JP2007333543A - Analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent destruction of the functions and the structure of a catalytic analyzer and the hazards to a person measuring caused by the ignition of a sample contained in ignitable components of high concentration. <P>SOLUTION: In this analyzer, a switching valve 21 and an ignitable component detector 22 of a prinsiple that will not cause the risk of ignition caused by volatile components in the sample are arranged on the downstream side of a sample inlet port 1 and the switching valve 21 is first changed over toward a flow channel C while preparatory measurement for confirming that there is no hazard of ignition, when the sample is introduced into a combustion furnace 3 is performed by an ignitable component detector 22. Thereafter, the switching valve 21 is changed-over toward a switching valve 2, and the final measurement by a detector 9 is performed. When the hazard of ignition is not recognized by the preparatory measurement, the switching valve 21 is fixed in the direction of the ignitable component detector 22 or is changed-over, to a position where both directions of the switching valve 2 and the ignitable component detector 22 are closed and final measurement is stopped. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a catalytic analyzer such as a volatile organic carbon analyzer used in the field of analytical measurement.

Hereinafter, a catalytic oxidation type volatile organic carbon analyzer using NDIR (non-dispersive infrared analyzer) as a detector (hereinafter referred to as VOC and volatile organic carbon analyzer as VOC meter). As an example, the background art of a conventional catalytic oxidation analyzer will be described. In this type of VOC meter (see, for example, Patent Document 1), a fluid sample (hereinafter abbreviated as “sample”) is first passed through an oxidation catalyst heated to a high temperature, and volatile organic carbon (hereinafter referred to as “VOC”) in the sample is passed through. The total amount of carbon dioxide (hereinafter abbreviated as “CO _2” ) is converted into carbon dioxide (hereinafter referred to as “CO _2” ), and the resulting CO ₂ concentration is detected by NDIR, converted into a VOC concentration, and output. NDIR is a detection method by irradiating infrared rays from the light source to the CO _2, to measure the infrared absorption of CO ₂ specific wavelength. By this method, highly sensitive continuous measurement of VOC is performed.

  In FIG. 4, reference numeral 1 denotes a sample introduction port, from which a sample is introduced into the VOC meter, and flows to the right in the figure by the suction force of the pump 6. The switching valve 2 switches the flow path from the sample introduction port 1 to either the flow path A direction or the flow path B direction. Portions from the switching valve 2 to the pump 6 in the flow path A and the pump 8 in the flow path B constitute a sample pretreatment unit P.

A combustion furnace 3 incorporating a catalyst tank 3C is disposed downstream of the switching valve 2 on the flow path A side. For example, a platinum-based oxidation catalyst (not shown) is enclosed in the catalyst tank 3C. At the time of measurement, the combustion furnace 3 is heated to a specified temperature by the heater 3H, and the VOC in the sample is converted to CO ₂ when passing through the high temperature catalyst tank 3C. Depending on the sample, hydrogen chloride / hydrogen fluoride which affects the measurement is generated in the catalyst tank 3C, but these components are removed by the halogen scrubber 4. The gas-liquid separator 5 has a built-in cooler to remove moisture in the sample. The sample that has passed through the pump 6 is introduced into an NDIR type detector 9. The sample is irradiated with infrared light from an IR light source (not shown) in the detector 9, and the amount of infrared absorption generated at a wavelength unique to CO ₂ is measured. When the switching valve 2 is switched to the flow path B side, the sample passes through the gas-liquid separator 7 and the pump 8 without being changed by the combustion furnace 3 and is introduced into the detector 9.

At the time of measurement, the sample is first guided to the detector 9 via the flow path B by switching the switching valve 2, and the measured value is stored in the calculation unit 10. By this step, CO ₂ contained from the beginning in the sample is measured and stored. This measured value is used as a background value. Next, the sample is guided to the detector 9 via the flow path A, and the measured value is stored in the calculation unit 10. This measured value is taken as the total value. Further, the calculation unit 10 subtracts the background value from the total value and converts the measured value after the subtraction into the VOC concentration, thereby obtaining an output corresponding to the VOC concentration in the sample. This output is displayed and recorded on the recorder 11. In addition, periodic automatic switching (chopping) of the switching valve 2 is performed, signal processing synchronized with the automatic switching of the switching valve 2 is performed in the arithmetic unit 10, and the background value is automatically subtracted from the total value at all times. It is also possible to output continuously.

