JP2000015635A - Method for dechlorination of waste and method and apparatus for producing dechlorinated fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the dechlorination of waste in which organic chlorine compounds are not generated, and the amount of generated waste such as a gasification residue and combustion ash can be controlled and a method and an apparatus for producing dechlorinated fuel. SOLUTION: An apparatus is constituted from a crusher 12 for crushing waste 11 containing chlorine into particles of a prescribed size or below, a preheater 14 for preheating the crushed waste 13, a dechlorination furnace 17 for dechlorination by heating in a high concentration of steam introduced from a steam introduction means 16, a separator 21 for separating pyrolysate 18 into exhaust gas 19 and dechlorinated solids 20, a crusher 22 for crushing the solids 20 into particles of a prescribed size or below, and a water-washing tank 24 which washes the crushed dechlorinated solids 23 with water and removes inorganic salts. The waste 11 is dechlorinated, excess water of slurry after being washed with water in the tank 24 is removed as drainage 25 in order to obtain dechlorinated slurry fuel 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, NaCl, MgCl
Dioxin is used in the treatment of general refuse discharged from homes containing inorganic chlorine compounds such as ₂ ), plastic mixtures containing plastics containing chlorine such as vinyl chloride, and plastics containing chlorine and car shredder dust containing inorganic components. A method for dechlorination of waste that does not generate harmful organic chlorine compounds such as chemicals and can further reduce the amount of waste generated such as gasification residues and combustion ash, and dechlorination that makes effective use of processed products The present invention relates to a method and an apparatus for producing a fuel.

[0002]

2. Description of the Related Art In recent years, a large amount of plastic mixtures containing chlorine-containing plastics such as polyvinyl chloride and polyvinylidene chloride and wastes containing inorganic components have been discharged, and the amount of wastes has been increasing steadily. ing.
At present, most of such waste is incinerated or landfilled.

In the case of incineration, harmful substances such as hydrogen chloride and dioxins generated during incineration may be released to the atmosphere as they are. In addition, in the case of landfill disposal, resources are lost because the effective components in the waste are not used. Thus, it has been proposed to thermally decompose these wastes to recover the effective components therein.

However, a large amount of chlorine compounds such as hydrogen chloride and chlorine gas is generated by the thermal decomposition, gasification or combustion of plastics containing chlorine in wastes, which not only causes great pollution, but also causes thermal pollution. Causes decomposition, gasification or combustion furnace corrosion. Therefore, in order to remove chlorine compounds by pretreating these wastes, a method has been proposed in which thermal decomposition is performed in a decomposition tank by indirect heating using a heating medium or a heater.

[0005] In this method, it is difficult to uniformly heat the solid inside the decomposition furnace. In particular, in the case of thermoplastics, the parts softened and melted by local heating are fused together to form a lump,
Undecomposed hydrogen chloride is left in the molten plastic and cannot be completely removed. Further, by adding an alkali metal compound such as Ca, Na and K to these wastes and subjecting them to pyrolysis, gasification or combustion, a chlorine compound (CaCl 2) ₂ , NaCl, KCl, etc.).

[0006]

Embedded image Ca (OH) ₂ + 2HCl → CaCl ₂ + 2H ₂ O (1) CaCO ₃ + 2HCl → CaCl ₂ + H ₂ O + CO ₂ (2) NaOH + HCl → NaCl + H ₂ O ... (3) KOH + HCl → KCl + H ₂ O ... (4)

However, in order to react the entire amount of hydrogen chloride HCl generated from the waste with the alkali metal to decompose it as a chlorine compound, in consideration of the reaction rate, conventionally, about four times or more equivalent amount of the alkali metal is used. Was added. As a result, a large amount of residue was discharged due to the addition of excess alkali metals, which was a problem.

Further, after pre-treating waste containing a metal such as car shredder dust by this method, the residue containing a by-product chlorine compound or metal is again treated in a melting furnace or the like to recover the metal. There is also a problem that these chlorine compounds are in a molten state at a high temperature of about 750 ° C. or more, which scatter as mist and cause corrosion in contact with metal. In particular, in a method of burning waste containing a large amount of chlorine as it is and adding an alkali metal compound to the waste, the amount of chlorine compound produced as a by-product increases, and the problem of corrosion due to the melt increases.

Further, since a trace amount of heavy metal is contained in plastic as a plasticizer, a stabilizer or a paint, there is a problem in disposing of these combustion residues as they are.

[0010]

According to the first aspect of the present invention, which solves the above-mentioned problems, a dechlorination step of thermally decomposing a waste containing chlorine and performing a dechlorination treatment is provided. Separation step of separating solids and pyrolysis gas, and pulverization step of pulverizing and separating the separated dechlorinated solids,
A water washing step of washing the finely divided dechlorinated solid with water to remove inorganic salts.

[0011] The invention of claim 2 is characterized in that, in the first aspect of the present invention, a pulverizing step is provided before the dechlorination step, in which the chlorine-containing waste is pulverized and pulverized into fine-grained waste. And

The invention of claim 3 is characterized in that, in claim 1 or 2, after the washing step, a drying step of drying the dechlorinated solid after washing is provided.

According to a fourth aspect of the present invention, in the first to third aspects, in the dechlorination step, dechlorination is performed while introducing steam to prevent inorganic chlorination of chlorine.

According to a fifth aspect of the present invention, in the first to fourth aspects, the dechlorination step is performed under reduced pressure.

A sixth aspect of the present invention is characterized in that, in any of the first to fifth aspects, a preheating step of preheating the crushed waste is provided between the crushing step and the dechlorination step.

A seventh aspect of the present invention is the invention according to any one of the first to sixth aspects, wherein a high-temperature combustion step of burning the pyrolysis gas separated in the separation step in a secondary combustion furnace, and an exhaust gas for removing chlorine in the exhaust gas. And a processing step.

The invention of claim 8 is characterized in that, in any one of claims 1 to 7, a heat exchange step of exchanging exhaust heat of gas between the high-temperature combustion step and the exhaust gas treatment step is provided.

According to a ninth aspect of the present invention, in the eighth aspect, the heat exchange step introduces air into heated air, and the heated air is used for heating in the dechlorination step.

According to a tenth aspect of the present invention, in the eighth aspect, the heat exchange step has a steam generation step of generating steam using waste heat, and the generated steam is used for heating in the dechlorination step. It is characterized by the following.

