JP2004286698A - Dioxin secondary-production capacity measuring apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for measuring production amount of secondarily produced dioxins in refuse incineration facilities and the like. <P>SOLUTION: A dioxin secondary-production capacity measuring apparatus comprises a sampling probe from sampling exhaust gas containing soot from a flue of an incinerator or the like, an exhaust gas cooling means for cooling the sampled exhaust gas, a soot-capturing filter for collecting the soot in the cooled exhaust gas, a capturing filter heater for executing secondary production reaction of a dioxin precursor or dioxins with the soot collected by the filter, a concentration pipe for adsorbing and collecting the produced dioxin precursor or dioxins from the filter in which a secondary production reaction is completed, a concentration pipe heater for heating-and-desorbing the concentrated dioxin precursor or dioxins by heating the pipe and an analyzing device for analyzing the dioxin precursor or dioxins heated-and-desorbed as described above. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４１】
【表２】

【００４２】
実施例２
実施例１における測定結果を踏まえて、ごみ焼却施設の二次生成抑制運転を実施した。二次生成によるダイオキシン前駆体測定値から、測定値の高い場合（１回目）終了時に、減温塔出口の温度を通常より２０℃下げて運転すると同時に、活性炭吹込量を通常吹込量の２倍に増加させて運転した。その結果、測定値は低減し（２回目）、二次生成反応によるダイオキシン前駆体発生量を低減することができた。
【００４３】
【発明の効果】
以上に示したように、本発明によれば、焼却炉等の煙道から煤塵を含む排ガスを採取する工程と、排ガスを冷却する工程と、該排ガス中の煤塵を捕集する工程と、捕集した煤塵を加熱してダイオキシン類およびダイオキシン前駆体の二次生成反応を行う工程と、二次生成反応により発生したダイオキシン類およびダイオキシン前駆体を分析する工程からなるダイオキシン類二次生成能の測定を行うことが可能であり、排ガス成分だけでなく排ガス処理過程における二次生成反応によるダイオキシン類発生量も測定することが可能となり、適切な二次生成の抑制運転ができるようになり、ダイオキシン類の排出量が常に低減される。
【図面の簡単な説明】
【図１】本発明の一実施例であるダイオキシン類二次生成能測定装置の概略構成を示す図である。
【符号の説明】
１…焼却炉煙道
２…サンプリングプローブ
３…排ガス冷却器
４…逆洗切替バルブ
５…煤塵捕捉フィルタ
６…捕捉フィルタ加熱器
７…逆洗用ポンプ
８…逆洗ライン切替バルブ
９…逆洗ライン
１０…濃縮管
１１…加熱脱着用加熱器
１２…ライン切替バルブ
１３…分析ライン
１４…加熱脱着用ポンプ
１５…サンプリング用吸引ポンプ
１６…ガスクロマトグラフ装置
１７…検出器（ＥＣＤ）
１８…加熱脱着ライン切替バルブ
１９…排気ライン
２０…サンプリング用吸引ポンプ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is, for example, incinerators for general waste, industrial waste and the like, various incinerators such as sludge incinerators, pyrolysis furnaces, measuring devices for the secondary generation ability of dioxins having dust discharged from melting furnaces and the like, and Related to the measurement method.
[0002]
[Prior art]
Generation and emission of toxic trace organic compounds including dioxins, which are extremely toxic, have been confirmed in incinerators for general garbage and industrial wastes, and reductions are required. At present, in combustion furnaces such as refuse incinerators, by controlling combustion temperature and air volume optimally, harmful substances such as dioxins generated during combustion are reduced as much as possible, and in the process of exhaust gas treatment, Dioxins in exhaust gas have been considerably reduced by spraying activated carbon and reducing the temperature of the dust collector. Dioxins emitted into exhaust gas are measured and evaluated by official analysis (JIS K 0311).
[0003]
[Problems to be solved by the invention]
In the current combustion control of refuse incinerators, the purpose is to perform so-called complete combustion, and control is performed so that the concentration of carbon monoxide (CO), which is an index of incomplete combustion, is not generated. However, in recent years, in refuse incinerators and the like in which combustion is strictly controlled, there is often no correlation between the CO concentration and the dioxin concentration. Regarding the correlation between the concentration of dioxins at the furnace outlet and the CO concentration, there is a report that the correlation between the low concentration of dioxins and the CO concentration is low (see Non-Patent Document 1).
