JP2003194312A - Demolition working method of incineration facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent workers from being exposed to dioxins adhering to the inside of a facility in demolishing an incineration facility. <P>SOLUTION: There are provided a decontamination method and a demolition procedure for evaporating and decomposing the dioxins to reduce the exposure of the workers to the dioxins in the demolition by overheating a contact part of a combustion gas in demolishing the incineration facility. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a work method for dismantling a used incineration facility.

[0002]

2. Description of the Related Art Hazardous organic substances, especially dioxins (polychlorinated dibenzo-p-
Dioxin (PCDD), polychlorinated dibenzofuran (P
CDF) and coplanar PCB (co-PCB)) may adhere. When dismantling an incinerator that is contaminated with these organic substances, it is feared that harmful organic substances will be scattered along with the dust, and this dust will be inhaled into the human body, which will be harmful to health. Therefore, occupational health and safety regulations (Heisei 1
(April 25, 3rd)) When dismantling the incineration facility, analyze the work environment around the incineration facility and the deposits in contact with the combustion gas of the incinerator facility in advance, and disassemble according to the concentration of dioxins. The work area will be decided and the construction method and level of protective equipment will be decided. In addition, it is obligatory to remove the contaminants before dismantling regardless of the presence or absence of contamination.

The concentration of dioxins in the work environment at the dismantling site of the incineration facility is 2.5 pg-TEQ / m ³ or less, and the concentration of dioxins in the deposit is 3000 pg-TEQ.
/ G or less or when the contaminants are almost completely removed, the first control area for dismantling work, the concentration of dioxins in the working environment is 2.5 to 3.75 pg-TEQ / m ³ The concentration of dioxins is 3000-4500 pg-
In the case of TEQ / g, the concentration of dioxins in the dismantling work second control area and working environment is 3.75 pg-TE.
If the Q / m ³ or more, the concentration of dioxins in the deposit is 45
If the concentration is 00 pg-TEQ / g or more or the dioxin concentration is unknown, it will be the 3rd controlled area for dismantling work. The dismantling method and the equipment used are determined as follows according to the dismantling work management area.

(1) Demolition work first control area (level 1)
Then manually dismantle: Hand-held power tool, hydraulic crushing, shearing method: crusher, steel frame cutting machine, etc. Mechanical grinding method: cutter, wire saw, core drill, etc. Mechanical impact method: hand breaker, drilling machine,
Large breakers, etc. Expansion pressure, method by expanding holes: Static crushing agent, hydraulic hole expander, etc. Other methods: Water jet, abrasive jet, etc. Method by fusing: Gas cutting machine (2) Second dismantling work control area (level) In 2), the construction method by fusing cannot be used in the disassembling methods of (1) to. (3) Dismantling work Only the dismantling method and equipment that can be used in the third controlled area (Levels 3 and 4) are (1).

As for protective equipment, in the dismantling work first control area, a dust mask (level 1 compatible) and dismantling work second
In the controlled area, a full-scale dust and gas mask (level 2 compatible),
In the 3rd controlled area for dismantling work, airline masks or air-fighting confidential clothing (level 3 and 4 compatible) are used.

Since the dismantling work of the conventional incinerator is premised on the dismantling in the state where the contaminants are adhered, the sampling work of the contaminants, the removing work of the contaminants, the disassembling work, and the carrying work are carried out. There is concern about exposure to dioxins in each process. The concentration of dioxins is 3000
When treating pg-TEQ / g or more pollutants as industrial waste, special disposal is required as specific industrial management waste.

[0007]

Since the above-mentioned prior art is premised on that the incinerator to be dismantled has contaminants, the collection of deposits (deposits), the removal of deposits (deposits), and the dismantling There is a concern that workers will be exposed to dioxins in each unit work. In addition, if the concentration of dioxins in the deposit (deposit) is 3000 pg-TEQ / g or more, wearing of protective equipment with poor workability and usable work and equipment are restricted, so that the deposit (deposit) A large amount of money is required for each work such as sampling, removal of contaminants, dismantling, and waste disposal.

