An analysis device, analysis method and application for natural gas product quality indicators

Abstract

The present invention provides a natural gas product quality index analysis device, an analysis method and an application. The device includes a sample injection assembly and first, second, third, fourth, and fifth chromatographic column analysis systems connected in parallel; the first chromatographic column analysis system is used to separate sulfides in natural gas; the second chromatographic column analysis system is used to separate hydrocarbons with more than C3 in natural gas; the third chromatographic column analysis system is used to separate oxygen, nitrogen, methane and carbon monoxide in natural gas; the fourth chromatographic column analysis system is used to separate carbon dioxide and ethane in natural gas; the fifth chromatographic column analysis system is used to separate helium and hydrogen in natural gas; each chromatographic column analysis system is provided with a quantitative tube, a carrier gas tube and a chromatographic column; the sample injection assembly is communicatively connected to the quantitative tubes of each chromatographic column analysis system in a controllable manner, and is used to provide natural gas sample gas to the quantitative tubes of each chromatographic column analysis system; each chromatographic column analysis system is respectively connected to a corresponding detector.

Description

Technical Field

[0001] The present invention belongs to the technical field of natural gas detection, and particularly relates to an analysis device, an analysis method and an application for analyzing the quality indexes of natural gas products. Background Art

[0002] According to the provisions of the mandatory national standard GB 17820-2018 "Natural Gas", after the natural gas produced from gas fields or oil fields is pretreated, the commercial natural gas transported through pipelines has requirements for four quality indexes: gross calorific value, total sulfur content (calculated as sulfur), hydrogen sulfide content, and carbon dioxide content.

[0003] The common conventional detection methods for the quality indexes of natural gas products usually include the following: The gross calorific value is usually obtained by calculating from the composition data after detecting the composition by chromatography. The total sulfur content is usually detected by coulometry, ultraviolet fluorescence method or hydrogenolysis rate colorimetry. The hydrogen sulfide content is usually detected by iodometry, methylene blue method, laser method, chromatography or colorimetry. The carbon dioxide mole fraction is usually detected by chromatography. It can be seen that there are many principles for the detection methods of natural gas quality control indexes, and often multiple instruments and multiple sample injections are required for analysis to complete the detection, resulting in a long detection cycle. At the same time, due to the need for multiple sample injections, it is difficult to ensure the consistency of samples. The above problems are technical problems that urgently need to be solved in this field. Summary of the Invention

[0004] The purpose of the present invention is to provide an analysis device and an analysis method that are convenient for obtaining the quality indexes of natural gas products.

[0005] To achieve the above purpose, the present invention provides an analysis device for the quality indexes of natural gas products. Among them, the device includes a sample injection assembly and a first chromatographic column analysis system, a second chromatographic column analysis system, a third chromatographic column analysis system, a fourth chromatographic column analysis system, and a fifth chromatographic column analysis system connected in parallel. The first chromatographic column analysis system is used to separate sulfides in natural gas. The second chromatographic column analysis system is used to separate hydrocarbons with more than C3 in natural gas. The third chromatographic column analysis system is used to separate oxygen, nitrogen, methane and carbon monoxide in natural gas. The fourth chromatographic column analysis system is used to separate carbon dioxide and ethane in natural gas. The fifth chromatographic column analysis system is used to separate helium and hydrogen in natural gas. Among them,

[0006] Each chromatographic column analysis system is provided with a quantitative tube, a carrier gas pipe and a chromatographic column. The quantitative tube is used to store the natural gas sample gas, and the carrier gas pipe is used to transport the carrier gas to the chromatographic column analysis system to drive the natural gas sample gas in the quantitative tube to perform component separation in the chromatographic column.

[0007] The sampling component is controllably connected to the quantitative tubes of the first chromatographic column analysis system, the second chromatographic column analysis system, the third chromatographic column analysis system, the fourth chromatographic column analysis system, and the fifth chromatographic column analysis system, and is used to provide natural gas sample gas to the quantitative tubes of the first chromatographic column analysis system, the second chromatographic column analysis system, the third chromatographic column analysis system, the fourth chromatographic column analysis system, and the fifth chromatographic column analysis system;

[0008] Each chromatographic column analysis system is respectively connected to a corresponding detector.

[0009] Each chromatographic column analysis system being respectively connected to a corresponding detector can realize the content analysis of each component separated by each chromatographic column analysis system. The first chromatographic column analysis system being connected to a corresponding detector is used to realize the content analysis of sulfides in natural gas; the second chromatographic column analysis system being connected to a corresponding detector is used to realize the content analysis of hydrocarbons above C3 in natural gas; the third chromatographic column analysis system being connected to a corresponding detector is used to realize the content analysis of oxygen, nitrogen, methane, and carbon monoxide in natural gas; the fourth chromatographic column analysis system being connected to a corresponding detector is used to realize the content analysis of carbon dioxide and ethane in natural gas; the fifth chromatographic column analysis system being connected to a corresponding detector is used to realize the content analysis of helium and hydrogen in natural gas.

[0010] The natural gas product quality index analysis equipment provided by the present invention divides the natural gas components into five parts for component separation respectively. In each part of component separation, each target analyte is separated by a chromatographic column, and then the content of each target analyte in this part is obtained by using a corresponding detector, having the following beneficial effects:

[0011] On the one hand, based on the analysis results of these five parts, it is very convenient to determine the natural gas product quality indexes, including the gross calorific value, total sulfur content (calculated as sulfur, mg / m 3 ), hydrogen sulfide content (mg / m 3 ), and carbon dioxide content (mole percentage);

[0012] On the other hand, it helps to achieve a higher peak resolution of the target analyte in the chromatogram obtained by using a corresponding detector, with more accurate results, and can better ensure the accuracy of obtaining the natural gas product quality indexes;

[0013] On yet another hand, the natural gas product quality index analysis equipment provided by the present invention is an integrated equipment. The sampling component is used to inject samples into each system, and then each analysis system is respectively used to analyze various components, with convenient operation, which helps to shorten the detection cycle.

[0014] In the above natural gas product quality index analysis device, preferably, the first chromatographic column analysis system is used to separate carbonyl sulfide, hydrogen sulfide, methanethiol, ethanethiol, methyl sulfide, methyl ethyl sulfide, dimethyl disulfide, ethyl sulfide, carbon disulfide, n-butyl mercaptan, tert-butyl mercaptan, isopropyl mercaptan, and thiophene in natural gas.

[0015] In the above natural gas product quality index analysis device, preferably, the sampling assembly is communicated with the metering tubes of the first chromatographic column analysis system, the second chromatographic column analysis system, the third chromatographic column analysis system, the fourth chromatographic column analysis system, and the fifth chromatographic column analysis system, so as to realize the series connection of the metering tubes of the first chromatographic column analysis system, the second chromatographic column analysis system, the third chromatographic column analysis system, the fourth chromatographic column analysis system, and the fifth chromatographic column analysis system; wherein, the sampling assembly includes a natural gas inlet pipe, a natural gas outlet pipe, and a first metering tube connecting pipe, a second metering tube connecting pipe, a third metering tube connecting pipe, and a fourth metering tube connecting pipe. The first metering tube connecting pipe, the second metering tube connecting pipe, the third metering tube connecting pipe, and the fourth metering tube connecting pipe are respectively used to connect the metering tubes in series. The natural gas inlet pipe is communicated with the inlet end of the series-connected metering tubes, and the natural gas outlet pipe is communicated with the outlet end of the series-connected metering tubes;

[0016] In this preferred embodiment, the series connection method is more helpful for performing a single injection on each analysis system, and can better ensure the consistency of the samples; in addition, through a single injection, various components can be analyzed by each system respectively, which helps to further shorten the detection cycle;

[0017] In a specific embodiment, the natural gas inlet pipe is communicated with the inlet end of the metering tube of the first chromatographic column analysis system. The first metering tube connecting pipe is respectively communicated with the outlet end of the metering tube of the first chromatographic column analysis system and the inlet end of the metering tube of the second chromatographic column analysis system. The second metering tube connecting pipe is respectively communicated with the outlet end of the metering tube of the second chromatographic column analysis system and the inlet end of the metering tube of the third chromatographic column analysis system. The third metering tube connecting pipe is respectively communicated with the outlet end of the metering tube of the third chromatographic column analysis system and the inlet end of the metering tube of the fourth chromatographic column analysis system. The fourth metering tube connecting pipe is respectively communicated with the outlet end of the metering tube of the fourth chromatographic column analysis system and the inlet end of the metering tube of the fifth chromatographic column analysis system. The natural gas outlet pipe is communicated with the outlet end of the metering tube of the fifth chromatographic column analysis system.

[0018] In the above natural gas product quality index analysis equipment, preferably, the first chromatographic column analysis system is connected to a sulfur chemiluminescence detector (SCD detector), the second chromatographic column analysis system is connected to a flame ionization detector (FID detector), the third chromatographic column analysis system is connected to a thermal conductivity detector (TCD detector), the fourth chromatographic column analysis system is connected to a thermal conductivity detector (TCD detector), and / or the fifth chromatographic column analysis system is connected to a thermal conductivity detector (TCD detector);

[0019] More preferably, the natural gas product quality index analysis equipment further includes a sulfur chemiluminescence detector, and the sulfur chemiluminescence detector is connected to the first chromatographic column analysis system;

[0020] More preferably, the natural gas product quality index analysis equipment further includes a flame ionization detector, and the flame ionization detector is connected to the second chromatographic column analysis system.

[0021] More preferably, the natural gas product quality index analysis equipment further includes a first thermal conductivity detector, and the first thermal conductivity detector is respectively connected to the third chromatographic column analysis system and the fourth chromatographic column analysis system.

[0022] More preferably, the natural gas product quality index analysis equipment further includes a second thermal conductivity detector, and the second thermal conductivity detector is connected to the fifth chromatographic column analysis system.

[0023] In the above natural gas product quality index analysis equipment, preferably, the chromatographic column of the first chromatographic column analysis system includes a sulfur column; in the first chromatographic column analysis system, one end of the quantitative tube is connected to the carrier gas pipe through a controllable on-off connection pipeline, and the other end is connected to the inlet end of the sulfur column through a controllable on-off connection pipeline, and the outlet end of the sulfur column is connected to the sulfur chemiluminescence detector through a controllable on-off connection pipeline;

[0024] Among them, the sulfur column can separate carbonyl sulfide, hydrogen sulfide, methanethiol, ethanethiol, methyl sulfide, methyl ethyl sulfide, dimethyl disulfide, ethyl sulfide, carbon disulfide, n-butyl mercaptan, tert-butyl mercaptan, isopropyl mercaptan, and thiophene;

[0025] More preferably, the sulfur column is selected from one of methyl silicone type chromatographic columns, phthalate type chromatographic columns, bonded silica PLOT type chromatographic columns, high permeability PLOT type chromatographic columns, and optimized non-polar stationary phase type chromatographic columns;

[0026] Further preferably, the sulfur column is selected from a GS-GasPro chromatographic column (belonging to the bonded silica PLOT type chromatographic column) and a DB-Sulfur SCD chromatographic column (belonging to the optimized non-polar stationary phase type chromatographic column);

[0027] More preferably, the sulfur column is a DB-Sulfur SCD chromatographic column; wherein, the length of the DB-Sulfur SCD chromatographic column is 50m - 60m. In a specific embodiment, the dimensions of the DB-Sulfur SCD chromatographic column are 60m in length, 0.32mm in diameter, and 4.2μm in liquid film thickness;

[0028] The DB-Sulfur SCD chromatographic column has more superior performance compared to other types of chromatographic columns and can achieve a complete analysis of sulfides within an appropriate time. Although the GS-GasPro chromatographic column can completely analyze sulfides, a complete analysis takes about 45 minutes, which does not meet the production requirements. For methyl silicone-based chromatographic columns, phthalate-based chromatographic columns, and bonded silica PLOT chromatographic columns, the analysis of sulfur compounds is incomplete, and there is even a tailing phenomenon.

[0029] In the above natural gas product quality index analysis equipment, preferably, the chromatographic column of the second chromatographic column analysis system includes a first pre-separation column and a first chromatographic analysis column; in the second chromatographic column analysis system, one end of the quantitative tube is connected to the carrier gas pipe through a controllable on-off connection pipeline, and the other end is connected to the inlet end of the first pre-separation column through a controllable on-off connection pipeline. The outlet end of the first pre-separation column is connected to the inlet end of the first chromatographic analysis column through a controllable on-off connection pipeline. The carrier gas pipe is respectively connected to the outlet end of the first pre-separation column and the inlet end of the first chromatographic analysis column through controllable on-off connection pipelines. The inlet end of the first pre-separation column and the outlet end of the first chromatographic analysis column are respectively connected to the hydrogen flame detector through controllable on-off connection pipelines;

[0030] Among them, the first pre-separation column can separate hydrocarbon components of C6 + (hydrocarbon components containing 6 or more carbon atoms) from hydrocarbon components of C5 - (hydrocarbon components containing 5 or fewer carbon atoms);

[0031] The first chromatographic analysis column can separate propane, isobutane, n-butane, neopentane, isopentane, and n-pentane;

[0032] More preferably, the first pre-separation column is selected from an OV-1 pre-separation column and a DB-1 capillary column; still more preferably, the OV-1 pre-separation column is selected; still more preferably, the packing material of the OV-1 pre-separation column includes diatomaceous earth 545 with 80-100 meshes and silicone OV-1, wherein the content of silicone OV-1 is 10%-20% based on the mass of diatomaceous earth 545 (Silicone OV-1 10% Celite545 80 / 100mesh); still more preferably, the length of the OV-1 pre-separation column is 1.0-2.0 m; still more preferably, the length of the DB-1 capillary column is 3.0-5.0 m; in a specific embodiment, the size of the OV-1 pre-separation column is an outer diameter of 1.6 mm, an inner diameter of 1.0 mm and a length of 1.0 m; in a specific embodiment, the size of the DB-1 capillary column is a length of 5.0 m, a diameter of 0.55 mm and a liquid film thickness of 20 μm;

[0033] More preferably, the first chromatographic analysis column is selected from an HP-Al / S chromatographic column, an HP-PLOT Al2O3 S capillary column, a PONA capillary column and a plot Q capillary column; still more preferably, the HP-Al / S chromatographic column is selected; still more preferably, the length of the HP-Al / S chromatographic column is 30 m-50 m; still more preferably, the length of the HP-PLOT Al2O3 S capillary column is 25 m-50 m; still more preferably, the length of the PONA capillary column is 50 m-100 m; still more preferably, the length of the plot Q capillary column is 25 m-30 m; in a specific embodiment, the size of the HP-Al / S chromatographic column is a length of 50 m, a diameter of 0.53 mm and a liquid film thickness of 15 μm.

[0034] In the above natural gas product quality index analysis device, preferably, the chromatographic column of the third chromatographic column analysis system includes a second pre-separation column and a second chromatographic analysis column; in the third chromatographic column analysis system, one end of the quantitative tube is communicated with the carrier gas pipe through a controllable on-off connection pipeline, and the other end is communicated with the inlet end of the second pre-separation column through a controllable on-off connection pipeline, the outlet end of the second pre-separation column is communicated with the inlet end of the second chromatographic analysis column through a controllable on-off connection pipeline, the carrier gas pipe is respectively communicated with the outlet end of the second pre-separation column and the inlet end of the second chromatographic analysis column through controllable on-off connection pipelines, and the outlet end of the second chromatographic analysis column is communicated with a thermal conductivity detector through a controllable on-off connection pipeline;

[0035] Among them, the second pre-separation column can separate oxygen, nitrogen, methane and carbon monoxide from natural gas; the second chromatographic analysis column can separate oxygen, nitrogen, methane and carbon monoxide;

[0036] More preferably, the second pre-separation column is selected from one of Porapak N column, Porapak Q column and Porapak QS column; still more preferably, the second pre-separation column is Porapak N column; still more preferably, the mesh number of the packing material of the Porapak N column is 80-100 meshes; still more preferably, the length of the Porapak N column is 3m-5m; in a specific embodiment, the size of the Porapak N column is 1.0m in length, 3.2mm in outer diameter and 2.1mm in inner diameter;

[0037] More preferably, the second chromatographic analysis column is selected from one of 13X molecular sieve column and 5A molecular sieve column; still more preferably, the second chromatographic analysis column is MS-13X molecular sieve column; still more preferably, the length of the MS-13X molecular sieve column is 3.0m-5.0m; in a specific embodiment, the size of the MS-13X molecular sieve column is 5.0m in length, 3.2mm in outer diameter and 2.1mm in inner diameter.

[0038] In the above natural gas product quality index analysis equipment, preferably, the chromatographic column of the fourth chromatographic column analysis system includes a third pre-separation column and a third chromatographic analysis column; in the fourth chromatographic column analysis system, one end of the quantitative tube is communicated with the carrier gas pipe through a controllable on-off connecting pipeline, and the other end is communicated with the inlet end of the third pre-separation column through a controllable on-off connecting pipeline, the outlet end of the third pre-separation column is communicated with the inlet end of the third chromatographic analysis column through a controllable on-off connecting pipeline, the carrier gas pipe is respectively communicated with the outlet end of the third pre-separation column and the inlet end of the third chromatographic analysis column through a controllable on-off connecting pipeline, and the outlet end of the third chromatographic analysis column is communicated with the thermal conductivity detector through a controllable on-off connecting pipeline;

[0039] Among them, the third pre-separation column can separate ethane and CO2 from natural gas; the third chromatographic analysis column can separate ethane and CO2;

[0040] More preferably, the third pre-separation column is selected from one of Porapak N column, Porapak Q column and Porapak QS column; still more preferably, the third pre-separation column is Porapak N column; still more preferably, the mesh number of the packing material of the Porapak N column is 80-100 meshes; still more preferably, the length of the Porapak N column is 1m-2m; in a specific embodiment, the size of the Porapak N column is 1.0m in length, 3.2mm in outer diameter and 2.1mm in inner diameter;

[0041] More preferably, the third chromatographic analysis column is selected from one of Porapak N column, Porapak Q column and Porapak QS column; still more preferably, the third chromatographic analysis column is Porapak N column; still more preferably, the mesh number of the packing material of the Porapak N column is 80-100 mesh; still more preferably, the length of the Porapak N column is 2m-3m; in a specific embodiment, the size of the Porapak N column is 2.0m in length, 3.2mm in outer diameter and 2.1mm in inner diameter.

