JP2001289833A - Method for simply measuring dioxins or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for simply measuring dioxins or the like for safely and rapidly inferring the presence or absence and a concentration of the dioxins or the like in a burned exhaust gas by using its precursor. SOLUTION: The method for simply measuring the dioxins or the like comprises the steps of measuring a chlorobenzene or the like of the precursor of the dioxins or the like in the burned exhaust gas, and thereby inferring an amount of the dioxins or the like. The method further comprises the steps of collecting the chlorobenzene or the like in the exhaust gas by a previously cleaned adsorbing unit filling with an adsorber made of a polymer resin, measuring a content of the chlorobenzene or the like and inferring the content of the dioxins or the like in the exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel method for safely and quickly estimating and predicting the presence or absence or concentration of dioxins in flue gas by utilizing a substance highly correlated with dioxins in flue gas. The present invention relates to a simple and useful method for measuring dioxins.

[0002]

2. Description of the Related Art Tetrachlorodibenzoparadioxin (herein referred to as dioxins) is known as a toxic substance. Dioxin (2,3,7,8-tetrachlorodibenzoparadioxin), one of its isomers, is particularly highly toxic, very stable and poorly soluble in water, and its toxicity is not permanently eliminated. In Japan, since this substance has been detected and found in garbage incineration plants, great interest has been paid to it. There is a strong demand for the development of a simple, safe, fast, and accurate measurement method for its measurement and detection. I have.

Conventionally, measurement of dioxins has been carried out in accordance with the Ministry of Health and Welfare's Manual for Standard Measurement and Analysis of Dioxins in Waste Disposal (February 1997).
This measurement is a method of directly measuring dioxins using an apparatus as shown in FIG. 1, but the measurement takes a great deal of cost and time. For example, the measurement time is determined by collecting exhaust gas. It takes at least two weeks for the results to be available.

Further, carbon monoxide (CO) is measured in order to know the combustion state of the refuse and the like in the incinerator.
O is often used as an indicator of dioxins. However, as the management of the combustion state in a furnace such as a garbage incinerator progresses, and high accuracy is required for the management, CO is reduced to 10%.
In many cases, the concentration is less than ppm, but when CO is at such a low concentration, there are cases in which a correlation with dioxins cannot be obtained.

[0005]

SUMMARY OF THE INVENTION In view of the above problems in the conventional method for measuring dioxins, the present inventors have conducted various experiments on substances that are effective as alternative indices for CO, and pursued the present invention. As a precursor of dioxins present in various types of incinerators, we identified substances with the highest correlation with dioxins. Also,
In pursuit of a related measuring method, it was found that, for example, by improving the method of cleaning the adsorbent, the measuring time could be significantly reduced.

According to the present invention, based on these facts, the concentration of dioxins in flue gas is estimated and predicted by measuring the precursor of dioxins in flue gas, so that dioxins can be reduced in concentration. Even simple,
An object of the present invention is to provide a new and useful simple method for measuring dioxins that can be safely and quickly predicted.

[0007]

SUMMARY OF THE INVENTION The present invention provides a simple method for measuring dioxins by estimating the amount of dioxins by measuring chlorobenzenes, which are precursors of dioxins in the flue gas. It is characterized in that dioxins in combustion exhaust gas are estimated by collecting chlorobenzenes in the adsorption section filled with an adsorbent made of polymer resin washed in advance and measuring the chlorobenzenes content To provide a simple method for measuring dioxins.

Further, the present invention is a simple method for measuring dioxins in flue gas by measuring chlorophenols and chlorobenzenes which are precursors of dioxins in the flue gas to estimate the amount of dioxins. The chlorophenols in the combustion exhaust gas are collected at the drain portion, and the chlorophenols contained in the drain are extracted and concentrated. Estimate the dioxin content in the combustion exhaust gas by extracting and concentrating the chlorobenzenes adsorbed on the adsorbent, collected at the filled adsorption section, and measuring the contents of the chlorophenols and chlorobenzenes. A simple method for measuring dioxins is provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Dioxins are generated in incinerators for municipal waste and industrial waste, paper and pulp mills, and the like. FIG.
As described above, dioxins are generated through various routes in these incinerators, and one of them is a route in which chlorinated aromatic compounds are generated as precursors. According to the present invention, it has been found that the concentration of dioxins contained in the combustion exhaust gas generated in an incinerator for municipal waste and the like has a strong correlation between the concentrations of chlorobenzenes and chlorophenols.