[0004]
The generation of dioxins in combustion incinerators such as refuse incinerators is due to secondary generation in addition to combustion origin.Unburned carbon is mainly used as a raw material. There is also a report that dioxins are generated by the conversion reaction (see Non-Patent Document 2).
[0005]
Such unburned carbon is considered to adhere to a locally low temperature place due to temperature fluctuations of the entire incinerator such as deterioration of combustion and shutdown of the incinerator, and after adhesion, it becomes a catalyst for the secondary generation reaction of dioxins. By contact with dusts such as incineration fly ash, secondary generation of dioxins tends to occur. Thus, in recent waste incineration facilities, the correlation between the dioxin concentration and the CO concentration is weak, and the generation of dioxins is more dioxin due to secondary production than that from combustion that can be relatively judged from the CO concentration. It is estimated that the generated amount is larger.
[0006]
In order to reduce dioxins generated in incinerators, it is necessary to reduce CO concentration through thorough combustion management and reduce the amount of dioxins generated by secondary generation. However, at present, although the generation of dioxins is discussed, the amount of dioxins generated due to secondary generation cannot be predicted, so it may not be possible to appropriately suppress secondary production. In some cases, the emission of dioxins increased.
[0007]
[Non-patent document 1]
ISERGE Independent Research Report of the Institute of Global Environmental Engineering, 56 pages (1997)
[Non-patent document 2]
Proceedings of the 13th Japan Society for Waste Management Research Conference, 733-735 (2002)
[0008]
[Means for Solving the Problems]
The above problem is solved by the following invention.
A sampling probe for collecting exhaust gas containing dust from a flue such as an incinerator, an exhaust gas cooling means for cooling the collected gas, and a dust trapping filter for collecting dust in the cooled exhaust gas, A capture filter heater for performing a secondary generation reaction of dioxins or dioxin precursors by dust collected by the capture filter, and adsorbs dioxins or dioxin precursors generated from the capture filter after the secondary generation reaction A concentrating tube for recovery, a condensing tube heater for heating and desorbing the concentrated dioxins or dioxin precursor by heating the condensing tube, and an analysis for analyzing the thermally desorbed dioxins or dioxin precursor A dioxin secondary production ability measuring apparatus, characterized by comprising an apparatus,
A step of collecting exhaust gas containing dust from a flue such as an incinerator, a step of cooling the collected exhaust gas, a step of collecting dust in the exhaust gas, and heating the collected dust to obtain dioxins and A method for measuring the secondary production of dioxins, comprising a step of performing a secondary production reaction of a dioxin precursor, and a step of analyzing dioxins and the dioxin precursor generated by the secondary production reaction.
[0009]
In the present invention, in the closed type, the amount of dioxins generated by contacting the unburned carbon and the like attached to the dust with the catalyst component in the dust in the secondary generation is obtained, and in the exhaust gas flow type, The amount of dioxins generated by contact of components such as unburned carbon in exhaust gas with catalyst components in dust is obtained.
[0010]
When these data are obtained, it is possible to grasp the amount of dust adhering to the flue of incinerators and the like, and to estimate the amount of unburned carbon and other components in exhaust gas. ) Can be used as an index to know the status of cleaning, and when starting up an incinerator, etc., it can be used to check the cleaning status. If the amount of dust attached is large, it is possible to take measures such as setting the temperature of the incinerator flue to be high or cleaning the flue by blowing air.
[0011]
Dioxins are a general term for polychloro-dibenzo-p-dioxins, polychloro-dibenzofurans, and coplanar PCBs.
[0012]
The dioxin precursor is a substance immediately before the generation of dioxins, and the main precursors include chlorobenzenes and chlorophenols. In addition, organic chlorine compounds such as chloronaphthalenes and chlorotoluenes may be mentioned as dioxin precursors.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Typical incineration facilities include an incinerator, a boiler, a cooling tower, a dust collector, and a chimney in this order.
