A helium ion gas chromatograph suitable for SF6 decomposition product detection

Abstract

The application discloses a helium ion gas chromatograph suitable for SF6 decomposition product detection, wherein sample gas in a quantitative ring is introduced into a rear-stage adsorption column through carrier gas, the adsorption column contains sufficient kdhf-0 type molecular sieve, after the sample gas and the carrier gas are left in the adsorption column for a set time, SO2 gas is completely adsorbed, and then the gas containing only helium and SF6 gas after adsorption is blown to a rear-stage chromatographic column for separation through the carrier gas; after a set time, a heating rod in the adsorption column is started to heat the molecular sieve to 100 DEG C for desorption, the desorbed SO2 gas is introduced into a small gas storage tank through the carrier gas, after a set time, a valve is controlled to make the carrier gas stop entering the adsorption column, a vacuum pump is started to exhaust all residual gas in the adsorption column into the gas storage tank, then the vacuum pump is stopped, the carrier gas is controlled to flow through the adsorption column again, the gas in the gas storage tank is pushed into the rear-stage chromatographic column, and the SO2 gas in the gas is introduced into a PDHID detector, so that the ultra-low concentration SO2 gas concentration is accurately detected without SF6 gas interference.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas detection, in particular to a helium ion gas chromatograph suitable for SF6 decomposition product detection. BACKGROUND

[0002] Sulfur hexafluoride (SF6) is the most ideal insulating and arc-extinguishing medium among all substances in nature and artificially synthesized. Although its global warming potential (GWP) is 23900 times that of CO2, it is still widely used in power systems. SF6 gas will generate trace amounts of toxic and corrosive gases such as SO2, SOF2 (fluorinated sulfuryl), H2S, CO, etc. under the action of latent faults such as discharge or overheating, which will damage the insulation materials and further trigger more serious faults. In power systems, latent faults and fault types are often judged by detecting decomposition products, and then corresponding defense measures are selected. SO2, as the most important characteristic decomposition product, its concentration is generally used as the primary basis for judging latent faults by field operation and maintenance personnel.

[0003] Currently, SF6 gas decomposition product detection is mainly divided into field detection and laboratory detection, and the accuracy and sensitivity of laboratory detection are significantly higher than those of field detection. In the early stage of latent faults, the concentration of SO2 may be only a few hundred ppb (volume per billionth) to several ppm (volume per millionth), and it is difficult for field detection instruments to detect such low concentration of SO2. Therefore, for the detection of very low concentration of SO2, laboratory detection instruments, i.e. gas chromatographs, are generally used. Gas chromatographs can be divided into thermal conductivity method, sulfur chemiluminescence method, helium ion method, etc. according to different detectors, among which helium ion gas chromatographs are widely used in ultra-low concentration gas impurity analysis due to their extremely high detection sensitivity. The basic detection principle of helium ion gas chromatograph is that the gas flowing out in sequence after being separated by the chromatographic column is introduced into the PDHID detector through the valve technology. The PDHID generates an electric arc by discharge to electrolyze helium into high-energy metastable helium ions, which ionizes the gas components to be detected to realize the detection of impurity gas concentration. However, when detecting the SO2 gas of SF6 gas decomposition products, the concentration of SF6 in the sample gas is generally more than 99%, and it is difficult for the valve to completely separate SF6 and SO2 gas flowing out in sequence after chromatographic column separation. Once a small amount of SF6 gas enters the PDHID detector together with SO2 gas, the electric arc generated by the discharge of PDHID will be quickly extinguished by SF6 gas with excellent arc-extinguishing ability, and helium cannot be fully ionized into high-energy metastable helium ions, thereby affecting the ionization result of SO2 gas and leading to the decrease of detection sensitivity and accuracy.

