JP3698682B2 - Decontamination treatment method for buildings, equipment and devices inside waste incineration facilities - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is used, for example, when dismantling / removing a waste incineration facility, and highly efficiently and easily contaminates the inside of buildings and equipment / devices contaminated by harmful substances such as dioxins. The present invention relates to a decontamination method for the inside of buildings, equipment, and devices that can safely remove detrimental substances of concentration without discharging them to the outside.
[0002]
[Prior art]
The buildings that make up the waste incineration facility and the various equipment and devices installed inside the building are easily contaminated by harmful substances such as dioxins and heavy metals generated by the waste incineration, especially the exhaust gas from the waste incinerator. The interior of the exhaust gas cooling chamber and the exhaust gas treatment apparatus that are directly handled tends to be highly contaminated by harmful substances such as dioxins as the operation period of the waste incineration facility is longer.
[0003]
Therefore, when dismantling and removing garbage incineration facilities, etc., it is necessary to prevent environmental pollution and ensure the safety of workers. Strict regulations are set by laws and regulations on the level of protection of methods and protective clothing worn by workers.
[0004]
On the other hand, various techniques have been developed and disclosed so far in order to make it possible to dismantle and remove buildings and equipment / devices contaminated with the above-mentioned harmful substances in a safer, quicker and cheaper manner.
FIG. 6 shows an example of the prior art relating to this kind of decontamination treatment. In FIG. 6, A is an equipment storage room (object to be treated) that is an object of decontamination treatment, and B and C are curing conditions. Equipment (temporary enclosure), D ₁ and D ₂ are sealed passages, E is an air shower room, F is a changing room, M is a worker, S is sand, H is cement, P is cement solidified material, V is a vacuum suction device , G is a blast gun, N is a contaminant, 20 is a compressor, 21 is a sandblasting device, 22 is an air filter for a mask, 23 is a vacuum cleaner, 24 is an air duct, 25 is a dust collecting air cleaner, and 26 is a mortar mixer , 27 is a formwork.
[0005]
For the decontamination processing inside the equipment storage chamber A, first, an air-tight curing facility (temporary enclosure) B / C, an air shower room E, a changing room F, etc. are provided, and a sealed passage D _1. connected by D _2.
In addition, necessary equipment such as a compressor 20, a sandblast gun 21, a mask air filter 22, a vacuum cleaner 23, an air duct 24, a dust collecting air purifier 25, a mortar mixer 26, a formwork 27 and the like are installed, and an air hose L ₁ connecting between devices each other by · L ₂ and the like.
Furthermore, the worker M wears a protective protective suit, chemical protective gloves, chemical protective boots, an air line mask, etc. having a protective level prescribed by laws and regulations, and prepares a protective system.
[0006]
Once the above curing / preparation work is completed, the decontamination process begins. First, water is sprayed on the outer surface of the part where the contaminant N (hazardous substance) such as the wall surface or floor surface of the equipment storage chamber A is adhered, and the adhered contaminant N is moistened. Although the water spray device is omitted in FIG. 6, the water spray device to be used may be any type of spray device.
[0007]
When the operation of wetting the contaminant N is completed, the sand blasting device 21 is then operated, and the contaminant N adhering to the wall surface and the like is peeled off and dropped by a so-called blasting method using a blast gun G.
In addition, the contaminant N peeled off or dropped from the wall surface is sucked using the vacuum suction device V, collected in the vacuum cleaner 23 by a combination of so-called vacuum suction and air transport, and then sequentially accumulated in the curing equipment C. Go.
[0008]
Contaminant N accumulated in the curing equipment C is kneaded with cement H or the like in a mortar mixer 26 together with cleaning wastewater generated in the equipment storage chamber A, and solidified into a predetermined form using a mold 27 Is done.
Moreover, the solidified cement solidified material P is finally sent to a management-type industrial waste final disposal site where it is disposed of in landfill.
