A detection system for non-methane total hydrocarbons and benzene series

Abstract

The invention provides a detection system for non-methane total hydrocarbons and benzene series, and relates to the technical field of environmental monitoring. The system comprises: a fourteen-way valve, a plurality of chromatographic columns, a plurality of quantitative loops and an FID detector, wherein the fourteen-way valve is respectively connected with the plurality of chromatographic columns and the plurality of quantitative loops, and the plurality of chromatographic columns are connected with the FID detector; the fourteen-way valve is used for accessing sample gas and carrier gas, and sending quantitative sample gas into the plurality of chromatographic columns through the quantitative loops and the carrier gas, and after the quantitative determination is completed, the quantitative sample gas is discharged; the plurality of quantitative loops are used for storing the quantitative sample gas; the plurality of chromatographic columns are used for separating non-methane total hydrocarbons and / or benzene series in the quantitative sample gas, and sending the separated quantitative sample gas into the FID detector; the FID detector is used for detecting the separated quantitative sample gas, and determining the content of non-methane total hydrocarbons and the content of benzene series in the sample gas, thereby solving the technical problems of complex structure and high cost of the existing detection system.

Description

Technical Field

[0001] The invention relates to the technical field of environmental monitoring, and in particular to a detection system for non-methane total hydrocarbons and benzene series. Background Art

[0002] In recent years, people have become increasingly concerned about environmental quality issues. The country's monitoring of environmental air quality has become more comprehensive. The air pollutant standards promulgated by various industries have made clear requirements for the emissions of non-methane total hydrocarbons and benzene series, and technical standards and monitoring methods for continuous monitoring systems of fixed source exhaust gas have been introduced.

[0003] At present, the online continuous monitoring systems that meet the national standards for monitoring non-methane hydrocarbons and benzene series in volatile organic compounds in China are often based on the structure principle of multiple valves, multiple columns, and multiple detectors, such as: double valve, three columns, single detector structure or three valves, five columns, double detector structure. This type of structure can realize continuous monitoring of the concentration of non-methane hydrocarbons and benzene series through gas path connection, but its complex gas path structure and numerous components make maintenance and inspection inconvenient, and it is difficult to locate faults during the application of the equipment. The application of online continuous monitoring systems is costly, technically complex, and has a high risk of failure, which is not conducive to daily maintenance.

[0004] There is no effective solution to the above problems. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a detection system for non-methane total hydrocarbons and benzene series, so as to alleviate the technical problems of the existing detection system having a complex structure and high cost.

[0006] In a first aspect, an embodiment of the present invention provides a detection system for non-methane total hydrocarbons and benzene series, comprising: a fourteen-way valve, multiple chromatographic columns, multiple quantitative loops and an FID detector, wherein the fourteen-way valve is respectively connected to the multiple chromatographic columns and the multiple quantitative loops, and the multiple chromatographic columns are connected to the FID detector; the fourteen-way valve is used to connect sample gas and carrier gas, and to send the quantitative sample gas into the multiple chromatographic columns through the quantitative loops and the carrier gas, and to discharge the quantitative sample gas after the quantification is completed; the multiple quantitative loops are used to store the quantitative sample gas; the multiple chromatographic columns are used to separate the non-methane total hydrocarbons and / or benzene series in the quantitative sample gas, and to send the separated quantitative sample gas into the FID detector; the FID detector is used to detect the separated quantitative sample gas to determine the content of non-methane total hydrocarbons and the content of benzene series in the sample gas.

[0007] Furthermore, the multiple quantitative rings include: a first quantitative ring and a second quantitative ring, wherein the first quantitative ring is respectively connected to port 7 and port 14 of the fourteen-way valve, and the second quantitative ring is respectively connected to port 3 and port 6 of the fourteen-way valve.

