JP2011206659A - Device and method for treating hazardous substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To treat a hazardous substance included in polluted soil etc. by checking the transfer of the substance to an exhaust gas.SOLUTION: The polluted soil 16 containing a hazardous substance and a carbide 18 which catches fire and heats, and can adsorb the hazardous substance, are mixed by a mixer 36. The mixed soil 20 is produced and introduced into a heating treatment part 14 inside a heating furnace 12. The heating furnace 12 includes an air suction port 22 for heating treatment, and the sucked air passes through the heating treatment part 14. The air for heating treatment is supplied to the carbide 18 included in the mixed soil 20 as heating air, and at the same time, works to make an adsorption of the hazardous substance included in the air, into the porous adsorption part of the carbide 18. Then, the air passing through the heating treatment part 14, is exhausted from a discharge port 24 of the heating furnace 12. The discharge port 24 is connected to a duct 26, to the end part of which a blower 30 for suction is fitted, and a carbide-based adsorption material 28 is set in place between the discharge port 24 of the duct 26 and the blower 30.

Description

  The present invention relates to a hazardous substance processing apparatus and a hazardous substance processing method.

  Conventionally, most of contaminated soil and contaminated sediment containing PCBs and dioxins harmful substances have been treated by the method shown in FIG. That is, the contaminated soil or the contaminated sediment 60 is put into the heating furnace 62 and indirectly heated (400 ° C. to 700 ° C.) inside the heating furnace 62 to remove harmful substances from the soil and sediment by pyrolysis and volatilization. To do. The purified soil and sediment 64 are taken out from the heating furnace 62 and reused. On the other hand, harmful substances that have been thermally decomposed and volatilized by indirect heating are sent to the exhaust gas processing unit 66, where they are processed by thermal decomposition means such as high-temperature combustion or superheated steam decomposition in the exhaust gas processing unit 66.

However, this processing method has a problem that much energy is consumed by indirect heating, high-temperature combustion, or the like.
Therefore, a technique for reducing energy consumption and purifying efficiently has been proposed (Patent Document 1).

According to Patent Document 1, as shown in FIG. 9, the contaminated soil 60 containing dioxins is heated in a heating furnace 62 to be oxidatively decomposed and rendered harmless. At this time, smectite clay mineral 68 such as montmorillonite or bentonite having an X-ray diffraction image peculiar to montmorillonite, acid clay or activated clay is mixed with contaminated soil 60 and supplied to heating furnace 62 together for oxidation. Let the decomposition process.

In this method, when the cause of the contaminated soil 60 is based on incinerated fly ash, that is, the harmful substances contained in the soil are mainly polychlorinated dibenzo-para-dioxin (PCDD _S ) or polychlorinated dibenzofuran (PCDF _S ). It is effective in some cases.

However, when the cause of the contaminated soil 60 is based on polychlorinated biphenyl (PCB _S ), that is, when the soil contains a high concentration of PCB _S , the atmosphere in the heating furnace 62 is oxidative and the heating temperature When the temperature is from 400 ° C. to 500 ° C., PCDF _S is produced as a by-product, which may increase toxicity.

As a method for suppressing the by-production of PCDF _S , it is necessary to increase the heating temperature to 600 ° C. or higher, or to reduce the atmosphere in the heating furnace 62. However, when the heating temperature is set to a high temperature of 600 ° C. or higher, the energy required for heating increases and the processing cost increases. On the other hand, when the atmosphere in the heating furnace 62 is reduced, tar derived from organic matter is generated in the contaminated soil 60 and the heating furnace 62 may be clogged. Further, a lot of energy is consumed in the exhaust gas processing unit 66.

JP 2008-92547 A

  In view of the above facts, an object of the present invention is to treat harmful substances contained in contaminated soil and the like while suppressing the shift to exhaust gas.

  The hazardous substance processing apparatus according to the first aspect of the present invention is ignited with contaminated incineration waste that is contaminated soil, contaminated sediment, or ash after incineration containing at least one of PCB and dioxin hazardous substances. The mixing device that mixes the carbides that generate heat and adsorb the harmful substances, and the mixing device, mixed soil, mixed sediment or mixed incineration waste is input, and the carbides are ignited to generate heat and the harmful A heating furnace provided with a heat treatment unit for heat-treating a substance, and air for heat treatment sucked from a suction port of the heating furnace are passed between the carbides of the heat treatment unit, and then the heating furnace And an air suction device for discharging from the discharge port.