The present invention removes organic pollutants, particularly dioxins, in the deposits (deposits) deposited (deposited) on the contact portion of the combustion gas of an incinerator which is in operation or at rest, before the dismantling work. By doing so, it is intended to prevent the workers from being exposed to dioxins and reduce the dismantling cost in a series of operations such as sampling during dismantling, removal of contaminants, and dismantling. A further object of the present invention is to reduce the disposal cost of waste by disposing it as general industrial waste with a dioxin concentration of 3000 pg-TEQ / g or less in the waste generated after dismantling.

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned object, after removing deposits on a combustion gas contact part of an incineration facility, sampling of the work environment and deposits, analysis of dioxins, removal of contaminants, It is designed to vaporize and decompose harmful organic substances such as dioxins by heating the exhaust gas of the incineration facility while heating the exhaust gas of the incineration facility by heating the contact part of the combustion gas of the incinerator with a burner or the like.

According to the present invention, in a part of an incineration facility, a contact burner is brought into contact with combustion gas by heating it with a combustion burner to perform dioxin cleaning work on the contact, and then the work environment and the contact sample collected from the contact burner. Provided is a dismantling work method for an incineration facility, which performs analysis work including analysis of dioxins of a kimono, and then dismantles the incinerator.

Furthermore, the present invention reduces the level of the dismantling work management area by performing dioxin purification work on the contact portion that comes into contact with the combustion gas in the incineration facility part, and thereafter defines the disassembly work management area at that level. A method of dismantling an incineration facility for performing the dismantled work described above.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. Example 1 will be described with reference to the layout diagram of FIG. 1 in which a purifying device is attached to the small incineration facility.
In FIG. 1, 1 is a chimney, 2 is an incinerator, 3 is an ash outlet (dust input port), 4 is a secondary combustion cylinder, 5 is a secondary combustion burner (heating burner), 6 is a heating burner, 10 Is a flame introduction tube. The chimney 1 of the stopped incinerator 2 is covered with the secondary combustion cylinder 4, and the secondary combustion burner 5 is installed on the upstream side of the secondary combustion cylinder 4 of the chimney 1. Further, a heating burner 6 for heating the incinerator is installed at the ash outlet 3. The secondary combustion burner 5 may be separately arranged to introduce the combustion gas.

FIG. 2 is a work process diagram of the embodiment shown in FIG. First, the secondary combustion burner 5 attached to the chimney 1 is ignited (S
1), It is confirmed that the temperature of the exhaust gas of the secondary combustion cylinder 4 is 800 ° C. or higher (S2). Next, the heating burner 6 for heating the inside of the incinerator is ignited (S3), and it is confirmed that the temperature of the contact portion (furnace wall etc.) of the combustion gas becomes 550 ° C or higher (S3).
4). The secondary combustion cylinder and the furnace wall of the incinerator are maintained at a specified temperature for several tens of minutes (S5). Further, a flame introduction pipe 10 made of stainless steel is attached to the tip of each burner 5, 6. By installing this flame introduction tube 10, it is possible to prevent heat radiation and to make the temperature of the flame uniform.

Dioxins are polychlorinated dibenzo-p-
Dioxin (PCDD), polychlorinated dibenzofuran (P
CDF) and coplanar PCB (co-PCB) are generic terms, and physical properties differ depending on the number and position of chlorine added. PCDD has a boiling point of 315 to 510 ° C.,
PCDF 338-537 (Translated by Kansai Institute of New Technology, Dioxin, p37, NTS, (1999.
10)), co-PCB is 340 to 375 ° C (supervised by Ministry of Labor, Occupational Health Department, Chemical Hazard and Hazard Handbook, p162,
(December 1994)). That is, if the temperature of the attached substance to which the dioxins are attached is higher than the boiling point, the attached dioxins are easily evaporated. Further, the dioxin is decomposed by keeping the temperature of the exhaust gas at 800 ° C. for 2 seconds or more and further reducing the concentration of carbon monoxide in the exhaust gas to 100 ppm or less. (Law Enforcement Regulations on Waste Disposal and Cleaning (Revised 1998) Therefore, the temperature of the exhaust gas at the exhaust gas outlet (chimney) of the incineration facility should be kept at 800 ° C or higher for 2 seconds or longer in advance.
By making the temperature of the contact point of the combustion gas higher than the boiling point (550 ° C or higher), dioxins adhering to the contact point of the combustion gas evaporate and are carried to the secondary combustion tube (chimney) by the heating gas. To burn. As a result, dioxins adhering to the contact portion of the combustion gas in the incineration facility evaporate and decompose. That is, it is possible to burn dioxins evaporated during the purification work without releasing them into the environment.

