JP2002364817A - Method for melting wastes - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for melting wastes which enables continuous discharge of molten slag, and prevents emission of carbon dioxide as well as increase of expense for melting treatment and reduction of waste treatment capacity. SOLUTION: The method for melting wastes comprises blowing hot air by a plasma torch 1 to a coke layer 25 formed on the bottom of a shaft furnace with supplied coke and wastes, burning and gasifying the wastes in an atmosphere of not more than a stoichiometric air quantity required for the combustibles, and discharging the residue outside the furnace as molten slag. The electric energy supplied to the plasma torch 1 is controlled in accordance with variation of the lower calorific value of the wastes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for melting garbage, which burns and gasifies garbage in a furnace, and melts the remaining ash and char in the same furnace to form molten slag and discharges the slag to the outside of the furnace. In particular, the present invention relates to a melting method for treating municipal waste generated by local residents.

[0002]

2. Description of the Related Art Conventionally, refuse has generally been incinerated in a stalker furnace or a fluidized-bed furnace, and the incinerated ash is landfilled. However, since the volume of incinerated ash has not been reduced sufficiently during landfill disposal recently, and the incinerated ash is scattered during landfill disposal and adversely affects the surrounding environment. It is recommended to landfill it. Therefore, there are two methods of melting garbage, one to convert incineration ash discharged from a conventional incinerator into molten slag in a separate melting furnace, and another to convert garbage into molten slag in one furnace. There are things.

[0003] As a method for converting garbage into molten slag in one furnace, for example, Japanese Patent Publication No. Sho 56-2243 (prior art-1) and Japanese Patent Publication No. Sho 60-11766 (prior art-
2) and the like. The melting method described in the prior arts 1 and 2 uses combustion of coke and refuse as a heating source and supplies oxygen-enriched air to burn it, and the molten slag is intermittently discharged. Things.

[0004]

However, in the above-mentioned prior arts 1 and 2, a separate device for producing oxygen-enriched air is required, and a discharge port is opened to intermittently discharge molten slag. There is a problem that the work of closing and closing is required. In addition, the refuse of general waste generated by local residents, which is the subject of the melting method of the present invention, has a relatively large change in the lower heating value. The fluctuations in the lower calorific value include long-term fluctuations such as a decrease in the lower calorific value due to an increase in garbage in summer due to seasonal factors, and an increase in the lower calorific value due to an increase in plastic waste in winter. Fluctuations and short-term fluctuations in daily life, for example, garbage in one time period is wet and low calorific value is low, and garbage in another time period is dry and low calorific value is high. is there. In the prior arts 1 and 2 described above, coke is used as a heating source (other than the burning of refuse), so that the fluctuation of the lower calorific value of refuse is adjusted by adjusting the supply amount of coke. The method is effective for long-term fluctuations. However, it is difficult to appropriately adjust the amount of coke supplied with respect to short-term fluctuations in the lower calorific value of garbage (since the supply of coke is generally intermittent). Since it takes a long time for the coke that has started combustion to function as a heating source, it is not sufficient to respond by adjusting the coke supply amount. Insufficient coke supply will hinder the melting of garbage, so the coke supply will have to be adjusted excessively, resulting in increased coke purchase costs and increased melt processing costs. is there. Also,
The supply of coke more than necessary increases the heat load of the furnace, and there is also a problem that the amount of refuse treated in the furnace decreases accordingly. Further, supplying waste coke more than necessary to dispose of garbage unnecessarily increases carbon dioxide emission and is not preferable from the viewpoint of preventing global warming. The present invention has solved the above-mentioned problems, has enabled continuous discharge of molten slag, and has prevented an increase in melting processing cost and a decrease in the amount of refuse disposal in a furnace, as well as preventing carbon dioxide emissions. An object of the present invention is to provide a method for melting garbage.

[0005]

SUMMARY OF THE INVENTION Fluctuations in the lower calorific value of municipal solid waste generated by local residents are usually in the range of 3000 to 12000 KJ / Kg. The present inventors have conducted various studies and experiments in order to solve the above-mentioned problems, and as a result, in a shaft furnace using coke and a plasma torch as a heating source, dust of 1000 kg / g within a range of fluctuation of a lower heating value. It has been found that a coke supply amount of 30 Kg / hr is sufficient for performing gasification and melting while maintaining a stable residue of hr. Further, the present inventors have found that the range of variation of the lower heating value is from 9800 to 1
In the range of a high value of 2000 KJ / Kg, in order to gasify and melt the dust at 1000 Kg / hr,
It has been found that a coke supply amount of 20 kg / hr is sufficient.

