the sampling process, the flow of the flow limiting valve 23 is set to be maintained at the set speed, and after the set time length of continuous sampling is obtained, the pressure of the sample in the sampling bottle 3 is maintained at the set pressure or is less than the set pressure, so that the representativeness of the collected sample is improved to the maximum extent, and the problem of errors of the detection result is reduced.
Referring to fig. 3, in order to connect the sampling bottle 3 to the flow limiting valve 23, a sampling plug 31 is fixed on the sampling bottle 3, the sampling plug 31 is directly inserted into the flow limiting valve 23, and when the sampling bottle 3 is installed, the sampling plug 31 is directly inserted into the flow limiting valve 23, so that the operation is convenient; meanwhile, a pressure sensor is arranged at one end of the sampling plug 31, which is positioned in the sampling bottle 3, so that the pressure of the sample in the sampling bottle 3 is detected in real time in the sampling process, and the sampling process is stopped after the pressure exceeds the set pressure, thereby further reducing the phenomenon that the pressure of the sample in the sampling bottle 3 exceeds the set pressure; sampling plug 31 is connected through the mode of inserting soon with sampling bottle 3, and it and take sampling plug 31 back from sampling bottle 3 out, and sampling bottle 3 directly closes sealedly, need not carry out additional operation and handles, and is comparatively convenient during the use, has reduced sealed untimely problem that causes the pollution to the sample purity.
Referring to fig. 1, the air pumping assembly 4 includes an air pump 41, a purifying member 42 is disposed between the air pump 41 and the adaptor plug 22, the purifying member 42 is an activated carbon filter, and the air pump 41, the activated carbon filter and the sampling gun 2 are sequentially connected through a vent pipe; when air suction pump 41 bleeds, purify through activated carbon filter, can reduce the problem that causes the damage to air suction pump 41, in addition, the gas that air suction pump 41 was taken out is directly arranged to the atmosphere, carries out certain purification through activated carbon filter, can reduce to appear taking partial flue gas out and directly arrange the problem that causes the pollution in the atmosphere.
In addition, referring to fig. 1 and 3, a flow meter 24 is connected to the adaptor plug 22 for measuring the volume of the flue gas passing through the adaptor plug 22, and when the gas remaining in the sampling gun 2 is pumped out using the suction pump 41, the volume of the pumped gas is measured so that the volume of the pumped gas reaches a first set value, which is slightly greater than the volume of the gas remaining in the sampling gun 2, thereby reducing the influence of the exhausted flue gas on the surrounding environment while ensuring that the residual gas is completely pumped out.
When examining, the connected mode to sampling bottle 3 and check out test set's sample end, cross contamination's problem appears in the convenience of connecting and reducing, it is direct to set up the sample end and is connected through the mode of pegging graft with sampling bottle 3, when carrying out the detection and analysis to the sample in a plurality of sampling bottles 3, the sample end is connected with sampling plug 31 on a plurality of sampling bottles in proper order, comparatively conveniently carry out the sample detection, and simultaneously, compare in the mode that current multi-way valve is connected with a plurality of sampling container simultaneously, cross contamination's problem appears between the different samples has been reduced, be difficult to cause the influence to the accuracy of sample testing result.
After accomplishing the sampling a period of time, deposit, shift sampling bottle 3's in-process, the problem that condensation appears in the partial moisture in sampling bottle 3 may exist, it is difficult to carry the sample to the check out test set completely in the follow-up sample transfer transport to check out test set in, therefore, be provided with heating module on check out test set is used for placing sampling bottle 3's platform, a sample for in to sampling bottle 3 heats, make liquefied moisture revaporization, can detect in the whole transmission of sample to check out test set in sampling bottle 3, reduce the problem that the concentration of the volatile organic compounds that leads to detecting appears the deviation because of the moisture in the sample that detects reduces, promote the accuracy of testing result.
The embodiment of the application also discloses a volatile organic compound sampling analysis method, and with reference to fig. 4, the sampling analysis method mainly comprises the following steps:
the preparation work in advance is carried out, the sampling bottle 3 is vacuumized, the filter filling is filled in the filter shell 21, the filter shell 21 is fixed at the end part of the sampling gun 2, and the air exhaust assembly 4 is connected to the sampling gun 2.
The sampling gun 2 is fixed on the exhaust passage 1, and one end of the sampling gun 2 where the filter shell 21 is located is inserted into the exhaust passage 1.
The air is extracted by using the air extracting pump 41, the residual gas in the sampling gun 2 is discharged and the residual gas is replaced by the smoke in the exhaust channel 1, and in the air extracting process of the air extracting pump 41, the volume of the extracted gas is monitored by the flowmeter 24, so that the amount of the extracted gas is slightly larger than the volume of the residual gas in the sampling gun 2, and therefore the phenomenon that more smoke is discharged to the outside is not easy to occur while the residual gas in the sampling gun 2 is completely discharged and the concentration of volatile organic compounds influencing the collected sample is changed, and the problem of pollution is reduced.
