Gas chromatography carrier gas drying system

Abstract

The utility model provides a gas chromatography carrier gas drying system which is characterized in that a first four-way valve and a second four-way valve are arranged, a first drying pipe and a second drying pipe are arranged between the first four-way valve and the second four-way valve in parallel, and the first drying pipe is arranged in a first heating box; according to the system, through cooperative use of the devices, when a drying agent in one drying pipe is inactivated, the states of the first four-way valve and the second four-way valve are switched, the other drying pipe is replaced for working, the drying agent in the other drying pipe is replaced for working, and therefore the drying efficiency is improved. Meanwhile, the arranged heating box can heat the drying pipe located in the heating box, back-blowing air supplied by a back-blowing air source is utilized to take away heated and desorbed water vapor from the drying pipe, regeneration of the drying agent in the drying pipe is achieved, and the defects that in the using process of an existing gas chromatograph, a chromatograph needs to be started and stopped when the drying agent of drying carrier gas is regenerated, and the regeneration efficiency is high are overcome. And the service life of the chromatographic instrument is shortened.

Description

Technical Field

[0001] The present application relates to the technical field of gas chromatography analysis, and in particular to a gas chromatography carrier gas drying system. Background Art

[0002] Gas chromatography is one of the indispensable analytical instruments in chemical production and is widely used. The carrier gas used in gas chromatography has high requirements, so the tubular dryer has become one of the indispensable accessories for gas chromatography. Especially for the chromatographic system using a gas generator, it is easier to replace water into the chromatographic system than the cylinder carrier gas, which leads to the failure of the chromatographic column and the reduction of the life of the detector. Therefore, it is particularly important to remove moisture and dust in the chromatographic carrier gas system. Usually, the laboratory uses a tubular dryer, which is filled with solid desiccant, usually silica gel. However, the solid desiccant used in this method will become ineffective after absorbing water. The solid desiccant needs to be taken out of the drying tube for drying and activation. The process is relatively cumbersome and the chromatogram needs to be started and stopped. If the water content in the system is too high, the solid desiccant will be deactivated very quickly, and the replacement frequency will increase, resulting in frequent start and stop operations of the chromatogram, which will reduce the service life of the chromatogram. Utility Model Content

[0003] The present application provides a gas chromatography carrier gas drying system to solve the problem that during the use of the above-mentioned existing gas chromatography, the chromatograph needs to be started and stopped when regenerating the desiccant for drying the carrier gas, thereby reducing the service life of the chromatograph.

[0004] The present application provides a gas chromatography carrier gas drying system, comprising a carrier gas source, a first four-way valve, a first drying tube, a second four-way valve and a gas chromatograph connected in series in sequence;

[0005] The second interface of the first four-way valve is connected to the carrier gas source, and the third interface is connected to the input end of the first drying tube;

[0006] The second interface of the second four-way valve is connected to the output end of the first drying tube, and the third interface is connected to the gas chromatograph;

[0007] The first interface of the first four-way valve is connected to the fourth interface of the second four-way valve through the second drying pipe;

[0008] The fourth interface of the first four-way valve is connected to the exhaust gas treatment device;

[0009] The first interface of the second four-way valve is connected to the back-blowing gas source;

[0010] The first drying tube is arranged in the first heating box; the second drying tube is arranged in the second heating box.

[0011] Optionally, the first four-way valve and the second four-way valve can both be switched between a first state and a second state;

[0012] In the first state, the second interface of the four-way valve is connected to the third interface, and the first interface is connected to the fourth interface;

[0013] In the second state, the second interface of the four-way valve is communicated with the first interface, and the third interface is communicated with the fourth interface.

[0014] Optionally, the system further comprises a controller, and the first four-way valve, the second four-way valve, the first drying tube and the second drying tube are all electrically connected to the controller.

[0015] Optionally, a first moisture meter is provided between the first drying tube and the second four-way valve;

[0016] A second moisture measuring instrument is provided between the second drying tube and the second four-way valve;

[0017] The first moisture meter and the second moisture meter are both electrically connected to the controller.

[0018] Optionally, the first drying tube comprises a shell;

[0019] Openings are arranged at both ends of the shell, and the shell includes a desiccant filling layer and an indicator layer arranged at both ends of the desiccant filling layer;

[0020] The indicating layer comprises a moisture indicating layer and an isolation mesh layer arranged on both sides of the moisture indicating layer.

