JP2001280621A - Melting processing method for refuse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the difficulty with the prior art that provided intermittent operation is performed in a melting processing furnace for refuse, cokes on a bottom of the furnace is covered with a solidified cold slag each time the operation is started so that the coke is unlikely to be fired, further long time is required until the furnace outputs cast stably to sharply deteriorate the operation rate of the furnace, and hence it is needed to design a larger processing capability of the furnace. SOLUTION: There are repeated a refuse melting processing wherein refuse and coke are supplied into a shaft furnace, and the refuse is combusted and gasified in the atmosphere less than a stoichiometric air amount with respect to combustible substances in the refuse, and further residues are discharged from a cast outlet as molten slag with the aid of hot air supplied from a plasma torch, and a processing of interrupting the supply of the refuse and coke to temporarily interrupt the refuse melting processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refuse melting furnace in which refuse is burned and gasified in a furnace, and the remaining ash and char are melted in the same furnace to form molten slag and discharged outside the furnace.

[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 of converting garbage into molten slag in one furnace, for example, Japanese Patent Publication No. 56-2243 (prior art-1) and Japanese Patent Publication No. 60-11766 (prior art-
2), JP-A-2-298717 (prior art-
3), JP-A-4-124515 (prior art-4)
There is one described in. The melting furnaces described in the prior arts 1 and 2 use combustion of coke and dust as a heating source and supply oxygen-enriched air to burn the same, and the molten slag is discharged intermittently. It is. The melting furnace described in Prior Art-3 uses combustion of coke and hot air from a plasma torch as a heating source. Prior art-4 uses coke combustion and hot air from a plasma torch as a heating source.

[0004]

However, in the prior arts 1 and 2 among the above-mentioned prior arts, a separate device for producing oxygen-enriched air is required, and in order to discharge the molten slag intermittently. There is a problem that it is necessary to open and close the discharge port. Prior art 3,
In No. 4, a plasma torch is used, but a tuyere for blowing air for burning dust and the like is not separately provided, so that the combustion heat of the dust can hardly be used. There is a problem that an auxiliary heat source such as electric power increases.

[0005] On the other hand, incinerators or melting furnaces are generally operated continuously without stopping the operation of the furnace as much as possible in order to increase the operating rate and the thermal efficiency, and are operated only when necessary, such as furnace inspection and repair of the furnace wall. To stop. Such continuous operation is on Saturday,
There is a problem that the driving operator must work on holidays such as Sundays and public holidays, which causes an increase in operation and management costs. When the operation of the furnace is stopped on a holiday, for example, if the furnace is stopped on Saturday and Sunday, the furnace must be started every week.
Since the coke at the bottom of the furnace is covered with the cooled and solidified slag, it is difficult to ignite the coke, and a long time is required until the furnace can stably slag, and the operating rate of the furnace is greatly reduced. As a result, it is necessary to design the processing capacity of the furnace in advance. The present invention solves the above-described problems, and enables continuous discharge of molten slag,
It is another object of the present invention to provide a method for melting and processing garbage, which requires a small amount of auxiliary heat source added from outside. An object of the present invention is to solve the above-described problems and to provide a method for melting and processing garbage, which can minimize a decrease in the processing capacity of a furnace even when an intermittent operation is performed by shortening a rise time. I do.

[0006]

SUMMARY OF THE INVENTION According to the present invention, dust and coke are supplied into a shaft furnace, and the dust is burned and gasified in an atmosphere having a stoichiometric amount of air less than that of combustible substances, and the residue is converted into plasma. It is characterized by repeating the process of melting garbage discharged from the slag port as molten slag by hot air supplied from the torch, and temporarily stopping the garbage melting process by stopping the supply of garbage and coke. This is a method of melting waste. In the present invention, it is preferable that a tuyere is provided above the plasma torch, and air is blown toward dust in the furnace during the melting process of dust. In the present invention, it is preferable that the pressure in the vicinity of the furnace bottom is maintained at an average of a positive pressure of 0.3 to 5 KPa by adjusting the amount of air supplied from a plasma torch and / or a tuyere at the time of refuse melting processing. The present invention is characterized in that molten slag is continuously discharged from a molten slag discharge port provided in a furnace bottom.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When dust and coke are supplied to this furnace for combustion and gasification, the following steps are 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. 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 25 is melted into molten slag because it is at a high temperature of about 1500 ° C., and flows down through the coke layer 25 to form the furnace bottom 2.
2 and is discharged from the molten slag discharge port 23 to the outside of the furnace. Since the coke layer 25 is a packed layer having a large number of gaps, the molten slag easily flows down between the layers and the furnace bottom 2
Even during the accumulation in the second coke layer 2, the coke layer 25 is evenly exposed to the stored coke layer 25, so that it is not partially cooled. Further, since the hot air of the plasma torch 1 is blown toward the lower part of the coke layer 25 near the molten slag discharge port 23, the coke layer and the furnace bottom around the molten slag discharge port 23 and the molten slag are also blown. High temperature can be stably maintained, and stable and continuous discharge of molten slag can be maintained. Therefore, the present invention is particularly effective for a small-sized melting furnace that has a small amount of waste treatment, a small amount of molten slag flowing out, and is easily solidified.