[0004] Therefore, it is urgent to study corresponding technology to solve the influence of SF6 gas on the helium ion gas chromatography PDHID detector in the prior art, and to improve the detection sensitivity and accuracy when analyzing the concentration of SF6 gas decomposition product SO2 gas. SUMMARY

[0005] The technical problem to be solved by the present application is how to solve the problem that when SF6 gas decomposition product SO2 is detected by a helium ion gas chromatograph, SF6 gas has an arc extinguishing effect on the discharge arc of the PDHID detector, affects the ionization of helium, and reduces the detection sensitivity and accuracy.

[0006] The present application solves the above technical problems by the following technical means:

[0007] A helium ion gas chromatograph suitable for SF6 decomposition product detection, comprising a six-way valve, a quantitative ring, an adsorption column, a vacuum pump, a gas storage tank, a chromatographic column, a PDHID detector, and first to eleventh electromagnetic valves.

[0008] The carrier gas inlet is in communication with the carrier gas inlet of the six-way valve, the carrier gas outlet of the six-way valve is in communication with the inlet of the adsorption column, the outlet of the adsorption column is in communication with the inlet of the chromatographic column, the outlet of the chromatographic column is in communication with the inlet of the PDHID detector, and the carrier gas inlet is in communication with the inlet of the PDHID detector.

[0009] The first electromagnetic valve is connected in series between the carrier gas inlet and the carrier gas inlet of the six-way valve, the tenth electromagnetic valve is connected in series between the carrier gas inlet and the PDHID detector, the third electromagnetic valve, the seventh electromagnetic valve, and the ninth electromagnetic valve are connected in series between the adsorption column and the chromatographic column, the eighth electromagnetic valve is connected in series between the upstream of the ninth electromagnetic valve and the upstream of the tenth electromagnetic valve, the second electromagnetic valve, the vacuum pump, the fifth electromagnetic valve, the gas storage tank, and the sixth electromagnetic valve are connected in series between the outlet of the adsorption column and the upstream of the ninth electromagnetic valve, and the fourth electromagnetic valve is connected in series between the downstream of the third electromagnetic valve and the outlet of the vacuum pump. The present application introduces the sample gas in the quantitative ring into the rear adsorption column through the carrier gas, the adsorption column contains sufficient kdhf-0 type molecular sieve, the sample gas and the carrier gas are left to stand in the adsorption column for a set time, the SO2 gas is completely adsorbed, the gas containing only helium and SF6 gas after adsorption is swept to the rear chromatographic column for separation, the heating rod in the adsorption column is started after a set time, the molecular sieve is heated to 100 DEG C for desorption, the desorbed SO2 gas is introduced into the small gas storage tank through the carrier gas, the carrier gas is temporarily stopped from entering the adsorption column by controlling the valve after a set time, the residual gas in the adsorption column is completely pumped into the gas storage tank by starting the vacuum pump, then the vacuum pump is stopped, the carrier gas flows through the adsorption column again by controlling the valve, the gas in the gas storage tank is pushed into the rear chromatographic column, and the SO2 gas in the gas enters the PDHID detector without the interference of SF6 gas, so that the ultra-low concentration of SO2 gas concentration is accurately detected.

[0010] The application adopts adsorbent to adsorb and desorb SO2 gas, so as to completely separate SO2 and SF6, SO2 enters the chromatographic column after SF6, so as to avoid the existence of a small amount of SF6 gas when the PDHID detector detects SO2, and reduce the detection sensitivity and accuracy.

[0011] Further, the exhaust pipeline of the PDHID detector is connected with a check valve.

[0012] Further, the exhaust pipeline of the vacuum pump is provided with an eleventh electromagnetic valve.

[0013] Further, the adsorption column comprises a molecular sieve and a heating rod, and the heating rod heats the molecular sieve.

