JP2015197306A - Device and method for analyzing gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an analyzing device and an analyzing method capable of analyzing a gas containing high concentration of mercury.SOLUTION: There are provided an analyzing device of a gas containing mercury and water vapor including: at least, a gas collection part for collecting a sample gas; a heating conduit 2 for allowing the sample gas to flow; a gas fractionator 10 for fractionating a part of the sample gas; a gas mixer 7 for mixing the fractionated sample gas with a dilution gas and forming a measurement gas; water content detection means 40; a mercury spectrometer 11; verification means for verifying a dilution ratio by the dilution gas based on a measurement result such as mercury concentration; and control means for adjusting the dilution ratio of the sample gas so that the concentration such as mercury in the measurement gas is less than a saturated concentration at a dew-point temperature of 8°C, as well as a method for analyzing by using the device.

Description

The present invention relates to an analysis apparatus and an analysis method for analyzing mercury in a gas containing metal mercury or a water-soluble mercury compound such as HgCl ₂ , or both of them and water vapor at a high concentration. Specifically, the present invention relates to an analysis apparatus and an analysis method capable of accurately measuring the mercury concentration in a gas containing a high concentration of mercury or the like that is generated when a mercury-containing material is heated.

The method for measuring the mercury concentration in the exhaust gas is defined by JIS, and according to the mercury analysis method in the exhaust gas according to JIS K0222, the following method is defined.
(1) Wet absorption-reduction vaporization atomic absorption method A sample gas is collected with a collection tube equipped with a heat-retaining heater, passed through an absorption bottle, and mercury in the gas is dissolved in the absorbing solution. A method of measuring the amount of mercury in this absorbing solution by reductive vapor atomic absorption spectrometry.
(2) Gold amalgam collection-Heat vaporization atomic absorption method Sample gas is collected with a collection tube equipped with a heat insulation heater, and after passing through a gas washing bottle and a moisture absorption bottle, it is passed through a mercury collection tube and mercury in the gas is removed. Collect as gold amalgam. A method of measuring collected mercury by thermal vaporization atomic absorption spectrometry.
(3) Continuous measurement method A method in which a gas is continuously collected, passed through a reduction vaporizer, and then the mercury concentration in the gas is measured with a cold atomic absorption device.

  In addition, many are known as such a continuous analysis method of mercury. For example, Japanese Patent Application Laid-Open No. 2002-82110 (Patent Document 1) discloses a method in which a gas is continuously collected and water-soluble in the gas. After absorbing the mercury with the absorption liquid, the water-soluble mercury in the absorption liquid is reduced, converted to gaseous metallic mercury, led to the mercury analyzer, and the metallic mercury in the gas not absorbed by the absorbing liquid is gaseous. A method and apparatus for measuring the concentration of mercury in a gas is described which can be directly guided to a mercury analyzer and separately analyzed for water-soluble mercury and water-insoluble mercury contained in the gas. Further, JP 2001-33434 A (Patent Document 2) discloses that a gas is passed through a reduction reactor filled with a stannous chloride reducing agent, and mercury ions of mercuric chloride in the gas are converted into metal ions. A mercury analysis method and apparatus for reducing to mercury and analyzing the reduced metallic mercury is described.

JP 2002-82110 A JP 2001-33434 A

However, in the conventional method, the bottle of the absorbing liquid, the gas cleaning liquid, or the reducing liquid is not heated and kept warm. Therefore, when measuring the mercury concentration of a gas containing metal mercury or water-soluble mercury at a high concentration, the temperature of the gas rapidly decreases at the inlet, outlet, and inside of the absorption liquid, gas cleaning liquid, reducing liquid, etc. To do. When this temperature was below the dew point of mercury or the like, the mercury or the like condensed and adhered to the inside of the analytical instrument, and an accurate concentration could not be measured. In addition, even when water vapor in the gas is condensed, water-soluble mercury is dissolved in the condensed water, and an accurate mercury concentration cannot be measured. Furthermore, the range of mercury concentration that can be measured by the above-mentioned JIS or the like is at most about 1 μg / m ^{3 to 5} mg / m ³ , and a gas containing high concentration mercury exceeding such a range could not be measured.
The present invention has been made in view of such a current situation, and prevents adhesion of mercury and water vapor in an analytical instrument and dissolution of soluble mercury in condensed water, and enables measurement at an accurate concentration. In addition, an object of the present invention is to provide an analyzer and an analysis method that enable analysis of a gas containing mercury at a high concentration exceeding 1 μg / m ^{3 to 5} mg / m ³ defined by JIS.

  The present inventors continuously sampled a sample gas while being heated and kept at a temperature exceeding the dew point of mercury and water vapor, and then fractionated a part of this gas to dilute air, etc. The concentration of mercury and water vapor is reduced to below the saturation concentration of 8 ° C., preventing adhesion of mercury and water vapor into the analytical instrument and dissolution of soluble mercury in condensed water. The inventors found that the concentration can be measured, and completed the present invention based on this finding. That is, the present invention is as follows.

