JP2007248114A - Gas analyzer - Google Patents

Abstract

Provided is a gaseous organic compound analyzer suitable for performing on-line analysis of organic compounds in gas easily and quickly while maintaining accuracy by switching exhaust gas and air lines at multiple locations continuously. To do.
SOLUTION: A plurality of sampling nozzles for introducing a sample gas such as an exhaust gas or the atmosphere of a combustion furnace, an organic compound decomposition treatment plant, etc., a plurality of pipes for introducing the sample gas from the nozzles, a front stage or a rear stage of the pipes A plurality of filters for removing ash and dust in the sample gas, a line switching device for switching the plurality of sample gas lines, and analyzing organic compounds in the sample gas selected by the line switching device A direct mechanism for directing the sample gas selected by the line switching device to the analytical device and an adsorption / desorption device for concentrating and desorbing organic compounds. A mechanism is provided so that the direct mechanism and the adsorption / desorption mechanism can be arbitrarily switched.
[Selection] Figure 2

Description

  The present invention efficiently and continuously removes harmful organic compounds such as exhaust gas discharged from combustion furnaces, organic compound decomposition treatment plants, etc. or atmospheric dioxins, aromatics and the like without being affected by other contaminant components. The present invention relates to a gas analyzer for analysis, and more particularly to a gas analyzer suitable for so-called on-line analysis in which analysis results are transmitted via communication means.

  Dioxin emission regulation in incinerator exhaust gas is regulated by the Waste Disposal Law revision (H14 / 12/1), and further PCB decomposition due to the total abolition of PCB by "Special Measures Law on Promotion of Proper Treatment of PCB Waste" A processing plant has been built and processing has started.

  In line with this trend, it is necessary to regularly monitor whether the concentration of exhausted gas, processing gas, and gasified hazardous organic compounds in the work environment is regulated within the regulations. Since the regulation value is expected to decrease in the future, an apparatus for analyzing the above substances quickly and with high accuracy is desired.

Traditionally, as an online continuous analyzer for dioxin precursors,
Patent Document 1 describes a method for continuously measuring dioxin precursors and the like in exhaust gas with high accuracy online.

Japanese Patent No. 3654046

  However, in the gas analyzer described in Patent Document 1, there is only one measurement line, and no particular mention is made regarding the contaminated components other than hydrogen sulfide and hydrogen chloride. Depending on the concentration of the component, the sensitivity of the analyzer may decrease.

  An object of the present invention is to provide a gaseous organic compound analyzer suitable for analyzing organic compounds in a gas simply, quickly, and efficiently while maintaining accuracy by continuously switching exhaust gas and air lines at a plurality of locations. Is to provide.

  The gaseous organic compound analyzer of the present invention includes a plurality of sampling nozzles for introducing a sample gas such as an exhaust gas or the atmosphere of a combustion furnace or an organic compound decomposition treatment plant, and a plurality of pipes for introducing the sample gas from the nozzles. A plurality of filters for removing ash and dust in the sample gas disposed in the front stage or the rear stage of the pipe, a line switching device for switching the plurality of sample gas lines, and the sample gas selected by the line switching device An analysis device for analyzing the organic compounds in the inside, and a direct mechanism for directing the sample gas selected by the line switching device directly to the analysis device, and an absorption device for concentrating and desorbing the organic compounds. An adsorption / desorption mechanism led to the desorption device is provided, and the direct mechanism and the adsorption / desorption mechanism can be switched arbitrarily. To.

  According to the present invention, gaseous organic compound analysis suitable for online analysis of an organic compound in a gas simply and quickly while maintaining accuracy is achieved by continuously switching exhaust gas and air lines at a plurality of locations. A device can be obtained.

  In the case where a plurality of lines for introducing the analysis target gas into the analyzer are provided and measurement is performed by switching them, the configuration shown in FIG. 1 can be considered.

  As a configuration, the plurality of sampling units 100a, 100b, 100c for introducing the sample gas from the flue 1a, 1b, 1c, the plurality of introduction pipes 4a, 4b, 4c for introducing the sample gas, and the introduced gas are switched. It comprises a pre-processing unit 200 and an analyzer 300 that analyzes the switched gas.

  Sampling units 100a, 100b, and 100c are composed of sampling nozzles 2a, 2b, and 2c and dust filters 3a, 3b, and 3c. The pre-processing unit 200 includes suction pumps 6a, 6b, and 6c for sucking sample gas, and an arbitrary line. Valves 10a, 10b, and 10c for switching and opening and closing, and flow meters 7a, 7b, and 7c as necessary are provided. The analyzer 300 includes an analysis unit 310 such as a mass spectrometer, a flow meter 320, and a suction pump 330.