Dioxins have a good correlation with chlorobenzenes, and also have a good correlation with chlorophenols, especially with trichlorophenol. The present invention takes advantage of this fact. That is, the present invention is based on the correlation, the content of chlorobenzenes in the combustion exhaust gas, or the presence or absence of dioxins in the combustion exhaust gas based on the content of chlorobenzenes and chlorophenols, or the content thereof This is a simple measurement method for estimating.

Further, according to the present invention, the amount of chlorobenzenes and chlorophenols contained in the combustion exhaust gas from incinerators such as municipal waste is two to four orders of magnitude larger than the amount of dioxins. I understood that. In the conventional method (manual), dioxins are measured directly. However, since dioxins in combustion exhaust gas are small in quantity, after extraction and concentration, removal of interfering components is performed to increase measurement accuracy. There is a need. On the other hand, since the amount of chlorobenzenes and chlorophenols in the combustion exhaust gas is large in quantity, in the present invention, the measurement can be performed only by extracting and concentrating them without removing the interfering components. . For the same reason, a general-purpose mass spectrometer (quadrupole type) can be used for the measurement instead of a high-sensitivity mass spectrometer (double focusing type), which is also advantageous in this respect.
Further, the amount of the collected sample gas may be smaller than that in the case where dioxins are directly measured.

Further, chlorobenzenes and chlorophenols have a lower boiling point than dioxins, and exist substantially in a gaseous state in combustion exhaust gas, so that the trapping device can be simplified. Further, since chlorobenzenes and chlorophenols are easily dissolved in a solvent, pretreatment of a collected sample is much easier than dioxins. For this reason, the collection and sample preparation time can be shortened, for example, to one tenth or less of dioxins, so that the measurement can be sped up. In addition, chlorobenzenes and chlorophenols are much less toxic than dioxins, and are safe and easy to handle for analysts.

FIG. 3 is a view showing an embodiment of a measuring apparatus preferably used for measuring chlorobenzenes and chlorobenzenes and chlorophenols in the present invention. As shown in FIG. 3, it comprises a glass tube for sampling flue gas from a flue or the like, an adsorption tube, a pump, a meter, and an oxygen concentration meter. In operation, exhaust gas is collected from a flue or the like by a sampling glass tube, and this sampling is performed by suctioning with a pump. The collected flue gas is passed through a drain or impinger,
Subsequently, it is passed through an adsorption tube filled with an adsorbent made of a polymer resin. Chlorophenols are mainly collected in the drain portion, and chlorobenzenes are mainly adsorbed to the adsorbent, so that they are extracted. Next, the extract is concentrated, and the concentration of chlorobenzenes and the concentrations of chlorobenzenes and chlorophenols are measured in the concentrated liquid. FIG.
An example of the measurement is shown as “Simplified method measurement flow”. For the concentration measurement, a GC / MS meter (SIM method) or the like is used.

In the present invention, for example, a flow rate of 3 L / min
(3 liters / min), when collecting garbage incinerator exhaust gas, chlorophenols are mainly collected in the drain,
It was found that chlorobenzenes were mainly collected by the adsorbent. For this reason, among these, when only (1) chlorobenzenes are measured, it is sufficient to measure only the adsorbent portion, and (2) when measuring chlorophenols and chlorobenzenes, respectively, the drain portion and the adsorbent portion are measured. The part may be measured.

In the above-described apparatus, a significant amount of chlorobenzenes is collected in the drain portion and a significant amount of chlorophenols is also collected in the adsorbent portion depending on conditions such as the flow rate of the exhaust gas. It may be trapped. In such a case, when measuring (2) chlorophenols and chlorobenzenes, the chlorobenzenes may be measured not only in the adsorbent section but also in the drain section. The section may also be measured.

Except in the above case, the measurement of trichlorophenols can be performed only by collecting the drain, so that the collecting device can be simplified. Extraction of trichlorophenols from the drain can be performed by a solid phase extraction method or a liquid-liquid shaking extraction method. As a solvent, a solvent having a high solubility of chlorophenols and a boiling point difference as large as possible from chlorophenols is used, and a preferable example thereof is dichloromethane. Next, after adding an internal standard substance to the extract, the extract is concentrated, and the concentration of the chlorophenols in the concentrate is measured.