(1) A gas analyzer including a gas containing mercury and water vapor, and collecting a sample gas containing mercury and water vapor while being heated and kept warm so that the mercury and water vapor maintain a gaseous state; A heated and insulated heating conduit for flowing the sample gas collected in the gas sampling section, a heated and insulated gas fractionator for separating a part of the sample gas flowing in the heated conduit, and the collected sample gas A dilution gas introduction pipe for introducing a dilution gas for dilution; a dilution gas heater for heating the introduced dilution gas; and a heating and heat insulation heating conduit for introducing the heated dilution gas into the gas fractionator. The sample gas collected by the gas preparator, the diluted gas introduced into the gas preparator, and a separate diluting gas are introduced if necessary, and these gases are mixed and diluted with the measurement gas. Gas mixer to form and sample The moisture concentration detection means for measuring the water vapor concentration in the gas, the mercury analyzer for measuring the mercury concentration in the diluted measurement gas, the measurement result of the mercury concentration in the measurement gas, and the water vapor concentration in the sample gas Based on the measurement results, the verification means for verifying the dilution ratio with the dilution gas and the dilution ratio of the sample gas are adjusted so that the concentration of mercury and water vapor in the diluted measurement gas is less than the saturation concentration at the dew point of 8 ° C. Control means for calculating the mercury concentration in the obtained measurement gas, the measurement result of the water vapor concentration in the sample gas and the calculation means for calculating the mercury concentration in the sample gas by the dilution factor, and the obtained calculation result And an indicator for displaying at least the mercury concentration.
Further, in this gas analyzer, the heating conduit is heated and kept at a temperature at which mercury and water vapor in the sample gas can maintain a gaseous state, preferably at 130 ° C. or higher, and air is used as a dilution gas. Is preferably used. Furthermore, the gas analyzer includes a filter for removing contaminants (for example, solid particles) in the sample gas collected by the gas sampling unit downstream of the gas sampling unit, and a gas fraction upstream of the gas separator. Bypassing the take-in machine and providing a heating and heat-insulating heating conduit communicating with the gas mixer via the mass flow controller, the dilution gas introduction pipe being provided with a dehumidifier and an adsorption removal device, sample gas A temperature detection means for measuring the temperature of the gas, the temperature of the dilution gas, the temperature of the measurement gas, and the temperature of the gas after analysis, and a moisture concentration detection means for measuring the water vapor concentration of the measurement gas Are preferred respectively.

(2) A method for analyzing a gas containing mercury and water vapor, the step of tentatively determining the dilution ratio, which is the mixing ratio of the sample gas and the dilution gas, and the sample gas in the gas sampling section, and mercury and water vapor in the gas A process of collecting while heating and keeping warm so as to maintain the state, a process of heating the sample gas collected in the gas sampling part, flowing it to the heated heating conduit, and heating a part of the sample gas flowing in the heating conduit, A process of separating with a heated gas fractionator, a heated dilution gas is introduced into the gas fractionator, a sample gas fractionated with the gas fractionator and a dilution gas introduced into the gas fractionator; , A step of separately introducing dilution gases as necessary, mixing these gases, obtaining a measurement gas diluted at a provisional dilution factor, a step of measuring the mercury concentration in the measurement gas, and a sample Separate measurement of water vapor concentration in gas Based on the water vapor concentration in the obtained sample gas and the mercury concentration in the measurement gas, the step of verifying the dilution rate and the obtained verification result indicate that the dilution rate is inappropriate. Prepare a measurement gas by adjusting the dilution rate of the sample gas so that the concentration is less than the saturation concentration of 8 ° C dew point, and the adjusted dilution rate, and measure the mercury concentration in the measurement gas The process of verifying the dilution rate is repeated, and if the dilution rate is determined to be appropriate based on the obtained verification result, the measurement result of the mercury concentration in the obtained measurement gas, the sample gas This is a gas analysis method having a calculation step of calculating a mercury concentration based on a measurement result of water vapor concentration and a dilution factor, and a step of displaying at least the mercury concentration based on the obtained calculation result.

(3) A method for analyzing a gas containing mercury and water vapor, the step of tentatively determining the dilution ratio, which is the mixing ratio of the sample gas and the dilution gas, and the sample gas in the gas sampling section, and the mercury and water vapor in the gas A process of collecting while heating and keeping warm so as to maintain the state, a process of heating the sample gas collected in the gas sampling part, flowing it to the heated heating conduit, and heating a part of the sample gas flowing in the heating conduit, A process of separating with a heated gas fractionator, a heated dilution gas is introduced into the gas fractionator, a sample gas fractionated with the gas fractionator and a dilution gas introduced into the gas fractionator; , A step of separately introducing dilution gases as necessary, mixing these gases, obtaining a measurement gas diluted at a provisional dilution factor, a step of measuring the mercury concentration in the measurement gas, and a sample Separate measurement of water vapor concentration in gas Based on the water vapor concentration in the obtained sample gas and the mercury concentration in the measurement gas, the step of verifying the dilution rate and the obtained verification result indicate that the dilution rate is inappropriate. Prepare a measurement gas by adjusting the dilution rate of the sample gas so that the concentration is less than the saturation concentration of 8 ° C dew point, and the adjusted dilution rate, and measure the mercury concentration in the measurement gas The process of verifying the dilution factor is repeated, and if the dilution factor is determined to be appropriate based on the obtained verification result, the step of determining the dilution factor and the sample gas according to the determined dilution factor When diluting a sample gas, a step of continuously obtaining a sample gas for dilution without separating a part of the sample gas with a gas separator, and introducing the dilution gas into the obtained sample gas Mixing with a mixer to obtain a measurement gas with a determined dilution ratio, continuously measuring the mercury concentration in the measurement gas with the obtained measurement gas, and the obtained measurement A measurement result of mercury concentration in the gas, a measurement result of water vapor concentration in the sample gas and a calculation step of calculating the mercury concentration based on the dilution factor, and a step of displaying at least the mercury concentration based on the obtained calculation result This is a gas analysis method.

(4) In addition, when the mercury concentration is continuously measured by the gas analysis method of (3) above, when the mercury and water vapor concentrations in the sample gas change, the determined dilution factor is used. The method further includes the step of verifying the dilution rate based on the water vapor concentration in the prepared sample gas and the mercury concentration in the measurement gas, and adjusting the dilution rate by adjusting the dilution rate of the sample gas based on the verification result. The gas analysis method according to (3), further including a step of obtaining a measurement gas having a changed dilution ratio and continuously measuring the mercury concentration in the obtained measurement gas again.
These gas analysis methods described in the above (2), (3) and (4) all have a heating conduit at a temperature at which mercury and water vapor in the sample gas can maintain a gaseous state. In addition, it is preferable to operate by heating and maintaining at 130 ° C. or higher, and it is preferable to use air as a dilution gas, respectively. Furthermore, these gas analysis methods are used in the sample gas collected by the gas sampling unit. A step of removing contaminants (for example, solid particles) by a filter provided downstream of the gas sampling unit, a step of removing moisture through a dehumidifier, and a desorption gas introduced into the gas preparator and an adsorption removing device The temperature of the sample gas, the temperature of the dilution gas, the temperature of the gas for measurement, and the temperature of the gas after analysis by the temperature detection means. Providing the constant to process, it is, respectively preferably comprises a step of water vapor concentration of the measuring gas is measured by the water concentration detection means.
The gas analysis method of (4) above is provided in case the mercury concentration in the sample gas fluctuates when the mercury concentration is continuously measured by the gas analysis method of (3) above. A new dilution factor is calculated based on the measurement result, and the mercury concentration in the sample gas is continuously measured again by the calculated dilution factor.

