Achieving low concentration CO x FID device and method for methanogenic conversion and detection

Abstract

The present invention discloses an FID device and method for realizing low-concentration CO x methanation conversion and detection. The device includes a nozzle housing, a nozzle inner channel, a catalytic bed layer, a quartz wool layer, and a chromatographic column. The nozzle inner channel penetrates the nozzle housing along the height direction of the nozzle housing and includes an upper section, a middle section, and a lower section that are connected in sequence from top to bottom. The inner diameter of the upper section < the inner diameter of the middle section < the inner diameter of the lower section, and the inner diameter at the connection of the middle section with the upper section and the lower section gradually increases from top to bottom; the catalytic bed layer and the quartz wool layer are arranged in the middle section. The Ni-based catalyst of the catalytic bed layer includes metallic Ni and metal oxides; the quartz wool layer includes an upper quartz wool layer and a lower quartz wool layer. The CO x gas outlet end of the chromatographic column passes through the lower section of the nozzle inner channel and abuts against the lower quartz wool layer, and a gas channel is formed between the chromatographic column and the nozzle inner channel. The device can realize the detection of low-concentration CO x without additional heating, temperature control, heat preservation equipment, conversion chamber, and gas pipeline, and has high detection accuracy, high accuracy, and good reliability.

Description

Technical Field

[0001] The present invention belongs to the field of detection and analysis, and in particular, relates to realizing low concentration CO x FID device and method for methanation conversion and detection. Background Art

[0002] In scientific research and industrial production, it is often necessary to x The commonly used detector is gas chromatography, but the TCD detector cannot produce signals for trace components, and the FID detector (i.e. flame ionization detector) has high sensitivity, but it can only detect ionized organic matter and cannot detect CO x There is no response. Therefore, if the existing technology uses FID detector to detect trace CO x , usually by catalytic means, CO x Reduced to CH4, CO can be analyzed below ppm level x .

[0003] The most common device for the catalytic process is a methane converter. The common converter has a U-shaped or straight tube shape. A heating block and a temperature controller are used to heat and control the temperature of the converter respectively. The operating temperature is 350-380°C. Quartz wool and other materials are used as insulation materials on the outside. An additional hydrogenation pipeline is required to provide the H2 required for methanation. However, the structure of this type of methane converter is relatively complex and inconvenient to install and maintain. On this basis, a variety of improved versions of methane converters have appeared in recent years, such as a methane converter for the column head of a gas chromatograph. The device is provided with an insulation box, a heating chamber is arranged in the insulation box, and the heating chamber is a conversion chamber. The catalytic tube adopts a vertical structure and can be directly connected to the chromatographic column in the chromatographic column chamber, which greatly reduces the dead volume of the airflow and improves the conversion efficiency. In addition, there is also a trace CO for FID detector. x Analytical gas chromatography packed column, fill one end of the stainless steel column tube with hydrogenation catalyst, use H2 as carrier gas to achieve trace CO x However, in various types of methane reformers, the commonly used catalyst is a Ni-based supported catalyst, which can only show high activity at around 400°C, while the setting temperature of the FID detector is usually between 200 and 350°C, requiring additional heating, temperature control and insulation equipment. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one object of the present invention is to propose a method for realizing low concentration CO xFID device and method for methanogenic conversion and detection. The device integrates the methane converter and the FID detector by simply modifying the nozzle of the FID detector. It does not require additional heating, temperature control and insulation equipment, nor does it require additional conversion chambers and gas pipelines to achieve low-concentration CO x The detection not only reduces the energy consumption and device space of the equipment, directly enhances the multifunctional characteristics of gas chromatography, but also has the advantages of high detection precision, high accuracy and good reliability, and has broad application prospects.

[0005] In one aspect of the present invention, the present invention provides a method for achieving low concentration CO x FID device for methanogenic conversion and detection. According to an embodiment of the present invention, the device comprises:

[0006] Nozzle housing;

[0007] a nozzle inner channel, the nozzle inner channel penetrates the nozzle housing along the height direction of the nozzle housing, the nozzle inner channel comprises an upper section, a middle section and a lower section which are sequentially connected from top to bottom, the inner diameter of the upper section is smaller than the inner diameter of the middle section, the inner diameter of the middle section is smaller than the inner diameter of the lower section, the inner diameter of the connection between the upper section and the middle section gradually increases from top to bottom, and the inner diameter of the connection between the middle section and the lower section gradually increases from top to bottom;

[0008] A catalytic bed, the catalytic bed is arranged in the middle section of the inner channel of the nozzle, the catalytic bed comprises a Ni-based catalyst, and the Ni-based catalyst comprises metal Ni and a metal oxide;

[0009] A quartz wool layer, the quartz wool layer is arranged in the middle section of the inner channel of the nozzle, and the quartz wool layer comprises an upper quartz wool layer and a lower quartz wool layer for fixing the catalytic bed layer;

[0010] Chromatographic column, the chromatographic column CO x The gas outlet end passes through the lower section of the nozzle inner channel and stops at the lower quartz wool layer, and a gas channel is formed between the chromatographic column and the nozzle inner channel.

[0011] The present invention of the above embodiment of the present invention has low concentration CO x The FID device for methanation conversion and detection is a simple modification of the nozzle of the FID detector, and uses a Ni-based catalyst with high activity at low temperatures (such as <350°C or 250°C), so that the temperature of the detector itself can provide heat for the methane conversion process. Therefore, no additional heating, temperature control and insulation equipment is required, and no additional conversion chamber and gas pipeline are required to integrate the methane converter and the FID detector. At this time, the low-concentration CO xThe carrier gas can be mixed with H2 (and tail gas) at the outlet of the chromatographic column and then pass through the catalytic bed section to complete CO at the FID detection set temperature (such as 200-350℃). x Methanation conversion and detection of CO x The methanogenic conversion rate is high, for example, it can reach a conversion rate of not less than 98%. In summary, the FID device integrates the methane reformer and the FID detector, which not only reduces the energy consumption and device space of the equipment, but also directly enhances the multifunctional characteristics of the gas chromatography. It can also better achieve low concentration (such as 2-10000ppm) CO without changing the size and use conditions of the FID detector. x It can detect and has the advantages of high detection precision, high accuracy and good reliability, and has broad application prospects.

[0012] In addition, according to the above-mentioned embodiment of the present invention, the low concentration CO x The FID device for methanogenic conversion and detection may also have the following additional technical features:

[0013] In some embodiments of the present invention, the upper portion of the nozzle housing is in the shape of a cone, a pyramid, an inner curved surface cone, or an outer curved surface cone.

[0014] In some embodiments of the present invention, in the Ni-based catalyst, the content of the metal oxide is 10-60 wt %.

[0015] In some embodiments of the present invention, the Ni-based catalyst includes metal Ni and a metal oxide carrier, the metal oxide carrier includes at least one selected from Al2O3, SiO2, CeO2, La2O3, Eu2O3, ZrO2, and Sm2O3, and the mass ratio of the metal Ni to the metal oxide carrier is (40~90): (10~60).

[0016] In some embodiments of the present invention, the particle size of the catalyst used in the catalytic bed is 40-200 meshes.

[0017] In some embodiments of the present invention, the thickness of the catalytic bed layer is 5 to 40 mm, and the thickness of the upper quartz wool layer and the lower quartz wool layer are independently 0.5 to 3 mm.

[0018] In some embodiments of the present invention, the chromatographic column is a capillary column or a packed column.

[0019] In some embodiments of the present invention, in the nozzle inner channel, the inner diameter of the upper section is 0.1-3 mm, and the length is 1-20 mm; the inner diameter of the middle section is 1-6 mm, and the length is 6-30 mm; the inner diameter of the lower section is 2-10 mm, and the length is 10-80 mm.

[0020] In some embodiments of the present invention, the lower middle portion of the nozzle housing is detachably connected to a base, and the base is disposed below the nozzle housing.