  As an operation, the sample gas of each line is always drawn by the flow meter 7 by the constant flow rate suction pumps 6a, 6b, 6c. The valve (for example, 10a) only for the line to be measured is opened, and the other valves (10b, 10c) are closed.

  The measurement gas is guided to the analysis unit 310 by the suction pump 330 through the open valve 10a and analyzed. Similarly, by switching the valve 10b of the other line to be measured and closing the other valve 10a or 10c, the measurement can be performed by switching.

  FIG. 5 shows a switching sequence by direct measurement. Even with this method, measurement can be performed by switching a plurality of lines. However, in order to perform direct measurement, there may be a case where a line that cannot be measured due to a decrease in sensitivity of the analyzer is generated due to a contamination component of each line.

  An improved configuration for solving the problem is shown in FIG.

  This apparatus was mainly introduced with a plurality of sampling units 100a, 100b, 100c for introducing measurement gas from the flue 1a, 1b, 1c, and a plurality of introduction pipes 4a, 4b, 4c for introducing the introduced sample gas. It comprises a pre-processing unit 200 that switches the gas line, and further switches between direct measurement and adsorption / desorption measurement, and an analyzer 300 that analyzes the switched gas.

  Sampling units 100a, 100b, and 100c are composed of sampling nozzles 2a, 2b, and 2c and dust filters 3a, 3b, and 3c. When measuring a relatively high mass organic compound, the sampling units 100a, 100b, and 100c are almost the same as the sample gas in order to prevent adsorption and chemical reaction. The same temperature is maintained at about 100 to 250 ° C.

  Since corrosive substances may also be included, SUS or glass having a corrosion resistance or a material equivalent to or higher is usually used. Similarly, the plurality of introduction pipes 4 are usually made of a corrosion-resistant material and are maintained at a temperature of about 100 to 250 ° C.

  The pretreatment unit 200 is provided with suction pumps 6a, 6b and 6c for sucking the sample gas of each line, flow meters 7a, 7b and 7c for measuring the flow rate thereof, and valves 10a, 10b and 10c for arbitrarily opening and closing each line. Further, a valve 15 for guiding the selected measurement gas line to the direct mechanism 25 and a valve 11 for switching to the adsorption / desorption mechanism 60 are provided.

  The valves 15 and 11 serve as switching means (switching mechanism).

  The adsorption / desorption mechanism 60 includes a valve 11 for guiding the sample gas introduced from the introduction pipes 4a, 4b, and 4c, a clean gas 30 such as dry air and nitrogen, a valve 12 for guiding the gas 30, and the introduced sample. An adsorption pipe 20 for adsorbing gas, a suction pump 50 for introducing the sample gas to the adsorption pipe 20, a flow meter 40 for measuring the amount of the sucked gas, a valve 13 for exhausting the gas at the time of adsorption, and a gas at the time of desorption Is constituted by a valve 14 for guiding the gas to the analyzer 300.

  The valves 11 and 12 serve as a switching mechanism between the sample gas line and the clean gas line. The valves 14 and 13 serve as a switching mechanism that switches between a line that exhausts the gas that has passed through the adsorption pipe and a line that leads to the analyzer.

  Since the adsorption tube 20 requires heat resistance and corrosion resistance, a container such as glass is used, and as the adsorbent 23, resin such as Tenax, polyurethane, XAD-2 or the like is used. A glass or metal filter 24 is provided at the inlet of the adsorption tube 20 to remove components other than gas.

  However, when the removal by the dust filters 3a, 3b, and 3c of the sampling units 100a, 100b, and 100c is sufficient, the filter 24 may not be provided. The adsorption tube 20 is provided with a cooler 22 for cooling the adsorption tube 20. When the sample gas is sucked by the pump 50, the sample gas is adsorbed and concentrated.

  The cooler 22 uses a cooler such as FAN or Peltier depending on the required cooling temperature. Further, the adsorption tube 20 is provided with a heater 21 for heating the adsorption tube 20 to about 300 to 400 ° C., and is desorbed by being sucked by the suction pump 330 of the analyzer 300 while being heated at the time of desorption after adsorption. The gas is measured by the analysis unit 310.

  Further, since the adsorption tube 20 is a consumable item, it needs to be replaced periodically. A pressure gauge 26 is provided to check for leaks after replacement, and a leak check due to pressure drop can be performed by containing gas with dry air 30 or the like.