[0009]
The conventional decontamination processing method as shown in FIG. 6 can decontaminate the interior of the contaminated equipment storage chamber A and the like relatively efficiently, and has excellent practical utility.
However, many problems to be solved still remain in the contamination removal processing method.
[0010]
That is, in the conventional decontamination processing method, the harmful contaminant N adhering to the inner wall surface of the equipment storage chamber A is peeled and removed, and the removed high-concentration contaminant N is removed to the outside. Since it requires a detoxification process to reduce the contamination concentration of the extracted high-contamination contaminant N to a value within the legally regulated range by cement solidification, etc., a lot of work and time are required for the decontamination process There is a difficult point.
[0011]
Further, since it is necessary to once carry out the high-concentration contaminant N to the outside of the equipment storage chamber A, there is a risk of causing environmental pollution outside the equipment storage room A.
[0012]
Furthermore, although the high-concentration contaminant N taken out to the outside is detoxified by lowering the contamination level and cement solidifying, etc., waste for finally landfilling the formed cement solidified P Since a final disposal site is required, securing the final disposal site is a problem.
[0013]
[Problems to be solved by the invention]
The present invention is a building or equipment of a conventional waste incineration facility. The above-mentioned problem in the decontamination processing method inside the apparatus, that is, (1) separation / removal of adhered contaminants and removal process to the outside, and detoxification treatment process of the high-concentration contaminants carried out are necessary. Therefore, it is intended to solve the problems such as the fact that the decontamination process takes a lot of work and time, and (2) there is a risk of causing environmental pollution outside the object to be treated. In addition to removing and removing harmful contaminants and detoxifying treatments in parallel, the detoxified contaminants are transported to the outside when cleaning the inside of the object to be treated. The object of the present invention is to provide a decontamination method for the inside of a building or equipment / device in a waste incineration facility that can significantly improve work safety and work efficiency.
[0014]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a sealed heating step for raising the internal space of the object to be processed, which is in a substantially sealed state, to a predetermined temperature, and non-decomposition for decomposing dioxins into the heated sealed space. Decomposing agent blowing / spraying process for blowing the thermal decomposition agent, and cleaning the internal space after blowing the decomposition agent with high-pressure water to remove and remove the attached contaminants, and to remove dioxins by the non-thermal decomposition agent The basic structure of the invention includes a primary cleaning process for promoting a decomposition reaction and a secondary cleaning process for cleaning the interior space where the decomposition reaction is completed with water and discharging contaminants after the decomposition reaction to the outside. .
[0015]
According to a second aspect of the present invention, in the first aspect of the invention, the heating temperature in the sealing and heating step is set to 50 ° C to 80 ° C.
[0016]
According to a third aspect of the present invention, in the first aspect of the invention, after the completion of the primary cleaning step, the secondary cleaning step is started after a period of at least 30 minutes.
[0017]
According to a fourth aspect of the present invention, in the first aspect of the invention, the non-thermal decomposition agent of dioxins is used as the decomposition agent of the powdery substance, and the decomposition agent is sent into the internal space by air transportation. It is intended to be sprayed.
[0018]
According to a fifth aspect of the present invention, in the primary cleaning step of the first aspect of the invention, heavy metals in the contaminant are fixed in the contaminant after the decomposition reaction of the dioxins is completed.
[0019]
The invention according to claim 6 is the invention according to claim 1, wherein the weight of the non-thermal decomposition agent for dioxins blown into the sealed space is about 20 to 30% of the weight of the contaminants present in the sealed space. It is what you do.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a work process diagram of a decontamination processing method inside a building, equipment or apparatus according to the present invention, FIG. 2 is an equipment layout diagram in a sealing and heating process, and FIG. 3 is a decomposition agent blowing and spraying process. FIG. 4 is an equipment layout diagram in the primary cleaning process, and FIG. 5 is an equipment layout diagram in the secondary cleaning process.