[0008] Furthermore, the multiple chromatographic columns include: a first methane chromatographic column, a first benzene series chromatographic column, a first total hydrocarbon chromatographic column and a pre-column, wherein the first methane chromatographic column is respectively connected to port 9 of the fourteen-way valve and the FID detector, the first benzene series chromatographic column is respectively connected to port 11 of the fourteen-way valve and the first total hydrocarbon chromatographic column, the first total hydrocarbon chromatographic column is connected to port 5 of the fourteen-way valve, and the pre-column is respectively connected to port 10 of the fourteen-way valve and port 13 of the fourteen-way valve.

[0009] Furthermore, the carrier gas includes: a first carrier gas, a second carrier gas and a third carrier gas; port No. 1 of the fourteen-way valve is used to connect the sample gas; port No. 2 of the fourteen-way valve is used to discharge the sample gas after completing the quantification; port No. 4 of the fourteen-way valve is used to connect the second carrier gas; port No. 8 of the fourteen-way valve is used to connect the first carrier gas; port No. 12 of the fourteen-way valve is used to connect the third carrier gas.

[0010] Furthermore, the system further comprises: a six-way valve, wherein the six-way valve is respectively connected to the fourteen-way valve, the multiple chromatographic columns and the FID detector, and the multiple chromatographic columns are connected to the FID detector.

[0011] Furthermore, port No. 5 of the six-way valve is connected to port No. 8 of the fourteen-way valve; and port No. 2 of the six-way valve is connected to the FID detector.

[0012] Furthermore, the multiple chromatographic columns include: a second methane chromatographic column, a second benzene series chromatographic column and a second total hydrocarbon chromatographic column, wherein the second methane chromatographic column is respectively connected to port 1 of the six-way valve and port 9 of the fourteen-way valve, the second benzene series chromatographic column is respectively connected to port 3 of the six-way valve and port 5 of the fourteen-way valve, and the second total hydrocarbon chromatographic column is connected to port 2 of the six-way valve and port 13 of the fourteen-way valve.

[0013] Further, the multiple quantitative rings include: a third quantitative ring, a fourth quantitative ring and a fifth quantitative ring, wherein the third quantitative ring is respectively connected to port No. 2 of the fourteen-way valve and port No. 13 of the fourteen-way valve, the fourth quantitative ring is respectively connected to port No. 7 of the fourteen-way valve and port No. 10 of the fourteen-way valve, and the fifth quantitative ring is respectively connected to port No. 3 of the fourteen-way valve and port No. 6 of the fourteen-way valve.

[0014] Furthermore, the carrier gas includes: a fourth carrier gas, a fifth carrier gas and a sixth carrier gas; port No. 1 of the fourteen-way valve is used to connect the sample gas; port No. 2 of the fourteen-way valve is used to discharge the sample gas after completing the quantification; port No. 6 of the six-way valve is used to connect the fifth carrier gas; port No. 12 of the fourteen-way valve is used to connect the fourth carrier gas; port No. 4 of the fourteen-way valve is used to connect the sixth carrier gas.

[0015] Furthermore, port No. 4 of the six-way valve is used to discharge methane in the benzene series chromatographic column when the methane chromatographic column is used to detect methane, and is used to discharge high-boiling point compounds in the methane chromatographic column when the benzene series chromatographic column is used to detect benzene series.

[0016] In an embodiment of the present invention, a fourteen-way valve is used to connect sample gas and carrier gas, and the quantitative sample gas is sent to multiple chromatographic columns through a quantitative loop and a carrier gas, and after the quantification is completed, the quantitative sample gas is discharged; multiple quantitative loops are used to store the quantitative sample gas; multiple chromatographic columns are used to separate non-methane total hydrocarbons and / or benzene series in the quantitative sample gas, and the separated quantitative sample gas is sent to an FID detector; the FID detector is used to detect the separated quantitative sample gas to determine the content of non-methane total hydrocarbons and the content of benzene series in the sample gas. The present application achieves the purpose of continuous monitoring of non-methane total hydrocarbons and benzene series through a structure of a fourteen-way valve, multiple chromatographic columns and a single detector, thereby solving the technical problem of complex structure and high cost of the existing detection system, thereby achieving the technical effect of simplifying the structure of the detection system and reducing the cost of the detection system.