[0042] In the above natural gas product quality index analysis equipment, preferably, the chromatographic column of the fifth chromatographic column analysis system includes a fourth pre-separation column and a fourth chromatographic analysis column; in the fifth chromatographic column analysis system, one end of the quantitative tube is communicated with the carrier gas pipe through a controllable on-off connection pipeline, and the other end is communicated with the inlet end of the fourth pre-separation column through a controllable on-off connection pipeline. The outlet end of the fourth pre-separation column is communicated with the inlet end of the fourth chromatographic analysis column through a controllable on-off connection pipeline. The carrier gas pipe is respectively communicated with the outlet end of the fourth pre-separation column and the inlet end of the fourth chromatographic analysis column through a controllable on-off connection pipeline. The outlet end of the fourth chromatographic analysis column is communicated with the thermal conductivity detector through a controllable on-off connection pipeline;

[0043] Among them, the fourth pre-separation column can separate helium and hydrogen from natural gas; the fourth chromatographic analysis column can separate helium and hydrogen;

[0044] More preferably, the fourth pre-separation column is selected from one of Porapak N column, Porapak Q column and Porapak QS column; still more preferably, the fourth pre-separation column is Porapak N column; still more preferably, the mesh number of the packing material of the Porapak N column is 80-100 mesh; still more preferably, the length of the Porapak N column is 1m-2m; in a specific embodiment, the size of the Porapak N column is 1.0m in length, 3.2mm in outer diameter and 2.1mm in inner diameter;

[0045] More preferably, the fourth chromatographic analysis column is selected from one of 13X molecular sieve column and 5A molecular sieve column; still more preferably, the fourth chromatographic analysis column is MS-5A molecular sieve column; still more preferably, the mesh number of the packing material of the MS-5A molecular sieve column is 60-80 mesh; still more preferably, the length of the MS-5A molecular sieve column is 3.0m-5.0m; in a specific embodiment, the size of the MS-5A molecular sieve column is 3.0m in length, 3.2mm in outer diameter and 2.1mm in inner diameter 3.2×2.1mm×3.0m.

[0046] In the above natural gas product quality index analysis device, preferably, the first chromatographic column analysis system includes a first injection valve, and the first injection valve is a multi-way valve including a first gear and a second gear; in the first chromatographic column analysis system, the first injection valve is respectively communicated with both ends of the metering tube, communicated with the carrier gas tube, and communicated with the chromatographic column, and the on-off of the connecting pipelines between the components in the first chromatographic column analysis system and the on-off of the connecting pipelines between the injection assembly and the first chromatographic column analysis system are controlled through the first injection valve;

[0047] When the first injection valve is switched to the first gear, the gas in the injection assembly can be directly discharged from the first chromatographic column analysis system after passing through the metering tube; when the first injection valve is switched to the second gear, the gas in the carrier gas tube of the first chromatographic column analysis system can flow through the metering tube of the first chromatographic column analysis system to the chromatographic column of the first chromatographic column analysis system;

[0048] More preferably, the first injection valve is a six-way valve including a first gear and a second gear. The six-way valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, and a sixth valve port in a clockwise direction; when the six-way valve is in the first gear, the sixth valve port is communicated with the first valve port, the second valve port is communicated with the third valve port, and the fourth valve port is communicated with the fifth valve port; when the six-way valve is in the second gear, the first valve port is communicated with the second valve port, the third valve port is communicated with the fourth valve port, and the fifth valve port is communicated with the sixth valve port;

[0049] The sixth valve port and the fifth valve port of the first injection valve are respectively communicated with the injection assembly. One end of the metering tube of the first chromatographic column analysis system is communicated with the first valve port of the first injection valve, and the other end is communicated with the fourth valve port of the first injection valve. The carrier gas tube of the first chromatographic column analysis system is communicated with the second valve port of the first injection valve, and the sulfur column is communicated with the third valve port of the first injection valve.

[0050] In the above natural gas product quality index analysis device, preferably, the second chromatographic column analysis system includes a second injection valve, and the second injection valve is a multi-way valve including a first gear and a second gear; in the second chromatographic column analysis system, the second injection valve is respectively communicated with both ends of the metering tube, communicated with the carrier gas tube, and communicated with the chromatographic column, and the on-off of the connecting pipelines between the components in the second chromatographic column analysis system and the on-off of the connecting pipelines between the injection assembly and the second chromatographic column analysis system are controlled through the second injection valve;

[0051] When the second injection valve is switched to the first gear, the gas in the injection assembly can be directly discharged from the second chromatographic column analysis system after passing through the metering tube; when the second injection valve is switched to the second gear, the gas in the carrier gas tube of the second chromatographic column analysis system can flow through the metering tube of the second chromatographic column analysis system to the chromatographic column of the second chromatographic column analysis system;

[0052] More preferably, in the second chromatographic column analysis system, the second injection valve is respectively connected to both ends of the metering tube, connected to the carrier gas pipe, connected to both ends of the first pre-separation column, connected to the inlet end of the first chromatographic analysis column, and connected to the hydrogen flame detector. The on-off of the connecting pipelines between the components in the second chromatographic column analysis system and the on-off of the connecting pipelines between the injection assembly and the second chromatographic column analysis system are controlled by the second injection valve;

[0053] When the second injection valve is switched to the first gear position, it can enable the gas in the injection assembly to directly discharge from the second chromatographic column analysis system after passing through the metering tube, enable the gas in the carrier gas pipe of the second chromatographic column analysis system to enter from the outlet end of the first pre-separation column and flow out from the inlet end of the first pre-separation column and then flow into the hydrogen flame detector, and enable the gas in the carrier gas pipe of the second chromatographic column analysis system to enter the first chromatographic analysis column from the inlet end of the first chromatographic analysis column; when the second injection valve is switched to the second gear position, it can enable the gas in the carrier gas pipe of the second chromatographic column analysis system to flow through the metering tube of the second chromatographic column analysis system to the first pre-separation column, enter from the inlet end of the first pre-separation column and flow out from the outlet end of the first pre-separation column, and then enter the first chromatographic analysis column through the inlet end of the first chromatographic analysis column;

[0054] Further preferably, the second injection valve is a ten-way valve including a first gear position and a second gear position. The second injection valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port, and a tenth valve port in a clockwise direction; when the second injection valve is in the first gear position, the tenth valve port is connected to the first valve port, the second valve port is connected to the third valve port, the fourth valve port is connected to the fifth valve port, the sixth valve port is connected to the seventh valve port, and the eighth valve port is connected to the ninth valve port; when the second injection valve is in the second gear position, the first valve port is connected to the second valve port, the third valve port is connected to the fourth valve port, the fifth valve port is connected to the sixth valve port, the seventh valve port is connected to the eighth valve port, and the ninth valve port is connected to the tenth valve port;

[0055] The tenth valve port and the ninth valve port of the second injection valve are respectively connected to the injection assembly. One end of the metering tube of the second chromatographic column analysis system is connected to the first valve port of the second injection valve, and the other end is connected to the eighth valve port of the second injection valve. The carrier gas pipe of the second chromatographic column analysis system is respectively connected to the seventh valve port of the second injection valve and the fourth valve port of the second injection valve. The inlet end of the first pre-separation column is connected to the second valve port of the second injection valve, and the outlet end is connected to the sixth valve port of the second injection valve. The inlet end of the first chromatographic analysis column is connected to the fifth valve port of the second injection valve, and the third valve port of the second injection valve is connected to the hydrogen flame detector.

[0056] In the above natural gas product quality index analysis equipment, preferably, the third chromatographic column analysis system includes a third injection valve, and the third injection valve is a multi-way valve including a first gear and a second gear; in the third chromatographic column analysis system, the third injection valve is respectively communicated with both ends of the metering tube, communicated with the carrier gas pipe, and communicated with the chromatographic column, and the on-off of the connecting pipelines between the components in the third chromatographic column analysis system and the on-off of the connecting pipelines between the injection assembly and the third chromatographic column analysis system are controlled through the third injection valve;

[0057] When the third injection valve is switched to the first gear, it can realize that the gas in the injection assembly directly discharges from the third chromatographic column analysis system after passing through the metering tube; when the third injection valve is switched to the second gear, it can realize that the gas in the carrier gas pipe of the third chromatographic column analysis system flows through the metering tube of the third chromatographic column analysis system to the chromatographic column of the third chromatographic column analysis system;

[0058] More preferably, in the third chromatographic column analysis system, the third injection valve is respectively communicated with both ends of the metering tube, communicated with the carrier gas pipe, communicated with both ends of the second pre-separation column, and communicated with the inlet end of the second chromatographic analysis column, and the on-off of the connecting pipelines between the components in the third chromatographic column analysis system and the on-off of the connecting pipelines between the injection assembly and the third chromatographic column analysis system are controlled through the third injection valve;

[0059] When the third injection valve is switched to the first gear, it can realize that the gas in the injection assembly directly discharges from the third chromatographic column analysis system after passing through the metering tube, can realize that the gas in the carrier gas pipe of the third chromatographic column analysis system enters from the outlet end of the second pre-separation column and flows out from the inlet end of the second pre-separation column and then discharges from the three-analysis system, and can realize that the gas in the carrier gas pipe of the third chromatographic column analysis system enters the second chromatographic analysis column from the inlet end of the second chromatographic analysis column; when the third injection valve is switched to the second gear, it can realize that the gas in the carrier gas pipe of the third chromatographic column analysis system flows through the metering tube of the third chromatographic column analysis system to the second pre-separation column, enters from the inlet end of the second pre-separation column and flows out from the outlet end of the second pre-separation column, and then enters the second chromatographic analysis column through the inlet end of the second chromatographic analysis column;

[0060] Further preferably, the third injection valve is a ten-way valve including a first gear position and a second gear position. The third injection valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port, and a tenth valve port in a clockwise direction. When the third injection valve is in the first gear position, the tenth valve port communicates with the first valve port, the second valve port communicates with the third valve port, the fourth valve port communicates with the fifth valve port, the sixth valve port communicates with the seventh valve port, and the eighth valve port communicates with the ninth valve port. When the third injection valve is in the second gear position, the first valve port communicates with the second valve port, the third valve port communicates with the fourth valve port, the fifth valve port communicates with the sixth valve port, the seventh valve port communicates with the eighth valve port, and the ninth valve port communicates with the tenth valve port.

[0061] The tenth valve port and the ninth valve port of the third injection valve are respectively communicated with the injection assembly. One end of the quantitative tube of the third chromatographic column analysis system is communicated with the first valve port of the third injection valve, and the other end is communicated with the eighth valve port of the third injection valve. The carrier gas pipe of the third chromatographic column analysis system is respectively communicated with the seventh valve port of the third injection valve and the fourth valve port of the third injection valve. The inlet end of the second pre-separation column is communicated with the second valve port of the third injection valve, and the outlet end is communicated with the sixth valve port of the third injection valve. The inlet end of the second chromatographic analysis column is communicated with the fifth valve port of the third injection valve.

[0062] In the above natural gas product quality index analysis device, preferably, the fourth chromatographic column analysis system includes a fourth injection valve, and the fourth injection valve is a multi-way valve including a first gear position and a second gear position. In the fourth chromatographic column analysis system, the fourth injection valve is respectively communicated with both ends of the quantitative tube, the carrier gas pipe, and the chromatographic column. The on-off of the connecting pipelines between the components in the fourth chromatographic column analysis system and the on-off of the connecting pipeline between the injection assembly and the fourth chromatographic column analysis system are controlled by the fourth injection valve.

[0063] When the fourth injection valve is switched to the first gear position, the gas in the injection assembly can be directly discharged from the fourth chromatographic column analysis system after passing through the quantitative tube. When the fourth injection valve is switched to the second gear position, the gas in the carrier gas pipe of the fourth chromatographic column analysis system can flow through the quantitative tube of the fourth chromatographic column analysis system to the chromatographic column of the fourth chromatographic column analysis system.

[0064] More preferably, in the fourth chromatographic column analysis system, the fourth injection valve is respectively communicated with both ends of the quantitative tube, the carrier gas pipe, both ends of the third pre-separation column, and the inlet end of the third chromatographic analysis column. The on-off of the connecting pipelines between the components in the fourth chromatographic column analysis system and the on-off of the connecting pipeline between the injection assembly and the fourth chromatographic column analysis system are controlled by the fourth injection valve.

[0065] When the fourth injection valve is switched to the first gear, the gas in the injection assembly can be directly discharged from the fourth chromatographic column analysis system after passing through the metering tube. The gas in the carrier gas pipe of the fourth chromatographic column analysis system can enter from the outlet end of the third pre-separation column and flow out from the inlet end of the third pre-separation column and then be discharged from the three-analysis system. The gas in the carrier gas pipe of the fourth chromatographic column analysis system can enter the third chromatographic analysis column from the inlet end of the third chromatographic analysis column. When the fourth injection valve is switched to the second gear, the gas in the carrier gas pipe of the fourth chromatographic column analysis system can flow through the metering tube of the fourth chromatographic column analysis system to the third pre-separation column, enter from the inlet end of the third pre-separation column and flow out from the outlet end of the third pre-separation column, and then enter the third chromatographic analysis column from the inlet end of the third chromatographic analysis column.

[0066] Further preferably, the fourth injection valve is a ten-way valve including a first gear and a second gear. The fourth injection valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port, and a tenth valve port in a clockwise direction. When the fourth injection valve is in the first gear, the tenth valve port is connected to the first valve port, the second valve port is connected to the third valve port, the fourth valve port is connected to the fifth valve port, the sixth valve port is connected to the seventh valve port, and the eighth valve port is connected to the ninth valve port. When the fourth injection valve is in the second gear, the first valve port is connected to the second valve port, the third valve port is connected to the fourth valve port, the fifth valve port is connected to the sixth valve port, the seventh valve port is connected to the eighth valve port, and the ninth valve port is connected to the tenth valve port.

[0067] The tenth valve port and the ninth valve port of the fourth injection valve are respectively connected to the injection assembly. One end of the metering tube of the fourth chromatographic column analysis system is connected to the first valve port of the fourth injection valve, and the other end is connected to the eighth valve port of the fourth injection valve. The carrier gas pipe of the fourth chromatographic column analysis system is respectively connected to the seventh valve port of the fourth injection valve and the fourth valve port of the fourth injection valve. The inlet end of the third pre-separation column is connected to the second valve port of the fourth injection valve, and the outlet end is connected to the sixth valve port of the fourth injection valve. The inlet end of the third chromatographic analysis column is connected to the fifth valve port of the fourth injection valve.

[0068] In the above natural gas product quality index analysis equipment, preferably, the fifth chromatographic column analysis system includes a fifth injection valve, and the fifth injection valve is a multi-way valve including a first gear and a second gear. In the fifth chromatographic column analysis system, the fifth injection valve is respectively connected to both ends of the metering tube, the carrier gas pipe, and the chromatographic column. The fifth injection valve controls the on-off of the connecting pipelines between the components in the fifth chromatographic column analysis system and the on-off of the connecting pipelines between the injection assembly and the fifth chromatographic column analysis system.

[0069] When the fifth injection valve is switched to the first gear, the gas in the injection assembly can be directly discharged from the fifth chromatographic column analysis system after passing through the metering tube; when the fifth injection valve is switched to the second gear, the gas in the carrier gas pipe of the fifth chromatographic column analysis system can flow through the metering tube of the fifth chromatographic column analysis system into the chromatographic column of the fifth chromatographic column analysis system;

[0070] More preferably, in the fifth chromatographic column analysis system, the fifth injection valve is respectively connected to both ends of the metering tube, connected to the carrier gas pipe, connected to both ends of the fourth pre-separation column, and connected to the inlet end of the fourth chromatographic analysis column. The on-off of the connecting pipelines between various components in the fifth chromatographic column analysis system and the on-off of the connecting pipelines between the injection assembly and the fifth chromatographic column analysis system are controlled by the fifth injection valve;

[0071] When the fifth injection valve is switched to the first gear, the gas in the injection assembly can be directly discharged from the fifth chromatographic column analysis system after passing through the metering tube. The gas in the carrier gas pipe of the fifth chromatographic column analysis system can enter from the outlet end of the fourth pre-separation column and flow out from the inlet end of the fourth pre-separation column and then be discharged from the analysis system. The gas in the carrier gas pipe of the fifth chromatographic column analysis system can enter the fourth chromatographic analysis column from the inlet end of the fourth chromatographic analysis column; when the fifth injection valve is switched to the second gear, the gas in the carrier gas pipe of the fifth chromatographic column analysis system can flow through the metering tube of the fifth chromatographic column analysis system to the fourth pre-separation column, enter from the inlet end of the fourth pre-separation column and flow out from the outlet end of the fourth pre-separation column, and then enter the fourth chromatographic analysis column from the inlet end of the fourth chromatographic analysis column;

[0072] Further preferably, the fifth injection valve is a ten-way valve including a first gear and a second gear. The fifth injection valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port, and a tenth valve port in a clockwise direction; when the fifth injection valve is in the first gear, the tenth valve port is connected to the first valve port, the second valve port is connected to the third valve port, the fourth valve port is connected to the fifth valve port, the sixth valve port is connected to the seventh valve port, and the eighth valve port is connected to the ninth valve port; when the fifth injection valve is in the second gear, the first valve port is connected to the second valve port, the third valve port is connected to the fourth valve port, the fifth valve port is connected to the sixth valve port, the seventh valve port is connected to the eighth valve port, and the ninth valve port is connected to the tenth valve port;

[0073] The tenth valve port and the ninth valve port of the fifth injection valve are respectively communicated with the injection assembly. One end of the metering tube of the fifth chromatographic column analysis system is communicated with the first valve port of the fifth injection valve, and the other end is communicated with the eighth valve port of the fifth injection valve. The carrier gas pipe of the fifth chromatographic column analysis system is respectively communicated with the seventh valve port of the fifth injection valve and the fourth valve port of the fifth injection valve. The inlet end of the fourth pre-separation column is communicated with the second valve port of the fifth injection valve, and the outlet end is communicated with the sixth valve port of the fifth injection valve. The inlet end of the fourth chromatographic analysis column is communicated with the fifth valve port of the fifth injection valve.

