Chromatographic detection device and method

Abstract

The present invention provides a chromatogram detection device and a detection method, wherein the chromatogram detection device comprises a container, a combustion chamber, wherein the combustion chamber is arranged in the container, and the container has an inlet and an outlet; an air channel, wherein the air channel has a flow controller, and the air after flow control enters the container through a first branch and enters the combustion chamber through a second branch; a sample gas channel, wherein the sample gas channel is connected to the combustion chamber; a combustible gas channel, wherein the combustible gas channel has a switching unit, wherein the first outlet of the switching unit is connected to the combustion chamber through a third branch, and the second outlet is connected to the combustion chamber through a fourth branch; a first flow limiting unit, wherein the first flow limiting unit is arranged on the second branch; and a second flow limiting unit, wherein the second flow limiting unit is arranged on the fourth branch. The present invention has the advantages of simple structure and automation.

Description

Technical Field

[0001] The present invention relates to chromatographic analysis, and in particular to a chromatographic detection device and method. Background Art

[0002] In recent years, driven by national policies, the application of gas chromatography in the field of environmental protection has become more and more extensive. In order to improve the efficiency of on-site detection and the effectiveness of data measurement, online gas chromatography and portable gas chromatography came into being. With the increase in application scenarios, in order to meet the needs of different working conditions, the requirements for gas chromatography detectors are getting higher and higher. In some petrochemical industries, especially in places with explosion hazards, existing gas chromatography detectors (such as FID and FPD, etc.) cannot be used directly at the explosion site because they require a large power output and the presence of flames may cause combustion and explosion of combustible gases; and low-power detectors such as PID cannot meet the needs of on-site accurate detection due to limited detection capabilities.

[0003] In order to meet the detection needs of the petrochemical industry, especially in places with potential explosion hazards, the power of the detector needs to be limited, and the flame that causes the combustion and explosion of the combustible gas needs to be encapsulated in a relatively closed space to isolate the flame and energy source from the combustible gas environment. Compared with an open environment, it is relatively difficult for existing detectors to burn in a closed space and to discharge the generated water vapor out of the detector cavity. Existing detector technology has the following shortcomings:

[0004] 1. Not sufficient for use in explosive scenarios;

[0005] 2. After the detector flame is encapsulated in a confined space, the water vapor generated by the combustion cannot be discharged in time and flows back into the detector, which is not conducive to maintaining the flame temperature required for sample ionization; and forms a high temperature and high humidity environment, which is easy to cause accelerated aging of other components in the confined space and reduce their service life;

[0006] 3. If the generation of water vapor is reduced by reducing the hydrogen flow rate and increasing the combustion-supporting gas flow rate, ignition may become more difficult due to the decrease in the hydrogen-air ratio. Summary of the invention

[0007] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides a chromatographic detection device with high ignition success rate and automated operation and maintenance.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] A chromatographic detection device, comprising a container and a combustion chamber, wherein the combustion chamber is arranged in the container, and the container has an inlet and an outlet; the chromatographic detection device further comprises:

[0010] An air channel, wherein the air channel has a flow controller, and the air after flow control enters the container through a first branch and enters the combustion chamber through a second branch;

[0011] A sample gas channel, the sample gas channel being connected to the combustion chamber;

[0012] A combustible gas channel, wherein the combustible gas channel has a switching unit, wherein a first outlet of the switching unit is connected to the combustion chamber via a third branch, and a second outlet of the switching unit is connected to the combustion chamber via a fourth branch;

[0013] a first flow rate limiting unit, the first flow rate limiting unit being arranged on the second branch;

[0014] A second flow rate limiting unit is provided on the fourth branch.

[0015] The object of the present invention is also to provide a chromatographic detection method using the above-mentioned chromatographic detection device, and the object of the invention is achieved through the following technical solutions:

[0016] Chromatographic detection method, the chromatographic detection method comprising the following steps:

[0017] Ignition stage: In the air channel, the air with a flow rate of V1 passing through the flow controller is divided into two paths. The air enters the container through the first branch to purge the combustion chamber, and enters the combustion chamber after the flow rate is limited through the second branch.