[0017] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram of a first non-methane total hydrocarbon and benzene series detection system provided in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the sampling state of the first non-methane total hydrocarbons and benzene series detection system provided in an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of the sampling state of the first non-methane total hydrocarbon and benzene series detection system provided in an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of a second non-methane total hydrocarbon and benzene series detection system provided in an embodiment of the present invention;

[0024] Figure 5 A schematic diagram of the sampling state of the second non-methane total hydrocarbons and benzene series detection system provided in an embodiment of the present invention;

[0025] Figure 6 A schematic diagram of a first sampling state of a second non-methane total hydrocarbon and benzene series detection system provided by an embodiment of the present invention;

[0026] Figure 7 A schematic diagram of a second sampling state of a second non-methane total hydrocarbon and benzene series detection system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Embodiment 1:

[0029] Figure 1 is a schematic diagram of a detection system for non-methane total hydrocarbons and benzene derivatives according to an embodiment of the present invention, such as Figure 1 As shown, the device comprises: a fourteen-way valve 10, a plurality of chromatographic columns 30, a plurality of quantitative loops 20 and a FID detector 40, wherein the fourteen-way valve is respectively connected to the plurality of chromatographic columns and the plurality of quantitative loops, and the plurality of chromatographic columns is connected to the FID detector;

[0030] The fourteen-way valve 10 is used to connect the sample gas and the carrier gas, and to deliver the quantitative sample gas into the multiple chromatographic columns through the quantitative loop and the carrier gas, and to discharge the quantitative sample gas after the quantitative determination is completed;

[0031] It should be noted that the above-mentioned carrier gas includes: a first carrier gas, a second carrier gas and a third carrier gas. Port 1 of the fourteen-way valve is used to connect the sample gas, port 2 of the fourteen-way valve is used to discharge the sample gas after completing the quantification, port 4 of the fourteen-way valve is used to connect the second carrier gas, port 8 of the fourteen-way valve is used to connect the first carrier gas, and port 12 of the fourteen-way valve is used to connect the third carrier gas.

[0032] The plurality of quantitative rings 20 are used to store the quantitative sample gas;

[0033] It should be noted that if Figure 2 and Figure 3 As shown, the above-mentioned multiple quantitative rings include: a first quantitative ring 1 and a second quantitative ring 2, wherein the first quantitative ring is respectively connected to ports 7 and 14 of the fourteen-way valve, and the second quantitative ring is respectively connected to ports 3 and 6 of the fourteen-way valve.

[0034] The plurality of chromatographic columns 30 are used to separate non-methane total hydrocarbons and / or benzene series in the quantitative sample gas, and to send the separated quantitative sample gas to the FID detector;

[0035] It should be noted that if Figure 2 and Figure 3 As shown, the above-mentioned multiple chromatographic columns include: a first methane chromatographic column 31, a first benzene series chromatographic column 32, a first total hydrocarbon chromatographic column 33 and a pre-column 34, wherein the first methane chromatographic column is respectively connected to port 9 of the fourteen-way valve and the FID detector, the first benzene series chromatographic column is respectively connected to port 11 of the fourteen-way valve and the first total hydrocarbon chromatographic column, the first total hydrocarbon chromatographic column is connected to port 5 of the fourteen-way valve, and the pre-column is respectively connected to port 10 of the fourteen-way valve and port 13 of the fourteen-way valve.

[0036] The FID detector 40 is used to complete the detection of the separated quantitative sample gas and determine the content of non-methane total hydrocarbons and the content of benzene series in the sample gas.