  According to the first aspect of the present invention, in the mixing device, contaminated soil, contaminated sediment or incinerated waste containing harmful substances are mixed with carbides that are ignited and generate heat and can adsorb harmful substances. And mixed soil, mixed sediment or mixed incineration waste is generated.

  And mixed soil, mixed sediment, or mixed incineration waste is thrown into the heat treatment part of a heating furnace. Heat treatment air sucked from the suction port by the air suction device is introduced into the heat treatment unit. The air for heat treatment passes between the carbides that are ignited by the heat treatment portion and generates heat, and is discharged from the discharge port.

  Thus, if the carbide on the suction side is ignited to generate heat, the harmful substance adsorbed on the carbide is thermally decomposed and the harmful substance contained in the mixed soil is also thermally decomposed.

  The thermally decomposed harmful substances, the by-produced harmful substances, and some harmful substances volatilized without being thermally decomposed move to the outlet side together with the air passing between the carbides. In the middle of the movement, it is adsorbed by unignited carbide on the outlet side.

As a result, harmful substances can be thermally decomposed by the heat generated by the carbides while adsorbed on the carbides. In addition, volatilized harmful substances and harmful substances by-produced by thermal decomposition can be sequentially adsorbed to unignited carbides in the heat treatment section, and into the air (exhaust gas) discharged from the discharge port of the harmful substances Can be suppressed.
In addition, the carbide | carbonized_material should just be a substance which can adsorb | suck a harmful substance, and it is ignited and adsorb | sucks red while adsorbing a harmful substance, for example, plastics, coconut husk, activated carbon, sewage sludge etc. are mentioned.

  According to a second aspect of the present invention, in the hazardous substance processing apparatus according to the first aspect, the air suction device includes a blower and a ventilation path connecting the blower and the discharge port. The path is provided with an adsorbing means for adsorbing the harmful substances and by-product substances that are pyrolyzed or volatilized with the heat generation of the carbide.

  According to the second aspect of the present invention, the toxic substance contained in the air discharged from the discharge port is adsorbed by the adsorption means provided in the ventilation path between the discharge port and the air suction device. As a result, harmful substances released from the heating furnace to the atmosphere can be reduced.

According to a third aspect of the present invention, in the hazardous substance processing apparatus according to the second aspect, the adsorbing means is a carbide-based adsorbent.
Thereby, a toxic substance, its by-product substance, etc. can be adsorbed and held by the countless porous part which a carbide type adsorbent has.

  According to a fourth aspect of the present invention, in the contaminant treatment apparatus according to the third aspect, the carbide is the carbide-based adsorbent obtained by adsorbing the harmful substance and the by-product substance. .

  That is, a carbide-based adsorbent obtained by adsorbing harmful substances and by-product substances is used as a carbide that is ignited to generate heat and adsorb harmful substances. Thereby, the carbide can be effectively used.

  Invention of Claim 5 is a hazardous substance processing apparatus of any one of Claims 1-4. WHEREIN: The said mixed soil, the said mixed sediment, or the said mixed incineration waste thrown into the said heat processing part The carbide is ignited at the end on the suction port side.

  According to the invention described in claim 5, the carbide mixed in the mixed soil, the mixed sediment, or the mixed incineration waste introduced into the heat treatment unit is ignited from the end on the suction port side and generates heat. To start. Thereby, while the carbides generate heat, harmful substances are sequentially pyrolyzed from the suction port side to the discharge port side. That is, thermal decomposition proceeds by internal heating due to self-heating of carbide, and it is not necessary to input heating energy from the outside.

  The hazardous substance processing method according to the invention of claim 6 is ignited with contaminated incineration waste which is contaminated soil, contaminated sediment or ash after incineration containing at least one of PCB and dioxin harmful substances. The mixing step of mixing the carbide that can absorb the harmful substances with the mixing device, the mixed soil, the mixed bottom sediment or the mixed incineration waste is put into the heat treatment part of the heating furnace, and the air suction device A heat treatment step of igniting the carbide while passing the air for heat treatment sucked from the suction port of the heating furnace, and heat-treating the harmful substance by heat generation of the carbide; and the heating An adsorption step in which the harmful substances and by-product substances pyrolyzed or volatilized in the treatment step are sucked from the discharge port of the heating furnace by the air suction device and adsorbed to the carbide-based adsorbent for adsorption treatment. It is characterized in that.