Connect sampling bottle 3 on restriction valve 23, combine the volume of the flue gas that the sampling bottle 3 was stored to obtain according to the volume of setting for pressure and sampling bottle 3, obtain the setting rate that sampling bottle 3 collected the sample according to the length of setting for that lasts the sampling in addition, adjust the flow of restriction valve 23 for the flue gas in the exhaust passage 1 is discharged to sampling bottle 3 in with the setting rate.
The sampling process is continuously set for a long time, and meanwhile, the pressure in the sampling bottle 3 is detected by combining with the arranged pressure sensor, so that the pressure of the sample in the sampling bottle 3 is kept within the set pressure; therefore, in the subsequent transportation and storage processes, the problem of condensation of the moisture in the sample is not easy to occur, and the concentration of the volatile organic compounds in the sample is not easy to change.
The sampling bottle 3 is transported to a detection and analysis device for detection, sampling is carried out through a sampling end on the detection device, and the sampling bottle 3 is heated through a heating module before sampling, so that liquid water possibly existing in the sampling bottle 3 is vaporized, and the subsequent complete transportation to the detection device along with the sample is facilitated; the method comprises the following steps of (1) introducing a sample in a sampling bottle 3 into a detection device to perform an analysis process, wherein during sampling detection, in order to improve the accuracy of a detection result to the maximum extent, the concentration of volatile high organic matters to be analyzed in the sample is kept at a first set threshold, wherein the first set threshold is determined by the type and the accuracy of the detection device and different detection objects, and for a person skilled in the art, the first set threshold can be obtained according to the existing corresponding relation, so that the description is omitted; under the condition that the approximate concentration of the volatile organic compounds of the sample is obtained in advance, the sample is concentrated and diluted according to a certain proportion, and the concentration is adjusted to a first set threshold value; the manner in which the sample concentration is adjusted: for the high-concentration sample, adopting small-volume sample injection, and for the low-concentration sample, adopting large-volume sample injection; the problem that the equipment is damaged due to overhigh concentration is not easy to occur, and the problem that the detection result is low in accuracy due to overlow concentration is also not easy to occur.
For a sample with completely unknown concentration, firstly, a sample with a first set volume is extracted and introduced into a detection device when detection is carried out, the first set volume is a smaller value, the sample is diluted according to a certain proportion when the sample is introduced into the detection device for detection, the approximate concentration of the corresponding volatile organic compounds in the sample is detected, then the sample is diluted or concentrated according to the proportion, and the concentration of the volatile organic compounds to be detected in the sample is maintained within a first set threshold value.
In addition, in the process of detecting and analyzing the samples, if the samples in the sampling bottles 3 need to be detected, the sampling ends of the detection equipment are sequentially connected with the sampling sockets on the sampling bottles 3; in the actual operation process, the sampling bottle 3 can be set to be in a standing state, the sampling end of the detection equipment is moved to be sequentially connected with the plurality of sampling bottles 3, or the sampling end of the detection equipment is in a standing state, and the sampling bottles 3 are moved to enable the plurality of sampling bottles 3 to be sequentially connected with the sampling end of the detection equipment; so, compare in the scheme that current a plurality of sampling containers pass through the multi-way valve and be connected with sampling equipment simultaneously, reduced the problem that cross contamination appears between a plurality of sampling containers, be difficult to cause the influence to the degree of accuracy of testing result.
The implementation principle of a volatile organic compound sampling analysis system in the embodiment of the application is as follows: when sampling the flue gas in the exhaust passage 1, firstly fixing the sampling gun 2 on the exhaust passage 1, inserting one end with the filter shell 21 into the exhaust passage 1, completely pumping the gas remained in the sampling gun 2 by using the air pump 41, then connecting the sampling bottle 3 with the interior in a vacuum state on the flow limiting valve 23, determining the value of the set rate according to the set pressure and the set duration, adjusting the flow of the flow limiting valve 23, continuously sampling the sampling bottle 3, taking off the sampling bottle 3 to complete the sampling operation after the duration reaches the set duration, and finally conveying the collected sample to the analysis equipment for detection and analysis.
The sampling bottle 3 is matched with the sampling gun 2 for sampling, so that the operation flow of sampling is simplified, and particularly, compared with a sampling mode using a sampling bag, the sampling method is more convenient under the condition that the sampling bottle 3 needs to be replaced in the sampling process; in addition, the flow limiting valve 23 is arranged, so that the sample collection rate of the sampling bottle 3 can be adjusted, the sampling duration can reach the set duration when the sample pressure in the sampling bottle 3 is not higher than the set pressure, the collected sample has better representativeness, and the problem that the final detection result has errors is not easy to occur.
Through using sampling bottle 3 to sample, compare in the sample bag that uses, can prolong the save time of sample, realize the storage of longer time, and at the in-process of storage, be difficult to appear the problem that sample wherein leaks, can have more sufficient time to transport and follow-up analysis, detect, be difficult to appear when carrying out the detection and analysis to the sample has appeared that the sample has partial leakage or wait to detect the material in the sample and react and lead to the problem of concentration change, reduce consequently and lead to the problem that the deviation appears in the testing result, the testing result is more accurate, the problem of the repetitive work that needs to sample again when also having reduced the sample and appearing leaking the scheduling problem.