[0014]
In the present invention, first, exhaust gas containing dust is collected from a flue such as an incinerator. However, in consideration of a temperature range of secondary generation of dioxins, it is preferable to collect the exhaust gas in a range from a boiler flue to an outlet of a cooling tower. The method of collecting the exhaust gas is not particularly limited, but it is preferable to connect the sampling part to the flue in the case of performing the measurement constantly. This sampling unit may be simply connected to a tube, but it is preferable to use a sampling probe.
[0015]
The sampling probe may be any probe that can extract the exhaust gas from the flue without deteriorating its properties, and may be, for example, a probe simply inserted into the flue. There is no limitation on the direction of the port, but it is preferable to direct the pipe toward the flow of exhaust gas. However, usually, sampling is performed using a sampling probe for dioxins collection specified by the official analysis method (JIS K 0311).
[0016]
An exhaust gas cooling means is provided to cool the collected exhaust gas. This is because it is necessary to sufficiently cool the exhaust gas containing the dust so that the unburned carbon component and the organic compound that adhere to or pass through the exhaust gas and the dust do not cause a secondary generation reaction. The cooling means is preferably of a type that cools with a refrigerant through a partition wall such as a pipe so as not to affect the properties of the exhaust gas. As the refrigerant, cooling water may be used, or ethanol or the like may be used.
[0017]
The dust trapping filter has an average pore diameter of about 1 to 20 μm, preferably about 1 to 5 μm. This dust trapping filter must be made of a material that can withstand the collected dust when it is heated to 300 to 500 ° C. to cause a secondary generation reaction, and specifically, a ceramic filter, a glass filter, a quartz filter Is appropriate.
[0018]
The dust trap filter is provided with a trap filter heater for heating the collected dust to cause a secondary generation reaction of dioxins or dioxin precursors. This heater is provided, for example, around the dust trapping filter. Specific examples include an electric heater, an electric furnace, a muffle furnace, and an electromagnetic heater.
[0019]
The concentrating tube is for adsorbing and collecting dioxins and dioxin precursors. The adsorbent used has only to have a performance of desorbing the adsorbed dioxins or dioxin precursor by heating in order to perform the analysis after the adsorption recovery. For example, 2,6-diphenyl-p-phenylene oxide resin (TENAX resin), graphite carbon-based particles, activated carbon and the like can be used.
[0020]
This concentrating tube is also provided with a concentrating tube heater for heating and desorbing dioxins and dioxin precursors adsorbed and collected. The heater may be an electric heater, an electric furnace, a muffle furnace, an electromagnetic heater, or the like, and is provided around the concentration tube.
[0021]
As an analyzer for analyzing the heat-desorbed dioxins or dioxin precursor, a gas chromatograph device, a laser ionizer, a vacuum ultraviolet light ionizer, an atmospheric pressure chemical ionizer, or the like can be used. Suitable examples of the column packing for the gas chromatograph include 100% dimethylpolysiloxane, 5% phenyl-methylpolysiloxane, and the like. Helium gas, argon gas or the like is appropriate as the carrier gas used. The detection of dioxins or dioxin precursors that are developed and flowed out by the gas chromatograph can be performed by an analyzer having a function of detecting and quantifying these, such as an electron capture detector (ECD). In addition to the ECD, a mass spectrometer, a flame flame ionization detector (FID), an electric conductivity detector (TCD), and the like can be used as the detector.
[0022]
In the method for measuring secondary dioxin production ability according to the present invention, exhaust gas containing dust is collected from a flue of an incinerator or the like, and is first cooled. The temperature of the collected exhaust gas is about 300 to 1000 ° C, usually about 300 to 850 ° C, and this is cooled to 300 ° C or less, preferably 150 ° C or less, particularly preferably 120 ° C or less. The lower limit of cooling is about 100 to 120 ° C, preferably about 100 ° C, from a practical point of view.