As the adsorbent in the present invention, an adsorbent made of a polymer resin is used. Styrene divinylbenzene copolymer is a preferred example. However, polymer resin adsorbents such as styrene-divinylbenzene copolymers contain organic substances derived from the manufacturing process, etc., so it is necessary to desorb the organic substances before filling them as adsorbents. is there. In the present invention, when extracting an organic substance with a solvent, the organic substance in the polymer resin adsorbent can be effectively and rapidly removed by applying an ultrasonic cleaning method. As the solvent, a solvent having high solubility of organic substances and having a boiling point difference as large as possible is used, and a preferable example thereof is dichloromethane.

Further, since chlorobenzenes are mainly collected by the adsorbent, it is necessary to extract and concentrate the adsorbed chlorobenzenes after collecting the chlorobenzenes with the adsorbent made of a polymer resin. In the present invention, after the adsorption of the chlorobenzenes, the extraction of the chlorobenzenes from the adsorbent is also carried out by applying an ultrasonic cleaning method to the chlorobenzenes in the polymer resin adsorbent, by extracting the chlorobenzenes from the adsorbent with an effective and effective method. It can be removed quickly. As the solvent, a solvent having a high solubility of chlorobenzenes and a boiling point difference as large as possible is used, and a preferable example thereof is dichloromethane.

[0019]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, that is, Experimental Examples, but it goes without saying that the present invention is not limited to these Examples.

<1. Correlation test between dioxins and their precursors> FIGS. 4 and 5 show actual measurements of combustion exhaust gas discharged from an incinerator for municipal garbage. It is a test result about the correlation with chlorophenols. The measurement of dioxins was carried out in accordance with the “Manual for Standard Measurement and Analysis of Dioxins in Waste Disposal” by the Ministry of Health and Welfare (see FIG. 1). The measurement of chlorobenzenes and chlorophenols was performed on the same flue gas using the apparatus shown in FIG. The adsorption tube was filled with Amberlite XAD-2 (= trade name, styrene divinylbenzene copolymer) as an adsorbent. This adsorbent was previously washed by the method described in <3, Cleaning test of polymer resin adsorbent>.

As shown in FIGS. 4 and 5, chlorobenzenes and dioxins, and chlorophenols and dioxins in the combustion exhaust gas show a certain correlation.
First, as shown in FIG. 4, in the case of chlorobenzenes, it can be seen that the chlorobenzenes also increase or decrease in response to the increase or decrease in the dioxin concentration. For example, dioxin concentration 0.4 ng
In / Nm ^3, MCB is 130ng / Nm ³ about, TriC
Bs is about 450 ng / Nm ³ , TetraCBs is 50
It is about 0 ng / Nm ³ , and thereafter, these components also increase as the dioxin concentration increases.

Next, as shown in FIG. 5, in the case of chlorophenols, it can be seen that the chlorophenols also increase or decrease in accordance with the increase or decrease of the dioxin concentration. For example, at a dioxin concentration of 0.4 ng / Nm ³ , MCPs are 100 ng.
/ Nm ³ , DCPs about 250 ng / Nm ³ , TCP
s is about 1760 ng / Nm ³ , and thereafter, these components also increase as the dioxin concentration increases. In addition, it can be seen that among these components, the correlation with TCPs is particularly good.

In the present invention, these facts are utilized. That is, the concentration of chlorobenzenes or the concentration of chlorobenzenes and chlorophenols in flue gas from various incinerators and the like was measured, and the results were measured in advance for flue gas from various incinerators and the like. By estimating and predicting the concentration of dioxins in the exhaust gas by comparing with such a correlation. For chlorobenzenes, for example, if TetraCBs is about 500 ng / Nm ^3, shows that dioxin concentration is about 0.4 ng / Nm ^3, the case of chlorophenols, for example if TCPs is about 1760ng / Nm ³ It can be seen that the dioxin concentration is about 0.4 ng / Nm ³ .

Further, as is apparent from comparison of FIG. 4 and FIG. 5, in the case of chlorobenzenes and the case of chlorophenols, a similar correlation is shown with respect to the concentration of dioxins. It can be seen that the correlation with chlorophenols is good and their content is high. From this fact, it can be said that it is more effective to use chlorophenols as an index, but in the present invention, by measuring the concentration of chlorobenzenes and the concentration of chlorophenols from the same flue gas, it is possible to more accurately determine the concentration of dioxins. The concentration can be estimated.