[0014] Further, the detection method comprises the following steps:

[0015] Step. Vacuumizing;

[0016] Step. Purging;

[0017] Step. After the purging is completed, the six-way valve is connected with the sample gas inlet and the quantitative ring inlet through the switch valve, the sample gas enters the quantitative ring, after a certain volume of gas is collected, the six-way valve is sequentially connected with the carrier gas inlet, the quantitative ring inlet, the quantitative ring outlet and the carrier gas outlet through the switch valve, the carrier gas carries the sample gas in the quantitative ring into the post-stage adsorption column;

[0018] Step. After the carrier gas containing the sample gas enters the adsorption column, all the electromagnetic valves are closed, the gas is stored in the adsorption column, and after a certain time length is set, the third electromagnetic valve, the seventh electromagnetic valve and the ninth electromagnetic valve are opened, only the gas containing helium and SF6 enters the post-stage chromatographic column, and after being separated by the chromatographic column, enters the post-stage PDHID detector, and is discharged to the outside from the detection gas outlet after being detected and analyzed.

[0019] Step. After the third solenoid valve is opened for a set time, the SF6 gas in the adsorption column has been completely pushed out by the carrier gas and enters the chromatographic column, at this time the third solenoid valve and the seventh solenoid valve are closed, the six-way valve is disconnected by the switch valve to disconnect the carrier gas inlet and the quantitative ring, and the carrier gas enters the carrier gas inlet and is directly discharged; at this time the eighth solenoid valve is opened, and the carrier gas continues to enter the chromatographic column; then, after the heating rod in the adsorption column is started to heat to a set temperature, the second solenoid valve and the fifth solenoid valve are opened, the vacuum pump is started, and the desorbed SO2 is pumped into the gas storage tank; after a set time of vacuum pumping, all the SO2 gas in the adsorption column has been pumped into the gas storage tank, at this time the vacuum pump is closed, the second solenoid valve, the seventh solenoid valve and the eighth solenoid valve are closed, and the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve and the sixth solenoid valve are opened, the six-way valve is connected by the switch valve to connect the carrier gas inlet and the carrier gas outlet, the carrier gas continues to push the SO2 gas in the gas storage tank into the later-stage chromatographic column, and then passes through the PDHID detector, is discharged to the outside world from the detection gas outlet after detection and analysis, and after the SO2 detection result appears, all the solenoid valves are closed, the gas inlet is stopped, and the detection process is ended.

[0020] Further, the step of vacuum pumping specifically comprises the following steps: the vacuum pump is opened, the second solenoid valve, the third solenoid valve, the sixth solenoid valve, the seventh solenoid valve and the eleventh solenoid valve are opened, and other solenoid valves are closed; vacuum pumping is performed until a set value is reached; then the vacuum pump is closed, and all the solenoid valves are closed.

[0021] Further, the step of purging specifically comprises the following steps: the carrier gas enters from the carrier gas inlet, the first solenoid valve and the tenth solenoid valve are opened, one-way flows to the carrier gas inlet of the six-way valve to purge the six-way valve, and the gas is directly discharged after purging; the other way flows to the PDHID detector to purge the PDHID detector, the gas is discharged to the outside world from the detection gas outlet of the PDHID detector after purging, and the tenth solenoid valve is closed after purging is completed.

[0022] Further, the purging further comprises purging of a sample gas pipeline, specifically comprising the following steps: sample gas enters the six-way valve from the sample gas inlet, at this time the six-way valve is connected by the switch valve to connect the sample gas inlet and the sample gas outlet, the sample gas is discharged to the outside world from the sample gas outlet, and purging of the sample gas pipeline is realized.

[0023] Further, in the step, the heating rod heats the kdhf-0 type molecular sieve in the adsorption column to 100 DEG C.

[0024] The present application has the following advantages:

[0025] In the present embodiment, the SO2 gas is first adsorbed and then desorbed by using an adsorbent, so that the SO2 and SF6 are completely separated, the SO2 enters the chromatographic column later than the SF6, and thus a small amount of SF6 gas exists when the PDHID detector detects the SO2, so that the detection sensitivity and accuracy are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of the helium ion gas chromatograph according to Embodiment 1 of the present invention.

