CN110261188B

CN110261188B - Online alternative concentration and release device for smoke pollutants

Info

Publication number: CN110261188B
Application number: CN201910696852.1A
Authority: CN
Inventors: 潘登杲; 杨敬树; 章鹏飞; 张忠梅; 汤绍富; 尚凡杰
Original assignee: Zhejiang Fuchunjiang Environmental Technology Research Co ltd
Current assignee: Zhejiang Fuchunjiang Environmental Technology Research Co ltd
Priority date: 2019-07-30
Filing date: 2019-07-30
Publication date: 2024-03-22
Anticipated expiration: 2039-07-30
Also published as: CN110261188A

Abstract

An online alternating concentration and release device for flue gas pollutants belongs to the technical field of concentrated samples, and comprises an air source pipeline module, a water removal module, a first-stage enrichment and release module and a second-stage enrichment and release module which are sequentially connected; an eight-way valve, a first sampling well and a second sampling well are arranged in the first-stage enrichment and release module; two ends of the first sampling well and two ends of the second sampling well are connected with eight-way valves; the first sampling well and the second sampling well are alternately connected with the sample through the switching of the eight-way valve. The device adopts two-stage adsorption, the first stage uses a large-volume sampling cold trap to adsorb a large amount of substances, the second stage uses a small-volume focusing cold trap to overcome the defect that the components of target substances of the traditional smoke sampling device are too few, and meanwhile, the device is an alternating on-line concentration and release device, and can realize alternating enrichment of smoke pollutants, so that continuous sampling analysis is realized.

Description

Online alternative concentration and release device for smoke pollutants

Technical Field

The invention belongs to the technical field of concentrated samples, and particularly relates to an online alternating concentration and release device for flue gas pollutants.

Background

Currently, related technologies of garbage incineration utilization in China are widely applied, and the trend of high-speed development is still kept in the next 10 years. The problem of secondary pollutant emission caused by garbage incineration, especially the problem of dioxin emission, is also increasingly concerned by governments and people, and even becomes a troublesome problem which puzzles the whole processes of site selection, construction, operation and the like of many garbage incineration power generation projects.

According to about persistenceThe emission reduction control of dioxin is required by the Stockholm convention of sexual organic pollutants, and various emission sources in China must be effectively realized. Dioxins are trace-grade substances and have a concentration of typically 10 in flue gas ^-10 g/m ³ The concentration of the waste gas is accurately measured with high technical difficulty, and at present, most of detection methods for other flue gas pollutants except dioxin are mature, and the detection of the dioxin emission of the incinerator cannot realize on-line rapid detection.

At present, the main flow technology for detecting dioxin emission in incineration flue gas in China is an off-line detection technology. The technology depends on a dioxin measuring method specified in domestic garbage incineration pollution control standard (GB 18485-2014) and an isotope dilution high-resolution meteorological chromatography-high-resolution mass spectrometry method for measuring dioxins in ambient air and waste gas. The method adopts an off-line detection method combining on-site sampling with laboratory pretreatment and analysis test, and can provide accurate detection data for the measurement of the dioxin emission of the incinerator. The dioxin detection method comprises the steps of firstly sampling on site, then sending the sample to a national certified dioxin laboratory, purifying and the like, and performing off-line analysis by using a high-resolution gas chromatograph/high-resolution mass spectrometer (HRGC/HRMS); the measurement period is usually more than several weeks through a complicated sample pretreatment process. The method is time-consuming, expensive, and the test result has no guiding effect on operation, so that the method becomes an important constraint factor for comprehensively and effectively controlling the dioxin emission at present. In addition, the dioxin emission data of the garbage incinerator cannot be timely and accurately known, and an insurmountable technical obstacle is brought to government supervision and public supervision.

Based on the detection result, the rapid target and the demand of dioxin emission reduction are served, and the rapid and real-time online detection method, technology and equipment of dioxin are researched and developed, so that the rapid and real-time online detection method, technology and equipment of dioxin become one of main trends of trace and trace persistent organic pollutant detection and control development in the incineration process. The dioxin online detection technology has the advantages and effects of reflecting the concentration of dioxin in the flue gas online in real time, guiding the adjustment of combustion working conditions in the furnace and the optimization of flue gas purification parameters, assisting the research of the mechanism of the dioxin generation process and the like.

Because the existing analysis technology cannot realize direct detection of the dioxin, the current mainstream online detection technology route of the dioxin adopts detection of some intermediate substances (or precursor substances) which are relatively large in online concentration and are easy to detect and are determined to be related to the dioxin, so that the online concentration of the dioxin is evaluated. The concentration of the dioxin precursor in the flue gas is low, and the requirement on temperature is high. The indirect detection method is required to solve the problems of complex components, uneven concentration, high water content, complex sampling flow path and the like in the flue gas.

Therefore, the technical scheme is that the flue gas pollutant on-line alternating concentration and release device solves the above difficulties, so that the target pollutant in the flue gas can be concentrated, the impurity is less, and the loss is less and the target pollutant enters the detection system.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings and provide an on-line alternating concentration and release device for flue gas pollutants.

The technical scheme adopted by the invention for achieving the purpose is as follows.

An on-line alternating concentration and release device for flue gas pollutants comprises an air source pipeline module, a water removal module, a first-stage enrichment and release module and a second-stage enrichment and release module which are sequentially connected; an eight-way valve, a first sampling well and a second sampling well are arranged in the first-stage enrichment and release module; two ends of the first sampling well and two ends of the second sampling well are connected with eight-way valves; the first sampling well and the second sampling well are alternately connected with the sample through the switching of the eight-way valve.

The air source pipeline module comprises a blank pipeline, a standard air pipeline, a sampling pipeline, an anti-blowing pipeline and a sample injection switching valve; the sample injection switching valve is provided with a sample outlet, a back-blowing port and at least one sample injection port, wherein the back-blowing port is connected with the sample injection port; a first sample inlet of the sample switching valve is connected with a blank pipeline; the blank pipeline is connected with a blank source; the second sample inlet of the sample switching valve is connected with the gas marking pipeline; the gas marking pipeline is connected with a gas marking source; a third sample inlet of the sample switching valve is connected with a sampling pipeline; the sampling pipeline is connected with a sampling gun, and a heating filter is arranged on the sampling pipeline; a fourth sample inlet of the sample switching valve is reserved in a venting mode; the back blowing port of the sample injection switching valve is connected with a back blowing pipeline; the back-blowing air pipeline is connected with a back-blowing air source, and is provided with a first electromagnetic valve; and a sample outlet of the sample injection switching valve is connected with the water removal module.