<2. Collection test of dioxin precursor>
In this trapping test, the apparatus shown in FIG. 3 was used. The exhaust gas from the refuse incinerator flue is sampled by suction with a pump, passed through a drain section through an adsorption pipe, and the chlorophenols and chlorobenzenes absorbed and adsorbed by the drain section and the adsorption pipe are measured by a GC / MS-SIM meter. Quantified. The adsorption tube was filled with Amberlite XAD-2 (= trade name, styrene-divinylbenzene copolymer) that had been washed in advance by the method described in <3, Cleaning test of polymer resin adsorbent>. This resin is an adsorbent generally used for collecting dioxins in exhaust gas, but is also effective for collecting chlorobenzenes.

Table 1 shows the measured values. Table 1
In the above, CBs is an abbreviation for chlorobenzenes and CPs is an abbreviation for chlorophenols, and the meanings of the other symbols are described at the bottom of Table 1. As shown in Table 1, it can be seen that chlorophenols are mainly collected by the drain and chlorobenzenes are mainly collected by the adsorbent. For chlorophenols, for example, 4-MC
P, 2,4-DCP and 2,6-DCP have all or almost all of them contained in the drain, and 2,4,6-TCP
In this case, about 90% is collected by the drain. For chlorobenzenes, for example, MCB, DCBs,
TriCBs are all or almost all collected by the adsorbent, and 9 for 1,2,3,5-TCB.
About 0% or more and about 70% or more of 1,2,3,4-TCB are collected by the adsorbent.

[0027]

[Table 1]

<3. Washing test of polymer resin adsorbent> Since polymer resin such as styrene-divinylbenzene copolymer contains an organic substance due to its production process and the like, it is filled as an adsorbent. It is necessary to desorb organic matter beforehand. According to the “Manual for Standard Measurement and Analysis of Dioxins in Waste Disposal” (conventional method), before use for sample collection, Soxhlet extraction with toluene is carried out for 16 hours or more, and elution is carried out with toluene for washing.
Ultrasonic extraction with a 0 ° C. warm bath is shown to be performed three times for 30 minutes. However, this method requires such a long time for the pretreatment. In addition, since the boiling point of monochlorobenzene is 130 ° C. and the boiling point of toluene is 110 ° C., during the concentration operation after elution, the monochlorobenzene is volatilized along with the volatilization of the toluene. Cannot be extracted. Therefore, in the present invention, the extraction of organic matter from the adsorbent quickly and effectively,
Various experiments and examinations were conducted on the method of performing cleaning. The following is an example.

Dichloromethane having a high solubility for chlorobenzenes and chlorophenols and having a boiling point difference from monochlorobenzene was used as an extraction solvent. 50 g of Amberlite XAD-2 (trade name, styrene-divinylbenzene copolymer) as described above was mixed with dichloromethane (boiling point 40 ° C.) 2
Ultrasonic cleaning was performed at 00 ml for 15 minutes, and the extract obtained by changing the number of times of washing was concentrated to 1 ml by evaporation. The concentrated solution is subjected to gas chromatography-mass spectrometry (GC-M
S analysis) to determine the peak areas of chlorobenzenes and chlorophenols. FIG. 6 shows the result. As shown in FIG. 6, chlorobenzenes and chlorophenols can be almost completely removed by washing three times or more by the ultrasonic cleaning method.

Therefore, the above-mentioned dichloromethane was used for 15 minutes.
The Soxhlet extraction with toluene was carried out 16 times using the ultrasonic cleaning method three times (ultrasonic cleaning method) and the conventional method "Manual for standard measurement and analysis of dioxins in waste treatment."
A comparison experiment was performed with the case where the time was performed (Soxhlet extraction method). For each concentrate, GC-M
S analysis was performed to determine the peak areas of chlorobenzenes and chlorophenols. Table 2 shows the results.

[0031]

[Table 2]

As shown in Table 2, the peak areas of chlorobenzenes and chlorophenols by the ultrasonic cleaning method were as follows:
Excluding 1,2,3,5-TCB (TCB = trichlorobenzene) and PCB, all values are smaller than those of the Soxhlet method. From this, the ultrasonic cleaning method,
It is clear that chlorobenzenes (CBs) and chlorophenols (CPs) have the same washing and extraction ability as the Soxhlet extraction method.