  Furthermore, when the sample gas is a dangerous gas, if the adsorption tube is removed at random, gas leakage will occur, resulting in a safety problem. For this reason, it should also be considered to provide a cover (not shown) with a cover so that the adsorption tube cannot be replaced while the sequence is being executed. It is effective to automatically lock the key so that no person is involved.

  The analyzer 300 includes an analysis unit 310, a flow meter 320, and a suction pump 330. The analysis unit 310 includes a mass spectrometer that performs component analysis and quantification of the gas from the direct mechanism 25 and the gas concentrated in the adsorption tube 20, and particularly ionizes a gas called APCI (atmospheric pressure chemical ionization) method. A mass spectrometer that performs mass spectrometry is preferred.

  According to this, the gas desorbed from the direct mechanism and the adsorption tube can be measured instantaneously. Although not shown in the figure, sequence control of the preprocessing unit 200, control of the analyzer 300, and data processing are performed by a PLC, a PC, and a dedicated control board.

  The operation will be described below with reference to FIG.

  The sample gas in the flue is sucked through the sampling nozzles 2a, 2b and 2c by the suction pumps 6a (only 6a is shown, 6b and 6c are not shown). The sucked sample gas is guided to the pretreatment unit 200 through the introduction pipes 4a, 4b, and 4c after the dust is removed by the dust filters 3a, 3b, and 3c.

  The sample gas is kept at a temperature of about 100 to 250 ° C. by the heater (heater) 5c until it is led to the pretreatment unit 200, thereby suppressing the occurrence of adsorption as much as possible. The sample gas guided to the pretreatment unit 200 opens the valves 10a, 10b, and 10c (10a in the figure) of the line to be measured, and closes the valves 10a, 10b, and 10c (10b and 10c in the figure) of the other lines. Thus, only one line is selected and guided to the analyzer 300.

  If the sample gas is relatively clean and contains few contaminant components before being led to the analyzer 300, the valve 15 is opened and led to the analyzer 300 via the direct mechanism 25.

  If the sample gas contains a lot of contaminants, if it is led to the analyzer 300 as it is, the measurement sensitivity will drop or the measurement will become impossible. Therefore, the valve 11 is opened and led to the adsorption / desorption mechanism 60 to keep the gas clean. After that, it is led to the analyzer 300.

  If the gas component is known in advance as to whether to use the direct mechanism or the adsorption / desorption mechanism, it is set according to the line selected and set in advance in the control unit. If the gas component is not known, it can be switched to the adsorption / desorption mechanism 60 if it is actually measured and not direct.

  When the direct mechanism 25 is selected, the valve 15 is opened, the valve 11 is closed, and the sample gas is directly introduced to the analyzer 300 and analyzed by the analysis unit 310. When the adsorption / desorption mechanism 60 is selected, the valve 15 is closed and the valve 11 is opened, and the sample gas is guided to the adsorption tube 20 by the suction pump 50.

  The adsorption flow rate is integrated by the flow meter 40 and used for concentration conversion. In the adsorption tube 20, the gaseous organic matter is adsorbed by cooling to around 0 to 100 ° C. with the cooler 22, and the concentrated sample gas component accumulates in the adsorption tube 20 after a predetermined time has elapsed. Other inorganic substances pass through the adsorption pipe 20 and are discharged through the exhaust line 8.

  By changing the temperature of the cooler 22, unnecessary organic compounds can be passed in addition to inorganic substances. For example, if the temperature at the time of adsorption is increased, the low mass number organic compound has a low boiling point and is easily vaporized, so that it passes through the adsorption tube.

  If the cooling temperature is set near the upper temperature limit at which the object to be measured adsorbs or does not evaporate, the vaporized component below that temperature passes through the adsorption tube 20 and therefore removes as much extraneous components as possible. And the influence of contamination can be reduced.

  After adsorption, the valve 11 and the bubble 13 are closed, and the valve 12 and the valve 14 are opened to perform desorption. The adsorption tube 20 is gradually or rapidly raised to about 300 to 400 ° C. by the heater 21, and the organic substance concentrated in the adsorption tube 20 is desorbed gradually and at once by pushing in a clean gas gas 30 such as dry air or dry nitrogen. Then, it is guided to the analyzer 300.

  By measuring this with a gas chromatograph or mass spectrometer, the components can be analyzed. In particular, in the APCI method, gas can be instantaneously ionized and the signal can be captured by a mass spectrometer, so that the components in the adsorption tube can be measured in a few minutes.

  The analysis ends here, but normally, after the measurement, the excess components are removed by heating to clean the adsorption tube. When there are many high-mass impurities, it is possible to raise the heating temperature of the adsorption tube to make it clean.

