JPH11295292A - Chlorobenzenes analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for analyzing chlorobenzenes in exhaust gases without the need for a dehumidifier. SOLUTION: A device for automatically analyzing chlorobenzenes is provided with at least a concentrating device 2, a gas chromatograph 5, and a detector 6, and a data processing device 8 as necessary. The concentrating device 2 comprises a heating means 3 and a cooling means 81 using a low-temperature fluid, is capable of temperature control, and is placed in a low-humidity or low-moisture atmosphere. In addition, the device for automatically analyzing chlorobenzenes is provided with a gas straying means 63 to spray dry air or inert gas to the outside part of the concentrating device 2 and a piping system to introduce a gas containing helium as a main component, which is the carrier gas of the gas chromatograph 5, from the gas outlet of the detector 6 to the gas spraying means 63.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to, for example, combustion exhaust gas generated when incinerating general waste and industrial waste,
Alternatively, the present invention relates to an apparatus for automatically analyzing a chlorine-based organic compound contained in a gas or the like discharged from a metal refining process.

[0002]

2. Description of the Related Art Generally, when various kinds of waste are incinerated, extremely intoxicating dioxins are generated from incinerators. Since the concentration of dioxins contained in these exhaust gases is about 1 ng / Nm ³ (equivalent value of toxicity) or less even when dioxin and its homologues, and dibenzofuran and its homologues are all added, the current technology is It is not possible to measure directly.

The Journal of the Air Pollution Society, Vol. 28, No. 5, 27
Since chlorobenzenes have a high degree of correlation with dioxins as shown in FIG. 6 on page 4 (1993), it is necessary to measure chlorobenzenes and calculate the concentration of correlated dioxins. is there. Therefore, it is extremely important to accurately determine chlorobenzenes in exhaust gas.

A technique for automatically analyzing chlorobenzenes in exhaust gas is disclosed in the bulletin of the Institute for Environmental Studies, Yokohama National University, Vol.
992). That is, it is based on a glass trap for removing water vapor contained in exhaust gas, a concentration tube (adsorber) filled with a resin adsorbent, a heater capable of heating the same, and a gas chromatograph device. .

[0005] According to this, first, the exhaust gas is drawn by a pump downstream of the concentrating tube, the steam is removed by a glass trap, and then passes through the concentrating tube. At this time, since the condensing tube is not cooled or heated at a substantially normal temperature, the chlorobenzenes in the exhaust gas are adsorbed by the resin adsorbent. Next, the line is switched at the same time as the temperature of the concentrating tube is raised to 270 ° C., and the carrier gas of the gas chromatograph is passed through the concentrating tube and sent to the gas chromatograph. As a result, the adsorbed chlorobenzenes are desorbed and quantified by a gas chromatograph (the detection means is a flame ionization detector).

Incidentally, the concentration of chlorobenzenes in the exhaust gas at this time is 4 to 34 μm in monochlorobenzene.
g / Nm ³ , 4-65 μg with 1,4-dichlorobenzene
/ Nm ³ , ³ to 10 μg / N with hexachlorobenzene
m ³ , 27 to 186 μg with 2,4-dichlorophenol
/ Nm ³ , ² , ³ , ⁴ , 6-tetrachlorophenol is reported to be 4 to 45 μg / Nm ^3, and the concentration of exhaust gas is reported to be 3.2 liters.

Further, in the technique for automatically analyzing chlorobenzenes as a substitute index for dioxins described in Japanese Patent Application Laid-Open No. 5-313796, it is assumed that an electron capture detector for high sensitivity detection is used. However, cold trap injector as a technology to increase sensitivity,
Or, it does not employ other high sensitivity technology. Therefore, it is described that about 6 liters of exhaust gas is concentrated. Naturally, the amount of moisture in the exhaust gas is brought into the gas chromatograph apparatus, so that it is necessary to perform dehumidification as a pretreatment.

[0008]

In the above-mentioned prior art,
When removing water vapor (moisture) in waste gas from a refuse incinerator using a glass trap or an electronically cooled dehumidifier, chlorobenzenes, especially high-boiling chlorobenzenes or chlorophenols with a large number of chlorine additions, are converted into condensed water. It is captured. Furthermore, since the amount is affected by the moisture concentration (amount) in the exhaust gas, there is a problem that the measurement accuracy is reduced. In addition, since the dehumidifier is cooled, there is a problem that chlorobenzenes themselves condense and adhere to the inside of the dehumidifier.

In addition, the exhaust gas of a recent state-of-the-art waste incinerator (so-called dioxin countermeasure furnace) generally has a reduced content of chlorobenzenes, which is about 1/100 that of the conventional exhaust gas. For example, 0.5 μg / dichlorobenzene
It is about Nm ³ . For this reason, chlorobenzenes are taken into the moisture inside the dehumidifier, or condensed
When the adhesion occurs, there is a problem that the absolute amount of chlorobenzenes introduced into the gas chromatograph decreases and the detection becomes impossible.