The water removal module comprises a first four-way joint, a first emptying pipeline, a first six-way valve, a first water removal trap, a second six-way valve, a second water removal trap, a first carrier gas pipeline, a first tee joint valve and a second emptying pipeline;

the first four-way valve is provided with four connectors which are respectively connected with a sample injection switching valve of the air source pipeline module, a 1 st interface of the first six-way valve, a 1 st interface of the second six-way valve and a first emptying pipeline;

the first drain line is provided with a first MFC and a first drain pump;

the first six-way valve and the second six-way valve are respectively provided with 6 interfaces, namely a 1 st interface, a 2 nd interface, a 3 rd interface, a 4 th interface, a 5 th interface and a 6 th interface, and the two interfaces are in two states: when in the state A, the 1 st interface is communicated with the 6 th interface, the 2 nd interface is communicated with the 3 rd interface, and the 4 th interface is communicated with the 5 th interface; when in the B state, the 1 st interface is communicated with the 2 nd interface, the 3 rd interface is communicated with the 4 th interface, and the 5 th interface is communicated with the 6 th interface;

the 2 nd interface of the first six-way valve is connected with a first-stage enrichment and release module; the 3 rd interface pipeline of the first six-way valve is connected with one end of a first water trap, and the other end of the first water trap is connected with the 6 th interface of the first six-way valve; the 4 th interface pipeline of the first six-way valve is connected with a first three-way valve; the 5 th interface pipeline of the first six-way valve is connected with a first tee joint;

The 2 nd interface of the second six-way valve is connected with the first-stage enrichment and release module; the 3 rd interface pipeline of the second six-way valve is connected with one end of a second water trap, and the other end of the second water trap is connected with the 6 th interface of the second six-way valve; the 4 th interface pipeline of the second six-way valve is connected with the first three-way valve; the 5 th interface pipeline of the second six-way valve is connected with a first tee joint;

one end of the first carrier gas pipeline is connected with the first tee joint, the other end of the first carrier gas pipeline is connected with the second tee joint, and the first carrier gas pipeline is provided with a second electromagnetic valve;

the first tee joint is provided with three connectors which are respectively connected with a first carrier gas pipeline, a 5 th interface of a first six-way valve and a 5 th interface of a second six-way valve;

the second tee joint is provided with three connectors which are respectively connected with a carrier gas source, a first carrier gas pipeline and a second carrier gas pipeline;

the first three-way valve is connected with a 4 th interface of a first six-way valve, a 4 th interface of a second six-way valve and a second emptying pipeline;

the second emptying pipeline is provided with a first activated carbon pipe.

The first-stage enrichment release module further comprises a first three-way switching valve, a second carrier gas pipeline, a third emptying pipeline, a fourth emptying pipeline and a third activated carbon pipe;

The first three-way switching valve is provided with 3 interfaces, and comprises an A interface connected with the first six-way valve, a B interface connected with the second six-way valve and a C interface connected with the eight-way valve. The first three-way switching valve performs gas circuit switching (communication or blocking) by controlling an AC (alternating current) or a BC (alternating current).

The eight-way valve is provided with 8 ports, which have two states: when in the state A, the 1 st interface is communicated with the 7 th interface, the 2 nd interface is communicated with the 8 th interface, the 3 rd interface is communicated with the 5 th interface, and the 4 th interface is communicated with the 6 th interface; when in the B state, the 1 st interface is communicated with the 3 rd interface, the 2 nd interface is communicated with the 4 th interface, the 5 th interface is communicated with the 7 th interface, and the 6 th interface is communicated with the 8 th interface;

the 1 st port of the eight-way valve is connected with a third emptying pipeline; the 2 nd interface of the eight-way valve is connected with the first three-way switching valve; the 3 rd interface of the eight-way valve is connected with one end of the second sampling well; the 4 th interface of the eight-way valve is connected with the other end of the second sampling well; the 5 th interface of the eight-way valve is connected with a second carrier gas pipeline; the 6 th interface of the eight-way valve is connected with a second three-way switching valve; the 7 th interface of the eight-way valve is connected with one end of the first sampling well; the 8 th interface of the eight-way valve is connected with the other end of the first sampling well;

The third emptying pipeline is provided with a second MFC, a second activated carbon pipe and a second emptying pump;

the second carrier gas line includes a third MFC; one end of the third MFC is connected with the second tee joint, and the other end of the third MFC is connected with a 5 th interface of the eight-way valve;

the fourth emptying pipeline is provided with a third activated carbon tube.

The second-stage enrichment and release module comprises a third six-way valve, a fifth emptying pipeline, a fourth active carbon pipe, a focusing trap, a gas chromatography module and a transmission line;

the third six-way valve is provided with 6 interfaces: the 1 st interface is connected with the second three-way switching valve, the 2 nd interface is connected with the fifth evacuation pipeline, the 3 rd interface is connected with one end of the focusing trap, the 4 th interface is connected with the gas chromatographic module, the 5 th interface is connected with the transmission line, and the 6 th interface is connected with the other end of the focusing trap;

the third six-way valve has two states of A and B; when the valve is in the state A, the 1 st interface and the 6 th interface of the third six-way valve are communicated, the 2 nd interface and the 3 rd interface of the third six-way valve are communicated, and the 4 th interface and the 5 th interface of the third six-way valve are communicated; when the valve is in the B state, the 1 st interface and the 2 nd interface of the third six-way valve are communicated, the 3 rd interface and the 4 th interface of the third six-way valve are communicated, and the 5 th interface and the 6 th interface of the third six-way valve are communicated;

The gas chromatography module is connected with the transmission line;

the fifth emptying pipeline is provided with a fourth activated carbon pipe;

the transmission line is a quartz tube with an inner wall without filling, and the inner diameter is 0.25mm.

The device adopts two-stage adsorption, the first stage uses a large-volume sampling cold trap, can realize large-volume sampling and adsorb a large amount of substances, and the second stage uses a small-volume focusing cold trap to play a role in focusing, so that the defect that the components of target substances of the traditional smoke sampling device are too few is overcome, and meanwhile, the device is an alternating on-line concentration and release device, and can realize alternating enrichment of smoke pollutants, so that continuous sampling analysis is realized.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is a schematic diagram of the structure of the air supply line module;

FIG. 3 is a schematic diagram of a water removal module;

FIG. 4 is a schematic diagram of the structure of a first stage enrichment release module;

FIG. 5 is a schematic diagram of the structure of a second stage enrichment release module;

in the figure: the air source pipeline module 100, the blank pipeline 101, the blank source 102, the standard air pipeline 103, the standard air source 104, the sampling pipeline 105, the sampling gun 106, the blowback air pipeline 107, the blowback air source 108, the first electromagnetic valve 109, the sample injection switching valve 110, the heating filter 111,