[0021] Optionally, the first heating box comprises a heating box housing having upper and lower parts hingedly connected;

[0022] Openings are provided at both ends of the heating box shell for the pipe to pass through; a plurality of brackets for supporting the first drying tube are arranged in an array along the length direction of the heating box shell inside the heating box shell, and the brackets are perpendicular to the axis of the heating box shell;

[0023] A heating module matching the first drying tube is arranged between the multiple brackets and in the space between the brackets and the heating box shell.

[0024] Optionally, the heating module comprises a waterproof layer, a heat-conducting layer, a heating layer, a heat-reflecting layer and a heat-insulating layer layer by layer along the direction from the outer side wall of the first drying tube to the outside of the first drying tube.

[0025] Optionally, the tail gas treatment device includes a combustion furnace and an activated carbon adsorption tower connected in series.

[0026] The gas chromatography carrier gas drying system provided in the present application is configured such that when the desiccant in one of the drying tubes is deactivated, the state of the first four-way valve and the second four-way valve are switched to another drying tube to operate. A heating box is provided at the same time to heat and desorb the drying tube in the heating box. The desorbed water vapor is carried away from the drying tube by the back-blowing gas supplied by the back-blowing gas source to achieve regeneration of the desiccant in the drying tube, thereby achieving the purpose of online regeneration of the desiccant, and overcoming the disadvantage of the existing gas chromatography that the chromatograph needs to be started and stopped when regenerating the desiccant for the carrier gas during use, thereby reducing the service life of the chromatograph. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of a gas chromatography carrier gas drying system provided in one embodiment of the present application;

[0029] Figure 2 A schematic diagram of a first state of a four-way valve provided in an embodiment of the present application;

[0030] Figure 3 A schematic diagram of a second state of a four-way valve provided in an embodiment of the present application;

[0031] Figure 4 A schematic diagram of a gas chromatography carrier gas drying system is provided for another embodiment of the present application;

[0032] Figure 5 A schematic diagram of a gas chromatography carrier gas drying system is provided for another embodiment of the present application;

[0033] Figure 6 A schematic diagram of the structure of a first drying tube provided in one embodiment of the present application;

[0034] Figure 7 A schematic diagram of the internal structure of the first heating box provided in one embodiment of the present application when in operation;

[0035] Figure 8 A schematic diagram of the internal disassembly of a first heating box provided in an embodiment of the present application;

[0036] Fig. 9 A schematic diagram of the cross-sectional structure of a heating module provided in one embodiment of the present application;

[0037] Fig.10A schematic diagram of an exhaust gas treatment device provided in one embodiment of the present application.

[0038] Description of reference numerals:

[0039] 1. carrier gas source; 2. first drying tube; 3. gas chromatograph; 4. second drying tube; 5. tail gas treatment device; 6. back-blowing gas source; 7. controller; 10. first four-way valve; 20. second four-way valve; 21. first heating box; 22. shell; 41. second heating box; 51. combustion furnace; 52. activated carbon adsorption tower; 100. first moisture meter; 200. second moisture meter; 211. heating box shell; 212. bracket; 213. heating module; 221. desiccant filling layer; 222. indication layer; 2221. moisture indication layer; 2222. isolation net layer; 2131. waterproof layer; 2132. heat conductive layer; 2133. heating layer; 2134. heat reflecting layer; 2135. thermal insulation layer. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0041] like Figure 1 As shown, the present application provides a gas chromatography carrier gas drying system, comprising a carrier gas source 1, a first four-way valve 10, a first drying tube 2, a second four-way valve 20 and a gas chromatograph 3 connected in series in sequence;

[0042] The second interface of the first four-way valve 10 is connected to the carrier gas source 1, and the third interface is connected to the input end of the first drying tube 2;

[0043] The second interface of the second four-way valve 20 is connected to the output end of the first drying tube 2, and the third interface is connected to the gas chromatograph 3;

[0044] The first interface of the first four-way valve 10 is connected to the fourth interface of the second four-way valve 20 through the second drying pipe 4;

[0045] The fourth interface of the first four-way valve 10 is connected to the exhaust gas treatment device 5;

[0046] The first interface of the second four-way valve 20 is connected to the back-blowing gas source 6;

[0047] The first drying tube 2 is disposed in the first heating box 21 ; the second drying tube 4 is disposed in the second heating box 41 .