[0074] In a specific embodiment, when the injection assembly includes a natural gas inlet pipe, a natural gas outlet pipe, and a first metering tube connecting pipe, a second metering tube connecting pipe, a third metering tube connecting pipe, and a fourth metering tube connecting pipe, the first metering tube connecting pipe, the second metering tube connecting pipe, the third metering tube connecting pipe, and the fourth metering tube connecting pipe are respectively used to connect the metering tubes in series. The natural gas inlet pipe is communicated with the inlet end of the metering tubes connected in series, and the natural gas outlet pipe is communicated with the outlet end of the metering tubes connected in series.

[0075] The first injection valve, the second injection valve, the third injection valve, the fourth injection valve, and the fifth injection valve are connected in series through the first metering tube connecting pipe, the second metering tube connecting pipe, the third metering tube connecting pipe, and the fourth metering tube connecting pipe. The natural gas inlet pipe and the natural gas outlet pipe are respectively connected to the first and last injection valves of the first injection valve, the second injection valve, the third injection valve, the fourth injection valve, and the fifth injection valve connected in series.

[0076] In the above natural gas product quality index analysis equipment, preferably, the equipment further includes a programmed temperature rising device, and the sulfur column of the first chromatographic column analysis system and / or the first chromatographic analysis column of the second chromatographic column analysis system are arranged in the programmed temperature rising device.

[0077] In the above natural gas product quality index analysis equipment, preferably, the equipment further includes a constant temperature device, and the second chromatographic analysis column of the third chromatographic column analysis system, the third chromatographic analysis column of the fourth chromatographic column analysis system, and / or the fourth chromatographic analysis column of the fifth chromatographic column analysis system are arranged in the constant temperature device.

[0078] In the above natural gas product quality index analysis equipment, preferably, the volume of the metering tube of the first chromatographic column analysis system is 1 mL.

[0079] In the above natural gas product quality index analysis equipment, preferably, the volume of the metering tube of the second chromatographic column analysis system is 100 μL.

[0080] In the above natural gas product quality index analysis equipment, preferably, the volume of the metering tube of the third chromatographic column analysis system is 1 mL.

[0081] In the above natural gas product quality index analysis device, preferably, the volume of the quantitative tube of the fourth chromatographic column analysis system is 1 mL.

[0082] In the above natural gas product quality index analysis device, preferably, the volume of the quantitative tube of the fifth chromatographic column analysis system is 5 mL.

[0083] The present invention also provides a method for analyzing the quality index of natural gas products. This method uses any of the above natural gas product quality index analysis devices. Among them, this method includes:

[0084] Inject samples into the quantitative tubes in the first chromatographic column analysis system, the second chromatographic column analysis system, the third chromatographic column analysis system, the fourth chromatographic column analysis system, and the fifth chromatographic column analysis system, so that each quantitative tube is filled with natural gas sample gas;

[0085] In the first chromatographic column analysis system, use a carrier gas pipe to transport the carrier gas. Driven by the carrier gas, the natural gas sample gas in the quantitative tube is separated for sulfides using a chromatographic column. The separated components are transported to a detector for detection to obtain a first detection spectrum; based on the obtained first detection spectrum, determine the sulfide content in the natural gas sample gas;

[0086] In the second chromatographic column analysis system, use a carrier gas pipe to transport the carrier gas. Driven by the carrier gas, the natural gas sample gas in the quantitative tube is separated for hydrocarbons above C3 using a chromatographic column. The separated components are transported to a detector for detection to obtain a second detection spectrum; based on the obtained second detection spectrum, determine the content of hydrocarbons above C3 in the natural gas sample gas;

[0087] In the third chromatographic column analysis system, use a carrier gas pipe to transport the carrier gas. Driven by the carrier gas, the natural gas sample gas in the quantitative tube is separated for oxygen, nitrogen, methane, and carbon monoxide using a chromatographic column. The separated components are transported to a detector for detection to obtain a third detection spectrum; based on the obtained third detection spectrum, determine the content of oxygen, nitrogen, methane, and carbon monoxide in the natural gas sample gas;

[0088] In the fourth chromatographic column analysis system, use a carrier gas pipe to transport the carrier gas. Driven by the carrier gas, the natural gas sample gas in the quantitative tube is separated for carbon dioxide and ethane using a chromatographic column. The separated components are transported to a detector for detection to obtain a fourth detection spectrum; based on the obtained fourth detection spectrum, determine the content of carbon dioxide and ethane in the natural gas sample gas;

[0089] In the fifth chromatographic column analysis system, use a carrier gas pipe to transport the carrier gas. Driven by the carrier gas, the natural gas sample gas in the quantitative tube is separated for helium and hydrogen using a chromatographic column. The separated components are transported to a detector for detection to obtain a fifth detection spectrum; based on the obtained fifth detection spectrum, determine the content of helium and hydrogen in the natural gas sample gas;

[0090] Based on the content of sulfides, the content of hydrocarbons with more than C3, the content of oxygen, nitrogen, methane and carbon monoxide, the content of carbon dioxide and ethane, and the content of helium and hydrogen in the obtained natural gas sample gas, determine the higher heating value of natural gas, the total sulfur content (calculated as sulfur, mg / m 3 ), the hydrogen sulfide content (mg / m 3 ) and / or the carbon dioxide content (mole percentage).

[0091] Using the integrated analysis equipment for natural gas product quality indicators disclosed in the present invention, equipped with an SCD detector, an FID detector, and a TCD detector, it is possible to complete the analysis of 13 sulfur compounds and 15 conventional components in natural gas products with a single injection, and the analysis cycle for completing the detection of all components with a single injection is less than 20 minutes.

[0092] In the above natural gas product quality indicator analysis method, based on the obtained first detection spectrum, the content of sulfides in the natural gas sample gas can be determined by using conventional methods in the art. For example, it can be determined by comparing the first detection spectrum with the standard curve of sulfide content. Specifically, the response peak area value data is obtained according to the first detection spectrum, and then the content of sulfides in the natural gas sample gas is determined by using the standard curve of sulfide content based on the response peak value data; among them, the standard curve of sulfide content can be obtained by detecting the standard gas sample.

[0093] In the above natural gas product quality indicator analysis method, based on the obtained second detection spectrum, the content of hydrocarbons with more than C3 in the natural gas sample gas can be determined by using conventional methods in the art. For example, it can be determined by comparing the second detection spectrum with the standard curve of the content of hydrocarbons with more than C3. Specifically, the response peak area value data is obtained according to the second detection spectrum, and then the content of hydrocarbons with more than C3 in the natural gas sample gas is determined by using the standard curve of the content of hydrocarbons with more than C3 based on the response peak value data; among them, the standard curve of the content of hydrocarbons with more than C3 can be obtained by detecting the standard gas sample.

[0094] In the above natural gas product quality indicator analysis method, based on the obtained third detection spectrum, the content of oxygen, nitrogen, methane and carbon monoxide in the natural gas sample gas can be determined by using conventional methods in the art. For example, it can be determined by comparing the third detection spectrum with the standard curve of the content of oxygen, nitrogen, methane and carbon monoxide. Specifically, the response peak area value data is obtained according to the third detection spectrum, and then the content of oxygen, nitrogen, methane and carbon monoxide in the natural gas sample gas is determined by using the standard curve of the content of oxygen, nitrogen, methane and carbon monoxide based on the response peak value data; among them, the standard curve of the content of oxygen, nitrogen, methane and carbon monoxide can be obtained by detecting the standard gas sample.

[0095] In the above natural gas product quality index analysis method, based on the obtained fourth detection spectrum, the contents of carbon dioxide and ethane in the natural gas sample gas can be determined by using conventional methods in the art. For example, the method of comparing the fourth detection spectrum with the standard curves of carbon dioxide and ethane contents can be adopted. Specifically, the response peak area value data is obtained according to the fourth detection spectrum, and then the contents of carbon dioxide and ethane in the natural gas sample gas are determined by using the standard curves of carbon dioxide and ethane contents based on the response peak value data; among them, the standard curves of carbon dioxide and ethane contents can be obtained by detecting the standard gas sample.

[0096] In the above natural gas product quality index analysis method, based on the obtained fifth detection spectrum, the contents of helium and hydrogen in the natural gas sample gas can be determined by using conventional methods in the art. For example, the method of comparing the fifth detection spectrum with the standard curves of helium and hydrogen contents can be adopted. Specifically, the response peak area value data is obtained according to the fifth detection spectrum, and then the contents of helium and hydrogen in the natural gas sample gas are determined by using the standard curves of helium and hydrogen contents based on the response peak value data; among them, the standard curves of helium and hydrogen contents can be obtained by detecting the standard gas sample.

[0097] In the above natural gas product quality index analysis method, the higher heating value of natural gas can be determined by using conventional methods in the art. For example, based on the contents of sulfides, hydrocarbons with more than C3, oxygen, nitrogen, methane and carbon monoxide, carbon dioxide and ethane, helium and hydrogen in the natural gas sample gas, the molar percentage content of sulfur compounds and the molar percentage content of hydrocarbons and non-hydrocarbons with a total of 100% are obtained, and then the higher heating value of natural gas is determined by using the higher heating value calculation model.

[0098] In the above natural gas product quality index analysis method, the total sulfur content of natural gas can be determined by using conventional methods in the art. For example, based on the content of sulfides in the natural gas sample gas, the sum of the contents of each sulfide is the total sulfur content of natural gas.

[0099] In the above natural gas product quality index analysis method, the hydrogen sulfide content of natural gas can be determined by using conventional methods in the art. For example, the content of hydrogen sulfide in the natural gas sample gas is the hydrogen sulfide content in natural gas.

[0100] In the above natural gas product quality index analysis method, the carbon dioxide content of natural gas can be determined by using conventional methods in the art. For example, based on the content of hydrocarbons with more than C3 in the natural gas sample gas, the content of oxygen, nitrogen, methane, and carbon monoxide in the natural gas sample gas, the content of carbon dioxide and ethane in the natural gas sample gas, and the content of helium and hydrogen in the natural gas sample gas, the sum of the contents of each component is obtained, and then based on the sum of the contents of each component, the proportion of the carbon dioxide content is determined, which is the carbon dioxide content in the natural gas.

[0101] In the above natural gas product quality index analysis method, preferably, in the first chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the quantitative tube is separated for sulfides using a chromatographic column, and the separated components are transported to a detector for detection. The steps for obtaining the first detection spectrum include:

[0102] In the first chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the quantitative tube is transported to a sulfur column for sulfide separation, and the separated components are transported to a sulfur chemiluminescence detector to detect the sulfides in the natural gas sample gas, obtaining the first detection spectrum;

[0103] In this preferred technical solution, driven by the carrier gas, the natural gas sample gas is separated using a sulfur column. Carbonyl sulfide, hydrogen sulfide, methanethiol, ethanethiol, methyl sulfide, methyl ethyl sulfide, dimethyl disulfide, ethyl sulfide, carbon disulfide, n-butyl mercaptan, tert-butyl mercaptan, isopropyl mercaptan, and thiophene in the sulfides are sequentially discharged from the sulfur column and enter the sulfur chemiluminescence detector for detection;

[0104] More preferably, the sulfur column is maintained at 30 - 50 °C until carbonyl sulfide leaves the sulfur column, and then it is heated to 130 - 150 °C at a rate of 10 - 20 °C / min and maintained;

[0105] In a specific embodiment, the flow rate of the carrier gas is 3 mL / min;

[0106] In a specific embodiment, the injection temperature of the sulfur chemiluminescence detector is 200 °C, the reaction temperature is 850 °C, and the flow rates of the reaction gases of the sulfur chemiluminescence detector are 80 mL / min of hydrogen (H2), 40 mL / min of nitrogen (N2), 10 mL / min of oxygen (O2), and 25 mL / min of ozone (O3).

[0107] In the above natural gas product quality index analysis method, preferably, in the second chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the quantitative tube is separated for hydrocarbons with more than C3 using a chromatographic column, and the separated components are transported to a detector for detection. The steps for obtaining the second detection spectrum include:

[0108] In the second chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the quantitative tube is separated successively using a first pre-separation column and a first chromatographic analysis column; when the C5 - component in the natural gas sample gas leaves the first pre-separation column and enters the first chromatographic analysis column, the carrier gas is transferred to the outlet end of the first pre-separation column, and the inlet end of the first pre-separation column is connected to a hydrogen flame detector. Under the drive of the carrier gas, the C6 + hydrocarbon components in the first pre-separation column are backflushed into the hydrogen flame detector for detection; after the backflushing is completed, the carrier gas is transferred to the inlet end of the first chromatographic analysis column. Under the drive of the carrier gas, each C3 - hydrocarbon component separated by the first chromatographic analysis column enters the hydrogen flame detector in sequence for detection; thus, a second detection chromatogram is obtained;

[0109] In this preferred technical solution, under the drive of the carrier gas, the natural gas sample gas is separated successively using a first pre-separation column and a first chromatographic analysis column. Propane, isobutane, n-butane, neopentane, isopentane, and n-pentane in the natural gas sample gas are discharged from the first pre-separation column and enter the first chromatographic analysis column for separation to increase the separation time difference between the components; after the C5 - component leaves the first pre-separation column and enters the first chromatographic analysis column, the carrier gas is transferred to the outlet end of the first pre-separation column, and the inlet end of the first pre-separation column is connected to a hydrogen flame detector. The C6 + and above hydrocarbon components in the first pre-separation column are first detected by passing through the hydrogen flame detector in the form of a hexane combined peak through the reverse flow direction of the carrier gas flow; then the carrier gas is transferred to the inlet end of the first chromatographic analysis column. Under the drive of the carrier gas, propane, isobutane, n-butane, neopentane, isopentane, and n-pentane are discharged from the first chromatographic analysis column in sequence and enter the hydrogen flame detector for detection;

[0110] More preferably, the first chromatographic analysis column is maintained at 30 - 50 °C until the hydrogen flame detector monitors the peak of the C6 + and above hydrocarbon components, and then heated at a rate of 10 - 20 °C / min to 130 - 150 °C and maintained;

[0111] In a specific embodiment, the carrier gas is injected at a pressure of 500 kPa;

[0112] In a specific embodiment, the temperature of the hydrogen flame detector is 200 °C, and the flow rates of the reaction gases of the hydrogen flame detector are 32 mL / min of hydrogen (H2), 200 mL / min of air, and 20 mL / min of make-up gas.

[0113] In the above natural gas product quality index analysis method, preferably, in the third chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the metering tube is separated into oxygen, nitrogen, methane, and carbon monoxide using a chromatographic column. The steps of transporting the separated components to a detector for detection to obtain a third detection chromatogram include:

[0114] In the third chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the metering tube is sequentially separated using a second pre-separation column and a second chromatographic analysis column; when the oxygen, nitrogen, methane, and carbon monoxide components in the natural gas sample gas leave the second pre-separation column and enter the second chromatographic analysis column, the carrier gas is transferred to the outlet end of the second pre-separation column, and the remaining components in the second pre-separation column are blown out of the third chromatographic column analysis system by the reverse flow of the carrier gas; after the backflush is completed, the carrier gas is transferred to the inlet end of the second chromatographic analysis column, and the oxygen, nitrogen, methane, and carbon monoxide components separated by the second chromatographic analysis column are sequentially introduced into a thermal conductivity detector for detection; thereby obtaining a third detection chromatogram;

[0115] In this preferred technical solution, driven by the carrier gas, the natural gas sample gas is sequentially separated using a second pre-separation column and a second chromatographic analysis column. The oxygen, nitrogen, methane, and carbon monoxide in the natural gas sample gas are discharged from the second pre-separation column and enter the second chromatographic analysis column for separation to increase the separation time difference between the components; after the oxygen, nitrogen, methane, and carbon monoxide components leave the second pre-separation column and enter the second chromatographic analysis column, the carrier gas is transferred to the outlet end of the second pre-separation column, and the remaining components in the second pre-separation column are removed by the reverse flow of the carrier gas; then the carrier gas is transferred to the inlet end of the second chromatographic analysis column, and the oxygen, nitrogen, methane, and carbon monoxide are sequentially discharged from the second chromatographic analysis column and introduced into a thermal conductivity detector for detection;

[0116] More preferably, the column temperature of the second chromatographic analysis column is 50-70°C;

[0117] In a specific embodiment, the carrier gas is injected at a pressure of 295-500 kPa;

[0118] In a specific embodiment, the temperature of the thermal conductivity detector is 150°C, the working current of the thermal conductivity detector is 120 mA, and the polarity is cathode.