The water removal module 200, the first four-way valve 201, the first drain line 202, the first MFC202a, the first drain pump 202b, the first six-way valve 203, the first water removal trap 204, the second six-way valve 205, the second water removal trap 206, the first carrier gas line 207, the second solenoid valve 207a, the first three-way valve 208, the second three-way valve 209, the carrier gas source 210, the first three-way valve 211, the second drain line 212, the first activated carbon tube 213, the second gas line,

The first stage enrichment release module 300, the first three-way switching valve 301, the eight-way valve 302, the first sampling trap 303, the second sampling trap 304, the second three-way switching valve 305, the second carrier gas line 306, the third MFC307, the third evacuation line 308, the second MFC309, the second evacuation pump 310, the fourth evacuation line 311, the second activated carbon tube 312, the third activated carbon tube 313, the third gas line,

A second stage enrichment release module 400, a third six-way valve 401, a fifth evacuation pipe 402, a focusing trap 403, a gas chromatography module 404, a transmission line 405, and a fourth activated carbon pipe 406.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

An on-line alternating concentration and release device for flue gas pollutants comprises a gas source pipeline module 100, a water removal module 200, a first-stage enrichment and release module 300 and a second-stage enrichment and release module 400 which are sequentially connected.

The air source pipeline module 100 comprises a blank pipeline 101, a standard air pipeline 103, a sampling pipeline 105, a back-blowing pipeline 107 and a sample injection switching valve 110; the sample injection switching valve 110 is provided with a sample outlet, a back-blowing port and at least one sample injection port, wherein the back-blowing port is connected with the sample injection port. Preferably, the sample injection switching valve 110 is provided with a sample outlet, a back-blowing port and four sample injection ports, and the number of sample injection ports communicated with the sample outlet is always one. In this embodiment, the sample switching valve 110 may be-1/4 inch fittings,4.0mm ports, valco common outlet selectors in Switzerland.

A first sample inlet of the sample switching valve 110 is connected with the blank pipeline 101; the blank pipe 101 is connected with a blank source 102. The blank pipe 101 is provided with a heat tracing band. The blank line 101 is heated to 180 ℃ with heat tracing. The blank source 102 is filled with nitrogen or argon.

A second sample inlet of the sample switching valve 110 is connected with the gas marking pipeline 103; the standard gas pipeline 103 is connected with a standard gas source 104. The label gas line 103 and label gas source 104 need to be heated to 180 ℃. The standard gas source 104 is used for calibration, and a standard curve is used for obtaining the concentration of the target substances in the smoke. The standard gas is the standard substance in a gaseous state.

A third sample inlet of the sample switching valve 110 is connected with the sampling pipeline 105; the sampling line 105 is connected with a sampling gun 106, and the sampling line 105 is equipped with a heating filter 111. The sampling line 105, sampling gun 106, heating filter 111 and sample switching valve 110 all need to be heated to 180 ℃.

The fourth sample port of the sample switching valve 110 is vented and reserved. The reserved sample inlet is reserved for standby and is used for introducing other smoke.

The back blowing port of the sample injection switching valve 110 is connected with a back blowing pipeline 107; the blowback air line 107 is connected with a blowback air source 108, and the blowback air line 107 is provided with a first solenoid valve 109.

The sample outlet of the sample injection switching valve 110 is connected with the water removal module 200.

The sample injection switching valve 110 switches different states, so that different gas sources can enter the subsequent instrument. The sample-in switching valve 110 allows the standard gas, sample, or blank gas to the water removal module 200.

The water removal module 200 comprises a first four-way joint 201, a first evacuation pipeline 202, a first six-way valve 203, a first water removal trap 204, a second six-way valve 205, a second water removal trap 206, a first carrier gas pipeline 207, a first tee joint 208, a first tee joint valve 211 and a second evacuation pipeline 212.

The first four-way valve 201 is provided with four connectors, which are respectively connected with the sample injection switching valve 110 of the gas source pipeline module 100, the 1 st interface of the first six-way valve 203, the 1 st interface of the second six-way valve 205, and the first evacuation pipeline 202.

The first drain line 202 is provided with a first MFC202a and a first drain pump 202b.

MFC, MASS FLOW CONTROLLER, i.e. mass flow controller.

The first evacuation line 202 is a main evacuation line for keeping the gas inside the device conduit in a flowing state at all times, avoiding a dead volume of the gas after a long residence time in the line.

The first six-way valve 203 and the second six-way valve 205 are respectively provided with 6 interfaces, namely a 1 st interface, a 2 nd interface, a 3 rd interface, a 4 th interface, a 5 th interface and a 6 th interface, which are arranged clockwise in the figure and have two states: when in the state A, the 1 st interface is communicated with the 6 th interface, the 2 nd interface is communicated with the 3 rd interface, and the 4 th interface is communicated with the 5 th interface; when in the B state, the 1 st interface is communicated with the 2 nd interface, the 3 rd interface is communicated with the 4 th interface, and the 5 th interface is communicated with the 6 th interface.

The 2 nd interface of the first six-way valve 203 is connected with the first-stage enrichment and release module 300;

the 3 rd interface pipeline of the first six-way valve 203 is connected with one end of the first water trap 204, and the other end of the first water trap 204 is connected with the 6 th interface of the first six-way valve 203;

the 4 th interface pipeline of the first six-way valve 203 is connected with a first three-way valve 211;

The 5 th port pipeline of the first six-way valve 203 is connected with a first tee joint 208.

The 2 nd interface of the second six-way valve 205 is connected with the first-stage enrichment and release module 300;

the 3 rd interface pipeline of the second six-way valve 205 is connected with one end of a second water trap 206, and the other end of the second water trap 206 is connected with the 6 th interface of the second six-way valve 205;

the 4 th interface pipeline of the second six-way valve 205 is connected with a first three-way valve 211;

the 5 th port pipeline of the second six-way valve 205 is connected with a first tee joint 208.

One end of the first carrier gas pipeline 207 is connected with the first tee joint 208, the other end is connected with the second tee joint 209, and the first carrier gas pipeline 207 is provided with a second electromagnetic valve 207a.

The first tee 208 is provided with three connectors, which are respectively connected with the first carrier gas pipeline 207, the 5 th interface of the first six-way valve 203 and the 5 th interface of the second six-way valve 205.

The second tee 209 is provided with three connectors, and is respectively connected with a carrier gas source 210, a first carrier gas pipeline 207 and a second carrier gas pipeline 306.

The first three-way valve 211 is connected with the 4 th port of the first six-way valve 203, the 4 th port of the second six-way valve 205 and the second evacuation line 212.

The second evacuation line 212 is provided with a first activated carbon tube 213.

The heat tracing belt is arranged on the pipeline between the first four-way valve 201 and the first six-way valve 203, the pipeline between the first six-way valve 203 and the first water trap 204 and the pipeline between the first water trap 204 and the first-stage enrichment and release module 300, and is heated by the heat tracing belt, and the heat is traced to 180 ℃.