According to this embodiment, organic substances, especially dioxins, deposited or attached to the contact portion of the combustion gas of the incineration facility are vaporized and decomposed. As a result, it is possible to reduce the exposure of workers to dioxin in each unit work during dismantling. Further, since the dioxin that has evaporated during the cleaning operation is burned by attaching the secondary combustion cylinder, it is possible to reduce the dioxin that is released to the environment.

The second embodiment will be described with reference to FIG. The same components as those in the embodiment shown in the drawings are designated by the same reference numerals, and the description thereof will not be repeated. In the second embodiment, description will be made with reference to the drawing showing the tip of the flame introduction port of the secondary combustion burner. The tip 10a of the flame introduction pipe 10 of the secondary combustion burner 5 is arranged to be in the same direction as the flow of exhaust gas (shown by an arrow). The same applies to the heating burner 6. The material of the flame introducing tube 10 may be stainless steel. By adopting such a structure, it is possible to achieve heat release and uniform flame temperature.

If the flame directly hits the chimney or the like, the members such as the chimney may be damaged by fusing, but this embodiment avoids the fusing of the members such as the chimney and ensures safety. Further, there is an effect that the temperature of the flame can be made uniform and the heat loss can be reduced.

[Embodiment 3] A purification apparatus for a small incineration facility equipped with a dust collector in the embodiment shown in FIG. 1 will be described with reference to FIG. In FIG. 4, 7 is a dust collector, and 6-2 is a heating burner B of the dust collector. FIG. 5 is a work process diagram of the embodiment shown in FIG. The same symbols are given to the same steps as the steps shown in FIG.

First, the secondary combustion burner 5 is ignited (S
1) Confirm that the temperature of the exhaust gas in the secondary combustion cylinder is 800 ° C. or higher (S2). Next, the heating burner 6 for heating the incinerator is ignited (S3) to make contact with the combustion gas (furnace wall, etc.).
It is confirmed that the temperature of is 550 ° C. or higher (S4).
The combustion gas of the secondary combustion cylinder 4 and the temperature of the furnace wall are maintained at 550 ° C. or higher for several tens of minutes (S5). After stopping the heating burner 6 of the incinerator, the temperature of the exhaust gas in the secondary combustion tube 4 is reduced to 8
While keeping the residence time at 00 ° C or higher for 2 seconds, the heating burner 6-2 of the dust collector is further ignited (S6), and the surface temperature of the contact part of the combustion gas of the dust collector becomes 540 ° C or higher. Is confirmed (S7). The temperature of the secondary combustion cylinder 4 and the furnace wall is maintained at the temperature of several tens of minutes (S8). in this case,
The heating temperature may be lower than 550 ° C, but it is necessary to lengthen the heating time.

Further, the heating burner 6 of the incinerator and the heating burner 6-2 of the dust collector may be ignited at the same time. in this case,
There is concern that the flow rate of the combustion gas becomes high, the residence time of the exhaust gas in the secondary combustion cylinder 4 becomes 2 seconds or less, and the decomposition rate of evaporating dioxins becomes low. Further, when there is a place where it is difficult to raise the temperature to 550 ° C. or higher in a large incineration facility or the like, it is preferable to heat the contact part of the combustion gas in the incinerator by dividing it into several parts.

According to this embodiment, since the method of heating the incineration facility by dividing it into several parts is adopted, a relatively small burner and secondary combustion cylinder can be used, and the initial cost of the purification equipment can be reduced. There is.

The fourth embodiment will be described with reference to FIG. Similar to the above, the same components as those shown in FIG. 5 are designated by the same reference numerals. In FIG. 6, 6-3 is a flue heating burner, 8 is a flue, and 9 is a flue.
Is a sample gas introduction pipe for analysis of dioxins and combustion gas. The experimental conditions are shown in Table 1.