[0048] The gas chromatography carrier gas drying system provided in the present application is provided with a first four-way valve 10 and a second four-way valve 20, and a first drying tube 2 and a second drying tube 4 are provided in parallel between the first four-way valve 10 and the second four-way valve 20, and the first drying tube 2 is provided in a first heating box 21; the second drying tube 4 is provided in a second heating box 41, and the second four-way valve 20 is connected to a back-blowing gas source 6. When the desiccant in one of the drying tubes is inactivated, the state of the first four-way valve 10 and the second four-way valve 20 is switched to another drying tube to work. The heating box provided at the same time can heat and desorb the drying tube in the heating box, and the back-blowing gas supplied by the back-blowing gas source 6 is used to carry the desorbed water vapor away from the drying tube to achieve the regeneration of the desiccant in the drying tube, thereby achieving the purpose of online regeneration of the desiccant, overcoming the disadvantage that the existing gas chromatograph needs to start and stop the chromatograph when regenerating the desiccant of the dry carrier gas during use, thereby reducing the service life of the chromatograph.

[0049] like Figure 2 and Figure 3 As shown, optionally, the first four-way valve 10 and the second four-way valve 20 can both be switched between a first state and a second state;

[0050] In the first state, the second interface of the four-way valve is connected to the third interface, and the first interface is connected to the fourth interface;

[0051] In the second state, the second interface of the four-way valve is communicated with the first interface, and the third interface is communicated with the fourth interface.

[0052] In the present application, the first four-way valve 10 and the second four-way valve 20 can both switch between the first state and the second state. The first four-way valve 10 and the second four-way valve 20 have the same structure and can achieve different connection purposes by switching between different states.

[0053] In the initial state, the first four-way valve 10 and the second four-way valve 20 are both in the first state. When in use, the carrier gas output by the carrier gas source 1 (the carrier gas in this application is the water-containing hydrogen generated by the gas generator) enters the first drying tube 2 through the second interface and the third interface of the first four-way valve 10, and is adsorbed by the desiccant packing layer 221 in the first drying tube 2 to dry the carrier gas and remove excess water in the carrier gas. The carrier gas after dehydration enters the gas chromatograph 3 through the second interface and the third interface of the second four-way valve 20, and is detected after being mixed with the sample gas.

[0054] When the first drying tube 2 works for a period of time, which is 48 hours in the present application (or a small amount of color-changing silica gel is loaded into the first drying tube 2 as an indicator, taking the blue cobalt-containing color-changing silica gel as an example, when it turns red), the first four-way valve 10 and the second four-way valve 20 are cut off, and the first four-way valve 10 and the second four-way valve 20 are both switched to the second state.

[0055] At this time, the carrier gas from the carrier gas source 1 will enter the second drying tube 4 through the second interface and the first interface of the first four-way valve in turn for drying. The dried carrier gas will enter the gas chromatograph 3 through the fourth interface and the third interface of the second four-way valve 20 and mix with the sample gas for detection.

[0056] During the above process, when the first four-way valve 10 and the second four-way valve 20 are both switched to the second state, the first drying pipe 2 enters the regeneration procedure.

[0057] During the regeneration process, the first heating box 21 is turned on, and the first heating box 21 generates heat to heat the first drying tube 2 to a preset temperature (105°C ± 3°C in this application). A thermocouple can be set in the first heating box 21 to feed back the temperature data to the operator, so as to realize controlled heating of the drying tube. At the same time, the back-blowing gas source 6 blows the back-blowing gas (nitrogen or other inert gas in this application) into the first drying tube 2 from the first interface and the second interface of the second four-way valve 20 to take away the moisture desorbed during the heating process of the first drying tube 2, so that the desiccant (a desiccant mixed with activated carbon and silica gel in a volume ratio of 1:1 in this application) in the first drying tube 2 is regenerated. The regeneration process lasts for 2 hours (starting from the temperature of the first drying tube 2 rising to the preset drying temperature), and it can be considered that the regeneration of the desiccant in the first drying tube 2 is completed, and the first drying tube 2 is in a standby state.

[0058] Similarly, when the desiccant in the second drying tube 4 is deactivated and needs to be dried, the operator controls the first four-way valve 10 and the second four-way valve 20 to cut the valves, so that the second drying tube 4 enters the regeneration process and the first drying tube 2 enters the working state.

[0059] like Figure 4 As shown, optionally, the system of the present application further includes a controller 7 , and the first four-way valve 10 , the second four-way valve 20 , the first heating box 21 and the second heating box 41 are all electrically connected to the controller 7 .