Accordingly, the first invention of the present application provides a plasma torch so that coke and dust are supplied into a shaft furnace, a coke layer is formed at the bottom of the furnace, and hot air is blown toward the coke layer. This is a method of melting garbage in which the garbage is burned and gasified in an atmosphere having a stoichiometric amount of air less than that of the flammable substances, and the residue is discharged out of the furnace as molten slag. On the other hand, there is provided a method for melting garbage, wherein the amount of electric power supplied to the plasma torch is adjusted.

In a second aspect of the present invention, a plasma torch is provided such that coke and dust are supplied into a shaft furnace, a coke layer is formed at the bottom of the furnace, and hot air is blown toward the coke layer. Combustion and gasification of garbage in an atmosphere below the stoichiometric amount of air for those combustibles
A method for melting dust that discharges the residue as a molten slag outside the furnace. For a short-term decrease in the lower heating value of the dust, the amount of power supplied to the plasma torch is increased, and the lower heating value of the dust is increased. The method for melting garbage is characterized in that the amount of electric power supplied to the plasma torch is reduced with respect to the short-term increase of the refuse.

In a third aspect of the present invention, a plasma torch is provided such that coke and dust are supplied into a shaft furnace, a coke layer is formed at the bottom of the furnace, and hot air is blown toward the coke layer. Combustion and gasification of garbage in an atmosphere below the stoichiometric amount of air for those combustibles,
A method for melting garbage that discharges the residue as molten slag outside the furnace.For a long-term decrease in the lower calorific value of the garbage, the amount of coke supplied to the shaft furnace is increased to reduce the amount of garbage. A method for melting garbage, characterized in that the amount of coke supplied into the shaft furnace is reduced with respect to a long-term increase in the calorific value.

In a fourth aspect of the present invention, a plasma torch is provided such that coke and dust are supplied into a shaft furnace, a coke layer is formed at the bottom of the furnace, and hot air is blown toward the coke layer. Combustion and gasification of garbage in an atmosphere below the stoichiometric amount of air for those combustibles,
A method for melting dust that discharges the residue as a molten slag outside the furnace. For a short-term decrease in the lower heating value of the dust, the amount of power supplied to the plasma torch is increased, and the lower heating value of the dust is increased. For a short-term increase in the amount of electric power supplied to the plasma torch, the amount of electric power supplied to the plasma torch should be reduced. A method for melting garbage, characterized in that the amount of coke is increased and the amount of coke supplied to the shaft furnace is reduced with respect to a long-term increase in the lower heating value of the garbage.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The dust melting method of the present invention comprises forming a coke layer on the bottom of a shaft furnace, heating the coke layer with hot air blown from a plasma torch, and burning a part of the coke layer. This heat causes the waste accumulated on the coke layer to burn and gasify in an atmosphere with a stoichiometric amount of air or less, and the resulting ash is converted into molten slag in the coke layer and discharged outside the furnace. To discharge. Since ash and char form molten slag, when cooled, the molten slag becomes glassy material, reducing the volume of ash and char to about 1/5, and heavy metals etc. are confined in the glassy material. No elution.

In the melting method of the present invention, the hot air of the plasma torch is blown toward the coke layer. The amount of hot air from the plasma torch is the sum of the plasma air and the shroud air. The temperature of the hot air from the plasma torch is 1000 ~ 2500 ℃, so that the coke layer is heated and a part of the coke layer is burned by the oxygen in the hot air, so the temperature in the coke layer is stable at about 1500 ℃ Can be maintained. Set the coke layer temperature to 150
In order to maintain the temperature at 0 ° C., for example, only by the heat of combustion of coke, oxygen-enriched air is required to maintain the temperature. However, in the melting method of the present invention, a plasma torch is used. The hot air may be ordinary air.

The blowing pressure of the plasma air and the shroud air of the plasma torch is a positive pressure of 14.7 KPa.
It becomes a positive pressure of ５5 KPa. The pressure near the bottom of the furnace is 5KP
When the temperature exceeds a, when the molten slag discharge port communicates with the inside of the furnace, the hot air of about 1500 ° C. in the furnace is strongly blown out,
As a result, there is a disadvantage that a large amount of heat in the furnace is taken out of the furnace, and there is a danger of burning people who work around the furnace. The pressure near the furnace bottom is 0.3 KPa
When the pressure is below the range, the force for pushing out the molten slag generated by the differential pressure with the outside air becomes small, and it becomes difficult to discharge the molten slag.