[0018] In the combustible gas channel, the combustible gas flows out of the second outlet through the switching of the switching unit, and enters the combustion chamber for ignition after the flow rate is limited;

[0019] Operation stage: In the air channel, the air with a flow rate of V2 passing through the flow controller is divided into two paths, V2>V1, and enters the container through the first branch to purge the combustion chamber, and enters the combustion chamber after the flow rate is limited through the second branch;

[0020] In the combustible gas channel, the combustible gas flows out of the second outlet through the switching of the switching unit, enters the combustion chamber and burns after the flow rate is limited by the fourth branch, and maintains the flame; the water vapor in the container is discharged from the outlet of the container;

[0021] In the sample gas channel, the sample gas enters the combustion chamber.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. Through the design of setting flame retardants at the sealed container and the inlet and outlet, the chromatographic detection device can be used in dangerous places with explosion hazards;

[0024] 2. Adjust the ratio of air and combustible gas during the ignition stage and the operation stage to improve the ignition success rate;

[0025] 3. The air channel is designed to be divided into two branches, so that the water vapor in the sealed container is discharged through the large flow (first) branch, while the small flow (second) branch realizes ignition;

[0026] 4. The combustible gas channel is designed to be divided into two branches. The carbon deposits in the combustion chamber are cleaned through the large flow (third) branch, and ignition is achieved through the small flow (fourth) branch;

[0027] 5. The device is small in size, ingenious in design, and highly reliable. It is suitable for portable chromatography for continuous monitoring of pollution sources and volatile organic compounds in the air. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings:

[0029] Figure 1 1 is a simplified structural diagram of a chromatographic detection device according to Example 1-2 of the present invention. DETAILED DESCRIPTION

[0030] Figure 1 The following description describes the optional embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to teach the technical solution of the present invention, some conventional aspects have been simplified or omitted. It should be understood by those skilled in the art that variations or substitutions derived from these embodiments will be within the scope of the present invention. It should be understood by those skilled in the art that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional embodiments, but is only limited by the claims and their equivalents.

[0031] Embodiment 1:

[0032] Figure 1 The structure diagram of the chromatographic detection device according to the embodiment of the present invention is schematically shown as follows: Figure 1 As shown, the chromatographic detection device comprises:

[0033] A container 11, a combustion chamber, wherein the combustion chamber is arranged in the container, and the container has an inlet and an outlet;

[0034] An air channel, wherein the air channel has a flow controller, and the air after flow control enters the container through a first branch and enters the combustion chamber through a second branch;

[0035] A sample gas channel, the sample gas channel being connected to the combustion chamber;

[0036] A combustible gas channel, wherein the combustible gas channel has a switching unit, wherein a first outlet of the switching unit is connected to the combustion chamber via a third branch, and a second outlet of the switching unit is connected to the combustion chamber via a fourth branch;

[0037] a first flow rate limiting unit, the first flow rate limiting unit being arranged on the second branch;

[0038] a second flow rate limiting unit, the second flow rate limiting unit being arranged on the fourth branch;

[0039] Flame retardants 21-22 are respectively arranged at the inlet and outlet of the container.

[0040] In order to ignite and maintain flame, further, the second branch is connected to the sample channel so that air, sample gas and combustible gas are mixed before entering the combustion chamber.

[0041] The chromatographic detection method of the embodiment of the present invention, that is, the working process of the above-mentioned chromatographic detection device, comprises the following steps:

[0042] Ignition stage: In the air channel, the air with a flow rate of V1 passing through the flow controller is divided into two paths. The air enters the container through the first branch to purge the combustion chamber, and enters the combustion chamber after the flow rate is limited through the second branch.

[0043] In the combustible gas channel, the combustible gas flows out of the second outlet through the switching of the switching unit, and enters the combustion chamber for ignition after the flow rate is limited;

[0044] The sample gas channel is closed and no sample gas enters the combustion chamber;

[0045] Operation stage: In the air channel, the air with a flow rate of V2 passing through the flow controller is divided into two paths, V2>V1, and enters the container through the first branch to purge the combustion chamber, and enters the combustion chamber after the flow rate is limited through the second branch;

[0046] In the combustible gas channel, the combustible gas flows out of the second outlet through the switching of the switching unit, enters the combustion chamber and burns after the flow rate is limited by the fourth branch, and maintains the flame; the water vapor in the container is discharged from the outlet of the container;

[0047] In the sample gas channel, the sample gas enters the combustion chamber;

[0048] Maintenance stage: In the air channel, air enters the container through the first branch to purge the combustion chamber, and enters the combustion chamber after the flow rate is limited by the second branch;

[0049] Combustible gas channel: through the switching of the switching unit, the combustible gas flows out of the first outlet and enters the combustion chamber; the mixed air and combustible gas clean the deposited carbon on the surface of the combustion chamber;

[0050] In the above process, the proportion of combustible gas in the ignition stage is higher than that in the operation stage, thereby improving the ignition success rate; at the same time, in the first branch, air enters the container only through the pipeline; in the maintenance stage, in the fourth branch, combustible gas enters the combustion chamber only through the pipeline. This measure increases the flow rate of air or combustible gas in the channel, thereby improving the purge effect.