[0119] In the above natural gas product quality index analysis method, preferably, in the fourth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the metering tube is separated into carbon dioxide and ethane using a chromatographic column. The steps of transporting the separated components to a detector for detection to obtain a fourth detection chromatogram include:

[0120] In the fourth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the quantitative tube is separated successively using a third pre-separation column and a third chromatographic analysis column. After the carbon dioxide and ethane components in the natural gas sample gas leave the third pre-separation column and enter the third chromatographic analysis column, the carrier gas is transferred to the outlet end of the third pre-separation column, and the remaining components in the third pre-separation column are back-flushed out of the fourth chromatographic column analysis system under the drive of the carrier gas. After the back-flushing is completed, the carrier gas is transferred to the inlet end of the third chromatographic analysis column, and the carbon dioxide and ethane components separated by the third chromatographic analysis column enter the thermal conductivity detector in sequence under the drive of the carrier gas for detection, thereby obtaining a fourth detection spectrum.

[0121] In this preferred technical solution, under the drive of the carrier gas, the natural gas sample gas is separated successively using a third pre-separation column and a third chromatographic analysis column. The carbon dioxide and ethane in the natural gas sample gas are discharged from the third pre-separation column and enter the third chromatographic analysis column for separation, increasing the separation time difference between the components. After the carbon dioxide and ethane components leave the third pre-separation column and enter the third chromatographic analysis column, the carrier gas is transferred to the outlet end of the third pre-separation column, and the remaining components in the third pre-separation column are removed by reverse blowing through the carrier gas flow. Then the carrier gas is transferred to the inlet end of the third chromatographic analysis column, and under the drive of the carrier gas, the carbon dioxide and ethane are discharged from the third chromatographic analysis column in sequence and enter the thermal conductivity detector for detection.

[0122] More preferably, the column temperature of the third chromatographic analysis column is 50 - 70 °C.

[0123] In a specific embodiment, the carrier gas is injected at a pressure of 278 - 350 kPa.

[0124] In a specific embodiment, the temperature of the thermal conductivity detector is 150 °C, the working current of the thermal conductivity detector is 120 mA, and the polarity is cathode.

[0125] In the above method for analyzing the quality index of natural gas products, preferably, in the fifth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the quantitative tube is separated into helium and hydrogen using a chromatographic column, and the separated components are transported to a detector for detection. The steps for obtaining a fifth detection spectrum include:

[0126] In the fifth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the metering tube is separated successively using a fourth pre-separation column and a fourth chromatographic analysis column. After the helium and hydrogen components in the natural gas sample gas leave the fourth pre-separation column and enter the fourth chromatographic analysis column, the carrier gas is transferred to the outlet end of the fourth pre-separation column, and the remaining components in the fourth pre-separation column are blown out of the fifth chromatographic column analysis system under the drive of the carrier gas. After the back-flushing is completed, the carrier gas is transferred to the inlet end of the fourth chromatographic analysis column, and under the drive of the carrier gas, the helium and hydrogen components separated by the fourth chromatographic analysis column enter a thermal conductivity detector for detection in sequence, thereby obtaining a fifth detection spectrum.

[0127] In this preferred technical solution, under the drive of the carrier gas, the natural gas sample gas is separated successively using a fourth pre-separation column and a fourth chromatographic analysis column. The helium and hydrogen in the natural gas sample gas are discharged from the fourth pre-separation column and enter the fourth chromatographic analysis column for separation, increasing the separation time difference between the components. After the helium and hydrogen components leave the fourth pre-separation column and enter the fourth chromatographic analysis column, the carrier gas is transferred to the outlet end of the fourth pre-separation column, and the remaining components in the fourth pre-separation column are removed by back-blowing in the reverse direction of the carrier gas flow. Then the carrier gas is transferred to the inlet end of the fourth chromatographic analysis column, and under the drive of the carrier gas, the helium and hydrogen are discharged from the fourth chromatographic analysis column in sequence and enter a thermal conductivity detector for detection.

[0128] More preferably, the column temperature of the fourth chromatographic analysis column is 50 - 70 °C.

[0129] In a specific embodiment, the carrier gas is injected at a pressure of 250 kPa.

[0130] In a specific embodiment, the temperature of the thermal conductivity detector is 150 °C, the working current of the thermal conductivity detector is 70 mA, and the polarity is anodic.

[0131] In the above method for analyzing the quality index of natural gas products, preferably, the carrier gas used in the first chromatographic column analysis system is helium.

[0132] In the above method for analyzing the quality index of natural gas products, preferably, the carrier gas used in the second chromatographic column analysis system is helium.

[0133] In the above method for analyzing the quality index of natural gas products, preferably, the carrier gas used in the third chromatographic column analysis system is helium.

[0134] In the above method for analyzing the quality index of natural gas products, preferably, the carrier gas used in the fourth chromatographic column analysis system is helium.

[0135] In the above method for analyzing the quality index of natural gas products, preferably, the carrier gas used in the fifth chromatographic column analysis system is nitrogen.

[0136] The present invention also provides an application of the above natural gas product quality index analysis device in the analysis of natural gas products. BRIEF DESCRIPTION OF THE DRAWINGS

[0137] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts:

[0138] Figure 1 It is a schematic structural diagram of the natural gas product quality index analysis device in Embodiment 1 of the present invention.

[0139] Figure 2 It is a schematic structural diagram of the first chromatographic column analysis system in Embodiment 1 of the present invention.

[0140] Figure 3 It is a schematic structural diagram of the second chromatographic column analysis system in Embodiment 1 of the present invention.

[0141] Figure 4 It is a schematic structural diagram of the third chromatographic column analysis system in Embodiment 1 of the present invention.

[0142] Figure 5 It is a schematic structural diagram of the fourth chromatographic column analysis system in Embodiment 1 of the present invention.

[0143] Figure 6 It is a schematic structural diagram of the fifth chromatographic column analysis system in Embodiment 1 of the present invention.

[0144] Figure 7 It is the first detection spectrum in Embodiment 2 of the present invention.

[0145] Figure 8 It is the second detection spectrum in Embodiment 2 of the present invention.

[0146] Figure 9 It is the third and fourth detection spectra in Embodiment 2 of the present invention.

[0147] Figure 10 It is the fifth detection spectrum in Embodiment 2 of the present invention.

[0148] Figure 11 It is the standard curve of hydrogen sulfide content.

[0149] Figure 12 It is the standard curve of carbonyl sulfide content.

[0150] Figure 13 It is the standard curve of methanethiol content.

[0151] Figure 14 It is the standard curve of ethyl mercaptan content.

[0152] Figure 15 It is the standard curve of dimethyl sulfide content.

[0153] Figure 16 It is the standard curve of carbon disulfide content.

[0154] Figure 17 It is the standard curve of isopropyl mercaptan content.

[0155] Figure 18 It is the standard curve of tert-butyl mercaptan content.

[0156] Figure 19 It is the standard curve of methylethyl sulfide content.

[0157] Figure 20 It is the standard curve of thiophene content.

[0158] Figure 21 It is the standard curve of diethyl sulfide content.

[0159] Figure 22 It is the standard curve of n-butyl mercaptan content.

[0160] Figure 23 It is the standard curve of dimethyl disulfide content.

[0161] Figure 24 It is the standard curve of carbon dioxide content.

[0162] Figure 25 It is the standard curve of ethane content.

[0163] Figure 26 It is the standard curve of nitrogen content.

[0164] Figure 27 It is the standard curve of helium content.

[0165] Figure 28 It is the standard curve of hydrogen content.

[0166] Figure 29 It is the standard curve of hexane content.

[0167] Figure 30 It is the standard curve of propane content.

[0168] Figure 31 It is the standard curve of carbon monoxide content.

[0169] Figure 32 It is the standard curve of isobutane content.

[0170] Figure 33 It is the standard curve of n-butane content.

[0171] Figure 34 It is the standard curve of neopentane content.

[0172] Figure 35 It is the standard curve of isopentane content.

[0173] Figure 36 It is the standard curve of n-pentane content.

[0174] Main reference numerals description:

[0175] 1 Sampling assembly; 11 Natural gas inlet pipe; 12 Natural gas outlet pipe; 13 First quantitative tube connecting pipe; 14 Second quantitative tube connecting pipe; 15 Third quantitative tube connecting pipe; 16 Fourth quantitative tube connecting pipe;

[0176] 21 First chromatographic column analysis system; 211 First injection valve; 212 First quantitative tube; 213 First carrier gas pipe; 214 Sulfur column; 215 Split / splitless injection port;

[0177] 22 Second chromatographic column analysis system; 221 Second injection valve; 222 Second quantitative tube; 223 Second carrier gas pipe; 224 First pre-separation column; 225 First chromatographic analysis column;

[0178] 23 Third chromatographic column analysis system; 231 Third injection valve; 232 Third quantitative tube; 233 Third carrier gas pipe; 234 Second pre-separation column; 235 Second chromatographic analysis column;

[0179] 24 Fourth chromatographic column analysis system; 241 Fourth injection valve; 242 Fourth quantitative tube; 243 Fourth carrier gas pipe; 244 Third pre-separation column; 245 Third chromatographic analysis column;

[0180] 25 Fifth chromatographic column analysis system; 251 Fifth injection valve; 252 Fifth quantitative tube; 253 Fifth carrier gas pipe; 254 Fourth pre-separation column; 255 Fourth chromatographic analysis column;

[0181] 31 Sulfur chemiluminescence detector; 32 Hydrogen flame detector; 33 First thermal conductivity detector; 34 Second thermal conductivity detector. Detailed implementation manners

[0182] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0183] The principles and spirit of the present invention will be described in detail below with reference to several representative embodiments of the present invention.

[0184] Embodiment 1

[0185] As Figures 1 - 6 shown, this embodiment provides an analysis device for natural gas product quality indicators. The system includes: a sample injection assembly 1, a first chromatographic column analysis system 21, a second chromatographic column analysis system 22, a third chromatographic column analysis system 23, a fourth chromatographic column analysis system 24, a fifth chromatographic column analysis system 25, a sulfur chemiluminescence detector 31, a hydrogen flame detector 32, a first thermal conductivity detector 33, and a second thermal conductivity detector 34;

[0186] Among them, the sample injection assembly 1 includes a natural gas inlet pipe 11, a natural gas outlet pipe 12, a first quantitative tube connecting pipe 13, a second quantitative tube connecting pipe 14, a third quantitative tube connecting pipe 15, and a fourth quantitative tube connecting pipe 16;

[0187] Among them, each chromatographic column analysis system includes an injection valve and a quantitative tube, a carrier gas pipe, and a chromatographic column connected to the injection valve; specifically:

[0188] The first chromatographic column analysis system 21 includes a first injection valve 211, a first quantitative tube 212, a first carrier gas pipe 213, a sulfur column 214, and a split / splitless injection port 215; the first injection valve 211 is a six-way valve including a first gear and a second gear, and is provided with a first valve port a1, a second valve port a2, a third valve port a3, a fourth valve port a4, a fifth valve port a5, and a sixth valve port a6 in a clockwise direction; when the first injection valve 211 is in the first gear, the sixth valve port a6 is connected to the first valve port a1, the second valve port a2 is connected to the third valve port a3, and the fourth valve port a4 is connected to the fifth valve port a5; when the first injection valve 211 is in the second gear, the first valve port a1 is connected to the second valve port a2, the third valve port a3 is connected to the fourth valve port a4, and the fifth valve port a5 is connected to the sixth valve port a6; one end of the first quantitative tube 212 is connected to the first valve port a1, and the other end is connected to the fourth valve port a4. The first carrier gas pipe 213 is connected to the second valve port a2, and the sulfur column 214 is connected to the third valve port a3; the split / splitless injection port 215 is provided on the connecting pipeline between the sulfur column 214 and the third valve port a3; among them, the sulfur column 214 can separate carbonyl sulfide, hydrogen sulfide, methyl mercaptan, ethyl mercaptan, methyl sulfide, methyl ethyl sulfide, dimethyl disulfide, ethyl sulfide, carbon disulfide, n-butyl mercaptan, tert-butyl mercaptan, isopropyl mercaptan, and thiophene; among them, a flow controller 2131 is provided on the first carrier gas pipe 213;

[0189] The second chromatographic column analysis system 22 includes a second injection valve 221, a second metering tube 222, a second carrier gas pipe 223, a first pre-separation column 224, and a first chromatographic analysis column 225; the second injection valve 222 is a ten-port valve including a first gear position and a second gear position, and is provided with a first valve port b1, a second valve port b2, a third valve port b3, a fourth valve port b4, a fifth valve port b5, a sixth valve port b6, a seventh valve port b7, an eighth valve port b8, a ninth valve port b9, and a tenth valve port b10 in a clockwise direction; when the second injection valve 221 is in the first gear position, the tenth valve port b10 is communicated with the first valve port b1, the second valve port b2 is communicated with the third valve port b3, the fourth valve port b4 is communicated with the fifth valve port b5, the sixth valve port b6 is communicated with the seventh valve port b7, and the eighth valve port b8 is communicated with the ninth valve port b9; when the second injection valve 221 is in the second gear position, the first valve port b1 is communicated with the second valve port b2, the third valve port b3 is communicated with the fourth valve port b4, the fifth valve port b5 is communicated with the sixth valve port b6, the seventh valve port b7 is communicated with the eighth valve port b8, and the ninth valve port b9 is communicated with the tenth valve port b10; one end of the second metering tube 222 is communicated with the first valve port b1, and the other end is communicated with the eighth valve port b8, the second carrier gas pipe 223 is respectively communicated with the seventh valve port b7 and the fourth valve port b4, the inlet end of the first pre-separation column 224 is communicated with the second valve port b2, and the outlet end is communicated with the sixth valve port b6, and the inlet end of the first chromatographic analysis column 225 is communicated with the fifth valve port b5; wherein, the first pre-separation column 224 can separate hydrocarbon components containing 6 or more carbon atoms (hydrocarbon components with 6 or more carbons) from hydrocarbon components containing 5 or less carbon atoms (hydrocarbon components with 5 or less carbons), and the first chromatographic analysis column 225 can separate propane, isobutane, n-butane, neopentane, isopentane, and n-pentane; wherein, the second carrier gas pipe 223 is provided with a flow controller 2231; wherein, a damping tube 227 is arranged on the connecting pipeline between the second carrier gas pipe 223 and the fourth valve port b4; wherein, a shunt valve 229 is arranged on the connecting pipeline between the inlet end of the first chromatographic analysis column 225 and the fifth valve port b5; + of hydrocarbon components (hydrocarbon components containing more than 6 carbons) from C5 - of hydrocarbon components (hydrocarbon components containing 5 or less carbons);

[0190] The third chromatographic column analysis system 23 includes a third injection valve 231, a third metering tube 232, a third carrier gas pipe 233, a second pre-separation column 234 and a second chromatographic analysis column 235; the third injection valve 231 is a ten-way valve including a first gear position and a second gear position, and is provided with a first valve port c1, a second valve port c2, a third valve port c3, a fourth valve port c4, a fifth valve port c5, a sixth valve port c6, a seventh valve port c7, an eighth valve port c8, a ninth valve port c9 and a tenth valve port c10 in a clockwise direction; when the third injection valve 231 is in the first gear position, the tenth valve port c10 is communicated with the first valve port c1, the second valve port c2 is communicated with the third valve port c3, the fourth valve port c4 is communicated with the fifth valve port c5, the sixth valve port c6 is communicated with the seventh valve port c7, and the eighth valve port c8 is communicated with the ninth valve port c9; when the third injection valve 231 is in the second gear position, the first valve port c1 is communicated with the second valve port c2, the third valve port c3 is communicated with the fourth valve port c4, the fifth valve port c5 is communicated with the sixth valve port c6, the seventh valve port c7 is communicated with the eighth valve port c8, and the ninth valve port c9 is communicated with the tenth valve port c10; one end of the third metering tube 232 is communicated with the first valve port c1, and the other end is communicated with the eighth valve port c8. The third carrier gas pipe 233 is respectively communicated with the seventh valve port c7 and the fourth valve port c4. The inlet end of the second pre-separation column 234 is communicated with the second valve port c2, and the outlet end is communicated with the sixth valve port c6. The inlet end of the second chromatographic analysis column 235 is communicated with the fifth valve port c5; the third valve port c3 is used as the backflush exhaust port of the second pre-separation column 234; wherein, the second pre-separation column 234 can separate oxygen, nitrogen, methane and carbon monoxide from natural gas (other hydrocarbon components in natural gas can be backflushed out), and the second chromatographic analysis column 235 can separate oxygen, nitrogen, methane and carbon monoxide; wherein, a flow controller 2331 is arranged on the third carrier gas pipe 233, and a damping pipe 237 is arranged on the connecting pipeline between the third carrier gas pipe 233 and the fourth valve port c4; a damping pipe 236 is arranged on the external exhaust pipeline connecting the third valve port c3;

