JP3645237B2 - Recycling method of adsorbents in processing facilities for pollutants contaminated with organohalogen compounds - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for regenerating an adsorbent in a treatment facility for pollutants contaminated with an organic halogen compound, and more particularly, to pollutants such as sludge and soil contaminated with an organic halogen compound such as polychlorinated biphenyl (PCB). The present invention relates to a method for regenerating an adsorbent used in a processing facility for processing.
[0002]
[Prior art]
As is well known, polychlorinated biphenyl, a kind of organic halogen compound, is very stable and difficult to be decomposed, and has high insulation (electrical resistance), so in the past, insulation materials such as transformers and capacitors, and heat media Or it was used for carbonless copy paper, but now it is prohibited to use for environmental reasons.
[0003]
However, there are cases where traces remain in solids such as soil and sludge even if they have been used for some time, and how to decompose and treat them is an important issue. It has become.
[0004]
As a means for decomposing and treating such polychlorinated biphenyls, there is a treatment method using incineration means. However, this incineration may cause another harmful substance such as dioxin, which is also a viewpoint of environmental destruction and safety. Is not always sufficient, and at present, materials containing this compound and waste are not treated.
[0005]
Therefore, as one means for solving this problem, the inventors made the invention of Japanese Patent Application No. 2002-30292 and filed a patent application.
[0006]
In this invention, a pollutant contaminated with an organic halogen compound is heated in a reducing atmosphere, and the organohalogen compound in the exhaust gas generated from the pollutant by heating is adsorbed and treated with activated carbon as an adsorbent. .
[0007]
[Problems to be solved by the invention]
In this method, exhaust gas generated by heating in a reducing atmosphere is passed through cleaning oil so that the cleaning oil absorbs the organic halogen compound in the exhaust gas, and further, the exhaust gas is passed through an activated carbon adsorption tower into the exhaust gas. The remaining organic halogen compound is adsorbed on the activated carbon.
[0008]
Since this cleaning oil is passed through this activated carbon, substances such as oil mist are adsorbed in addition to the above organic halogen compounds. It is necessary to replace it with new activated carbon.
[0009]
The actual situation is that the activated carbon having reduced adsorption capacity is treated as industrial waste. As a result, the amount of waste increases, and even if a trace amount of organic halogen compound such as polychlorinated biphenyl remains on the activated carbon, there is a risk of environmental destruction.
[0010]
The present invention has been made to solve such problems, and reduces the amount of industrial waste as described above and also reduces the amount of activated carbon used, thereby reducing the cost for processing. Is an issue.
[0011]
[Means for Solving the Problems]
The present invention has been made to solve such a problem, and means for solving the problem is to heat a pollutant contaminated with an organic halogen compound in a reducing heating apparatus 1 in a reducing atmosphere. In the treatment facility for pollutants contaminated with organic halogen compounds, the organic halogen compounds in the exhaust gas generated from the pollutants in the reduction heating apparatus 1 by heating are adsorbed by the adsorbent in the adsorption apparatus 4 and processed. An adsorbent whose adsorption power is reduced by adsorbing an organic halogen compound in the adsorption device 4 is supplied to the reduction heating device 1 and heated in a reducing atmosphere to desorb an adsorbate from the adsorbent, and the adsorbent. Is to play.
[0012]
In this case, the adsorbent can be activated by blowing water vapor into the adsorbent from which the adsorbate has been desorbed by heating in a reducing atmosphere.
[0013]
Furthermore, it is possible to decompose the organic halogen compound adsorbed on the adsorbent by stirring the adsorbent supplied to the reduction heating apparatus 1 .
Further, the adsorption device 4 is provided with two filling chambers, a first filling chamber 13 and a second filling chamber 14, from the upstream side to the downstream side of the exhaust gas, and the adsorbent filled in the first filling chamber 13 of the adsorption device 4 Is taken out and supplied to the reduction heating apparatus 1, the adsorbent in the second filling chamber 14 is transferred to the first filling chamber 13, and the second filling chamber 14 is filled with the adsorbent after regeneration or a new adsorbent. It is also possible.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
(Embodiment 1)
First, a treatment facility for treating contaminated soil contaminated with polychlorinated biphenyl, which is an example of an organic halogen compound, will be described as an embodiment.
