gas chromatograph

Abstract

To provide a gas chromatograph that has no risk of explosion when hydrogen is used as carrier gas and that does not require tubing or piping to exhaust the carrier gas.SOLUTION: The gas chromatograph includes a sample introduction unit (2) in which a vaporized sample is introduced into a separation column (4) together with a carrier gas and a detection unit (5) for detecting the gas discharged from the separation column. The gas chromatograph has a catalyst processing unit (10) that includes a catalyst for oxidizing hydrogen gas by introducing a gas including the carrier gas discharged from the sample introduction unit or the detection unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas chromatograph, and more particularly to a gas chromatograph that uses hydrogen as a carrier gas.

Background Art

[0002] A gas chromatograph introduces a vaporized sample into a column together with a carrier gas and detects the sample separated by the column with a detector. As the carrier gas for separating the sample, an inert gas is generally used, and mainly helium, argon, nitrogen, hydrogen, etc. are used.

[0003] In a sample introduction unit that introduces a sample into a column, as shown in Patent Document 1, in order to control the amount of sample introduced into the column, it has a configuration for discharging unnecessary carrier gas and sample to the outside of the gas chromatograph.

[0004] Also, in a detector that detects the gas discharged from the column, as shown in Patent Document 2, the carrier gas containing the sample is generally discharged to the outside after passing through the detector.

[0005] When hydrogen is used as the carrier gas, there was a concern that the used carrier gas was discharged to the outside of the gas chromatograph and the discharged hydrogen accumulated in the test chamber and caused an explosion. Therefore, measures have been taken to attach a tube or pipe to the gas discharge port and discharge hydrogen to an exhaust system such as outdoors or a draft chamber.

[0006] However, it is necessary to install the gas chromatograph in consideration of tubes and pipes, which has caused problems such as the installation location of the gas chromatograph being restricted, or the space occupied by the tubes and pipes restricting the installation of other devices and the working space. Also, when exhausting hydrogen using an exhaust system such as a draft chamber, there was a problem that pressure fluctuations from the exhaust system were transmitted to the gas chromatograph through the tubes and pipes, deteriorating the analysis performance due to vibration noise.

Prior Art Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2020-118616 [Patent Document 2] Japanese Patent Application Publication No. 7-43356 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The present invention was made to solve the above problems, and its objective is to provide a gas chromatograph that eliminates the risk of explosion even when hydrogen is used as the carrier gas, and that does not require tubes or piping for exhausting the carrier gas. [Means for solving the problem]

[0009] One embodiment of the gas chromatograph according to the present invention, which was developed to solve the above problems, is as follows. A gas chromatograph comprising a sample introduction unit for introducing a vaporized sample together with a carrier gas into a separation column, and a detection unit for detecting the gas discharged from the separation column, wherein the gas chromatograph further comprises a catalyst section equipped with a catalyst for introducing the gas containing the carrier gas discharged from the sample introduction unit or the detection unit and oxidizing the hydrogen gas. [Effects of the Invention]

[0010] According to the above embodiment of the gas chromatograph of the present invention, the gas containing the carrier gas discharged from the sample introduction unit or detection unit is introduced into a catalytic processing unit equipped with a catalyst that oxidizes hydrogen gas, so that the hydrogen gas is oxidized and converted into water. As a result, hydrogen is not discharged from the gas chromatograph, eliminating the need for equipment such as tubes and piping, and also suppressing limitations on the installation location of the gas chromatograph and deterioration of analytical performance due to vibration noise. [Brief explanation of the drawing]

[0011] [Figure 1] A schematic diagram illustrating a first embodiment of the gas chromatograph of the present invention. [Figure 2] A schematic diagram illustrating the transfer of heat in the gas chromatograph of the present invention. [Figure 3] A schematic diagram illustrating a second embodiment of the gas chromatograph of the present invention. [Figure 4] A schematic diagram illustrating a third embodiment of the gas chromatograph of the present invention. [Modes for carrying out the invention]

[0012] The gas chromatograph of the present invention will be described in detail with reference to Figures 1 to 4. The present invention is characterized by a gas chromatograph comprising a sample introduction unit for introducing a vaporized sample together with a carrier gas into a separation column, and a detection unit for detecting the gas discharged from the separation column, wherein the gas chromatograph has a catalyst processing unit equipped with a catalyst for introducing the gas containing the carrier gas discharged from the sample introduction unit or the detection unit and oxidizing the hydrogen gas.