[0021] In some embodiments of the present invention, the nozzle housing is connected to the base via threads.

[0022] In some embodiments of the present invention, the nozzle housing further comprises an insulating transition layer, which is disposed above a connection position between the nozzle housing and the base and separates the nozzle housing into two parts which are not connected to each other.

[0023] According to another aspect of the present invention, the present invention proposes a method for realizing low-concentration COx methanation conversion and detection by using the above-mentioned FID device. x Methanation conversion and detection method. According to an embodiment of the present invention, the method comprises:

[0024] (1) Carrying CO x The gas to be detected flows out of the chromatographic column and enters the catalytic bed layer, so that H2 enters the catalytic bed layer from the gas channel;

[0025] (2) Make the CO in the gas to be detected x reacting with H2 at the operating temperature of the catalyst bed and the FID detector to produce CH4 and H2O;

[0026] (3) allowing the chromatographic column carrier gas, H2 and CH4 to flow out of the catalytic bed layer and merge into one channel in the upper section of the nozzle inner channel and flow out through the nozzle opening;

[0027] (4) The air meets the H2 flowing out of the nozzle above the nozzle, forming a hydrogen flame ionization zone. The hydrocarbons are ionized in the flame zone to form positive ions, which are collected and moved under the action of the negative electrostatic field to form a weak current. The weak current is amplified by the electrometer to form a detection signal. The detected CH4 content is obtained based on the detection signal, so as to infer the CO content in the gas to be detected. x The content value.

[0028] The above embodiment of the present invention realizes low concentration CO x The method of methanation conversion and detection can directly use the temperature of the detector itself to provide heat for the methane conversion process, without the need for additional heating, temperature control and insulation equipment, and without the need for additional conversion chambers and gas pipelines. It is not only simple in process, but also low in energy consumption, CO x The methanogenic conversion rate is high (e.g., it can reach a conversion rate of not less than 98%), and it also has the advantages of high detection precision, high accuracy and good reliability, and can better achieve low concentration (e.g., 2-10000ppm) CO x The detection has broad application prospects.

[0029] In some embodiments of the present invention, before performing step (1), a chromatographic column is used to separate the component to be detected, CO, from the sample gas. x , and obtain the gas to be detected.

[0030] In some embodiments of the present invention, in step (1), the carrier gas used in the chromatographic column is at least one selected from high-purity Ar, high-purity He, high-purity N2 and high-purity H2.

[0031] In some embodiments of the present invention, in step (1), the flow rate of the carrier gas is 2-50 ml / min, the flow rate of H2 flowing into the gas channel is 20-40 ml / min, and the volume ratio of H2 to the carrier gas is 0.4-50.

[0032] In some embodiments of the present invention, in step (1), the flow rate of the carrier gas is 2-50 ml / min, the flow rate of H2 is 20-40 ml / min, and the volume ratio of H2 to the carrier gas is 0.4-50.

[0033] In some embodiments of the present invention, in step (1), H2 and tail gas are allowed to enter the catalytic bed from the gas channel, and the flow rate of the tail gas is 10 to 30 ml / min.

[0034] In some embodiments of the present invention, in step (3), the flow rate of the air is 200-400 ml / min.

[0035] In some embodiments of the present invention, in step (2), the operating temperature of the FID detector is 200-350°C.

[0036] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0038] Figure 1 This is a method for realizing low concentration CO according to an embodiment of the present invention. x Schematic diagram of the FID device structure for methanation conversion and detection.

[0039] Figure 2 1 is a top view of the lower section of the inner channel of the nozzle according to one embodiment of the present invention.

[0040] Figure 3 This is a method for realizing low concentration CO according to an embodiment of the present invention. xFlow chart of the method for methanogenic conversion and detection. DETAILED DESCRIPTION

[0041] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0042] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "length", "thickness", "upper", "lower", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly specified. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the present invention, unless otherwise clearly specified and limited, the first feature "upper" or "lower" of the second feature can be the first and second features directly contacting, or the first and second features indirectly contacting through an intermediate medium. Moreover, the first feature being “above”, “above”, and “above” the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being “below”, “below”, and “below” the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0043] In one aspect of the present invention, the present invention provides a method for achieving low concentration CO x FID device for methanogenic conversion and detection. According to an embodiment of the present invention, reference Figure 1 It is understood that the device includes: a nozzle housing 10, a nozzle inner channel 20, a catalytic bed 30, a quartz wool layer 40 and a chromatographic column 50. The device integrates the methane reformer and the FID detector by simply modifying the nozzle of the FID detector. It does not require additional heating, temperature control and insulation equipment, nor does it require additional reforming chambers and gas pipelines to achieve low-concentration CO xThe detection not only reduces the energy consumption and space of the equipment, directly enhances the multifunctional characteristics of gas chromatography, but also has the advantages of high detection precision, high accuracy and good reliability, and has broad application prospects. Figures 1-2 The above embodiment of the present invention realizes low concentration CO x The FID device for methanation conversion and detection is described in detail.

[0044] Nozzle housing 10

[0045] According to an embodiment of the present invention, the upper structure of the nozzle housing 10 can be a cone, a pyramid, an inner arc cone or an outer arc cone, etc. This structure is more conducive to CO x The methane obtained by the reaction is mixed with air and burned at the nozzle mouth to realize the detection of CH4 content by FID detector, thereby indirectly obtaining CO in the gas to be detected. x The content value.

[0046] According to an embodiment of the present invention, the middle and lower part of the nozzle housing 10 can be detachably connected to a base (not shown), wherein the base can be disposed below the nozzle housing 10 for fixing the nozzle through the nozzle housing. It is understandable that the connection method between the nozzle housing 10 and the base is not particularly limited, and those skilled in the art can select it according to actual needs, as long as the nozzle housing can be detachably fixed. For example, the nozzle housing 10 and the base can be connected by threads.

[0047] According to the embodiment of the present invention, the material of the nozzle housing 10 is not particularly limited, and those skilled in the art can select it according to actual needs. For example, the material of the nozzle housing 10 can be stainless steel, quartz, ceramic or platinum. Figure 2 It is understood that when the nozzle housing 10 is not grounded and the nozzle is made of metal, the nozzle housing 10 may further include an insulating transition layer 70, wherein the insulating transition layer 70 may be disposed above the connection position 11 between the nozzle housing 10 and the base and separate the nozzle housing 10 into two parts that are not connected to each other (connected at intervals) from top to bottom, thereby avoiding the formation of a conductive path between the housing part close to the nozzle mouth and the housing part away from the nozzle mouth.

[0048] Nozzle inner channel 20

[0049] According to the embodiments of the present application, reference Figure 1It is understood that the nozzle inner channel 20 penetrates the nozzle housing 10 along the height direction of the nozzle housing 10, and the nozzle inner channel 20 includes an upper section 21, a middle section 22 and a lower section 23 which are connected in sequence from top to bottom. The inner diameter of the upper section 21 is smaller than the inner diameter of the middle section 22, and the inner diameter of the middle section 22 is smaller than the inner diameter of the lower section 23. The inner diameter of the connection 24 between the upper section 21 and the middle section 22 gradually increases from top to bottom, and the inner diameter of the connection 25 between the middle section 22 and the lower section 23 gradually increases from top to bottom. The inventors have found that by adopting the above-mentioned nozzle inner channel which gradually narrows from bottom to top, not only can the fluidity of the airflow be improved, and the formation of a dead zone at the connection between two adjacent sections can be avoided, but also the installation of the catalytic bed can be facilitated. Therefore, not only is the operation convenient, but also the problem of inaccurate detected methane content caused by the airflow staying in the dead zone (the amount of stay is unknown), which further affects the detection accuracy and reliability, can be avoided. It should be noted that the lower section 23 of the nozzle inner channel 20 is used to supply the separated CO through the gas chromatography column. x , where CO x The middle section 22 is used to realize CO x The upper section 21 is used to supply the methanogenic product to the nozzle for mixing with air for combustion.

[0050] According to an embodiment of the present application, in the nozzle inner channel 20, the inner diameter of the upper section 21 can be 0.1 to 3 mm (for example, 0.5 mm, 1 mm, 2 mm or 3 mm, etc.), and the length can be 1 to 20 mm (for example, 4 mm, 8 mm, 12 mm or 16 mm, etc.); the inner diameter of the middle section 22 can be 1 to 6 mm (for example, 2 mm, 3 mm, 4 mm or 5 mm, etc.), and the length can be 6 to 30 mm (for example, 10 mm, 14 mm, 18 mm, 22 mm or 26 mm, etc.); the lower section 2 The inner diameter of the upper section 21 can be 2 to 10 mm (for example, 4 mm, 6 mm or 8 mm), and the length can be 10 to 80 mm (for example, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm or 70 mm), as long as the inner diameter of the upper section 21 is less than the inner diameter of the middle section 22 and less than the inner diameter of the lower section 23; in addition, compared with the lower section 23, the length of the middle section 22 and the upper section 21 has a greater impact on the detection result. The length of the middle section 22 can be comprehensively considered based on the type, efficiency, service life, and CO content of the gas to be detected. x The concentration of the catalyst, the fixing effect of the quartz wool layer on the catalyst, the inner diameter of the middle section, etc. can be flexibly selected. For example, the length of the upper section 21 can be made less than the length of the middle section 22 and less than the length of the lower section 23. This can not only make the directional flow of the gas flow better, but also provide a better gas chromatography column for separating CO x , and CO x The catalytic methanation reaction with H2 provides sufficient time to ensure that as much CO as possible xCan be converted into CH4, thereby further improving the accuracy and reliability of the detection results.

[0051] According to the embodiment of the present application, the nozzle inner channel 20 can be formed by a hollow nozzle shell body, or by a separate pipe inserted and fixed in the middle of the nozzle shell. When the nozzle inner channel 20 is a separate pipe, its material can be the same as that of the nozzle shell 10, or different, and can be selected from stainless steel, quartz, ceramic or platinum. Preferably, the material of the nozzle inner channel 20 can be the same as that of the nozzle shell 10, which is more conducive to the transfer of heat from the nozzle shell to the nozzle inner channel, so that the catalyst has a higher catalytic activity at the working temperature of the FID detector, and the CO x The full methanation improves the accuracy and reliability of the test results, and is also beneficial to maintaining the consistency of the thermal expansion coefficients of the nozzle inner channel and the nozzle shell, making the two better in structural stability during use.

[0052] Catalytic bed 30

[0053] According to the embodiments of the present application, reference Figure 1 It is understood that the catalytic bed 30 is arranged in the middle section 22 of the nozzle inner channel 20, and the catalytic bed 30 includes a Ni-based catalyst, and the Ni-based catalyst includes a metal oxide. The inventors found that the commonly used Ni-based supported catalyst usually exhibits a high activity at around 400°C, and an additional methane converter needs to be set and the operating temperature needs to be set at 380-450°C, that is, the methane converter needs heating, temperature control and insulation equipment to achieve CO x The new Ni-based catalyst can obtain high catalytic activity and methane selectivity at a lower temperature (such as <350°C or 250°C). Therefore, by using this catalyst to form a catalytic bed, no additional heating, temperature control and insulation equipment is required. Only a simple modification of the nozzle of the FID detector is required, and the temperature of the detector itself can be used to provide heat for the methane conversion process to achieve CO x The existing methane reformer can be discarded to achieve full methanation, which effectively reduces equipment energy consumption and device space while ensuring the accuracy and reliability of the test results.

[0054] According to the embodiments of the present application, the content of the metal oxide in the Ni-based catalyst may be 10 to 60 wt%, for example, 25 wt%, 35 wt% or 45 wt%, etc. The inventors have found that if the content of the metal oxide is too low, the catalytic activity of the Ni-based catalyst at the working temperature of the FID detector is still not ideal, and if the content of the metal oxide is too high, the catalyst cost will be significantly increased. In the present invention, by controlling the content of the metal oxide to be within the above range, not only the raw material cost can be guaranteed, but also the Ni-based catalyst can be more suitable for catalyzing CO at low temperatures. x Hydromethanation reaction, for example, can achieve more than 98% CO x conversion rate and 100% CH4 selectivity, and has good catalytic stability.

[0055] According to the embodiments of the present application, the Ni-based catalyst used in the present invention is a supported catalyst, including active metal Ni and a metal oxide carrier, wherein the metal oxide carrier may include at least one selected from Al2O3, SiO2, CeO2, La2O3, Eu2O3, ZrO2, Sm2O3, and the mass ratio of active metal Ni to metal oxide carrier may be (40-90): (10-60), for example, it may be 45 / 55, 40 / 60 or 50 / 50, etc., and for another example, the proportion of active metal in Ni-based catalyst may be 40-90wt%. It is understood that the carrier may include at least one metal oxide. The inventors found that the above-mentioned metal oxide carrier has a strong interaction with the active metal Ni, and can achieve uniform dispersion of the active metal Ni on the carrier, which is more conducive to improving the catalytic activity and catalytic stability of the Ni-based catalyst; in addition, by controlling the mass ratio of active metal Ni to metal oxide to the above range, it is also more conducive to ensuring the catalytic activity and methane selectivity of the Ni-based catalyst.

[0056] According to the embodiment of the present application, the particle size of the catalyst used in the catalytic bed 30 can be 40-200 meshes, for example, 40-50 meshes, 50-60 meshes, 80-100 meshes or 100-120 meshes, etc. The inventors have found that by controlling the catalyst to be within the above-mentioned range, it is not only more conducive to processing and granulation, but also can make the catalytic bed have a suitable compaction density, so that CO x The contact reaction time with H2 in the catalytic bed is sufficient to achieve CO x The full methanation can also achieve effective airflow, so that the reaction gas can flow smoothly to the nozzle to mix with the air for combustion, and then the CH4 content can be detected by FID detector during the combustion process, and the CO content in the gas to be detected can be indirectly obtained. x The content value.

[0057] According to the embodiment of the present application, the thickness of the catalyst bed 30 can be 5 to 40 mm, for example, 8 mm, 10 mm, 15 mm, 25 mm or 35 mm. The inventors found that if the thickness of the catalyst bed is too small, it is difficult to ensure that CO x In the process of flowing through the catalytic bed, full methanation is achieved. If the thickness of the catalytic bed is too large, the airflow will stay in the catalytic bed for too long, affecting the detection efficiency and increasing the cost of raw materials. Based on the selection of catalyst, particle size, and the inner diameter and length of the nozzle channel, the catalytic bed can be controlled within the above thickness range to ensure CO x On the basis of full methanation (conversion rate>98%), the detection efficiency is improved and the raw material cost is reduced, so as to achieve high accuracy and reliability of the detection results.

[0058] Quartz wool layer 40

[0059] According to an embodiment of the present invention, referring to Figure 1 It is understood that the quartz wool layer 40 is arranged in the middle section 22 of the nozzle inner channel 20. The quartz wool layer 40 includes an upper quartz wool layer 41 and a lower quartz wool layer 42 for fixing the catalytic bed 30, thereby not affecting the permeability of the airflow, and can also achieve effective fixation of the catalytic bed.

[0060] According to an embodiment of the present application, based on a catalytic bed layer with a thickness of 5 to 40 mm, the thickness of the upper quartz wool layer 41 and the lower quartz wool layer 42 can be independently 0.5 to 3 mm, for example, can be independently 1 mm, 2 mm or 2.5 mm, etc., thereby providing a sufficiently large fixing strength for the catalytic bed layer to ensure the structural stability of the fixed catalytic bed layer, and avoiding the flow rate and detection efficiency of the airflow being affected by the excessive thickness of the quartz wool layer.