That is, contaminated soil and carbides are mixed in the mixing step, and the carbides are ignited from the suction port side to generate heat and heat the harmful substances in the heat treatment step. At the same time, thermally decomposed or volatilized harmful substances are adsorbed on the carbide on the outlet side. Finally, harmful substances discharged from the discharge port in the adsorption step are adsorbed on the carbide-based adsorbent.
As a result, the harmful substance can be thermally decomposed by the heat generated from the carbide while adsorbed on the carbide, and the harmful substance can be treated while suppressing the transfer of the harmful substance to the exhaust gas.

The invention according to claim 7 is the hazardous substance processing method according to claim 6, wherein the carbide-based adsorbent used in the adsorption step and adsorbed with the harmful substance and the by-product substance is mixed in the mixing step. It is characterized by using as said carbide mixed with.
Thereby, the carbide type adsorbent used in the adsorption step can be effectively used.

  The invention according to claim 8 is the hazardous substance processing method according to claim 6 or 7, wherein the suction of the carbide mixed with the mixed soil, the mixed sediment, or the mixed incineration waste in the heat treatment step. The heat treatment is started by igniting from the mouth side, and the harmful substance and the by-product substance which are pyrolyzed or volatilized are sequentially adsorbed on the carbide on the outlet side.

  As a result, the heat treatment proceeds while causing the harmful substances contained in the contaminated soil and the like to be sequentially adsorbed and held on the carbide on the discharge port side, so that the transfer of the harmful substances to the exhaust gas can be suppressed and processed. .

  Since the present invention is configured as described above, harmful substances contained in contaminated soil and the like can be treated while suppressing the shift to exhaust gas.

It is a figure which shows the basic composition of the harmful substance processing apparatus which concerns on embodiment of this invention. It is a figure which shows the basic composition of the experimental apparatus used for the effect verification experiment of the harmful substance processing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the experimental result of the effect verification experiment of the harmful substance processing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the experimental result of the effect verification experiment of the harmful substance processing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the experimental result of the effect verification experiment of the harmful substance processing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the experimental result of the effect verification experiment of the harmful substance processing apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the experimental result of the effect verification experiment of the harmful substance processing apparatus which concerns on embodiment of this invention. It is a figure which shows the basic composition of the harmful substance processing apparatus of a prior art example. It is a figure which shows the basic composition of the harmful substance processing apparatus of a prior art example.

(First embodiment)
As shown in FIG. 1, the hazardous substance processing apparatus 10 according to the first embodiment includes a mixing apparatus 36. The mixing device 36 mixes the contaminated soil 16 containing at least one harmful substance of PCB or dioxins with the carbide 18 that is ignited and generates heat and can adsorb the harmful substance to generate the mixed soil 20.

  The mixed soil 20 is put into a heating furnace 12 that heats the mixed soil 20. The heating furnace 12 is formed into a hollow shape with a heat-resistant member, and the mixed soil 20 is heat-treated by the heat treatment unit 14 provided inside.

  A suction port 22 that sucks air for heat treatment is provided at one end of the heating furnace 12, and air for heat treatment is sucked into the heat treatment unit 14 from the suction port 22. The sucked air passes through the heat treatment unit 14 and is then discharged from the discharge port 24 provided in the heating furnace 12. At this time, the heat treatment air passes between the carbides 18 that are ignited by the heat treatment unit 14 and generate heat, and supplies the heat generation air to the carbides 18. At the same time, harmful substances contained in the air are adsorbed on the porous adsorption portion of the carbide 18.

  A duct 26 is connected to the discharge port 24, and a blower 30 that sucks air for heat treatment is attached to an end of the duct 26. A carbide adsorbent 28 is provided between the discharge port 24 side and the blower 30 side of the duct 26. That is, when the blower 30 is operated, air is sucked in the order of the suction port 22, the heat treatment unit 14, the discharge port 24, the duct 26, and the carbide-based adsorbent 28.

The carbide-based adsorbent 28 is thermally decomposed or volatilized with the heat treatment of the mixed soil 20 and adsorbs before releasing harmful substances and by-product substances discharged from the discharge port 24 together with the suction air to the atmosphere.
Then, the purified soil 21 from which harmful substances have been removed is taken out from the soil outlet 34 of the heating furnace 12.