[0013] The sample introduction section is equipped with a sample vaporization chamber 2, which vaporizes the sample and mixes the vaporized sample with the carrier gas introduced into the vaporization chamber before introducing it into the column 4. The vaporization chamber 2 is connected to an injector 1 for introducing the sample and a carrier gas introduction section (not shown).

[0014] Various configurations can be used for the sample vaporization chamber, such as the one shown in Patent Document 1. Typically, the inlet is kept at a high temperature (150-250°C, maximum 450°C) to instantly vaporize the injected sample. The vaporized sample is mixed with the carrier gas. In the case of samples containing high-concentration components or non-volatile or highly persistent contaminants, only a portion of the sample and carrier gas are introduced into the column, and the amount of sample introduced into the column is controlled. Any material or carrier gas not introduced into the column is discharged outside the vaporization chamber 2.

[0015] In the present invention, the gas containing the carrier gas discharged from the vaporization chamber 2 is introduced into the catalyst treatment unit 10 through the pipe (flow path) 7. The gas from the vaporization chamber 2 can be directly introduced into the catalyst treatment unit 10, but as shown in FIG. 1, it may also be introduced into the catalyst treatment unit 10 through the pipe 8 together with the exhaust gas (pipe 6) from the detector 5 described later.

[0016] The sample or the like introduced from the vaporization chamber 2, which is the sample introduction unit, into the column 4 is separated for each component contained in the sample when passing through the column, and reaches the detector 5, which is the detection unit. In order to stabilize or promote the separation performance, the column 4 is held in an oven (also referred to as a "column oven") 3 capable of temperature control and maintained in a constant temperature state or a high temperature state.

[0017] The gas discharged from the column 4 is identified and quantified for the sample components by the detector 5. As the detector 5, various detectors such as the thermal conductivity detector shown in Patent Document 2, the flame ionization detector, and the dielectric barrier discharge ionization detector are used. In the thermal conductivity detector, the difference in the thermal conductivity of the compound compared with the reference gas (for example, the carrier gas) is detected. The sample and the carrier gas are heated by the filament element to a high temperature state. The gas containing the sample and the carrier gas is discharged from the detector 5 and introduced into the catalyst treatment chamber 10 through the pipes 6 and 8. When the detector requires a reference gas, a reference gas supply pipe (not shown) is connected to the detector 5.

[0018] The gas containing the carrier gas (hydrogen) discharged from the vaporization chamber 2 and the detector 5 is passed through a filter 9 that removes moisture, organic substances, and impurities in the gas, or a gas pretreated by other impurity removal methods is introduced before being introduced into the catalyst treatment unit 10.

[0019] In the catalyst treatment unit 10, the gas containing the carrier gas introduced from the pipe 8 is mixed with the air (gas containing oxygen) introduced from the pump 11 and brought into contact with a catalyst that oxidizes hydrogen. The catalyst is used by adhering to the surface of a structure having air permeability such as a mesh shape. As the catalyst material, any material that can oxidize hydrogen can be used. As a typical example, platinum (Pt) is used, but other substances can also be used. Through the oxidation reaction by the catalyst, hydrogen is converted into water (water vapor) and released outside the device (into the atmosphere).

[0020] For introducing an air source (oxygen source) into the catalyst treatment unit 10, not only can air be introduced using the pump 11, but it can also be introduced using a gas cylinder, a compressor, or the like. Also, instead of air, a gas supply source containing oxygen, for example, pure oxygen, may be introduced into the catalyst treatment unit 10. Further, without using a pump, a gas cylinder, a compressor, etc., for example, a gas containing oxygen may be supplied to the catalyst treatment unit 10 by gas diffusion.

[0021] In the catalyst treatment unit 10, the catalyst may be used at room temperature, or the temperature may be adjusted using a heater or the like, or it may be used after cooling using a fan or the like. For example, when platinum is used as the catalyst, it is possible to enhance the catalyst activity by using it in a temperature environment of several hundred degrees (°C). Also, by arranging the catalyst in such a high-temperature environment, adsorption of impurities that deteriorate the catalyst can be suppressed, leading to an extended lifespan of the catalyst.

[0022] As a heat source for heating the catalyst in the catalyst treatment unit, it is possible to use a dedicated heater for the catalyst treatment unit. However, as shown in FIG. 2, it is also possible to utilize the heat sources used in members other than the catalyst treatment unit (vaporization chamber 2, column oven 3, detector 5). A part (h1~h3) of the heat quantity supplied by these heat sources is used for heating the catalyst treatment unit 10. Also, it is possible to supply a part (h4) of the heat quantity from a member other than the gas chromatograph to the catalyst treatment unit 10. Naturally, it is also possible to use the surplus heat quantity (h20, h22) of the column oven 3 for the vaporization chamber 2 or the detector 5.