According to the present invention, the measurement range defined by the continuous measurement method of JIS K0222, the concentration in the range of 1 μg / m ^{3 to} 10 g / m ³ greatly exceeding the range of 1 μg / m ^{3 to 5} mg / m ³ is accurately measured. can do.

It is a block diagram which shows the outline | summary of the analyzer of this invention.

The present invention is a mercury analyzer and analysis method capable of accurately measuring a mercury concentration in a gas having a mercury concentration in the range of 1 μg / m ^{3 to} 10 g / m ³ . For this reason, the apparatus of the present invention heats and keeps the pipes at a temperature of 130 ° C. or higher so as to prevent water vapor and mercury from condensing in the pipes of the apparatus and maintain the gas state. The sample gas is diluted and analyzed so that the concentration of water vapor and water vapor is less than the saturation concentration at a dew point of 8 ° C.

  As a method for analyzing the sample gas of the present invention, a part of the sample gas is fractionated, the sample gas is diluted with a dilution gas to an appropriate dilution factor, and the mercury concentration in the diluted sample gas is measured. The so-called batch analysis method, sample gas is collected, an appropriate dilution ratio with the dilution gas is determined, a sample gas diluted with the determined dilution ratio is prepared, and the mercury in the diluted sample gas is prepared. When a change in mercury concentration occurs during the so-called continuous analysis method that continuously measures the concentration, and in this way continuously analyzing the mercury concentration in the diluted sample gas In preparation, if it is necessary to change the dilution rate of the sample gas based on the analysis result and change the dilution rate, determine the dilution rate again and prepare the sample gas diluted to the determined dilution rate And this diluted sample gas Repeated again continuously measuring the mercury concentration is continuous analysis. The apparatus of the present invention is a gas analyzer configured so that analysis can be performed by each of these analytical methods, and a measurement gas is prepared by separating a part of a sample gas and mixing and diluting with a dilution gas. The first preparation unit part to be prepared, the second preparation unit part to prepare the measurement gas by continuously mixing and diluting the dilution gas without separating the sample gas, and the mercury concentration in the measurement gas And a measurement unit that measures the water vapor concentration in the sample gas, and a dilution rate control unit that verifies the dilution rate based on the measurement result and controls the dilution rate.

First, the gas analyzer of the present invention will be specifically described with reference to FIG.
FIG. 1 is a block diagram showing an outline of the analyzer of the present invention. In the figure, solid arrows indicate the flow of gas, and dotted arrows indicate the flow of information such as measured values and control signals. The gas flows in a conduit or pipe indicated by a solid line, but the conduit or pipe indicated by reference numeral 2 is a heating conduit 2 that is heated and kept warm, and moisture and mercury are aggregated in the conduit. In order to prevent this, it is heated and kept at a temperature of 130 ° C. or higher. On the other hand, the conduit or pipe to which reference numeral 3 is assigned is the exhaust pipe 3, which is the remaining pipe after obtaining the measurement gas necessary for analyzing mercury or the like in the sample gas. It is a pipe for passing and exhausting gas. It is not always necessary to heat and keep at a temperature of 130 ° C. or higher in order to prevent moisture and mercury from aggregating in the conduit. It is preferable to heat and keep the temperature in the same manner as the heating conduit in order to prevent deposits and the like from being hindered. As shown in FIG. 1, the heating conduit 2 and the exhaust pipe 3 are connected to each other, and are, for example, conduits with a built-in heater that are commercially available for sampling exhaust gas. It is possible to use a heating device such as a ribbon heater attached to a normal conduit. In addition to directly heating and keeping the conduit with a heater, the inside of the device where the conduit is located is heated and kept warm. By doing so, the conduit may be heated and kept warm. As the material of the conduit, as described in JIS K0095, for example, borosilicate glass, silica glass, stainless steel, tetrafluoroethylene resin, and hard vinyl chloride resin are heat resistant and corrosion-resistant. And from the viewpoint of preventing the adhesion of mercury.
Further, the temperature of the heating conduit of 130 ° C. or higher is a temperature exceeding the saturation temperature of 123 ° C. at the maximum mercury concentration of 10 g / m ³ that can be measured by the present invention, and this prevents condensation of mercury in the apparatus. In order to reliably prevent mercury condensation, the temperature is preferably set to 180 ° C. or higher.

  Moreover, as described above, the gas analyzer includes the first preparation unit for preparing the diluted measurement gas, the second preparation unit for continuously preparing the diluted measurement gas, and the measurement unit. Among these, the first preparation unit part flows from the gas sampling part 1 to the gas fractionator 10, and the gas fractionator 10 Dilution gas is introduced from the lower side of the gas preparator 10 which is a flow path in a state where the function is exhibited, and the gas is mixed from the heating conduit 2 led out from the right side of the gas preparator 10 via the mass flow controller 22 The path leading to the container 7 corresponds, and the second preparation unit section flows from the gas sampling section 1 to the gas fractionator 10 and the flow path in which the sample gas flows in the gas fractionator 10 Is a gas fractionator Is introduced from the left side of 0, in which heating conduit 2 which is derived from the upper side of the winding machine 10 gas partial, the path leading to the gas mixer 7 through a mass flow controller 22 corresponds. On the other hand, the measurement unit section corresponds to the mercury analyzer 11, the moisture concentration detection means 40, the temperature detection means 24, and the like, and the dilution rate control unit section corresponds to the calculator 50, the controller 51, the mass flow controller 22, and the like. doing.

  By the way, in the gas analyzer of the present invention, for example, a pump 30 is provided with a part of the exhaust gas as a sample gas in the apparatus from the gas sampling unit 1 installed in a flue of exhaust gas containing mercury and heated and kept warm. It is pulled in by the suction power of. At this time, the drawn sample gas is preferably passed through the filter 5 to remove impurities (for example, solid particles) in the sample gas.