  With this configuration, if the carbide 18 mixed in the mixed soil 20 is ignited from the suction port 22 side while the blower 30 is operating, the carbide 18 starts to generate heat. With this heat generation, the contaminated soil 16 mixed with the mixed soil 20 is heated, and harmful substances contained in the contaminated soil 20 are thermally decomposed. At this time, some of the harmful substances are volatilized without being thermally decomposed. A part of the pyrolyzed or volatilized harmful substance is desorbed from the mixed soil 20 and moves to the outlet 24 side (unignition side) together with the air passing between the carbides 18. At this time, it is adsorbed to the unignited carbide on the discharge port 24 side during the movement.

As a result, the transfer of harmful substances contained in the contaminated soil 16 to the suction air can be suppressed, and the harmful substances can be reduced.
In addition, although the contaminated soil containing a hazardous substance was explained as an example, it is not limited to this, the polluted incineration disposal which is the polluted sediment containing the hazardous substance or the ash containing the hazardous substance after incineration It can be a thing. That is, mixed bottom sediment mixed with contaminated sediment and carbide that is ignited and generates heat and adsorbs harmful substances, or contaminated incineration waste, and carbide that is ignited and generates heat and adsorbs harmful substances. Mixed incineration waste may be used.

Next, the hazardous substance processing method will be described.
The hazardous substance processing method is executed by the following procedure using the hazardous substance processing apparatus shown in FIG.
First, a mixing process is performed. In the mixing process, the mixing device 36 ignites the contaminated soil, the contaminated sediment or the contaminated incineration waste 16 containing at least one of PCB and dioxins, and can absorb the harmful substances. Carbide 18 is mixed.

  Next, a heat treatment process is performed. In the heat treatment step, the mixed soil, the mixed sediment, or the mixed incineration waste 20 generated in the mixing step is charged into the heat treatment unit 14 of the heating furnace 12. Then, the input mixed soil, mixed sediment, or mixed incineration waste 20 is heat-treated by the heat treatment unit 14. Specifically, the carbide 20 contained in the mixed soil, mixed sediment or mixed incineration waste is ignited from the suction port 22 side to generate heat.

  At this time, the carbide 18 generates heat while allowing air to pass around the carbide 18 by the blower 30. Thereby, the mixed soil, the mixed sediment or the mixed incineration waste 20 is heated from the suction port 22 side, and the thermally decomposed or volatilized harmful substances and by-products are turned into the unburned carbide 18 on the discharge port 24 side. Can be adsorbed.

  Next, an adsorption process is performed. In the adsorption process, harmful substances and by-product substances sucked by the blower 30 and discharged from the discharge port 24 are adsorbed on the carbide-based adsorbent 28 for adsorption treatment.

  As a result, harmful substances can be thermally decomposed by the heat generated by the carbide 18 while adsorbed by the carbide 18. In addition, the harmful substances volatilized and the by-products generated by thermal decomposition are adsorbed and retained by the carbide 18 on the discharge port 24 side, so that the amount of harmful substances contained in the suction air (exhaust gas) can be reduced. it can.

  The carbide-based adsorbent 28 that has already been used in the adsorption process and has adsorbed harmful substances and by-product substances can be used as the carbide 18 that is ignited and generates heat in the mixing process. Thereby, the carbide type adsorbent 28 can be used effectively.

Next, the effect will be described using demonstration experiment data.
FIG. 2 shows an experimental apparatus 40. The experimental device 40 has a hollow cylindrical shape and has a heating furnace 12 provided in the vertical direction. A heat treatment unit 14 is provided inside the heating furnace 12, and mixed soil 20 generated by mixing contaminated soil and carbide outside the heating furnace 12 is input to the heat treatment unit 14.

  An air suction port 22 for heat treatment is provided on the upper surface of the heating furnace 12, and a discharge port 24 is provided on the bottom surface of the heating furnace 12. A gravel layer 42 is provided on the bottom surface of the heating furnace 12, and the mixed soil 20 is put on the gravel layer 42. An ignition charcoal 44 is placed on the mixed soil 20. The charcoal 44 is ignited by a burner at the start of the experiment.