[0016]
As shown in FIG. 1, the treatment facility includes a reduction heating device 1, an oil scrubber 2, a dechlorination device 3, and an activated carbon adsorption device 4.
[0017]
The reduction heating apparatus 1 performs a dechlorination process by reduction heating, and includes a cylindrical heating apparatus body 5 as shown in FIG. The reduction heating apparatus 1 has a passage for supplying air and nitrogen gas, and a rotary shaft 6 is rotatably mounted in a substantially central longitudinal direction. A plurality of paddle blades 7 are attached to the rotating shaft 6.
[0018]
In addition, a storage portion 9 for storing a heat medium made of combustion gas fed by the blower 8 is formed on the outer peripheral portion of the heating device body 5. A heat exchanger 10 is provided at the subsequent stage of the heating device body 5.
[0019]
The oil scrubber 2 is for supplying exhaust gas from the reduction heating device 1 to extract and collect polychlorinated biphenyl in the cleaning oil.
[0020]
The dechlorination apparatus 3 adds a sodium dispersant in which metallic sodium powder is dispersed in an insulating oil, and decomposes and dechlorinates polychlorinated biphenyl in the cleaning oil supplied from the oil scrubber 2. The dechlorination apparatus 3 is further added with water, isopropyl alcohol, or the like, which is a reaction promoting substance.
[0021]
A vacuum distillation tank 11 is provided between the dechlorination apparatus 3 and the oil scrubber 2 as shown in FIG. This vacuum distillation tank 11 is for removing water in the washing oil in advance by vacuum distillation before reacting polychlorinated biphenyl with metallic sodium.
[0022]
Further, a hydration tank 12 is provided on the rear stage side of the dechlorination apparatus 3 as shown in FIG. The hydration tank 12 is for hydrating the sodium dispersant that has not been consumed in the dechlorination apparatus 3.
[0023]
The activated carbon adsorbing device 4 is for passing the exhaust gas discharged from the oil scrubber 2.
[0024]
As shown in FIG. 4, the activated carbon adsorption device 4 has two filling chambers, a first filling chamber 13 and a second filling chamber 14, extending from the upstream side to the downstream side of the exhaust gas.
[0025]
And the method of processing contaminated with polychlorinated biphenyl as an example of an organic halogen compound by the above processing equipment will be described.
[0026]
First, the contaminated soil to be treated is supplied to the reduction heating apparatus 1. In this reduction heating device 1, polychlorinated biphenyl is decomposed.
[0027]
More specifically, the contaminated soil is supplied to the heating device main body 5 of the reduction heating device 1, and the heating device main body 5 is also supplied with air and nitrogen gas and is heat-treated in a reducing atmosphere.
[0028]
In the heating apparatus main body 5, the rotating shaft 6 is rotated as shown in FIG. 2, whereby the contaminated soil is stirred by the plurality of paddle blades 7 attached to the rotating shaft 6. Thereby, a considerable amount of polychlorinated biphenyl in the contaminated soil is decomposed.
[0029]
The exhaust gas from the heating device main body 5 is supplied to the oil scrubber 2 as shown in FIG. 2, passes through the oil scrubber 2, and then is discharged through the activated carbon adsorption device 4. The function of the oil scrubber 2 will be described later.
[0030]
When polychlorinated biphenyl is contained in the exhaust gas discharged from the reduction heating device 1, it is supplied to the next dechlorination device 3 and decomposed.
[0031]
More specifically, the polychlorinated biphenyl contained in the exhaust gas discharged from the reduction heating apparatus 1 is first supplied to the oil scrubber 2 as shown in FIGS. The polychlorinated biphenyl is absorbed in the cleaning oil in the oil scrubber 2.