[0023]
The cooled exhaust gas collects dust contained therein. In the dust collecting step, an analyzer for analyzing the dioxins or dioxin precursor used in the present invention is connected, and the concentration of the dioxins or dioxin precursor in the exhaust gas component is analyzed at the time of collecting the dust. Can also be performed. In this case, since the concentrations of dioxins and dioxin precursors contained in the exhaust gas are generally very small, it is preferable that the concentration be increased by, for example, once being adsorbed by an adsorbent before analysis. After a predetermined amount of exhaust gas has been circulated to adsorb dioxins and dioxin precursors, the supply of exhaust gas is stopped, these are desorbed by heating or the like, and sent to the analyzer.
[0024]
The heating condition for desorption is about 250 to 300 ° C, preferably about 270 to 300 ° C for about 2 to 5 minutes. The desorbed dioxins and dioxin precursor are usually sent to an analyzer using an inert gas such as helium gas, argon gas, nitrogen gas or the like as a carrier gas. After the heating and desorption, the condensing tube can be used for the next measurement by purging it with an inert gas or the like in a heated state. Since dioxins and dioxin precursors generated in the secondary production reaction are extremely small, the exhaust gas collected from the flue is sent to the dust trap filter to collect dust while the above exhaust gas is being analyzed. It is preferable to continue.
[0025]
When a predetermined amount of exhaust gas is sent and the dust contained therein is collected by the dust capturing filter, the captured dust is heated to perform a secondary generation reaction. In this step, the capture filter on which the dust is captured is heated to 300 to 500C. The heating temperature is desirably 300 to 500C, which is the temperature at which the secondary generation reaction occurs, and more desirably, about 300 to 400C. As for the heating of the trapping filter, it is desirable to heat it quickly, but it is sufficient that the temperature reaches the set temperature in about 1 to 3 minutes. Regarding the time for performing the secondary production reaction, the secondary production reaction rate is said to proceed relatively slowly, and a reaction time of several hours is required. It is desirable that about 3 to 5 hours be the secondary production reaction time. It is desirable that the heating be performed in an oxygen (or air) atmosphere in a sealed state as much as possible, but the secondary generation reaction may be performed while flowing exhaust gas.
[0026]
Since the measurement of the secondary generation reaction by this dust is to determine the amount of dioxins generated in the actual machine, the measurement is repeated under the same conditions, and when the increase in the amount of dioxins generated is confirmed, Take measures.
[0027]
After completion of the secondary generation reaction, it is desirable that the dust in the trapping filter has a backwash line in consideration of semi-continuous measurement of secondary performance. At the end of the secondary generation reaction, backwashing and purging are performed from the backwashing line using an inert gas such as N ₂ gas, He gas, or compressed air. At this time, the dust in the trapping filter is returned to the flue through the sampling probe. Further, the backwash line may be prepared separately from the sampling line. In that case, a valve or the like may be provided between the sampling line and the backwash line. In this case, the dust in the trapping filter passes through the backwash line and is discharged out of the system by the backwash.
[0028]
【Example】
Example 1
FIG. 1 shows a schematic configuration of a dioxin secondary production ability measuring apparatus according to one embodiment of the present invention.
[0029]
As shown in FIG. 1, the apparatus includes a sampling probe 2 attached to an incinerator flue 1, a cooler 3 connected to the probe 2 for cooling an exhaust gas sample collected therefrom, A dust capturing filter 5 connected to the filter 3 for capturing dust contained in the exhaust gas sample; a concentrating tube 10 connected to the filter 5 for concentrating the components of the exhaust gas from which the dust has been removed; And a gas chromatograph device 16 for analyzing the exhaust gas component adsorbed on the substrate. Heaters 6 and 11 are attached to the filter 5 and the concentration tube 10, respectively. The inside of the concentration tube 10 is filled with 0.5 ml of TENAX TA (particle size: 35/60 mesh, manufactured by GL Science). A detector (ECD) 17 is provided in the gas chromatograph device 10 (column filler: 5% phenyl-methylpolysiloxane).
