JP2000044960A - Plant for treating waste product, etc., equipped with exhaust gas combustion apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: Not to cause the generation of an exhaust gas containing a combustible component such as tar and water to allow the tar to adhere to the inner wall of a flue and to the filter cloth of a filter bag apparatus to bring about its functional reduction when the exhaust gas is discharged after the chloride formation and the carbonization treatment by heating a harmful component-containing substance to be treated and a treating agent in a heat treatment oven. SOLUTION: The plant for treating waste products, etc., comprises a decomposition reaction step for heating a substance to be treated and a treating agent in a heat treatment oven to decompose and separate a harmful component from the substance to be treated and at the same time rendering an exhaust gas and the substance to be treated harmless by the formation of harmless chlorides by subjecting the added treating agent and the harmful component to contact reaction; a volume reduction step for obtaining a volume-reduced residue by heating the substance to be treated which has been rendered harmless in the decomposition reaction step in a heating oven; and, as the basic means, the exhaust gases evolved in the decomposition reaction step and the volume reduction step being introduced into an exhaust gas combustion apparatus 41 by respective conduits 40a and 40b and being burned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment facility for treating an object to be treated such as waste by performing thermal treatment such as thermal decomposition, and more particularly to a treatment facility in which an object to be treated is heated using a heat treatment furnace. The present invention relates to a treatment facility provided with a combustion device for purifying exhaust gas generated in a facility.

[0002]

2. Description of the Related Art General waste such as municipal waste, industrial waste, shredder dust, vinyl chloride and other wastes contain a large amount of halogen substances (chlorine, bromine, iodine, fluorine, astatine), especially chlorine components. If heat treatment such as incineration is performed, chlorine-based gas (hydrogen chloride,
There is a problem that a large amount of (chlorine) is generated, and the exhaust gas containing the chlorine-based gas corrodes metal members of the treatment facility or generates highly toxic dioxins, thereby polluting the environment.

[0003] Techniques for solving these problems have been developed. For example, an alkaline substance (slaked lime powder) is sprayed into an incinerator for exhaust gas treatment, and chlorine-based gas in the exhaust gas generated by incineration is removed. A method of detoxifying exhaust gas by generating a harmless chloride by contact reaction, and a method of detoxifying exhaust gas by using the above alkali substance and a bag filter device in combination are being studied.

However, chlorine-based gas components adhere to and adsorb to dioxins such as slaked lime powder used in a bag filter device for treating exhaust gas, fly ash in the exhaust gas, and incineration residues such as incinerated ash. Is known to be generated.

[0005] Further, in the case of incineration of treated materials such as waste tires and wastes containing sulfides such as styrofoam, since the waste rubber contains about 5 to 10% by weight of a sulfide component. Since a large amount of sulfur oxide-based gas (SO _X gas) is generated with the combustion, it is necessary to treat these sulfur oxide-based gases.

As a method for removing such harmful components, a calcium-based alkaline substance such as lime (CaC
O ₃ ), slaked lime (Ca (OH) ₂ ), etc. for incineration, alkali substance spraying in an incinerator for treatment, or loading of these substances into a filter to pass harmful gases A method for removing harmful components by using
-93864, JP-B-2-10341, JP-A-1-296007, JP-A-59-12733.
No., etc.

In these prior arts, a chlorine-based gas is generated from an object to be processed, and the chlorine-based gas is removed by a bag filter, a high-temperature combustion, and an ash-melting means in a post-process to prevent the generation of dioxins. That is the purpose.

Further, the waste is heat-treated by a low-temperature carbonization method in a rotary processing furnace to convert it into a low-temperature carbonized gas and a pyrolysis residue, which is burned in a high-temperature combustion furnace to produce a molten liquid slag, There has also been proposed a processing method of reducing the volume of an object to be processed by processing, and processing and discharging the generated gas by a boiler, a removal filter, and a gas purifying device (Japanese Patent Application Laid-Open No. H08-208,878).
510789).

[0009] As another method, when an object to be treated is heat-treated in a heat treatment furnace, an appropriate amount of an alkaline additive which easily reacts with the chlorine component is mixed and heat-treated to fix the chlorine component in the treated ash. A method has also been proposed in which harmless exhaust gas is obtained by converting the treated ash to a chlorine component by washing with water or the like (JP-A-9-155326).

Further, methods for melting and vitrifying incinerated ash are disclosed in JP-A-9-236242 and JP-A-9-236239 in order to further reduce the volume and harmlessness of wastes and the like. I have.

[0011]

When an object to be treated is thermally decomposed in a heat treatment furnace by dry distillation or the like, exhaust gas containing water is generated in the drying step. Further, in the carbonization step, exhaust gas containing combustible components such as tar components is generated. Further, it is known that a large amount of tar is generated when a plastic-based material is heated. Attempts have been made to cool and collect a part of these tar components and reuse them by oiling.