The above are preferred embodiments of the present application, and the scope of protection of the present application is not limited thereto, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.
Claims (10)
1. A volatile organic compound sampling analysis method is characterized by comprising the following steps:
vacuumizing the sampling bottle (3);
fixing a sampling gun (2) on the side wall of the exhaust channel (1) and inserting a sampling end into the exhaust channel (1);
a connecting port for connecting the sampling bottle (3) to the sampling gun (2);
the sampling bottle (3) is communicated with the sampling gun (2), and a sample to be collected in the exhaust passage (1) is discharged into the sampling bottle (3) under the action of negative pressure;
after sampling is continuously carried out for a set time, the sampling bottle (3) is taken down from the sampling gun (2), and the sampling bottle (3) is sealed;
and connecting the sampling bottle (3) to a detection device to perform detection analysis on the sample.
2. The method for sampling and analyzing volatile organic compounds according to claim 1, wherein: before the sampling bottle (3) is connected to the sampling gun (2) for sampling, residual gas in the sampling gun (2) is extracted and replaced into gas to be detected in the exhaust channel (1), and then the sampling bottle (3) is connected to the sampling gun (2) for sampling.
3. The method for sampling and analyzing volatile organic compounds according to claim 2, wherein: the method comprises the steps of measuring the amount of extracted gas in the residual extraction process of a sampling gun (2), adjusting the sampling rate of a sampling bottle (3) to a set rate when the amount of extracted gas reaches a first set value, and adjusting a ventilation path to enable the sampling bottle (3) to be communicated with the sampling gun (2) for sampling.
4. A method for sampling and analyzing volatile organic compounds according to claim 3, characterized in that: in the process of collecting the sample, the pressure value in the sampling bottle (3) is maintained within the set pressure.
5. The method for sampling and analyzing volatile organic compounds according to claim 4, wherein: the method comprises the steps of determining a set rate of discharging an object to be sampled into a sampling bottle (3) in a sampling process according to a set pressure and a set duration, adjusting the size of a communication path between the sampling bottle (3) and a sampling gun (2), and limiting the flow rate of the object to be sampled discharged into the sampling bottle (3) from the sampling gun (2) to be maintained at the set rate.
6. The method according to claim 1, wherein the method further comprises: when a sample in the sampling bottle (3) is detected, a sample with a first set volume is extracted and introduced into detection equipment;
obtaining the detection concentration of the volatile organic compounds of the sample, performing multiple concentration on the sample when the detection concentration is less than a first set threshold value, performing multiple dilution on the sample when the detection concentration is greater than the first set threshold value, and adjusting the concentration of the volatile organic compounds in the sample to be at the first set threshold value;
and introducing the sample with the concentration of the volatile organic compounds at the first set threshold value into detection equipment for detection.
7. The method for sampling and analyzing volatile organic compounds according to claim 6, wherein: when samples in the sampling bottles (3) are detected, the sampling end of the detection equipment is sequentially connected with the sampling bottles (3) to realize sample introduction;
before the sampling bottle and the check out test set intercommunication detected the sample, heating sampling bottle makes in the sampling article temperature rise to the settlement temperature.
8. A volatile organic compounds sampling analytic system which characterized in that: comprises that
The sampling gun (2) is inserted into the exhaust channel (1) to guide out the smoke in the exhaust channel (1), and the end part of the sampling gun (2) positioned outside the exhaust channel (1) is connected with a changeover plug (22);
the sampling bottle (3) is internally vacuum, is connected to the adapter plug (22), and is connected with the sampling gun (2) through the adapter plug (22) to sample the flue gas in the exhaust passage (1);
and the air exhaust assembly (4) is connected to the adapter plug (22) and is used for exhausting the gas in the sampling gun (2) and replacing the gas with the to-be-sampled smoke in the exhaust channel (1).
9. The volatile organic compound sampling and analyzing system of claim 8, wherein: the sampling device is characterized by further comprising a flow limiting valve (23), wherein the flow limiting valve (23) is installed at a connector which is used for connecting the sampling bottle (3) on the adapter plug (22), and the flow limiting valve (23) is used for adjusting the flow of smoke which enters the sampling bottle (3) from the sampling gun (2).
10. The volatile organic compound sampling and analyzing system of claim 8, wherein: a sampling plug (31) used for being connected with the adapter plug (22) is connected to the sampling bottle (3), and a pressure sensor is arranged at one end, located in the sampling bottle (3), of the sampling plug (31);
the platform that the check out test set is used for placing sampling bottle (3) sets up the heating module that is used for heating sampling bottle (3).
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117309510A (en) * | 2023-11-28 | 2023-12-29 | 北京博赛德科技有限公司 | VOC pollution source remote sampling system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117309510A (en) * | 2023-11-28 | 2023-12-29 | 北京博赛德科技有限公司 | VOC pollution source remote sampling system |
| CN117309510B (en) * | 2023-11-28 | 2024-03-08 | 北京博赛德科技有限公司 | VOC pollution source remote sampling system |
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