[0023]

[Table 1]

In the incineration facility having an incineration capacity of 150 kg / h, the exhaust gas temperature of the secondary combustion cylinder and the temperature of the contact member of the combustion gas are raised to a high temperature as in the third embodiment. The combustion gas contact member was heated in the order of the incinerator 2, the flue 8, and the dust collector 7.
The exhaust gas from the secondary combustion cylinder was continuously sampled during heating to analyze dioxins and CO, O ₂ , and CO ₂ . In addition, the surface of the combustion gas of the secondary combustion cylinder and the surface of the contact member of the combustion gas 2-3
The temperature was measured by contacting a thermocouple at a depth of mm. Furthermore, the deposits adhering to the combustion gas contact member were collected before and after the experiment to analyze dioxins and carbon. The results are shown in Table 2.

[0025]

[Table 2]

The concentration of dioxins in the combustion gas is 0.12
It was ng-TEQ / m ³ . Since the emission standard for dioxins in the exhaust gas of an existing incinerator with a treatment capacity of less than 2 t / h since December 2002 is 10 ng-TEQ / m ³ , the value is significantly lower than the emission standard.

The composition of the combustion gas was such that CO was 100 ppm or less, oxygen was 11 to 14%, and CO ₂ was 5 to 7% in an oxygen excess flame, and dioxins were easily decomposed.

The dioxin concentration of the deposit is 8 before the treatment.
The value of 100 to 4500 pg-TEQ / g became a value of 100 pg-TEQ / g or less after the treatment. When dismantling the incineration facility, the concentration of dioxins in the deposit is 3
The work classification in the case of 000 pg-TEQ / g or less is the dismantling work first management classification, which is the safest work classification. Also,
Environmental standard for dioxins in soil is 1000 pg-T
There is EQ / g (250 pg-TEQ / g or higher requires monitoring). Therefore, even for adhered substances, 250 pg-TEQ / g
The following can be considered as safe as soil.

The carbon concentration in the deposit was several% before the treatment, but became 0.1% or less after the treatment. Since dioxins are organic compounds, if carbon does not exist as an index of the concentration of organic substances, dioxins do not exist. Empirically, if the carbon concentration becomes 0.1% or less, the concentration of dioxins will also be 250 pg-TEQ /
It becomes less than g and carbon becomes an index substance of dioxin concentration.

As a result of the above experiment, the concentration of dioxins in the exhaust gas is below the emission standard, and the dioxin concentration in the deposit is purified to 250 pg-TEQ / g or less,
It was also found that the carbon concentration was 0.1%. It was found that dioxins are not released into the environment during purification work.

According to the present example, it was confirmed that the amount of dioxins released during the cleaning operation was small and the effect of reducing the concentration of dioxins in the deposit was obtained. This was supported by the reduced amount of carbon in the deposit.

The disassembly procedure at the time of disassembly will be described collectively. Figure 7 shows the Occupational Safety and Health Regulations (Heisei 13.4.2
5 grants). Analyze the atmosphere (work environment) around the incineration facility and the deposits, and select the demolition work category, work method, and level of protective equipment to be used according to the concentration of dioxins. When the concentration of dioxins is less than the specified concentration (adhered matter 3000 pg-TEQ / g or more, working environment 2.5 pg-TEQ / m ³ ), the contaminants can be removed before disassembly. If the concentration is above the specified level, re-analyze to confirm that the concentration of dioxins is high. On the other hand, in the implementation procedure A of FIG. 8 showing the embodiment of the present invention, the ambient air (working environment) and the adhered substances are analyzed after the contact members of the combustion gas of the incineration facility are purified in advance to determine the dioxin concentration. After confirming that the concentration is lower than the concentration, the contaminants are removed and then disassembled. As in the conventional method, the dismantling procedure B in FIG. 9 analyzes the surrounding atmosphere (work environment) and adhered substances, purifies substances with a dioxin concentration higher than the specified concentration, and then removes contaminants before dismantling. is there. In the dismantling procedure C of FIG. 10, after cleaning the contact members of the combustion gas in the incineration facility in advance, the deposit is analyzed and the carbon concentration is 0.1% or the dioxin concentration is 250 pg-T.
If it is equal to or less than EQ / g, it is considered that there is substantially no contaminant and the method is dismantled as it is.