Since the melting method of the present invention uses a plasma torch in a shaft furnace, the furnace has an extremely rugged structure without a movable body, and the plasma torch has excellent operability, so that the furnace operation is difficult. Easy to do. Since the melting method of the present invention has a structure in which the furnace bottom can be separated,
Inspection and repair around the furnace bottom and the plasma torch, which are exposed to the most severe conditions both in temperature and environment in the furnace, can be performed extremely easily.

Next, an embodiment of the method for melting dust according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a system of a refuse melting method according to the present invention, and FIG. 2 is a sectional view showing a refuse melting method of the present invention. In FIGS. 1 and 2, reference numeral 2 denotes a furnace body, and a plasma torch 1 and a first tuyere 3 and a second tuyere 4 are provided above the plasma torch 1 near the furnace bottom. In this embodiment, the plasma torch 1 is provided at two places on the circumference of the furnace body at the same height, and the direction of the hot air blown out from the plasma torch is the diameter direction of the furnace body in a plane, and the direction of the furnace bottom in the elevation. The direction was the direction of the intersection of the bottom and the vertical part.
The first tuyere 3 and the second tuyere 4 were also provided at six locations on the circumference. As the air blown from the first tuyere 3 and the second tuyere, the air that has been heated to a high temperature by exchanging heat with a high-temperature gas in a secondary combustion furnace described later by a heat exchanger is used. The furnace body 2 has a refractory material 202 applied inside an outer shell 201. Further, in the present embodiment, the furnace body 2 has a structure in which the furnace body 20 and the furnace bottom body 21 are connected to each other, and the furnace bottom body 21 is suspended from the furnace body 20.
If necessary, the furnace bottom body 21 is removed from a carriage (not shown) and moved to a predetermined place. By doing so, the repair of the furnace bottom 21 and the repair of the inside of the furnace main body 20 are facilitated.

A supply port 5 is provided at a substantially intermediate portion of the furnace body 2 in an elevational direction, and a pusher 6 is provided in connection with the supply port 5. The pusher 6 has a dust supply device 7 and a coke supply device. 8 are connected. Although not shown, the dust supply device 7 and the coke supply device 8 are provided with double butterflies so as to block invasion of outside air as much as possible. An exhaust gas port 9 is provided near the upper part of the furnace body 2, and the secondary combustion furnace 10, the primary cooling tower 11, the heat exchanger 12, the secondary cooling tower 13, and the dust collector 14 are connected to the exhaust gas port 9. Yes, dust collector 14
After that, an unillustrated induction fan and an exhaust tower are connected. The furnace bottom 2 of the furnace body 2 is provided with a molten slag discharge port 23 communicating with the inside of the furnace body 2.
5 and a slag cooling water tank 16 are provided.

Next, the furnace operation and operating conditions of the melting method of the present invention will be described. First, when the temperature rise of the furnace body 2 in a normal temperature state is started, the furnace bottom 22 is filled with coke and the coke layer 2 is filled.
Then, the plasma torch 1 is ignited and hot air at about 1800 ° C. is blown toward the coke layer 25. The furnace bottom 22 and the coke layer 25 are formed by the plasma torch 1
About three hours after the combustion of the hot air and coke
The temperature is raised to about 500 ° C. The dust is supplied from the dust supply device 7 into the furnace body 2 by the pusher 6 and the mixture of coke and limestone is supplied from the coke supply device 8 by the pusher 6. In this embodiment, the weight ratio of coke to dust is 2%. When dust and coke are supplied, a dust layer 26 is formed on the coke layer 25 in which dust and coke are alternately formed in a substantially layered shape. In the present embodiment, the furnace body 2
The air to be supplied into the furnace is supplied from the plasma torch 1 and the first and second tuyeres 3, 4, and the total amount of air is equal to or less than the stoichiometric amount of air for combustible substances such as coke and dust in the furnace body 2. In practice, the ratio of the stoichiometric air amount to the total air amount was 1: 0.2 to 0.5.