[0021]
Referring to FIG. 1, the present invention is a sealed heating that heats the internal space of a building or equipment / device that is an object A to be processed held in a sealed state to a predetermined temperature (about 50 ° C. to 80 ° C.). Step 1, a decomposing agent blowing / spraying step 2 for blowing and spraying a predetermined amount of non-thermal decomposition agent of dioxins into the internal space of the object A to be sealed and heated, and washing the internal space with high-pressure water As a result, the pollutant layer containing harmful substances fixed on the wall surface etc. is moistened and peeled / dropped off, and the mixture of the pollutant and the sprayed / sprayed non-thermal decomposition agent and the decomposition reaction of dioxins by the decomposition agent A primary cleaning step 3 that promotes water, and a secondary cleaning step 4 that discharges contaminants in the internal space that have been rendered harmless to a predetermined safety level by mixing with a decomposition agent and a decomposition reaction by water cleaning, and It is composed of
[0022]
Examples of the object to be treated A include various buildings and various devices and apparatuses installed in the incineration facility.
Further, when the object A to be processed is a building or the like and its interior is divided into appropriate sections, the present invention is applied to each section, and the internal space is decontaminated.
Further, when the object A to be processed is a building or the like and the internal volume of one section is extremely large, the interior is divided into appropriate sections by a temporary wall or the like, and the decontamination process is performed for each section.
[0023]
The internal space of the object A to be processed is heated to about 50 ° C. to 70 ° C. by heat from a heating source such as an electric heater or a gas heater after each opening is closed with an appropriate shielding material.
In addition, when exhaust in the internal space at the time of heating is necessary, it is desirable to exhaust using a so-called local exhaust device such as a dust collection type air purifier.
[0024]
In addition, the inside space of the object A to be treated is heated to a temperature of about 50 ° C. to 70 ° C. because the adhering force is increased by drying contaminants containing harmful substances such as dioxin adhering to the wall surface. Reduced and easily removed and dropped by high-pressure water washing in the next process, enhanced decomposition reaction of the decomposition agent (powder) blown in the next process, and fine particles into the contaminant layer This is to allow deeper penetration.
Further, the temperature inside the space is more convenient as the temperature is higher, but the upper limit is about 80 ° C. from the viewpoint of economy and working time.
Further, when the temperature is 50 ° C. or lower, there may be a problem in terms of lowering the adhering force of the contaminants and adsorbability of the decomposition agent. Therefore, it is desirable that the temperature during heating is 50 ° C. or higher.
[0025]
In the decomposing agent blowing / dispersing step 2, a predetermined amount of the dioxin non-heat decomposing agent is blown / sprayed into the internal space of the object A to be treated using a powder blowing apparatus or the like.
The non-thermal decomposition agent is desirably blown as uniformly as possible by a so-called pneumatic transportation system, and therefore, it is desirable to provide a plurality of blowing ports.
Further, it is desirable to stop the exhaust from the internal space during the blowing of the non-thermal decomposition agent. However, if necessary, the exhaust is performed using a local exhaust device as in the case of the sealed heating step 1.
[0026]
The non-thermal decomposition agent reacts with and decomposes dioxins contained in pollutants and lowers the concentration of dioxins in the pollutants below a predetermined safe concentration level to make them harmless. It is. In the present embodiment, the trade name Diomaster (manufacturer Miura Kogyo Co., Ltd., distributor Alstom Power Co., Ltd.) is used as the non-thermal decomposition agent.
[0027]
In addition, the said non-thermal decomposition agent is exhibiting the fine powder form, and has a calcium compound as a main component.
Moreover, if it is dioxins contained inside fly ash etc., it will be said that it is about 80 to 85% by adding the non-thermal decomposition agent of 25-30 wt% of fly ash weight with water, and knead | mixing. A high decomposition rate of dioxins can be obtained.