  A duct 26 is connected to the discharge port 24, and a suction pump 38 that sucks air for heat treatment is attached to the tip of the duct 26. The duct 26 is provided with a carbide-based adsorbent 28 that adsorbs volatilized harmful substances and harmful substances by-produced by thermal decomposition. The carbide-based adsorbent 28 is removed depending on the experimental conditions (RUN1 and RUN2, which will be described later) for effect verification.

  Also, the duct 26 is arranged in three stages in series between the carbide-based adsorbent 28 and the suction pump 38 in order to adsorb the harmful substances contained in the air to be sucked and the cooling unit 42 for cooling the heated air. The adsorbents (XAD 1 to 3) 45 and the flow meter 46 for measuring the amount of air for heat treatment are attached.

In the experiment, first, a preliminary experiment (RUN1) was performed with a heat treatment time of 30 minutes. The experimental conditions were that the weight ratio of the carbide mixed in the mixed soil 20 (the ratio of the amount of the carbonized substance to the mixed soil mass) was 20%, and the average speed of the heat treatment air passing through the mixed soil 20 was 42 mm / second. . The adsorbent 45 was removed.
Moreover, the depth of the gravel layer 42 was 20 mm, and the depth of the mixed soil 20 thrown into the heat processing part 14 was 80 mm.
The weight ratio of the carbide mixed in the mixed soil 20 is appropriately determined depending on the type of contaminated soil, the degree of contamination, the type of carbide used, and the like.

Examples of experimental results are shown in FIGS.
FIG. 3 shows the temperature change of the mixed soil 20s thrown into the heat treatment unit 14 for 30 minutes after being ignited. The horizontal axis is the elapsed time since ignition, and the vertical axis is the temperature at the measurement point. The ignition was performed in a state where the charcoal 44 was heated by the burner and reddish, and the experiment started from this state.

  In FIG. 3, a characteristic T1 indicated by a broken line indicates a temperature change of the mixed soil 20 20 mm below the upper surface of the mixed soil 20, and a characteristic T2 indicated by a two-dot chain line indicates that the mixed soil 20 is 40 mm below the upper surface of the mixed soil 20. A characteristic T3 indicated by a broken line indicates a temperature change of the mixed soil 20 60 mm below from the top of the mixed soil 20, and a characteristic T4 indicated by a one-dot chain line indicates a temperature change 80 mm below the top of the mixed soil 20 (with the gravel layer 42 and The characteristic T5 which shows the temperature change of the mixed soil 20 of (boundary of) is shown by the continuous line has shown the average temperature of the measurement points T1-T4, respectively.

  The characteristics T1 to T5 gradually increase with the lapse of time, the characteristic T2 has the highest temperature (up to about 750 ° C.), and the characteristic T4 has the lowest temperature. The average temperature was about 400 ° C to 450 ° C. The reason why the temperature rise of the characteristic T1 is small is thought to be due to cooling with suction air. In addition, a temperature measurement point is a soil part in the mixed soil 20, and the inside of the red-heated carbide is estimated to be a higher temperature.

FIG. 4 shows the measurement result of the PCB concentration change. The horizontal axis indicates a typical measurement place through which the suction air passes, and the vertical axis indicates the total amount of PCB (μg).
The resulting bar graph shows the total amount stacked for each number of chlorine contained in the PCB. Symbol a is one chlorine, symbol b is two, symbol c is three, symbol d Indicates 4 PCBs, 5 symbol e, 6 symbol f, 7 symbol g, 8 symbol h, 9 symbol i, and 10 symbol j PCB. .

  From the results, as shown in the bar graph P1, the total amount of PCB contained in the contaminated soil before the heat treatment was 455 μg. After the heat treatment, as shown in the bar graph P2, the total PCB amount in the upper half (sample upper layer) of the mixed soil 20 is 30 μg, and as shown in the bar graph P3, the PCB total amount in the lower half of the mixed soil 20 (sample upper layer) is 240 μg, As shown in the bar graph P4, the total PCB amount of gravel is 10 μg or less, and as shown in the bar graphs P5 and P6, the total PCB amount in the suction air adsorbed by the adsorbents (XAD1 to 3) 45 is 10 μg or less. Since XAD3 did not adsorb at all, the description was omitted.