In the refuse melting furnace used in the present invention, a coke layer is formed at the bottom of a shaft furnace, the coke layer is heated by hot air blown from a plasma torch, and a part of the coke layer is burned. The dust accumulated on the coke layer is burned and gasified in an atmosphere with a stoichiometric amount of air or less by heat, and the resulting ash is melted and converted into slag in the coke layer and discharged out of the furnace. Things. 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.

The melting furnace used in the present invention blows hot air of a plasma torch 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 reaches a temperature of 1000 to 2500 ° C., which heats the coke layer and burns a part of the coke layer with the oxygen in the hot air.
It can be stably maintained at 0 ° C. In order to maintain the temperature of the coke layer at 1500 ° C., for example, only by the combustion heat of coke, oxygen-rich air is required to maintain the temperature. However, in the melting furnace used in the present invention, a plasma torch is used. Since it is used, the hot air may be ordinary air.

As described above, in the melting furnace of the present invention, the heat input in the heat balance in the furnace is covered by the heat of the plasma torch, the heat of combustion of waste, and the heat of combustion of coke. It is safe to use nitrogen instead of air as the hot air source for the torch. At that time, the combustion of coke naturally becomes smaller than that of air, and the heat input also decreases. Therefore, it is necessary to increase the output of the plasma torch in order to compensate for this.

The blow pressure of the plasma air and shroud air of the plasma torch is set to a positive pressure of 10 to 30 KPa, and the flow rate of the air supplied from the tuyere and the ventilation resistance of the dust layer / coke layer are adjusted to adjust the coke layer. A certain pressure near the furnace bottom 22 can be set to a positive pressure of 0.3 to 5 KPa. When the pressure near the bottom of the furnace exceeds 5 KPa, the molten slag discharge port is connected to
Hot air is strongly blown out, which disadvantageously brings a large amount of heat inside the furnace to the outside of the furnace, and may cause burns to persons working around the furnace.
Further, when the pressure in the vicinity of the furnace bottom is lower than 0.3 KPa, the force for pushing out the molten slag generated by the pressure difference from the outside air becomes small, and it becomes difficult to discharge the molten slag. In addition, the outside air is sucked, the temperature around the molten slag discharge port is reduced, and the molten slag is easily solidified.

Since the melting furnace used in the present invention uses a plasma torch for the shaft furnace, the furnace has an extremely rugged structure with no movable bodies, and the plasma torch is excellent in operability, and therefore, is difficult to operate. The furnace can be easily operated. Also,
Because the furnace bottom is separable, 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 very easily. .

Next, an embodiment of a method for melting and processing garbage according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a refuse melting furnace system according to the present invention, and FIG. 2 is a sectional view showing a refuse melting furnace used in the present invention. 1 and 2, reference numeral 2 denotes a furnace body, a plasma torch 1 near the furnace bottom, and a first tuyere 3 above the plasma torch 1.
And a second tuyere 4 are provided. In this embodiment, the plasma torch 1 is provided at two places on the circumference of the same height of the furnace body, 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 are also on the circumference 6
There were two places. 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. Furnace body 2 is outer shell 2
01, a refractory material 202 is applied inside. 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. And move it to the designated place. By doing so, the furnace bottom 2
1 and the repair of the inside of the furnace main body 20 were completed.