JP 9-33509 A

  The structure of the conventional VOC meter is as described above, but this structure has a problem in the safety of the VOC meter. That is, the oxidation efficiency of the oxidation catalyst in the VOC meter is required to be 95% or more, and the oxidation catalyst is used in a high-temperature atmosphere using an electric heater or the like in order to prevent a reduction in the oxidation efficiency and extend the life of the oxidation catalyst. However, if the sample to be measured contains ignitable components such as volatile organic compounds and a sample containing a high concentration of ignitable components touches the oxidation catalyst, Even if the temperature of the oxidation catalyst exceeds the ignition point of the sample due to the ignitable component or the initial oxidation catalyst temperature does not exceed the ignition point, the temperature of the oxidation catalyst temporarily rises due to the oxidation reaction of the sample, and ignition occurs. If the number of points is exceeded, the sample will ignite, which may impair the function and structure of the VOC meter and cause danger to the measurer. The object of the present invention is to provide means for solving such problems.

  In order to solve the above-mentioned problems, the present invention includes a high-temperature catalyst tank for catalyst treatment disposed in a flow path of a fluid sample and a detector disposed downstream thereof, and a fluid chemically reacted in the catalyst tank. In an analyzer for analyzing a sample with a detector, an ignition component detector for preliminarily measuring the concentration of an ignitable component of a fluid sample is provided separately from the detector. Also, there is provided means for stopping the introduction of the fluid sample into the catalyst tank when the ignition component detector detects an ignitable component concentration higher than a predetermined concentration in the fluid sample. In addition, a means for monitoring the temperature of the catalyst tank and reducing the heating of the catalyst tank when the temperature or the gradient of the temperature rise exceeds a predetermined threshold value is provided. Also, a gas inlet is provided via an inlet valve connected to the upstream flow path of the catalyst tank, and when the temperature of the catalyst tank or the gradient of temperature rise exceeds a predetermined threshold, the inlet valve is opened and the gas is opened. A means for introducing non-flammable gas from the inlet is provided. A shut-off valve is provided in the upstream channel of the catalyst tank to shut off the fluid sample when the temperature of the catalyst or the gradient of temperature rise exceeds a threshold value.

  According to the present invention, when a highly volatile sample having an ignitability is inhaled, it is possible to avoid the risk of ignition / explosion of the apparatus and improve the measurement safety.

  The first feature of the analyzer provided by the present invention is that it comprises a high-temperature catalyst tank for catalyst treatment disposed in the flow path of the fluid sample and a detector disposed downstream thereof, and a chemical reaction is carried out in the catalyst tank. In the analysis apparatus for analyzing the fluid sample with a detector, an ignition component detector for preliminarily measuring the concentration of the ignitable component of the fluid sample is provided separately from the detector, and the second feature is a catalyst. A means for reducing the heating of the catalyst tank when the temperature of the tank or the gradient of the temperature rise exceeds a predetermined threshold is provided. A third feature is that an introduction valve is provided in the upstream flow path of the catalyst tank. A gas introduction port for introducing non-flammable gas and a shut-off valve for shutting off the fluid sample are provided, and the form having these features is the best form.

  This will be described with reference to the illustrated example. FIG. 1 shows the configuration of Embodiment 1 of the present invention. In FIG. 1, the structure and operation of components having the same reference numerals as in FIG. 4 are the same as those in FIG. The sample introduced from the sample introduction port 1 is guided to the switching valve 2 direction or the flow path C direction by the switching valve 21. An ignition component detector 22 is disposed downstream of the flow path C. As the ignition component detector 22, for example, a principle that does not cause ignition due to an inflammable component in a sample, such as a semiconductor-type combustible gas detector, is used. The combustible gas detector uses the change in electrical conductivity due to the chemisorption of combustible gas on the metal oxide semiconductor. Unlike the detection method of the oxidation catalyst-NDIR method, qualitative analysis of components is impossible and quantitative accuracy However, even if the ignitable component in the sample has a high concentration, the concentration of the ignitable component can be measured without fear of ignition. Therefore, when the sample is introduced into the combustion furnace 3 by first switching the switching valve 21 to the flow path C side at the time of measurement and performing measurement by the ignition component detector 22 (hereinafter referred to as preliminary measurement). You can check if there is a risk of ignition. After this confirmation is completed, the switching valve 21 is switched in the switching valve 2 direction, and measurement by the detector 9 (hereinafter referred to as main measurement) is performed. Since the structure on the right side of the switching valve 2 and the procedure of this measurement are the same as the conventional method shown in FIG. If the risk of ignition is recognized by the preliminary measurement, the switching valve 21 is operated as a means for stopping the introduction of the fluid sample into the catalyst tank, and is fixed at the preliminary measurement position, that is, in the direction of the ignition component detector 22. Or switch to a position where both the switching valve 2 and the ignition component detector 22 are closed, and the measurement is stopped. After necessary sample pretreatment such as sample concentration reduction processing is performed outside the apparatus, the process returns to preliminary measurement and proceeds.