[0037] In an embodiment of the present invention, a fourteen-way valve is used to connect sample gas and carrier gas, and the quantitative sample gas is sent to multiple chromatographic columns through a quantitative loop and a carrier gas, and after the quantification is completed, the quantitative sample gas is discharged; multiple quantitative loops are used to store the quantitative sample gas; multiple chromatographic columns are used to separate non-methane total hydrocarbons and / or benzene series in the quantitative sample gas, and the separated quantitative sample gas is sent to an FID detector; the FID detector is used to detect the separated quantitative sample gas to determine the content of non-methane total hydrocarbons and the content of benzene series in the sample gas. The present application achieves the purpose of continuous monitoring of non-methane total hydrocarbons and benzene series through a structure of a fourteen-way valve, multiple chromatographic columns and a single detector, thereby solving the technical problem of complex structure and high cost of the existing detection system, thereby achieving the technical effect of simplifying the structure of the detection system and reducing the cost of the detection system.

[0038] The following will be combined Figure 2 and Figure 3 The working process of the above-mentioned non-methane total hydrocarbons and benzene series detection system is explained.

[0039] Figure 2 This is the sampling state of the detection system, that is, the benzene separation state: the sample gas enters through port 1 of the 14-way valve, flows through ports 14 and 7 to enter the first quantitative loop, and then the quantitative sample gas enters port 6, fills the second quantitative loop between ports 6 and 3, and then is discharged from port 2.

[0040] During this process, the sample gas fills two quantitative loops. The first carrier gas enters the 14-way valve from port 8, and the first methane chromatographic column component is swept into the detector through port 9.

[0041] The second carrier gas flows through ports 4 and 5 of the 14-way valve to purge the components in the first total hydrocarbon chromatographic column into the detector.

[0042] The third carrier gas flows through ports 12 and 13 of the fourteen-way valve, and sweeps the components separated in the pre-column into the first benzene series chromatographic column through ports 10 and 11 of the fourteen-way valve, where they are separated and enter the detector in sequence.

[0043] Figure 3 To detect the injection measurement status of the system, the 14-way valve is switched as follows: Figure 3 In the state shown, at this time: the sample gas is exhausted after passing through ports 1 and 2 of the 14-way valve.

[0044] In the injection measurement state, the second carrier gas enters the No. 3 port from the No. 4 port, and the quantitative sample gas in the second quantitative loop is blown into the first total hydrocarbon chromatographic column through the No. 6 port and the No. 5 port.

[0045] Because the first total hydrocarbon chromatographic column does not separate the sample gas, the sample gas first flows out of the total hydrocarbon chromatographic column and enters the detector for the analysis step.

[0046] In addition, in the injection measurement state, the first carrier gas flows through ports 8 and 7, and the sample gas in the first quantitative loop is blown into the pre-column through ports 14 and 13. When the sample gas flows through the pre-column, the low-boiling point and high-boiling point components are separated, and the low-boiling point component enters the first methane chromatographic column through ports 10 and 9 with the first carrier gas, and methane is separated first and sent to the detector. At this time, the high-boiling point component has not passed through the pre-column, and the low-boiling point volatile organic component, except methane, also remains in the first methane chromatographic column.

[0047] In addition, in the injection measurement state, the third carrier gas flows through port No. 12 and port No. 11 to purge the first benzene series chromatographic column.

[0048] When the total hydrocarbons and methane components are ionized and analyzed by the detector, the 14-way valve is switched to the sampling state. At this time, the third carrier gas will pass through ports 12 and 13 to sweep the high-boiling point components separated in the pre-column into the first benzene series chromatographic column, and after the separation of the benzene series is completed, they will enter the detector in turn for ionization.

[0049] After the analysis of benzene series is completed, the fourteen-way valve is switched to the injection state, and the continuous monitoring of non-methane total hydrocarbons and benzene series in the sample gas is achieved by the cycle of the sampling state and the injection state.

[0050] The present application realizes continuous monitoring of non-methane total hydrocarbons and benzene series through a fourteen-way valve, a detector, two quantitative loops and four chromatographic columns, reduces the use of system components, optimizes the principle of the continuous monitoring system, and reduces the technical complexity of the continuous monitoring system.

[0051] The continuous detection system in this application has a simple structure, is convenient for daily maintenance and troubleshooting, and has advantages in online continuous monitoring of volatile organic compound emission concentrations.