A supply port 5 is provided in 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 butterfly valves so as to block the invasion of the outside air as much as possible. An exhaust gas port 9 is provided near the upper portion of the furnace body 2, and is connected to the exhaust gas port 9 so as to be connected to the secondary combustion furnace 10, the primary cooling tower 11, and the heat exchanger 1.
2. The secondary cooling tower 13 and the dust collector 14 are connected, and after the dust collector 14, an induction fan and an exhaust tower (not shown) 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, and a slag gutter 15 and a slag cooling water tank 16 are provided in connection therewith.

Next, the operation and operating conditions of the melting furnace used in the present invention will be described. First, when starting to raise the temperature of the furnace body 2 in a normal temperature state, coke is filled in the furnace bottom portion 22 to form a coke layer 25, and then the plasma torch 1 is ignited and hot air of about 1800 ° C. is supplied to the coke layer 25. Blow toward. The furnace bottom 22 and the coke layer 25 are heated to about 1500 ° C. after about 3 hours by the hot air of the plasma torch 1 and the heat of combustion of the coke. 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 air supplied into the furnace body 2 includes the plasma torch 1 and the first,
The total amount of air supplied from the second tuyeres 3 and 4 is less than the stoichiometric amount of air for combustible substances such as coke and refuse in the furnace body 2 and the oxygen ratio is 0.1 to 0.7. Range is desirable. Oxygen ratio = (supplied oxygen amount + organic oxygen amount in dust) / ((C
× 32/12) + (H × 16/2)) Here, the supplied oxygen amount is the oxygen amount (kg / hr) supplied from the plasma torch and the tuyere, and C is combined with the oxygen and the organic oxygen in the dust. The total of the amount of carbon in the dust and coke containing organic compounds in the furnace (kg / hr), H is the amount of hydrogen in the dust and coke containing organic compounds in the furnace combined with the oxygen and the organic oxygen in the dust. Total (kg / hr). However, when the garbage contains a halogen element, the halogen element is combined with hydrogen, so the amount of hydrogen is excluded.

The garbage layer 26 deposited on the heated coke layer 25 is dried, a part of which is burned by the combustion air, and another 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, flow down in the coke layer 26 and accumulate 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, since the supply of garbage and the supply of coke are performed at a ratio of 3: 1, it is considered that the garbage and the coke are substantially alternately layered, and the quantitative ratio is about 2% by weight. Since the combustion of ash is much faster than that of coke, most of the combustion air is consumed for the combustion of the refuse, and the coke is hardly burned, so that the consumption of the coke is small. As a result, the upper part of the dust layer 26 becomes a zone 261 where dust is rich, and the middle part of the dust layer 26 in which the burning and gasification of dust progresses becomes a zone 262 in which dust and coke are mixed. Zone 263. 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 melting furnace used in the present invention, the heat input in the heat balance in the furnace is covered by the calorific value of the plasma torch, the calorific value of the combustion of dust, and the caloric value of the coke combustion. It is safe to use nitrogen instead of air. However, at that time, since the combustion of coke is suppressed and the heat input is reduced, it is necessary to increase the output of the plasma torch in order to compensate for it.

(Example 1) By using the apparatus shown in FIGS. 1 and 2, refuse was treated continuously for 30 days under the following conditions. The properties of the garbage used in this example are shown below. -Type of garbage: General waste (mainly household garbage)-Moisture content: 55%-Lower heating value: 358KJ / Kg-Ash content: 8% The garbage having the above properties was melted under the following conditions.・ Dust supply amount: 1000 kg / hour ・ Coke supply amount: 20 kg / hour ・ Total air amount: 150 Nm ³ / hour (oxygen ratio:
0.15 No supply from tuyeres 3 and 4) ・ Amount of air from plasma torch: 150 Nm ³ /
Time (oxygen ratio: 0.15) ・ Blow pressure from plasma torch: 15 KPa

Dust is introduced from the inlet 5 every one minute, and coke and limestone are introduced every three minutes. The height of the dust layer (zone 261 + zone 262) is about 1 m and the height of the coke layer (zone 263). The height is about 0.5 m, the temperature of the coke layer 25 is about 1500 ° C., and the temperature of the gasification zone (the space above the refuse layer and the pressure is slightly negative with respect to the atmosphere) is 500 to 500. Burned at 900 ° C. The gas in the gasification zone is burned at 1000 to 1200 ° C. by sending air in the secondary combustion furnace 10 (residence time about 2 seconds).
Dioxin is decomposed, cooled to about 600 ° C. in the primary cooling tower 11, rapidly cooled to 160 to 180 ° C. in the secondary cooling tower 13 to prevent resynthesis of dioxin, and released to the atmosphere via the dust collector 14. You. As a result of measuring the properties of the exhaust gas, the dust was 0.001 g / Nm ³ (the legally regulated value was 0.15 and the same applies hereinafter), and the SOx (K value) was 0.1.
026 (17.5), HCl 3 ppm (430), N
Ox is 142 ppm (250), CO is 3 ppm (10
0) and dioxin showed good results of 0.01 ng / Nm ³ (5).

The hot gas temperature from the plasma torch is about 1
800 ° 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 0.9 KPa as a positive pressure on average. Approximately 60 minutes after the start of the supply of the refuse, the molten slag started to be discharged from the molten slag discharge port 23, and thereafter, a stable continuous slag could be discharged. The average discharge of molten slag is about 80 per hour.
Kg. A dissolution test of this slag was performed, and it was confirmed that both the water-cooled slag and the air-cooled slag met the soil environmental standards.

After the refuse melting process was performed for 30 consecutive days, the supply of refuse and coke and all utilities such as a plasma torch were stopped, and the furnace was left for 5 days. On the following day, the supply of hot air from the plasma torch and the air from the tuyere and the supply of dust and coke were started, and the dust melting process was restarted. Approximately 60 minutes after the start of the supply of hot air with the plasma torch, molten slag began to be discharged from the molten slag discharge port, and thereafter, stable continuous slag could be discharged.

In this embodiment, the blowing pressure of the shroud air blown from the plasma torch is 15 KPa, but the pressure near the furnace bottom 22 becomes about 0.9 KPa due to the ventilation resistance of the coke layer 25 and the waste layer 26 described above. Was. Under this pressure, the molten slag was satisfactorily discharged, and had a sufficient action to extrude the molten slag from the furnace bottom 22 and to prevent outside air from being sucked from the molten slag discharge port. When the liquid level of the molten slag dropped, hot air in the furnace was blown out, but the force was weak and did not cause danger.

(Example 2) Tuyere ^3, 4 to 550 Nm ³
The experiment was performed in the same manner as in Example 1 except that the total air amount was set to 700 Nm ³ / hour (oxygen ratio: 0.7) by supplying air at a rate of 700 Nm ³ / hour. The position of the tuyere 4 is a zone 26 where dust is rich.
1 and the position of the tuyere 3 were below the zone 262 where dust and coke were mixed. As a result of measuring the properties of the exhaust gas, it was confirmed that the exhaust gas satisfied the legally regulated values as in Example 1.

The atmosphere temperature of the coke layer 25 at the bottom of the furnace is 1
The temperature was 500 ° C., and the pressure at the furnace bottom 22 was 1.5 KPa as a positive pressure on average. About 6 since we started supplying garbage
After the elapse of 0 minutes, the molten slag began to be discharged from the molten slag discharge port 23, and thereafter, stable continuous slag could be discharged. Discharge of molten slag was on average about 80 kg per hour. A dissolution test of this slag was performed, and it was confirmed that both the water-cooled slag and the air-cooled slag met the soil environmental standards.

After performing this dust melting treatment for 30 consecutive days, the supply of dust and coke and all utilities such as a plasma torch were stopped, and the furnace was left for 5 days. On the following day, the supply of hot air from the plasma torch and the air from the tuyere and the supply of dust and coke were started, and the dust melting process was restarted. Approximately 60 minutes after the start of the supply of hot air with the plasma torch, molten slag began to be discharged from the molten slag discharge port, and thereafter, stable continuous slag could be discharged.

In this embodiment, the blowing pressure of the shroud air blown from the plasma torch is 15 KPa, but the pressure near the furnace bottom 22 becomes about 1.5 KPa due to the ventilation resistance of the coke layer 25 and the waste layer 26 described above. Was. Under this pressure, the molten slag was satisfactorily discharged, and had a sufficient action to extrude the molten slag from the furnace bottom 22 and to prevent outside air from being sucked from the molten slag discharge port. When the liquid level of the molten slag dropped, hot air in the furnace was blown out, but the force was weak and did not cause danger.