[0061] Chromatographic column 50

[0062] According to an embodiment of the present invention, referring to Figure 1 Understand that the CO at column 50 x The gas outlet end 51 passes through the lower section 23 of the nozzle inner channel 20 and stops at the lower quartz wool layer 42. A gas channel 60 is formed between the chromatographic column 50 and the nozzle inner channel 20. x The gas to be detected flows out of the chromatographic column through the quartz wool layer into the catalytic bed layer, so that H2 (or H2 and tail gas) enters the catalytic bed layer from the gas channel through the quartz wool layer. It can be understood that the chromatographic column 50 is a gas chromatographic column for separating CO from the sample gas. x Gas. It should be noted that due to different CO x The separation time is different, so different CO x The response time of the converted CH4 in the FID detector is different, and thus different COx concentration.

[0063] According to the embodiment of the present application, the chromatographic column 50 can be either a capillary column or a packed column. When a packed column is selected, H2 is only required to be supplied in the gas channel; when a capillary column is selected, tail gas needs to be introduced into the gas channel as a supplementary gas, thereby not only improving the column efficiency but also improving the sensitivity of the FID detector. In addition, the carrier gas used in the chromatographic column can be at least one selected from high-purity Ar, high-purity He, high-purity N2 and high-purity H2. It can be understood that the purity of high-purity Ar, high-purity He, high-purity N2 and high-purity H2 can be independently not less than 99.9% or 99.99%.

[0064] According to an embodiment of the present application, the flow rate of the carrier gas used in the chromatographic column can be 2-50 ml / min (for example, 10 ml / min, 20 ml / min, 30 ml / min or 40 ml / min, etc.), the flow rate of H2 flowing into the gas channel can be 20-40 ml / min (for example, 25 ml / min, 30 ml / min or 35 ml / min, etc.), and the volume ratio of H2 to the carrier gas can be 0.4-50, for example, 1, 5, 10, 20, 30 or 40, etc.; further, when the chromatographic column 50 uses a capillary column, H2 and the tail gas enter the catalytic bed from the gas channel, and the flow rate of the tail gas can be 10-30 ml / min (for example, 15 ml / min, 20 ml / min or 25 ml / min, etc.). The inventors found that controlling the above volume ratio and flow rate is not only more conducive to the directional flow of the gas flow, but also can ensure the sensitivity of the FID detector, and ensure the accuracy and reliability of the detection results.

[0065] According to an embodiment of the present application, when the chromatographic column carrier gas, H2 and CH4 flow out of the catalytic bed and mix with air at the nozzle mouth and burn, the air flow rate can be 200-400 ml / min, for example, 250 ml / min, 300 ml / min or 350 ml / min, etc., which can further ensure the sensitivity of the FID detector.

[0066] In summary, the present invention has a low concentration of CO x The FID device for methanation conversion and detection is a simple modification of the nozzle of the FID detector, and a Ni-based catalyst with high activity at low temperatures (such as <350°C or 250°C) is used, so that the temperature of the detector itself can provide heat for the methane conversion process. Therefore, no additional heating, temperature control and insulation equipment is required, and no additional conversion chamber and gas pipeline are required. The methane converter and FID detector can be integrated into one. At this time, the low-concentration CO xThe carrier gas can be mixed with H2 (and tail gas) at the outlet of the chromatographic column and then pass through the catalytic bed section to complete CO at the FID detection set temperature (such as 200-350℃). x Methanation conversion and detection of CO x The methanogenic conversion rate is high, for example, it can reach a conversion rate of not less than 98%. In summary, the FID device integrates the methane reformer and the FID detector, which not only reduces the energy consumption and device space of the equipment, but also directly enhances the multifunctional characteristics of the gas chromatography. It can also better achieve low concentration (such as 2-10000ppm) CO without changing the size and use conditions of the FID detector. x It can detect and has the advantages of high detection precision, high accuracy and good reliability, and has broad application prospects.

[0067] According to another aspect of the present invention, the present invention proposes a method for realizing low-concentration COx methanation conversion and detection by using the above-mentioned FID device. x Methanation conversion and detection method. According to an embodiment of the present invention, the method comprises:

[0068] S100: CO x The gas to be detected flows out of the chromatographic column and enters the catalytic bed layer, so that H2 enters the catalytic bed layer from the gas channel. According to an embodiment of the present invention, the gas chromatographic column is first used to separate the component to be detected CO from the sample gas. x , and then the CO x The gas to be detected flows out of the chromatographic column and enters the catalytic bed. The carrier gas used in the chromatographic column is at least one selected from high-purity Ar, high-purity He, high-purity N2 and high-purity H2; the flow rate of the carrier gas can be 2-50 ml / min, the flow rate of H2 flowing into the gas channel can be 20-40 ml / min, and the volume ratio of H2 to the carrier gas can be 0.4-50; further, when the chromatographic column is a capillary column, H2 and tail gas are allowed to enter the catalytic bed from the gas channel, and the flow rate of the tail gas can be 10-30 ml / min. It should be noted that the selection of the chromatographic column, the thickness of the catalytic bed, the selection of the catalyst and the above-mentioned related technical features have been described in detail in the previous section and will not be repeated here.

[0069] S200: Make the CO in the gas to be detected x The reaction between the catalyst bed and the FID detector is to generate CH4 and H2O. According to an embodiment of the present invention, the operating temperature of the FID detector is 200-350°C. x During the methanogenic conversion, the temperature of the detector itself alone can provide heat for the methane conversion process.

[0070] S300: After the chromatographic column carrier gas, H2 and CH4 flow out from the catalytic bed, they are combined into one channel in the upper section of the nozzle inner channel and flow out through the nozzle opening.

[0071] S400: The air is made to meet the H2 flowing out of the nozzle above the nozzle to form a hydrogen flame ionization zone. Hydrocarbons (such as CH4) will be ionized in the flame zone to form positive ions. Under the action of the negative electrostatic field, they are collected and moved to form a weak current. The weak current is amplified by the electrometer to form a detection signal. Based on the detection signal, the detected CH4 content is obtained to infer the CO content in the gas to be detected. x According to an embodiment of the present invention, the flow rate of air may be 200-400 ml / min, thereby further ensuring the sensitivity of the FID detector.

[0072] In summary, the above embodiments of the present invention can achieve low concentration CO x The method of methanation conversion and detection can directly use the temperature of the detector itself to provide heat for the methane conversion process, without the need for additional heating, temperature control and insulation equipment, and without the need for additional conversion chambers and gas pipelines. It is not only simple in process, but also low in energy consumption, CO x The methanogenic conversion rate is high (e.g., it can reach a conversion rate of not less than 98%), and it also has the advantages of high detection precision, high accuracy and good reliability, and can better achieve low concentration (e.g., 2-10000ppm) CO x It should be noted that for the above-mentioned low-concentration CO x The characteristics and effects described for the FID device for methanation conversion and detection are also applicable to the realization of low concentration CO x The methods of methanogenesis conversion and detection will not be described in detail here.

[0073] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0074] Example 1

[0075] This example uses the FID device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected x The concentration is usually lower than 0.1v%, and the product of catalytic conversion is CH4. In this embodiment, in order to calibrate CH4, a gas to be detected containing only 100ppm CH4 is provided, and the balance gas is Ar.

[0076] The devices used are as Figure 1 As shown, the chromatographic column uses a DB-WAX capillary column with a length of 30m, an outer diameter of 0.53mm, a column thickness of 0.25μm, and a quantitative loop volume of 250μl. This chromatographic column can separate CO, CO2 and CH4.

[0077] Combination of the gas flow path of the gas to be detected, H2 and the makeup gas Figure 2 It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, and H2 and the tail gas are introduced into the gas channel 60. High-purity Ar with hydrogen content is used as the carrier gas, the capillary column flow rate is 5ml / min, the H2 flow rate introduced into the gas channel is 20ml / min, and the tail gas flow rate is 25ml / min. Air flows in from the nozzle at a flow rate of 300ml / min.

[0078] In the inner channel of the nozzle, the inner diameter of the upper section is 0.5 mm and the length is 10 mm; the inner diameter of the middle section is 2 mm and the length is 15 mm; the inner diameter of the lower section is 2 mm and the length is 30 mm.

[0079] In this example, a Ni-based catalyst is used, the mass fraction of the active component Ni is 60%, and the carrier is a 1:1 mixture of CeO2 and Al2O3, the particle size of which is 40-60 mesh, filled in the nozzle channel. The FID detector is set to a temperature of 250°C and can remain unchanged for a long time. The catalytic bed is filled with a thickness of 10mm and is filled in the middle section of the nozzle channel. The upper and lower ends of the catalytic bed are filled with quartz wool layers, and the thickness of the quartz wool layers at both ends is 1.5mm.

[0080] The gas to be detected flows out of the capillary column and passes through the catalytic bed to obtain the CH4 response signal through the FID detector. The test results show that the retention time of CH4 in the FID spectrum is 1.053min, the peak area is 642915, and the peak area has a linear response relationship with the concentration.

[0081] Example 2

[0082] This example uses the device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected x The concentration is usually lower than 0.1v%, and the product of catalytic conversion is CH4. In this embodiment, in order to calibrate CH4, a gas to be detected containing only 1000ppm CH4 is provided, and the balance gas is Ar.

[0083] The devices used are as Figure 1 As shown, the chromatographic column is packed with HayeSep Q, with a length of 1.83m, an outer diameter of 1 / 8 inch, a column thickness of 2mm, and a quantitative loop volume of 1ml. This chromatographic column can separate CO, CO2 and CH4.

[0084] Combination of the gas to be tested, H2 and makeup gas flow paths Figure 2 It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, and H2 is introduced into the gas channel 60. High-purity H2 is used as the carrier gas, the flow rate of the filling column is 25 ml / min, and the flow rate of H2 introduced into the gas channel is 20 ml / min. Air flows in from the nozzle at a flow rate of 300 ml / min.

[0085] In the nozzle inner channel, the inner diameter of the upper section is 0.5mm and the length is 10mm; the inner diameter of the middle section is 2mm and the length is 15mm; the inner diameter of the lower section is 2mm and the length is 30mm. In this example, a Ni-based catalyst is used, the mass fraction of the active component Ni is 60%, and the carrier is a 1:1 mixture of CeO2 and Al2O3, the particle size is 40-60 mesh, and it is filled in the nozzle inner channel. The FID detector is set to a temperature of 250°C and can remain unchanged for a long time. The catalytic bed is filled with a thickness of 10mm and is filled in the middle section of the nozzle inner channel. The upper and lower ends of the catalytic bed are filled with quartz wool layers respectively, and the thickness of the quartz wool layers at both ends is 1.5mm.

[0086] The gas to be detected flows out of the packed column and passes through the catalytic bed to obtain the CH4 response signal through the FID detector. The test results show that the retention time of CH4 in the FID spectrum is 1.051min, the peak area is 6430126, and the peak area has a linear response relationship with the concentration.

[0087] Example 3

[0088] This example uses the device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected x The concentration is usually lower than 0.1v%. In this example, in order to verify the actual ability of the catalytic bed to convert trace amounts of CO, the CO volume concentration in the gas to be detected was 500ppm, and 500ppm CH4 was added as an internal standard, and the balance gas was Ar.

[0089] The devices used are as Figure 1 As shown, the chromatographic column uses a DB-WAX capillary column with a length of 30m, an outer diameter of 0.53mm, a column thickness of 0.25μm, and a quantitative loop volume of 250μl. This chromatographic column can separate CO and CH4.

[0090] Combination of the gas flow path of the gas to be detected, H2 and the makeup gas Figure 2It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, and H2 and the tail gas are introduced into the gas channel 60. High-purity Ar is used as the carrier gas, the capillary column flow rate is 5ml / min, the H2 flow rate introduced into the gas channel is 20ml / min, and the tail gas flow rate is 25ml / min. Air flows in from the nozzle at a flow rate of 300ml / min.

[0091] In the nozzle inner channel, the inner diameter of the upper section is 0.3mm and the length is 10mm; the inner diameter of the middle section is 1.5mm and the length is 20mm; the inner diameter of the lower section is 2mm and the length is 30mm. The CO flow rate entering the catalytic bed is 0.0025ml / min, and the ratio of H2 flow rate to CO flow rate is 8000:1. In this example, a Ni-based catalyst is used, the mass fraction of the active component Ni is 60%, and the carrier is a 1:1 mixture of La2O3 and Al2O3, the particle size is 100-120 mesh, and it is filled in the nozzle inner channel. The FID detector is set to a temperature of 300°C and can remain unchanged for a long time. It is inferred from the catalyst activity data that 14mg of catalyst needs to be filled to process the provided CO, so the thickness of the catalytic bed is 17mm, which is filled in the middle section of the nozzle inner channel. The upper and lower ends of the catalytic bed are filled with quartz wool layers, and the thickness of the quartz wool layers at both ends is 1.2mm.

[0092] After the gas to be detected flows out of the capillary column and passes through the catalytic bed, CO can be completely converted into CH4, and then the CH4 response signal is obtained through the FID detector, thereby obtaining the corresponding CO concentration information. The test results show that the retention time of CH4 converted from CO in the FID spectrum is 0.823min, and the peak area is 3166356. The retention time of the original (used for calibration) CH4 is 1.051min, and the peak area is 3214686. It can be calculated that this catalytic bed can achieve 98.5% conversion of CO and 100% CH4 selectivity. Through this device, the detection of trace CO can be achieved in an integrated manner.

[0093] Example 4

[0094] This example uses the device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected x The concentration is usually lower than 0.1v%. In this example, in order to verify the actual ability of the catalytic bed to convert trace amounts of CO, the CO volume concentration in the gas to be detected was 500ppm, and 500ppm CH4 was added as an internal standard, and the balance gas was Ar.

[0095] The devices used are as Figure 1As shown, the chromatographic column is packed with HayeSep Q, with a length of 1.83m, an outer diameter of 1 / 8 inch, a column thickness of 2mm, and a quantitative loop volume of 1ml. This chromatographic column can separate CO and CH4.

[0096] Combination of the gas to be detected and H2 gas flow path Figure 2 It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, and H2 is introduced into the gas channel 60. High-purity H2 is used as the carrier gas, the column flow rate is 20 ml / min, and the H2 flow rate introduced into the gas channel is 40 ml / min. Air flows in from the nozzle at a flow rate of 300 ml / min.

[0097] In the inner channel of the nozzle, the inner diameter of the upper section is 0.3 mm and the length is 10 mm; the inner diameter of the middle section is 1.5 mm and the length is 20 mm; the inner diameter of the lower section is 2 mm and the length is 30 mm.

[0098] The CO flow rate entering the catalyst bed is 0.01 ml / min, and the H2 flow rate is the same as CO x The flow ratio is 5999:1. In this example, a Ni-based catalyst is used, the mass fraction of the active component Ni is 80%, and the carrier is a 2:1 mixture of Al2O3 and CeO2, with a particle size of 60-80 mesh, which is filled in the nozzle channel. The FID detector is set to a temperature of 230°C and can remain unchanged for a long time. It is inferred from the catalyst activity data that 50 mg of catalyst is required to process the provided CO2, then the thickness of the catalytic bed is 10 mm, filled in the middle section of the nozzle channel, and the upper and lower ends of the catalytic bed are filled with quartz wool layers, and the thickness of the quartz wool layers at both ends is 1.5 mm.