[0023] For example, the catalyst processing unit 10 can be positioned in close proximity to or in contact with heat sources such as the vaporization chamber 2, oven 3, and detector 5. Alternatively, the holding member that holds the vaporization chamber 2, etc., can be made of a material with high thermal conductivity, and the catalyst processing unit 10 can be positioned on the same holding member. Furthermore, by placing the catalyst processing unit 10 on the top plate of the gas chromatograph's main case, safety and space saving can be achieved. In addition, the top plate is heated by the heat from the oven 3, and the heat is transferred to the catalyst processing unit, thus reducing the power consumption required to heat the catalyst processing unit. On the other hand, while it is conceivable to place the catalyst processing unit inside the oven, this is not preferable because the inside of the oven is a sealed space, and if hydrogen gas were to leak, the hydrogen concentration would rise, which would be dangerous.

[0024] In a gas chromatograph, the column oven 3, vaporization chamber 2, detector 5, etc., are not left exposed but are covered by a housing CA, as shown in Figure 3. This housing CA prevents heat from easily escaping from the inside and also prevents operators from directly coming into contact with the high-temperature column oven, etc.

[0025] By placing the catalyst processing unit 10 inside the enclosure surrounding the column oven 3, it becomes possible to efficiently supply the heat released from the column oven to the catalyst processing unit 10. Furthermore, by directly placing the catalyst processing unit 10 on the top plate of the column oven 3, heat transfer from the column oven 3 to the catalyst processing unit 10 can be made even more efficient.

[0026] By placing not only the catalyst processing unit 10 but also other high-temperature components such as the vaporization chamber 2 and detector 5 on the top plate of the column oven 3, the heat transfer efficiency between adjacent components can be improved. Furthermore, by gathering the high-temperature components in one place, the opportunities for operators to come into contact with each component are significantly reduced compared to when these components are placed separately, thereby increasing safety. In addition, since the vaporization chamber 2 and detector 5 are connected to the catalyst processing unit 10 by piping, placing each component in close proximity allows for more compact piping and reduces the amount of carrier gas remaining in the piping.

[0027] As shown in Figure 4, a hydrogen detection sensor (HS) can be installed in a part of the discharge channel of the processed gas of the catalyst processing unit 10 to detect whether or not untreated hydrogen gas remains in the gas processed by the catalyst processing unit 10, or to detect its residual concentration. Using this detection result, the control means CU can also control the carrier gas (CG) piping valve (GV) to shut off the supply of carrier gas (hydrogen) if hydrogen gas remains.

[0028] The control means CU may be linked to the carrier gas supply of the gas chromatograph and a system may be constructed to constantly monitor the hydrogen concentration discharged from the catalyst processing unit 10. If a dangerous situation arises where hydrogen is not converted to water (water vapor) due to reasons such as decreased catalyst activity and is released into the atmosphere, the carrier gas can be immediately stopped, thereby further enhancing safety.

[0029] The above description of the gas chromatograph of the present invention is merely one example of an embodiment, and it is clear that any modifications, additions, or alterations made as appropriate within the spirit of the present invention will still fall within the technical scope of the present invention. Furthermore, it will be understood by those skilled in the art that the exemplary embodiments described above are specific examples of the following embodiments.

[0030] (Section 1) A gas chromatograph includes a sample introduction unit for introducing a vaporized sample together with a carrier gas into a separation column, and a detection unit for detecting the gas discharged from the separation column, and further includes a catalyst section equipped with a catalyst that introduces the gas containing the carrier gas discharged from the sample introduction unit or the detection unit and oxidizes the hydrogen gas.

[0031] Since hydrogen gas is converted to water in the catalytic section, equipment such as tubes and piping for discharging hydrogen gas is unnecessary, which also reduces limitations on the installation location of the gas chromatograph and suppresses deterioration of analytical performance due to vibration noise.

[0032] (Section 2) In the gas chromatograph described in paragraph 1 above, the carrier gas is hydrogen.

[0033] The chromatograph of the present invention is particularly suitable for use when hydrogen is used as the carrier gas. Furthermore, it is possible to easily avoid dangerous situations such as the explosion of hydrogen gas.

[0034] (Section 3) In the gas chromatograph described in paragraph 1 or paragraph 2 above, a gas containing oxygen is supplied to the catalyst processing unit.

[0035] By bringing exhaust gas containing hydrogen (carrier gas) and a gas containing oxygen into contact with a catalyst, the gas can be efficiently converted into water.