The heat tracing belt is arranged on the pipeline between the first four-way valve 201 and the second six-way valve 205, the pipeline between the second six-way valve 205 and the second water trap 206 and the pipeline between the second water trap 206 and the first-stage enrichment and release module 300, and is heated by the heat tracing belt, and the heat is traced to 180 ℃.

When the water removal module 200 works, the states of the first six-way valve 203 and the second six-way valve 205 are opposite:

when the first six-way valve 203 is in the a state, the second six-way valve 205 is in the B state; at this time, a part of the standard gas or the sample gas from the gas source pipeline module 100 enters the 1 st port of the first six-way valve 203 through the first four-way valve 201, then enters the first water trap 204 from the 6 th port of the first six-way valve 203 to perform water removal operation, the first water trap 204 is in a low temperature state and is frozen for water removal, and the water is frozen into liquid or condensed; the standard gas or the sample gas subjected to the water removal treatment enters the 3 rd interface of the first six-way valve 203 and enters the first-stage enrichment and release module 300 from the 2 nd interface of the first six-way valve 203; part of the standard gas or sample gas enters the 1 st interface of the second six-way valve 205 through the first four-way valve 201, then enters the first-stage enrichment and release module 300 from the 2 nd interface of the second six-way valve 205 and is blocked, the channel is closed, and the gas cannot circulate;

Meanwhile, part of the carrier gas in the carrier gas source 210 passes through the second tee 209, the first carrier gas pipeline 207 and the first tee 208, and part of the carrier gas passes through the 5 th interface of the first six-way valve 203 and the 4 th interface of the first six-way valve 203 to reach the first tee 211; part of carrier gas passes through the 5 th interface of the second six-way valve 205, the 6 th interface of the second six-way valve 205 and the second water trap 206, is heated and dried to remove water, and then enters the second evacuation pipeline 212 from the 3 rd interface of the second six-way valve 205, the 4 th interface of the second six-way valve 205 and the first three-way valve 211 to be discharged; the second emptying pipeline 212 is provided with a first activated carbon pipe 213 for adsorbing pollutants and preventing the pollutants from being directly discharged into the air;

when the first six-way valve 203 is in the B state, the second six-way valve 205 is in the a state, and the first three-way switching valve 301 also switches the ventilation inlet; at this time, the standard gas or the sample gas from the gas source pipeline module 100 enters the 1 st port of the first six-way valve 203 through the first four-way valve 201, then enters the first stage enrichment and release module 300 from the 2 nd port of the first six-way valve 203 and is blocked, so that the channel is closed, and the gas cannot circulate; the standard gas or the sample gas from the gas source pipeline module 100 enters the 1 st interface of the second six-way valve 205 through the first four-way valve 201, then enters the second water trap 206 from the 6 th interface of the second six-way valve 205 for water removal operation, and the second water trap 206 is in a low-temperature state and freezes water, and the water is frozen into liquid or condensed; the standard gas or the sample gas subjected to the water removal treatment enters the 3 rd interface of the second six-way valve 205 and enters the first-stage enrichment and release module 300 from the 2 nd interface of the second six-way valve 205;

Meanwhile, the carrier gas in the carrier gas source 210 passes through the second tee 209, the first carrier gas pipeline 207 and the first tee 208, part of the carrier gas passes through the 5 th interface of the first six-way valve 203 and the 6 th interface of the first six-way valve 203 and then enters the first water trap 204, is heated and dried to remove water, and then enters the second evacuation pipeline 212 from the 3 rd interface of the first six-way valve 203, the 4 th interface of the first six-way valve 203 and the first tee 211 and is discharged; part of the carrier gas passes through the 5 th and 4 th ports of the second six-way valve 205 and then goes to the first three-way valve 211 for blocking.

Through setting up parallel water removal pipeline to rationally set up two six way valves, make two way water removal pipeline work in turn, that is to say, when one water removal trap is carrying out the water removal operation, another water removal trap then takes away unnecessary moisture through the carrier gas, is ready for its follow-up water removal operation.

Preferably, the inner diameter of the water trap is 3mm, no filler exists, and a deactivated quartz tube is adopted. The function is as follows: the small inner diameter is beneficial to the quick passing of substances and reduces the adsorption probability.

When water is removed, the water removing trap is in a low-temperature state; when back blowing, the water is changed into gas when the water trap is heated at high temperature and is taken away along with the carrier gas.

The first stage enrichment release module 300 comprises a first three-way switching valve 301, an eight-way valve 302, a first sampling trap 303, a second sampling trap 304, a second three-way switching valve 305, a second carrier gas pipeline 306, a third evacuation pipeline 308, a fourth evacuation pipeline 311 and a third activated carbon pipe 313.

The first three-way switching valve 301 is provided with 3 ports, including an a port connected with the first six-way valve 203, a B port connected with the second six-way valve 205, and a C port connected with the eight-way valve 302. The first three-way switching valve 301 performs switching (communication or blocking) of the gas path by controlling the AC or BC.

The eight-way valve 302 is provided with 8 ports, which have two states: when in the state A, the 1 st interface is communicated with the 7 th interface, the 2 nd interface is communicated with the 8 th interface, the 3 rd interface is communicated with the 5 th interface, and the 4 th interface is communicated with the 6 th interface; when in the B state, the 1 st interface is communicated with the 3 rd interface, the 2 nd interface is communicated with the 4 th interface, the 5 th interface is communicated with the 7 th interface, and the 6 th interface is communicated with the 8 th interface.

The 1 st port of the eight-way valve 302 is connected to a third evacuation line 308; the 2 nd interface of the eight-way valve 302 is connected with the first three-way switching valve 301; the 3 rd interface of the eight-way valve 302 is connected to one end of the second sampling well 304; the 4 th interface of the eight-way valve 302 is connected with the other end of the second sampling well 304; the 5 th port of the eight-way valve 302 is connected to a second carrier gas line 306; the 6 th interface of the eight-way valve 302 is connected with a second three-way switching valve 305; the 7 th interface of the eight-way valve 302 is connected with one end of the first sampling well 303; the 8 th interface of the eight-way valve 302 is connected to the other end of the first sampling well 303.

The third evacuation line 308 is provided with a second MFC309, a second activated carbon tube 312 and a second evacuation pump 310.

The gas passes through the water trap and power is required to enter the sampling trap. The third evacuation line 308 provides power for the gas in sampling, water removal, and enrichment.

The second carrier gas line 306 includes a third MFC307; one end of the third MFC307 is connected to the second tee 209, and the other end is connected to the 5 th port of the eight-way valve 302.