  The sample gas that has passed through the filter 5 flows through the heating conduit 2 and is introduced into the gas fractionator 10 from the left side, and the sample gas that passes through the gas fractionator 10 is connected to the upper side of the gas fractionator 10. To the heating conduit 2 and exhausted to the gas exhaust section 4 by the pump 30 via the exhaust pipe 3 or from the heating conduit 2 branched downward by switching the flow path, the gas flow controller 22 and the gas It flows to the mixer 7. This flow is used for the preparation of the measurement gas used for the continuous analysis diluted with the fixed dilution rate described later, and corresponds to the second preparation unit. The sample gas to be exhausted is purified as necessary, and finally exhausted as a clean gas from which mercury or the like is removed.

  On the other hand, when part of the sample gas is separated by the gas sorter 10, the flow path of the gas sorter 10 is changed from (left → upper) to (lower → right). As a result, a part of the sample gas is separated, and the separated sample gas is supplied to the heating conduit 2 on the right side of the gas separator 10 together with the dilution gas introduced from the lower side of the gas separator 10. Then, it is derived and introduced into the gas mixer 7 via the mass flow controller 22. This flow constitutes the first preparation unit.

A part of the sample gas flowing through the heating conduit 2 and passing through the filter 5 from the gas sampling part is branched downward from the heating conduit 2 and is sampled by the moisture concentration measuring device which is the moisture concentration detecting means 40. The water vapor concentration in the gas is measured, and the sample gas after measurement flows through the exhaust pipe 3 to the gas exhaust unit 4 by the pump 30 and is exhausted outside the apparatus. As described above, the sample gas to be exhausted is purified as necessary, and finally exhausted as a clean gas from which mercury or the like is removed.
In addition, as the pump 30, a commercially available thing can be used, for example, a diaphragm type air pump etc. can be used. Further, as the moisture concentration detecting means 40, a commercially available temperature / humidity meter, moisture concentration measuring device, or the like can be used.

  Next, fractionation of the sample gas by the gas fractionator 10 will be described. As described above, the sample gas sampled by the gas sampling unit 1 is introduced into the gas sorter 10 through the heating conduit 2. The gas fractionator 10 is for collecting a part of the sample gas and preparing a measurement gas, and may be of any type as long as a part of the sample gas can be fractionated. . For example, in the case of a gas sorter 10 of a type in which the gas flow path as shown in FIG. 1 is changed and sorted, it is introduced into the gas sorter 10 from the left side of the gas sorter 10. The sample gas passes through the gas separator 10, whereby the sample gas is stored in the gas separator 10, while the gas that has passed passes through the heating conduit 2 installed above the gas separator 10 and the heating pipe 2. The gas passes through the exhaust pipe 3 and is exhausted by the pump 30 to the gas exhaust unit 4. The sample gas stored in the gas preparator 10 is separated by changing the gas flow path of the gas preparator 10 and communicating with the heating conduit 2 on the right side of the gas preparator 10. . That is, by changing the flow path in the gas sorter 10, the dilution gas is heated from the heating conduit 2 disposed below the gas sorter 10 via the dilution gas heater 23. The diluted gas is introduced, and the sample gas stored in the gas sorter 10 by the diluted gas is discharged to the heating conduit 2 arranged on the right side of the gas sorter 10. As a result, a part of the sample gas can be collected, and the collected sample gas is used as a reference for measuring the concentration of mercury or the like and determining the dilution rate with the dilution gas.

  Next, the sample gas separated by the gas separator 10 and flowing out from the heating conduit 2 on the right side of the gas separator 10 is introduced into the gas mixer 7 through the mass flow controller 22 together with the heated dilution gas. On the other hand, if necessary, the dilution gas introduced from the left side of the gas mixer 7 is mixed and diluted by the gas mixer 7 to prepare a measurement gas.

  On the other hand, the dilution gas is introduced from the dilution gas introduction pipe 6 and preferably passes through, for example, a dehumidifier 20 filled with silica gel, molecular sieve, calcium chloride, quicklime, etc., and an adsorption removal device 21 filled with, for example, activated carbon. In addition, moisture, impurities, and the like are removed, the flow rate is adjusted by the mass flow controller 22, and the dilution gas heater 23 is used to increase the temperature of the dilution gas so that the temperature of the sample gas does not decrease. Then, the gas is introduced into the gas separator 10 from the lower side of the gas separator 10. When the flow path of the gas preparator 10 is open, the introduced dilution gas passes through the gas preparator 10 from the heating conduit 2 on the right side of the gas preparator 10 via the mass flow controller 22. Guided to the mixer 7. Of course, the flow path of the dilution gas is used when the gas preparator 10 allows the sample gas to flow from the heating conduit 2 on the left side of the gas preparator 10 to the heating conduit 2 provided on the upper side. The gas flow path is closed. Nitrogen, helium, pure air, or the like may be used as the dilution gas, but air is preferable in terms of versatility and operating cost.

  The diluent gas introduced into the gas mixer 7 is a heated diluent gas that passes through the gas preparator 10 and is provided on the left side of the gas mixer 7 in accordance with the dilution factor and the like. A dilution gas can be newly introduced through the flow path, and these gases can be mixed and diluted to prepare a measurement gas. The dilution gas introduced from the left side of the gas mixer 7 used here may be a dilution gas that is not heated, but is heated to a required temperature via a dilution gas heater (not shown). A dilution gas may be used.

  As the mass flow controller 22 that can be used, a commercially available one can be used. The mass flow controller measures the flow rate of the flowing gas, and according to the flow rate, a flow rate adjusting device such as an electromagnetic valve provided in the mass flow controller. The gas flow rate is controlled. Further, as the gas mixer 7 that can be used, a commercially available so-called static mixer can be used. The gas can be combined and mixed by combining with a mold.