[0191] The fourth chromatographic column analysis system 24 includes a fourth injection valve 241, a fourth metering tube 242, a fourth carrier gas pipe 243, a third pre-separation column 244, and a third chromatographic analysis column 245; the fourth injection valve 241 is a ten-way valve including a first gear position and a second gear position, and is provided with a first valve port d1, a second valve port d2, a third valve port d3, a fourth valve port d4, a fifth valve port d5, a sixth valve port d6, a seventh valve port d7, an eighth valve port d8, a ninth valve port d9, and a tenth valve port d10 in a clockwise direction; when the fourth injection valve 241 is in the first gear position, the tenth valve port d10 is communicated with the first valve port d1, the second valve port d2 is communicated with the third valve port d3, the fourth valve port d4 is communicated with the fifth valve port d5, the sixth valve port d6 is communicated with the seventh valve port d7, and the eighth valve port d8 is communicated with the ninth valve port d9; when the fourth injection valve 241 is in the second gear position, the first valve port d1 is communicated with the second valve port d2, the third valve port d3 is communicated with the fourth valve port d4, the fifth valve port d5 is communicated with the sixth valve port d6, the seventh valve port d7 is communicated with the eighth valve port d8, and the ninth valve port d9 is communicated with the tenth valve port d10; one end of the fourth metering tube 242 is communicated with the first valve port d1, and the other end is communicated with the eighth valve port d8. The fourth carrier gas pipe 243 is respectively communicated with the seventh valve port d7 and the fourth valve port d4. The inlet end of the third pre-separation column 244 is communicated with the second valve port d2, and the outlet end is communicated with the sixth valve port d6. The inlet end of the third chromatographic analysis column 245 is communicated with the fifth valve port d5; the third valve port d3 is used as a backflush exhaust port of the third pre-separation column 244; wherein, the third pre-separation column 244 can separate ethane and CO2 from natural gas, and the third chromatographic analysis column 245 can separate ethane and CO2; wherein, a flow controller 2431 is provided on the fourth carrier gas pipe 243; wherein, a damping tube 247 is provided on the connecting pipeline between the fourth carrier gas pipe 243 and the fourth valve port d4; a damping tube 246 is provided on the external exhaust pipeline connecting the third valve port d3;

[0192] The fifth chromatographic column analysis system 25 includes a fifth injection valve 251, a fifth metering tube 252, a fifth carrier gas pipe 253, a fourth pre-separation column 254, and a fourth chromatographic analysis column 255; the fifth injection valve 251 is a ten-way valve including a first gear position and a second gear position, and is provided with a first valve port e1, a second valve port e2, a third valve port e3, a fourth valve port e4, a fifth valve port e5, a sixth valve port e6, a seventh valve port e7, an eighth valve port e8, a ninth valve port e9, and a tenth valve port e10 in a clockwise direction; when the fifth injection valve 251 is in the first gear position, the tenth valve port e10 is communicated with the first valve port e1, the second valve port e2 is communicated with the third valve port e3, the fourth valve port e4 is communicated with the fifth valve port e5, the sixth valve port e6 is communicated with the seventh valve port e7, and the eighth valve port e8 is communicated with the ninth valve port e9; when the fifth injection valve 251 is in the second gear position, the first valve port e1 is communicated with the second valve port e2, the third valve port e3 is communicated with the fourth valve port e4, the fifth valve port e5 is communicated with the sixth valve port e6, the seventh valve port e7 is communicated with the eighth valve port e8, and the ninth valve port e9 is communicated with the tenth valve port e10; one end of the fifth metering tube 252 is communicated with the first valve port e1, and the other end is communicated with the eighth valve port e8, the fifth carrier gas pipe 253 is respectively communicated with the seventh valve port e7 and the fourth valve port e4, the inlet end of the fourth pre-separation column 254 is communicated with the second valve port e2, and the outlet end is communicated with the sixth valve port e6, and the inlet end of the fourth chromatographic analysis column 255 is communicated with the fifth valve port e5; the third valve port e3 is used as the backflush exhaust port of the fourth pre-separation column 254; wherein, the fourth pre-separation column 254 can separate helium and hydrogen from natural gas (other hydrocarbon components in natural gas can be backflushed out), and the fourth chromatographic analysis column 255 can separate helium and hydrogen; wherein, a flow controller 2531 is provided on the fifth carrier gas pipe 253; wherein, a damping tube 257 is provided on the connecting pipeline between the fifth carrier gas pipe 253 and the fourth valve port e4; a damping tube 256 is provided on the external exhaust pipeline connecting the third valve port e3; wherein, the first injection valve 211, the second injection valve 221, the third injection valve 231, the fourth injection valve 241, and the fifth injection valve 251 are connected in series through a first metering tube connecting pipe 13, a second metering tube connecting pipe 14, a third metering tube connecting pipe 15, and a fourth metering tube connecting pipe 16, and a natural gas inlet pipe 11 and a natural gas outlet pipe 12 are respectively connected to the first and last injection valves of the first injection valve 211, the second injection valve 221, the third injection valve 231, the fourth injection valve 241, and the fifth injection valve 251 connected in series, so as to realize the series connection of each metering tube; specifically:

[0193] The sixth valve port a6 of the first injection valve 211 is connected to the natural gas inlet pipe 11, the fifth valve port a5 of the first injection valve 211 is connected to the first metering tube connecting pipe 13, the tenth valve port b10 of the second injection valve 221 is connected to the first metering tube connecting pipe 13, the ninth valve port b9 of the second injection valve 221 is connected to the second metering tube connecting pipe 14, the tenth valve port c10 of the third injection valve 231 is connected to the second metering tube connecting pipe 14, the ninth valve port c9 of the third injection valve 231 is connected to the third metering tube connecting pipe 15, the tenth valve port d10 of the fourth injection valve 241 is connected to the third metering tube connecting pipe 15, the ninth valve port d9 of the fourth injection valve 241 is connected to the fourth metering tube connecting pipe 16, the tenth valve port e10 of the fifth injection valve 251 is connected to the fourth metering tube connecting pipe 16, and the ninth valve port e9 of the fifth injection valve 251 is connected to the natural gas outlet pipe 12; wherein, a control valve 111 is provided on the natural gas inlet pipe 11; wherein, a control valve 141 is provided on the second metering tube connecting pipe 14; wherein, a control valve 151 is provided on the third metering tube connecting pipe 15;

[0194] Wherein, each chromatographic column analysis system is respectively connected to a corresponding detector; specifically:

[0195] The sulfur chemiluminescence detector 31 is connected to the outlet end of the sulfur column 214, the third valve port b3 of the second injection valve 221 and the first chromatographic analysis column 225 are respectively connected to the hydrogen flame detector 32, the second chromatographic analysis column 235 is connected to the first thermal conductivity detector 33, the third chromatographic analysis column 245 is connected to the first thermal conductivity detector 33, and the fourth chromatographic analysis column 255 and the fifth carrier gas pipe 253 are respectively connected to the second thermal conductivity detector 34; wherein, a shunt valve 228 and a damping tube 226 are provided on the connecting pipeline between the third valve port b3 of the second injection valve 221 and the hydrogen flame detector 32; wherein, a damping tube 258 is provided on the connecting pipeline between the fifth carrier gas pipe 253 and the second thermal conductivity detector 34;

[0196] Wherein, the first chromatographic column analysis system 21 is used to separate carbonyl sulfide, hydrogen sulfide, methanethiol, ethanethiol, methyl sulfide, methyl ethyl sulfide, dimethyl disulfide, ethyl sulfide, carbon disulfide, n-butyl mercaptan, tert-butyl mercaptan, isopropyl mercaptan and thiophene in natural gas, and the first chromatographic column analysis system 21 is connected to the sulfur chemiluminescence detector 31 to realize the content analysis of carbonyl sulfide, hydrogen sulfide, methanethiol, ethanethiol, methyl sulfide, methyl ethyl sulfide, dimethyl disulfide, ethyl sulfide, carbon disulfide, n-butyl mercaptan, tert-butyl mercaptan, isopropyl mercaptan and thiophene in natural gas;

[0197] The second chromatographic column analysis system 22 is used to separate hydrocarbons with more than C3 in natural gas, and the second chromatographic column analysis system 22 is connected to the hydrogen flame detector 32 to realize the content analysis of hydrocarbons with more than C3 in natural gas;

[0198] The third chromatographic column analysis system 23 is used to separate oxygen, nitrogen, methane, and carbon monoxide in natural gas. The third chromatographic column analysis system 23 is connected to the first thermal conductivity detector 33 to analyze the contents of oxygen, nitrogen, methane, and carbon monoxide in natural gas;

[0199] The fourth chromatographic column analysis system 24 is used to separate carbon dioxide and ethane in natural gas. The fourth chromatographic column analysis system 24 is connected to the first thermal conductivity detector 33 to analyze the contents of carbon dioxide and ethane in natural gas;

[0200] The fifth chromatographic column analysis system 25 is used to separate helium and hydrogen in natural gas. The fifth chromatographic column analysis system 25 is connected to the second thermal conductivity detector 34 to analyze the contents of helium and hydrogen in natural gas.

[0201] Specifically, the sulfur column 214 selects a DB-Sulfur SCD chromatographic column; the size of the sulfur column 214 is 60 m in length, 0.32 mm in diameter, and 4.2 μm in capillary column liquid film thickness;

[0202] The volume of the first metering tube 212 is 1 mL.

[0203] Specifically, the first pre-separation column 224 selects an OV-1 pre-separation column; the packing material of the first pre-separation column 224 includes diatomaceous earth 545 with a mesh size of 80 - 100 and silicone OV-1. Based on the mass of diatomaceous earth 545, the content of silicone OV-1 is 10% (Silicone OV-1 10% Celite545 80 / 100mesh); the size of the first pre-separation column 224 is 1.6 mm in outer diameter, 1.0 mm in inner diameter, and 1.0 m in length;

[0204] The first chromatographic analysis column 225 selects an HP-Al / S chromatographic column; the size of the first chromatographic analysis column 225 is 50 m in length, 0.53 mm in diameter, and 15 μm in liquid film thickness;

[0205] The volume of the second metering tube 222 is 0.1 mL.

[0206] Specifically, the second pre-separation column 234 selects a Porapak N column; the mesh size of the packing material of the second pre-separation column 234 is 80 - 100; the size of the second pre-separation column 234 is 3.2 mm in outer diameter, 2.1 mm in inner diameter, and 1.0 m in length;

[0207] The second chromatographic analysis column 235 selects an MS-13X molecular sieve column; the size of the second chromatographic analysis column 235 is 3.2 mm in outer diameter, 2.1 mm in inner diameter, and 5.0 m in length;

[0208] The volume of the third metering tube 232 is 1 mL.

[0209] Specifically, the third pre-separation column 244 is a Porapak N column; the mesh number of the packing material of the third pre-separation column 244 is 80 - 100 meshes; the size of the third pre-separation column 244 is an outer diameter of 3.2 mm, an inner diameter of 2.1 mm, and a length of 1.0 m;

[0210] The third chromatographic analysis column 245 is a Porapak N column; the mesh number of the packing material of the third chromatographic analysis column 245 is 80 - 100 meshes; the size of the third chromatographic analysis column 245 is an outer diameter of 3.2 mm, an inner diameter of 2.1 mm, and a length of 2.0 m;

[0211] The volume of the fourth metering tube 242 is 1 mL.

[0212] Specifically, the fourth pre-separation column 254 is a Porapak N column; the mesh number of the packing material of the fourth pre-separation column 254 is 80 - 100 meshes; the size of the fourth pre-separation column 254 is an outer diameter of 3.2 mm, an inner diameter of 2.1 mm, and a length of 1.0 m;

[0213] The fourth chromatographic analysis column 255 is an MS-5A molecular sieve column. The mesh number of the packing material of the fourth chromatographic analysis column 255 is 60 - 80 meshes; the size of the fourth chromatographic analysis column 255 is an outer diameter of 3.2 mm, an inner diameter of 2.1 mm, and a length of 3.0 m;

[0214] The volume of the fifth metering tube 252 is 5 mL.

[0215] Specifically, the device further includes a temperature programming device, and the sulfur column 214 and the first chromatographic analysis column 225 are arranged in the temperature programming device.

[0216] Specifically, the device further includes a constant temperature device, and the second chromatographic analysis column 235, the third chromatographic analysis column 245, and the fourth chromatographic analysis column 255 are arranged in the constant temperature device.

[0217] Example 2

[0218] This example also provides a method for analyzing the quality index of natural gas products. This method is carried out using the natural gas product quality index analysis device provided in Example 1. This method includes:

[0219] Step S1: Inject samples into the metering tubes in the first chromatographic column analysis system 21, the second chromatographic column analysis system 22, the third chromatographic column analysis system 23, the fourth chromatographic column analysis system 24, and the fifth chromatographic column analysis system 25, so that each metering tube is filled with natural gas sample gas; specifically:

[0220] Switch the first sampling valve 211, the second sampling valve 221, the third sampling valve 231, the fourth sampling valve 241, and the fifth sampling valve 251 to the first gear, and then introduce natural gas products from the natural gas inlet pipe 11 into the first sampling valve 211. The natural gas products sequentially pass through the first metering tube 212, the second metering tube 232, the third metering tube 232, the fourth metering tube 242, and the fifth metering tube 252, and then are discharged from the natural gas outlet pipe 12. The first metering tube 212, the second metering tube 232, the third metering tube 232, the fourth metering tube 242, and the fifth metering tube 252 intercept part of the natural gas products as natural gas sample gas.

[0221] Step S2: In the first chromatographic column analysis system 21, use the first carrier gas pipe 213 to transport the carrier gas. Under the drive of the carrier gas, transport the natural gas sample gas in the first metering tube 212 to the sulfur column 214 for sulfide separation. The separated components are transported to the sulfur chemiluminescence detector 31 to detect the sulfides in the natural gas sample gas and obtain the first detection spectrum. Specifically:

[0222] Switch the first sampling valve 211 in the first chromatographic column analysis system 21 to the second gear. The carrier gas is introduced into the first chromatographic column analysis system 21 through the first carrier gas pipe 213 at a flow rate of 3 mL / min. The carrier gas sequentially passes through the second valve port a2 and the first valve port a1 and enters the first metering tube 212, driving the natural gas sample gas in the first metering tube 212 to flow, and sequentially passes through the fourth valve port a4, the third valve port a3, and the split / splitless injection port 215 and then enters the sulfur column 214 for separation. Carbonyl sulfide, hydrogen sulfide, methanethiol, ethanethiol, methyl sulfide, methyl ethyl sulfide, dimethyl disulfide, ethyl sulfide, carbon disulfide, n-butyl mercaptan, tert-butyl mercaptan, isopropyl mercaptan, and thiophene are sequentially discharged from the sulfur column 214 and enter the sulfur chemiluminescence detector 31 for detection to obtain the first detection spectrum. The first detection spectrum is shown in Figure 7 ;

[0223] Among them, the carrier gas is helium;

[0224] The sulfur column 214 is maintained at 40 °C until carbonyl sulfide leaves the sulfur column (maintained for 3 min in this embodiment), and then heated at a rate of 15 °C / min to 130 °C and maintained until the first detection spectrum is obtained (maintained for 6 min in this embodiment);

[0225] The injection temperature of the sulfur chemiluminescence detector 31 is 200 °C, the reaction temperature is 850 °C, the split ratio of the sulfur chemiluminescence detector 31 is 10:1, and the reaction gas flow rates of the sulfur chemiluminescence detector 31 are hydrogen (H2) 80 mL / min, nitrogen (N2) 40 mL / min, oxygen (O2) 10 mL / min, and ozone (O3) 25 mL / min.

[0226] Step S3: In the second chromatographic column analysis system 22, carrier gas is transported by the second carrier gas pipe 223. Under the drive of the carrier gas, the natural gas sample gas in the second metering tube 222 is separated successively using the first pre-separation column 224 and the first chromatographic analysis column 225. When the C5 in the natural gas sample gas - component leaves the first pre-separation column 224 and enters the first chromatographic analysis column 225, the carrier gas is switched to the outlet end of the first pre-separation column 224. The inlet end of the first pre-separation column 225 is connected to the hydrogen flame detector 32. Under the drive of the carrier gas, the C6 + hydrocarbon components in the first pre-separation column 224 are backflushed into the hydrogen flame detector 32 for detection. After the backflushing is completed, the carrier gas is switched to the inlet end of the first chromatographic analysis column 224. Under the drive of the carrier gas, the C3 - hydrocarbon components separated by the first chromatographic analysis column 225 enter the hydrogen flame detector 32 for detection in sequence, thereby obtaining a second detection spectrum. Specifically:

[0227] Switch the second injection valve 221 in the second chromatographic column analysis system 22 to the second gear. The carrier gas is introduced into the second chromatographic column analysis system 22 from the second carrier gas pipe 223 at a pressure of 500 kPa. The carrier gas successively enters the second metering tube 222 through the seventh valve port b7 and the eighth valve port b8, drives the natural gas sample gas in the second metering tube 222 to flow, and successively enters the first pre-separation column 224 through the first valve port b1 and the second valve port b2, where pre-separation is performed. Propane, isobutane, n-butane, neopentane, isopentane, and n-pentane are successively discharged from the first pre-separation column 224 and successively enter the first chromatographic analysis column 225 through the sixth valve port b6 and the fifth valve port b5 for further separation to increase the separation time difference between components. When the C5 - component leaves the first pre-separation column 224 and enters the first chromatographic analysis column 225, switch the second injection valve 221 in the second chromatographic column analysis system 22 to the first gear. The carrier gas is introduced at a pressure of 500 kPa from the second carrier gas pipe 223. The carrier gas successively enters the first pre-separation column 224 from the outlet end of the first pre-separation column 224 through the seventh valve port b7 and the sixth valve port b6, and the C6 in the first pre-separation column 224 +The hydrocarbon components above are blown out of the first pre-separation column 224, and after passing through the second valve port b2 and the third valve port b3, enter the hydrogen flame detector 32 for detection; after the hydrogen flame detector 32 detects the hexane combined peak, the flow direction of the carrier gas is adjusted; the carrier gas is introduced into the second carrier gas pipe 223 at a pressure of 500 kPa, and the carrier gas passes through the fourth valve port b4 and the fifth valve port b5 in sequence and then enters the first chromatographic analysis column 225. Driven by the carrier gas, propane, isobutane, n-butane, neopentane, isopentane, and n-pentane leave the first chromatographic analysis column 225 in sequence and enter the hydrogen flame detector 32 for detection, obtaining a second detection spectrum. Refer to Figure 8 ;

[0228] Among them, helium is selected as the carrier gas;

[0229] The first chromatographic analysis column 225 is maintained at 40 °C until the hexane combined peak is detected (maintained for 3 min in this embodiment), and then heated to 130 °C at a rate of 15 °C / min and maintained until the second detection spectrum is obtained (maintained for 6 min in this embodiment);

[0230] The temperature of the hydrogen flame detector 32 is 200 °C, and the flow rates of the reaction gases of the hydrogen flame detector 32 are 32 mL / min of hydrogen (H2), 200 mL / min of air, and 20 mL / min of make-up gas.