[0051] Embodiment 2:

[0052] An application example of the chromatographic detection device and method according to Example 1 of the present invention.

[0053] In this application example, a flow limiting unit adopts a flow limiter, and a switching unit adopts a three-way valve; a flow controller is set in the combustible gas channel to control the flow of air into the combustible gas in the channel; hydrogen is used as the combustible gas; the outlets of the third branch and the fourth branch are connected together, the second branch is connected to the sample gas channel, and then connected to the combustible gas channel, so that the air, sample gas and combustible gas are mixed before entering the combustion chamber; during the operation stage, the water vapor in the container is discharged from the container through the flame retardant 22.

Claims

1. According to the chromatographic detection method of the chromatographic detection device, the chromatographic detection device comprises a container and a combustion chamber, the combustion chamber is arranged in the container, and the container has an inlet and an outlet; The chromatographic detection device further comprises: An air channel, wherein the air channel has a flow controller, and after flow control, a path of air with a larger flow rate enters the container through a first branch to purge the combustion chamber, and another path of air with a smaller flow rate enters the combustion chamber through a second branch, and the second branch is connected to the sample gas channel and then to the combustible gas channel; A sample gas channel, the sample gas channel being connected to the combustion chamber; A combustible gas channel, wherein the combustible gas channel has a switching unit, wherein a first outlet of the switching unit is connected to the combustion chamber via a third branch, and a second outlet of the switching unit is connected to the combustion chamber via a fourth branch; a first flow rate limiting unit, the first flow rate limiting unit being arranged on the second branch; a second flow rate limiting unit, the second flow rate limiting unit being arranged on the fourth branch; The chromatographic detection method comprises the following steps: Ignition stage: In the air channel, the air with a flow rate of V1 passing through the flow controller is divided into two paths. The air enters the container through the first branch to purge the combustion chamber, and enters the combustion chamber after the flow rate is limited through the second branch. In the combustible gas channel, the combustible gas flows out of the second outlet through the switching of the switching unit, and enters the combustion chamber for ignition after the flow rate is limited; Operation phase: In the air channel, the air with a flow rate of V2 passing through the flow controller is divided into two paths, V2>V1, and enters the container through the first branch to purge the combustion chamber, and carries water vapor out of the container, and enters the sample gas channel after the flow rate is limited by the second branch. The air mixes with the sample gas in the sample gas channel, and then enters the combustible gas channel, and finally enters the combustion chamber; In the combustible gas channel, the combustible gas flows out of the second outlet through the switching of the switching unit, and after the flow rate is limited by the fourth branch, it is mixed with the mixed gas of air and sample gas, and finally enters the combustion chamber to burn and maintain the flame; the water vapor in the container is discharged from the outlet of the container; In the sample gas channel, the sample gas enters the combustion chamber.

2. The chromatographic detection method according to claim 1, characterized in that: The chromatographic detection method further comprises: Maintenance stage: In the air channel, air enters the container through the first branch to purge the combustion chamber, and enters the combustion chamber after the flow rate is limited by the second branch; Combustible gas passage: by switching the switching unit, the combustible gas flows out of the first outlet and enters the combustion chamber; the mixed air and combustible gas clean the deposited carbon on the surface of the combustion chamber.

3. The chromatographic detection method according to claim 1, characterized in that: In the first branch, air enters the container only through the pipe.

4. The chromatographic detection method according to claim 2, characterized in that: During the maintenance phase, in the fourth branch, combustible gas enters the combustion chamber only through the pipeline.

5. The chromatographic detection method according to claim 1, characterized in that: The combustible gas is hydrogen.

6. The chromatographic detection method according to claim 1, characterized in that: The water vapor passes through the flame retardant and flows out of the container.

7. The chromatographic detection method according to claim 2, characterized in that: Air and combustible gas are mixed and then enter the combustion chamber.

8. The chromatographic detection method according to claim 1, characterized in that: The inlet and outlet of the container are respectively provided with flame retardants.

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