However, if a large-scale treatment facility or a special facility installed for the purpose of collecting oil can be used to industrially collect tar as oil, a normal treatment facility with a small treatment amount, for example, It is extremely difficult to add a facility for collecting tar as oil in a heat treatment furnace having a throughput of 5 tons / day.

On the other hand, when the exhaust gas containing the tar component is discharged as it is, the tar component adheres to the inner wall of the flue or to the filter cloth in the bag filter device, thereby deteriorating the function of the bag filter device and reducing the filter cloth. Undesirable results such as shortening of the service life may be caused.

As a countermeasure, a means for burning the exhaust gas to decompose the tar component and then discharging the exhaust gas can be considered. However, if the method for burning the exhaust gas is not carefully considered, there is a possibility that dioxins may be newly generated during combustion.

It has been conventionally known to use an alkaline substance as a substance which generates a harmless chloride by reacting with a harmful component generated from an object to be treated by incineration. Is not stable and produces harmful components such as hydrogen chloride, which leads to environmental degradation such as the production of dioxins, which may create a very dangerous state for the future of humankind. .

At present, a method of removing exhaust gas containing hydrogen chloride or the like in a post-process using a bag filter device or the like is generally performed. However, there is no mention of the treatment of the additive used in the bag filter device.

Further, the fact that hydrogen chloride is contained in the exhaust gas means that the residue after incineration also contains harmful components such as hydrogen chloride. Although little attention has been paid to the harmfulness of this residue in the past, it is implicitly known that the residue is a harmful substance, and these incinerated ash can be reduced in volume by vitrification or other means. The harm is evident from the fact that the components are being contained.

Therefore, no attempt has been made at the same time to achieve the detoxification of exhaust gas from heat treatment furnaces such as incinerators and the detoxification of residues after incineration at the same time.

Therefore, according to the present invention, when decomposing an object to be treated such as waste, a harmful component such as chlorine-based gas is decomposed and precipitated from the object to be treated in a treatment furnace, and the harmful component thus deposited is separated from an alkali substance. By reliably contacting and reacting with such a treating agent to form harmless chloride, detoxification of exhaust gas and residue is realized, and this detoxified residue is carbonized in the same or another processing furnace. The purpose of the present invention is to obtain a technical means that can be reused by reducing the volume.

Another object of the present invention is to introduce flue gas containing flammable components such as moisture and tar components generated in the drying step, the decomposition reaction step, and other steps into a combustion device through separate conduits for combustion. In this way, stable combustion efficiency can be obtained even in a small-sized combustion facility, and a waste treatment facility that can effectively remove tar components and chlorine-based gas that generates dioxins is provided. Is to do.

[0021]

The inventor of the present application has obtained the following findings as a result of various experimental studies.

(1) Focusing on the fact that detoxified exhaust gas containing no chlorine-based gas is not likely to generate new harmful substances even when burned, and this exhaust gas is burned by a combustion device. Inflammable gas components such as tar components can be decomposed and removed, and no new dioxins are generated.

(2) Since the exhaust gas generated in the decomposition reaction step in which the object to be treated is thermally decomposed in a heat treatment furnace contains a large amount of water, the introduction of the exhaust gas into the combustion furnace requires a volume reduction step. That a stable exhaust gas combustion effect can be obtained by introducing it through a separate conduit from that of the exhaust gas generated in the above.

(3) Petroleum (kerosene), LPG = propane (liquefied petroleum gas: CH ₃ C)
Natural gas (LN), which has less hydrocarbon components than H ₂ CH ₃ )
It is preferable to use G) because there is no generation of dioxins.

(4) When a calcium-based treating agent such as slaked lime is added to an object to be treated and subjected to heat treatment, the treating agent comes into contact with a chlorine-based gas in exhaust gas to produce harmless chloride. Therefore, a certain effect can be expected as compared with the case where the treating agent is not used.

As a result of various studies with the expectation of further expansion of the above effects, alkali metals and alkali metal compounds which react with harmful components decomposed and precipitated from the object to be heated to produce harmless chlorides as alkali substances , Alkaline earth metals, and alkaline earth metal compounds,
If at least one kind is selected, or if a mixture of two or more kinds, in particular, a sodium or potassium-based alkali metal compound is used as a treating agent, a harmless chloride can be effectively produced and a harmful component can be removed. I found it.

The present invention has been made based on these findings, and a specific means for solving the above problems is to heat an object to be treated and a treating agent comprising an added alkali substance in a heat treatment furnace, and Decomposition reaction process in which harmful components are decomposed and precipitated from the processed material, and the added processing agent and harmful components are contact-reacted to form harmless chlorides, thereby detoxifying the exhaust gas and detoxifying the processing target. And a volume reduction step of heating the object detoxified in the decomposition reaction step in a heating furnace to obtain a reduced volume residue, wherein the exhaust gas generated in the decomposition reaction step and the volume reduction step Basic means is provided with an exhaust gas combustion device for introducing the generated exhaust gas into the exhaust gas combustion device through separate conduits and burning the exhaust gas.