[0052] When the detection system continuously monitors, the volume and mass of the sample gas collected by the quantitative loop during each sampling process are consistent. At the same time, the flow rate of each carrier gas remains constant, the damping of each chromatographic column remains unchanged, the separation efficiency and volume ratio of the sample gas in each chromatographic column are constant during each injection, and the response time of the detector remains stable. Therefore, the continuous monitoring system can perform accurate qualitative and quantitative analysis on each sample collected.

[0053] In an embodiment of the present invention, a second non-methane total hydrocarbon and benzene series detection system is also provided, such as Figure 4-Figure 7 As shown, in addition to a 14-port valve, multiple chromatographic columns, multiple quantitative loops and an FID detector, the system also includes:

[0054] The six-way valve 50 is respectively connected to the fourteen-way valve, the multiple chromatographic columns and the FID detector, and the multiple chromatographic columns are connected to the FID detector.

[0055] It should be noted that port No. 5 of the six-way valve is connected to port No. 8 of the fourteen-way valve, port No. 2 of the six-way valve is connected to the FID detector, and port No. 4 of the six-way valve is used to discharge methane in the benzene series chromatographic column when the methane chromatographic column is used to detect methane, and is used to discharge high-boiling point compounds in the methane chromatographic column when the benzene series chromatographic column is used to detect benzene series.

[0056] In the embodiment of the present invention, Figure 4-Figure 7 As shown, the multiple chromatographic columns in the second non-methane total hydrocarbon and benzene series detection system include: a second methane chromatographic column 35, a second benzene series chromatographic column 36 and a second total hydrocarbon chromatographic column 37, wherein the second methane chromatographic column is respectively connected to port 1 of the six-way valve and port 9 of the fourteen-way valve, the second benzene series chromatographic column is respectively connected to port 3 of the six-way valve and port 5 of the fourteen-way valve, and the second total hydrocarbon chromatographic column is connected to port 2 of the six-way valve and port 13 of the fourteen-way valve.

[0057] The multiple quantitative rings in the second non-methane total hydrocarbon and benzene series detection system include: a third quantitative ring 3, a fourth quantitative ring 4 and a fifth fourth quantitative ring 5, wherein the third quantitative ring is respectively connected to port No. 2 of the fourteen-way valve and port No. 13 of the fourteen-way valve, the fourth quantitative ring is respectively connected to port No. 7 of the fourteen-way valve and port No. 10 of the fourteen-way valve, and the fifth quantitative ring is respectively connected to port No. 3 of the fourteen-way valve and port No. 6 of the fourteen-way valve.

[0058] The carrier gas in the second non-methane total hydrocarbon and benzene series detection system includes: a fourth carrier gas, a fifth carrier gas and a sixth carrier gas. Port 1 of the fourteen-way valve is used to connect the sample gas, port 2 of the fourteen-way valve is used to discharge the quantitative sample gas after the quantification is completed, port 6 of the six-way valve is used to connect the fifth carrier gas, port 12 of the fourteen-way valve is used to connect the fourth carrier gas, and port 4 of the fourteen-way valve is used to connect the sixth carrier gas.

[0059] The following will be combined Figure 4-Figure 7 The working process of the second non-methane total hydrocarbons and benzene series detection system is explained.

[0060] The second non-methane total hydrocarbon and benzene series detection system includes: an FID detector, a fourteen-way valve (the fourteen-way valve is divided into two states, AB, 1-14 ports in state A, 1-2 ports in state B), a six-way valve (the six-way valve is divided into two states, AB, 1-6 ports in state A, 1-2 ports in state B), three quantitative loops, a second total hydrocarbon chromatographic column, a second methane chromatographic column, a second benzene series chromatographic column, and a three-way connector.

[0061] The second type of non-methane total hydrocarbons and benzene series includes two states, namely sampling state and injection state:

[0062] Sampling state: Sampling state is quantitative state, 14-way valve is state A, 6-way valve is state B, such as Figure 5 shown.