The dust layer 26 deposited on the heated coke layer 25 is dried and a part thereof is burned by the combustion air, and the other part is gasified because the combustion air consumes the combustion air. The ash generated by the combustion of the refuse and the char generated by the gasification are melted by the hot air from the coke layer 25 heated to about 1500 ° C. to become molten slag, which flows down the coke layer 26 and accumulates in the furnace bottom 22.
The molten slag accumulated in the furnace bottom 22 is discharged from the furnace through a molten slag discharge port 23 provided in the furnace bottom. As described above, the supply of garbage and the supply of coke are performed at a ratio of 3: 1. Therefore, it is considered that the garbage and the coke form a layer substantially alternately, and the quantitative ratio is about 2%. Since combustion is much quicker than coke, most of the combustion air described above is consumed for the combustion of dust, and coke is difficult to burn, and consequently coke is less consumed.
As a result, the upper part of the garbage layer 26 is a zone 26 where the garbage is rich.
1 and the garbage layer 2 where garbage combustion and gasification progress
A zone 262 where dust and coke coexist is formed in the middle of the zone 6, and a zone 263 where almost all coke is formed below the dust layer 26. As a result, the coke layer 25 is continuously formed at a predetermined height in the furnace bottom 22, and the level of the coke layer 25 is maintained when the consumption amount and the supply amount of coke are balanced. is there.

In the present embodiment, an example is shown in which the dust supply port 5 is provided substantially in the middle of the furnace body 1, but the invention is not limited to this. For example, the dust supply port 5 is provided near the furnace top of the furnace body 1. You may.

Next, an embodiment in which refuse is melted by using the melting method of the present invention will be described. (Example 1) The properties of garbage used in this example are shown below. Waste type: General waste (mainly household waste) Moisture content: 46.5% Lower heating value: 8200 KJ / Kg Ash content: 7.9% The above-mentioned garbage was melted under the following conditions. Power supply amount to plasma torch: 360 MJ / hr Coke supply amount: 30 Kg / hr Waste supply amount: 1000 Kg / hr Total air amount: 700 Nm ³ / hr Air amount from plasma torch: 150 Nm ³ / h
r The test was performed under the above conditions, but the hot air temperature from the plasma torch was about 1800 ° C., the ambient temperature of the coke layer 25 at the furnace bottom was 1500 ° C., and the pressure at the furnace bottom 22 was average. At a positive pressure of 1.5 KPa.

The temperature of each part in the furnace body 2 was approximately constant at about 1500 ° C. in the coke layer, and was 500 to 900 ° C. in the space above the dust layer 26. Since the garbage is supplied in batches of once / one minute, the temperature is lowered at the moment when it is supplied, because the water in the garbage evaporates and the temperature is reduced. It is.

When refuse and coke are supplied to this furnace to burn and gasify, the following process is performed. Since the upper part of the deposited dust layer has just been supplied, it is a dust-rich part in which the amount of coke in the dust is small. The garbage burns or gasifies in the lower part from there, and the amount decreases rapidly.However, the amount of coke in the garbage is less than the amount of coke in the garbage because it is harder to burn and the amount of the coke is harder to reduce than the garbage. It becomes a mixed part that gradually becomes larger. Furthermore, in the lower part, the refuse is burned or gasified and turned into ash or char, but a large amount of coke still remains, and this becomes a coke-rich part (coke layer). The ash that has reached the coke layer has a high temperature of about 1500 ° C. and is melted to form molten slag, which flows down the coke layer and accumulates at the bottom of the furnace, and is sequentially discharged out of the furnace through an outlet. Since the coke layer is a packed bed with a large number of gaps, the molten slag easily flows down between them, and does not solidify partly because it is evenly exposed to the hot air while it is stored in the furnace bottom. In addition, since the hot air of the plasma torch is blown toward the lower layer of the coke layer, the entire coke layer can be uniformly maintained at a high temperature of about 1500 ° C, and the molten slag can be maintained in a stable molten state. Can be.

In this embodiment, the blowing pressure of the shroud air blown from the plasma torch is set to 14.7 KPa. However, the pressure near the furnace bottom 22 becomes about 1.5 KPa due to the ventilation resistance of the coke layer 25 and the dust layer 26 described above. And acts as a pressure difference sufficient to extrude the molten slag from the furnace bottom 22. However, even if the liquid level of the molten slag drops and hot air blows out in the furnace, the momentum is weak and does not cause danger. Furnace bottom 2 as described above
The low furnace pressure near 2 enables continuous discharge of molten slag.