The decomposition reaction step and the volume reduction step are performed in different heat treatment furnaces. In addition, natural gas is used as a fuel for the exhaust gas combustion device, and the exhaust gas burned by the exhaust gas combustion device is sent to a bag filter device after cooling to be cleaned.

The treating agent for an alkali substance is an alkali metal, an alkali metal compound, an alkaline earth metal, or an alkaline earth metal compound which reacts with a harmful component decomposed and precipitated from an object to be treated by heating to form a harmless chloride. , At least one kind is selected from the substances contained in, or a mixture of two or more kinds.

The alkali metal compound is selected from sodium hydrogencarbonate, sodium carbonate, sodium sesquicarbonate, natural soda, potassium carbonate, potassium hydrogencarbonate, sodium potassium carbonate, sodium hydroxide, potassium hydroxide, or a mixture of plural kinds thereof. Consists of

The treating agent for an alkaline substance is brought into contact with a harmful chlorine gas in a powder form. The treatment agent used in the heat treatment furnace is added in an amount of 2 to 10 times the amount of chlorine contained in the object, or 5 to 30% by weight of the object.

The heat treatment temperature in the decomposition reaction step is a temperature at which harmful components are decomposed and precipitated from the material to be treated. Specifically, 250 ° C. at which a chlorine-based gas is decomposed and precipitated from the object to be treated
~ 350 ° C.

The heat treatment temperature in the volume reduction step is a temperature at which the material to be treated is carbonized or incinerated. Specifically, the temperature is 350 ° C. to 700 ° C., which is the temperature at which the object is carbonized, or 1000 ° C. or more, which is the temperature at which the object is incinerated.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. The present invention heats a treatment agent and a treatment agent comprising an added alkaline substance in a heat treatment furnace to decompose and precipitate harmful components from the treatment object, and causes a contact reaction between the added treatment agent and the harmful component. A decomposition reaction step in which harmless chlorides are formed to detoxify the exhaust gas and detoxify the object, and the object detoxified in the decomposition reaction step is heated in a heating furnace to reduce the volume. Exhaust gas generated in the decomposition reaction step and exhaust gas generated in the volume reduction step are introduced into the exhaust gas combustion device through separate conduits and burned. It is characterized by:

FIG. 1 is a conceptual view of an embodiment in which two heat treatment furnaces are installed, and FIG. 2 is a sectional view of a cylindrical body.

In FIG. 1, reference numeral 10 denotes a first heat treatment furnace for performing a decomposition reaction step, and reference numeral 20 denotes a second heat treatment furnace for performing a volume reduction step. The first heat treatment furnace 10 includes a rotatable cylindrical body 11 having a blade S (see FIG. 2) for moving an object to be processed while being stirred, and a gas duct formed on the outer periphery of the cylindrical body 11 to form a hot gas. A heating tube 12 for heating the cylindrical body 11 by introducing the same, a supply port 13 provided at one end of the cylindrical body 11 to supply the object to be processed into the cylindrical body 11, and the other end of the cylindrical body 11 The cylindrical body 11 is rotatably driven by a rotation driving means 15. The rotation driving means 15 includes a driving motor 15a, a driving gear 15b, and a driven gear 15c provided on the cylindrical body 11.
Consists of

Reference numeral 16 denotes a supply side duct surrounding the supply port 13 side, and 17 denotes a discharge side duct surrounding the discharge port 14 side so that an additional treatment agent Sm can be sprayed in as required. Reference numeral 18 denotes a heating coil (induction heating or resistor), which is provided on the outer periphery of the cylindrical body 11 on both sides of the heating cylinder 12 in a non-contact and close proximity to the cylindrical body 11, and constitutes a heating means together with the heating cylinder 12. .

In the drawing, reference numeral 19 denotes a sensor mounting device, and P denotes a dynamic seal (mechanical seal).

The second heat treatment furnace 20 has the same basic configuration as the first heat treatment furnace 10 described above. Therefore, in the same or corresponding parts, the first digit after 20 is set to the same number (for example, 21 is a cylindrical body, 22 is a heating cylinder, 29 is a sensor mounting device), and description thereof will be omitted.

Reference numeral 30 denotes a hopper, which mixes an object to be treated and a treating agent composed of an alkaline substance and puts the mixture into the hopper 30, and the object to be treated is passed through an opening / closing valve (opening / closing door) 31 of the cylinder 11. It is supplied from the supply port 13 into the cylindrical body 11. The material to be treated may be any of solid matter such as general waste and industrial waste, ash, and sludge.

The hopper 30 has a crushing function and a mixing function of the processing agent, and may mix the processing agent while crushing the solid material. May be mixed and charged.