The first sampling well 303 and the second sampling well 304 are quartz tubes with built-in filler, and are wrapped with ceramic heating sleeves, and the ceramic heating sleeves are placed in a semiconductor refrigeration box and have the functions of low-temperature adsorption and high-temperature release.

The fourth evacuation pipe 311 is provided with a third activated carbon pipe 313, and adsorbs non-adsorbed gas to perform a filtering function.

When the evacuation is required, the gas is discharged through the fourth evacuation line 311, and the substances or moisture not adsorbed inside is removed through the third activated carbon pipe 313.

The pipeline between the first three-way switching valve 301 and the eight-way valve 302, the sample pipeline of the first sampling trap 303, the sample pipeline of the second sampling trap 304, and the pipeline between the eight-way valve 302 and the second three-way switching valve 305 are all provided with a heat tracing band, and the heat tracing band is used for heating to about 180 ℃.

When the eight-way valve 302 is in the state a, the standard gas or the sample gas conveyed by the water removal module 200 passes through the 2 nd interface and the 8 th interface of the eight-way valve 302, enters the first stage target object of the first sampling well 303 to be adsorbed, and the rest standard gas or the sample gas enters the third evacuation pipeline 308 from the 7 th interface and the 1 st interface of the eight-way valve 302 to be discharged.

Meanwhile, the carrier gas in the second carrier gas pipeline 306 enters the second sampling trap 304 through the 5 th interface and the 3 rd interface of the eight-way valve 302, brings the enriched concentrated gas in the second sampling trap 304 out, and then passes through the 4 th interface and the 6 th interface of the eight-way valve 302 to reach the second three-way switching valve 305;

when the eight-way valve 302 is switched to the state B, the standard gas or the sample gas conveyed by the water removal module 200 passes through the 2 nd interface and the 4 th interface of the eight-way valve 302, enters the second sampling well 304, the first-stage target object is adsorbed, and the rest standard gas or the sample gas enters the third evacuation pipeline 308 from the 3 rd interface and the 1 st interface of the eight-way valve 302 to be discharged;

meanwhile, the carrier gas in the second carrier gas pipeline 306 enters the first sampling trap 303 through the 5 th interface and the 7 th interface of the eight-way valve 302, brings the enriched concentrated gas in the first sampling trap 303 out, and then passes through the 8 th interface and the 6 th interface of the eight-way valve 302 to reach the second three-way switching valve 305;

The second three-way switching valve 305 is provided with 3 interfaces, which are respectively connected with the 6 th interface of the eight-way valve 302, the second-stage enrichment release module 400 and the fourth evacuation pipeline 311; the second three-way switching valve 305 delivers the carrier gas enriched in the first stage target to the second stage enrichment release module 400.

According to the technical scheme, through the switching of the eight-way valve 302, the first sampling well 303 and the second sampling well 304 are alternately adsorbed and released, so that the continuous concentration of the smoke pollutants is realized.

Communication of carrier gas source 210: the carrier gas source 210 is communicated with the first-stage enrichment and release module 300, and the carrier gas in the carrier gas source 210 flows through the first-stage enrichment and release module 300 and the second-stage enrichment and release module 400 and is discharged outside, so that the non-enriched matters (gas, particles and water) are blown away.

Preferably, the sampling well has an inner diameter of 1/4 inch. The large-volume sampling well is matched with the filler, so that more target substances can be collected, the concentration of the target substances is increased, and the analysis accuracy is improved.

The second stage enrichment release module 400 includes a third six-way valve 401, a fifth evacuation line 402, a fourth activated carbon tube 406, a focusing trap 403, a gas chromatography module 404, and a transmission line 405.

The third six-way valve 401 is provided with 6 ports: the 1 st interface is connected with the second three-way switching valve 305, the 2 nd interface is connected with the fifth evacuation pipeline 402, the 3 rd interface is connected with one end of the focusing trap 403, the 4 th interface is connected with the gas chromatography module 404, the 5 th interface is connected with the transmission line 405, and the 6 th interface is connected with the other end of the focusing trap 403.

The third six-way valve 401 has two states, a and B; when in the state A, the 1 st interface and the 6 th interface of the third six-way valve 401 are communicated, the 2 nd interface and the 3 rd interface of the third six-way valve 401 are communicated, and the 4 th interface and the 5 th interface of the third six-way valve 401 are communicated; when in the B state, the 1 st port and the 2 nd port of the third six-way valve 401 are communicated, the 3 rd port and the 4 th port of the third six-way valve 401 are communicated, and the 5 th port and the 6 th port of the third six-way valve 401 are communicated.

The gas chromatography module 404 is connected to a transmission line 405.

The fifth evacuation pipe 402 is provided with a fourth activated carbon pipe 406, which adsorbs non-adsorbed gas and performs a filtering function.

The transmission line 405 is a quartz tube with an inner wall having no filler, the inner diameter is 0.25mm, one end of the transmission line is connected with a 1/16 inch stainless steel tube at the outlet of the third six-way valve 401, and the other end of the transmission line is connected with the gas chromatography module 404, so that the effects of excessive connection and focusing are achieved.

The pipeline between the second three-way switching valve 305 and the third six-way valve 401, the sample pipeline of the focusing trap 403, and the pipeline between the third six-way valve 401 and the transmission line 405 are all provided with heat tracing bands, and the heat tracing bands are used for heating to about 180 ℃.

In the device, the carrier gas is nitrogen or helium-argon.

Preferably, the focusing trap 403 has a wide mouth and a thin mouth, and the sample is more fully diffused and more easily absorbed from the thin mouth to the wide mouth when the sample is focused. The sample is focused more sufficiently from wide mouth to thin mouth in the analysis, so that the analysis accuracy is improved. Still further, the wide mouth inner diameter of the focusing trap 403 is 3mm and the thin mouth inner diameter is 1.2mm.

At present, no online alternative concentration and release device for flue gas pollutants exists in the market, and the online concentration and release device for ambient air exists in the market, but the components of the ambient air pollutants are simple, the concentration of the interferents is low, the water content is low, and the temperature requirement of a sample collection flow path is low (the temperature of a general sampling pipeline is consistent with the original temperature of a sample). The smoke has complex components, so that adsorbed substances are many, and the analysis difficulty is increased. According to the technical scheme, corresponding substances are selectively adsorbed by multistage adsorption and different fillers.

The concentration of the smoke components is uneven, if a small volume is used for sampling the cold trap, the required target substance components are too little. The technical scheme changes the two-stage adsorption, the first stage uses a large-volume sampling cold trap to adsorb a large amount of first-stage targets, and the second stage uses a small-volume focusing cold trap to adsorb a small amount of second-stage targets.