[0231] Step S4: In the third chromatographic column analysis system 23, the carrier gas is transported by the third carrier gas pipe 233, and the natural gas sample gas in the third quantitative tube 232 is separated by using the second pre-separation column 234 and the second chromatographic analysis column 235 in sequence under the drive of the carrier gas; when the oxygen, nitrogen, methane, and carbon monoxide components in the natural gas sample gas leave the second pre-separation column 234 and enter the second chromatographic analysis column 235, the carrier gas is transferred to the outlet end of the second pre-separation column 234, and the remaining components in the second pre-separation column 235 are blown out of the third chromatographic column analysis system 23 under the drive of the carrier gas; after the back-blowing is completed, the carrier gas is transferred to the inlet end of the second chromatographic analysis column 235, and the oxygen, nitrogen, methane, and carbon monoxide components separated by passing through the second chromatographic analysis column 235 enter the first thermal conductivity detector 33 in sequence under the drive of the carrier gas for detection; thus, a third detection spectrum is obtained; specifically:

[0232] Switch the third injection valve 231 in the third chromatographic column analysis system 23 to the second gear. The carrier gas is introduced into the third chromatographic column analysis system 23 from the third carrier gas pipe 233 at a pressure of 500 kPa. The carrier gas sequentially enters the third sampling tube 232 through the seventh valve port c7 and the eighth valve port c8, drives the natural gas sample gas in the third sampling tube 232 to flow, and then enters the second pre-separation column 234 after passing through the first valve port c1 and the second valve port c2. Pre-separation is carried out in the second pre-separation column 234. Oxygen, nitrogen, methane, and carbon monoxide are sequentially discharged from the second pre-separation column 234 and then enter the second chromatographic analysis column 235 after passing through the sixth valve port c6 and the fifth valve port c5 in sequence to further separate and increase the separation time difference between each component; after the oxygen, nitrogen, methane, and carbon monoxide components leave the second pre-separation column 234 and enter the second chromatographic analysis column 235, switch the third injection valve 231 in the third chromatographic column analysis system 23 to the first gear; the carrier gas is introduced from the third carrier gas pipe 233 at a pressure of 500 kPa. The carrier gas sequentially enters the second pre-separation column 234 from the outlet end of the second pre-separation column 234 through the seventh valve port c7 and the sixth valve port c6, and blows out the remaining components in the second pre-separation column 234 from the third chromatographic column analysis system 23; furthermore, adjust the flow direction of the carrier gas. The carrier gas is introduced from the third carrier gas pipe 233 at a pressure of 500 kPa. The carrier gas enters the second chromatographic analysis column 235 after passing through the fourth valve port c4 and the fifth valve port c5 in sequence. Driven by the carrier gas, oxygen, nitrogen, methane, and carbon monoxide sequentially leave the second chromatographic analysis column 235 and enter the first thermal conductivity detector 33 for detection to obtain a third detection spectrum. The third detection spectrum (the third detection spectrum and the fourth detection spectrum are combined into one detection spectrum) is shown in Figure 9 ;

[0233] Among them, helium is selected as the carrier gas;

[0234] The column temperature of the second chromatographic analysis column is 60 °C;

[0235] The temperature of the first thermal conductivity detector 33 is 150 °C, the working current of the first thermal conductivity detector 33 is 120 mA, and the polarity is the cathode.

[0236] Step S5: In the fourth chromatographic column analysis system 24, use the fourth carrier gas pipe 243 to transport the carrier gas. Under the drive of the carrier gas, the natural gas sample gas in the fourth metering tube 242 is separated successively by the third pre-separation column 244 and the third chromatographic analysis column 245; when the carbon dioxide and ethane components in the natural gas sample gas leave the third pre-separation column 244 and enter the third chromatographic analysis column 245, the carrier gas is transferred to the outlet end of the third pre-separation column 244, and the remaining components in the third pre-separation column 245 are blown out of the fourth chromatographic column analysis system 24 under the drive of the carrier gas; after the backflushing is completed, the carrier gas is transferred to the inlet end of the third chromatographic analysis column 245, and the carbon dioxide and ethane components separated by the third chromatographic analysis column 245 enter the first thermal conductivity detector 33 in sequence under the drive of the carrier gas for detection; thus, a fourth detection spectrum is obtained; specifically:

[0237] Switch the fourth injection valve 241 in the fourth chromatographic column analysis system 24 to the second gear. The carrier gas is introduced into the fourth chromatographic column analysis system 24 from the fourth carrier gas pipe 243 at a pressure of 350 kPa. The carrier gas successively passes through the seventh valve port d7 and the eighth valve port d8 and enters the fourth metering tube 242, driving the natural gas sample gas in the fourth metering tube 242 to flow, and successively passing through the first valve port d1 and the second valve port d2 and then entering the third pre-separation column 244 for pre-separation. Carbon dioxide and ethane are discharged from the third pre-separation column 244 successively and enter the third chromatographic analysis column 245 under the drive of the carrier gas for further separation to increase the separation time difference between the components; after the carbon dioxide and ethane components leave the third pre-separation column 244 and enter the third chromatographic analysis column 245, switch the fourth injection valve 241 in the third chromatographic column analysis system 23 to the first gear; the carrier gas is introduced from the fourth carrier gas pipe 243 at a pressure of 350 kPa. The carrier gas successively passes through the seventh valve port d7 and the sixth valve port d6 and enters the third pre-separation column 244 from the outlet end of the third pre-separation column 244, blowing out the remaining components in the third pre-separation column 244 from the third chromatographic column analysis system 23; then, adjust the flow direction of the carrier gas. The carrier gas is introduced from the fourth carrier gas pipe 243 at a pressure of 350 kPa. The carrier gas successively passes through the fourth valve port d4 and the fifth valve port d5 and then enters the third chromatographic analysis column 245. Under the drive of the carrier gas, carbon dioxide and ethane leave the third chromatographic analysis column 245 successively and enter the first thermal conductivity detector 33 for detection, obtaining a fourth detection spectrum. The fourth detection spectrum (the third detection spectrum and the fourth detection spectrum are combined into one detection spectrum) is shown in Figure 9 ;

[0238] Among them, helium is selected as the carrier gas;

[0239] The column temperature of the second chromatographic analysis column is 60 °C;

[0240] The temperature of the first thermal conductivity cell detector 33 is 150 °C, the working current of the first thermal conductivity cell detector 33 is 120 mA, and the polarity is the cathode.

[0241] Step S6: In the fifth chromatographic column analysis system 25, use the fifth carrier gas pipe 253 to transport the carrier gas. Driven by the carrier gas, the natural gas sample gas in the fifth quantitative tube 252 is separated successively using the fourth pre-separation column 254 and the fourth chromatographic analysis column 255; when the carbon dioxide and ethane components in the natural gas sample gas leave the fourth pre-separation column 254 and enter the fourth chromatographic analysis column 255, the carrier gas is transferred to the outlet end of the fourth pre-separation column 254, and the remaining components in the third pre-separation column 245 are backflushed out of the fifth chromatographic column analysis system 25 under the drive of the carrier gas; after the backflushing is completed, the carrier gas is transferred to the inlet end of the fourth chromatographic analysis column 255, and the carbon dioxide and ethane components separated by the fourth chromatographic analysis column 255 are successively introduced into the second thermal conductivity cell detector 34 for detection under the drive of the carrier gas; thus, a fifth detection chromatogram is obtained; specifically:

[0242] Switch the fifth injection valve 251 in the fifth chromatographic column analysis system 25 to the second gear. The carrier gas is introduced into the fifth chromatographic column analysis system 25 from the fifth carrier gas pipe 253 at a pressure of 250 kPa. The carrier gas successively enters the fifth quantitative tube 252 through the seventh valve port e7 and the eighth valve port e8, drives the natural gas sample gas in the fifth quantitative tube 252 to flow, and successively enters the fourth pre-separation column 254 after passing through the first valve port e1 and the second valve port e2. Pre-separation is performed in the fourth pre-separation column 254. Carbon dioxide and ethane are successively discharged from the fourth pre-separation column 254 and successively enter the fourth chromatographic analysis column 255 after passing through the sixth valve port e6 and the fifth valve port e5 for further separation to increase the separation time difference between each component; after the carbon dioxide and ethane components leave the fourth pre-separation column 254 and enter the fourth chromatographic analysis column 255, switch the fifth injection valve 251 in the third chromatographic column analysis system 23 to the first gear; the carrier gas is introduced at a pressure of 250 kPa from the fifth carrier gas pipe 253. The carrier gas successively enters the fourth pre-separation column 254 from the outlet end of the fourth pre-separation column 254 through the seventh valve port e7 and the sixth valve port e6, and blows out the remaining components in the fourth pre-separation column 254 from the third chromatographic column analysis system 23; then, adjust the flow direction of the carrier gas. The carrier gas is introduced at a pressure of 250 kPa from the fifth carrier gas pipe 253. The carrier gas successively enters the fourth chromatographic analysis column 255 after passing through the fourth valve port e4 and the fifth valve port e5. Under the drive of the carrier gas, carbon dioxide and ethane successively leave the fourth chromatographic analysis column 255 and enter the second thermal conductivity cell detector 34 for detection to obtain a fifth detection chromatogram. For the fifth detection chromatogram, see Figure 10 ;

[0243] Among them, nitrogen is selected as the carrier gas;

[0244] The column temperature of the second chromatographic column is 60 °C;

[0245] The temperature of the second thermal conductivity detector 34 is 150 °C, the working current of the second thermal conductivity detector 34 is 70 mA, and the polarity is anode.

[0246] Step S7: Determine the sulfide content in the natural gas sample gas based on the obtained first detection spectrum; specifically, based on the obtained first detection spectrum, use the sulfide content standard curve to determine the contents of carbonyl sulfide, hydrogen sulfide, methanethiol, ethanethiol, methyl sulfide, methyl ethyl sulfide, dimethyl disulfide, ethyl sulfide, carbon disulfide, n-butyl mercaptan, tert-butyl mercaptan, isopropyl mercaptan, and thiophene in the natural gas sample gas. The results are shown in Table 1;

[0247] Determine the hydrocarbon content above C3 in the natural gas sample gas based on the obtained second detection spectrum; specifically, based on the obtained second detection spectrum, use the hydrocarbon content standard curve above C3 to determine the contents of propane, isobutane, n-butane, neopentane, isopentane, n-pentane, and hydrocarbons above C6 in the natural gas sample gas. The results are shown in Table 2; + The above hydrocarbon component contents, and the results are shown in Table 2;

[0248] Determine the contents of oxygen, nitrogen, methane, and carbon monoxide in the natural gas sample gas based on the obtained third detection spectrum; specifically, based on the obtained third detection spectrum, use the oxygen, nitrogen, methane, and carbon monoxide content standard curves to determine the contents of oxygen, nitrogen, methane, and carbon monoxide in the natural gas sample gas. The results are shown in Table 3;

[0249] Determine the contents of carbon dioxide and ethane in the natural gas sample gas based on the obtained fourth detection spectrum; specifically, based on the obtained fourth detection spectrum, use the carbon dioxide and ethane content standard curves to determine the contents of carbon dioxide and ethane in the natural gas sample gas. The results are shown in Table 3;

[0250] Determine the contents of helium and hydrogen in the natural gas sample gas based on the obtained fifth detection spectrum; specifically, based on the obtained fifth detection spectrum, use the helium and hydrogen content standard curves to determine the contents of helium and hydrogen in the natural gas sample gas. The results are shown in Table 4.

[0251] Among them, the sulfide content standard curve is obtained by the following method: Seven bottles of standard substances of 4 sulfur compounds and 13 sulfur compounds at different concentration points are introduced into the instrument for analysis. Each bottle of standard substance is analyzed more than 11 times. Collect the effective 11-pin component peak area data. Plot the graph with the average value of the 11-pin component peak area and the corresponding content, and examine the relationship curve between the concentration and the response value of each component. The calibration curves of the 13 sulfur compounds are shown in Tables 5 - 17 below, Figures 11 - 23 ;

[0252] Obtain the standard curves of hydrocarbon substances with more than C3, the standard curves of oxygen, nitrogen, methane and carbon monoxide contents, and the standard curves of helium and hydrogen contents in the same way. The results are shown in Tables 18 - 30, Figures 24 - 36 as shown below;

[0253] Table 1

[0254] Content (ppm) S / N LOD (S / N = 3) (ppm) <![CDATA[H2S]]> 5.03 4167.315329 0.004107 COS 5.02 6224.611520 0.002739 Methyl mercaptan 5.01 6566.940805 0.002607 Ethyl mercaptan 5.02 5970.898393 0.002854 Dimethyl sulfide 4.98 6374.534079 0.002667 <![CDATA[CS2]]> 4.99 14033.098416 0.001214 Isopropyl mercaptan 4.97 5456.459935 0.003098 tert-Butyl mercaptan 4.98 4907.412677 0.003449 Methyl ethyl sulfide 5.09 6540.707642 0.002655 Thiophene 5.12 7051.172391 0.002478 Ethyl sulfide 4.98 6265.610865 0.002668 n-Butyl mercaptan 5.01 5403.188018 0.003151 Dimethyl disulfide 5.04 10803.035573 0.001581

[0255] Table 2

[0256]

[0257]

[0258] Table 3

[0259] Content (%) S / N LOD (S / N = 3) (%) <![CDATA[CO2]]> 0.199 3808.073 0.000172 <![CDATA[C2H6]]> 0.197 2833.088 0.000229 <![CDATA[O2]]> 0.2 4977.471 0.000133 <![CDATA[N2]]> 0.2 3799.549 0.000174 <![CDATA[CH4]]> 97.207 411381.3 0.000780 CO 0.199 1504.117 0.000437

[0260] Table 4

[0261] Content (%) S / N LOD (S / N = 3) (%) He 0.199 11306.401497 0.000058 <![CDATA[H2]]> 0.2 17661.056323 0.000037

[0262] Table 5 Corresponding Values Table of Hydrogen Sulfide Component Concentration and Response Value

[0263] Serial number Peak area <![CDATA[Content, mg / m 3 > 1 7755 0.995 2 23123 3.01 3 35894 4.93 4 61473 7.05 5 77139 10.1 6 113568 15 7 145374 20.1 8 175204 25.2 9 223374 29.9 10 257488 35 11 293867 40.1 12 318306 44.5 13 362401 49.9

[0264] Table 6 Corresponding Values Table of Carbonyl Sulfide Component Concentration and Response Value

[0265]

[0266]

[0267] Table 7 Corresponding Values Table of Methyl Mercaptan Component Concentration and Response Value

[0268] Serial number Peak area <![CDATA[Content, mg / m 3 > 1 8364 0.992 2 24219 3 3 38070 4.92 4 49528 7.03 5 81729 10.1 6 110957 15.1 7 144832 20.1 8 179477 25.3 9 228265 29.8 10 262857 34.9 11 300462 40 12 325956 44.4 13 365652 49.7

[0269] Table 8 Corresponding Values Table of Ethyl Mercaptan Component Concentration and Response Value

[0270]

[0271]

[0272] Table 9 Corresponding Values Table of Dimethyl Sulfide Component Concentration and Response Value

[0273] Serial number 1 2 3 4 Peak area 39105 81791 110268 137852 <![CDATA[Content, mg / m 3 > 5.1 10.2 15.2 20.2

[0274] Table 10 Corresponding Values Table of Carbon Disulfide Component Concentration and Response Value

[0275] Serial number 1 2 3 4 Peak area 40022 84178 113526 141749 <![CDATA[Content, mg / m 3 > 5.17 10.3 15.3 20.5

[0276] Table 11 Corresponding Values Table of Isopropyl Mercaptan Component Concentration and Response Value

[0277] Serial number 1 2 3 4 Peak area 38399 80736 108164 135258 <![CDATA[Content, mg / m 3 > 5.07 10.1 15 20.1

[0278] Table 12 Corresponding Values Table of tert-Butyl Mercaptan Component Concentration and Response Value

[0279] Serial number 1 2 3 4 Peak area 38543 80962 108250 135598 <![CDATA[Content, mg / m 3 > 5.05 10.1 15.0 20.0

[0280] Table 13 Corresponding Values Table of Methyl Ethyl Sulfide Component Concentration and Response Value

[0281] Serial number 1 2 3 4 Peak area 37895 79999 107262 134436 <![CDATA[Content, mg / m 3 > 5.14 10.3 15.3 20.3

[0282] Table 14 Corresponding Values Table of Thiophene Component Concentration and Response Value

[0283] Serial number 1 2 3 4 Peak area 38278 80734 108777 136348 <![CDATA[Content, mg / m 3 > 5.06 10.1 15.0 20.0

[0284] Table 15 Corresponding Values Table of Ethyl Sulfide Component Concentration and Response Value

[0285] Serial number 1 2 3 4 Peak area 38654 81228 108819 136410 <![CDATA[Content, mg / m 3 > 5.04 10.1 15.0 20.0

[0286] Table 16 Corresponding Values Table of n-Butyl Mercaptan Component Concentration and Response Value

[0287] Serial number 1 2 3 4 Peak area 36725 77902 104555 131298 <![CDATA[Content, mg / m 3 > 5.04 10.1 15.0 20.0

[0288] Table 17 Corresponding Values Table of Dimethyl Disulfide Component Concentration and Response Value

[0289] Serial number 1 2 3 4 Peak area 37989 79919 107123 134151 <![CDATA[Content, mg / m 3 > 4.99 10.0 15.0 20.0

[0290] Table 18 Corresponding Values Table of Carbon Dioxide Component Concentration and Response Value

[0291] Serial number 1 2 3 4 5 6 Peak area 276 2688 50784 90583 131274 183647 Reference value of standard substance, y, % 0.0105 0.105 1.93 3.46 5.02 7.01

[0292] Table 19 Corresponding Values Table of Ethane Component Concentration and Response Value

[0293] Serial number 1 2 3 4 5 6 Peak area 277 2688 52359 97512 138525 189990 Reference value of standard substance, y, % 0.0105 0.106 1.83 3.4 4.85 6.63

[0294] Table 20 Corresponding Values Table of Nitrogen Component Concentration and Response Value

[0295] Serial number 1 2 3 4 5 6 Peak area 867 5710 65424 122862 207039 288884 Reference value of standard substance, y, % 0.0281 0.189 1.73 3.49 5.32 7.39

[0296] Table 21 Corresponding Values Table of Helium Component Concentration and Response Value

[0297] Serial number 1 2 3 4 Peak area 1517 7540 41303 72947 <![CDATA[Content, mg / m 3 > 0.0105 0.088 0.513 0.93

[0298] Table 22 Corresponding Values Table of Hydrogen Component Concentration and Response Value

[0299] Serial number 1 2 3 4 Peak area 1424 12544 190478 370350 <![CDATA[Content, mg / m 3 > 0.0114 0.09 1.36 2.67

[0300] Table 23 Corresponding Values Table of Hexane Component Concentration and Response Value

[0301] Serial number 1 2 3 4 5 6 Peak area 162737 1181843 1834728 2267348 3199737 3292007 Reference value of standard substance, y, % 0.013 0.0923 0.131 0.201 0.262 0.282

[0302] Table 24 Corresponding Values Table of Propane Component Concentration and Response Value

[0303] Serial number 1 2 3 4 5 6 Peak area 74514 840546 6689402 12540797 18536241 25084340 Reference value of standard substance, y, % 0.0105 0.114 0.883 1.85 2.39 3.24

[0304] Table 25 Corresponding Values Table of Carbon Monoxide Component Concentration and Response Value

[0305] Serial number 1 2 3 4 5 6 Peak area 3242 8645 13585 22539 27093 120340 Reference value of standard substance, y, % 0.084 0.224 0.352 0.584 0.702 3.24

[0306] Table 26 Corresponding Values Table of Isobutane Component Concentration and Response Value

[0307] Serial number 1 2 3 4 5 6 Peak area 197855 1022004 3058375 4649287 7216474 9990056 Reference value of standard substance, y, % 0.0209 0.105 0.306 0.522 0.704 0.977

[0308] Table 27 Corresponding Values Table of n-Butane Component Concentration and Response Value

[0309] Serial number 1 2 3 4 5 6 Peak area 247785 1151669 2974204 4510332 7051530 9831076 Reference value of standard substance, y, % 0.0264 0.119 0.299 0.507 0.688 0.960

[0310] Table 28 Corresponding Values Table of Neopentane Component Concentration and Response Value

[0311] Serial number 1 2 3 4 5 6 Peak area 315140 1512452 2875956 3466614 5151799 6773936 Reference value of standard substance, y, % 0.0265 0.124 0.23 0.311 0.4 0.526

[0312] Table 29 Corresponding Values Table of Isopentane Component Concentration and Response Value

[0313] Serial number 1 2 3 4 5 6 Peak area 299733 1332670 2654538 3339374 4684940 6288516 Reference value of standard substance, y, % 0.0261 0.113 0.218 0.307 0.372 0.498

[0314] Table 30 Corresponding Values Table of n-Pentane Component Concentration and Response Value

[0315] Serial number 1 2 3 4 5 6 Peak area 303535 1270585 2616985 3370006 5092523 6586821 Reference value of standard substance, y, % 0.0264 0.107 0.213 0.31 0.401 0.52

[0316] Step S8: Based on the obtained contents of sulfide, hydrocarbons with C3 and above, oxygen, nitrogen, methane, and carbon monoxide, carbon dioxide and ethane, helium and hydrogen in the natural gas sample gas, determine the higher heating value, total sulfur content (calculated as sulfur, mg / m 3 ), hydrogen sulfide content (mg / m 3 ), and carbon dioxide content (mole percentage) of the natural gas.

[0317] In this analysis method, from Figures 7 - 10 it can be seen that the resolution of each target component is relatively high, LOD (S / N = 3) < 50 ppm; the resolution is greater than 1, among which i-C4H1, n-C4H 10The resolution can reach 4.45, the resolution of CH4 and CO can reach 5.245, and the resolution of H2S and COS can reach 2.701.

[0318] Specific embodiments are used in the present invention to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation on the present invention.

Claims

1. An analytical device for natural gas product quality indicators, wherein, The device includes a sampling component and first, second, third, fourth, and fifth chromatographic column analysis systems connected in parallel; the first chromatographic column analysis system is used to separate sulfides in natural gas; the second chromatographic column analysis system is used to separate hydrocarbons with more than C3 in natural gas; the third chromatographic column analysis system is used to separate oxygen, nitrogen, methane, and carbon monoxide in natural gas; the fourth chromatographic column analysis system is used to separate carbon dioxide and ethane in natural gas; the fifth chromatographic column analysis system is used to separate helium and hydrogen in natural gas; among them, each chromatographic column analysis system is provided with a metering tube, a carrier gas pipe, and a chromatographic column. The metering tube is used to store the natural gas sample gas, and the carrier gas pipe is used to transport the carrier gas to the chromatographic column analysis system to drive the natural gas sample gas in the metering tube to perform component separation in the chromatographic column; the sampling component is controllably connected to the metering tubes of the first, second, third, fourth, and fifth chromatographic column analysis systems, and is used to provide the natural gas sample gas to the metering tubes of the first, second, third, fourth, and fifth chromatographic column analysis systems; by connecting the sampling component to the metering tubes of the first, second, third, fourth, and fifth chromatographic column analysis systems, the metering tubes of the first, second, third, fourth, and fifth chromatographic column analysis systems are connected in series; among them, the sampling component includes a natural gas inlet pipe, a natural gas outlet pipe, and first, second, third, and fourth metering tube connecting pipes. The first, second, third, and fourth metering tube connecting pipes are respectively used to connect the metering tubes in series. The natural gas inlet pipe is connected to the inlet end of the series-connected metering tubes, and the natural gas outlet pipe is connected to the outlet end of the series-connected metering tubes; each chromatographic column analysis system is respectively connected to a corresponding detector; among them, the chromatographic column of the first chromatographic column analysis system includes a sulfur column, and the sulfur column can separate carbonyl sulfide, hydrogen sulfide, methanethiol, ethanethiol, methyl sulfide, methyl ethyl sulfide, dimethyl disulfide, ethyl sulfide, carbon disulfide, n-butyl mercaptan, tert-butyl mercaptan, isopropyl mercaptan, and thiophene; Among them, the chromatographic column of the second chromatographic column analysis system includes a first pre-separation column and a first chromatographic analysis column. The first pre-separation column can separate hydrocarbon components of C6 + from hydrocarbon components of C5 - . The first chromatographic analysis column can separate propane, isobutane, n-butane, neopentane, isopentane, and n-pentane. among them, the chromatographic column of the third chromatographic column analysis system includes a second pre-separation column and a second chromatographic analysis column. The second pre-separation column can separate oxygen, nitrogen, methane, and carbon monoxide from natural gas, and the second chromatographic analysis column can separate oxygen, nitrogen, methane, and carbon monoxide; among them, the chromatographic column of the fourth chromatographic column analysis system includes a third pre-separation column and a third chromatographic analysis column. The third pre-separation column can separate ethane and carbon dioxide from natural gas, and the third chromatographic analysis column can separate ethane and carbon dioxide; Among them, the chromatographic column of the fifth chromatographic column analysis system includes a fourth pre-separation column and a fourth chromatographic analysis column. The fourth pre-separation column can separate helium and hydrogen from natural gas, and the fourth chromatographic analysis column can separate helium and hydrogen.

2. The device according to claim 1, wherein, The first chromatographic column analysis system is connected to a sulfur chemiluminescence detector, the second chromatographic column analysis system is connected to a hydrogen flame detector, the third chromatographic column analysis system is connected to a thermal conductivity detector, the fourth chromatographic column analysis system is connected to a thermal conductivity detector, and / or the fifth chromatographic column analysis system is connected to a thermal conductivity detector.

3. The device according to claim 2, wherein, In the first chromatographic column analysis system, one end of the metering tube is connected to the carrier gas pipe through a controllable connection pipeline, and the other end is connected to the inlet end of the sulfur column through a controllable connection pipeline. The outlet end of the sulfur column is connected to the sulfur chemiluminescence detector through a controllable connection pipeline; and / or In the second chromatographic column analysis system, one end of the metering tube is connected to the carrier gas pipe through a controllable connection pipeline, and the other end is connected to the inlet end of the first pre-separation column through a controllable connection pipeline. The outlet end of the first pre-separation column is connected to the inlet end of the first chromatographic analysis column through a controllable connection pipeline. The carrier gas pipe is respectively connected to the outlet end of the first pre-separation column and the inlet end of the first chromatographic analysis column through controllable connection pipelines. The inlet end of the first pre-separation column and the outlet end of the first chromatographic analysis column are respectively connected to the hydrogen flame detector through controllable connection pipelines; and / or In the third chromatographic column analysis system, one end of the metering tube is connected to the carrier gas pipe through a controllable connection pipeline, and the other end is connected to the inlet end of the second pre-separation column through a controllable connection pipeline. The outlet end of the second pre-separation column is connected to the inlet end of the second chromatographic analysis column through a controllable connection pipeline. The carrier gas pipe is respectively connected to the outlet end of the second pre-separation column and the inlet end of the second chromatographic analysis column through controllable connection pipelines. The outlet end of the second chromatographic analysis column is connected to the thermal conductivity detector through a controllable connection pipeline; and / or In the fourth chromatographic column analysis system, one end of the metering tube is connected to the carrier gas pipe through a controllable connection pipeline, and the other end is connected to the inlet end of the third pre-separation column through a controllable connection pipeline. The outlet end of the third pre-separation column is connected to the inlet end of the third chromatographic analysis column through a controllable connection pipeline. The carrier gas pipe is respectively connected to the outlet end of the third pre-separation column and the inlet end of the third chromatographic analysis column through controllable connection pipelines. The outlet end of the third chromatographic analysis column is connected to the thermal conductivity detector through a controllable connection pipeline; and / or In the fifth chromatographic column analysis system, one end of the metering tube is communicated with the carrier gas pipe through a controllable on-off connecting pipeline, and the other end is communicated with the inlet end of the fourth pre-separation column through a controllable on-off connecting pipeline. The outlet end of the fourth pre-separation column is communicated with the inlet end of the fourth chromatographic analysis column through a controllable on-off connecting pipeline. The carrier gas pipe is respectively communicated with the outlet end of the fourth pre-separation column and the inlet end of the fourth chromatographic analysis column through controllable on-off connecting pipelines. The outlet end of the fourth chromatographic analysis column is communicated with a thermal conductivity detector through a controllable on-off connecting pipeline.

4. The device according to claim 1 or 3, wherein The sulfur column selects a DB-Sulfur SCD chromatographic column.

5. The apparatus according to claim 4, wherein The length of the DB-Sulfur SCD chromatographic column is 50m - 60m.

6. The device according to claim 1 or 3, wherein, The first pre-separation column is selected from one of an OV-1 pre-separation column and a DB-1 capillary column.

7. The device according to claim 6, wherein, The length of the OV-1 pre-separation column is 1.0 - 2.0m.

8. The device according to claim 6, wherein, The length of the DB-1 capillary column is 3.0 - 5.0m.

9. The device according to claim 1 or 3, wherein The first chromatographic analysis column is selected from one of an HP-Al / S chromatographic column, an HP-PLOT Al2O3 S capillary column, a PONA capillary column, and a plot Q capillary column.

10. The device according to claim 9, wherein, The length of the HP-Al / S chromatographic column is 30m - 50m.

11. The device according to claim 9, wherein, The length of the HP-PLOT Al2O3S capillary column is 25 m - 50m.

12. The device according to claim 9, wherein, The length of the PONA capillary column is 50 m - 100m.

13. The apparatus according to claim 9, wherein, The length of the plot Q capillary column is 25 m - 30m.

14. The device according to claim 1 or 3, wherein The second pre-separation column is selected from one of a Porapak N column, a Porapak Q column, and a Porapak QS column.

15. The apparatus according to claim 14, wherein, The length of the Porapak N column is 3m - 5m.

16. The device according to claim 1 or 3, wherein The second chromatographic analysis column is selected from one of a 13X molecular sieve column and a 5A molecular sieve column.

17. The apparatus according to claim 16, wherein, The second chromatographic analysis column selects an MS-13X molecular sieve column.

18. The device according to claim 17, wherein The length of the MS-13X molecular sieve column is 3.0m - 5.0m.

19. The device according to claim 1 or 3, wherein The third pre-separation column is selected from one of a Porapak N column, a Porapak Q column, and a Porapak QS column.

20. The apparatus according to claim 19, wherein, The length of the Porapak N column is 1m - 2m.

21. The device according to claim 1 or 3, wherein The third chromatographic analysis column is selected from one of a Porapak N column, a Porapak Q column, and a Porapak QS column.

22. The apparatus according to claim 21, wherein, The length of the Porapak N column is 2m - 3m.

23. The device according to claim 1 or 3, wherein, The fourth pre-separation column is selected from one of a Porapak N column, a Porapak Q column, and a Porapak QS column.

24. The device according to claim 23, wherein, The length of the Porapak N column is 1m - 2m.

25. The device according to claim 1 or 3, wherein, The fourth chromatographic analysis column is selected from one of a 13X molecular sieve column and a 5A molecular sieve column.

26. The device according to claim 25, wherein The fourth chromatographic analysis column selects an MS-5A molecular sieve column.

27. The apparatus according to claim 26, wherein, The length of the MS-5A molecular sieve column is 3.0m - 5.0m.

28. According to the device described in claim 3, wherein, The first chromatographic column analysis system includes a first injection valve, and the first injection valve is a multi-way valve including a first gear position and a second gear position; in the first chromatographic column analysis system, the first injection valve is respectively connected to both ends of a quantitative tube, a carrier gas tube, and a chromatographic column, and the on-off of the connecting pipelines between various components in the first chromatographic column analysis system and the on-off of the connecting pipeline between the injection assembly and the first chromatographic column analysis system are controlled by the first injection valve; When the first injection valve is switched to the first gear position, the gas in the injection assembly can be directly discharged from the first chromatographic column analysis system after passing through the quantitative tube; when the first injection valve is switched to the second gear position, the gas in the carrier gas tube of the first chromatographic column analysis system can flow through the quantitative tube of the first chromatographic column analysis system into the chromatographic column of the first chromatographic column analysis system.

29. The apparatus according to claim 28, wherein The first injection valve is a six-way valve including a first gear position and a second gear position. The six-way valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, and a sixth valve port in a clockwise direction; when the six-way valve is in the first gear position, the sixth valve port is connected to the first valve port, the second valve port is connected to the third valve port, and the fourth valve port is connected to the fifth valve port; when the six-way valve is in the second gear position, the first valve port is connected to the second valve port, the third valve port is connected to the fourth valve port, and the fifth valve port is connected to the sixth valve port; The sixth valve port and the fifth valve port of the first injection valve are respectively connected to the injection assembly. One end of the quantitative tube of the first chromatographic column analysis system is connected to the first valve port of the first injection valve, and the other end is connected to the fourth valve port of the first injection valve. The carrier gas tube of the first chromatographic column analysis system is connected to the second valve port of the first injection valve, and the sulfur column is connected to the third valve port of the first injection valve.

30. The apparatus according to claim 3, wherein The second chromatographic column analysis system includes a second injection valve, and the second injection valve is a multi-way valve including a first gear position and a second gear position; in the second chromatographic column analysis system, the second injection valve is respectively connected to both ends of a quantitative tube, a carrier gas tube, both ends of a first pre-separation column, the inlet end of a first chromatographic analysis column, and a hydrogen flame detector, and the on-off of the connecting pipelines between various components in the second chromatographic column analysis system and the on-off of the connecting pipeline between the injection assembly and the second chromatographic column analysis system are controlled by the second injection valve; When the second injection valve is switched to the first gear, the gas in the injection assembly can be directly discharged from the second chromatographic column analysis system after passing through the metering tube. The gas in the carrier gas pipe of the second chromatographic column analysis system can enter from the outlet end of the first pre-separation column and flow out from the inlet end of the first pre-separation column and then flow into the hydrogen flame detector. The gas in the carrier gas pipe of the second chromatographic column analysis system can enter the first chromatographic analysis column from the inlet end of the first chromatographic analysis column. When the second injection valve is switched to the second gear, the gas in the carrier gas pipe of the second chromatographic column analysis system can flow through the metering tube of the second chromatographic column analysis system to the first pre-separation column, enter from the inlet end of the first pre-separation column and flow out from the outlet end of the first pre-separation column, and then enter the first chromatographic analysis column from the inlet end of the first chromatographic analysis column.