[0099] After the detection gas flows out of the filling column and passes through the catalytic bed, CO can be completely converted into CH4, and then the CH4 response signal is obtained through the FID detector, thereby obtaining the corresponding CO concentration information. The test results show that the retention time of CH4 converted from CO in the FID spectrum is 0.821min, the peak area is 3170287, and the retention time of the original CH4 is 1.045min, and the peak area is 3215301. It can be calculated that this catalytic bed can achieve 98.6% conversion of CO and 100% CH4 selectivity. Through this device, trace CO detection can be achieved in an integrated manner.

[0100] Example 5

[0101] This example uses the device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected xThe concentration is usually lower than 0.1v%. In this example, in order to verify the actual ability of the catalytic bed to convert trace amounts of CO2, the CO2 volume concentration in the gas to be detected was 100ppm, and 100ppm CH4 was added as an internal standard, and the balance gas was Ar.

[0102] The devices used are as Figure 1 As shown, the chromatographic column 4 is a DB-WAX capillary column with a length of 30 m, an outer diameter of 0.53 mm, a column thickness of 0.25 μm, and a quantitative loop volume of 25 μl. This chromatographic column can separate CO2 and CH4.

[0103] Combination of the gas flow path of the gas to be detected, H2 and the makeup gas Figure 2 It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, and H2 and the tail gas are introduced into the gas channel 60. High-purity Ar is used as the carrier gas, the capillary column flow rate is 5ml / min, the H2 flow rate introduced into the gas channel is 25ml / min, and the tail gas flow rate is 30ml / min. The air flows in from the nozzle at a flow rate of 250ml / min.

[0104] In the inner channel of the nozzle, the inner diameter of the upper section is 0.7 mm and the length is 10 mm; the inner diameter of the middle section is 1 mm and the length is 15 mm; the inner diameter of the lower section is 2 mm and the length is 30 mm.

[0105] The CO2 flow rate entering the catalytic bed is 0.0005ml / min, and the ratio of H2 flow rate to CO2 flow rate is 50000:1. In this example, a Ni-based catalyst is used, the mass fraction of the active component Ni is 40%, and the carrier is a 1:4 mixture of Eu2O3 and Al2O3, with a particle size of 40-50 mesh, which is filled in the channel inside the nozzle. The FID detector is set to a temperature of 340°C and can remain unchanged for a long time. It is inferred from the catalyst activity data that 10mg of catalyst is required to process the provided CO2, so the thickness of the catalytic bed is 10mm, which is filled in the middle section of the channel inside the nozzle. The upper and lower ends of the catalytic bed are filled with quartz wool layers, and the thickness of the quartz wool layers at both ends is 1.5mm.

[0106] After the gas to be detected flows out of the capillary column and passes through the catalytic bed, CO2 can be completely converted into CH4, and then the CH4 response signal is obtained through the FID detector, thereby obtaining the corresponding CO2 concentration information. The test results show that the retention time of CH4 converted from CO2 in the FID spectrum is 3.019min, the peak area is 635336, and the retention time of the original CH4 is 1.051min, the peak area is 643053. It can be calculated that this catalytic bed can achieve 98.8% conversion of CO2 and 100% CH4 selectivity. Through this device, the detection of trace CO2 can be achieved in an integrated manner.

[0107] Example 6

[0108] This example uses the device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected x The concentration is usually lower than 0.1v%. In this embodiment, in order to verify the actual ability of the catalytic bed to convert trace amounts of CO2, the CO2 volume concentration in the gas to be detected was 200ppm, and 200ppm CH4 was added as an internal standard, and the balance gas was Ar.

[0109] The devices used are as Figure 1 As shown, the chromatographic column is packed with HayeSep Q, with a length of 1.83m, an outer diameter of 1 / 8 inch, a column thickness of 2mm, and a quantitative loop volume of 1ml. This chromatographic column can separate CO2 and CH4.

[0110] Combination of the gas to be detected and H2 gas flow path Figure 2 It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, and H2 is introduced into the gas channel 60. High-purity H2 is used as the carrier gas, the column flow rate is 20 ml / min, and the H2 flow rate introduced into the gas channel is 40 ml / min. Air flows in from the nozzle at a flow rate of 400 ml / min.

[0111] In the inner channel of the nozzle, the inner diameter of the upper section is 0.7 mm and the length is 10 mm; the inner diameter of the middle section is 1 mm and the length is 22 mm; the inner diameter of the lower section is 2 mm and the length is 30 mm.

[0112] The CO2 flow rate entering the catalytic bed is 0.004ml / min, and the ratio of H2 flow rate to CO2 flow rate is 14999:1. In this example, a Ni-based catalyst is used, the mass fraction of the active component Ni is 40%, and the carrier is a 3:2:1 mixture of Al2O3, CeO2 and Eu2O3, with a particle size of 60-80 mesh, which is filled in the channel inside the nozzle. The FID detector is set to a temperature of 250°C and can remain unchanged for a long time. It is inferred from the catalyst activity data that 95mg of catalyst is required to process the provided CO2, so the thickness of the catalytic bed is 19mm, which is filled in the middle section of the channel inside the nozzle. The upper and lower ends of the catalytic bed are filled with quartz wool layers, and the thickness of the quartz wool layers at both ends is 1.2mm.

[0113] After the detection gas flows out of the filling column and passes through the catalytic bed, CO2 can be completely converted into CH4, and then the CH4 response signal is obtained through the FID detector, thereby obtaining the corresponding CO2 concentration information. The test results show that the retention time of CH4 converted from CO2 in the FID spectrum is 3.015min, the peak area is 1262844, and the retention time of the original CH4 is 1.044min, the peak area is 1286033. It can be calculated that this catalytic bed can achieve 98.2% conversion of CO2 and 100% CH4 selectivity. Through this device, the detection of trace CO2 can be achieved in an integrated manner.

[0114] Example 7

[0115] This example uses the device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected x The concentration is usually lower than 0.1v%. In this example, in order to verify the actual catalytic bed for trace CO x The conversion capacity provides the CO in the gas to be detected. x The volume concentration is 200 ppm, of which the volume concentrations of CO and CO2 are 100 ppm and 100 ppm respectively, and 100 ppm CH4 is added as an internal standard, and the balance gas is Ar.

[0116] The devices used are as Figure 1 As shown, the chromatographic column uses a DB-WAX capillary column with a length of 30m, an outer diameter of 0.53mm, a column thickness of 0.25μm, and a quantitative loop volume of 250μl. This chromatographic column can separate CO, CO2 and CH4.

[0117] Combination of the gas flow path of the gas to be detected, H2 and the makeup gas Figure 2 It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, and H2 and the tail gas are introduced into the gas channel 60. H2 / Ar with a H2 content of 50v% is used as the carrier gas, the capillary column flow rate is 5ml / min, the H2 flow rate introduced into the gas channel is 20ml / min, and the tail gas flow rate is 25ml / min. Air flows in from the nozzle at a flow rate of 400ml / min.

[0118] In the inner channel of the nozzle, the inner diameter of the upper section is 0.8 mm and the length is 10 mm; the inner diameter of the middle section is 1.2 mm and the length is 15 mm; the inner diameter of the lower section is 2 mm and the length is 40 mm.

[0119] CO entering the catalyst bed x The flow rate is 0.001ml / min, and the H2 flow rate is similar to CO xThe flow ratio is 22499.25:1. In this example, Ni-based catalyst is used, the mass fraction of the active component Ni is 60%, and the carrier is Al2O3, the particle size is 60-80 mesh, filled in the nozzle channel. The FID detector is set to 240℃ and can remain unchanged for a long time. It is inferred from the catalyst activity data that the CO provided by the treatment x If 10 mg of catalyst is required, the thickness of the catalyst bed is 10 mm, which is filled in the middle section of the nozzle channel. Quartz wool layers are filled at the upper and lower ends of the catalyst bed, and the thickness of the quartz wool layers at both ends is 1.5 mm.