  The gas mixer 7 mixes and dilutes a part of the sample gas separated by the gas separator 10 with a heated dilution gas or a heated dilution gas and an unheated dilution gas. The prepared gas is prepared as a measurement gas. The prepared measurement gas is introduced into the mercury analyzer 11 through the measurement gas introduction pipe 8 arranged on the right side of the gas mixer 7 and the mercury concentration is measured. The measured measurement gas introduced into the mercury analyzer 11 and discharged from the mercury analyzer 11 is exhausted from the gas exhaust unit 4 by the pump 30 via the adsorption removal device 21 filled with activated carbon and the mass flow controller 22. The The exhaust pipe 3 branched from the measurement gas introduction pipe 8 and led to the pump 30 is an exhaust pipe for bypassing the mercury analyzer 11 and is configured to be exhausted from the gas exhaust unit 4 by the pump 30. Yes. The measurement gas bypassing the mercury analyzer 11 to be exhausted is finally exhausted as a clean gas from which mercury or the like is removed as necessary, as described above.

  The mercury analyzer 11 can be generally performed by flowing a measurement gas diluted in an analysis cell and measuring the absorbance and the amount of fluorescence using an atomic absorption method or an atomic fluorescence method. A commercially available mercury analyzer can also be used. For example, a mercury analyzer AM-3 manufactured by Japan Instruments Co., Ltd. can be suitably used. Thus, when using a commercially available mercury analyzer, it can utilize as a pre-processing apparatus for introduce | transducing the measuring gas diluted to this mercury analyzer.

  In the present invention, based on the mercury concentration in the measurement gas measured by the mercury analyzer 11 and the water vapor concentration in the sample gas, the sample gas is diluted with the dilution gas to a predetermined dilution factor. This dilution factor is adjusted so that the concentration of mercury in the measurement gas and the concentration of water vapor in the sample gas are less than the saturation concentration of 8 ° C. dew point. For this adjustment, the gas analyzer of the present invention has a computing unit 50 as verification means for verifying the dilution rate and a controller 51 as control means for adjusting the dilution rate. The controller 51 includes, for example, mercury concentration information from the mercury analyzer 11, temperature information from the thermometer that is the temperature detection means 24 (such as a 1 to a 3), and water vapor concentration from the moisture concentration measuring device that is the moisture concentration detection means 40. By receiving information (d) and the like and sending control signals (b1 to b3) to the mass flow controller 22 and the flow rate control valve, the desired dilution ratio and finally mercury and water vapor in the diluted measurement gas The flow rate of each gas (sample gas, dilution gas, measurement gas) is adjusted so that the concentration of the gas is less than the saturation concentration at a dew point of 8 ° C. Further, the computing unit 50 calculates the mercury concentration in the sample gas from the result of the mercury concentration in the measurement gas, the water vapor concentration in the sample gas, the dilution rate, and the like, and displays the result on the display unit 52.

  In addition, for the verification of the dilution rate by the computing unit 50, the measurement result of the mercury concentration in the measurement gas and the measurement result of the water vapor concentration in the sample gas are used. In the case of the mercury concentration, for example, in the measurement gas If the mercury concentration measurement result shows a range (scale over) exceeding the measurement range of the mercury analyzer 11 or a high value such as 90% or more of the measurement range, the dilution factor is inappropriate. The controller 51 is instructed to increase the dilution factor. On the other hand, when the measurement result of the mercury concentration in the measurement gas is not detected by the mercury analyzer 11 or when only a low value such as 10% or less of the measurement range is shown, the dilution factor is inappropriate. Is determined, and the controller 51 is instructed to reduce the dilution factor. Except in these cases, the dilution factor is determined to be appropriate. Then, since the sample gas is diluted to prevent condensation of mercury and water vapor in the measurement gas, it is determined whether or not the concentration of mercury and water vapor in the measurement gas is equal to or lower than the saturation concentration of 8 ° C. dew point. It is finally determined as a reference, and the appropriateness of the dilution rate is determined.

  The water vapor concentration in the measurement gas can be obtained from the water vapor concentration in the sample gas. The water vapor concentration detecting means (not shown) for directly measuring the water vapor concentration in the measurement gas is provided. Also good. Moreover, in order to ensure that the temperature of the sample gas before preparing the measurement gas is 130 ° C. or higher, a thermometer for measuring the temperature of each gas (sample gas, dilution gas, measurement gas) It is preferable to provide the temperature detection means 24 as described above and send the measurement result to the calculator 50 (a1 to a3) to be used for the control of the mass flow controller 22.

  In the gas analyzer of the present invention, the concentration of mercury and water vapor in the measurement gas is adjusted to a concentration lower than the saturation concentration with a dew point of 8 ° C., which is commercially available. This is to prevent condensation of mercury and water vapor in the measurement gas during analysis, taking into account the use of a mercury analyzer.

  Next, a description will be given of a case where the measurement gas is continuously prepared so that the dilution rate of the sample gas is determined to be appropriate and the determined dilution rate is obtained. For the preparation of the measurement gas, the gas in the gas fractionator 10 flows upward from the left side of the gas fractionator 10 and is derived using a flow path through which the sample gas passes in the gas fractionator 10. The coming sample gas is introduced into the gas mixer 7 via the mass flow controller 22. In the gas mixer 7, the dilution gas introduced into the gas mixer 7 from the left side of the gas mixer 7 is mixed and diluted at a specific dilution ratio to prepare a measurement gas, and the prepared measurement gas is used. Then, the mercury concentration in the measurement gas is continuously measured by the mercury analyzer 11.

  Further, in the apparatus of the present invention, heating and heat insulation branching from the heating conduit 2 upstream of the gas fractionator 10, bypassing the gas fractionator 10, and communicating with the gas mixer 7 via the mass flow controller 22. It is preferred to provide a heated heating conduit 2. With this heating conduit 2, it is possible to continuously prepare a measuring gas having a determined dilution ratio.