[0060] In the present application, the first four-way valve 10, the second four-way valve 20, the first heating box 21 and the second heating box 41 are all electrically connected to the controller 7, and the opening and closing of the first heating box 21 and the second heating box 41 can be remotely controlled by the controller 7; as well as the switching of the first four-way valve 10 and the second four-way valve 20, which has the advantages of being automatic and real-time.

[0061] like Figure 5 As shown, optionally, a first moisture meter 100 is provided between the first drying pipe 2 and the second four-way valve 20;

[0062] A second moisture meter 200 is provided between the second drying pipe 4 and the second four-way valve 20;

[0063] The first moisture meter 100 and the second moisture meter 200 are both electrically connected to the controller 7 .

[0064] In the present application, the first moisture meter 100 is used to monitor the moisture content in the carrier gas discharged from the first drying tube 2 and feed back the data to the controller 7. When the first moisture meter 100 detects that the moisture content in the carrier gas discharged from the first drying tube 2 exceeds a preset upper limit value, the first moisture meter 100 feeds back the measured moisture data to the controller 7. The controller 7 controls the first four-way valve 10 and the second four-way valve 20 to cut the valves, the first drying tube 2 enters the regeneration process, and the second drying tube 4 enters the working state.

[0065] Similarly, the second moisture meter 200 is used to monitor the moisture content in the carrier gas discharged from the second drying tube 4 and feed the data back to the controller 7. Its working process is similar to that of the first moisture meter 100 and will not be described again here.

[0066] like Figure 6 As shown, optionally, the first drying tube 2 includes a shell 22;

[0067] The shell 22 has openings at both ends. The shell 22 includes a desiccant filling layer 221 and an indicator layer 222 disposed at both ends of the desiccant filling layer 221.

[0068] The indication layer 222 includes a moisture indication layer 2221 and an isolation mesh layer 2222 disposed on both sides of the moisture indication layer 2221 .

[0069] In the present application, the desiccant filler layer 221 is made of activated carbon and silica gel mixed in a certain volume ratio, for example, activated carbon and silica gel are mixed in a volume ratio of 1:1.

[0070] The purpose of the isolation mesh layer 2222 is mainly to isolate the desiccant filling layer 221 and the moisture indicating layer 2221. The material of the isolation mesh layer 2222 is, for example, polyamide. The moisture indicating layer 2221 is filled with blue cobalt-containing silica gel to indicate whether the desiccant filling layer 221 is inactivated. In the present application, the volume ratio of the desiccant filling layer 221 to the indicating layer 222 is 10:1. In the present application, the second drying tube 4 has the same structure as the first drying tube 2.

[0071] like Figure 7 and Figure 8 As shown, optionally, the first heating box 21 includes a heating box housing 211 with upper and lower parts hingedly connected;

[0072] Both ends of the heating box housing 211 are provided with openings for the pipe to pass through; a plurality of brackets 212 for supporting the first drying tube 2 are arranged in an array along the length direction of the heating box housing 211 in the heating box housing 211, and the brackets 212 are perpendicular to the axis of the heating box housing 211;

[0073] A heating module 213 matching the first drying tube 2 is arranged between the multiple brackets 212 and in the space between the brackets 212 and the heating box housing 211 .

[0074] In the present application, a groove matching the shape of the first drying tube 2 is provided on the bracket 212 to facilitate fixing the first drying tube 2 in the first heating box 21 .

[0075] In the present application, the shape of the housing 211 is not limited, and its shape can be a rectangular parallelepiped, or Figure 7 and Figure 8 The semi-cylindrical shape shown, or other shapes that can achieve the functions of the above-mentioned shell 211.

[0076] like Fig. 9 As shown, optionally, the heating module 213 includes a waterproof layer 2131, a heat conductive layer 2132, a heating layer 2133, a heat reflective layer 2134 and a heat insulating layer 2135 layer by layer along the direction from the outer wall of the first drying tube 2 to away from the outside of the first drying tube 2.

[0077] In the present application, the waterproof layer 2131 is, for example, a thin film layer formed by a high temperature resistant polymer material, and the thickness of the waterproof layer 2131 is 0.5-1 mm.

[0078] The heat-conducting layer 2132 is a heat-conducting layer with a thickness of 3 to 5 mm and is filled with graphite powder; the heating layer 2133 is, for example, a ceramic heating layer, which generates heat by energizing a resistance wire; the purpose of the heat-reflecting layer 2134 is to reduce heat loss, and its material is, for example, aluminum foil; the thermal insulation layer 2135 plays the role of heat preservation, reducing heat loss, and saving energy, and its material is, for example, rock wool, foamed polyurethane and other materials.