[0027] Figure 2 This is an enlarged view of the adsorption column in Example 1 of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] like Figure 1 As shown, this embodiment describes a helium ion gas chromatograph suitable for the detection of SF6 decomposition products, including a six-way valve 7, a quantitative loop 8, an adsorption column 12, a vacuum pump 14, a gas storage tank 18, a chromatographic column 23, a PDHID detector 14, and first to eleventh solenoid valves.

[0031] The carrier gas inlet 9 is connected to the carrier gas inlet 2 of the six-way valve, the carrier gas outlet 3 of the six-way valve is connected to the inlet of the adsorption column, the outlet of the adsorption column 12 is connected to the inlet of the chromatographic column 23, the outlet of the chromatographic column 23 is connected to the inlet of the PDHID detector 24, and the carrier gas inlet 9 is connected to the inlet of the PDHID detector 24.

[0032] A first solenoid valve 10 is connected in series between the carrier gas inlet 9 and the carrier gas inlet 2 of the six-way valve; a tenth solenoid valve 27 is connected in series between the carrier gas inlet 9 and the PDHID detector 24; a third solenoid valve 15, a seventh solenoid valve 20, and a ninth solenoid valve 22 are connected in series between the adsorption column 12 and the chromatographic column 23; the upstream of the ninth solenoid valve 22 and the upstream of the tenth solenoid valve 27 are connected in series through an eighth solenoid valve 21; a second solenoid valve 13, a vacuum pump 14, a fifth solenoid valve 17, a gas storage tank 18, and a sixth solenoid valve 19 are also connected in series between the outlet of the adsorption column 12 and the upstream of the ninth solenoid valve 22; a fourth solenoid valve 16 is also connected in series between the downstream of the third solenoid valve 15 and the outlet of the vacuum pump 14.

[0033] A check valve 25 is connected in series upstream of the detector outlet 26 of the PDHID detector 24. An eleventh solenoid valve 28 is connected in series upstream of the vacuum exhaust port 30 of the vacuum pump 14, and a vacuum gauge 29 is also installed at the vacuum exhaust port 30.

[0034] In this embodiment, the adsorption column 12 is also provided with a temperature sensor 11. The adsorption column 12 contains sufficient kdhf-03 type molecular sieve 122, which has good SO2 adsorption performance and no adsorption capacity for SF6 and helium. The molecular sieve 122 has a columnar structure, and a heating rod 121 is installed in the central through hole. The heating rod 121 is electrically heated and used to heat the molecular sieve 122 to desorb SO2.

[0035] In this embodiment, during operation, the sample gas (SF6 gas containing SO2 impurities) in the quantitative ring is introduced into the rear adsorption column by the carrier gas (helium). The adsorption column contains sufficient kdhf-03 type molecular sieve, which has good SO2 adsorption performance and no adsorption capacity for SF6 and helium. After the sample gas and carrier gas are left in the adsorption column for 3 minutes, SO2 gas is completely adsorbed. Then, the carrier gas containing only helium and SF6 gas after adsorption is purged into the rear chromatographic column for separation. After about 1 minute, the heating rod in the adsorption column is started to heat the molecular sieve to 100°C for desorption. The desorbed SO2 gas is introduced into a small gas tank using the carrier gas. After 1 minute, the valve is controlled to stop the carrier gas from entering the adsorption column. The vacuum pump is started for 3 minutes to exhaust all the residual gas in the adsorption column into the gas tank. Then, the vacuum pump is stopped, and the carrier gas is again controlled to flow through the adsorption column to push the gas in the gas tank into the rear chromatographic column. The SO2 gas in the gas is introduced into the PDHID detector, and the ultra-low concentration SO2 gas concentration is accurately detected without the interference of SF6 gas.

[0036] In this embodiment, the SO2 gas is first adsorbed and then desorbed by the adsorbent, so that SO2 and SF6 are completely separated. SO2 is then introduced into the chromatographic column with SF6, which avoids the presence of a small amount of SF6 when the PDHID detector detects SO2, thereby avoiding the presence of a small amount of SF6 gas when the PDHID detector detects SO2, reducing the detection sensitivity and accuracy.