  The heating conduit 2 that branches from the heating pipe 2 from the gas sampling section 1 upstream of the gas separator 10, bypasses the gas separator 10, and flows to the gas discharge section 4 is generally connected to the gas separator 10. In order to prevent the sample gas from flowing through the gas separator 10 or to adjust the flow rate flowing through the gas preparator 10, the heating conduit 2 is branched downward while flowing into the gas exhaust section 4, and the heating conduit 2 As described above, the measurement gas can be prepared by the gas mixer 7 by being guided to the gas mixer 7 via the mass flow controller 22. In this case, when the measurement gas is prepared, the gas fractionator 10 is not used for supplying the sample gas. Therefore, the dilution gas is mixed into the gas mixer using the flow path through which the dilution gas of the gas fractionator 10 flows. The gas for measurement can be prepared by the gas mixer 7 in combination with the diluent gas introduced from the left side of the gas mixer 7. As a dilution gas used for dilution, a heated gas or a non-heated gas may be used depending on the dilution factor. Of these methods of preparing the measurement gas, which method to prepare is appropriately selected depending on, for example, mercury concentration, water vapor concentration, dilution rate, gas flow rate, and the like.

Next, a method for analyzing gas using the gas analyzer of the present invention will be described. As described above, the method for analyzing the sample gas includes a so-called batch analysis method, a so-called continuous analysis method, and a continuous analysis method.
Among these, the so-called batch analysis method basically collects a part of a sample gas and mixes it with a dilution gas at a provisional dilution ratio to prepare a measurement gas. The dilution rate is determined while verifying the dilution rate with the dilution gas based on the mercury concentration and the like, and the mercury concentration in the sample gas diluted at this dilution rate is measured.
In addition, the so-called continuous analysis method can determine the dilution ratio without using a part of the sample gas separated by the gas fractionator after the dilution ratio is determined and the dilution ratio is determined in this way. Thus, the sample gas and the dilution gas are continuously mixed and diluted to prepare a diluted measurement gas, and the mercury concentration in the measurement gas is continuously measured.
Furthermore, the continuous analysis method verifies the dilution ratio from the mercury concentration measurement results when the mercury concentration changes while the mercury concentration is continuously measured by the continuous analysis method. If necessary, a new dilution ratio is determined again using a part of the sample gas collected by the gas separator, and the sample gas and the dilution gas are continuously mixed at this determined dilution ratio. Thus, the measurement gas is prepared, and the mercury concentration in the prepared measurement gas is continuously measured again. Hereinafter, each analysis method will be specifically described with reference to FIG.

  In the so-called batch analysis method, a dilution rate is provisionally determined for analysis, and then a sample gas is sampled from the gas sampling unit 1 and a part of the sample gas sampled by the gas preparator 10 is sampled. To tentatively determine the dilution factor, it is possible to determine the dilution factor in advance so that the mercury concentration is less than the saturation concentration with a dew point of 8 ° C. if an approximate estimate such as the mercury concentration in the exhaust gas is obtained. If the mercury concentration in the exhaust gas is unknown, an arbitrary magnification is determined for the time being.In the present invention, first, the mercury concentration is measured by the determined dilution magnification, and the dilution magnification is verified. Since the dilution ratio is prepared sequentially and the appropriate dilution ratio is determined, an arbitrary dilution ratio such as 2000 times, 5000 times, or 10000 times is determined at the beginning of the measurement.

  Next, the flow path of the gas preparator 10 is converted in order to collect a part of the sample gas. Thereby, the sample gas fractionated by the gas fractionator 10 is guided toward the gas mixer 7 together with the dilution gas introduced into the gas fractionator 10, and the gas mixer 7 is separately provided as necessary. In addition, the measurement gas is prepared by mixing and diluting these gases with the gas mixer 7 so as to achieve the provisional dilution ratio described above. Get gas. Next, the obtained measurement gas is guided to the mercury analyzer 11 to measure the mercury concentration in the measurement gas, and diluted by the measured mercury concentration in the measurement gas and the water vapor concentration in the sample gas. The calculator 50 verifies whether the magnification is appropriate. Next, as a result of verifying the dilution rate, if it is determined that the dilution rate is inappropriate, the controller 51 sets the dilution rate of the sample gas so that the mercury and water vapor concentrations are less than the saturation concentration at the dew point of 8 ° C. The controller 22 adjusts the flow rate and the like, prepares the measurement gas with the adjusted dilution rate, measures the mercury concentration in the obtained measurement gas, and verifies the dilution rate. This verification and preparation of the dilution ratio are repeated until the dilution ratio is determined to be appropriate, and the mercury concentration in the measurement gas and the water vapor concentration in the sample gas are calculated based on the dilution ratio determined to be appropriate. The resulting mercury concentration in the exhaust gas is displayed.

  Here, the dilution rate is adjusted such that the dilution rate of the sample gas is adjusted by the dilution rate control means 51 via the mass flow controller 22 so that the concentration of mercury and water vapor is less than the saturated concentration of 8 ° C. In this adjustment, the dilution factor may be changed in stages, and the dilution factor may be verified each time. Alternatively, the dilution factor that is less than the saturation concentration at a dew point of 8 ° C may be obtained by one change. it can.

  Next, in the so-called continuous analysis method, the measurement gas is prepared by mixing and diluting the sample gas and the dilution gas at the dilution rate determined and determined as appropriate as described above. Continuously measure mercury concentration.

  The measurement gas is prepared by continuously obtaining a sample gas through a flow path that passes through the gas sorter 10 and is introduced into the gas sorter 10 from the left side of the gas sorter 10 and led out to the upper side. By introducing the gas to the gas mixer 7 via the mass flow controller 22 by the heating conduit 2, it is possible to obtain a measurement gas diluted to a specific dilution factor. In this case, a dilution gas introduced from the left side of the gas mixer 7 is used as a dilution gas for dilution, and this dilution gas is a dilution gas heated by a dilution gas heater (not shown). In addition, whether to heat or not is determined from, for example, the dilution rate and the gas flow rate.

  On the other hand, the measurement gas can be prepared by using a route that does not pass through the gas preparator 10, unlike the above-described preparation method. That is, the sample gas sampled by the gas sampling unit 1 is branched from the heating conduit 2 that flows to the gas fractionator 10 (from the heating conduit 2 that is introduced to the left side of the gas fractionator 10 and is branched upward). The measurement gas is prepared by using a route led to the heating conduit 2), the mass flow controller 22, and the gas mixer 7.