[0032]
Next, the cleaning oil in the oil scrubber 2 is supplied to the vacuum distillation tank 11 as shown in FIG. 3, but the water in the cleaning oil is distilled and removed in the vacuum distillation tank 11. This is to reduce the consumption of metallic sodium in the next step, and if the washing oil contains a large amount of water, the metallic sodium added later may react with the water to become caustic soda. In addition, since there is a possibility that the reaction between metallic sodium and polychlorinated biphenyl may be hindered, moisture is removed in advance by vacuum distillation.
[0033]
Next, the cleaning oil from which moisture has been removed in the vacuum distillation tank 11 is supplied to the dechlorination unit 3 as shown in FIG. 3, and polychlorinated biphenyl is decomposed by the metallic sodium added to the dechlorination unit 3. Is done.
[0034]
That is, a sodium dispersant in which metal sodium powder is dispersed in an insulating oil is added to the dechlorination apparatus 3, and the metal sodium in the sodium dispersant reacts with the polychlorinated biphenyl in the cleaning oil, resulting in polychlorination. Biphenyl is dechlorinated and decomposed.
[0035]
Excess metal sodium not consumed in the dechlorination apparatus 3 is supplied to the hydration tank 12 as shown in FIG. In the hydration tank 12, water is supplied and unconsumed metallic sodium is hydrated.
[0036]
The cleaning oil (regenerated oil) separated in the hydration tank 12 is returned to the oil scrubber 2.
[0037]
The polychlorinated biphenyl is dechlorinated and decomposed by the reduction heating apparatus 1 and the dechlorination apparatus 3 as described above. The polychlorinated biphenyl in the exhaust gas from the reduction heating apparatus 1 and the oil mist from the cleaning oil, etc. Is adsorbed on the activated carbon of the activated carbon adsorbing device 4, so that the adsorptive power of the activated carbon gradually decreases with the use of a certain time.
[0038]
Then, although it is necessary to replace | exchange the activated carbon in which the adsorption power fell with the new activated carbon, embodiment of the method of supplying and reproducing | regenerating the activated carbon in which the adsorption power fell to the reduction heating apparatus 1 is described according to FIG.
[0039]
As described above, the activated carbon adsorption device 4 is provided with the two filling chambers of the first filling chamber 13 and the second filling chamber 14, but the upstream side of the activated carbon in the second filling chamber 14 on the downstream side. The activated carbon in the first filling chamber 13 adsorbs more adsorbate.
[0040]
Therefore, first, the activated carbon filled in the first filling chamber 13 of the activated carbon adsorption device 4 is taken out and supplied to the reduction heating device 1, and the activated carbon in the second filling chamber 14 is transferred to the first filling chamber 13. The second filling chamber 14 is filled with activated carbon after regeneration or new activated carbon, which will be described later.
[0041]
On the other hand, the activated carbon with reduced adsorptive power supplied to the reduction heating apparatus 1 is heated in the reduction atmosphere in the reduction heating apparatus 1. At this time, in the heating apparatus main body 5, the rotating shaft 6 is rotated as described above, and the activated carbon is stirred by the plurality of paddle blades 7, whereby the polychlorinated biphenyl adsorbed on the activated carbon is decomposed. , Will be detached from the activated carbon.
Even if a very small amount of polychlorinated biphenyl remains without being desorbed from the activated carbon, it is decomposed by reduction heat treatment.
[0042]
Oil mist and other organic substances are also desorbed from the activated carbon by heat treatment in the above reducing atmosphere.
[0043]
Therefore, the activated carbon from which such polychlorinated biphenyl, oil mist, and the like are released becomes regenerated and is filled in the activated carbon adsorbing device 4 as described above and can be reused.
[0044]
The polychlorinated biphenyl that has been desorbed from the activated carbon but not decomposed in the reduction heating apparatus 1 is contained in the exhaust gas discharged from the reduction heating apparatus 1 as in the case of polychlorinated biphenyl in the soil as described above. Then, the oil is supplied to the dechlorination apparatus 3 via the oil scrubber 2 and the vacuum distillation tank 11 and is decomposed by metallic sodium.