Comparative Example 1 In the melting furnace of FIG. 2, a combustion burner was used for coke ignition instead of the plasma torch, and an air supply tuyere (not shown) was provided at the same height as the combustion burner. The garbage was melted. The properties of the garbage used are shown below. Dust type: General waste (mainly household waste) Moisture content: 55% Lower heating value: 358 KJ / Kg Ash content: 8% The above-mentioned garbage was melted under the following conditions. Waste supply amount: 1000 kg / hour Coke supply amount: 70 kg / hour Total air amount: 1000 Nm ³ / hour (oxygen ratio:
0.7 Supply from tuyeres 3, 4 and the above-mentioned tuyeres) Air volume from combustion burner: 1500 Nm ³ / hour The output of the burner was almost equal to the output of the plasma torch. The test was carried out under the above-mentioned conditions. At this time, the atmosphere temperature of the coke layer 25 at the furnace bottom was 1500 ° C., and the pressure at the furnace bottom 22 was 5.5 KPa as a positive pressure on average.

The temperature of each part in the furnace body 2 was substantially 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.
After confirming that molten slag had started to be discharged from the molten slag discharge port, the slag port was closed and the burner was stopped. Thereafter, it was repeated that the slag opening was opened every two hours, and the slag opening was closed again. Discharge of molten slag was on average about 80 kg per hour.

After performing the refuse melting treatment for 30 consecutive days, the supply of refuse and coke and all utilities such as burners were stopped, and the furnace was left for 5 days. On the following day, the supply of hot air from the burner and the air from the tuyere and the supply of dust and coke were started, and the dust melting process was restarted. Since a large amount of gas was supplied into the furnace, a large amount of heat was taken out of the coke layer, so that about 120 minutes after the start of the supply of hot air with the burner, molten slag began to emerge from the molten slag discharge port.

[0030]

As described above, the refuse melting method of the present invention has the above-mentioned structure, so that the molten slag can be continuously discharged and the number of auxiliary heat sources added from the outside can be reduced. Since the refuse melting method of the present invention is configured as described above, the rise time can be shortened, so that a decrease in the processing capacity of the furnace can be minimized even when the intermittent operation is performed. Therefore, the decrease in the processing capacity due to the intermittent operation may be considered only for the time when the operation of the furnace is stopped, and there is almost no need to consider the rise time. The refuse melting method of the present invention has a relatively small amount of waste (for example, 1
It is particularly suitable when the municipality performs garbage melting processing.

[Brief description of the drawings]

FIG. 1 is a schematic view of a system related to a refuse melting furnace used in the present invention.

FIG. 2 is a sectional view showing a refuse melting furnace used in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Plasma torch, 2 Furnace body, 3,4 tuyere, 5 supply port, 7 Dust supply device, 8 Coke supply device, 9
Exhaust gas outlet, 20 furnace body, 21 furnace bottom, 22 furnace bottom, 23 molten slag outlet, 25 coke layer, 26
Garbage layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F27B 1/16 F27D 3/14 Z F27D 3/14 11/08 E 11/08 B09B 3/00 303K (72 ) Inventor Hiroyuki Hagiwara 6010, Mitsugashiri, Kumagaya-shi, Saitama F-term in Hitachi Metals Co., Ltd. Production System Research Laboratories FK (Reference) GB03 GB12 GD08 4K055 AA01 AA03 JA00 4K063 AA04 AA12 BA13 CA02 CA06 FA56

Claims (4)

[Claims] 1. Dust and coke are supplied into a shaft furnace, and the refuse is burned and gasified in an atmosphere having a stoichiometric amount of air or less relative to those combustible substances, and the residue is heated by hot air supplied from a plasma torch. A method for melting garbage, comprising repeatedly performing a process of melting garbage discharged from a slag port as molten slag and a process of temporarily stopping the supply of garbage and coke to temporarily stop the melting of garbage. 2. The method of claim 1, wherein a tuyere is provided above the plasma torch, and air is blown toward the dust in the furnace when the dust is melted. 3. The method for melting garbage according to claim 1, wherein the pressure near the furnace bottom is maintained at an average of a positive pressure of 0.3 to 5 KPa during the melting processing of the garbage. 4. The molten slag is continuously discharged from a molten slag discharge port provided at a furnace bottom.
4. The method for melting waste according to any one of claims 1 to 3.