The invention of claim 11 is the invention according to claim 8, wherein the heat exchange step has a steam generation step of generating steam using waste heat, and the generated steam is used for the dechlorination step. Further, it is characterized in that it is used as a heat source in a preheating step and a drying step.

According to a twelfth aspect of the present invention, in the first aspect, the thermal decomposition step is performed by a direct heat treatment or an indirect heat treatment.

According to a thirteenth aspect of the present invention, in the first aspect, the thermal decomposition step is performed at a decomposition temperature of 300 to 450 ° C.

The invention of claim 14 is characterized in that, in claim 1, the pulverization in the pulverizing step is pulverized to 20 mm or less.

According to a fifteenth aspect of the present invention, in the first aspect, the pulverization in the miniaturization step is pulverized to 10 mm or less.

According to a sixteenth aspect, in the sixth aspect, the preheating temperature of the preheating step is set to 200 to 300 ° C.

The invention of claim 17 is characterized in that, in claim 7, the combustion temperature in the high-temperature combustion step is 750-1000 ° C., and the combustion is performed for at least 2 seconds.

The invention of claim 18 is characterized in that, in claim 12, when the dechlorination step is a direct heat treatment, a gas having a low oxygen concentration or a gas containing no oxygen is passed.

[0028] The invention of a method for producing a dechlorinated fuel according to claim 19 is characterized in that the slurry washed in the water washing step of claim 1 is drained to obtain a slurry-like dechlorinated fuel. .

[0029] The invention of claim 20 is characterized in that the fuel is dried in the drying step of claim 3 to obtain a dechlorinated solidified fuel.

[0031] The invention of a device for producing a dechlorinated fuel according to claim 21 is a pulverizer for pulverizing waste containing chlorine, a method for heating the pyrolyzed waste to thermally decompose it and performing a dechlorination treatment. A dechlorination furnace for performing, a separator for separating the dechlorinated solid and the pyrolysis gas, a pulverizer for pulverizing the separated dechlorinated solid and pulverizing, and the pulverized dechlorinated solid. A washing tank for washing the articles with water and removing inorganic salts, wherein dechlorinated fuel is obtained from chlorine-containing waste.

[22] The invention of an apparatus for producing a dechlorinated fuel according to claim 22 is a dechlorination furnace for thermally decomposing refuse solid fuel (RDF) and performing dechlorination, a dechlorinated solid and pyrolysis gas. And a crusher for pulverizing the separated dechlorinated solids, and a washing tank for washing the crushed dechlorinated solids with water to remove inorganic salts, containing chlorine. It is characterized in that dechlorinated fuel is obtained from solid waste fuel (RDF).

A twenty-third aspect of the present invention is the invention according to the twenty-first or twenty-second aspect, further comprising, after the water washing step, a drying step of drying the dechlorinated solid after the water washing, thereby removing chlorine from waste containing chlorine. It is characterized by obtaining a solidified fuel.

According to a twenty-fourth aspect, in the twenty-first or twenty-second aspect, the dechlorination furnace is provided with a steam introducing means.

The invention of claim 25 is characterized in that, in claim 21 or 22, a pressure reducing means for reducing the pressure in the dechlorination furnace is provided.

The invention of claim 26 is characterized in that, in claim 21 or 22, the dechlorination furnace itself can be rotated or the inside of the furnace can be stirred.

In the present invention, an outline of main specific items of means for solving the above-mentioned problems will be described below.

1) A fine process is provided after the dechlorination process.
In the dechlorination process by thermal decomposition, about 80 wt% or more of the chlorine contained in the waste is dechlorinated and separated as hydrogen chloride. Less than 20% by weight of chlorine remains. This residual chlorine reacts with alkali metals contained in the waste (reaction formulas (1) to (4) shown in the following “Chemical formula 2”) to generate chloride. Since the chloride has a melting point of about 700 to 850 ° C., it is melted in the gasification or combustion process to form a mist and is carried in the gas, condensed in a low-temperature portion of the subsequent process, and causes corrosion and the like. Become.

[0038]

Embedded image Ca (OH) ₂ + 2HCl → CaCl ₂ + 2H ₂ O (1) CaCO ₃ + 2HCl → CaCl ₂ + H ₂ O + CO ₂ (2) NaOH + HCl → NaCl + H ₂ O ... (3) KOH + HCl → KCl + H ₂ O ... (4)

Therefore, in the present invention, after the dechlorination step,
The separated solid is washed with water to dissolve chlorides soluble in water.
Try to separate. At this time, since chlorides are also contained in the solids, the washing effect is enhanced by providing a fine process to pulverize the solids to a fine diameter and then washing them with water. Here, the pulverized particle size to be refined is 1
It is better to be 0 mm or less, preferably 1 to 5 mm or less.

2) In the dechlorination step, thermal decomposition is performed in a steam atmosphere. In the thermal decomposition dechlorination treatment, in the case of a steam atmosphere, the reverse reactions of the above reaction formulas (1) to (4) occur. Therefore, in the present invention, a gas containing water vapor is used as a purge gas to be supplied to the dechlorination furnace containing waste. At this time, the higher the water vapor concentration, the better. The steam can be supplied by effectively utilizing the exhaust heat in the treatment method of the present invention.

3) In the dechlorination step, the inside of the furnace is depressurized. HCl gas decomposed in the thermal decomposition dechlorination process reacts with metals contained in the waste to produce a chlorine compound as a by-product. In order to prevent this, in the present invention, the rate of diffusion of HCl gas out of the system is increased by reducing the pressure in the dechlorination furnace containing waste.

4) In the dechlorination step, a stirring mechanism is provided inside the furnace. As the internal structure of the pyrolysis dechlorination furnace, in order to suppress the generation of the lump of waste plastic softened and melted by heating, a stirring mechanism is provided inside the furnace in the present invention. In addition, this mechanism can efficiently diffuse and degas the HCl gas generated by thermal decomposition from inside the waste layer.