[0120] The gas to be detected flows out of the capillary column and passes through the catalytic bed, which can x It is completely converted into CH4, and then the CH4 response signal is obtained through the FID detector to obtain the corresponding CO x The test results show that the retention time of CO converted in the FID spectrum is 0.822min, the peak area is 636615, the retention time of CH4 converted from CO2 is 3.014min, the peak area is 630827, and the retention time of the original CH4 is 1.051min, the peak area is 643045. It can be calculated that this catalytic bed can achieve 99% conversion of CO and 100% CH4 selectivity, 98.1% conversion of CO2 and 100% CH4 selectivity. This device can realize the integrated conversion of trace CO x Detection.

[0121] Example 8

[0122] This example uses the device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected x The concentration is usually lower than 0.1v%. In this example, in order to verify the actual catalytic bed for trace CO x The conversion capacity provides the CO in the gas to be detected. x The volume concentration is 200 ppm, of which the volume concentrations of CO and CO2 are 100 ppm and 100 ppm respectively, and 100 ppm CH4 is added as an internal standard, and the balance gas is Ar.

[0123] The devices used are as Figure 1 As shown, the chromatographic column is packed with HayeSep Q, with a length of 1.83m, an outer diameter of 1 / 8 inch, a column thickness of 2mm, and a quantitative loop volume of 1ml. This chromatographic column can separate CO, CO2 and CH4.

[0124] Combination of the gas to be detected and H2 gas flow path Figure 2It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, H2 is introduced into the gas channel 60, high-purity Ar is used as the carrier gas, the column flow rate is 20ml / min, the H2 flow rate introduced into the gas channel is 35ml / min. Air flows in from the nozzle at a flow rate of 350ml / min.

[0125] In the inner channel of the nozzle, the inner diameter of the upper section is 0.8 mm and the length is 10 mm; the inner diameter of the middle section is 1.2 mm and the length is 15 mm; the inner diameter of the lower section is 2 mm and the length is 40 mm.

[0126] CO entering the catalyst bed x The flow rate is 0.004ml / min, and the H2 flow rate is similar to CO x The flow ratio is 8750:1. In this example, Ni-based catalyst is used, the mass fraction of the active component Ni is 40%, and the carrier is a 1:1:5 mixture of Eu2O3, CeO2 and Al2O3, the particle size is 100-120 mesh, filled in the nozzle channel. The FID detector is set to 220℃ and can remain unchanged for a long time. It is inferred from the catalyst activity data that the CO provided by the treatment x 40mg of catalyst needs to be loaded, so the thickness of the catalyst bed is 7.1mm, which is loaded in the middle section of the nozzle inner channel. Quartz wool layers are loaded at the upper and lower ends of the catalyst bed, and the thickness of the quartz wool layers at both ends is 1.2mm.

[0127] The detection gas flows out of the filling column and passes through the catalytic bed to x It is completely converted into CH4, and then the CH4 response signal is obtained through the FID detector to obtain the corresponding CO x The test results show that the FID spectrum shows that the retention time of CO converted is 0.820min, the peak area is 635925, the retention time of CH4 converted from CO2 is 3.017min, the peak area is 633353, and the retention time of the original CH4 is 1.049min, the peak area is 642998. It is calculated that this catalytic bed can achieve 98.9% conversion of CO and 100% CH4 selectivity, 98.5% conversion of CO2 and 100% CH4 selectivity. This device can realize the integrated conversion of trace CO x Detection.

[0128] Example 9

[0129] This example uses the device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected x The concentration is usually lower than 0.1v%. In this example, in order to verify the actual catalytic bed for trace CO xThe conversion capacity provides the CO in the gas to be detected. x The volume concentration is 2000 ppm, of which the volume concentrations of CO and CO2 are 1000 ppm and 1000 ppm respectively, and 1000 ppm CH4 is added as an internal standard, and the balance gas is Ar.

[0130] The devices used are as Figure 1 As shown, the chromatographic column 4 is a DB-WAX capillary column with a length of 30 m, an outer diameter of 0.53 mm, a column thickness of 0.25 μm, and a quantitative loop volume of 250 μl. This chromatographic column can separate CO, CO2, and CH4.

[0131] Combination of the gas flow path of the gas to be detected, H2 and the makeup gas Figure 2 It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, and H2 and the tail gas are introduced into the gas channel 60. High-purity Ar is used as the carrier gas, the capillary column flow rate is 5ml / min, the H2 flow rate introduced into the gas channel is 30ml / min, and the tail gas flow rate is 10ml / min. Air flows in from the nozzle at a flow rate of 400ml / min.

[0132] In the inner channel of the nozzle, the inner diameter of the upper section is 0.5 mm and the length is 10 mm; the inner diameter of the middle section is 1.2 mm and the length is 15 mm; the inner diameter of the lower section is 2 mm and the length is 30 mm.

[0133] CO entering the catalyst bed x The flow rate is 0.01ml / min, and the H2 flow rate is similar to CO x The flow ratio is 3000:1. In this example, a Ni-based catalyst is used, the mass fraction of the active component Ni is 55%, and the carrier is a 1:10 mixture of CeO2 and ZrO2, the particle size of which is 40-50 mesh, filled in the channel inside the nozzle. The FID detector is set to a temperature of 250°C and can remain unchanged for a long time. It is inferred from the catalyst activity data that 10 mg of catalyst is required to process the provided CO2, so the thickness of the catalytic bed is 10 mm, which is filled in the middle section of the channel inside the nozzle. The upper and lower ends of the catalytic bed are filled with quartz wool layers, and the thickness of the quartz wool layers at both ends is 1.5 mm.

[0134] The gas to be detected flows out of the capillary column and passes through the catalytic bed, which can x It is completely converted into CH4, and then the CH4 response signal is obtained through the FID detector to obtain the corresponding CO xThe test results show that the FID spectrum shows that the retention time of CO converted is 0.825min, the peak area is 6399996, the retention time of CH4 converted from CO2 is 3.017min, the peak area is 6412861, and the retention time of the original CH4 is 1.050min, the peak area is 6432157. It is calculated that this catalytic bed can achieve 99.5% conversion of CO and 100% CH4 selectivity, 99.7% conversion of CO2 and 100% CH4 selectivity. This device can realize the integrated conversion of trace CO x Detection.

[0135] Example 10

[0136] This example uses the device provided by the present invention to achieve trace CO x In actual situations, the CO contained in the gas to be detected x The concentration is usually lower than 0.1v%. In this example, in order to verify the actual catalytic bed for trace CO x The conversion capacity provides the CO in the gas to be detected. x The volume concentration is 2000 ppm, of which the volume concentrations of CO and CO2 are 1000 ppm and 1000 ppm respectively, and 1000 ppm CH4 is added as an internal standard, and the balance gas is Ar.

[0137] The devices used are as Figure 1 As shown, the chromatographic column is packed with HayeSep Q, with a length of 1.83m, an outer diameter of 1 / 8 inch, a column thickness of 2mm, and a quantitative loop volume of 1ml. This chromatographic column can separate CO, CO2 and CH4.

[0138] Combination of the gas to be detected and H2 gas flow path Figure 2 It is understood that the gas to be detected and the carrier gas are introduced into the chromatographic column 50, and H2 is introduced into the gas channel 60. Figure 2 As shown, high-purity Ar is used as the carrier gas, the column flow rate is 20ml / min, the H2 flow rate in the gas channel is 30ml / min. Air flows in from the nozzle at a flow rate of 400ml / min.

[0139] In the inner channel of the nozzle, the inner diameter of the upper section is 0.5 mm and the length is 10 mm; the inner diameter of the middle section is 1.2 mm and the length is 20 mm; the inner diameter of the lower section is 2 mm and the length is 40 mm.