  When there is almost no high-order impurities, the clean process may be omitted. Thus, a series of adsorption, desorption, and cleaning are performed, and a standby state is entered until the next adsorption starts.

  FIG. 6 shows a sequence during direct and adsorption / desorption mixing. When each sample gas line is measured in the order of 4a → 4b → 4c, and the 4a and 4b lines are direct and the 4c line is adsorbed / desorbed, the valve 10a of the 4a line and the valve 15 of the direct mechanism are first connected. Open at least the valves 10b, 10c, 11, and 14.

  Thereby, the gas of the 4a line is guided to the analysis unit 300 and measured. Next, when switching to the 4b line after a certain period of time, the valve 10a is similarly closed, and if the 10b is opened, the 4b line is measured.

Next, when switching to the 4c line, the valves 10a and 10b are closed and 10c is opened.
At the same time, the valve 15 of the direct mechanism is closed and the valves 11 and 13 of the adsorption / desorption mechanism are opened to introduce gas into the adsorption pipe for adsorption.

  After adsorption for a certain time, the valves 11 and 13 are closed for desorption, the valves 12 and 14 are opened, and the gas concentrated in the adsorption tube is guided to the analyzer 300 and measured. After the adsorbed target component is released, cleaning is performed in order to discharge the contaminant components remaining in the adsorption tube.

  Keep the valve on and off, and clean it by raising its temperature to or above that temperature. This completes the series of sequences. The same sequence is repeated thereafter. Also, depending on the situation, it is possible to change the order of the switching lines or skip the abnormal lines.

  It is also possible to increase the total number of lines or to change the number of direct and adsorbing / desorbing lines.

  As described above, according to the embodiment of the present invention, it is possible to continuously switch the exhaust gas and the air line at a plurality of locations, and to analyze the organic compound in the gas easily and quickly and efficiently while maintaining accuracy. .

  Moreover, direct and adsorption / desorption can be switched according to the properties of the measurement gas, and the measurement accuracy can be maintained.

  Another embodiment of the present invention is shown in FIGS.

  FIG. 3 shows a case where two sets of adsorption / desorption mechanisms are provided, and the configuration of each adsorption / desorption machine is the same as FIG. Although FIG. 2 illustrates the case where one sample line is used for adsorption / desorption, two sample lines can be adsorbed / desorbed by one adsorption / desorption mechanism.

  However, since the adsorption / desorption sequence takes more time than direct, it takes more time to adsorb / desorb two lines, and the time for switching all lines may be longer. Therefore, FIG. 3 shows an example in which a plurality of adsorption / desorption mechanisms are provided to simultaneously advance adsorption / desorption and shorten the switching time.

  That is, while one adsorbing / desorbing mechanism is desorbing, another adsorbing / desorbing mechanism performs adsorption to reduce time.

  In the example of FIG. 3, two adsorption / desorption mechanisms are provided in the direct mechanism, and the line is switched according to each sample gas. FIG. 7 shows a sequence when there are a plurality of direct and adsorption / desorption mechanisms.

  When each sample gas line is measured in the order of 4a → 4b → 4c, and the 4a line is direct and the 4b and 4c lines are adsorbed / desorbed, the valve 10a of the 4a line and the valve 15 of the direct mechanism are first set. Open at least the valves 10b, 10c, 11a, 11b, 14a and 14b.

  Thereby, the gas of the 4a line is guided to the analysis unit 300 and measured. Next, when switching to the 4b line after a certain time, the valves 10a and 10c are closed and 10b is opened. At the same time, the valve 15 of the direct mechanism is closed, the valves 11a and 13a of the upper adsorption / desorption mechanism are opened, and the gas is introduced into the adsorption pipe for adsorption.

  During this time, the valves 11b and 13b of the lower adsorption / desorption mechanism remain closed. When the adsorption of the 4b line is finished, the valves 11a and 13a are closed for desorption, the valves 12a and 14a are opened, and the gas concentrated in the adsorption tube is guided to the analysis unit 300 and measured.

  Here, when the adsorption of the 4b line is finished and the desorption is started, the measurement gas is switched to the 4C line, and the adsorption is performed by opening the valves 11b and 13b with the lower adsorption / desorption mechanism. During this time, the upper adsorption / desorption mechanism and the lower adsorption / desorption mechanism do not interfere with each other, and desorption can be performed at the upper stage and adsorption can be performed simultaneously at the lower stage.

  The upper adsorption / desorption mechanism may be cleaned when the lower adsorption / desorption mechanism performs adsorption. Desorption is performed by the upper adsorption / desorption mechanism, and when adsorption is completed by the lower adsorption / desorption mechanism, the valves 11b, 13b, 12a, and 14a are closed, the valves 12b and 14b are opened, and desorption is performed by the lower adsorption / desorption mechanism.