[0079] In the present application, a waterproof layer 2131 and a heat-conducting layer 2132 are provided between the heating layer 2133 and the first drying tube 2 to be heated, the purpose of which is mainly to prevent the heating layer 2133 from being in direct contact with the first drying tube 2, resulting in uneven heating, causing the desiccant to coke due to excessively high temperature, or the temperature to be too low, resulting in poor drying effect. Moreover, heat is transferred through the heat-conducting layer 2132, which can prevent the occurrence of such uneven heating. Since the present application adopts an electric heating method, the waterproof layer 2131 is provided to prevent moisture from entering the heating layer 2133, resulting in the adverse consequence of a short circuit of the resistance wire of the heating layer 2133.

[0080] In one practicable manner, the heating module 213 is detachably fixed in the heating box housing 211, and the waterproof layer 2131 should cover the entire surface of the heating module 213. In the present application, the second heating box 41 has the same structure as the first heating box 21. A thermocouple electrically connected to the controller 7 is provided in the heat conductive layer 2132 for real-time monitoring of the heating temperature.

[0081] like Fig.10 As shown, optionally, the tail gas treatment device 5 includes a combustion furnace 51 and an activated carbon adsorption tower 52 which are connected in series.

[0082] In the present application, the components of the desiccant include activated carbon, which will inevitably adsorb other substances during long-term use, especially the carrier gas generated by the gas generator. These substances adsorbed by the activated carbon will be desorbed and carried away by the backblowing gas during the regeneration process of the desiccant. If they are directly discharged without treatment, they may cause pollution to the experimental environment. Therefore, a combustion furnace 51 is set to burn these gases for harmless treatment, and then they are absorbed and treated by an activated carbon adsorption tower 52.

[0083] A gas chromatography carrier gas drying system, the working process of which is as follows:

[0084] In the initial state, the first four-way valve 10 and the second four-way valve 20 are both in the first state. When in use, the carrier gas output by the carrier gas source 1 (the carrier gas in this application is the water-containing hydrogen generated by the gas generator) enters the first drying tube 2 through the second interface and the third interface of the first four-way valve 10, and is adsorbed by the desiccant packing layer 221 in the first drying tube 2 to dry the carrier gas and remove excess water in the carrier gas. The carrier gas after dehydration enters the gas chromatograph 3 through the second interface and the third interface of the second four-way valve 20, and is detected after being mixed with the sample gas.

[0085] When the first moisture meter 100 detects that the moisture content in the carrier gas discharged from the first drying tube 2 exceeds a preset upper limit value (or the operator observes that the color-changing silica gel in the moisture indicating layer 2221 in the first drying tube 2 changes from blue to pink), the first moisture meter 100 feeds back the measured moisture data to the controller 7, and the controller 7 controls the first four-way valve 10 and the second four-way valve 20 to cut the valves, and the first four-way valve 10 and the second four-way valve 20 are both switched to the second state.

[0086] At this time, the carrier gas from the carrier gas source 1 will pass through the second interface and the first interface of the first four-way valve 10 in turn and enter the second drying tube 4 for drying. The dried carrier gas (while being monitored in real time by the second moisture meter 200) will pass through the fourth interface and the third interface of the second four-way valve 20 and enter the gas chromatograph 3 to mix with the sample gas for detection.

[0087] When the first moisture meter 100 detects that the moisture content in the carrier gas discharged from the first drying tube 2 exceeds the preset upper limit, the controller 7 controls the first four-way valve 10 and the second four-way valve 20 to switch to the second state. At this time, the first drying tube 2 enters the regeneration process.

[0088] During the regeneration process, the controller 7 controls the first heating box 21 to turn on, and the heating layer 2133 (resistance wire heating in this application) in the heating module 213 in the first heating box 21 generates heat to heat the first drying tube 2 to a preset temperature (105°C ± 3°C in this application). A thermocouple can be set in the heat conductive layer 2132 to feed back the temperature data to the controller 7, so as to realize controlled heating of the drying tube. At the same time, the back-blowing gas source 6 blows the back-blowing gas (nitrogen or other inert gas in the present application) into the first drying tube 2 from the first interface and the second interface of the second four-way valve 20 to take away the moisture desorbed during the heating process of the first drying tube 2, so that the adsorbent (a dehydrated adsorbent mixed by volume of activated carbon and silica gel in the present application at a ratio of 1:1) in the desiccant filling layer 221 in the first drying tube 2 is regenerated. The regeneration process lasts for 2 hours (starting from the temperature of the first drying tube 2 rising to the preset drying temperature. This step can be set as a program in the controller 7 to control the first heating box 21 to stop heating after a preset time), or when the operator observes that the moisture indicator of the moisture indicator layer 2221 in the first drying tube 2 away from the first moisture meter 100 restores the color when it is anhydrous (for example, in the present application, blue cobalt-containing silica gel is used as the indicator. When the operator observes that the silica gel as the moisture indicator restores to blue), it can be considered that the desiccant in the first drying tube 2 is regenerated and the first drying tube 2 is in a standby state.