The cylindrical body 11 of the first heat treatment furnace 10 and the cylindrical body 21 of the second heat treatment furnace 20 are arranged vertically, and the discharge duct 17 of the cylindrical body 11 and the supply of the cylindrical body 21 are provided. The opening 23 is communicated with an opening / closing valve (opening / closing door) 32, and the discharge side duct 27 of the cylindrical body 21 of the second heat treatment furnace 20 is connected to a melting tank 34 via an opening / closing valve (opening / closing door) 33. And discharges the carbide or treated ash after the heat treatment.

Numeral 35 denotes a combustion device, which burns LNG from the LNG tank 36 to generate hot gas when burning LNG, for example. This hot gas is supplied into a heating cylinder 22 provided on the outer periphery of the cylindrical body 21 and heats the cylindrical body 21, and then is sent into the heating cylinder 12 of the cylindrical body 11 through the communication pipe 37, and Is heated and then sent out to the drying means 39 via the discharge pipe 38 to be used as heat of the drying means.

Reference numeral 41 denotes a flue gas combustion device, into which flue gas is fed from the discharge duct 17 of the first heat treatment furnace 10 via a conduit 40a. From the supply duct 26 to the conduit 40b
The exhaust gases are separately fed via

45 is a dehydrating means, which separates the aqueous solution in the dissolving tank 34 into solid and liquid, and after drying the solid by the drying means 39, discharges it to the carbide hopper 46;
After neutralization with a neutralizing agent or the like in step 7, it is returned to the dissolution tank 34 for reuse.

The exhaust gas after the solid matter is dried by the drying means 39 is passed through the exhaust gas combustion device 41 via a conduit 40c.
Sent to.

As described above, the exhaust gas generated in the decomposition reaction step, the exhaust gas generated in the volume reduction step, and the exhaust gas generated and used in other steps have different properties depending on the temperature and contained substances. To the conduits 40a, 40
One of the features of the present embodiment is that the b and 40c separately introduce the gas into the exhaust gas combustion device 41 and burn it. The gas burned by the exhaust gas combustion device 41 is sent to a bag filter device 43 in the next step.

Next, a series of processing methods will be described.
First, LNG is burned by the combustion device 35 to generate hot gas, which is supplied to the heating cylinders 22 and 12. If necessary, AC power is supplied to the heating coils 18 and 28 so that the cylindrical body 2
Heat 1,11. Next, (or at the same time) a mixture of the object to be treated containing the harmful component and the treatment agent, or the mixture is supplied from the hopper 30 into the cylindrical body 11 of the first heat treatment furnace 10 while mixing.

In the heat treatment in the first heat treatment furnace 10, the temperature and time at which the harmful component is precipitated from the object to be treated are investigated in advance, the properties of the object to be treated are grasped, and the result of the examination is sufficiently obtained. The treatment is performed at a temperature (200 ° C. to 350 ° C.) and time that can be covered.

The time and temperature are related to the state of the heating furnace (conditions depending on the furnace such as the size and heating means), the amount of treatment, the treatment time, the treatment temperature, and the like. Must be performed sufficiently, and data must be collected and stored.

The heating in the first heat treatment furnace is not "combustion and incineration" but "steaming and pyrolysis", and the chlorine-based gas and the like are decomposed and precipitated from the object to be treated, and the treating agent is treated. And react with. By this reaction, as described later, the detoxification of the decomposition gas and the residue is simultaneously performed.

The detoxified object to be treated is the duct 1
7. It is sent to the supply port 23 of the cylindrical body 21 of the second heat treatment furnace 20 through the opening / closing valve 32, and the temperature at which the material to be treated is carbonized here (carbonization of paper starts at about 350 ° C).
Heat to 350 ° C to 700 ° C and carbonize or 800 ° C
The above heating is performed to reduce the volume by incineration. Since there is no decomposed gas containing harmful components such as HCl and dioxins in the second heat treatment furnace 20 in this volume reduction step,
The carbonized or incinerated object does not absorb it.

The reduced volume of the object to be processed and the processing agent after the reaction are discharged into a melting tank 34 via a duct 27 and an opening / closing valve 33. In the dissolving tank 34, the reduced volume of the object to be treated, the treated agent after the reaction, and the like are dissolved in water, and this is separated into a solid and a liquid by a dehydrating means 45, and the solid is dried. After drying at 39, take out from the carbide hopper 46,
On the other hand, the liquid is recovered by the water treatment means 47, and the treated agent is recovered, injected with a neutralizing agent or the like, treated, and then returned to the dissolution tank 43 for reuse.

Although the harmful chlorine gas is not basically contained in the exhaust gas after the reaction, the properties of the object to be treated vary widely. Depending on the cause, it may occur that the chlorine component cannot be completely removed. Therefore, the bag component 43 is used for complete cleaning.