[0063] Sample gas path: The sample gas can be drawn into the sample gas inlet under negative pressure through the sampling pump and discharged from the sample gas outlet. The sample gas passes through the sample gas inlet, port 1 of the fourteen-way valve, port 14 of the fourteen-way valve, the third quantitative loop, port 11 of the fourteen-way valve, port 10 of the fourteen-way valve, the fourth quantitative loop, port 7 of the fourteen-way valve, port 6 of the fourteen-way valve, the fifth quantitative loop, port 3 of the fourteen-way valve, port 2 of the fourteen-way valve, and the sample gas is emptied. In this state, the sample gas can fill the third quantitative loop, the fourth quantitative loop, and the fifth quantitative loop. When the quantitative calculation of the three quantitative loops is completed, the quantitative sample gas is purged to the chromatographic column and the FID detector to prepare for quantitative calculation.

[0064] Gas path of the fourth carrier gas: The fourth carrier gas passes through port 12 of the fourteen-way valve, port 13 of the fourteen-way valve, a three-way joint, and an FID detector. In this state, the fourth carrier gas purges the total hydrocarbon column in a positive direction, thereby cleaning the total hydrocarbon column.

[0065] Gas path of the fifth carrier gas: The fifth carrier gas passes through port 6 of the six-way valve, port 1 of the six-way valve, port 8 of the fourteen-way valve, the second methane chromatographic column, port 9 of the fourteen-way valve, port 8 of the fourteen-way valve, port 5 of the six-way valve, port 4 of the six-way valve, and is emptied. In this state, the fifth carrier gas is activated to reversely purge the second methane chromatographic column. Back-flushing the second methane chromatographic column can empty the high-boiling point compounds remaining from the previous measurement, extend the service life of the second methane chromatographic column, and improve the accuracy of the measurement data.

[0066] Gas path of the sixth carrier gas: The sixth carrier gas passes through port 4 of the fourteen-way valve, port 5 of the fourteen-way valve, the second benzene series chromatographic column, port 3 of the six-way valve, port 2 of the six-way valve, a three-way joint, and an FID detector. In this state, the sixth carrier gas purges the benzene series column in a forward direction, playing the role of forward cleaning the benzene series column.

[0067] The second injection state of non-methane total hydrocarbons and benzene series is the injection analysis state, and the injection state is divided into a first injection state and a second injection state.

[0068] like Figure 6 As shown, Figure 6 It is a schematic diagram of the first injection state of the second non-methane total hydrocarbons and benzene series. In this state, the fourteen-way valve is converted from state A to state B, and the six-way valve is converted from state A to state B.

[0069] Gas path of the fourth carrier gas: The fourth carrier gas passes through port 12 of the fourteen-way valve, port 11 of the fourteen-way valve, the third quantitative loop, port 14 of the fourteen-way valve, port 13 of the fourteen-way valve, the second total hydrocarbon chromatographic column, the three-way joint, and the FID detector. In this state, the sample gas in the third quantitative loop can be forward purged through the total hydrocarbon column to the FID detector to detect the total hydrocarbon content in the sample gas.

[0070] Gas path of the fifth carrier gas: The fifth carrier gas passes through port 6 of the six-way valve, port 5 of the six-way valve, port 8 of the fourteen-way valve, port 7 of the fourteen-way valve, the fourth quantitative loop, port 10 of the fourteen-way valve, port 9 of the fourteen-way valve, the second methane chromatographic column, port 1 of the six-way valve, port 2 of the six-way valve, a three-way joint, and an FID detector. In this state, the methane content in the sample gas can be detected by forward purging the sample gas in the fourth quantitative loop through the second methane chromatographic column to the FID detector.

[0071] Gas path of the sixth carrier gas: The sixth carrier gas is exhausted through port 4 of the fourteen-way valve, port 4 of the fourteen-way valve, port 3 of the fourteen-way valve, the fifth quantitative loop, port 6 of the fourteen-way valve, port 5 of the fourteen-way valve, the second benzene series chromatographic column, port 3 of the six-way valve, port 4 of the six-way valve. In this state, the sample gas in the fifth quantitative loop can be purged forward through the methane in the second benzene series chromatographic column by the carrier gas to avoid interference between the methane in the second benzene series chromatographic column and the methane in the second methane chromatographic column.

[0072] like Figure 7 As shown, Figure 7 This is the second injection state for the second non-methane total hydrocarbons and benzene series: after the methane in the second methane chromatographic column completes the response on the FID detector, the six-way valve is converted from state B to state A. In this state, the second methane chromatographic column is emptied in a forward direction, and other components remaining in the second methane chromatographic column are purged and emptied in a forward direction to avoid interference in the detection of benzene series.

[0073] The fourth carrier gas path: the fourth carrier gas passes through port No. 12 of the fourteen-way valve, port No. 11 of the fourteen-way valve, port No. 14 of the fourteen-way valve, port No. 13 of the fourteen-way valve, the second total hydrocarbon chromatographic column, the three-way joint, and FID detection.

[0074] The fifth carrier gas path: The fifth carrier gas is emptied through the six-way valve port 6, six-way valve port 1, fourteen-way valve port 9, fourteen-way valve port 10, fourteen-way valve port 7, fourteen-way valve port 8, six-way valve port 5, six-way valve port 4. In this state, the compounds with peak time after methane are purged and emptied in a forward direction to avoid interference with the benzene series in the second benzene series chromatographic column.

[0075] Gas path of the sixth carrier gas: the carrier gas passes through port 4 of the fourteen-way valve, port 3 of the fourteen-way valve, port 6 of the fourteen-way valve, port 5 of the fourteen-way valve, port 3 of the six-way valve, port 2 of the six-way valve, a three-way joint, and FID detection. In this state, the benzene series in the second benzene series chromatographic column can be forward purged to the FID detector for analysis by the carrier gas.

[0076] The embodiment of the present invention proposes a detection system for non-methane total hydrocarbons and benzene series, which adopts a single detector, three chromatographic columns, and three quantitative ring structures. Total hydrocarbons, methane, and benzene series are quantified using their own quantitative rings, and the data is accurate. The sampling and analysis process is realized by switching two multi-way valves, a 14-way valve and a 6-way valve, thereby solving the problems of different responsivity of the dual detectors and low responsivity of backflushing measurement of benzene series in the previous scheme.

[0077] In the embodiment of the present invention, the second non-methane total hydrocarbon and benzene series detection system uses two multi-way injection valves to switch different states to realize the sample collection and analysis process, shortening the analysis cycle. The analysis results are highly reliable and the data is accurate, avoiding the uncertainty of different responsivities of the dual detectors.

[0078] The second non-methane total hydrocarbon and benzene series detection system has high sensitivity and can accurately test low-concentration benzene series data, effectively avoiding the problem of low benzene series response caused by backflushing benzene series through the methane analysis column.

[0079] The second type of non-methane total hydrocarbon and benzene series detection system has a compact and reliable internal structure, and the carrier gas passes through each state of the chromatographic column to avoid oxidation and deactivation of the internal filler. Back-flushing the methane analysis column during the sampling process can reversely evacuate the high-boiling point compounds remaining in the methane analysis column, which can effectively improve the separation efficiency of the chromatographic group, improve the analysis accuracy, and extend the service life of the chromatographic column.

[0080] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0081] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0082] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0083] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0084] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0085] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A detection system for non-methane total hydrocarbons and benzene series, characterized in that: include: A fourteen-way valve, a plurality of chromatographic columns, a plurality of quantitative loops and a FID detector, wherein the fourteen-way valve is respectively connected to the plurality of chromatographic columns and the plurality of quantitative loops, and the plurality of chromatographic columns is connected to the FID detector; The fourteen-way valve is used to connect the sample gas and the carrier gas, and to deliver the quantitative sample gas into the multiple chromatographic columns through the quantitative loop and the carrier gas, and to discharge the quantitative sample gas after the quantitative determination is completed; The multiple quantitative rings are used to store the quantitative sample gas; the multiple quantitative rings include: a first quantitative ring and a second quantitative ring, wherein the first quantitative ring is respectively connected to the No. 7 port and the No. 14 port of the fourteen-way valve, and the second quantitative ring is respectively connected to the No. 3 port and the No. 6 port of the fourteen-way valve; The multiple chromatographic columns are used to separate the non-methane total hydrocarbons and / or benzene series in the quantitative sample gas, and to send the separated quantitative sample gas to the FID detector; the multiple chromatographic columns include: a first methane chromatographic column, a first benzene series chromatographic column, a first total hydrocarbon chromatographic column and a pre-column, wherein the first methane chromatographic column is respectively connected to port No. 9 of the fourteen-way valve and the FID detector, the first benzene series chromatographic column is respectively connected to port No. 11 of the fourteen-way valve and the first total hydrocarbon chromatographic column, the first total hydrocarbon chromatographic column is connected to port No. 5 of the fourteen-way valve, and the pre-column is respectively connected to port No. 10 of the fourteen-way valve and port No. 13 of the fourteen-way valve; The carrier gas includes: a first carrier gas, a second carrier gas and a third carrier gas; Port No. 1 of the 14-way valve is used to connect the sample gas; Port No. 2 of the 14-way valve is used to discharge the sample gas after the quantitative determination is completed; Port No. 4 of the 14-way valve is used to connect the second carrier gas; Port No. 8 of the 14-way valve is used to connect the first carrier gas; Port No. 12 of the 14-way valve is used to connect the third carrier gas; The FID detector is used to complete the detection of the separated quantitative sample gas to determine the content of non-methane total hydrocarbons and the content of benzene series in the sample gas; The system further comprises: a six-way valve, wherein the six-way valve is respectively connected to the fourteen-way valve, the multiple chromatographic columns and the FID detector, and the multiple chromatographic columns are connected to the FID detector.

2. The system according to claim 1, characterized in that Port No. 5 of the six-way valve is connected to port No. 8 of the fourteen-way valve; Port No. 2 of the six-way valve is connected to the FID detector.

3. The system according to claim 2, characterized in that The multiple chromatographic columns include: a second methane chromatographic column, a second benzene series chromatographic column and a second total hydrocarbon chromatographic column, wherein the second methane chromatographic column is respectively connected to port 1 of the six-way valve and port 9 of the fourteen-way valve, the second benzene series chromatographic column is respectively connected to port 3 of the six-way valve and port 5 of the fourteen-way valve, and the second total hydrocarbon chromatographic column is connected to port 2 of the six-way valve and port 13 of the fourteen-way valve.

4. The system according to claim 2, characterized in that The multiple quantitative rings include: a third quantitative ring, a fourth quantitative ring and a fifth quantitative ring, wherein the third quantitative ring is respectively connected to port No. 2 of the fourteen-way valve and port No. 13 of the fourteen-way valve, the fourth quantitative ring is respectively connected to port No. 7 of the fourteen-way valve and port No. 10 of the fourteen-way valve, and the fifth quantitative ring is respectively connected to port No. 3 of the fourteen-way valve and port No. 6 of the fourteen-way valve.

5. The system according to claim 1, characterized in that The carrier gas includes: a fourth carrier gas, a fifth carrier gas and a sixth carrier gas; Port No. 1 of the 14-way valve is used to connect the sample gas; Port No. 2 of the 14-way valve is used to discharge the sample gas after the quantitative determination is completed; Port No. 6 of the six-way valve is used to connect the fifth carrier gas; Port No. 12 of the 14-way valve is used to connect the fourth carrier gas; Port No. 4 of the fourteen-way valve is used to connect the sixth carrier gas.

6. The system according to claim 3, characterized in that Port No. 4 of the six-way valve is used to discharge methane in the benzene series chromatographic column when the second methane chromatographic column is performing methane detection, and is used to discharge high-boiling point compounds in the methane chromatographic column when the benzene series chromatographic column is detecting benzene series.

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