The smoke has high water content, so that an instrument can be damaged, and the accuracy of a sample is greatly reduced. The technical scheme adopts the water removal module for freezing water removal, continuously removes water, and ensures the continuity of detection. The cold trap is frozen, enriched and concentrated, the optimal adsorption temperature of different substances is different, and the freezing, enriched and concentrated are used, so that the enrichment temperature range is wide, and the enrichment and concentration efficiency is improved.

The sampling flow path temperature requirement is high: the temperature of the sample sampling flow path is consistent with the original temperature of the sample, so that the organic matters are prevented from being adsorbed on the surface of the sampling tube due to low temperature. In the technical scheme, the sample flow path is controlled at about 180 ℃.

An on-line alternating concentration and release device for flue gas pollutants comprises the following using method:

s1, debugging of a working state: heating an air inlet pipeline and a valve body to 150-210 ℃; and starting the refrigeration state of the water removal module 200, and enabling the first water removal trap 204 and the second water removal trap 206 to reach the low temperature of minus 20 ℃ to 30 ℃.

In this scheme, because the high temperature flue gas is let in, consequently, need the sample maintain with high temperature flue gas the same temperature, prevent the condensation of high boiling point's component to the detection accuracy has been guaranteed.

Temperature control is an innovation point of the scheme. The collection of the ambient air can be realized only by the fact that the equipment flow path temperature is consistent with the ambient air source and a common electromagnetic valve. However, if the temperature of the flow path of the collected flue gas (180 ℃ for flue gas) is lower than the temperature of the air source, the target object can be adsorbed on the flow path.

The electromagnetic valve is internally provided with lubricating oil, a rubber ring and the like, and the lubricating oil and the rubber ring volatilize organic matters at high temperature to interfere detection. And the electromagnetic valve is easy to fail in a high-temperature working environment, so that the stability of the system is affected. In addition, the electromagnetic valve structure has dead volume, and a section always exists the dead volume.

Therefore, only the valve in the technical scheme can be used for collecting the smoke.

S2, exhaust gas in a device pipeline is discharged:

communication of the blank line 101: the blank pipeline 101 of the air source pipeline module 100 is communicated with the water removal module 200, the blank gas stored in the blank source 102 flows through the water removal module 200 and the first sampling well 303 and is discharged, whether the previous group of samples have residues is detected by blank sample injection, if residues exist, a plurality of groups of blanks are communicated or an instrument method is changed, and if no residues exist, the next group of samples are carried out. The blank sample injection is used for improving analysis accuracy, and is one of quality control means.

S3, measuring standard gas: the standard gas pipeline 103 of the gas source pipeline module 100 is communicated with the water removal module 200, and after the standard gas is subjected to water removal by the water removal module 200 and the first-stage target object enrichment of the first sampling trap 303, the residual standard gas is discharged; after the enriched target is heated and released, the enriched target flows into the second-stage enrichment and release module 400 along with carrier gas to carry out enrichment and adsorption of the second-stage target, and the rest first-stage target is discharged; finally, after the second-stage target is heated and released,

And then enters the gas chromatography module 404 for detection after passing through a transmission line 405.

S4, determination of a sample: the sampling pipeline 105 of the air source pipeline module 100 is communicated with the water removal module 200, and after the sample is subjected to water removal by the water removal module 200 and the first-stage target object enrichment of the first sampling trap 303, the rest sample is discharged; after the enriched target is heated and released, the enriched target flows into the second-stage enrichment and release module 400 along with carrier gas to carry out enrichment and adsorption of the second-stage target, and the rest first-stage target is discharged; finally, the second stage target is heated and released, and then enters the gas chromatography module 404 for detection after passing through the transmission line 405.

The water trap, the sampling trap, the focusing trap, the low temperature range (-20 ℃ to 30 ℃) and the temperature control precision of 1 ℃ are cooled by a semiconductor. The high temperature range (30-380 ℃) has the temperature control precision of 1 ℃, the high temperature is heated by a ceramic heating pipe, the heating temperature rising rate is more than 40 ℃/s, and the rapid temperature rising enables adsorbed substances to be released instantaneously during cold trap analysis.

Example 1:

the device is matched with a dioxin on-line detection system to measure the toxicity equivalent of dioxin in flue gas, and comprises the following steps:

the method realizes the alternate enrichment and release of the organic matters in the flue gas on line, and is matched with a dioxin on-line detection system to measure the toxicity equivalent of the dioxin in the flue gas, and the method comprises three steps: and the first step is to calibrate target substances (standard gases) and establish a standard fitting working curve. And the second step of actually detecting target substances in the flue gas, and the third step of converting the toxicity equivalent of the dioxin through a correlation model.

Heating an air source and a sampling module pipeline:

in order to avoid the loss of the target detection substance due to condensation and adsorption in the process of flowing through the pipeline and influence the accuracy of the detection result, the gas source, the pipeline through which the gas path flows in the sampling process and the valve body are heated. When the calibration is carried out, the heating flow of each part is as follows:

1. and (3) opening a standard gas storage tank (a Suma tank) and heating a blank (high-purity nitrogen) storage tank, wherein the temperature reaches a set value of 180 ℃, and a heating pipeline is wrapped by a heat tracing belt from the tank body of the Suma tank to a dehydration module 1 and a No. 2 six-way valve of a flue gas organic matter alternate enrichment and release device.

2. The cooling function of the water removal module 200 is started, and the temperature of the water removal module is reduced to-10 ℃ by using a semiconductor refrigerating device.

3. Starting a first-stage enrichment and release module 300 of a sample in the flue gas organic matter alternating enrichment and release device; all of the lines in the sample second stage enrichment and release module 400 gas sampling flow path and the valve body heat.

4. The gas chromatography module 404 was turned on and the carrier gas flow rate was turned on to adjust the carrier gas flow rate to 2mL/min. And starting the dioxin on-line detection system.

The target substance standard gas calibration is carried out, and a standard fitting working curve is established, wherein the steps are as follows:

1. the valve of the standard gas storage tank is opened, the sample injection switching valve 110 is adjusted to enable the standard gas pipeline 103 to be communicated with the water removal module 200, the first MFC202a is opened to control the flow rate of gas entering the main pipeline, and the first emptying pump 202b is opened to provide suction. The main first MFC202a flow rate was regulated at 50mL/min. The main way is designed to switch different sampling sources and ensure that the gas in the sampling pipeline always circulates under the condition of sampling gaps, so that dead volume is prevented from being generated, namely static volume is prevented from being generated.

2. The standard gas passing through the gas source pipeline module 100 enters the water removal module 200. The water removal module 200 sets the chilled low temperature to-10 c with the first water removal trap 204 and the second water removal trap 206 operating alternately. The first water trap 204 corresponds to a first sampling trap 303, and the second water trap 206 corresponds to a second sampling trap 304.