  By this route, the sample gas is continuously introduced into the gas mixer 7 via the mass flow controller 22 without going through the gas preparator 10. In this case, since the gas preparator 10 is not used for supplying the sample gas, the dilution gas mixed and diluted with the sample gas is introduced from the lower side of the gas preparator 10 (through the gas preparator 10). Then, it is supplied from the flow path of the heated dilution gas discharged from the right side) and introduced into the gas mixer 7 together with the sample gas via the mass flow controller 22 to prepare the measurement gas. On the other hand, without using such a route through the gas sorter 10, the gas is supplied from a dilution gas introduced from the left side of the gas mixer 7 or, if necessary, from these two channels. A gas for measurement is prepared by mixing and diluting the sample gas at a predetermined dilution ratio by the gas mixer 7 using the two dilution gases. The dilution gas used for the preparation of the measurement gas may be heated or not heated, and is selected according to the dilution factor, gas flow rate, and the like.

  As described above, when preparing the measurement gas for the continuous analysis method, the gas is prepared by the flow path that passes through the gas preparator 10 or the flow path that does not pass through the gas preparator 10 Whether the gas for measurement is prepared is adjusted by each valve provided in the heating conduit 2. Which path is used to prepare the measurement gas is appropriately selected according to the dilution factor, the gas flow rate, and the like.

  Nitrogen, helium, pure air, etc. can be used as a dilution gas for diluting the sample gas, but it is preferable to use air in terms of versatility and operating cost, and the flow rate of the diluted gas introduced is diluted. It is controlled by a mass flow controller 22 provided in the gas flow path. In addition, as this dilution gas, it is preferable to use what was refine | purified through the dehumidifier 20 or the adsorption removal apparatus 21, for example.

  Next, the mercury concentration in the measurement gas prepared at a predetermined dilution ratio is measured by the mercury analyzer 11, and the mercury concentration is calculated from the mercury concentration in the obtained measurement gas and the water vapor concentration in the sample gas. 50, and the mercury concentration in the exhaust gas is displayed on the display 52.

In the continuous analysis method, when the mercury concentration in the exhaust gas is continuously measured in this way, if the mercury concentration in the exhaust gas fluctuates, the dilution factor is changed and the mercury concentration is measured again. It is a gas analysis method that continues.
When the mercury concentration is measured continuously as described above, when the mercury concentration in the exhaust gas to be measured fluctuates, it is necessary to change the dilution factor according to the fluctuation of the mercury concentration. Arise. That is, when it is verified that the dilution ratio needs to be changed due to the result of continuously measuring mercury concentration or the like, the gas fractionator 10 is used again by the same process as the batch analysis method described above. A sample gas is collected and mixed with the dilution gas to prepare a measurement gas. The dilution factor is verified by the mercury concentration in the measurement gas and the water vapor concentration in the sample gas, and if necessary Then, the dilution rate of the sample gas is adjusted by the dilution rate control means 51 via the mass flow controller 22 so that the concentration of mercury and water vapor is less than the saturation concentration of 8 ° C., and a new dilution rate is obtained. Confirmed. In the same manner as the above-mentioned continuous analysis method, the sample gas and the dilution gas are mixed with the gas mixer 7 by either the method of passing the gas fractionator 10 or not using the determined dilution ratio. This is an analysis method in which a measurement gas is prepared by mixing and diluting by the above, and the mercury concentration in the measurement gas is continuously measured again.

  In addition, as the exhaust gas containing mercury that is an object of gas analysis to which the present invention is applied, for example, solid substances such as dust, sludge and minerals containing mercury, and solid substances such as glass tubes to which mercury-containing substances are attached are used. Exhaust gas generated when heated. In addition, when measuring the exhaust gas, even if the mercury concentration in the exhaust gas is high or temporarily high, it is measured after diluting as appropriate. The mercury concentration can be measured, and the mercury concentration in such exhaust gas can be continuously measured and monitored. Furthermore, even if the mercury concentration in the exhaust gas changes, the dilution factor is changed again according to the change, and the mercury concentration is measured under this changed dilution factor. Measurement and monitoring of mercury concentration can be continued.

  The gas analyzer and the analysis method have been described in detail above. However, the gas analyzer and the analysis method of the present invention are not limited to the above description, and changed specifications are within the scope of the invention. It goes without saying that it is possible.

About the dilution rate at the time of measuring the mercury concentration in exhaust gas using the analyzer and analysis method of this invention, it calculates | requires as follows.
For example, if the mercury concentration in the sample gas is 10 g / m ³ , this mercury concentration 10 g / m ³ is a saturation temperature of a dew point of 123 ° C., and by diluting the sample gas 2100 times, the mercury concentration is set to a dew point of 8 It can be less than the saturation concentration of ° C.
Moreover, since the measurement range of a mercury analyzer such as a mercury survey meter (for example, EPM-2 manufactured by Nippon Instruments Co., Ltd.) is generally 0 to 0.9999 mg / m ³ , the mercury analyzer can measure the amount of mercury. When the dilution ratio is calculated on the basis of the concentration, a dilution of 10500 times or more is required. And in order to obtain | require the mercury concentration in waste gas appropriately as a measured value of about 90% (about 90% of full scale) of the measuring range of a measuring apparatus, sample gas will be diluted 12000 times.

The present invention, which can measure precisely the concentrations of the measurement range the range of 1μg / m ³ ~5mg / m ³ outperform 1μg / m ³ ~10g / m ³ defined by the continuous measurement of JIS K0222 is there. Accordingly, it is possible to accurately measure the mercury concentration of exhaust gas generated when heating dust containing mercury, which has been difficult to measure in the past, and to use the analysis results for process control. The method becomes an industrially effective technology. In addition, for mercury analysis, a mercury analyzer pretreatment device that has already been commercialized, that is, a gas containing high-concentration mercury is diluted into a measurement gas that contains a mercury content within a measurable range. It is also an effective technique because it can be used as an apparatus for preparation and can measure a wide range of mercury concentrations using a commercially available mercury analyzer.