  This completes the series of sequences. When there are three or more lines where the measurement gas is to be adsorbed / desorbed, adsorption / desorption can be performed simultaneously by alternately using two adsorption / desorption mechanisms.

  Thus, according to another embodiment of the present invention, since adsorption and desorption can be performed simultaneously even when a plurality of adsorption and desorption is performed, there is an effect that the switching time can be shortened and quick measurement can be performed.

  FIG. 4 shows a case where the direct and the adsorption / desorption mechanism are determined in advance, and the configuration of the adsorption / desorption mechanism is the same as that of FIG. However, valves 11 and 15 for switching between direct and adsorption / desorption mechanisms are not provided. In this case, the operation is the same as in FIG. 2, and the valves 11 and 15 are omitted.

  As described above, according to the second embodiment of the present invention, if the line for performing adsorption / desorption is determined in advance, the direct line and the adsorption pipe line do not mix with each other. Can be eliminated, and the measurement can be performed with higher accuracy.

  Further, since the switching parts such as valves can be saved, there is an effect that the configuration and operation are simplified.

The block diagram of an on-line analyzer with a switching mechanism. BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of one Example of an on-line analyzer with a switching mechanism and adsorption / desorption mechanism based on this invention. The other Example with the switching mechanism based on this invention and several adsorption / desorption mechanism. The other Example with the switching mechanism and adsorption / desorption mechanism based on this invention. Direct measurement sequence with switching mechanism. The direct and adsorption / desorption mixed measurement sequence according to the present invention. 6 shows a direct and adsorption / desorption mixed measurement sequence according to another embodiment of the present invention.

Explanation of symbols

  1a, 1b, 1c ... flue, 2a, 2b, 2c ... sampling nozzle, 3a, 3b, 3c ... dust filter, 4a, 4b, 4c ... introduction piping, 5a, 5b, 5c ... heater (heater), 6a, 6b, 6c ... suction pump, 7a, 7b, 7c ... flow meter, 8 ... exhaust line, 10a, 10b, 10c ... valve, 11-15 ... valve, 20 ... adsorption pipe, 21 ... heater, 22 ... cooler, 23 ... Adsorbent, 24 ... Filter, 25 ... Direct mechanism, 26 ... Pressure gauge, 30 ... Air or nitrogen, 40 ... Flow meter, 50 ... Suction pump, 60 ... Adsorption / desorption mechanism, 100a, 100b, 100c ... Sampling unit, 200 ... Pretreatment unit, 300 ... Analyzer, 310 ... Analysis unit, 320 ... Flow meter, 330 ... Suction pump.

Claims (9)

Direct piping for directing the gas to be analyzed from the gas inlet to the analyzer;
An indirect pipe that leads to the analyzer through an adsorption / desorption device for concentrating and desorbing the gas to be analyzed,
And a switching means for switching between the direct piping and the indirect piping. In claim 1,
A gas analyzer comprising a plurality of indirect pipes. In claim 1 or 2,
A gas analyzer comprising a mechanism for switching the direct pipe and the indirect pipe according to the type of gas to be analyzed and operating a switching means so that the different types of gases are not mixed. In any one of Claims 1, 2, and 3,
The adsorption / desorption device switches an adsorption tube, a mechanism for heating and cooling the adsorption tube, a switching mechanism for switching between a sample gas line and a clean gas line, a line for exhausting gas passing through the adsorption tube, and a line leading to the analyzer. A gas analyzer comprising a switching mechanism. In claim 4,
The gas analyzer according to claim 1, wherein the temperature of the cooling mechanism of the adsorption pipe is set in the vicinity of an upper limit temperature at which the measurement target component is not adsorbed or vaporized. In claim 4,
A gas analyzer comprising a pressure gauge in the adsorption / desorption device, and means for containing gas before and after the adsorption tube to detect gas leakage in the vicinity of the adsorption tube due to pressure drop. In claim 4,
A gas analyzer characterized in that a key is attached to the attachment / detachment mechanism of the adsorption tube of the adsorption / desorption device so that the adsorption / desorption device is released under specific conditions. In any one of Claims 1, 2, and 3,
The gas analyzer is characterized in that a switching sequence of the switching means can be selected automatically or manually, and a plurality of sample gas lines are set so as to be arbitrarily assigned to a direct mechanism and an adsorption / desorption mechanism.   The gas analyzer according to any one of claims 1 to 8, wherein the gas analyzer is an online gas analyzer that transmits an analysis result via a communication line.

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