  FIG. 2 shows the configuration of Embodiment 2 of the present invention. In FIG. 2, the structure and operation of components having the same reference numerals as in FIG. 4 are the same as those in FIG. The sample introduced from the sample introduction port 1 flows to the right in the figure by the suction force of the pump 6 or the pump 8, and is guided to the detector 9 via the sample pretreatment part P. Since the structure from the sample pretreatment part P to the detector 9 is similar to that shown in FIG. An ignition component detector 23 of the same type as the ignition component detector 22 described in the first embodiment is disposed further downstream of the detector 9, and the sample further passes through the detector 9 and then the ignition component detector 23. It passes through and is discharged outward.

  At the time of measurement, the sample is first guided to the detector 9 via the flow path B by switching the switching valve 2, and the measured value is stored in the calculation unit 10. Simultaneously with this step, the sample is also introduced into the ignition component detector 23, and preliminary measurement for the same purpose as in the first embodiment, that is, whether or not there is a risk of ignition when the sample is introduced into the combustion furnace 3 is confirmed. When it is confirmed in the preliminary measurement that there is no risk of ignition, the switching valve 2 is switched to the flow path A side and the main measurement is performed. Since this measurement is performed in accordance with the conventional method shown in FIG. 4, a detailed description is omitted. In this case, the measurement via the flow path B described in the conventional method has already been completed in the preliminary measurement stage, and therefore omitted. May be. When it is confirmed in the preliminary measurement that there is a risk of ignition, the switching valve 2 is fixed in the position of the preliminary measurement, that is, in the direction of the channel B as a means for stopping the introduction of the fluid sample into the catalyst tank, or the channel A , B are switched to a position that is closed in both directions, and the measurement is stopped. After necessary sample pretreatment such as sample concentration reduction processing is performed outside the apparatus, the process returns to preliminary measurement and proceeds.

  FIG. 3 shows the configuration of Embodiment 3 of the present invention. In FIG. 3, the structure and operation of components having the same reference numerals as in FIG. 4 are the same as those in FIG. In FIG. 3, the sample is guided to the switching valve 2 via the switching valve 24. Portions from the switching valve 2 to the pump 6 in the channel A and the pump 8 in the channel B constitute a sample pretreatment unit PN.

  The combustion furnace 26 is heated by a heater 26H. The combustion furnace 26 is equipped with a fan-type cooler 27. There is a catalyst tank 26C in the combustion furnace 26, and the temperature of the catalyst tank 26C is constantly monitored by temperature measuring means such as a thermocouple. Although the temperature of the combustion furnace 26 at the time of measurement is kept constant, the temperature of the catalyst tank 26C is the temperature of the combustion furnace 26 and the amount of heat generated during the reaction between the sample and the oxidation catalyst (not shown) in the catalyst tank 26C. Therefore, when the concentration of the volatile component is excessive, the amount of heat generated by the reaction is specifically increased, and the temperature of the catalyst tank 26C is rapidly increased as compared with the general measurement. When the temperature or the gradient of the temperature rise exceeds a predetermined threshold value, it is determined that there is a risk of ignition, the energization of the heater 26H is stopped, and the cooler 27, which is a means for reducing the heating of the catalyst tank 26C, is provided. Operate to cool the catalyst tank 26C. Further, the switching valve 24, which is a means for introducing non-flammable gas, the filter F, and the gas introduction port 25 are used to switch the switching valve 24 from the sample introduction port 1 side to the filter F direction, and the gas introduction port 25. Then, the air is introduced through the filter F and the flow of the sample is cut off at the same time.