[0045]
Thus, in this embodiment, since the activated carbon used in the activated carbon adsorption device 4 can be regenerated using the reduction heating device 1 for performing the decomposition treatment of polychlorinated biphenyl, the activated carbon can be regenerated. There is no need to perform this work separately.
[0046]
In addition, the polychlorinated biphenyl adsorbed and remaining on the activated carbon is dechlorinated and decomposed again by the reduction heating device 1 and the dechlorination device 3, so that the polychlorinated biphenyl is discharged out of the system. It can prevent more reliably.
[0047]
Moreover, the amount of industrial waste can be reduced by regenerating activated carbon by reduction heating as described above.
[0048]
Furthermore, since the activated carbon can be suitably regenerated as described above, the amount of new activated carbon used can be reduced by filling the activated carbon adsorption device 4 again and reusing it.
[0049]
(Embodiment 2)
In this embodiment, as shown in FIG. 6, an activation device 15 for activating activated carbon that has been heated by the reduction heating device 1 and from which oil mist or the like as adsorbed material has been removed is provided. This is different from the first embodiment in which the activation device 15 is not provided.
[0050]
In the present embodiment, the regenerated activated carbon from which the oil mist or the like that is the adsorbed material has been desorbed is not immediately supplied to the activated carbon adsorbing device 4 but is first supplied to the activation device 15. Water vapor is supplied to the activation device 15, whereby adsorbates that have not been removed by the reduction heating device 1 are further removed.
The activation is performed while heating at a temperature of 800 to 1000 ° C. for about 3 to 30 minutes while blowing water vapor as described above.
[0051]
Then, the activated carbon activated by the activation device 15 is supplied to the activated carbon adsorption device 4 and reused in a state where the adsorption power is further recovered.
[0052]
In the present embodiment, the adsorbate is desorbed by heating with the reduction heating device 1, and the heat treatment is performed while blowing steam with the activation device 15, so the adsorbate that has not been completely removed by the reduction heating device 1. Therefore, the activated carbon can be reused in a state where the adsorption power is further recovered.
[0053]
(Other embodiments)
In the above embodiment, the activated carbon adsorbing device 4 has a structure having two filling chambers of the first filling chamber 13 and the second filling chamber 14 from the upstream side to the downstream side of the exhaust gas. The structure of the activated carbon adsorption device 4 is not limited to this. For example, the activated carbon adsorption device 4 having only one filling chamber may be used.
[0054]
Further, the structure of the reduction heating apparatus 1 is not limited to the structure including the cylindrical heating apparatus main body 5 as in the above embodiment and the rotating shaft 6 and the plurality of paddle blades 7.
[0055]
Furthermore, although the sodium metal used as a thing which makes polychlorinated biphenyl decomposition | disassembly reaction in the dechlorination apparatus 3 of the said embodiment has an advantage which is cheap and generally available easily, it is not restricted to this, Metal potassium, metal It is also possible to use strontium, metallic lithium or an alloy thereof. That is, a dispersant in which an alkali metal is dispersed in a dispersion medium such as oil may be used.
[0056]
Furthermore, although the case where polychlorinated biphenyl was treated was described in the above embodiment, the type of the organic halogen compound to be treated is not limited to the polychlorinated biphenyl of the above embodiment, for example, dioxin It may be.
[0057]
Further, it may be a coplanar PCB or the like.
[0058]
Here, the coplanar PCB is an isomer of PCB which has no chemical substitution at the ortho position (2, 2 ', 6 and 6'), and has only one or two tetrachlorides. Some of the above isomers are PCBs having a coplanar structure (coplanar), which are more toxic than ordinary PCBs and exhibit actions similar to those of dioxins.
[0059]
In short, it is sufficient that an organic halogen compound is contained in an object such as soil to be treated.
[0060]
Furthermore, in the said embodiment, although activated carbon was used as an adsorbent, the kind of adsorbent is not limited to this, It is also possible to use another adsorbent.
[0061]
Furthermore, although the case where it applied to contaminated soil was demonstrated in the said embodiment, the target object of this invention is not restricted to such soil, For example, it is also possible to apply this invention to things like contaminated sludge. is there.
[0062]
【The invention's effect】
As described above, the present invention is an organic material in which a pollutant contaminated with an organic halogen compound is heated in a reducing atmosphere, and the organic halogen compound in the exhaust gas generated from the pollutant by heating is adsorbed by an adsorbent. In a treatment facility for pollutants contaminated with a halogen compound, the adsorbent is heated in the reducing atmosphere to desorb the adsorbate from the adsorbent and regenerate the adsorbent. The amount of industrial waste of adsorbents such as activated carbon that has been generated can be significantly reduced, and the adsorbent can be regenerated using a reduction heating device to decompose organic halogen compounds. The decomposition process of the organic halogen compound can be promoted while using the material cyclically.
[0063]
Further, since the adsorbent can be regenerated using a reduction heating device for performing the decomposition treatment of the organic halogen compound, it is not necessary to separately perform an operation for regenerating the adsorbent.
[0064]
In addition, by regenerating the adsorbent by reduction heating, there is an effect that the adsorbent in a state where the harmful organic halogen compound is adsorbed is not discarded as industrial waste.
[0065]
Furthermore, since the adsorbent can be suitably regenerated and reused as described above, there is an effect that the amount of adsorbent used can be reduced as a whole.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of an apparatus for treating contaminants contaminated with an organic halogen compound as one embodiment.
FIG. 2 is a schematic block diagram of a reduction heating device and the like in the processing apparatus.
FIG. 3 is a schematic block diagram of a dechlorination apparatus and the like in the processing apparatus.
FIG. 4 is a schematic cross-sectional view of an activated carbon adsorption device in a processing apparatus.
FIG. 5 is a schematic block diagram of a processing apparatus showing a regeneration process of activated carbon.
FIG. 6 is a schematic block diagram of a processing apparatus according to another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Reduction heating apparatus 3 ... Dechlorination apparatus 4 ... Activated carbon adsorption apparatus 15 ... Activation apparatus

Claims (4)

A pollutant contaminated with an organic halogen compound is heated in a reducing atmosphere in a reduction heating device (1), and the organic halogen compound in the exhaust gas generated from the pollutant in the reduction heating device (1) is adsorbed by heating. (4) In a treatment facility for pollutants contaminated with an organic halogen compound to be adsorbed and treated by the adsorbent in the adsorbent, an adsorbent whose adsorbing power is reduced by adsorbing the organic halogen compound in the adsorption device (4) Supplying to the reduction heating device (1), heating in a reducing atmosphere, desorbing the adsorbate from the adsorbent and regenerating the adsorbent, Recycling method of adsorbent in processing equipment. The adsorbent in the treatment equipment for contaminants contaminated with an organic halogen compound according to claim 1 , wherein the organic halogen compound adsorbed on the adsorbent is decomposed by stirring the adsorbent supplied to the reduction heating device (1). How to play. The adsorption device (4) has two filling chambers, a first filling chamber (13) and a second filling chamber (14), from the upstream side to the downstream side of the exhaust gas, and the first filling of the adsorption device (4). The adsorbent filled in the chamber (13) is taken out and supplied to the reduction heating device (1), and the adsorbent in the second filling chamber (14) is transferred to the first filling chamber (13), and the second filling chamber. The method for regenerating an adsorbent in a treatment facility for a pollutant contaminated with an organic halogen compound according to claim 1 or 2, wherein the adsorbent after regeneration treatment or a new adsorbent is filled in (14). The pollutant contaminated with the organic halogen compound according to any one of claims 1 to 3 , wherein the adsorbent is activated by blowing water vapor into the adsorbent from which the adsorbate has been desorbed by heating in a reducing atmosphere. To regenerate adsorbents in various processing facilities.

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