At the current low emission level, it is necessary to concentrate at least about 10 liters of exhaust gas when using a gas chromatograph-mass spectrometer. Therefore, if the dehumidifier is simply removed, the separation column in the gas chromatograph device is caused by the action considered to be caused by the moisture contained in the waste gas from the incinerator and hydrogen chloride, chlorine, or sulfur oxide. Deteriorates or is damaged.
Exhaust gas contains mainly chlorobenzenes and chlorophenols, as well as nitrogen, oxygen, chlorine and hydrogen chloride, sulfur oxides, and various organic compounds. And cannot be quantified.

In some cases, a so-called liquid phase component containing polysiloxane as a main component attached to the inner surface of the separation column flows out and is detected.

These problems in the prior art can be solved as follows as a result of investigation. In the course of the study, we used an electron capture detector, which is a highly sensitive detector for chlorine in chlorobenzenes contained in waste gas from incinerators.
It has been found that the peak width of the gas chromatogram becomes narrower when the adsorption and concentration are performed by controlling the temperature of the resin adsorbent concentrator to a low temperature in order to further improve the sensitivity. As a result, the signal / noise ratio is improved, and even a complex mixture such as exhaust gas and containing a substance that degrades the separation column can be detected even if the amount of suction and concentration is small.

[0013] This is because, when the adsorption and concentration are performed at a low temperature, the adsorption efficiency is improved, and the adsorption can be performed in a small area (a minute portion of the resin adsorbent) when adsorbing to the concentrator. In addition, it is presumed that introduction can be performed with a narrow bandwidth. Therefore, since the absolute amount of water introduced into the gas chromatograph becomes small,
The need for a dehumidifier is eliminated.

Here, in order to lower the temperature of the concentrator (adsorption tube), it is effective to spray a low-temperature cooling gas, for example, liquefied carbon dioxide gas or liquid nitrogen gas, and to control the temperature by heating the heater. Usually, since the adsorption tube is compact and small, it reaches a predetermined temperature immediately, and the cooling gas is sprayed intermittently.

If the humidity of the atmosphere in which the concentrator is installed is high, such as on a rainy day, and when the blowing of the cooling gas is stopped, the space between the blowing nozzle and the case is closed. It was found that the water became ice and adhered and grew. This is almost no problem when the concentration time of the exhaust gas is as short as about 5 minutes. However, when the concentration time is long, it gradually grows and grows after icing, thereby impeding the flow of the cooling gas.

As a result, the cooling gas does not flow uniformly, causing a drift. Due to this drift, a part of the adsorption tube is supercooled, and inside the part, the water in the exhaust gas becomes ice and adheres. Therefore, even if a resin adsorbent which is relatively not adsorbed with water is used, the water is concentrated in the concentrator. When this moisture is introduced into the gas chromatograph, the separation column may be damaged as described above, or even if it does not reach the separation column, the baseline may fluctuate, which may affect the quantification.

The present invention has been made in order to solve such problems, and does not require a dehumidifier, and has no icing of water even when the concentrator is cooled. Another object is to provide an apparatus for analyzing chlorobenzenes in exhaust gas from a metal refining process or the like.

[0018]

As a result of intensive studies to solve the above-mentioned problems, it has been found that it is desirable to lower the humidity of the environment (atmosphere) in which the concentrator is installed.
The present invention has been completed.

The first invention is an automatic analyzer for chlorobenzenes provided with at least a concentrator, a gas chromatograph, a detector and, if necessary, a data processor. An apparatus for analyzing chlorobenzenes, comprising a cooling means used, temperature controllable, and installed in an atmosphere with low humidity or low moisture.

In the present invention, the above-mentioned problem is solved by installing the concentrator in an atmosphere having a low humidity. Further, the object of the present invention is achieved by applying the present invention to an automatic analyzer constituted by a concentrator, a gas chromatograph device, and preferably an electron capture detector as a detecting means.
Hereinafter, each component of the apparatus of the present invention will be described.

The concentrator for chlorobenzenes is made of a glass or metal tube (adsorption tube) filled with a resin adsorbent, heating means such as a heater capable of raising the temperature of the adsorption tube to about 300 ° C., and the above-mentioned dust remover. What is necessary is just to have a pump and a gas flow meter capable of sucking the exhaust gas, and a mechanism capable of sending an inert gas such as helium gas to the gas chromatograph device through the adsorption tube.

The concentrator also has a function of blowing a cooling gas such as liquefied carbon dioxide gas or liquid nitrogen gas onto the adsorption tube, and has a function of controlling the temperature to a low temperature during the operation of adsorbing components (chlorobenzenes) in the exhaust gas. It is necessary to have. At this time, in order to uniformly cool the suction tube having a certain length, it is preferable to store the suction tube in a case so that the low-temperature fluid can be distributed throughout.