[0030]
A switching valve 4 is provided in a pipe connecting the cooler 3 and the filter 5, and a backwash line 9 leading to the flue 1 is branched therefrom. Two switching valves 8 and 12 are provided in a pipe connecting the filter 5 and the concentration pipe 10, and a pipe connected to the backwashing pump 7 branches from the switching valve 8 on the filter 5 side. The switching valve 12 on the side of the concentration pipe 10 is a four-way valve, and one of the pipes branched from the switching valve 12 is connected to a gas chromatograph device 16 and the other is connected to a sampling pump 20. A switching valve 18 is also provided on the outlet side of the concentration tube 10, and one of the pipes branched from the switching valve 18 is connected to a heating / desorption pump 14 and the other is connected to a sampling pump 15.
[0031]
Using the above apparatus, the secondary generation ability of dioxins in exhaust gas discharged from a waste incineration plant and dust contained therein was measured.
[0032]
The waste incineration facility where the measurement was performed was an incineration scale: 300 tons / day x 3 furnaces, and an existing continuous stoker furnace. Exhaust gas was collected from the flue 1 near the boiler outlet. First, the switching valve 4 is switched to the filter 5 side, the switching valves 8 and 12 are switched to the concentration pipe 10 side, and the switching valve 18 is switched to the sampling pump 15 side, and the sampling pump 15 is moved to discharge the exhaust gas at 1 L / min. At a flow rate of The exhaust gas temperature at this time was 500 ° C. The exhaust gas sampling time was 6 hours. The exhaust gas was cooled by the exhaust gas cooler 3 to 100 ° C. or lower, and then the dust was collected by the dust trap filter 5. Exhaust gas components not captured by the dust capture filter 5 were adsorbed by the concentration tube 10. The exhaust gas collection time in the concentration tube was 10 minutes.
[0033]
Next, the switching valve 12 is switched so that the outlet side of the filter 5 is connected to the sampling pump 20, the inlet side of the concentration tube 10 is connected to the gas chromatograph device 16, and the switching valve 18 is switched to the heating / desorption pump 14 side. Was. Therefore, the sampling pump 15 was stopped, and at the same time, the sampling pump 20 was operated to continue sampling of the exhaust gas. On the other hand, in order to analyze the exhaust gas component adsorbed on the concentration tube 10, the concentration tube 10 is rapidly heated to 300 ° C. by the heating / desorption heater 11, the heating / desorption line switching valve 18 is switched, and the heating / desorption pump 14 Was operated to send helium gas to the concentration tube 10. Thereby, the exhaust gas component desorbed by the rapid heating was introduced into the gas chromatograph device 16 through the analysis line 13, separated into the dioxin precursor component, and detected and quantified by the detector (ECD) 17. During the analysis period after the heat desorption, the line switching valve 12 was switched, and He gas was sent from the pump 20 to the concentration tube 10 to perform purging.
[0034]
After the analysis was completed, the line switching valve 12 was switched, the sampling pump 20 was stopped, and at the same time, the sampling pump 15 was operated again to adsorb the exhaust gas component in the concentration tube 10. This operation was repeated while sampling the dust for 6 hours. The time required for analyzing the exhaust gas components was 40 minutes including sampling. Exhaust gas component measurement was performed nine times before the dust sampling was completed.
[0035]
As a result, a dioxin precursor generated by a secondary generation reaction using only dust and exhaust gas and exhaust gas and a dioxin precursor generated by combustion were measured.
[0036]
Exhaust gas components during sampling include dioxin precursors generated by combustion, but since sampling is performed from the boiler outlet flue, dust and exhaust gas adhering to the flue from the combustion furnace outlet to the boiler outlet flue are removed. The contact causes a secondary production reaction. In addition, since the secondary generation reaction of the dioxin precursor occurs at the boiler outlet where the exhaust gas temperature becomes 500 ° C. or less even by the contact between the exhaust gases, the amount of the dioxin precursor in the exhaust gas component is generated by the above three kinds of reactions. Is measured as the sum of
[0037]
After the dust collection is completed (after 6 hours), the sampling pump 15 is stopped, the backwash switching valve 4 and the backwash line switching valve 8 are switched, and the dust trapping filter 5 is closed, and at the same time, The heater of the trap filter heater 6 was rapidly heated to 300 ° C. The secondary production reaction time was 5 hours. After the completion of the secondary production reaction, the backwashing switching valve 4 and the backwashing line switching valve 8 were switched, the sampling pump 15 was operated, and the exhaust gas component generated by the secondary production reaction was adsorbed on the concentration tube 10. The adsorption time was 30 minutes, and the detection and quantification of the dioxin precursor component was performed by the same operation as the measurement of the exhaust gas component after the adsorption.