DESCRIPTION OF SYMBOLS 1 Gas sampling part 2 Heating pipe 3 Exhaust pipe 4 Gas exhaust part 5 Filter 6 Dilution gas introduction pipe 7 Gas mixer 8 Measurement gas introduction pipe 10 Gas sorter 11 Mercury analyzer 20 Dehumidifier 21 Adsorption removal apparatus 22 Mass flow controller 23 Dilution gas heater 24 Temperature detection means 30 Pump 40 Moisture concentration detection means 50 Calculator 51 Controller 52 Display

Claims (4)

A gas analyzer including mercury and water vapor,
A gas sampling section for collecting a sample gas containing mercury and water vapor while heating and keeping the mercury and water vapor in a gaseous state;
A heating conduit that keeps the sample gas collected in the gas sampling section flowing and kept warm,
A heated and insulated gas fractionator that fractionates a portion of the sample gas flowing through the heating conduit;
A dilution gas introduction pipe for introducing a dilution gas for diluting the sample gas collected, and
A dilution gas heater for heating the introduced dilution gas;
A heating conduit that introduces a heated dilution gas into the gas fractionator, and a heated heating conduit;
The sample gas collected by the gas separator, the dilution gas introduced into the gas separator, and a separate dilution gas are introduced if necessary, and these gases are mixed to form a diluted measurement gas. A gas mixer to
Moisture concentration detection means for measuring the water vapor concentration in the sample gas;
A mercury analyzer for measuring the mercury concentration in the diluted measuring gas;
A verification means for verifying the dilution ratio with the dilution gas based on the measurement result of the mercury concentration in the measurement gas and the measurement result of the water vapor concentration in the sample gas;
A control means for adjusting the dilution rate of the sample gas so that the concentration of mercury and water vapor in the diluted measurement gas is less than the saturation concentration at a dew point of 8 ° C .;
Calculation means for calculating the mercury concentration in the sample gas from the measurement result of the mercury concentration in the obtained measurement gas, the measurement result of the water vapor concentration in the sample gas, and the dilution factor;
Based on the obtained calculation results, an indicator that displays at least mercury concentration,
A gas analyzer comprising: A method for analyzing a gas containing mercury and water vapor,
A step of tentatively determining a dilution ratio that is a mixing ratio of the sample gas and the dilution gas;
Sampling the sample gas in the gas sampling section while heating and keeping the mercury and water vapor in a gaseous state; and
Heating the sample gas sampled in the gas sampling section and flowing it through a heated heating conduit;
A part of the sample gas flowing in the heating conduit is heated and separated by a heated gas fractionator;
The heated dilution gas is introduced into the gas preparator, the sample gas separated by the gas preparator, the dilution gas introduced into the gas preparator, and a separate dilution gas as necessary are introduced. To obtain a measurement gas diluted at a provisional dilution ratio,
Measuring the mercury concentration in the measurement gas;
Separately measuring the water vapor concentration in the sample gas;
A step of verifying the dilution rate based on the water vapor concentration in the obtained sample gas and the mercury concentration in the measurement gas;
A dilution ratio control step of adjusting the dilution ratio of the sample gas so that the concentration of mercury and water vapor is less than the saturation concentration at a dew point of 8 ° C., when the obtained verification result indicates that the dilution ratio is inappropriate.
Prepare a measurement gas with the adjusted dilution ratio, measure the mercury concentration in the measurement gas, repeat the process of verifying the dilution ratio, and determine that the dilution ratio is appropriate based on the verification results obtained. A calculation step for calculating the mercury concentration from the measurement result of the mercury concentration in the obtained measurement gas, the measurement result of the water vapor concentration in the sample gas, and the dilution factor;
A step of displaying at least mercury concentration based on the obtained calculation result;
Gas analysis method having A method for analyzing a gas containing mercury and water vapor,
A step of tentatively determining a dilution ratio that is a mixing ratio of the sample gas and the dilution gas;
Sampling the sample gas in the gas sampling section while heating and keeping the mercury and water vapor in a gaseous state; and
Heating the sample gas sampled in the gas sampling section and flowing it through a heated heating conduit;
A part of the sample gas flowing in the heating conduit is heated and separated by a heated gas fractionator;
The heated dilution gas is introduced into the gas preparator, the sample gas separated by the gas preparator, the dilution gas introduced into the gas preparator, and a separate dilution gas as necessary are introduced. To obtain a measurement gas diluted at a provisional dilution ratio,
Measuring the mercury concentration in the measurement gas;
Separately measuring the water vapor concentration in the sample gas;
A step of verifying the dilution rate based on the water vapor concentration in the obtained sample gas and the mercury concentration in the measurement gas;
A dilution ratio control step of adjusting the dilution ratio of the sample gas so that the concentration of mercury and water vapor is less than the saturation concentration at a dew point of 8 ° C., when the obtained verification result indicates that the dilution ratio is inappropriate.
Prepare the measurement gas with the adjusted dilution ratio, repeat the process of verifying the dilution ratio by measuring the mercury concentration in the measurement gas,
If it is determined that the dilution ratio is appropriate based on the obtained verification result, a step of determining the dilution ratio;
A step of continuously obtaining a sample gas for dilution without diluting a part of the sample gas with a gas fractionator when diluting the sample gas in accordance with the determined dilution factor;
Introducing a dilution gas into the obtained sample gas and mixing with a gas mixer to obtain a measurement gas with a determined dilution factor;
A step of continuously measuring the mercury concentration in the measurement gas with the obtained measurement gas;
A calculation step of calculating the mercury concentration from the measurement result of the mercury concentration in the obtained measurement gas, the measurement result of the water vapor concentration in the sample gas, and the dilution factor;
A step of displaying at least mercury concentration based on the obtained calculation result;
Gas analysis method having   The method further includes the step of verifying the dilution factor based on the water vapor concentration in the sample gas prepared according to the determined dilution factor and the mercury concentration in the measurement gas, and the sample gas dilution factor is determined based on the verification result. The gas of claim 3, comprising a step of changing the dilution rate by adjusting, obtaining a measurement gas having the changed dilution rate, and continuously measuring again the mercury concentration in the obtained measurement gas. Analysis method.

Images