According to a second aspect of the present invention, there is provided an apparatus for analyzing chlorobenzenes according to claim 1, wherein said concentrator is provided with gas blowing means for blowing dry air or inert gas to the outside thereof. is there.

In the present invention, a gas containing no moisture is blown into the case by blowing a gas containing no moisture to the concentrator, and a gas containing almost no moisture such as nitrogen, helium, or argon is blown into the case to purge the moisture. To reduce the humidity of the atmosphere of the nozzle portion of the low-temperature fluid (cooling gas) and the portion between the suction pipe and the case. In this way, ice is prevented from growing outside the concentrator when the cooling gas is stopped. There is no particular limitation on the gas to be injected as long as it is a gas that does not contain moisture.However, those containing flammable gas as the main component are in danger of ignition or explosion, and explosion-proof measures must be taken. Better. The same applies to harmful gases.

According to a third invention, a gas mainly containing helium, which is a carrier gas of a gas chromatograph, is used.
A chlorobenzenes analyzer according to the first and second aspects of the present invention, further comprising a piping system for guiding gas from the gas outlet of the detector to the gas blowing means.

According to the present invention, helium gas discharged through a detector such as an electron capture detector can be used as the gas to be blown to the concentrator, so that helium gas can be effectively used.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION In carrying out the present invention, first, if dust or mist is contained in exhaust gas, it will cause measurement hindrance or soil the measuring device. Remove dust and mist from supplied exhaust gas. Although a general dust filter may be used for this dust remover, it is necessary to control the temperature so that chlorobenzenes are not adsorbed. In other words, the whole is put in a constant temperature bath, or a heater is wound, for example, for 100 to 30 days.
0 ° C., preferably 120-160 ° C.

However, the dust remover may be omitted when the amount of dust and mist in the exhaust gas is very small, such as the piping downstream of the bag filter in the municipal solid waste incineration process, that is, when the exhaust gas is sufficiently clean.

Further, if an exhaust line is provided so that a dry purge operation for removing a trace amount of water adsorbed on the adsorbent can be performed, there is no problem even if a large amount of exhaust gas is sucked. Very preferred.

The gas chromatograph may be equipped with a normal capillary column and may have a function of raising the temperature to about 300 ° C. For the detector, it is necessary to use an electron-capture detector which is highly sensitive to chlorine constituting chlorobenzenes in order to improve the sensitivity. The adoption of an electron capture detector with high sensitivity to chlorine in chlorobenzenes allows the sensitivity to be improved by lowering the adsorption / concentration temperature, so that the exhaust gas concentration can be reduced to about 1/5 to 1/100. Becomes possible. Therefore, the amount of water brought into the gas chromatograph (separation column) is extremely small, and the separation column does not deteriorate even if the dehumidifier is omitted.

In addition, a data processing function that can receive the signal output from the detector and convert it into the amount of chlorobenzenes is required. Furthermore, from the main purpose of this automatic analysis, it is desirable that the correlation between chlorobenzenes and dioxins be determined in advance and converted into the amount of dioxins. The control of the entire exhaust gas analysis system at the time of exhaust gas analysis can be performed by a sequencer, but can be performed by the above-described data processing device.

[0032]

FIG. 1 is a block diagram showing an embodiment of an exhaust gas analyzer for automatically analyzing chlorobenzenes in exhaust gas. This device has a dust remover 1 with a built-in filter, a concentrator 2, a gas chromatograph device 5 (equipped with an electron capture detector 6), a sequencer 7 for controlling the entire analysis system, and chlorobenzenes calculated from the measured chromatogram. And a data processing device 8 for performing the processing.

The dust remover 1 was kept at 150 ° C. in a constant temperature bath using a fiber filter. The concentrator 2 can cool and heat the glass tube filled with the resin adsorbent, and can purge the glass tube with an inert gas (helium gas) containing no water. 3mm diameter, 1
A glass tube having a length of 00 mm and filled with a 2,6-diphenyl-p-phenylene oxide resin adsorbent was used. In addition, a heater 3 is wound around the adsorption tube,
Case 4 with 5mm diameter and 120mm length with both ends slightly squeezed
Put in. The case 4 is provided with a cooling means for spraying liquefied carbon dioxide gas from the carbon dioxide gas cylinder 80,
The temperature could be controlled to 00 ° C.

Also, a piping system capable of purging the inside of the adsorption tube of the concentrator 2 with the helium gas from the helium gas cylinder 60 was manufactured as a trial. The helium gas from the helium gas cylinder 60 is sent to the concentrator 2 via line 61 and
A dry purge operation of evacuating at 6 was enabled. In this way, when the line is switched to 35 and the temperature of the concentrator 2 is raised, the chlorobenzenes of the concentrator 2 are introduced into the gas chromatograph device 5.