As a pre-process to be taken into the bag filter device 43, the exhaust gas generated in the decomposition reaction process and the exhaust gas generated in the volume reduction process are introduced into the exhaust gas combustion device 41 through separate conduits 40a and 40b, and further dried. The exhaust gas after drying the solid matter at 39 is also sent to the exhaust gas combustion device 41 via the conduit 40c and burned at the same time.

The exhaust gas combustion device 41 burns and removes twistable components such as water and tar contained in the gas.
The obtained gas is cooled to below the endurance temperature (about 150 ° C.) of the bag filter device 43 together with the cooling air (normal temperature or cooled air) sent from the air supply means 42 and then introduced into the bag filter device 43.

The bag filter device 43 may be a conventionally known bag filter device. In this bag filter device 43, a powder of a treating agent (eg, sodium carbonate NaHCO ₃ ) is sprayed into the exhaust gas to cause a contact reaction, and the filter cloth is exhausted by the exhaust gas. The exhaust gas is cleaned by passing through. The used processing agent is collected, mixed into the object to be processed in the initial process, and put into the hopper 30 to be reused. Exhaust gas from the bag filter device 43 is discharged from the chimney 44.

FIG. 3 is a conceptual diagram for explaining the combustion operation of the exhaust gas combustion device 41.
A burner 50 is provided at one end of the fuel cell 1, and natural gas (LNG) 51 is supplied as fuel.

The exhaust gas combustion device 41 is provided with three gas supply ports. 52 is a supply port of exhaust gas generated in the decomposition reaction step, 53 is a supply port of exhaust gas generated in the volume reduction step,
Reference numeral 54 denotes a supply port for exhaust gas generated at other locations (in this example, the drying unit 39). Reference numeral 55 denotes an exhaust port for discharging harmless gas after combustion.

The conduits 40a, 40b, and 40c are separately connected to the gas supply ports 52, 53, and 54, respectively, and the respective exhaust gases are simultaneously burned by the thermal power of the burner 50.

The natural gas (LNG) used as fuel is
Compared with petroleum (kerosene) and LPG (propane gas), the hydrocarbon component is small. By using this natural gas, there is no fear that dioxins are generated by combustion.

The temperature control means of the first and second heat treatment furnaces is performed as follows. In the first heat treatment furnace 10, a valve (open / close valve or three-way valve) is provided in a communication pipe 37 with the heating cylinder 22 of the second heat treatment furnace 20. Are provided, and the flow rate of the hot gas is controlled by means for selecting the number of used by the valve opening / closing control.
In the case of induction heating, the temperature is controlled by means for controlling the alternating current supplied to the heater or in the case of induction heating. These controls are performed by a temperature detection sensor provided in the sensor mounting device 19,
Alternatively, the detection is performed by detecting the temperature or the gas concentration in the cylindrical body 11 with a sensor for detecting a gas component. Or HC in duct 17
The gas concentration such as 1 is detected by a gas concentration meter 48 and automatically or manually controlled. At this time, when the gas concentration in the duct 17 is higher than a predetermined value, the additional treatment agent Sm is administered into the duct 17 by spraying or the like, and is reacted with the remaining gas to make it harmless.

The temperature control means of the second heat treatment furnace 20 is substantially the same as that described above.
The control of the NG combustion means becomes main, and the electric heating means assists. These controls are also performed by the HC in the ducts 26 and 27.
Control is performed by reflecting detection signals from gas concentration meters 49 and 50 for measuring the l concentration and a temperature sensor or a gas component sensor in the sensor mounting device 29.

The heating of the drying means 39 utilizes the hot gas after heating the first and second heat treatment furnaces 10 and 20 so as to effectively utilize the heat energy.

In the embodiment shown in FIG. 1, as means for stirring and moving the objects to be processed in the first and second heat treatment furnaces 10 and 20, as shown in FIG. It is a case where the blade S is provided to move the cylindrical body itself by rotating, but it is not always necessary to rotate the cylindrical body, the cylindrical body is fixed, and a long screw body is provided in the internal axial direction. Alternatively, the screw body may be driven to rotate from the outside.

Although the heating means for heating the cylindrical body has been described as applying both heating by a hot gas and heating by a heating coil, heating by a heating coil is not always necessary.

As described above, according to the present invention, the harmful component is decomposed and precipitated from the object to be treated in the heat treatment furnace, and at the same time, the harmful component is caused to react with the treating agent. And the exhaust gas generated in the decomposition reaction process,
Basically, the exhaust gas generated in the volume reduction step and the exhaust gas generated in other steps are introduced into an exhaust gas combustion device through separate conduits and burned.

When an object to be treated containing a halogen substance and a treating agent of an alkali metal compound are mixed and heated in a heat treatment furnace, even if a harmful chlorine gas is generated, the chlorine gas is added. The following experimental investigation revealed that the reaction with the treating agent (dechlorinating agent) produces harmless chlorides, and the detoxification of the decomposed gas and the detoxification of the residue can be performed at the same time.