As described above, chlorobenzenes are mainly collected by the adsorbent. Therefore, when chlorobenzenes are used as the indicator substance, the chlorobenzenes are collected by an adsorbent made of a polymer resin and then adsorbed. Although it is necessary to extract and concentrate the species, the above fact indicates that the ultrasonic cleaning method can be effectively applied also for the extraction. As described above, the ultrasonic cleaning method is equivalent in accuracy to the Soxhlet extraction method. In addition to the pretreatment of the adsorbent, extraction of chlorobenzenes after adsorption of chlorobenzenes and removal of chlorophenols from the drain are also performed. Since the present invention can be applied to extraction, the collection time and the measurement time can be shortened, which can greatly contribute to speeding up the measurement of chlorobenzenes and chlorophenols.

[0034]

According to the present invention, the concentration of dioxins in flue gas is used as an index of chlorobenzenes,
Alternatively, by using chlorobenzenes and chlorophenols, simple, safe and quick prediction can be made even at low concentrations of dioxins.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conventional dioxin measurement device.

FIG. 2 is a diagram showing a generation path of dioxins in an incinerator.

FIG. 3 is a diagram showing an example of an embodiment of a measuring device used in the present invention.

FIG. 4 is a diagram showing a correlation between dioxins in combustion exhaust gas and chlorobenzenes as precursors thereof.

FIG. 5 is a diagram showing the correlation between dioxins in combustion exhaust gas and chlorophenols that are precursors thereof.

FIG. 6 is a view showing a cleaning result of a polymer resin adsorbent by an ultrasonic cleaning method.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01N 33/00 G01N 33/00 C // B01J 20/26 B01J 20/26 A F-term (Reference) 4D056 AB18 AB20 AC04 BA08 CA23 CA39 4G066 AC12A AC12B CA33 DA02 EA20

Claims (11)

[Claims] 1. A simple method for measuring dioxins in which the amount of dioxins is estimated by measuring chlorobenzenes, which are precursors of dioxins in flue gas, wherein the chlorobenzenes in the flue gas are washed beforehand. A simple method for measuring dioxins characterized by estimating the content of dioxins in combustion exhaust gas by sampling at the adsorption section filled with an adsorbent made of a polymer resin and measuring the content of chlorobenzenes . 2. The simple method for measuring dioxins according to claim 1, wherein the adsorbent comprising the polymer resin is an adsorbent comprising a styrene-divinylbenzene copolymer. 3. The adsorbent according to claim 1, wherein the pre-washed polymer resin adsorbent is a polymer resin washed by an ultrasonic cleaning method using a solvent. A simple method for measuring dioxins. 4. The simple method for measuring dioxins according to claim 1, wherein the extraction of the chlorobenzenes adsorbed on the adsorbent is performed by an ultrasonic cleaning method using a solvent. . 5. The simple method for measuring dioxins according to claim 3, wherein the solvent is dichloromethane. 6. A simple method for measuring dioxins in flue gas, wherein the amount of dioxins is estimated by measuring chlorophenols and chlorobenzenes which are precursors of dioxins in the flue gas. The chlorophenols in the drain are collected at the drain to extract and concentrate the chlorophenols contained in the drain, and the chlorophenols in the combustion exhaust gas are filled with an adsorbent made of a polymer resin that has been washed in advance. Extracting the chlorobenzenes adsorbed on the adsorbent by sampling at
A simple method for measuring dioxins, comprising estimating the content of dioxins in combustion exhaust gas by concentrating and measuring the contents of chlorophenols and chlorobenzenes. 7. The simple method for measuring dioxins according to claim 6, wherein the chlorophenol is trichlorophenol. 8. The simple measurement of dioxins according to claim 6, wherein the extraction of chlorophenols contained in the drain is performed by a solid phase extraction method or a liquid-liquid shaking extraction method. Method. 9. An adsorbent made of a polymer resin washed by an ultrasonic washing method using a solvent, wherein the adsorbent made of a polymer resin washed in advance is an adsorbent made of a polymer resin washed by an ultrasonic washing method using a solvent.
A simple method for measuring dioxins according to any one of the above. 10. The simple method for measuring dioxins according to claim 6, wherein the chlorobenzenes adsorbed on the adsorbent are extracted by an ultrasonic cleaning method using a solvent. . 11. The simple method for measuring dioxins according to claim 9, wherein the solvent is dichloromethane.