  The present invention is not limited to the above-described embodiments, and various modified embodiments can be given. For example, for each of the examples, the detector 9 of this measurement has been described by NDIR, but the detector 9 is not limited to NDIR. It is also possible to generate an appropriate light alarm or acoustic alarm in any process, such as when a high concentration of ignitable components is detected in the preliminary measurement. Further, in the third embodiment, the function of the switching valve 24 is divided into two, a shut-off valve dedicated to shutting off the sample introduction is provided at the position of the switching valve 24, and a start / stop switching of the air introduction start / stop is provided upstream of the switching valve 2. These valves may be provided, and only one or both of the above valves may be operated as necessary. The non-flammable gas includes air, but other non-flammable gases such as nitrogen may be used. The filter F is not necessary when non-ignitable gas is supplied from the outside via the filter, and is not essential to the present invention. Moreover, although the forced air cooling system by a cooling fan is illustrated and demonstrated as the cooler 27, if the system of the cooler 27 has a cooling effect, it will not be limited to a forced air cooling system, and the refrigerant | coolant was used. Other methods such as a rapid cooling method may be used. It is also conceivable that a plurality of threshold values are set according to the temperature of the catalyst tank 26C or the gradient of temperature rise, and the operations of the cooler 27 and the switching valve 24 are operated stepwise according to the respective threshold values. Stepwise operation can be applied to Examples 1 and 2 as necessary. For example, in the first embodiment, a plurality of threshold values are set for the output of the ignition component detector 22, and stepwise flow control is performed by a flow rate control valve (not shown in FIG. 1) added downstream of the switching valve 2 with the output. You can also Also, in Examples 1 to 3, the operation of each element is linked and automated, and when the risk of ignition is confirmed, the sample is shut off immediately or stepwise or the temperature of the catalyst tank 26C is reduced. Moreover, the analyzer which overlap | superposed and provided each element or means of Examples 1-3 may be used. Furthermore, although each said Example demonstrated gaseous VOC, if this invention is an analyzer which has a high temperature catalyst tank for catalyst processing, it can be applied also to a liquid sample. The present invention includes all of these.

  The present invention can be applied to a catalytic analyzer such as a volatile organic carbon analyzer used in the analytical measurement field.

It is a figure which shows the structure of Example 1 of this invention. It is a figure which shows the structure of Example 2 of this invention. It is a figure which shows the structure of Example 3 of this invention. It is a figure which shows the structure of the conventional analyzer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sample inlet 2 Switching valve 3 Combustion furnace 3C Catalyst tank 3H Heater 4 Halogen scrubber 5 Gas-liquid separator 6 Pump 7 Gas-liquid separator 8 Pump 9 Detector 10 Calculation part 11 Recorder 21 Switching valve 22 Ignition component detector 23 Ignition component detector 24 Switching valve 25 Gas inlet 26 Combustion furnace 26C Catalyst tank 26H Heater 27 Cooler F Filter P Sample pretreatment unit PN Sample pretreatment unit

Claims (5)

  An analysis apparatus comprising a high-temperature catalyst tank for catalyst treatment disposed in a flow path of a fluid sample and a detector disposed downstream thereof, wherein the fluid sample chemically reacted in the catalyst tank is analyzed by the detector. An analyzer comprising an ignition component detector for preliminarily measuring the concentration of an ignitable component of a fluid sample separately from the detector.   2. A means for stopping introduction of a fluid sample into a catalyst tank when an ignitable component concentration equal to or higher than a predetermined concentration is detected in the fluid sample by the ignition component detector. Analysis equipment.   An analysis apparatus comprising a high-temperature catalyst tank for catalyst treatment disposed in a flow path of a fluid sample and a detector disposed downstream thereof, wherein the fluid sample chemically reacted in the catalyst tank is analyzed by the detector. An analyzer provided with means for monitoring the temperature of the tank and reducing the heating of the catalyst tank when the temperature or the gradient of temperature rise exceeds a predetermined threshold.   A gas inlet is provided via an inlet valve connected to the upstream flow path of the catalyst tank, and when the temperature of the catalyst tank exceeds a predetermined threshold, the inlet valve is opened and non-flammable from the gas inlet. 4. The analyzer according to claim 3, further comprising means for introducing the gas.   5. The analyzer according to claim 3, wherein a shut-off valve for shutting off a fluid sample when a temperature of the catalyst or a gradient of temperature rise exceeds a threshold value is provided in the upstream channel of the catalyst tank.

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