In the dismantling procedure A of FIG. 8, the contact members of the combustion gas are cleaned in advance, so that the operator is required to perform a series of operations such as sampling, removal of contaminants, dismantling, etc. as compared with the conventional method of FIG. It has the effect of reducing exposure to dioxins. In the dismantling procedure B of FIG. 9, since purification is performed when the dioxin concentration is high, there is an effect that the purification cost can be reduced when the dioxin concentration is low. In the dismantling procedure C of FIG. 10, after cleaning in advance, the deposit can be analyzed and dismantled as it is when the concentration of dioxins or carbon is below a certain concentration, so that there is an effect that the cost of the work of removing the contaminant can be reduced. .

As described above, by adopting the dismantling procedure A, the dismantling procedure B, or the dismantling procedure C, the dioxin purification work is performed on the contact portion that comes into contact with the combustion gas in the incineration facility, and the above-described dismantling work management is performed. Provided is a method for dismantling an incineration facility, which reduces the level of an area and then carries out the dismantling work specified in the dismantling operation management area of the level. In this case, as the most preferable dioxin cleaning operation, a method of heating each contact portion of the chimney, the dust collector, the flue and the incinerator with combustion gas individually can be adopted.

As a method for carrying out the present invention, the following dismantling work and purification method for an incinerator are provided. (Part 1) In the dismantling procedure of the incineration facility, the dismantling of the incinerator is characterized by the following steps: purification of combustion gas and contact area, work environment and analysis of dioxins after collecting deposits, removal of contaminants, disassembly procedure. (Part 2) In the dismantling procedure of the incineration facility, the disassembling procedure of the incineration facility is characterized in that the work of cleaning the contact portion with the combustion gas, working environment and analysis of dioxins after collecting deposits, and dismantling are performed in this order. (Part 3) In the dismantling procedure of the incineration facility, the work environment and the analysis of dioxin in the deposits, the heat purification of the contact part with the combustion gas, the dismantling procedure of the incinerator, which is characterized in that work is performed in this order. (Part 4) A method for cleaning an incineration facility, characterized in that the incineration facility is integrated or divided and heated in a heating furnace to evaporate and decompose organic matter attached. (No. 5) A method for purifying an incinerator, which comprises heating the temperature of the exhaust gas of the incinerator to 800 ° C or higher while heating the contact portion of the combustion gas of the incinerator to 550 ° C or higher. (Part 6) In the purification method for an incinerator of (4), the temperature of the exhaust gas of the incinerator is 800 ° C. or higher and the temperature of the contact portion of the combustion gas of the incinerator is partially heated while the residence time of the exhaust gas is 2 seconds or more. A method for cleaning an incineration facility, characterized in that the whole is heated to 550 ° C or higher and then the whole is heated in order. (Part 7) In the purification method of the incineration facility of 5 and 6,
A method for purifying an incineration facility, characterized in that a secondary combustion cylinder is attached to an exhaust gas emission part of the incineration facility. (Part 8) In the method for purifying an incinerator according to Part 7, a flame introduction pipe is attached to the secondary combustion burner, and the flow of the flame at the outlet of the introduction pipe is in the same direction as the combustion gas. Purification method. (Part 9) In the purification method of the incineration facility of 5-8,
A method for cleaning an incinerator, wherein the flame of the heat source is an excess oxygen flame. (No. 10) In the purification method for an incineration facility according to Nos. 5 to 7, the heating source is a solid fuel. (No. 11) In the dismantling procedure of the incineration facility of No. 2, the carbon concentration in the deposit adhered to the contact portion of the combustion gas is set to 0.1% or less, the dismantling procedure method of the incinerator. (No. 12) In the dismantling procedure of the incineration facility of No. 2, it is characterized in that the concentration of dioxins in the deposits adhering to the contact portion of the combustion gas is set to 250 pg-TEQ / g or less. Method.

[0036]

EFFECTS OF THE INVENTION The present invention removes dioxins in deposits accumulated or in contact with a combustion gas contact member of an incinerator by evaporation / decomposition, and then performs sampling, removal of contaminants, and dismantling work. As a result, the exposure of dioxins to workers in each unit work can be reduced. Further, by lowering the level of the dismantling work division at the time of dismantling, the level of protective equipment used can be lowered, and the dismantling work and equipment that can be used are less restricted, so that the dismantling cost can be reduced. Further, since the concentration of dioxins contained in the industrial waste generated during dismantling is low, there is an effect that the waste can be easily disposed.