[0038]
In order to remove and purge the dust trapped in the dust trap filter 5 after the completion of the secondary generation reaction, first, the temperature of the trap filter heating means is set to 500 ° C., and then the backwash switching valve 4 and the backwash line are switched. At the same time as switching the valve 8, the backwashing pump 7 was operated to perform backwashing. At the same time, He gas was purged from the backwashing pump 7. The backwashing and purging time was 1 hour.
[0039]
The time required for these series of measurements was 12 hours. In this example, continuous measurement was performed for 24 hours. That is, the secondary production ability was analyzed twice. Chlorobenzenes were measured as dioxin precursors, and the total value was calculated. Table 1 shows the results.
[0040]
[Table 1]

[0041]
[Table 2]

[0042]
Example 2
Based on the measurement results in Example 1, a secondary generation suppression operation of the waste incineration facility was performed. From the measured value of the dioxin precursor due to secondary formation, when the measured value is high (first time), at the end of the operation, the temperature at the outlet of the cooling tower is lowered by 20 ° C. from the normal, and at the same time, the activated carbon blowing amount is twice the normal blowing amount I drove it up. As a result, the measured value was reduced (second time), and the amount of dioxin precursor generated by the secondary production reaction could be reduced.
[0043]
【The invention's effect】
As described above, according to the present invention, a step of collecting exhaust gas containing dust from a flue of an incinerator or the like, a step of cooling the exhaust gas, a step of collecting dust in the exhaust gas, Measurement of dioxin secondary production ability, comprising the steps of heating the collected dust to perform a secondary production reaction of dioxins and dioxin precursors, and analyzing the dioxins and dioxin precursors generated by the secondary production reaction It is possible to measure not only the exhaust gas component but also the amount of dioxins generated by the secondary generation reaction in the exhaust gas treatment process, and it is possible to perform the operation for suppressing the secondary generation appropriately, and the dioxins Emissions are constantly reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a dioxin secondary production ability measuring apparatus according to one embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Incinerator flue 2 ... Sampling probe 3 ... Exhaust gas cooler 4 ... Backwash switching valve 5 ... Dust capture filter 6 ... Capture filter heater 7 ... Backwash pump 8 ... Backwash line switching valve 9 ... Backwash line DESCRIPTION OF SYMBOLS 10 ... Condenser tube 11 ... Heating / desorption heater 12 ... Line switching valve 13 ... Analysis line 14 ... Heating / desorption pump 15 ... Sampling suction pump 16 ... Gas chromatograph apparatus 17 ... Detector (ECD)
18: heating / desorption line switching valve 19: exhaust line 20: suction pump for sampling

Claims (3)

A sampling probe for collecting exhaust gas containing dust from a flue such as an incinerator, an exhaust gas cooling unit for cooling the collected gas, and a dust trapping filter for collecting dust in the cooled exhaust gas, A capture filter heater for performing a secondary generation reaction of dioxins or dioxin precursors by dust collected by the capture filter, and adsorbs dioxins or dioxin precursors generated from the capture filter after the secondary generation reaction A concentrating tube for recovery, a condensing tube heater for heating and desorbing the concentrated dioxins or dioxin precursor by heating the condensing tube, and an analysis for analyzing the thermally desorbed dioxins or dioxin precursor Device for measuring secondary production of dioxins characterized by comprising a device A step of collecting exhaust gas containing dust from a flue such as an incinerator, a step of cooling the collected exhaust gas, a step of collecting dust in the exhaust gas, and a step of heating the collected dust to dioxins and A method for measuring the secondary production of dioxins, comprising a step of performing a secondary production reaction of a dioxin precursor, and a step of analyzing dioxins and the dioxin precursor generated by the secondary production reaction. The method for measuring a secondary dioxin generation ability according to claim 2, wherein the exhaust gas component after the collection of the dust is analyzed while collecting the dust in the exhaust gas.

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