[0037] Example 2

[0038] For example 1, this embodiment provides a detection method, as follows:

[0039] Step 1. Vacuum pumping; open the vacuum pump 14, open the second electromagnetic valve 13, the third electromagnetic valve 15, the sixth electromagnetic valve 19, the seventh electromagnetic valve 20, the eleventh electromagnetic valve 28, and close the other electromagnetic valves. Pump to the set value, generally 67 Pa is displayed on the vacuum gauge, then close the vacuum pump 14 and all electromagnetic valves;

[0040] Step 2. Purge; carrier gas (high purity helium) enters the device of Example 1 from carrier gas inlet 9, the first solenoid valve 10 and the tenth solenoid valve 27 are opened, one way flows to the six-way valve carrier gas inlet 2 to the six-way valve 7 for purging (purging effect is to exclude the previous residual gas interference, the same below), after purging, the gas is directly discharged; the other way flows to the PDHID detector 24, purges the PDHID detector 24, after purging, the gas is discharged from the detection gas outlet 26 of the PDHID detector 24 to the outside, and the tenth solenoid valve 27 is closed after purging is completed;

[0041] Sample gas (SF6 gas containing SO2 impurities) enters the six-way valve 7 from the sample gas inlet 6, at this time the six-way valve 7 connects the sample gas inlet 6 and the sample gas outlet 5 by switching, the sample gas is discharged from the sample gas outlet 5 to the outside, realizing purging of the sample gas pipeline.

[0042] Step 3. After purging is completed, the six-way valve 7 connects the sample gas inlet 6 and the dosing ring inlet 1 by switching, the sample gas enters the dosing ring 8, after a certain volume of gas is collected, the six-way valve 7 connects the carrier gas inlet 2, the dosing ring inlet 1, the dosing ring outlet 4 and the carrier gas outlet 3 in turn by switching, the carrier gas carries the sample gas in the dosing ring into the post adsorption column 12;

[0043] Step 4. After the sample gas containing carrier gas enters the adsorption column 12, all solenoid valves are closed, the gas is stored in the adsorption column 12, and after a certain period of standing (generally about 2 min), when the third solenoid valve 15, the seventh solenoid valve 20 and the ninth solenoid valve 22 are opened, only the gas containing helium and SF6 enters the post chromatographic column 23, after separation by the chromatographic column, enters the post PDHID detector 24, and after detection and analysis, is discharged from the detection gas outlet 26 to the outside;

[0044] Step 5. After the third solenoid valve 15 is opened for a set time, generally 3 minutes, the SF6 gas in the adsorption column 12 has been completely pushed out by the carrier gas and enters the chromatographic column 23, at which time the third solenoid valve 15 and the seventh solenoid valve 20 are closed, the six-way valve 7 is disconnected from the carrier gas inlet 2 and the quantitative ring 8 by a switch valve, the carrier gas enters the carrier gas inlet 2 and is directly discharged; at this time, the eighth solenoid valve 21 is opened, and the carrier gas continues to enter the chromatographic column 23; then, the heating rod in the adsorption column 12 is started to heat the kdhf-03 type molecular sieve to 100℃, and the temperature sensor 11 detects the temperature in the adsorption column, when the temperature reaches 100℃, the second solenoid valve 13 and the fifth solenoid valve 17 are opened, and the vacuum pump 14 is started to pump the desorbed SO2 to the gas storage tank 18, after a set time of vacuum pumping, all SO2 gas in the adsorption column 12 has been pumped to the gas storage tank 18, at which time the vacuum pump 14 is closed, the second solenoid valve 13, the seventh solenoid valve 20 and the eighth solenoid valve 21 are closed, and the third solenoid valve 15, the fourth solenoid valve 16, the fifth solenoid valve 17 and the sixth solenoid valve 19 are opened, the six-way valve 7 is switched to connect the carrier gas inlet 2 and the carrier gas outlet 3, the carrier gas continues to push the SO2 gas in the gas storage tank 18 to enter the post-stage chromatographic column 23, and then passes through the PDHID detector 24, is discharged to the outside from the detection gas outlet 26 after detection and analysis, after the SO2 detection result appears, all solenoid valves are closed, the gas inlet is stopped, and the detection process is ended.