  From this result, it can be seen that even if the PCB is heat-treated, it does not move to the suction air side. Moreover, although it is reducing greatly in the upper half of the mixed soil 20, it is not yet fully thermally decomposed in the lower half of the mixed soil 20. This is presumably because the heat treatment time is short and the thermal decomposition has not progressed to the lower half of the mixed soil 20. A separate confirmation experiment with a longer heat treatment time was conducted. The result of the confirmation experiment will be described later.

In FIG. 5, the measurement result of the density | concentration change of dioxins is shown. The horizontal axis indicates the measurement location, and the vertical axis indicates the total amount of dioxins (pg). Note that the bar graph is a result of stacking by dividing the detected dioxins by symbols a to j.
Here, symbol a is T ₄ CDDs of dioxins, symbol b is P ₅ CDDs, symbol c is H ₆ CDDs, symbol d is H ₇ CDDs, symbol e is O ₈ CDD, and symbol f is T _4. CDFs, symbol g represents P ₅ CDFs, symbol h represents H ₆ CDFs, symbol i represents H ₇ CDFs, and symbol j represents O ₈ CDF.

  From the results, as shown in the bar graph D1, the total amount of dioxins in the contaminated soil was about 190,000 pg before the treatment. After the treatment, the total amount of dioxins in the upper half of the mixed soil 20 is 80,000 pg as shown in the bar graph D2, and the total amount of dioxins in the lower half of the mixed soil 20 is 15,000 pg, as shown in the bar graph D3, the bar graph D4. The total amount of dioxins in gravel is 220,000 pg or less, and the total amount of dioxins in suction air is 220,000 pg or less as shown in bar graphs D5 and D6.

  From this result, it can be seen that dioxins are not transferred to the suction air side even when the heat treatment is performed. Moreover, although it has reduced to half or less in the upper half of the mixed soil 20, it is not fully thermally decomposed in the lower half of the mixed soil 20. However, with respect to the reduction of dioxins, as in the case of PCB, satisfactory results can be obtained by increasing the heat treatment time as described later.

  FIG. 6 shows the result of a confirmation experiment using the same experimental apparatus as in FIG. 2 and extending the heat treatment time. The temperature change of each part for 120 minutes is shown after the mixed soil 20 thrown into the inside of the heat treatment part 14 is ignited. The horizontal axis is the elapsed time since ignition, and the vertical axis is the temperature at the measurement point.

  The temperature measurement points are also the same as in FIG. 3, and the characteristic T1 indicated by the broken line indicates the temperature change of the mixed soil 20 20 mm below the upper surface of the mixed soil 20, and the characteristic T2 indicated by the two-dot chain line indicates the upper surface of the mixed soil 20. The characteristic T3 indicated by a broken line indicates the temperature change of the mixed soil 20 below 40 mm from the top, and the characteristic T4 indicated by the one-dot chain line indicates the temperature change of the mixed soil 20 below 60 mm from above the mixed soil 20 by the dotted line. The characteristic T5 which shows the temperature change of the mixed soil 20 80 mm below (boundary with the gravel layer 42) from the solid line shows the average temperature of the measurement points T1 to T4.

Individual temperature changes are slightly different due to differences in local density of carbides, distances from the carbide at the temperature measurement point, etc., but as expected, the major trends are as follows: confirmed.
That is, the characteristics T1 and T2 of the upper layer of the mixed soil 20 rapidly increase with time, and maintain a temperature of 500 ° C. to 600 ° C. until about 90 minutes after ignition, and then gradually until 120 minutes after ignition. And reaches around 300 ° C.

In the characteristics T3 and T4 in the lower layer of the mixed soil 20, the temperature rise immediately after ignition is moderate, and the characteristic T4 increases rapidly at 90 minutes after ignition. And at about 120 minutes after ignition, the temperature reaches about 300 ° C. The average temperature was about 300 ° C to 400 ° C.

In FIG. 7, the measurement result of the PCB density | concentration in each part after progress for 120 minutes after ignition is shown. The horizontal axis shows the experimental conditions, and the vertical axis shows the PCB balance.
Here, RUN1 is the result of the preliminary experiment described above, and the air superficial velocity is 42 mm / sec, the processing time is 30 minutes, and no charcoal adsorption column is used. RUN2 is the air superficial velocity of 50 mm / sec, the processing time. RUN3 indicates each condition of an air superficial velocity of 42 mm / sec, a processing time of 120 minutes, and a charcoal adsorption column. In all of RUN 1 to 3, the mixing ratio of carbide was 20%.