3. The target gas enters the first sampling well 303.

When the standard gas passes through the water removal module 200 and then enters the first sampling well 303, the temperature of the first sampling well 303 is set to 30 ℃, and the target substance is adsorbed by the filler filled in the first sampling well 303. The sampling flow rate is controlled by the second MFC309, and the second evacuation pump 310 is powered. The sampling flow rate is 10ml/Min, and the sampling time is 15Min.

4. The first sampling well 303 blowbacks.

The back-flushing flow rate is controlled by the third MFC307, and the carrier gas (Ar) in the gas storage tank acts as back-flushing gas, and the substances (gas, liquid, solid) that are not adsorbed in the back-flushing line and the first sampling trap 303. The purpose of the back flushing of the path improves the purity of the collected substances and reduces the interference of other substances. The back flushing flow rate was 50 ml/Min and the back flushing time was 2Min.

5. The adsorbed material of the first sampling well 303 is thermally desorbed into the focusing well 403.

The first sampling trap 303 is heated to 300 c (heating time 20 s) while the third MFC307 is turned on and the flow rate is adjusted to blow back 50 ml/Min for a period of 5Min, taking the adsorbed species through the first sampling trap 303 into the focusing trap 403. The focus trap 403 temperature is 30 ℃.

6. Focusing trap 403 heating resolution

The focusing trap 403 was heated to 300 ℃ (heating time was 5 s) while switching the third six-way valve 401, and carrier gas (Ar) was introduced at 2ml/min for 5min, flowing through the focusing trap 403, carrying away the adsorbed material into the capillary chromatographic column passing through the gas chromatography module 404. The transmission line 405 connecting the focusing trap 403 and capillary column is connected by a 1/16 inch inside diameter transition 1/32 inch (inside diameter 0.25 mm) hollow column for the purpose of focusing function (from thick inside diameter to thin inside diameter).

The first dewatering trap 204, the second dewatering trap 206, the first sampling trap 303 and the second sampling trap 304, and the focusing trap 403 alternately sample, dewater, dry blow and analyze, so that blank-free, full-coverage and real-time sampling are realized.

7. Gas chromatographic separation

The material released through the focusing trap 403 is separated by a chromatographic column of the gas chromatography module 404 into a subsequent detection system.

And (3) introducing standard gas storage tanks with different concentration gradients (0.5 ppb,2ppb,4ppb,6ppb,8ppb and 10 ppb) into a sampling pipeline module, and switching a sampling valve to sample. The flow rate is 10mL/min, the time is 15min, and the total volume of 150mL is collected. The target object standard gas of each volume concentration is subjected to repeated measurement for 6 times, and the detection results are respectively input into the data acquisition device through the signal input end of the data acquisition device to display data.

According to the steps, each volume concentration and the detection result corresponding to each concentrationDrawing a working curve, then fitting according to a least square method to obtain a regression equation Y=ax+b of a standard working curve, and performing fitting calculation to obtain the standard working curve: a=0.0011, b=0.0012, r ² 0.9675, i.e. standard fitting working curve y=0.0011x+0.0012.

Detection limit

Formula (VI)The calculation method detects the limit MDL. Method detection limit 0.11ppb

Concentration ratio

And collecting target substances through the flue gas organic matter alternative enrichment and release device and directly introducing the target substances into the dioxin on-line detection device. The ratio of the two is the concentration ratio of the flue gas organic matter alternate enrichment and release device.

Drawing a working curve according to detection results corresponding to different sampling volumes, then fitting according to a least square method to obtain a regression equation Y=ax+b of a standard working curve, and performing fitting calculation to obtain the standard working curve: a=0.01446, b= -0.1685, r ² 0.9988, i.e. standard fitting working curve y= 0.1446x-0.1685.

Accuracy of

Accuracy: 8.8%

Precision (relative standard deviation): 2.3%

24 hour concentration drift

And under the normal working state of the instrument, 10ppb standard gas is introduced, the average value of the measured concentration of the instrument to be measured is calculated for 6 times continuously, after the ventilation is finished, the analysis instrument to be measured continuously runs for 24 hours (no maintenance and calibration is allowed in the period), the operation is repeated, and the average value of the measured concentration of 3 times after 24 hours is calculated.

The 24h concentration drifts 0.4ppb at a target gas concentration of 10 ppb.

Drying tube water removal performance.

10ppb, moisture content 22% in 180 ℃ flue gas, and mixing test of the Suma tank and standard gas which are configured at 180 ℃ and have different moisture contents.

The moisture content is 30% and below, the standard gas loss of the water removal device is less than 15%, but the standard gas loss of the water removal device is 61% under the condition of 10% of the moisture content. The water removal device is necessary for high humidity flue gas testing.

The present embodiment describes the present technical solution by using the detection of dioxin, and it is worth noting that the present technical solution is not limited to the detection of dioxin, but is also applicable to the detection of other gases.

The eight-way valve 302 is a two-position eight-way valve commercially available, and for example, two-position eight-way valve in chinese patent application publication No. CN105938130a can be used.

According to the technical scheme, through reasonable arrangement of the pipelines, the air inlet directions of the water trap and the sampling trap are opposite to the air reverse blowing direction, so that the air reverse blowing effect is improved.

The invention has been described in terms of embodiments, and the device can be modified and improved without departing from the principles of the invention. It should be noted that all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. The online alternating concentration and release device for the flue gas pollutants is characterized by comprising an air source pipeline module (100), a water removal module (200), a first-stage enrichment and release module (300) and a second-stage enrichment and release module (400) which are sequentially connected; an eight-way valve (302), a first sampling well (303) and a second sampling well (304) are arranged in the first-stage enrichment and release module (300); two ends of the first sampling well (303) and two ends of the second sampling well (304) are connected with eight-way valves (302); the first sampling well (303) and the second sampling well (304) are alternately communicated with the sample through the switching of the eight-way valve (302);

the air source pipeline module (100) comprises a blank pipeline (101), a standard air pipeline (103), a sampling pipeline (105), a back blowing pipeline (107) and a sample injection switching valve (110); the sample injection switching valve (110) is provided with a sample outlet, a back blowing port and at least one sample injection port, wherein the back blowing port is connected with the sample injection port; a first sample inlet of the sample injection switching valve (110) is connected with the blank pipeline (101); the blank pipeline (101) is connected with a blank source (102); a second sample inlet of the sample injection switching valve (110) is connected with the standard gas pipeline (103); the standard gas pipeline (103) is connected with a standard gas source (104); a third sample inlet of the sample switching valve (110) is connected with the sampling pipeline (105); the sampling pipeline (105) is connected with a sampling gun (106), and the sampling pipeline (105) is provided with a heating filter (111); a fourth sample inlet of the sample switching valve (110) is reserved in a venting mode; a back blowing port of the sample injection switching valve (110) is connected with a back blowing pipeline (107); the back-flushing air pipeline (107) is connected with a back-flushing air source (108), and the back-flushing air pipeline (107) is provided with a first electromagnetic valve (109); the sample outlet of the sample injection switching valve (110) is connected with the water removal module (200);