[0036] (Section 4) In the gas chromatograph described in any of paragraphs 1 to 3 above, the catalyst processing unit has means for heating or cooling the catalyst.

[0037] By placing the catalyst in an optimal temperature environment, it is possible to maximize its activity. Furthermore, when the catalyst is placed in a high-temperature environment, the adsorption of impurities that degrade the catalyst can be suppressed, leading to a longer catalyst lifespan.

[0038] (Section 5) In the gas chromatograph described in item 4 above, a heat source is provided for use in components other than the catalyst processing unit, and a portion of the heat supplied by the heat source is used for heating the catalyst processing unit.

[0039] This reduces the power consumption required to heat the catalyst in the catalyst processing unit.

[0040] (Section 6) In the gas chromatograph described in item 5 above, the heat source includes a column oven for heating the separation column, and the catalyst processing unit is located within a housing surrounding the column oven.

[0041] The enclosure surrounding the column oven allows for efficient transfer of the heat released by the column oven to the catalyst processing unit. Furthermore, it prevents operators from coming into contact with high-temperature components such as the column oven and catalyst processing unit.

[0042] (Section 7) In the gas chromatograph described in item 6 above, the catalyst processing unit and other heat sources other than the column oven are arranged in one place on the top plate of the column oven.

[0043] By consolidating heat source components such as the vaporization chamber and detectors onto the top plate of the column oven, not only is the heat transfer efficiency between each component increased, but the risk of operators coming into contact with each component is avoided compared to when the components are scattered around, thus improving safety.

[0044] (Section 8) In the gas chromatograph described in any of paragraphs 1 to 7 above, a filter is provided to remove at least a portion of components other than the carrier gas from the gas before the gas containing the carrier gas introduced into the catalyst processing unit comes into contact with the catalyst.

[0045] By installing a filter before the catalyst processing unit, the degradation of the catalyst due to organic matter and impurities is prevented, thereby extending the catalyst's lifespan.

[0046] (Section 9) The gas chromatograph described in any of paragraphs 1 to 8 above includes a carrier gas detection means for detecting the carrier gas from the gas discharged from the catalyst processing unit, and a control means for stopping the supply of the carrier gas to the gas chromatograph when the carrier gas detection means detects the carrier gas.

[0047] Even if the catalyst activity decreases and hydrogen is released outside the caschromatograph system, a system can be built that automatically shuts off the carrier gas (hydrogen) immediately if the situation becomes dangerous by constantly monitoring the signal from the hydrogen detection sensor with a control device, thereby achieving a higher level of safety. [Explanation of symbols]

[0048] 1. Sample inlet (injector) 2. Sample vaporization chamber 3-column oven 4 Separation columns 5 detectors 6-8 Piping (flow path) 9 filters 10 Catalyst Processing Unit 11 pumps CU control means HS Hydrogen Detection Sensor GV Gas Valve CG carrier gas CA cabinet

Claims

1. A gas chromatograph including a sample introduction unit for introducing a vaporized sample into a separation column together with a carrier gas, and a detection unit for detecting the gas discharged from the separation column, A gas chromatograph having a catalytic processing unit equipped with a catalyst that introduces a gas containing the carrier gas discharged from the sample introduction unit and a gas containing the carrier gas discharged from the detection unit, and oxidizes hydrogen gas.

2. A gas chromatograph according to claim 1, wherein the carrier gas is hydrogen.

3. A gas chromatograph according to claim 1, wherein a gas containing oxygen is supplied to the catalyst processing unit.

4. A gas chromatograph according to claim 1, wherein the catalyst processing unit has means for heating or cooling the catalyst.

5. A gas chromatograph according to claim 4, comprising a heat source used for components other than the catalyst processing unit, wherein a portion of the heat supplied by the heat source is used to heat the catalyst processing unit.

6. A gas chromatograph according to claim 5, wherein the heat source includes a column oven for heating the separation column, and the catalyst processing unit is arranged in a housing surrounding the column oven.

7. A gas chromatograph according to claim 6, wherein the catalyst processing unit and other heat sources other than the column oven are arranged in one place on the top plate of the column oven.

8. A gas chromatograph according to claim 1, comprising a filter that removes at least a portion of components other than the carrier gas from the gas before the gas containing the carrier gas introduced into the catalyst processing unit comes into contact with the catalyst.

9. A gas chromatograph according to claim 1, comprising a carrier gas detection means for detecting the carrier gas from the gas discharged from the catalyst processing unit, and a control means for stopping the supply of the carrier gas to the gas chromatograph when the carrier gas detection means detects the carrier gas.

Images