31. The device according to claim 30, wherein the second injection valve is a ten-way valve including a first gear and a second gear. The second injection valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port, and a tenth valve port in a clockwise direction. When the second injection valve is in the first gear, the tenth valve port is connected to the first valve port, the second valve port is connected to the third valve port, the fourth valve port is connected to the fifth valve port, the sixth valve port is connected to the seventh valve port, and the eighth valve port is connected to the ninth valve port. When the second injection valve is in the second gear, the first valve port is connected to the second valve port, the third valve port is connected to the fourth valve port, the fifth valve port is connected to the sixth valve port, the seventh valve port is connected to the eighth valve port, and the ninth valve port is connected to the tenth valve port. The tenth valve port and the ninth valve port of the second injection valve are respectively connected to the injection assembly. One end of the metering tube of the second chromatographic column analysis system is connected to the first valve port of the second injection valve, and the other end is connected to the eighth valve port of the second injection valve. The carrier gas pipe of the second chromatographic column analysis system is respectively connected to the seventh valve port of the second injection valve and the fourth valve port of the second injection valve. The inlet end of the first pre-separation column is connected to the second valve port of the second injection valve, and the outlet end is connected to the sixth valve port of the second injection valve. The inlet end of the first chromatographic analysis column is connected to the fifth valve port of the second injection valve. The third valve port of the second injection valve is connected to the hydrogen flame detector.

32. The device according to claim 3, wherein the third chromatographic column analysis system includes a third injection valve, and the third injection valve is a multi-way valve including a first gear and a second gear. In the third chromatographic column analysis system, the third injection valve is respectively connected to both ends of the metering tube, the carrier gas pipe, both ends of the second pre-separation column, and the inlet end of the second chromatographic analysis column. The on-off of the connecting pipes between the components in the third chromatographic column analysis system and the on-off of the connecting pipes between the injection assembly and the third chromatographic column analysis system are controlled by the third injection valve. When the third injection valve is switched to the first gear position, the gas in the injection assembly can be directly discharged from the third chromatographic column analysis system after passing through the metering tube. The gas in the carrier gas pipe of the third chromatographic column analysis system can enter from the outlet end of the second pre-separation column and flow out from the inlet end of the second pre-separation column and then be discharged from the analysis system. The gas in the carrier gas pipe of the third chromatographic column analysis system can enter from the inlet end of the second chromatographic analysis column and enter the second chromatographic analysis column. When the third injection valve is switched to the second gear position, the gas in the carrier gas pipe of the third chromatographic column analysis system can flow through the metering tube of the third chromatographic column analysis system to the second pre-separation column, enter from the inlet end of the second pre-separation column and flow out from the outlet end of the second pre-separation column, and then enter the second chromatographic analysis column from the inlet end of the second chromatographic analysis column.

33. The apparatus according to claim 32, wherein the third injection valve is a ten-way valve including a first gear position and a second gear position. The third injection valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port and a tenth valve port in a clockwise direction. When the third injection valve is in the first gear position, the tenth valve port is communicated with the first valve port, the second valve port is communicated with the third valve port, the fourth valve port is communicated with the fifth valve port, the sixth valve port is communicated with the seventh valve port, and the eighth valve port is communicated with the ninth valve port. When the third injection valve is in the second gear position, the first valve port is communicated with the second valve port, the third valve port is communicated with the fourth valve port, the fifth valve port is communicated with the sixth valve port, the seventh valve port is communicated with the eighth valve port, and the ninth valve port is communicated with the tenth valve port. The tenth valve port and the ninth valve port of the third injection valve are respectively communicated with the injection assembly. One end of the metering tube of the third chromatographic column analysis system is communicated with the first valve port of the third injection valve, and the other end is communicated with the eighth valve port of the third injection valve. The carrier gas pipe of the third chromatographic column analysis system is respectively communicated with the seventh valve port of the third injection valve and the fourth valve port of the third injection valve. The inlet end of the second pre-separation column is communicated with the second valve port of the third injection valve, and the outlet end is communicated with the sixth valve port of the third injection valve. The inlet end of the second chromatographic analysis column is communicated with the fifth valve port of the third injection valve.

34. The apparatus according to claim 3, wherein the fourth chromatographic column analysis system includes a fourth injection valve, and the fourth injection valve is a multi-way valve including a first gear position and a second gear position. In the fourth chromatographic column analysis system, the fourth injection valve is respectively communicated with both ends of the metering tube, communicated with the carrier gas pipe, communicated with both ends of the third pre-separation column, and communicated with the inlet end of the third chromatographic analysis column. The on-off of the connecting pipelines between the various components in the fourth chromatographic column analysis system and the on-off of the connecting pipelines between the injection assembly and the fourth chromatographic column analysis system are controlled by the fourth injection valve. When the fourth sampling valve is switched to the first gear, the gas in the sampling assembly can be directly discharged from the fourth chromatographic column analysis system after passing through the metering tube. The gas in the carrier gas pipe of the fourth chromatographic column analysis system can enter from the outlet end of the third pre-separation column and flow out from the inlet end of the third pre-separation column, and then be discharged from the three-analysis system. The gas in the carrier gas pipe of the fourth chromatographic column analysis system can enter from the inlet end of the third chromatographic analysis column and enter the third chromatographic analysis column. When the fourth sampling valve is switched to the second gear, the gas in the carrier gas pipe of the fourth chromatographic column analysis system can flow through the metering tube of the fourth chromatographic column analysis system to the third pre-separation column, enter from the inlet end of the third pre-separation column and flow out from the outlet end of the third pre-separation column, and then enter the third chromatographic analysis column from the inlet end of the third chromatographic analysis column.

35. The device according to claim 34, wherein the fourth sampling valve is a ten-way valve including a first gear and a second gear. The fourth sampling valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port, and a tenth valve port in a clockwise direction. When the fourth sampling valve is in the first gear, the tenth valve port is communicated with the first valve port, the second valve port is communicated with the third valve port, the fourth valve port is communicated with the fifth valve port, the sixth valve port is communicated with the seventh valve port, and the eighth valve port is communicated with the ninth valve port. When the fourth sampling valve is in the second gear, the first valve port is communicated with the second valve port, the third valve port is communicated with the fourth valve port, the fifth valve port is communicated with the sixth valve port, the seventh valve port is communicated with the eighth valve port, and the ninth valve port is communicated with the tenth valve port. The tenth valve port and the ninth valve port of the fourth sampling valve are respectively communicated with the sampling assembly. One end of the metering tube of the fourth chromatographic column analysis system is communicated with the first valve port of the fourth sampling valve, and the other end is communicated with the eighth valve port of the fourth sampling valve. The carrier gas pipe of the fourth chromatographic column analysis system is respectively communicated with the seventh valve port of the fourth sampling valve and the fourth valve port of the fourth sampling valve. The inlet end of the third pre-separation column is communicated with the second valve port of the fourth sampling valve, and the outlet end is communicated with the sixth valve port of the fourth sampling valve. The inlet end of the third chromatographic analysis column is communicated with the fifth valve port of the fourth sampling valve.

36. The device according to claim 3, wherein the fifth chromatographic column analysis system includes a fifth sampling valve, and the fifth sampling valve is a multi-way valve including a first gear and a second gear. In the fifth chromatographic column analysis system, the fifth sampling valve is respectively communicated with both ends of the metering tube, the carrier gas pipe, both ends of the fourth pre-separation column, and the inlet end of the fourth chromatographic analysis column. The on-off of the connecting pipelines between the components in the fifth chromatographic column analysis system and the on-off of the connecting pipelines between the sampling assembly and the fifth chromatographic column analysis system are controlled by the fifth sampling valve. When the fifth injection valve is switched to the first gear, the gas in the injection assembly can be directly discharged from the fifth chromatographic column analysis system after passing through the metering tube, the gas in the carrier gas pipe of the fifth chromatographic column analysis system can enter from the outlet end of the fourth pre-separation column and flow out from the inlet end of the fourth pre-separation column and then be discharged from the three analysis systems, and the gas in the carrier gas pipe of the fifth chromatographic column analysis system can enter the fourth chromatographic analysis column from the inlet end of the fourth chromatographic analysis column; when the fifth injection valve is switched to the second gear, the gas in the carrier gas pipe of the fifth chromatographic column analysis system can flow through the metering tube of the fifth chromatographic column analysis system to the fourth pre-separation column, enter from the inlet end of the fourth pre-separation column and flow out from the outlet end of the fourth pre-separation column, and then enter the fourth chromatographic analysis column from the inlet end of the fourth chromatographic analysis column.

37. The apparatus according to claim 36, wherein the fifth injection valve is a ten-way valve including a first gear and a second gear. The fifth injection valve is provided with a first valve port, a second valve port, a third valve port, a fourth valve port, a fifth valve port, a sixth valve port, a seventh valve port, an eighth valve port, a ninth valve port and a tenth valve port in a clockwise direction; when the fifth injection valve is in the first gear, the tenth valve port is communicated with the first valve port, the second valve port is communicated with the third valve port, the fourth valve port is communicated with the fifth valve port, the sixth valve port is communicated with the seventh valve port, and the eighth valve port is communicated with the ninth valve port; when the fifth injection valve is in the second gear, the first valve port is communicated with the second valve port, the third valve port is communicated with the fourth valve port, the fifth valve port is communicated with the sixth valve port, the seventh valve port is communicated with the eighth valve port, and the ninth valve port is communicated with the tenth valve port; the tenth valve port and the ninth valve port of the fifth injection valve are respectively communicated with the injection assembly. One end of the metering tube of the fifth chromatographic column analysis system is communicated with the first valve port of the fifth injection valve, and the other end is communicated with the eighth valve port of the fifth injection valve. The carrier gas pipe of the fifth chromatographic column analysis system is respectively communicated with the seventh valve port of the fifth injection valve and the fourth valve port of the fifth injection valve. The inlet end of the fourth pre-separation column is communicated with the second valve port of the fifth injection valve, and the outlet end is communicated with the sixth valve port of the fifth injection valve. The inlet end of the fourth chromatographic analysis column is communicated with the fifth valve port of the fifth injection valve.

38. The apparatus according to claim 3, wherein The apparatus further includes a programmed temperature rising device, and the sulfur column of the first chromatographic column analysis system and / or the first chromatographic analysis column of the second chromatographic column analysis system are arranged in the programmed temperature rising device.

39. The apparatus according to claim 3, wherein The apparatus further includes a constant temperature device, and the second chromatographic analysis column of the third chromatographic column analysis system, the third chromatographic analysis column of the fourth chromatographic column analysis system, and / or the fourth chromatographic analysis column of the fifth chromatographic column analysis system are arranged in the constant temperature device.

40. A method for analyzing the quality index of a natural gas product, which is carried out by using the natural gas product quality index analysis equipment described in any one of claims 1-39, wherein, The method includes: injecting samples into the metering tubes in the first chromatographic column analysis system, the second chromatographic column analysis system, the third chromatographic column analysis system, the fourth chromatographic column analysis system and the fifth chromatographic column analysis system to fill each metering tube with natural gas sample gas; In the first chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the sampling loop is separated for sulfides using a chromatographic column. The separated components are transported to a detector for detection to obtain a first detection spectrum. Based on the obtained first detection spectrum, the sulfide content in the natural gas sample gas is determined; In the second chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the sampling loop is separated for hydrocarbons with more than C3 using a chromatographic column. The separated components are transported to a detector for detection to obtain a second detection spectrum. Based on the obtained second detection spectrum, the content of hydrocarbons with more than C3 in the natural gas sample gas is determined; In the third chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the sampling loop is separated for oxygen, nitrogen, methane, and carbon monoxide using a chromatographic column. The separated components are transported to a detector for detection to obtain a third detection spectrum. Based on the obtained third detection spectrum, the contents of oxygen, nitrogen, methane, and carbon monoxide in the natural gas sample gas are determined; In the fourth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the sampling loop is separated for carbon dioxide and ethane using a chromatographic column. The separated components are transported to a detector for detection to obtain a fourth detection spectrum. Based on the obtained fourth detection spectrum, the contents of carbon dioxide and ethane in the natural gas sample gas are determined; In the fifth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the sampling loop is separated for helium and hydrogen using a chromatographic column. The separated components are transported to a detector for detection to obtain a fifth detection spectrum. Based on the obtained fifth detection spectrum, the contents of helium and hydrogen in the natural gas sample gas are determined; Based on the sulfide content, the content of hydrocarbons with more than C3, the contents of oxygen, nitrogen, methane, and carbon monoxide, the contents of carbon dioxide and ethane, and the contents of helium and hydrogen in the obtained natural gas sample gas, the higher heating value, total sulfur content, hydrogen sulfide content, and / or carbon dioxide content of the natural gas are determined.

41. The method according to claim 40, wherein The step of, in the first chromatographic column analysis system, transporting a carrier gas through a carrier gas pipe, and under the drive of the carrier gas, separating sulfides from the natural gas sample gas in the sampling loop using a chromatographic column, transporting the separated components to a detector for detection to obtain a first detection spectrum includes: In the first chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the sampling loop is transported to a sulfur column for sulfide separation. The separated components are transported to a sulfur chemiluminescence detector to detect the sulfides in the natural gas sample gas, obtaining a first detection spectrum.

42. The method according to claim 41, wherein, The sulfur column is maintained at 30 - 50 °C until carbonyl sulfide leaves the sulfur column, and then is heated to 130 °C at a rate of 10 - 20 °C / min and maintained.

43. The method according to claim 40, wherein, In the second chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the sampling loop is separated for hydrocarbons with more than C3 using a chromatographic column. The separated components are transported to a detector for detection. The steps for obtaining the second detection chromatogram include: In the second chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the quantitative tube is separated successively using a first pre-separation column and a first chromatographic analysis column; when the C5 - component in the natural gas sample gas leaves the first pre-separation column and enters the first chromatographic analysis column, the carrier gas is transferred to the outlet end of the first pre-separation column, and the inlet end of the first pre-separation column is connected to a hydrogen flame detector. Under the drive of the carrier gas, the C6 + hydrocarbon components in the first pre-separation column are backflushed into the hydrogen flame detector for detection; after the backflushing is completed, the carrier gas is transferred to the inlet end of the first chromatographic analysis column. Under the drive of the carrier gas, the separated C3 hydrocarbon components that have passed through the first chromatographic analysis column enter the hydrogen flame detector for detection in sequence; thus, a second detection chromatogram is obtained.

44. The method according to claim 43, wherein, The first chromatographic column is maintained at 30 - 50 °C until the peaks of hydrocarbon components with C6 ＋ or above are detected by the hydrogen flame detector, and then the temperature is raised to 130 °C at a rate of 10 - 20 °C / min and maintained.

45. The method according to claim 40, wherein, In the third chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the sampling loop is separated for oxygen, nitrogen, methane, and carbon monoxide using a chromatographic column. The separated components are transported to a detector for detection. The steps for obtaining the third detection chromatogram include: In the third chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the sampling loop is sequentially separated using a second pre-separation column and a second chromatographic analysis column. When the oxygen, nitrogen, methane, and carbon monoxide components in the natural gas sample gas leave the second pre-separation column and enter the second chromatographic analysis column, the carrier gas is transferred to the outlet end of the second pre-separation column. Driven by the carrier gas, the remaining components in the second pre-separation column are blown out of the third chromatographic column analysis system. After the backflush is completed, the carrier gas is transferred to the inlet end of the second chromatographic analysis column. Driven by the carrier gas, the oxygen, nitrogen, methane, and carbon monoxide components separated by the second chromatographic analysis column sequentially enter a thermal conductivity detector for detection, thereby obtaining the third detection chromatogram.

46. The method according to claim 45, wherein, The column temperature of the second chromatographic analysis column is 50 - 70 °C.

47. The method according to claim 40, wherein In the fourth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the sampling loop is separated for carbon dioxide and ethane using a chromatographic column. The separated components are transported to a detector for detection. The steps for obtaining the fourth detection chromatogram include: In the fourth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the sampling loop is sequentially separated using a third pre-separation column and a third chromatographic analysis column. When the carbon dioxide and ethane components in the natural gas sample gas leave the third pre-separation column and enter the third chromatographic analysis column, the carrier gas is transferred to the outlet end of the third pre-separation column. Driven by the carrier gas, the remaining components in the third pre-separation column are blown out of the fourth chromatographic column analysis system. After the backflush is completed, the carrier gas is transferred to the inlet end of the third chromatographic analysis column. Driven by the carrier gas, the carbon dioxide and ethane components separated by the third chromatographic analysis column sequentially enter a thermal conductivity detector for detection, thereby obtaining the fourth detection chromatogram.

48. The method according to claim 47, wherein, The column temperature of the third chromatographic analysis column is 50 - 70 °C.

49. The method according to claim 40, wherein, In the fifth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Driven by the carrier gas, the natural gas sample gas in the sampling loop is separated for helium and hydrogen using a chromatographic column. The separated components are transported to a detector for detection. The steps for obtaining the fifth detection chromatogram include: In the fifth chromatographic column analysis system, a carrier gas is transported through a carrier gas pipe. Under the drive of the carrier gas, the natural gas sample gas in the metering tube is separated successively using a fourth pre-separation column and a fourth chromatographic analysis column. After the helium and hydrogen components in the natural gas sample gas leave the fourth pre-separation column and enter the fourth chromatographic analysis column, the carrier gas is transferred to the outlet end of the fourth pre-separation column. Under the drive of the carrier gas, the remaining components in the fourth pre-separation column are blown out of the fifth chromatographic column analysis system. After the backflush is completed, the carrier gas is transferred to the inlet end of the fourth chromatographic analysis column. Under the drive of the carrier gas, the helium and hydrogen components separated by the fourth chromatographic analysis column enter the thermal conductivity detector in sequence for detection, thereby obtaining a fifth detection spectrum.

50. The method according to claim 49, wherein, The column temperature of the fourth chromatographic analysis column is 50-70 °C.

51. Application of the natural gas product quality index analysis device according to any one of claims 1-39 in the analysis of natural gas products.

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