The water removal module (200) comprises a first four-way joint (201), a first emptying pipeline (202), a first six-way valve (203), a first water removal trap (204), a second six-way valve (205), a second water removal trap (206), a first carrier gas pipeline (207), a first three-way joint (208), a first three-way valve (211) and a second emptying pipeline (212);

the first four-way valve (201) is provided with four connectors which are respectively connected with a sample injection switching valve (110) of the air source pipeline module (100), a 1 st interface of the first six-way valve (203), a 1 st interface of the second six-way valve (205) and a first emptying pipeline (202);

the first drain line (202) is provided with a first MFC (202 a) and a first drain pump (202 b);

the first six-way valve (203) and the second six-way valve (205) are respectively provided with 6 interfaces, namely a 1 st interface, a 2 nd interface, a 3 rd interface, a 4 th interface, a 5 th interface and a 6 th interface, and the two interfaces are in two states: when in the state A, the 1 st interface is communicated with the 6 th interface, the 2 nd interface is communicated with the 3 rd interface, and the 4 th interface is communicated with the 5 th interface; when in the B state, the 1 st interface is communicated with the 2 nd interface, the 3 rd interface is communicated with the 4 th interface, and the 5 th interface is communicated with the 6 th interface;

The 2 nd interface of the first six-way valve (203) is connected with a first-stage enrichment and release module (300); the 3 rd interface pipeline of the first six-way valve (203) is connected with one end of a first water trap (204), and the other end of the first water trap (204) is connected with the 6 th interface of the first six-way valve (203); the 4 th interface pipeline of the first six-way valve (203) is connected with a first three-way valve (211); the 5 th interface pipeline of the first six-way valve (203) is connected with a first tee joint (208);

the 2 nd interface of the second six-way valve (205) is connected with the first-stage enrichment and release module (300); the 3 rd interface pipeline of the second six-way valve (205) is connected with one end of a second water trap (206), and the other end of the second water trap (206) is connected with the 6 th interface of the second six-way valve (205); the 4 th interface pipeline of the second six-way valve (205) is connected with a first three-way valve (211); the 5 th interface pipeline of the second six-way valve (205) is connected with a first tee joint (208);

one end of the first carrier gas pipeline (207) is connected with a first tee joint (208), the other end of the first carrier gas pipeline is connected with a second tee joint (209), and the first carrier gas pipeline (207) is provided with a second electromagnetic valve (207 a);

the first tee joint (208) is provided with three connectors which are respectively connected with a first carrier gas pipeline (207), a 5 th interface of the first six-way valve (203) and a 5 th interface of the second six-way valve (205);

The second tee joint (209) is provided with three connectors, and is respectively connected with a carrier gas source (210), a first carrier gas pipeline (207) and a second carrier gas pipeline (306);

the first three-way valve (211) is connected with a 4 th interface of the first six-way valve (203), a 4 th interface of the second six-way valve (205) and a second emptying pipeline (212);

the second emptying pipeline (212) is provided with a first activated carbon pipe (213);

the first-stage enrichment release module (300) further comprises a first three-way switching valve (301), a second three-way switching valve (305), a second carrier gas pipeline (306), a third emptying pipeline (308), a fourth emptying pipeline (311) and a third activated carbon pipe (313);

the first three-way switching valve (301) is provided with 3 interfaces, including an A interface connected with the first six-way valve (203), a B interface connected with the second six-way valve (205) and a C interface connected with the eight-way valve (302);

the first three-way switching valve (301) performs gas circuit switching by controlling an AC (alternating current) or a BC (alternating current) channel;

the eight-way valve (302) is provided with 8 ports, which have two states: when in the state A, the 1 st interface is communicated with the 7 th interface, the 2 nd interface is communicated with the 8 th interface, the 3 rd interface is communicated with the 5 th interface, and the 4 th interface is communicated with the 6 th interface; when in the B state, the 1 st interface is communicated with the 3 rd interface, the 2 nd interface is communicated with the 4 th interface, the 5 th interface is communicated with the 7 th interface, and the 6 th interface is communicated with the 8 th interface;

The 1 st port of the eight-way valve (302) is connected with a third emptying pipeline (308); the 2 nd interface of the eight-way valve (302) is connected with the first three-way switching valve (301); the 3 rd interface of the eight-way valve (302) is connected with one end of the second sampling well (304); the 4 th interface of the eight-way valve (302) is connected with the other end of the second sampling well (304); the 5 th interface of the eight-way valve (302) is connected with a second carrier gas pipeline (306); the 6 th interface of the eight-way valve (302) is connected with a second three-way switching valve (305); the 7 th interface of the eight-way valve (302) is connected with one end of the first sampling well (303); the 8 th interface of the eight-way valve (302) is connected with the other end of the first sampling well (303);

the third evacuation line (308) is provided with a second MFC (309), a second activated carbon tube (312) and a second evacuation pump (310);

the second carrier gas line (306) comprises a third MFC (307); one end of the third MFC (307) is connected with the second tee joint (209), and the other end of the third MFC is connected with a 5 th interface of the eight-way valve (302);

the fourth emptying pipeline (311) is provided with a third activated carbon pipe (313);

the second-stage enrichment release module (400) comprises a third six-way valve (401), a fifth emptying pipeline (402), a fourth active carbon pipe (406), a focusing trap (403), a gas chromatography module (404) and a transmission line (405);

The third six-way valve (401) is provided with 6 interfaces: the 1 st interface is connected with a second three-way switching valve (305), the 2 nd interface is connected with a fifth emptying pipeline (402), the 3 rd interface is connected with one end of a focusing well (403), the 4 th interface is connected with a gas chromatography module (404), the 5 th interface is connected with a transmission line (405), and the 6 th interface is connected with the other end of the focusing well (403);

the third six-way valve (401) has two states, a and B; when the valve is in the state A, the 1 st interface and the 6 th interface of the third six-way valve (401) are communicated, the 2 nd interface and the 3 rd interface of the third six-way valve (401) are communicated, and the 4 th interface and the 5 th interface of the third six-way valve (401) are communicated; when the valve is in the B state, the 1 st interface and the 2 nd interface of the third six-way valve (401) are communicated, the 3 rd interface and the 4 th interface of the third six-way valve (401) are communicated, and the 5 th interface and the 6 th interface of the third six-way valve (401) are communicated;

the gas chromatography module (404) is connected with a transmission line (405);

the fifth evacuation pipe (402) is provided with a fourth activated carbon pipe (406);

the transmission line (405) is a quartz tube with an inner wall free of filler, and the inner diameter is 0.25mm.