In the experiment, the sample was placed in a sealed container equipped with an exhaust pipe and having an open / close door, heated in an electric furnace, and heated from 250 ° C. to 6 ° C.
Hold at each temperature for 5 minutes at intervals of 50 ° C until 00 ° C, open the exhaust pipe at the time of temperature rise and keep, and open hydrogen chloride gas (HCl).
The concentration (ppm) was measured.

The gas concentration was measured with a detector tube specified in JIS-K0804.

Table 1 shows the measurement results. The hydrogen chloride gas concentration is a measured value in ten experiments, and Examples 1 to 5 show the highest values, and Comparative Examples 1 to 3 show the lowest values.

Note that "ND" represents "not detected",
It shows that none was detected in 10 experiments.

In the experiment, first, a preliminary test was conducted using only 4 g of polyvinylidene chloride containing a large amount of a chlorine component. The results are shown in Comparative Example 1 of Table 1.

Next, an experiment was conducted by adding 20 g each of slaked lime and calcium carbonate powder conventionally known as dechlorinating agents. The results are shown in Comparative Examples 2 and 3.

Next, polyvinylidene chloride and vinyl chloride, which generate a large amount of hydrogen chloride when heated, were selected as the objects to be treated. The material was selected and added for the experiment.

In Examples 1 and 2, 20 g of sodium bicarbonate powder was added to polyvinylidene chloride 4 to be treated.
g and 4 g of vinyl chloride, Examples 3 to 5 were applied to 4 g of polyvinylidene chloride of the same material.
In each of the examples, an experiment was carried out by mixing an object to be treated and a dechlorinating agent when 10 g of potassium hydrogen carbonate, 20 g of sodium hydroxide and 20 g of potassium hydroxide were added.
Table 1 shows the results.

[0077]

[Table 1]

From the experimental results shown in Table 1, the following is considered.

First, when polyvinylidene chloride containing a large amount of a chlorine component is to be treated, in Comparative Example 1 in which no dechlorinating agent is added, a large amount of hydrogen chloride gas is generated over each temperature due to the heat treatment. In Comparative Example 2 in which slaked lime, which is a conventional dechlorinating agent, was added to this object, and in Comparative Example 3 in which calcium carbonate was added, although the generation of hydrogen chloride gas was considerably suppressed as compared with Comparative Example 1, Not enough.

In Comparative Examples 2 and 3, it is presumed that the reaction between the reactant and hydrogen chloride generated at around 300 to 350 ° C., which is a temperature range in which hydrogen chloride is likely to be generated, is not sufficiently performed.

On the other hand, in the case of the alkali metal compound, a very small amount (1 p
pm, 2 ppm), but no other gas was detected over the entire temperature range, and very good results were obtained.

In addition, when sodium hydrogencarbonate was added to the material to be treated using vinyl chloride, as shown in Example 2, the production of hydrogen chloride was completely suppressed in any temperature range. I have.

When applied to actual waste, it is normal that the generation of chlorine-based gas does not occur as much as in the experiment, so that the effect is not as high as in Examples 1 to 5. If it is, it is practical enough.

According to the above experimental investigation, in the case of dechlorination treatment, an alkali substance which reacts with a chlorine-based gas to produce harmless chloride, particularly an alkali metal compound, is added to the treatment, whereby the detoxification treatment is performed. It was confirmed that it was possible.

Although similar results were obtained when the heating temperature was 600 ° C. or higher, the heating conditions may be determined in consideration of the type of equipment, time, amount of processing, and the like.

The reason that the harmful hydrogen chloride is replaced with a harmless chloride is apparent from the following reaction.

(1) In the case of sodium hydrogen carbonate (NaHCO ₃ ) + (HCl) → (NaCl) + (H
_{2 O) + (CO 2)} (2) For potassium hydrogen carbonate _{(KHCO 3) + (HCl)} → (KCl) + (H 2 O) +
(CO ₂₎ (3) the case of sodium hydroxide (NaOH) + (HCl) → (NaCl) + (H 2 O) (4) if the potassium hydroxide (KOH) + (HCl) → (KCl) + ( H ₂ O) In particular, the effect in the case of bicarbonate is remarkable.
First, CO ₂ is separated at a temperature lower than the temperature (250 ° C. or higher) at which hydrogen chloride (HCl) is decomposed and precipitated, so that an atmosphere state in which the reaction between the remaining NaOH and KOH and the generated HCl can be performed smoothly. It is considered that there is.

That is, the reaction state is sodium hydrogen carbonate (NaHCO ₃ ) → (NaOH) + (CO ₂ ) (NaOH) + (HCl) → (NaCl) + (H
₂ O) Potassium hydrogen carbonate (KHCO ₃ ) → (KOH) + (CO ₂ ) (KOH) + (HCl) → (KCl) + (H
₂ O) next to, NaOH, those in which the KOH and HCl newly generates a harmless chlorides react rapidly (NaCl, KCl).

On the other hand, in the case of calcium carbonate (CaCO ₃ ) and slaked lime (Ca (OH) ₂ ) in Comparative Examples 2 and 3,
Similarly, harmless chloride (CaCl) is produced but Ca
It seems that the reaction with is not smooth.

NaCl, KCl produced as described above
Is a harmless chloride.
There are the following sodium-based and potassium-based substances that generate Cl and KCl, and similar effects can be obtained.

Sodium carbonate Potassium carbonate Sodium potassium carbonate Sodium carbonate hydrate Sodium sesquicarbonate Natural soda Next, the obtained residue was analyzed, and chlorine-based substances after dechlorination were confirmed. No system gas components were detected, and harmless chlorides sodium chloride and potassium chloride were detected. Further, the residue was stirred for 10 minutes and washed with water, so that sodium chloride and potassium chloride were dissolved in water and a carbide remained, but no harmful chlorine-based gas component was detected in the carbide.

Therefore, the harmful chlorine components are sodium chloride (NaCl) and potassium chloride (K
Cl), water (H ₂ O), and gas (CO ₂ ), and do not generate hydrogen chloride, which causes the generation of dioxins.

As a treating agent used in such a dechlorination treatment, an alkali metal compound was found to be most preferable. That is, (1) a simple substance of an alkali metal compound or a mixture of plural kinds thereof. (2) The alkali metal compound is a hydroxide or a carbonate substance. (3) A hydroxide or carbonate is a sodium-based or potassium-based substance. ) The treating agent is selected from sodium bicarbonate, sodium carbonate, sodium sesquicarbonate, natural soda, potassium carbonate, potassium bicarbonate, sodium potassium carbonate, sodium hydroxide, potassium hydroxide, and a mixture of multiple types Also turned out.

Another alkaline substance, ie, an alkali metal,
Alkaline earth metals and alkaline earth metal compounds cannot be expected to be as effective as alkali metal compounds, but they can be practically used as long as the content of the object to be treated and the form of application are determined and used. .

Therefore, the harmful components are replaced with harmless chlorides (NaCl, KCl) by the contact reaction between the harmful chlorine-based gas in the decomposition gas generated from the object to be treated and the added treating agent. A harmful component (chlorine-based gas) can be separated from the decomposed gas, and a harmless decomposed gas can be obtained.

Accordingly, even if the exhaust gas generated in the drying, reaction step and volume reduction (dry distillation) step is burned, no problem is caused thereby.

On the other hand, the harmless chloride which becomes a part of the residue,
It can be effectively removed by washing with a solution such as water,
Moreover, after cleaning, reusable metals, carbides, etc. remain and contain no harmful chlorine-based gas components, so that they can be reused.

Further, before and after the washing treatment, each substance can be separated by an arbitrary separating means, and the separated substance can be dried and solidified to be used effectively as fuel or the like.

Although the treatment liquid after washing contains harmless chlorides, it contains almost no harmful substances, and can be subjected to wastewater treatment as required and discharged into rivers or the ocean.

[0100]

As described above in detail, according to the present invention, an object to be treated is heat-treated in a heat treatment furnace together with a treating agent, and harmful components such as chlorine components contained in the object to be treated (particularly chlorine And a decomposition reaction step of detoxifying exhaust gas and detoxifying an object to be treated by contacting the added treating agent with harmful components to form harmless salts. A volume reduction step of heating a treatment object made harmless in the decomposition reaction step with a heating furnace to obtain a reduced volume residue, and an exhaust gas generated in the decomposition reaction step and an exhaust gas generated in the volume reduction step. The exhaust gas generated in the other steps and the exhaust gas generated and used in the other processes are introduced into the exhaust gas combustion device through separate conduits and burned, so that the following effects are obtained.

(1) In the decomposition reaction step of decomposing and depositing harmful components (such as chlorine-based gas) contained in the object,
By heating both the material to be treated and the treating agent added, the contact reaction between the chlorine-based gas decomposed and deposited and the treating agent is quickly and reliably performed, and harmless chloride is generated and generated. Since the gas and the residue are made harmless and no chlorine-based gas remains in the exhaust gas, generation of dioxins can be prevented.
In addition, by introducing exhaust gas with different properties (temperature, contained substances) generated in the decomposition reaction step, volume reduction step, and other steps into the exhaust gas combustion device through separate conduits and burning, stable combustion is achieved. Harmless gas is obtained.

(2) By using natural gas (LNG) having a low hydrocarbon component as fuel for the exhaust gas combustion apparatus, tar can be efficiently removed and there is no fear that dioxins will be generated by combustion. The present invention can be applied to a small heat treatment furnace having a small processing amount.

(3) In the volume reduction step of heating and reducing the volume of the object to be treated from which chlorine-based gas has been removed, dioxins generated due to chlorine-based harmful substances do not exist in the residue. In addition, dioxins do not adsorb and mix into the residue (carbide and ash), so that the residue can be made harmless, and the carbide can be extracted from the residue and reused as a secondary fuel.

(4) In the decomposition reaction step of decomposing and depositing harmful components, it is most effective to use an alkali metal compound as a treating agent. It is possible.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a waste treatment facility according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a cylindrical body.

FIG. 3 is a conceptual diagram for explaining a combustion operation by an exhaust gas combustion device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... 1st heat processing furnace 11, 21 ... Cylindrical body 12, 22 ... Heating cylinder 13, 23 ... Supply port 14, 24 ... Discharge port 15, 25 ... Supply side duct 16, 26 ... Discharge side duct 28 ... Fixing member DESCRIPTION OF SYMBOLS 30 ... Hopper 31 ... Combustion apparatus 32 ... Communication pipe 33 ... Discharge pipe 36 ... Dissolution tank 37 ... Dehydration means 38 ... Carbide 40 ... Exhaust gas combustion apparatus 40a, 40b, 40c ... Conduit 41 ... Cooling apparatus 42 ... Bag filter apparatus 42a ... Reaction Chemical adding means 43 ... Treatment agent 44 ... Chimney 50 ... Burner 51 ... Natural gas 52,53,54 ... Gas supply port 55 ... Exhaust port

Claims (12)

[Claims] Claims: 1. In a waste treatment facility for reducing the volume of an object to be treated by heat-treating the object to be treated such as waste in a heat treatment furnace, a treatment comprising the object to be treated and an added alkali substance. The chemicals are heated in a heat treatment furnace to decompose and deposit harmful components from the material to be treated, and the harmful components are contact-reacted with the added processing agents to form harmless chlorides, thereby making the exhaust gas harmless. A decomposition reaction step of detoxifying the object to be treated, and a volume reduction step of heating the detoxified object in the decomposition reaction step in a heating furnace to obtain a reduced volume residue. A waste treatment facility equipped with an exhaust gas combustion device, wherein exhaust gas generated in the process and exhaust gas generated in the volume reduction process are introduced into an exhaust gas combustion device through separate conduits and burned. 2. The facility for treating waste or the like provided with an exhaust gas combustion device according to claim 1, wherein the decomposition reaction step and the volume reduction step are performed in different heat treatment furnaces. 3. A waste treatment facility provided with an exhaust gas combustion device according to claim 1, wherein natural gas is used as a fuel for the exhaust gas combustion device. 4. A waste treatment facility provided with an exhaust gas combustion device according to claim 1, wherein the exhaust gas burned by the exhaust gas combustion device is cooled and then purified by a bag filter device. 5. A treatment agent for an alkaline substance, which reacts with a harmful component decomposed and precipitated from an object to be treated by heating to form a harmless chloride, an alkali metal compound, an alkaline earth metal, and an alkaline earth. The waste treatment facility provided with the exhaust gas combustion device according to claim 1, wherein at least one kind is selected from a substance contained in the metal compound, or a mixture of two or more kinds is included. 6. The alkali metal compound is selected from the group consisting of sodium hydrogencarbonate, sodium carbonate, sodium sesquicarbonate, natural soda, potassium carbonate, potassium hydrogencarbonate, sodium potassium carbonate, sodium hydroxide, and potassium hydroxide, or a plurality thereof. A waste treatment facility equipped with the exhaust gas combustion device according to claim 5, wherein 7. The treatment agent for an alkaline substance is brought into contact with a harmful chlorine gas in a powder form.
Or a waste treatment facility provided with the exhaust gas combustion device according to any one of the above items 6. 8. The treatment agent used in the heat treatment furnace is 2 to 10 times the amount of chlorine contained in the object, or 5 to 5 times the amount of chlorine contained in the object.
A waste treatment facility provided with the exhaust gas combustion device according to claim 1 or 2, wherein 30% by weight is added. 9. The heat treatment temperature in the decomposition reaction step is as follows:
A waste treatment facility equipped with an exhaust gas combustion device according to claim 1 or 2, wherein the temperature is a temperature at which harmful components are decomposed and precipitated from a treatment object. 10. The heat treatment temperature in the decomposition reaction step is from 250 ° C., at which chlorine-based gas is decomposed and precipitated from the object to be treated.
A waste treatment facility equipped with the exhaust gas combustion device according to claim 1, wherein the temperature is 350 ° C. 10. 11. The heat treatment temperature in the volume reduction step is as follows:
The waste treatment facility provided with the exhaust gas combustion device according to claim 1 or 2, wherein the temperature of the object to be treated is at a temperature at which carbonization or incineration occurs. 12. The heat treatment temperature in the volume reduction step is as follows:
The exhaust gas combustion device according to any one of claims 1, 2, or 11, wherein the temperature is 350 ° C to 700 ° C, which is a temperature at which the object is carbonized, or 1000 ° C or more, which is a temperature at which the object is incinerated. Waste treatment facilities.