[0089] Similarly, when the second moisture meter 200 detects that the moisture content of the carrier gas discharged from the second drying tube 4 exceeds a preset upper limit value, the second moisture meter 200 feeds back the data to the controller 7, and the controller 7 controls the first four-way valve 10 and the second four-way valve 20 to cut the valves, so that the second drying tube 4 enters the regeneration process, and the first drying tube 2 enters the working state.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A gas chromatography carrier gas drying system, characterized in that: It comprises a carrier gas source (1), a first four-way valve (10), a first drying tube (2), a second four-way valve (20) and a gas chromatograph (3) which are sequentially connected in series; The second interface of the first four-way valve (10) is connected to the carrier gas source (1), and the third interface is connected to the input end of the first drying tube (2); The second interface of the second four-way valve (20) is connected to the output end of the first drying tube (2), and the third interface is connected to the gas chromatograph (3); The first interface of the first four-way valve (10) is connected to the fourth interface of the second four-way valve (20) via a second drying pipe (4); The fourth interface of the first four-way valve (10) is connected to the exhaust gas treatment device (5); The first interface of the second four-way valve (20) is connected to a back-blowing gas source (6); The first drying tube (2) is arranged in a first heating box (21); and the second drying tube (4) is arranged in a second heating box (41).

2. The gas chromatography carrier gas drying system according to claim 1, characterized in that: The first four-way valve (10) and the second four-way valve (20) can both be switched between a first state and a second state; The first state is that the second interface of the four-way valve is connected to the third interface, and the first interface is connected to the fourth interface; The second state is that the second interface of the four-way valve is connected to the first interface, and the third interface is connected to the fourth interface.

3. The gas chromatography carrier gas drying system according to claim 1, characterized in that: The system further comprises a controller (7), and the first four-way valve (10), the second four-way valve (20), the first drying pipe (2) and the second drying pipe (4) are all electrically connected to the controller (7).

4. The gas chromatography carrier gas drying system according to claim 3, characterized in that: A first moisture meter (100) is provided between the first drying tube (2) and the second four-way valve (20); A second moisture meter (200) is provided between the second drying pipe (4) and the second four-way valve (20); The first moisture meter (100) and the second moisture meter (200) are both electrically connected to the controller (7).

5. The gas chromatography carrier gas drying system according to claim 1, characterized in that: The first drying tube (2) comprises a shell (22); The shell (22) is provided with openings at both ends, and the shell (22) includes a desiccant filling layer (221) and an indication layer (222) provided at both ends of the desiccant filling layer (221); The indication layer (222) comprises a moisture indication layer (2221) and an isolation mesh layer (2222) arranged on both sides of the moisture indication layer (2221).

6. The gas chromatography carrier gas drying system according to claim 1, characterized in that: The first heating box (21) comprises a heating box shell (211) with upper and lower parts hingedly connected; Openings are provided at both ends of the heating box shell (211) for the pipe to pass through; a plurality of brackets (212) for supporting the first drying tube (2) are arranged in an array along the length direction of the heating box shell (211) inside the heating box shell (211); the brackets (212) are perpendicular to the axis of the heating box shell (211); A heating module (213) matching the first drying tube (2) is arranged in the space between the plurality of brackets (212) and in the space between the brackets and the heating box shell (211).

7. The gas chromatography carrier gas drying system according to claim 6, characterized in that: The heating module (213) comprises, layer by layer, a waterproof layer (2131), a heat-conducting layer (2132), a heating layer (2133), a heat-reflecting layer (2134) and a heat-insulating layer (2135) along a direction close to the outer side wall of the first drying tube (2) and away from the outside of the first drying tube (2).

8. The gas chromatography carrier gas drying system according to any one of claims 1 to 7, characterized in that: The tail gas treatment device (5) comprises a combustion furnace (51) and an activated carbon adsorption tower (52) which are connected in series.

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