5) In the dechlorination step, a mechanism for rotating the furnace itself is provided. By rotating the dechlorination furnace holding the waste, there is an effect that the adhered wall material of the high boiling point component generated by the thermal decomposition is separated by the moving waste particles.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[First Embodiment] In the present embodiment,
After pyrolysis and dechlorination of waste containing chlorine, it is washed once with water, and inorganic chloride produced as a by-product is dissolved in water and separated to obtain dechlorinated fuel and to perform dechlorination of waste. It is something to do. In addition, a fuel which has been dechlorinated by this treatment can be obtained. Further, the obtained dechlorinated fuel can be subjected to a combustion treatment without a hindrance due to chlorides as a fuel in a gasification or combustion process thereafter, without generating harmful substances such as dioxins. This enables clean processing.

FIG. 1 is a schematic view of an apparatus for performing a dechlorination treatment of waste according to the first embodiment. This apparatus is also an outline of an apparatus for producing a dechlorinated fuel. As shown in FIG. 1, a crusher 12 for reducing the size of a waste 11 containing chlorine to a predetermined size or less (for example, 20 mm or less), a preheater 14 for preheating the crushed waste 13, and a preheated fine A dechlorination furnace 17 for heating the granulated waste 15 at a high steam concentration introduced from the steam introduction means 16 to perform a dechlorination treatment, and a decomposition product 18 thermally decomposed in the dechlorination furnace, A separator 21 for separating into an exhaust gas 19 and a dechlorinated solid 20, and a separated dechlorinated solid 20
Pulverizer 2 for pulverizing powder into a predetermined size or less (5 mm or less)
2 and a washing tank 24 for washing the finely divided dechlorinated solids 23 with water to remove inorganic salts. The waste 11 is dechlorinated. Further, excess water of the slurry after the washing in the washing tank 24 is removed as waste water 25 to obtain a slurry fuel 26 which is a dechlorinated fuel.

The exhaust gas 19 separated by the separator 21 is burned at a high temperature in the secondary combustion furnace 27 to completely decompose the aromatic chlorine compounds and the like in the gas. In the HCl absorption tower, which is a treatment device 29, the chlorine gas is removed and discharged as an exhaust gas 30 to the outside. On the other hand, the wastewater 31 that has absorbed the chlorine gas is treated in the wastewater treatment facility 32 together with the wastewater from the washing tank 24. You.

Here, the preheater 14 melts in order to promote dechlorination, and may not be provided depending on the contents of the waste 11. Further, a preheating means may be provided integrally with the dechlorination furnace 17. That is,
When supplying to the next dechlorination furnace 17 without passing through the preheater 14, the inlet of the dechlorination furnace 17 may be a preheating section, and the required length of the dechlorination furnace 17 may be increased. The preheating temperature of the preheater 14 may be about 200 to 300 ° C., preferably about 250 ° C.

Here, examples of the waste 11 containing chlorine include the following. Garbage discharged from households mixed with inorganic chlorine compounds such as NaCl and MgCl ₂ and plastics containing chlorine. Plastic mixtures containing plastics containing chlorine, such as vinyl chloride. So-called car shredder dust mainly composed of plastic after removing metals from automobiles (Car Shredd)
er Dust: Hereinafter referred to as “CSD”. ).

General refuse discharged from homes contains about 1 to 3 wt% of chlorine. In addition, about 2 to 5 wt% of chlorine is contained in plastic waste discharged from households that are separately collected in some areas. C
Examples of the components of SD are as follows. Polyvinyl chloride (PVC) is used as an instrumentation wire, and about 0.5 to 5 wt% of chlorine is contained in CSD.

[0051]

[Table 1]

[0052]

[Table 2]

Although the waste 11 is pulverized by the pulverizer 12, when the dechlorination furnace 17 is, for example, a different-direction rotating twin-screw or the like, the stirring is facilitated.
It is 30 to 20 mm or less. Further, the smaller the particle size of the pulverization, the better. When a dechlorination furnace such as a rotary kiln is used as the dechlorination furnace 17, 2
It is not necessary to set it to 0 mm or less, and for example, may be set to about 100 mm.

In the dechlorination furnace 16, the preheated refined waste is thermally decomposed.
The temperature is preferably set to 450 ° C. This is because if the temperature exceeds 450 ° C., decomposition of the plastic itself proceeds in addition to the dechlorination reaction, which is not preferable. On the other hand, if the temperature is lower than 300 ° C., the dechlorination efficiency is poor and both are not preferable. The method of heating the dechlorination furnace 17 is not particularly limited, but examples include a direct heating method and an indirect heating method. In the case of the direct heating method, it is preferable to introduce a gas having a low oxygen concentration (amount of O ₂ ) or a gas containing no oxygen from the viewpoint of preventing ignition. However, this is not always the case when heating is performed directly in a nitrogen gas atmosphere. The direct heating method is
Since the gas flow rate is large and the amount of generated exhaust gas increases, the indirect heating method is preferred from the viewpoint of making the apparatus compact.

Further, it was decomposed in the thermal decomposition dechlorination treatment.
In order to prevent the HCl gas from reacting with the metals contained in the waste and producing chlorine compounds as a by-product, the pressure inside the dechlorination furnace is reduced to reduce the diffusion rate of the HCl gas out of the system. Is increasing. As the conditions for decompression, the degree of vacuum is 0.
It is preferably 1 kg / cm ² or less.

Next, FIG. 2 shows the weight loss rate in the thermal decomposition of various plastics (Mitsubishi Heavy Industries technical report, 10 (5) P787).
(1973)). In general, thermoplastics soften and melt at about 120-230 ° C and then thermally decompose at high temperatures. The thermosetting resin is thermally decomposed by heating without being softened or melted. As the plastic containing chlorine in the waste 11, polyvinyl chloride (PV)
C), polyvinylidene chloride. Most of these chlorine-containing plastics desorb most of chlorine as hydrogen chloride in a region of about 170 ° C. to 350 ° C., and when the temperature becomes high, thermal decomposition of other components proceeds. Reaction formula (5) shown in the following “Chemical formula 3”
Shows a model of chlorine desorption.

[0057]

Embedded image

FIG. 3 shows the HCl removal rate of PVC (polyvinyl chloride). From FIG. 3, almost 100% at 300 ° C. or higher.
Dechlorination is required, but a long residence time of tens of minutes is required. As described above, the plastic mixture rapidly begins to decompose at about 250 ° C., and most of it decomposes by about 500 ° C.