[0140] CO entering the catalyst bed x The flow rate is 0.04ml / min, and the H2 flow rate is similar to CO xThe flow ratio is 750:1. In this example, a Ni-based catalyst is used, the mass fraction of the active component Ni is 45%, and the carrier is a 1:1 mixture of SiO2 and Sm2O3, the particle size is 50-60 mesh, and it is filled in the nozzle channel. The FID detector is set to 250℃ and can remain unchanged for a long time. It is inferred from the catalyst activity data that the CO provided by the treatment x 80mg of catalyst needs to be loaded, so the thickness of the catalyst bed is 15mm, which is loaded in the middle section of the nozzle inner channel. Quartz wool layers are loaded at the upper and lower ends of the catalyst bed, and the thickness of the quartz wool layers at both ends is 1.2mm.

[0141] The detection gas flows out of the filling column and passes through the catalytic bed to x It is completely converted into CH4, and then the CH4 response signal is obtained through the FID detector to obtain the corresponding CO x The test results show that the retention time of CO converted in the FID spectrum is 0.826min, the peak area is 6354815, the retention time of CH4 converted from CO2 is 3.016min, the peak area is 6374111, and the retention time of the original CH4 is 1.046min, the peak area is 6431999. It can be calculated that this catalytic bed can achieve 98.8% conversion of CO and 100% CH4 selectivity, 99.1% conversion of CO2 and 100% CH4 selectivity. This device can realize the integrated conversion of trace CO x Detection.

[0142] Results and conclusions: Combining Examples 1 to 10, it can be seen that the present invention adopts Figure 1 The FID device shown is effective for samples containing low concentration (100 ppm to 2000 ppm) CO x When testing the gas to be tested, due to different CO x The separation time required for separation of CO and CO2 by gas chromatography columns is different, so different CO x The response time of CH4 obtained by conversion is also different when detected by FID detector. Different CO x The CH4 content value obtained by conversion can then be used to obtain the different CO x In addition, to verify the concentration of CO x In order to obtain a high conversion rate and selectivity of CH4, the same volume of CH4 was used as an internal standard in the embodiment of the present invention. By comparing the different CO x The peak area of ​​CH4 obtained by conversion and the peak area of ​​CH4 used as internal standard were used to verify the CO xThe conversion rate and selectivity of CH4 during catalytic conversion can be seen from the test results of Examples 1 to 10 of the present invention (Examples 1 to 2 are mainly used as controls), the low concentration CO x The FID device and method for methanogenic conversion and detection can achieve low-concentration CO without the use of external heating, temperature control and insulation equipment. x detection, and has the advantages of high accuracy and good reliability.

[0143] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0144] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method to achieve low concentration CO x The FID device for methanogenic conversion and detection is characterized in that: include: Nozzle housing; a nozzle inner channel, the nozzle inner channel penetrates the nozzle housing along the height direction of the nozzle housing, the nozzle inner channel comprises an upper section, a middle section and a lower section which are sequentially connected from top to bottom, the inner diameter of the upper section is smaller than the inner diameter of the middle section, the inner diameter of the middle section is smaller than the inner diameter of the lower section, the inner diameter of the connection between the upper section and the middle section gradually increases from top to bottom, and the inner diameter of the connection between the middle section and the lower section gradually increases from top to bottom; The length of the upper section is shorter than the length of the middle section, and the length of the middle section is shorter than the length of the lower section; A catalytic bed, the catalytic bed is arranged in the middle section of the nozzle inner channel, the catalytic bed comprises a Ni-based catalyst, and the Ni-based catalyst comprises metal Ni and a metal oxide; A quartz wool layer, the quartz wool layer is arranged in the middle section of the inner channel of the nozzle, and the quartz wool layer comprises an upper quartz wool layer and a lower quartz wool layer for fixing the catalytic bed layer; Chromatographic column, the chromatographic column CO x The gas outlet end passes through the lower section of the nozzle inner channel and stops at the lower quartz wool layer, and a gas channel is formed between the chromatographic column and the nozzle inner channel; In the Ni-based catalyst, the content of the metal oxide is 10-60wt%.

2. The FID device according to claim 1, characterized in that: The upper part of the nozzle housing is in the shape of a cone, a pyramid, an inner curved surface cone or an outer curved surface cone.

3. The FID device according to claim 1, characterized in that: The Ni-based catalyst includes metal Ni and a metal oxide carrier, the metal oxide carrier includes at least one selected from Al2O3, SiO2, CeO2, La2O3, Eu2O3, ZrO2, and Sm2O3, and the mass ratio of the metal Ni to the metal oxide carrier is (40~90):(10~60).

4. The FID device according to claim 1, characterized in that: The particle size of the catalyst used in the catalytic bed is 40-200 meshes.

5. The FID device according to claim 1, characterized in that: The thickness of the catalytic bed layer is 5-40 mm, and the thickness of the upper quartz wool layer and the lower quartz wool layer are independently 0.5-3 mm.

6. The FID device according to any one of claims 1 to 5, characterized in that: The chromatographic column is a capillary column or a packed column.

7. The FID device according to any one of claims 1 to 5, characterized in that: In the inner channel of the nozzle, the inner diameter of the upper section is 0.1-3 mm, and the length is 1-20 mm; the inner diameter of the middle section is 1-6 mm, and the length is 6-30 mm; the inner diameter of the lower section is 2-10 mm, and the length is 10-80 mm.

8. The FID device according to any one of claims 1 to 5, characterized in that: The lower middle part of the nozzle housing is detachably connected to the base, and the base is arranged below the nozzle housing.

9. The FID device according to claim 8, characterized in that: The nozzle housing is connected to the base via threads.

10. The FID device according to claim 8, characterized in that: The nozzle housing further comprises an insulating transition layer, which is arranged above the connection position between the nozzle housing and the base and separates the nozzle housing into two parts which are not connected to each other.

11. A method for achieving low concentration CO by using the FID device according to any one of claims 1 to 10 x The method for methanogenic conversion and detection is characterized in that: include: (1) Carrying CO x The gas to be detected flows out of the chromatographic column and enters the catalytic bed layer, so that H2 enters the catalytic bed layer from the gas channel; (2) Make the CO in the gas to be detected x reacting with H2 at the operating temperature of the catalyst bed and the FID detector to produce CH4 and H2O; (3) allowing the chromatographic column carrier gas, H2 and CH4 to flow out of the catalytic bed layer and merge into one channel in the upper section of the nozzle channel and flow out through the nozzle opening; (4) The air meets the H2 flowing out of the nozzle above the nozzle, forming a hydrogen flame ionization zone. The hydrocarbons are ionized in the flame zone to form positive ions, which are collected and moved under the action of the negative electrostatic field to form a weak current. The weak current is amplified by the electrometer to form a detection signal. The detected CH4 content is obtained based on the detection signal, so as to infer the CO content in the gas to be detected. x The content value.

12. The method according to claim 11, characterized in that Before step (1), the component to be detected, CO, is separated from the sample gas using a chromatographic column. x , and obtain the gas to be detected.

13. The method according to claim 11, characterized in that In step (1), the carrier gas used in the chromatographic column is at least one selected from high-purity Ar, high-purity He, high-purity N2 and high-purity H2.

14. The method according to claim 13, characterized in that In step (1), the flow rate of the carrier gas is 2-50 ml / min, the flow rate of H2 flowing into the gas channel is 20-40 ml / min, and the volume ratio of H2 to the carrier gas is 0.4-50.

15. The method according to claim 11, characterized in that In step (1), H2 and tail gas are allowed to enter the catalytic bed from the gas channel, and the flow rate of the tail gas is 10-30 ml / min.

16. The method according to claim 11, characterized in that In step (4), the air flow rate is 200-400 ml / min.

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