[0045] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A helium ion gas chromatograph suitable for SF6 decomposition product detection, characterized in that, The six-way valve (7), the quantitative ring (8), the adsorption column (12), the vacuum pump (14), the gas storage tank (18), the chromatographic column (23), the PDHID detector (24) and the first to eleventh electromagnetic valves are included. The carrier gas inlet (9) is communicated with the carrier gas inlet (2) of the six-way valve, the carrier gas outlet (3) of the six-way valve is communicated with the inlet of the adsorption column, the outlet of the adsorption column (12) is communicated with the inlet of the chromatographic column (23), the outlet of the chromatographic column (23) is communicated with the inlet of the PDHID detector (24), and the carrier gas inlet (9) is communicated with the inlet of the PDHID detector (24). The first electromagnetic valve (10) is connected in series between the carrier gas inlet (9) and the carrier gas inlet (2) of the six-way valve, the tenth electromagnetic valve (27) is connected in series between the carrier gas inlet (9) and the PDHID detector (24), the third electromagnetic valve (15), the seventh electromagnetic valve (20) and the ninth electromagnetic valve (22) are connected in series between the adsorption column (12) and the chromatographic column (23), the upstream of the ninth electromagnetic valve (22) and the upstream of the tenth electromagnetic valve (27) are connected in series through the eighth electromagnetic valve (21), the second electromagnetic valve (13), the vacuum pump (14), the fifth electromagnetic valve (17), the gas storage tank (18) and the sixth electromagnetic valve (19) are further connected in series between the outlet of the adsorption column (12) and the upstream of the ninth electromagnetic valve (22), and the fourth electromagnetic valve (16) is further connected in series between the downstream of the third electromagnetic valve (15) and the outlet of the vacuum pump (14). The sample gas in the quantitative ring (8) is introduced into the rear-stage adsorption column (12) through the carrier gas, the sample gas and the carrier gas are placed in the adsorption column for a set time, SO2 gas is completely adsorbed, the gas containing only helium and SF6 gas after adsorption is blown to the rear-stage chromatographic column (23) for separation, the heating rod in the adsorption column (12) is started to heat the molecular sieve to 100 DEG C for desorption, the desorbed SO2 gas is introduced into the small gas storage tank (18) through the carrier gas, the valve is controlled to stop the carrier gas from entering the adsorption column (12) after a set time, the vacuum pump (14) is started to pump all residual gas in the adsorption column (12) into the gas storage tank (18), then the vacuum pump (14) is stopped, the carrier gas is made to flow through the adsorption column (12) again, the gas in the gas storage tank (18) is pushed into the rear-stage chromatographic column (23), and the SO2 gas in the gas enters the PDHID detector (24), so that the ultra-low concentration SO2 gas concentration is accurately detected without SF6 gas interference.

2. The helium ion gas chromatograph suitable for SF6 decomposition product detection according to claim 1, characterized in that, The check valve (25) is connected in series on the exhaust pipeline of the PDHID detector (24).

3. The helium ion gas chromatograph suitable for SF6 decomposition product detection according to claim 1 or 2, characterized in that, The eleventh electromagnetic valve (28) is installed on the exhaust pipeline of the vacuum pump (14).