That is, about 40% of the PCB contained in the contaminated soil before treatment (before ignition) is decomposed under the condition of RUN1, about 50% is contained in the lower layer of the sample, and about 7% is contained in the upper layer of the sample.
On the other hand, under the condition of RUN2, about 60% is decomposed, about 25% is contained in the exhaust gas, about 5% is contained in the ice-cooled part, and about 10% is contained in gravel.
Under the condition of RUN3, about 90% is decomposed, and the remaining about 10% is contained in the exhaust gas, the charcoal adsorption column, the lower layer of the sample, and the upper layer of the sample.

From this, under the condition of RUN2, the amount of decomposition increases from 40% to 60% by increasing the processing time from 30 minutes to 120 minutes. However, increasing the air superficial velocity from 42 mm / sec to 50 mm / sec increases the amount contained in the exhaust gas without being adsorbed by the carbide.
Therefore, as in the condition of RUN3, the air superficial velocity is set to 42 mm / sec, a charcoal adsorption column is provided, the PCB contained in the exhaust gas is recovered, and reused as a heating source to thermally decompose the attached PCB, It was confirmed that about 90% decomposition could be realized.

10 Toxic Substance Treatment Equipment 12 Heating Furnace 14 Heat Treatment Unit 16 Contaminated Soil (Contaminated Soil, Contaminated Sediment or Contaminated Incineration Waste)
18 Carbide 20 Mixed soil 22 Suction port 24 Discharge port 26 Duct (ventilation path, air suction device)
28 Carbide-based adsorbent (adsorption means)
30 Blower (Air suction device)
36 Mixing equipment

Claims (8)

Mixing contaminated soil containing contaminated soil, contaminated sediment, or ash after incineration, and carbides that are ignited and generate heat and can adsorb the harmful substances, containing PCB or dioxin harmful substances A mixing device to
From the mixing device, mixed soil, mixed sediment or mixed incineration waste is charged, and the carbide is ignited to generate heat, and a heating furnace provided with a heat treatment unit for heat-treating the harmful substances,
An air suction device for letting the air for heat treatment sucked from the suction port of the heating furnace pass through between the carbides of the heat treatment unit, and then discharge the air from the discharge port of the heating furnace;
Hazardous substance treatment equipment. The air suction device includes a blower and a ventilation path that connects the blower and the discharge port, and the ventilation path is thermally decomposed or volatilized due to heat generation of the carbides. The hazardous substance processing apparatus according to claim 1, further comprising an adsorption means for adsorbing the by-product substance.   The hazardous substance processing apparatus according to claim 2, wherein the adsorption means is a carbide-based adsorbent.   The hazardous substance processing apparatus according to claim 3, wherein the carbide is the carbide-based adsorbent obtained by adsorbing the harmful substance and the by-product substance.   5. The carbide igniting means is provided at an end P portion on the suction port side of the mixed soil, the mixed sediment, or the mixed incineration waste charged into the heat treatment unit. The hazardous substance processing apparatus according to any one of claims. Mixing process of mixing contaminated soil, contaminated sediment or incinerated waste containing at least one hazardous substance of PCB or dioxins with carbide that is ignited and generates heat and can adsorb the harmful substance in a mixing device. When,
The mixed soil, mixed sediment or mixed incineration waste is put into the heat treatment section of the heating furnace, and the air for heat treatment sucked from the suction port of the heating furnace is passed between the carbides by the air suction device. A heat treatment step of igniting the carbide while heating, and heat-treating the harmful substance by heat generation of the carbide,
An adsorption process in which the harmful substances and by-product substances pyrolyzed or volatilized in the heat treatment process are sucked from a discharge port of a heating furnace with the air suction device and adsorbed to a carbide-based adsorbent for adsorption treatment,
A method for treating hazardous substances.   The hazardous substance processing method according to claim 6, wherein the carbide-based adsorbent used in the adsorption step and adsorbed with the harmful substance and the by-product substance is used as the carbide mixed in the mixing step.   In the heat treatment step, the carbide mixed in the mixed soil, the mixed sediment or the mixed incineration waste is ignited from the suction port side, and the heat treatment is started, and the harmful substances and pyrolysis or volatilized by the pyrolysis or volatilization are started. The hazardous substance processing method according to claim 6 or 7, wherein the product substance is sequentially adsorbed on the carbide on the discharge port side.

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