(Embodiment 2) In this embodiment, the lower heating value of the garbage of Embodiment 1 is reduced, and the amount of electric power supplied to the plasma torch is increased. The properties of the garbage used in this example are shown below. Garbage type: General waste (mainly household waste) Moisture content: 71.3% Lower heating value: 3400 KJ / Kg Ash content: 14.2% The above-mentioned garbage was melted under the following conditions. Electric power supply to the plasma torch: 790 MJ / hr and other conditions (coke supply, dust supply,
The amount of air, etc.) is the same as in the first embodiment. Also in this example, similarly to Example 1, the molten slag could be kept in a stable molten state, and the continuous discharge of the molten slag was favorably performed.

(Embodiment 3) In this embodiment, the lower heating value of the garbage of Embodiment 1 is increased, and the amount of power supplied to the plasma torch is reduced. The properties of the garbage used in this example are shown below. Dust type: General waste (mainly household waste) Water content: 30.1% Lower heating value: 12000 KJ / Kg Ash content: 3.5% The above-mentioned garbage was melted under the following conditions. Electric power supply to the plasma torch: 290 MJ / hr and other conditions (coke supply, refuse supply,
The amount of air, etc.) is the same as in the first embodiment. Also in this example, similarly to Example 1, the molten slag could be kept in a stable molten state, and the continuous discharge of the molten slag was favorably performed.

(Embodiment 4) In this embodiment, the amount of coke supplied to dust within a range where the fluctuation of the lower heating value is high is smaller than that of the above-mentioned Embodiments 1 to 3. . The properties of the garbage used in this example are shown below. Garbage type: General waste (mainly household waste) Water content: 29.2% Lower heating value: 9800 KJ / Kg Ash content: 3.2% The above-mentioned garbage was melted under the following conditions. Electric power supply to the plasma torch: 330 MJ / hr Coke supply: 20 kg / hr And other conditions (dust supply, air amount, etc.) are the same as in the first embodiment. Also in this example, similarly to Example 1, the molten slag can be kept in a stable molten state,
Continuous discharge of molten slag was performed well.

(Embodiment 5) In this embodiment, the lower heating value of the garbage of Embodiment 4 is increased, and the amount of electric power supplied to the plasma torch is reduced. The properties of the garbage used in this example are shown below. Dust type: General waste (mainly household waste) Moisture content: 28.3% Lower heating value: 11,000 KJ / Kg Ash content: 2.9% The above-mentioned garbage was melted under the following conditions. Electric power supply to the plasma torch: 300 MJ / hr and other conditions (coke supply, dust supply,
The amount of air, etc.) is the same as in the fourth embodiment. Also in this example, similarly to Example 1, the molten slag could be kept in a stable molten state, and the continuous discharge of the molten slag was favorably performed.

(Embodiment 6) In this embodiment, the lower heating value of the garbage of Embodiment 5 is increased, and the amount of electric power supplied to the plasma torch is reduced. The properties of the garbage used in this example are shown below. Dust type: General waste (mainly household waste) Moisture content: 27.1% Low heating value: 12000 KJ / Kg Ash content: 2.5% The above-mentioned garbage was melted under the following conditions. Electric power supply to plasma torch: 260 MJ / hr and other conditions (coke supply, dust supply,
The amount of air, etc.) is the same as in the fourth embodiment. Also in this example, similarly to Example 1, the molten slag could be kept in a stable molten state, and the continuous discharge of the molten slag was favorably performed.

Comparative Example 1 In this comparative example, the amount of electric power supplied to the plasma torch of the first embodiment is reduced. The amount of power supplied to the plasma torch of this comparative example was 290 MJ /
hr. The rest is the same as the first embodiment.
When the refuse was melted under such conditions, the temperature of the coke layer changed from 1200 ° C. to 1280 ° C., which was lower than that of Example 1. For this reason, solidification of the molten slag occurred in the molten slag discharge port 23 and the slag gutter 15 connected thereto, which hindered the continuous discharge of the molten slag.

(Comparative Example 2) In this comparative example, the amount of power supplied to the plasma torch of the second embodiment is reduced. The amount of power supplied to the plasma torch of this comparative example was 600 MJ /
hr. Other than the above, it is the same as the second embodiment.
When the refuse was melted under such conditions, the temperature of the coke layer changed from 1230 ° C. to 1330 ° C., which was lower than that of Example 2. For this reason, solidification of the molten slag occurred in the molten slag discharge port 23 and the slag gutter 15 connected thereto, which hindered the continuous discharge of the molten slag.