Therefore, in the present invention, first, the waste 13 crushed and pulverized is converted into a temperature range (about 260 to 360 ° C.) in which the thermal decomposition rate of hydrocarbons in plastic is as low as possible and the thermal decomposition rate of chlorine Cl is high. In (2), only the chlorine content in the waste is decomposed, and the chlorine is decomposed and separated at a high dechlorination rate of 80 to 90 wt% or more of the initial chlorine content. In this case, the residual solid mainly composed of hydrocarbon components contains about 20% by weight of chlorine in the initial chlorine content, and this chlorine reacts with alkali compounds originally contained in the waste. (See the reactions (1) to (4) above) to produce a chlorine compound,
Chlorine Cl is immobilized. The chloride generated at this time is easily dissolved in water in the washing tank 24 and separated from the solid.

The structure of the pyrolysis dechlorination furnace 17 is provided with a mechanism for stirring and mixing the mixture in the pyrolysis furnace 17 in order to improve the heat exchange performance of the crushed plastics 15. Is preferred. Thus, by providing the stirring / mixing mechanism in the dechlorination furnace 17,
Since the substance adhering to the wall surface is constantly scraped, caulking on the wall surface can be prevented at the same time.

As the dechlorination furnace 17, for example, a rotary kiln type vessel is used to rotate and stir the vessel.
A material having a mixing ability may be used. As described above, when rotating the entire dechlorination furnace for waste, the same effect as described above can be obtained.

Further, as the structure of the dechlorination furnace 17, it is possible to perform a thermal decomposition treatment by indirect heating by flowing a heating medium through the outer cylinder in a double structure.

The decomposition product 18 decomposed by the dechlorination furnace 17 is transferred to a separator 21 in a molten state, where it is separated into an exhaust gas 19 and a dechlorinated solid 20. The exhaust gas 19 separated from the separator 21 is completely combusted in the secondary combustion furnace 27 and contains gas containing hydrogen chloride generated by thermal decomposition. The combustion conditions of this secondary combustion furnace 27 are 7
The temperature is 50 to 1000C, preferably 800 to 900C. This is because the decomposition of hydrocarbons does not start below 750 ° C., which is not preferable, while the decomposition products in the gas are recondensed or soot is generated even when the decomposition is performed above 1000 ° C.
Further, there is a problem in the durability of the furnace, which is not preferable. Further, by setting the combustion time at 850 ° C. for about 2 seconds, dioxins in the exhaust gas can be completely decomposed, which is preferable.

The dechlorinated solid 20 separated from the separator 21 is pulverized by a pulverizer 22. This pulverization is performed by removing the chloride (CaCl ₂ , CaCl ₂ , NaC) contained inside the solid matter 20.
(l, KCl, etc.) are efficiently refined, and the pulverized particle size to be refined is 10 mm or less, preferably 1 to 5 mm or less. In addition,
When the thickness is 1 mm or less, it is not preferable because it becomes a so-called sludge and cannot be efficiently stirred.

According to the above-mentioned method, the waste 11 can be desalinated, and only a small amount of chloride remains in the residue. Therefore, it is easy to make the generated gas and the residue pollution-free. The obtained slurry-like fuel 26 can be handled as it is by using a transfer means such as a pump. For example, coal fuel suspended in water (CWM (Coal Water Miture):
High-concentration coal-water slurry (eg, coal: 70%, water: 30
%)), There is no harmful substance such as dioxins, for example, because the generated gas is dechlorinated, resulting in clean exhaust gas.

[Second Embodiment] In the present embodiment,
As in the first embodiment, the waste containing chlorine is thermally decomposed and dechlorinated, then washed once with water, the by-product inorganic chloride is dissolved in water and separated, and further dried in a drying furnace. It is to let. Further, a dechlorinated solid fuel in a form different from that of the slurry fuel is obtained by drying. Further, in the present embodiment, the exhaust heat of the gas discharged from the secondary combustion furnace is effectively used in the dechlorination process.

FIG. 4 is a schematic diagram of an apparatus for producing a dechlorinated fuel according to the second embodiment. As shown in FIG. 4, a crusher 12 for pulverizing a waste 11 containing chlorine to a predetermined size or less (for example, 20 mm or less), and a crushed waste 13
And a dechlorination furnace 17 for heating the preheated and finely divided waste 15 in a state where the concentration of steam introduced from the steam introduction means 16 is high to perform a dechlorination treatment.
And a separator 2 for separating a decomposition product 18 thermally decomposed in the dechlorination furnace into an exhaust gas 19 and a dechlorinated solid 20.
1, a pulverizer 22 for pulverizing the separated dechlorinated solid matter 20 into a predetermined size or less (for example, 5 mm or less), and a washing tank for washing the finely divided dechlorinated solid matter 23 with water to remove inorganic salts. 24 and a drying furnace 41 for drying the solid content after washing with water. The solid content dried in the drying furnace 41 can be used as a dechlorinated solid fuel 42.

In the present embodiment, the secondary combustion furnace 27
A heat exchanger 43 is provided between the steam generator and the exhaust gas treatment device 29 to recover combustion heat, and steam is generated by a steam generator 44 having a water supply means. The steam 16 obtained here is introduced into the dechlorination furnace 17 so as to suppress generation of chloride.

In the present embodiment, the separately introduced heating gas 45 is used as a heat source for heating the dechlorination furnace 17. The gas heated in the dechlorination furnace 17 is supplied to the lines 46 and 4 as a heat source of the preheater 14 and a heat source of the drying furnace 41.
7. Note that the exhaust gas 48 in the drying furnace 41 is separately subjected to exhaust gas treatment.

In the above method, the waste 11 can be dechlorinated, and only a small amount of chloride remains in the residue, so that the generated gas and the residue can be easily polluted. Also,
The dechlorinated solid fuel 42 is led to the next step of gasification, oiling, and the like, and the organic matter (hydrocarbon) is gasified or oiled. On the other hand, when this is burned as a fuel, the generated gas is harmless because it is dechlorinated, and since only a small amount of chloride remains in the residue, it is easy to make the residue pollution-free. . Also, by installing the heat exchanger 43,
Exhaust heat can be used effectively, and steam can be generated by the obtained heat, and the steam can be used in the dechlorination furnace 17, and the heat can be used effectively.

[Third Embodiment] In the present embodiment,
As in the second embodiment, the waste containing chlorine is thermally decomposed and dechlorinated, then washed once with water, the by-product inorganic chloride is dissolved in water and separated, and further dried in a drying furnace. By doing so, a dechlorinated solid fuel is obtained, but the form of utilization of the exhaust heat of the gas discharged from the secondary combustion furnace is different.

FIG. 5 is a schematic diagram of an apparatus for producing a dechlorinated fuel according to the third embodiment. As shown in FIG. 5, a pulverizer 12 for pulverizing a waste 11 containing chlorine to a predetermined size or less (for example, 20 mm or less), and a pulverized waste 13
And a dechlorination furnace 17 for heating the preheated and finely divided waste 15 in a state where the concentration of steam introduced from the steam introduction means 16 is high to perform a dechlorination treatment.
And a separator 2 for separating a decomposition product 18 thermally decomposed in the dechlorination furnace into an exhaust gas 19 and a dechlorinated solid 20.
1, a pulverizer 22 for pulverizing the separated dechlorinated solid matter 20 into a predetermined size or less (for example, 5 mm or less), and a washing tank for washing the finely divided dechlorinated solid matter 23 with water to remove inorganic salts. 24 and a drying furnace 41 for drying the solid content after washing with water. The solid content dried in the drying furnace 41 is obtained as a dechlorinated fuel 42.

In the present embodiment, the secondary combustion furnace 27
A heat exchanger 51 is provided between the heat exchanger 51 and the exhaust gas treatment device 29 to heat the air 53 introduced by the blower 52 and use it together with the separately introduced heating gas 54 as a heat source for heating the dechlorination furnace 17. I have. As in the second embodiment, the gas heated in the dechlorination furnace 17 is supplied via a line 46 as a heat source of the preheater 14 and a heat source of the drying furnace 41. The gas heated in the dechlorination furnace 17 is used as a heat source of the preheater 14 and a heat source of the drying furnace 41 in the line 55,
It is supplied via 56. Note that the exhaust gas 48 in the drying furnace 41 is separately subjected to exhaust gas treatment.

The dechlorinated fuel 42 after the dechlorination treatment (thermal decomposition) by the above-mentioned method is led to the next gasification, oiling or burning step, where organic substances (hydrocarbons) are gasified, oiled or converted. It is burned. During this combustion, the generated gas is harmless because it has been dechlorinated, and since only a small amount of chloride remains in the residue, the residue can be easily rendered harmless. In addition, by installing the heat exchanger 43, the exhaust heat can be used effectively, and the obtained heat can be used to generate steam, and the steam can be used in the dechlorination furnace 17, and the heat can be used effectively. .

[Fourth Embodiment] In the present embodiment,
As in the third embodiment, the waste containing chlorine is thermally decomposed and dechlorinated, then washed once with water, and the inorganic chloride produced as a by-product is dissolved in water and separated, and further dried in a drying furnace. Let
In addition to obtaining dechlorinated solid fuel, it aims to use waste heat in the secondary combustion furnace, but uses only RDF (Rdfuse Derived Fuel) from simple waste for treatment. The differences are. Since the same applies to the case of using RPF (waste plastic solid fuel), the present invention will be described below using RDF.

FIG. 6 is a schematic diagram of an apparatus for producing a dechlorinated fuel according to the fourth embodiment. As shown in FIG. 6, an RDF (dust solidified fuel) 61 containing chlorine is supplied to a steam introducing means 1.
6, a dechlorination furnace 17 for heating and dechlorinating in a state where the water vapor concentration is high, and a decomposition product 18 thermally decomposed in the dechlorination furnace are converted into an exhaust gas 19 and a dechlorinated solid 20. A crusher 22 for pulverizing the separated dechlorinated solid matter 20 into a predetermined size or less (for example, 5 mm or less), and a finely divided dechlorinated solid matter 2
RD containing chlorine, which comprises a washing tank 24 for washing inorganic material 3 to remove inorganic salts and a drying furnace 41 for drying solids after washing.
F (dust solidified fuel) 61 is subjected to a dechlorination treatment, and a solid content dried in the drying furnace 41 is obtained as a dechlorinated fuel 42.

In the present embodiment, the secondary combustion furnace 27
A heat exchanger 51 is provided between the heat exchanger 51 and the exhaust gas treatment device 29 to heat the air 53 introduced by the blower 52 and heat the dechlorination furnace 17 together with the heating gas 54 separately introduced. Note that, similarly to the second embodiment, the dechlorination furnace 17 is used.
The gas after the heating in is supplied through lines 55 and 56 as a heat source of the preheater 14 and a heat source of the drying furnace 41.

According to the above method, chlorine-containing RDF
The (debris-solidified fuel) 61 is thermally decomposed, and the dechlorinated fuel 42 after the dechlorination (thermal decomposition) is led to the next gasification or combustion step, where the organic matter (hydrocarbon) is gasified or burned. It is processed. During this combustion, the generated gas is harmless because it has been dechlorinated, and since only a small amount of chloride remains in the residue, the residue can be easily rendered harmless. In addition, by installing the heat exchanger 43, the exhaust heat can be used effectively, and the obtained heat can be used to generate steam, and the steam can be used in the dechlorination furnace 17. The production of products is suppressed.

[Fifth Embodiment] In the present embodiment,
As in the fourth embodiment, the object to be treated is one using RDF (solidified fuel), and the dechlorination treatment method is the same as in the second embodiment.

FIG. 7 is a schematic diagram of an apparatus for producing a dechlorinated fuel according to the fifth embodiment. As shown in FIG. 7, an RDF (garbage solidified fuel) 61 containing chlorine is supplied to a steam introducing means 1.
6, a dechlorination furnace 17 for heating and dechlorinating in a state where the water vapor concentration is high, and a decomposition product 18 thermally decomposed in the dechlorination furnace are converted into an exhaust gas 19 and a dechlorinated solid 20. A crusher 22 for pulverizing the separated dechlorinated solid matter 20 into a predetermined size or less (for example, 5 mm or less), and a finely divided dechlorinated solid matter 2
RD containing chlorine, which comprises a washing tank 24 for washing inorganic material 3 to remove inorganic salts and a drying furnace 41 for drying solids after washing.
F (dust solidified fuel) 61 is subjected to a dechlorination treatment, and a solid content dried in the drying furnace 41 is obtained as a dechlorinated fuel 42.

In the present embodiment, the secondary combustion furnace 27
A heat exchanger 43 is provided between the apparatus and the exhaust gas processing apparatus 29 to recover combustion heat, generate steam in a steam generator 44, and supply the steam to the dechlorination furnace 17. The heat exchanged in the steam generator 44 heats the dechlorination furnace 17 together with the heating gas 45 introduced separately. Also,
The gas heated in the dechlorination furnace 17 is supplied via a line 46 as a heat source of the preheater 14 and a heat source of the drying furnace 41.

According to the above method, chlorine-containing RDF
The (debris-solidified fuel) 61 is thermally decomposed, and the dechlorinated fuel 42 after the dechlorination (thermal decomposition) is led to the next gasification or combustion step, where the organic matter (hydrocarbon) is gasified or burned. It is processed. During this combustion, the generated gas is harmless because it has been dechlorinated, and since only a small amount of chloride remains in the residue, the residue can be easily rendered harmless.

[0083]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments showing the effects of the present invention will be described below, but the present invention is not limited to these embodiments.

One embodiment of the present invention will be described with reference to the apparatus shown in FIG. As shown in FIG. 4, a waste 11 containing a plastic containing chlorine such as polyvinyl chloride and polyvinylidene chloride is supplied to a crusher 12 and crushed to about 20 mm or less. The crushed waste is supplied to the preheater 3,
Preheat to ~ 280 ° C. The preheated waste 15 is
It is supplied to the dechlorination furnace 17 and is heated to 320 to 330 ° C., and the chlorine portion in the chlorine-containing plastic is mainly decomposed into HCl gas. Gas generated by thermal decomposition (HC
(including l) 19 was separated by a separator 21 in a molten state and supplied to a secondary combustion furnace 27. Here, the combustible gas in the exhaust gas 19 was burned at 850 ° C. This combustion was for 2 seconds. Further, the combustion gas 28 was guided to the heat exchanger 43, and after separating and removing the HCl gas in the exhaust gas treatment device 29, the combustion gas 28 was discharged as the exhaust gas 30 and the waste water 31.

On the other hand, the waste which has been dechlorinated in the dechlorination furnace 17 is separated into exhaust gas by the separator 21 and then separated into solids 20.
Then, it was supplied to the pulverizer 22 and pulverized to a fine substance of about 5 mm or less. The crushed solids 23 are put into a washing tank 24, and salts soluble in water are dissolved and separated. The solid after washing is dried in a drying furnace 41 and taken out as a dechlorinated solid fuel 42. Then, it is supplied to the gasification, oilification and combustion processes. The heat of combustion generated in the secondary combustion furnace 27 is recovered as steam by a heat exchanger (recovery temperature: 800 ° C.) 43 and a steam generator 44, and the recovered steam 16
Was used as a purge gas for the dechlorination furnace 17.

[Examples 1 to 8] Examples 1 to 4 were obtained by using the above-mentioned apparatus to dechlorinate wastes having the properties shown in Table 3 below as raw materials and conditions. As a result, a solid fuel with a low residual dechlorination concentration could be produced. The results are shown in Table 3. Further, Examples 5 to 8 were cases in which pressure was applied to the dechlorination furnace 17 under the same conditions as in Examples 1 to 4 to perform dechlorination under reduced pressure. The results are shown in Table 4. Here, the dechlorination furnace 17 used in the present embodiment uses a heating furnace with a twin-screw impeller, and is an indirect heating method by heating an outer cylinder heating medium, and the processing scale of the dechlorination furnace is 300 (kg / d). It is.

The solid 2 separated from the dechlorination furnace 17
In Comparative Examples 1 to 4, the sample No. 0 was not subjected to the crushing step and the washing step. The results are shown in Table 5.

[0088]

[Table 3]

[Table 4]

[Table 5]

As shown in Tables 3 to 5, in this embodiment, the residual Cl concentration was 0.08 to 0.21% by weight.
Was extremely low, but in the case of the comparative example, it was 0.7.
The content was as high as 8% by weight or more, and a solid fuel having a low residual chlorine concentration could be produced by this example. Also,
It was found that the decompression treatment significantly improved the efficiency of the dechlorination treatment.

Example 9 A dechlorination treatment was performed using CSD (car shredder dust) having the composition shown in Table 6 below as a raw material. Here, the dechlorination furnace 1 used in this example was used.
7 is a rotary kiln type pyrolysis furnace (inner diameter 350 x length
4,100 (mm)), and the operating conditions depend on the kiln inlet temperature.
The temperature was 420 ° C and the outlet temperature was 330 ° C. The average residence time in the kiln was 26 minutes.

[0091]

[Table 6]

According to the present embodiment, the solid fuel recovery rate is 73.5
(Wt%), and a solid fuel having a residual chlorine concentration of 0.21 (wt%) could be produced. When the inner wall of the rotary kiln was observed, almost no fusion of plastic or caulking to the wall was observed.

[0093]

As described above, according to the first aspect of the present invention, a dechlorination step of thermally decomposing a chlorine-containing waste and performing a dechlorination treatment is provided. A separation step of separating the cracked gas, a pulverization step of pulverizing the separated dechlorinated solid to make it fine, and a water washing step of washing the pulverized dechlorinated solid with water to remove inorganic salts Harmful organic chlorine compounds such as dioxins in the treatment of waste such as general garbage, plastic mixtures containing chlorine-containing plastics such as vinyl chloride, and plastics containing chlorine and car shredder dust containing inorganic components And the amount of waste such as gasification residue and combustion ash can be suppressed, and a slurry-like fuel can be obtained, which can be burned together with CWM.

According to [Claim 2], the method according to Claim 1 includes a pulverizing step of pulverizing the waste containing chlorine to pulverize the waste containing chlorine in the stage preceding the dechlorination step to obtain the pulverized waste. The area of the dechlorination reaction increases due to the finer particles, and the dechlorination reaction becomes efficient.

According to [Claim 3], the method according to claim 1 or 2, further comprising, after the water washing step, a drying step of drying the dechlorinated solid after the water washing. can do.

According to [Claim 4], in the above-described dechlorination step, since steam is introduced in the dechlorination step, inorganic chlorination of chlorine in the dechlorination reaction can be prevented.