In addition, the amount of non-thermal decomposition agent blown in the interior space of the object to be treated in the decontamination treatment of ordinary waste incinerator-related equipment / devices and buildings from the viewpoint of reaction rate and economy. Experiments have confirmed that a decomposition agent in an amount of 20 to 30 wt% of the amount of contaminants may be blown and sprayed.
[0028]
In the present invention, the weight of the contaminant containing dioxins existing in the internal space of the object A to be treated is calculated in advance, and the non-heated dioxins of about 20 to 30 wt% of the contaminant weight are calculated. The decomposition agent is blown and sprayed.
By blowing a non-thermal decomposition agent of about 20 to 30 wt% of the pollutant weight, the concentration of dioxins present in the interior of ordinary waste incineration facilities and equipment / devices is 20 ng. Contaminants of -TEQ / g or less can be reduced to a concentration that can be processed into a managed final disposal site of 3 ng-TEQ / g or less.
Of course, when the concentration of dioxins contained in the contaminant to be treated is relatively low, the amount of the non-thermal decomposition agent blown and sprayed may be reduced.
[0029]
The primary cleaning step 3 removes the contaminants fixed on the wall surface with high-pressure water, and mixes and agitates the contaminants and the non-thermal decomposition agent of the dioxins blown and sprayed earlier to dioxins. Promotes the decomposition reaction.
The amount of high-pressure water for primary cleaning is selected to be about 2 to 3 L per unit surface area of the object A to be treated when the stack thickness of contaminants is about 10 mm and the discharge pressure is 20 kg / cm ² .
The water discharge amount (l / m ² ) is appropriately changed depending on the stacking thickness of contaminants, the fixing strength thereof, the water discharge pressure, and the like. Usually, when the water pressure is 10 to 20 kg / cm ² , the water discharge amount is ^{2 to 5} l / m ^2. Of high pressure water is released.
[0030]
In the primary cleaning step 3, the polluted material that has been peeled off and dropped off, the dioxin non-thermal decomposition agent adhering to the water, and water are kneaded by the discharge of high-pressure water, thereby dioxins in the pollutant. As described above, it is possible to obtain a decomposition rate of up to about 85% under ideal conditions.
[0031]
The time required for the decomposition reaction of dioxins by the non-thermal decomposition agent is about 10 to 20 minutes, but it is desirable to put a time of about 30 to 60 minutes between the start of the next step.
[0032]
Dioxins are decomposed by a non-thermal decomposition agent by replacing Cl of dioxins with an alkyl group by an organic synthesis reaction.
In addition, by mixing the non-thermal decomposition agent additive with the contaminants, heavy metals such as lead contained in the contaminants are fixed in the decomposition products, and so-called stabilization of heavy metals is achieved at the same time. It has been confirmed by experiments that this can be done. The mechanism for immobilizing heavy metals is that the chelating agent contained in the additive binds to the metal ion to form a chelate compound and is immobilized in the reaction product.
[0033]
When the decomposition reaction of dioxins in the primary washing step 3 is completed, the secondary washing step 4 is started, and the detoxified contaminants are washed and discharged with water.
In the secondary cleaning step 4, high-pressure water having a water pressure of 30 to 40 kg / cm ² and about 10 to 40 l / min is ejected, and the detoxified contaminants are almost completely discharged to the outside of the object to be treated. Is done.
In the secondary cleaning step 4, it goes without saying that in addition to the usual water cleaning, another method for discharging detoxified contaminants may be used in combination.
[0034]
【Example】
2 to 5 show the gas cooling chamber 5 provided in the exhaust gas system when dismantling and removing a mechanized batch combustion type (separate gas cooling chamber type) waste incinerator (waste treatment amount 50 T / D, 20 years operation). The case where the decontamination treatment is performed according to the present invention is shown.
The gas cooling chamber 5 has an internal volume of about 90 m ³ (the inner wall surface has a surface area of about 150 m ² ), and an air preheater 6 is provided on the downstream side thereof.