Comparative Example 3 In this comparative example, the amount of electric power supplied to the plasma torch of the third embodiment is reduced. The amount of power supplied to the plasma torch of this comparative example was 210 MJ /
hr. The rest is the same as the third embodiment.
When the refuse was melted under such conditions, the temperature of the coke layer changed from 1200 ° C. to 1280 ° C., which was lower than that of Example 3. For this reason, solidification of the molten slag occurred in the molten slag discharge port 23 and the slag gutter 15 connected thereto, which hindered the continuous discharge of the molten slag.

Comparative Example 4 In this comparative example, the amount of electric power supplied to the plasma torch of the fourth embodiment is reduced. The amount of power supplied to the plasma torch of this comparative example was 280 MJ /
hr. The rest is the same as the fourth embodiment.
When the refuse was melted under such conditions, the temperature of the coke layer changed from 1220 ° C. to 1290 ° C., which was lower than that of Example 4. For this reason, solidification of the molten slag occurred in the molten slag discharge port 23 and the slag gutter 15 connected thereto, which hindered the continuous discharge of the molten slag.

Comparative Example 5 In this comparative example, the amount of electric power supplied to the plasma torch of the fifth embodiment is reduced. The amount of power supplied to the plasma torch of this comparative example was 590 MJ /
hr. Other than the above, it is the same as the fifth embodiment.
When the refuse was melted under such conditions, the temperature of the coke layer changed from 1200 ° C. to 1290 ° C., which was lower than that of Example 5. For this reason, solidification of the molten slag occurred in the molten slag discharge port 23 and the slag gutter 15 connected thereto, which hindered the continuous discharge of the molten slag.

Comparative Example 6 In this comparative example, the amount of electric power supplied to the plasma torch of Example 6 was reduced. The amount of power supplied to the plasma torch of this comparative example was 230 MJ /
hr. Other than the above, it is the same as the sixth embodiment.
When the refuse was melted under such conditions, the temperature of the coke layer changed from 1250 ° C. to 1330 ° C., which was lower than that of Example 6. For this reason, solidification of the molten slag occurred in the molten slag discharge port 23 and the slag gutter 15 connected thereto, which hindered the continuous discharge of the molten slag.

From the above Examples 1 to 3 and Comparative Examples 1 to 3, the following became clear. Within the normal fluctuation range of the low calorific value of garbage from general waste, 1000 kg of garbage
/ Hr melting process requires a coke feed rate of 30
In order to reduce the lower heat generation amount of dust as in the comparative example, the power supply amount to the plasma torch may be increased as in the embodiment. Conversely, this also means that the amount of power supplied to the plasma torch should be increased with respect to the decrease in the lower heat generation amount of the garbage.

From the above Examples 4 to 6 and Comparative Examples 4 to 6, the following became clear. Within the fluctuation range of the high value of the lower calorific value of the garbage of general waste, 1000 K
g / hr In order to carry out the melting treatment, the supply amount of coke is set to 20 kg / hr, and in order to reduce the lower heating value of the refuse as in the comparative example, the amount of electric power supplied to the plasma torch as in the embodiment is reduced. What is necessary is just to increase. Conversely, this also means that the amount of power supplied to the plasma torch should be increased with respect to the decrease in the lower heat generation amount of the garbage.

When the above Examples 1 to 3 and Comparative Examples 1 to 3 and Examples 4 to 6 and Comparative Examples 4 to 6 were considered together, the following became clear. Even in the case of Examples 1 to 3 and Comparative Examples 1 to 3, and in the case of Examples 4 to 6 and Comparative Examples 4 to 6, the amount of coke supplied was kept constant, and the plasma was controlled with respect to the increase or decrease in the lower heating value of the dust. This can be handled by adjusting the amount of power supplied to the torch. This means that short-term fluctuations in the lower heating value of the refuse can be dealt with by adjusting the amount of power supplied to the plasma torch while keeping the coke supply constant. As compared with Examples 1 to 3 and Comparative Examples 1 to 3, Examples 4 to 6 and Comparative Examples 4 to 6 have higher values of the lower heating value, as described in the section to be solved by the invention. `` For example, due to seasonal factors, there are long-term fluctuations such as a decrease in the lower heating value due to an increase in garbage in summer and an increase in the lower heating value due to an increase in plastic waste in the winter. '' Can be considered. Variations in Examples 4 to 6 and Comparative Examples 4 to 6 with respect to Examples 1 to 3 and Comparative Examples 1 to 3 are regarded as a long-term increase in the lower heating value. To cope with the increase, the coke supply amount may be reduced. Conversely, this means that the supply of coke may be increased with respect to a long-term decrease in the lower heating value. This means that long-term fluctuations in the lower heating value of the refuse can be dealt with by adjusting the coke supply. Summarizing the above, short-term fluctuations in the lower heating value of refuse can be dealt with by adjusting the amount of power supplied to the plasma torch while keeping the coke supply constant, and the lower heating value of the refuse. The long-term fluctuation of can be handled by adjusting the coke supply.