According to [Claim 5], in the above-mentioned dechlorination step, since the treatment is carried out under reduced pressure, the decomposed HCl gas reacts with the metals contained in the waste to form an inorganic material. By-producing chlorine compounds can be suppressed, and the diffusion rate of HCl gas out of the system can be increased.

According to claim 6, the preheating step of preheating the pulverized waste is provided between the pulverizing step and the dechlorinating step in claim 1 to 5, so that the plastics can be melted. Promotes efficient dechlorination.

According to claim 7, the high-temperature combustion step in which the pyrolysis gas separated in the separation step is burned in a secondary combustion furnace according to claim 1 to 6, and an exhaust gas for removing chlorine in the exhaust gas. Since it has a treatment step, complete decomposition of organic chlorinated substances and the like in exhaust gas and decomposition treatment of hydrocarbons are performed, and hydrogen chloride in the gas is removed.

According to [claim 8], a heat exchange step of exchanging exhaust heat of gas is provided between the high-temperature combustion step and the exhaust gas treatment step in claim 1 to 7, so that the dechlorination treatment step is performed. The heat generated in the above can be effectively used.

According to [claim 9], in claim 8, the heat exchange step introduces air into heated air and uses the heated air for heating in the dechlorination step. Can be used efficiently.

According to a tenth aspect, in the eighth aspect, the heat exchange step has a steam generation step of generating steam using waste heat, and the generated steam is used for heating in the dechlorination step. Therefore, heat generated in the dechlorination process can be efficiently used.

According to [claim 11], in claim 8, the heat exchange step has a steam generation step of generating steam using waste heat, and the generated steam is used for the dechlorination step. Furthermore, since it is used as a heat source in the preheating step and the drying step, the heat generated in the dechlorination step can be used efficiently.

According to [Claim 12], since the thermal decomposition step is performed by direct heat treatment or indirect heat treatment in claim 1, waste is efficiently dechlorinated.

According to [Claim 13], since the decomposition temperature in the thermal decomposition step is set at 300 to 450 ° C., the waste is efficiently dechlorinated.

According to [claim 14], in claim 1, the area of the dechlorination reaction is increased by the pulverization of the waste which is obtained by pulverizing the pulverization step in the pulverization step to 20 mm or less, so that the dechlorination reaction can be performed efficiently. Becomes

According to [claim 15], in claim 1, the pulverization in the micronizing step is pulverized to 10 mm or less, so that the cleaning efficiency in the water washing treatment is improved after the pulverization is performed to a fine diameter.

According to [claim 16], in claim 6, since the preheating temperature in the preheating step is set to 200 to 300 ° C., the melting of plastics is promoted and the dechlorination reaction is made efficient. .

According to [claim 17], in claim 7, the combustion temperature in the high-temperature combustion step is 750-1000 ° C. and combustion is performed for at least 2 seconds or more. Complete decomposition processing can be performed.

According to [claim 18], in claim 12, when the dechlorination step is a direct heat treatment, a gas having a low oxygen concentration or a gas containing no oxygen is circulated, so that ignition in the furnace is prevented. can do.

According to the method for producing a dechlorinated fuel of claim 19, since the slurry washed in the water washing step of claim 1 is drained, a slurry-like dechlorinated fuel is obtained. Slurry-like fuel can be burned with coal fuel (CWM).

According to [claim 20], since the dechlorinated solidified fuel is obtained by drying in the drying step of claim 3, the obtained dechlorinated solid fuel is subjected to the steps of gasification, oilification, combustion and the like. It can be treated as a new energy source, and the exhaust gas does not contain chlorine, so it is clean with no generation of dioxins.

According to the apparatus for producing dechlorinated fuel according to claim 21, a crusher for crushing waste containing chlorine, a heat treatment for the finely divided waste to thermally decompose it, and a dechlorination treatment. A dechlorination furnace for performing, a separator for separating the dechlorinated solid and the pyrolysis gas, a pulverizer for pulverizing and separating the separated dechlorinated solid, and the pulverized dechlorinated solid. A water washing tank is provided for washing the material to remove inorganic salts. Since a dechlorinated fuel is obtained from waste containing chlorine, a slurry fuel can be efficiently produced from the waste.

According to the apparatus for producing a dechlorinated fuel of claim 22, a dechlorination furnace for thermally decomposing the refuse solid fuel (RDF) and performing a dechlorination treatment, a dechlorinated solid and a pyrolysis gas And a crusher for finely separating the separated dechlorinated solids, and a washing tank for washing the crushed dechlorinated solids with water to remove inorganic salts, containing chlorine. A slurry fuel dechlorinated from refuse solid fuel (RDF) can be efficiently produced.

According to the twenty-third aspect, in the twenty-first or the twenty-second aspect, after the water washing step, a drying step of drying the dechlorinated solid after the water washing is provided. Since chlorinated solid fuel is obtained, dechlorinated solid fuel can be efficiently produced from waste.

According to [claim 24], in claim 21 or 22, since the steam introducing means is provided in the dechlorination furnace, inorganic chlorination of chlorine in the dechlorination reaction can be prevented.

According to [Claim 25], since the pressure reducing means for reducing the pressure in the dechlorination furnace is provided in Claim 21 or 22, the decomposed HCl gas reacts with the metals contained in the waste. By-products of chlorine inorganic compounds can be suppressed, and the diffusion rate of HCl gas out of the system can be increased.

According to [claim 26], in claim 21 or 22, since the dechlorination furnace itself can be rotated or the inside of the furnace can be stirred, the dechlorination reaction can be performed efficiently.

[Brief description of the drawings]

FIG. 1 shows a schematic diagram of an apparatus for producing a dechlorinated fuel according to a first embodiment of the present invention.

FIG. 2 is a graph showing a weight loss rate in thermal decomposition of various plastics.

FIG. 3 is a graph showing the HCl removal rate of PVC (polyvinyl chloride).

FIG. 4 is a schematic view of a dechlorinated fuel production apparatus according to a second embodiment of the present invention.

FIG. 5 is a schematic view of an apparatus for producing a dechlorinated fuel according to a third embodiment of the present invention.

FIG. 6 shows a schematic diagram of an apparatus for producing a dechlorinated fuel according to a fourth embodiment of the present invention.

FIG. 7 shows a schematic diagram of an apparatus for producing a dechlorinated fuel according to a fifth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 waste 12 crusher 13 refined waste 14 preheater 15 preheated refined waste 16 steam introduction means 17 dechlorination furnace 18 decomposition product 19 exhaust gas 20 dechlorinated solid 21 separator 22 crusher 23 Dechlorinated solids 24 Rinse tank 25 Drainage 26 Slurry fuel 27 Secondary combustion furnace 28 Combustion gas 29 Exhaust gas treatment device 30 Exhaust gas 31 Drainage 32 Wastewater treatment equipment 41 Drying furnace 42 Dechlorinated solid fuel 43 Heat exchanger 44 Steam generation Container 45 Heated gas 51 Heat exchanger 52 Blower 53 Air 54 Heated gas 61 RDF (solidified fuel)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B29B 17/00 ZAB B09B 3/00 302A 304P (72) Inventor Hiroshi Koga Eno Urakuru, Hikoshima Shimonoseki City, Yamaguchi Prefecture No. 16-1 F-term in Shimonoseki Shipyard, Mitsubishi Heavy Industries, Ltd. (Reference) 4F074 AA35 AA97L EA07 EA24 EA34 EA72 4F201 AA14 AA15 AA50 AR06 AR12 BA04 BA05 BC01 BC02 BC10 BC12 BC25 BN01 BN21 BN29 BP08 A27 BP20 BB01 BB02 BB03 BB04 BB10 BB11 BB13

Claims (26)

[Claims] 1. A dechlorination step of thermally decomposing a chlorine-containing waste and performing a dechlorination treatment, a separation step of separating a dechlorinated solid and a pyrolysis gas, and a separated dechlorinated solid. And a water washing step of washing the finely divided dechlorinated solid with water to remove inorganic salts. 2. The dechlorination of waste according to claim 1, further comprising: a pulverization step of pulverizing and pulverizing the waste containing chlorine into pulverized waste before the dechlorination step. Processing method. 3. The method for dechlorination of waste according to claim 1, further comprising a drying step of drying the dechlorinated solid after the washing, after the washing step. 4. The method according to claim 1, wherein in the dechlorination step, dechlorination is performed while introducing steam to prevent inorganic chlorination of chlorine. 5. The method for dechlorination of waste according to claim 1, wherein the dechlorination step is performed under reduced pressure. 6. The dechlorination method of waste according to claim 1, further comprising a preheating step of preheating the pulverized waste between the pulverization step and the dechlorination step. 7. The method according to claim 1, further comprising a high-temperature combustion step of burning the pyrolysis gas separated in the separation step in a secondary combustion furnace, and an exhaust gas treatment step of removing chlorine in the exhaust gas. Characteristic method of dechlorination of waste. 8. The method for dechlorination of wastes according to claim 1, further comprising a heat exchange step of exchanging heat of exhaust gas between said high-temperature combustion step and said exhaust gas treatment step. 9. The method for dechlorination of waste according to claim 8, wherein the heat exchange step introduces air into heated air, and uses the heated air for heating in the dechlorination step. 10. The waste according to claim 8, wherein the heat exchange step has a steam generation step of generating steam using waste heat, and the generated steam is used for heating in the dechlorination step. Dechlorination treatment method. 11. The method according to claim 8, wherein the heat exchange step has a steam generation step of generating steam using waste heat, and the generated steam is used in the dechlorination step, and further, in the preheating step and the drying step. A method for dechlorination of waste, wherein the method is used as a heat source. 12. The method for dechlorination of waste according to claim 1, wherein the thermal decomposition step is performed by direct heat treatment or indirect heat treatment. 13. The method for dechlorination of waste according to claim 1, wherein the decomposition temperature in the pyrolysis step is 300 to 450 ° C. 14. The method according to claim 1, wherein the crushing in the crushing step is crushed to 20 mm or less. 15. The method for dechlorination of waste according to claim 1, wherein the pulverization in the micronizing step is pulverized to 10 mm or less. 16. The method for dechlorination of waste according to claim 6, wherein the preheating temperature in the preheating step is 200 to 300 ° C. 17. The method for dechlorination of waste according to claim 7, wherein the combustion temperature in the high-temperature combustion step is 750 to 1000 ° C., and the combustion is performed for at least 2 seconds. 18. The method according to claim 12, wherein, when the dechlorination step is a direct heat treatment, a gas having a low oxygen concentration or a gas containing no oxygen is passed. 19. A method for producing a dechlorinated fuel, characterized by draining the slurry washed in the water washing step of claim 1 to obtain a slurry-like dechlorinated fuel. 20. A method for producing a dechlorinated fuel, comprising drying in the drying step of claim 3 to obtain a dechlorinated solidified fuel. 21. A crusher for crushing chlorine-containing waste, a dechlorination furnace for heating and thermally decomposing the fine-grained waste, and a dechlorination treatment; a dechlorinated solid and a pyrolysis gas; A crusher for crushing the separated dechlorinated solids to make them finer, and a washing tank for washing the crushed dechlorinated solids with water to remove inorganic salts, An apparatus for producing a dechlorinated fuel, wherein a slurry-like dechlorinated fuel is obtained from waste containing chlorine. 22. A dechlorination furnace for thermally decomposing a refuse solid fuel (RDF) and performing a dechlorination treatment, a separator for separating a dechlorinated solid and a pyrolysis gas, and a separated dechlorinated solid. A crusher for pulverizing the material, and a washing tank for washing the crushed dechlorinated solid with water to remove inorganic salts. An apparatus for producing a dechlorinated fuel, comprising: 23. The method according to claim 21, further comprising, after the water-washing step, a drying step of drying the water-washed dechlorinated solid matter, and obtaining a dechlorinated solid fuel from waste containing chlorine. Characteristic dechlorinated fuel production equipment. 24. The apparatus for producing a dechlorinated fuel according to claim 21, wherein a steam introduction means is provided in the dechlorination furnace. 25. The apparatus for producing a dechlorinated fuel according to claim 21, further comprising a pressure reducing means for reducing the pressure in the dechlorination furnace. 26. The apparatus for producing a dechlorinated fuel according to claim 21, wherein the dechlorination furnace itself can be rotated or the inside of the furnace can be stirred.