In addition, a pollutant N having an average thickness of 8 to 12 mm is fixed in a laminated manner on the inner wall surface of the gas cooling chamber 5, and the average dioxin concentration before treatment of the pollutant N fixed on the inner wall surface is further increased. Was 7 ng-TEQ / g, and the elution value of the heavy metals of the pollutant was 5 mg / l for lead and its compounds.
[0035]
First, in the sealing and heating step 1, as shown in FIG. 2, the exhaust gas inlet side and the outlet side are sealed with a shielding material 7, and an electric heater 8, a kerosene jet heater 9 and a local exhaust device 10 are provided, Heating was performed until the internal space temperature of the cooling chamber 5 reached about 50 ° C. The time required for heating was about 120 minutes.
Further, during heating, the inside of the gas cooling chamber 5 was exhausted at a rate of about 0.5 m ³ / min, which was cleaned by the local exhaust device 10 and released into the atmosphere.
[0036]
Next, in the non-thermal decomposition agent blowing / spraying step 2, the powdery dioxins non-thermal decomposition agent K is transferred into the gas cooling chamber 5 from the portable powder blowing device 11 which has been installed in advance. Spouted and sprayed.
Decomposition agent K outlets 12 are selected at two locations, with a total amount of 110 kg (room surface area of about 150 m ² × contaminant thickness 0.01 m × contaminant specific gravity of about 300 kg / m ³ × 0.25). K was blown and sprayed uniformly into the gas cooling chamber 5 in about 120 minutes. In addition, the used dioxin non-thermal decomposition agent K is the above-mentioned Diomaster (trade name).
In FIG. 2, 11a is a blower, 11b is a transport pipe, 11c is a storage tank, and 11d is a quantitative feeder.
[0037]
When the decomposition agent blowing / spraying step 2 is completed, a worker M who has prepared protective measures as shown in FIG. 4 enters the gas cooling chamber 5 and jets high-pressure water W from a separately provided pressurizing pump (not shown). By doing so, the fixed substance layer of the contaminants to which the decomposition agent K adhered to the outer surface was sequentially peeled off and dropped off.
The water pressure of the high-pressure water W used was about 20 kg / cm ² , and the water discharge amount was about ² L per 1 m ² of the inner wall surface of the gas cooling chamber 5 (inner wall surface 150 m ² × 2 l / m ² = 300 l).
The total work time required for the primary cleaning step 3 was about 60 minutes, and thus the flow rate of the high-pressure water W was 5 l / min.
[0038]
After the completion of the primary washing step 3, the secondary washing step 4 was started as shown in FIG.
The worker M who has entered the gas cooling chamber 5 thoroughly cleans off the pollutant Q after the decomposition reaction remaining on the inner wall surface, and discharges the pollutant Q after the decomposition reaction that has dropped off to the floor surface into the discharge path 13. Then, it is washed out into the collection tank 14 provided outside the gas cooling chamber 5.
In this example, about 20 l of high-pressure water W was used per 1 m ² of the inner wall surface of the gas cooling chamber 5 (inner wall surface 150 m ² × 20 l / m ² = 3 ton). The total work time required for the secondary cleaning step 4 was about 75 minutes, and therefore the flow rate of the high-pressure water W was 40 l / min.
[0039]
When the decontamination process is performed according to the above embodiment, the dioxin concentration of the pollutant Q discharged into the recovery tank 14 after the decomposition reaction is about 1 ng-TEQ / g, which is reduced to about 1/7. Was.
Also, heavy metals such as lead are in a so-called fixed state in the pollutant Q after the decomposition reaction, and the concentration of lead and its compounds in the waste water in the recovery tank 14 is a standard value of 0.3 mg / l or less.
Furthermore, according to the result of the test of measuring the elution ratio of heavy metal from pollutant N before the decomposition reaction and contaminant Q after the decomposition reaction into water, the latter elution amount is about 30% less than the former elution amount. It has been confirmed that it is reduced to 1/500.
[0040]
【The invention's effect】
In the present invention, as described above, after carrying out the detoxification treatment inside the object to be treated without taking out the dangerous contaminant N containing dioxins as it is outside the object to be treated, This is configured to discharge to the outside. As a result, the risk that the external environment is contaminated by the contaminant N having a high dioxin concentration is greatly reduced.
[0041]
In the present invention, the contaminant N is peeled and dropped and the contaminant N is decomposed and rendered harmless in the primary cleaning step. As a result, the work time required for the decontamination process can be greatly reduced.
[0042]
Furthermore, the decontaminated contaminant Q discharged from the object to be treated is sufficiently agitated and mixed with a large amount of washing water in the secondary washing step 4. As a result, the contamination concentration of the contaminant Q after being decomposed and discharged to the outside is averaged so-called substantially uniformly, and there is no spot in the contamination concentration.
The present invention has excellent practical utility as described above.
[Brief description of the drawings]
FIG. 1 is a work process diagram illustrating an embodiment of the present invention.
FIG. 2 is a diagram for explaining the implementation of a sealing and heating step constituting the present invention.
FIG. 3 is an implementation explanatory diagram of a decomposition agent blowing / dispersing step constituting the present invention.
FIG. 4 is a diagram for explaining an implementation of a primary cleaning process constituting the present invention.
FIG. 5 is a diagram for explaining the execution of a secondary cleaning process constituting the present invention.
FIG. 6 is an explanatory diagram of a conventional decontamination processing method.
[Explanation of symbols]
A is an object to be treated, W is high-pressure water, N is a contaminant, K is a dioxin non-thermal decomposition agent, Q is a contaminant after decomposition reaction, 1 is a closed heating process, 2 is a decomposition agent blowing and spraying process 3 is a primary cleaning process, 4 is a secondary cleaning process, 5 is a gas cooling chamber, 6 is an air preheater, 7 is a shielding material, 8 is an electric heater, 9 is a kerosene jet heater, 10 is a local exhaust device, 11 Is a portable powder blowing device, 11a is a blower, 11b is a transport pipe, 11c is a storage tank, 11d is a metering feeder, 12 is a blowing port, 13 is a discharge passage, and 14 is a recovery tank.

Claims (6)

A sealing and heating step for raising the internal space of the object to be processed in a substantially sealed state to a predetermined temperature, and a decomposition in which a non-thermal decomposition agent for decomposing dioxins is blown into the heated sealed space. The primary cleaning that promotes the decomposition reaction of dioxins by non-thermal decomposition agent while cleaning the inside space after blowing agent and spraying agent with high-pressure water to remove the attached contaminants and drop off Contamination of buildings, equipment, and equipment in a waste incineration facility comprising a process and a secondary cleaning process in which the interior space where the decomposition reaction has been completed is washed with water and contaminants after the decomposition reaction are discharged to the outside. Removal processing method. The method for removing contamination inside a building, equipment or apparatus in a waste incineration facility according to claim 1, wherein the heating temperature in the sealed heating step is 50 ° C to 80 ° C. The method for removing decontamination of buildings, equipment, and devices in a waste incineration facility according to claim 1, wherein the secondary cleaning step is started after a period of at least 30 minutes after the completion of the primary cleaning step. The waste incineration treatment facility according to claim 1, wherein a non-thermal decomposition agent for dioxins is used as a powder decomposition agent, and the decomposition agent is sent into the internal space by air transportation and blown and sprayed. Decontamination method for buildings and equipment / devices in Japan. The building, equipment and device in the waste incineration facility according to claim 1, wherein heavy metals in the pollutant are fixed in the pollutant after completion of the decomposition reaction of dioxins in the primary cleaning process. Internal decontamination method. The waste incineration treatment facility according to claim 1, wherein the weight of the non-thermal decomposition agent for dioxins blown into the sealed space is about 20 to 30% of the weight of the contaminants present in the sealed space. Decontamination treatment method for buildings, equipment, and equipment.

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