4. The detection method of a helium ion gas chromatograph suitable for SF6 decomposition product detection according to claim 1, characterized in that, The detection method comprises the following steps: (1) vacuumizing; (2) purging; (3) After purging, the six-way valve (7) connects the sample gas inlet (6) and the quantitative ring inlet 1 through a switch valve, and the sample gas enters the quantitative ring (8). After collecting a certain volume of gas, the six-way valve (7) connects the carrier gas inlet (2), the quantitative ring inlet (1), the quantitative ring outlet (4), and the carrier gas outlet (3) in sequence through a switch valve. The carrier gas carries the sample gas in the quantitative ring into the post-stage adsorption column (12); (4) After the carrier gas containing the sample gas enters the adsorption column (12), all solenoid valves are closed, and the gas is stored in the adsorption column (12). After a certain period of standing, when the SO2 gas is fully adsorbed, the third solenoid valve (15), the seventh solenoid valve (20), and the ninth solenoid valve (22) are opened. Only the gas containing helium and SF6 enters the post-stage chromatographic column (23), and after separation by the chromatographic column, it enters the post-stage PDHID detector (24). After detection and analysis, it is discharged to the outside from the detection gas outlet (26); (5) After the third solenoid valve (15) is opened for a certain period of time, the SF6 gas in the adsorption column (12) has been completely pushed out by the carrier gas and enters the chromatographic column (23). At this time, the third solenoid valve (15) and the seventh solenoid valve (20) are closed, the six-way valve (7) is disconnected from the carrier gas inlet (2) and the quantitative ring (8) through a switch valve, and the carrier gas enters the carrier gas inlet (2) and is directly discharged. At this time, the eighth solenoid valve (21) is opened, and the carrier gas continues to enter the chromatographic column (23). Then, the heating rod in the adsorption column (12) is started and heated to a set temperature, and the second solenoid valve (13) and the fifth solenoid valve (17) are opened. The vacuum pump (14) is started, and the desorbed SO2 is pumped into the gas storage tank (18). After a certain period of vacuum pumping, all SO2 gas in the adsorption column (12) has been pumped into the gas storage tank (18). At this time, the vacuum pump (14) is closed, and the second solenoid valve (13), the seventh solenoid valve (20), and the eighth solenoid valve (21) are closed. The third solenoid valve (15), the fourth solenoid valve (16), the fifth solenoid valve (17), and the sixth solenoid valve (19) are opened, the six-way valve (7) is connected to the carrier gas inlet (2) and the carrier gas outlet (3) through a switch valve, and the carrier gas continues to push the SO2 gas in the gas storage tank (18) into the post-stage chromatographic column (23), and then through the PDHID detector (24). After detection and analysis, it is discharged to the outside from the detection gas outlet (26), and after the SO2 detection result appears, all solenoid valves are closed, the gas inlet is stopped, and the detection process is completed.

5. The detection method according to claim 4, characterized in that, Step (1) The specific method for vacuum pumping is: open the vacuum pump (14), open the second solenoid valve (13), the third solenoid valve (15), the sixth solenoid valve (19), the seventh solenoid valve (20), and the eleventh solenoid valve (28), and close the other solenoid valves. Vacuum pumping to a certain value, then close the vacuum pump (14), and close all solenoid valves.

6. The detection method according to claim 4, characterized in that, The specific method of purging in step (2) is: the carrier gas enters from the carrier gas inlet (9), the first electromagnetic valve (10) and the tenth electromagnetic valve (27) are opened, one way flows to the six-way valve carrier gas inlet (2) to purge the six-way valve (7), and the gas is directly discharged after purging; the other way flows to the PDHID detector (24) to purge the PDHID detector (24), and the gas is discharged from the detection gas outlet (26) of the PDHID detector (24) to the outside after purging, and the tenth electromagnetic valve (27) is closed after purging is completed.

7. The detection method according to claim 6, characterized in that, The purging also includes purging of the sample gas pipeline, specifically: the sample gas enters the six-way valve (7) from the sample gas inlet (6), at this time the six-way valve (7) connects the sample gas inlet (6) and the sample gas outlet (5) by a valve, the sample gas is discharged to the outside from the sample gas outlet (5), and the sample gas pipeline is purged.

8. The detection method according to claim 4, characterized in that, In step (5), the heating rod heats the kdhf-03 type molecular sieve in the adsorption column (12) to 100℃.

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