[Brief description of drawings]

FIG. 1 is a layout view of a purifying device according to a first embodiment of the present invention.

2 is a work process diagram of FIG. 1. FIG.

FIG. 3 is a view showing a tip end of a flame introduction pipe which is a second embodiment of the present invention.

FIG. 4 is a layout view of a purification device for an incinerator having a dust collector according to a third embodiment of the present invention.

5 is a work process diagram of an incineration facility having the dust collector shown in FIG.

FIG. 6 is a layout view of a purification device of an incineration facility used in an experiment that is a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a dismantling procedure of a conventional incineration facility.

FIG. 8 is a diagram showing a dismantling procedure A of the incineration facility according to the embodiment of the present invention.

FIG. 9 is a diagram showing a dismantling procedure B of the incineration facility according to the embodiment of the present invention.

FIG. 10 is a diagram showing a dismantling procedure C of the incineration facility according to the embodiment of the present invention.

[Explanation of symbols]

1 ... Chimney, 2 ... Incinerator, 3 ... Ash outlet, 4 ... Secondary combustion cylinder, 5 ... Secondary combustion burner, 6 ... Heating burner, 6-2 ...
Dust collector heating burners, 6-3 ... Flue heating burners, 7
... Dust collector, 8 ... Flue, 9 ... Sample gas introduction pipe, 10 ... Flame introduction pipe, 10a ... Tip of flame introduction pipe.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yutaka Misawa             Hitachi, 3-10-3 Bentencho, Hitachi City, Ibaraki Prefecture             Kyowa Engineering Co., Ltd. (72) Inventor Akira Ichimura             Hitachi, 3-10-3 Bentencho, Hitachi City, Ibaraki Prefecture             Kyowa Engineering Co., Ltd. (72) Inventor Satoshi Otsu             Hitachi, 3-10-3 Bentencho, Hitachi City, Ibaraki Prefecture             Kyowa Engineering Co., Ltd. (72) Inventor Kohei Ito             Hitachi, 3-10-3 Bentencho, Hitachi City, Ibaraki Prefecture             Kyowa Engineering Co., Ltd. (72) Inventor Masao Kawakami             Hitachi, 3-10-3 Bentencho, Hitachi City, Ibaraki Prefecture             Kyowa Engineering Co., Ltd. (72) Inventor Saburo Ishihira             Hitachi, 3-10-3 Bentencho, Hitachi City, Ibaraki Prefecture             Kyowa Engineering Co., Ltd. F-term (reference) 3K070 BA26                 4D004 AA50 AB07 CA02 CA22 CA36                       DA01 DA06 DA10

Claims (7)

[Claims] 1. In an incineration facility, a contact part that comes into contact with combustion gas is heated using a combustion burner to perform dioxin purification work on the contact part, and then the work environment and deposits collected from the contact part. A method for dismantling an incineration facility, characterized by performing analysis work including analysis of dioxins of, and then dismantling the incinerator. 2. The method for dismantling an incineration facility according to claim 1, further comprising a temperature confirmation work for confirming the gas temperature of the combustion gas and the temperature of the contact portion. 3. The method of dismantling an incineration facility according to claim 1 or 2, wherein the work of removing adhering substances is carried out after the work of cleaning dioxins. 4. The dismantling of an incineration facility according to any one of claims 1 to 3, wherein a combustion cylinder is attached to a part of a contact portion of the incineration facility to introduce combustion gas to carry out dioxin purification work. Working method. 5. The method for dismantling an incineration facility according to claim 4, wherein the combustion cylinder is provided with an introduction pipe having an outlet in substantially the same direction as the combustion gas flow direction. 6. The incineration facility part reduces the level of the dismantling work management area by performing dioxin purification work on the contact part that comes into contact with the combustion gas, and thereafter the dismantling work specified in the level of the dismantling work management area. A method for dismantling an incineration facility, which is characterized by carrying out. 7. The method for disassembling work of an incineration facility according to claim 6, wherein the dioxin purification work is performed by heating each of the contact portions of the chimney, the dust collector, the flue and the incinerator with combustion gas individually. .