The gas chromatograph 5 is HP5890
The type and detector used were an electron capture type manufactured by Barco, and the data processor used was a personal computer type. Also,
The column used was a micropolar column manufactured by GL Sciences Corporation.

The sequencer 7 is a prototype of a pump 10 for sucking exhaust gas through a concentrator (adsorption tube).
The diaphragm type pump was used, and the flow meter 12 for measuring the exhaust gas flow rate was an integrating type. Further, although not described in detail, valves were appropriately attached to the pipes connecting the devices (normal valves, three-way valves, and six-way valves) so that the following operations could be performed.

The automatic analysis was performed according to the following procedure (operation). The gas chromatograph device 5 supplies helium as a carrier gas from a helium cylinder 60 through a line 62 to be in a standby state. The exhaust gas 21 when the combustion load is 100% and the combustion state is extremely stable in the state-of-the-art refuse incinerator is supplied to the concentrator 2 by the line 31 and the line 33
, 1000 ml (milliliter) was sucked by the pump 10. At this time, the temperature of the concentrator 2 was kept at 0 ° C. Helium is sprayed on the concentrator 2 at all times.

Therefore, the helium cylinder 60 to line 6
Helium is sent to concentrator 2 through 1. The outlet side of the concentrator 2 was a line 36, and dry purging was performed for 2 minutes while the concentrator 2 was kept at 0 ° C.

When the line is switched to 35 and the temperature of the concentrator 2 is rapidly raised to 250 ° C. by the heater 3, the adsorbed chlorobenzenes are desorbed and enter the gas chromatograph through the line 35. At the same time line 62
Helium supply was stopped. The initial set temperature (temperature in the thermostat) of the gas chromatograph is set to room temperature and 10 ° C./mi.
The temperature was raised to 280 ° C. with n. As a result, the chlorobenzenes are sent to the gas chromatograph device 5, and the analysis values are automatically output from the data processing device 8.

FIG. 2 shows the obtained results. From the gas chromatogram in this figure, it can be seen that in the example, the shape of the peak corresponding to chlorobenzenes was good. Also, there is almost no change in the baseline. In addition,
This measurement was performed when the indoor humidity was 67%.

With respect to the comparative example, a test was performed by the same method using the same apparatus as that of the above example, except that the helium gas was not sprayed on the concentrator 2. The obtained gas chromatogram is shown in FIG. In this gas chromatogram, the baseline is considerably disturbed, and as a result, no chlorobenzene peak is found.

[0042]

According to the present invention, a technique for adsorbing and concentrating exhaust gas at a low temperature by a concentrator, which is a technique for increasing sensitivity, is adopted.
By reducing the humidity of the atmosphere around the concentrator, it becomes possible to omit a dehumidifier that has an adverse effect on the analysis value. In addition, this device has an effect that continuous measurement can be performed continuously for a long period of time without causing a change in the baseline, while omitting the dehumidifier.

[Brief description of the drawings]

FIG. 1 is a schematic view of an analyzer according to an embodiment of the present invention.

FIG. 2 is a gas chromatogram obtained in an example.

FIG. 3 is a gas chromatogram obtained in a comparative example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 dust remover 2 concentrator 3 heater 4 case 5 gas chromatograph device 6 electron capture type detector 7 sequencer 8 data processing device 10 pump 12 flow meter 21 gas (for analysis) 22 gas (exhaust) 31 to 36 Piping (for analytical gas) 60 Bomb (helium) 61-63 Piping (for helium) 80 Bomb (liquefied carbon dioxide) 81 Piping (for liquefied carbon dioxide) P1 Peak corresponding to chlorobenzene P2 Peak corresponding to dichlorobenzene P3 Trichlorobenzene Peak corresponding to P4 Peak corresponding to tetrachlorobenzene

Claims (3)

[Claims] 1. An automatic analyzer for chlorobenzenes comprising at least a concentrator, a gas chromatograph, a detector and, if necessary, a data processor, wherein the concentrator has a heating means and a cooling means using a low-temperature fluid. An apparatus for analyzing chlorobenzenes, wherein the apparatus has a temperature controllable and is installed in an atmosphere with low humidity or low moisture. 2. An apparatus for analyzing chlorobenzenes according to claim 1, wherein said concentrator is provided with gas blowing means for blowing dry air or inert gas to the outside thereof. 3. The gas chromatograph apparatus according to claim 1, further comprising a piping system for guiding a gas containing helium as a main component, which is a carrier gas of the gas chromatograph device, to gas blowing means from a gas outlet of the detector. An analyzer for chlorobenzenes according to claim 2.