[0037]

According to the present invention, the amount of coke supplied can be minimized, and short-term fluctuations in the lower heating value of dust can be dealt with by adjusting the amount of power supplied to the plasma torch. For long-term fluctuations in the lower heating value, the supply of coke can be adjusted, so that the molten slag can be discharged continuously, while increasing the cost of melting and reducing the amount of garbage in the furnace. It is possible to provide a method for melting garbage, while preventing the emission of carbon dioxide.

[Brief description of the drawings]

FIG. 1 is a schematic view of a system relating to a method for melting garbage according to the present invention.

FIG. 2 is a cross-sectional view illustrating a method of melting garbage according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma torch, 2 Furnace main body, 3 1st tuyere, 4 2nd tuyere, 5 supply port, 7 dust supply apparatus, 8 coke supply apparatus, 9 exhaust gas port, 20 furnace body, 21 furnace bottom body, 22 Furnace bottom, 23 molten slag outlet, 25 coke layer, 26 dust layer.

 ──────────────────────────────────────────────────の Continued on the front page F term (reference) 3K061 AA16 AB03 AC01 BA04 CA08 CA14 DB04 DB16 3K062 AA16 AB03 AC01 BA02 DA36 DB12 DB14 4D004 AA46 AB03 AC04 CA27 CA29 CA43 DA02

Claims (4)

[Claims] A coke and dust are supplied into a shaft furnace, a coke layer is formed at a bottom of the furnace, and a plasma torch is provided so as to blow hot air toward the coke layer. Combustion and gasification of garbage in an atmosphere below the stoichiometric amount of air, a method for melting garbage in which the residue is discharged out of the furnace as a molten slag, wherein a change in the lower heating value of the garbage to the plasma torch A method for melting garbage, wherein the amount of supplied electric power is adjusted. 2. A coke and refuse are supplied into a shaft furnace, a coke layer is formed at a bottom of the furnace, and a plasma torch is provided so as to blow hot air toward the coke layer. A method for melting garbage, in which garbage is burned and gasified under an atmosphere equal to or less than the stoichiometric amount of air, and the residue is discharged out of the furnace as molten slag. A method of melting garbage, characterized by increasing the amount of power supplied to the plasma torch and reducing the amount of power supplied to the plasma torch for a short-term increase in the lower heating value of the garbage . 3. A coke and refuse are supplied into a shaft furnace, a coke layer is formed on a bottom of the furnace, and a plasma torch is provided so as to blow hot air toward the coke layer. A method for melting garbage in which the garbage is burned and gasified under an atmosphere equal to or less than the stoichiometric amount of air, and the residue is discharged out of the furnace as molten slag. The amount of coke supplied into the shaft furnace is increased, and the amount of coke supplied into the shaft furnace is reduced with respect to a long-term increase in the lower heating value of dust. How to melt garbage. 4. A coke layer and a refuse are supplied into a shaft furnace, a coke layer is formed on a bottom of the furnace, and a plasma torch is provided so as to blow hot air toward the coke layer. A method for melting garbage, in which garbage is burned and gasified under an atmosphere equal to or less than the stoichiometric amount of air, and the residue is discharged out of the furnace as molten slag. The amount of power supplied to the plasma torch is increased, and for a short-term increase in the lower heating value of the dust, the amount of power supplied to the plasma torch is reduced, and the lower heating value of the dust is prolonged. For a significant decrease, the amount of coke supplied to the shaft furnace is increased, and for a long-term increase in the lower heating value of the dust, the amount of coke supplied to the shaft furnace is reduced. Like A method for melting garbage, characterized in that: