JP2003075068A - Vertical melting furnace, air feed method to the melting furnace, and operation method for the melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical melting furnace capable of producing and discharging a molten substance without stagnation by increasing the amounts of consumption of a fuel such as cokes and oxygen without successively raising the temperature in the vicinity of a twyer, and provide an air feed method to the vertical melting furnace, and an operation method for the vertical melting furnace. SOLUTION: In a vertical melting furnace in which a high temperature combustion zone 61 is formed at a lower portion in the furnace for melting a substance deposited in the furnace, a flow passage at a twyer 16 for blowing oxygen containing gas into the high temperature combustion zone 61 is divided into inside and outside passages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical melting furnace in which a high temperature combustion zone for melting an object to be processed deposited in the furnace is formed in the lower part of the furnace, a method for blowing air to the vertical melting furnace, and The present invention relates to a method for operating the vertical melting furnace.

[0002]

2. Description of the Related Art In a vertical type metal smelting furnace, a waste melting furnace, etc., materials to be treated such as raw materials and waste and fuel such as coke are charged from the top of the furnace and deposited in the furnace. The deposited charge gradually descends while being heated, and reaches the lower part of the furnace to generate a molten material such as molten metal or molten slag. The generated melt is discharged outside the furnace through a discharge port provided at the bottom of the furnace.

A tuyere for blowing an oxygen-containing gas for burning a fuel such as coke is provided on the side of the lower part of the melting furnace, and a high temperature combustion zone is formed in the furnace in front of the tuyere. It When the object to be processed is waste, combustible components in the waste are also burned. When blowing the oxygen-containing gas from the tuyere, depending on the type of workpiece and operating conditions,
Air, oxygen-enriched air, or oxygen is blown. These gases may be heated if desired.

As one of the vertical melting furnaces, Japanese Patent Laid-Open No. 9-60
There is a waste gasification and melting furnace shown in Japanese Patent No. 830. In this melting furnace, tuyere is provided at the lower part of the furnace for blowing the oxygen-containing gas. Charged waste and fuel such as coke form a sedimentary layer, and a high-temperature combustion zone is formed in the furnace in front of the tuyere, and the ash and incombustibles in the waste are melted by this combustion heat. . The melt accumulates at the bottom of the furnace and is discharged continuously or intermittently.

[0005]

In the above prior art, the melt may not be smoothly discharged from the bottom of the furnace. The defective discharge of the melt occurs due to the following reasons.

In the high temperature combustion zone in the lower part of the furnace, coke and the like are best combusted near the tuyere by the oxygen-containing gas blown from the tuyere, and the oxygen-containing gas is consumed from the side of the furnace toward the center of the furnace. , The degree of combustion decreases. Therefore, the region near the tuyere has the highest temperature, and the temperature tends to decrease from the side of the furnace toward the center of the furnace. Since the temperature distribution in the high temperature combustion zone is as described above, if there is a change in the composition of the object to be treated,
The melting point of the object to be treated becomes high and the object to be treated in the central part of the furnace is not melted, or the viscosity of the molten material becomes high, and the discharge of the molten material is delayed in the central part of the furnace where the temperature is relatively low. May occur.

Particularly, in a waste melting furnace for treating waste such as municipal waste, since a large amount of SiO ₂ is contained in the waste, a treatment for reducing the viscosity of molten slag produced by adding limestone or the like. However, the viscosity of the molten slag generated due to fluctuations in the components of the waste increases, and the above-mentioned defective situations often appear.

Conventionally, when the above-mentioned defective state occurs, measures such as increasing the amount of fuel such as coke, increasing the oxygen concentration of the oxygen-containing gas blown from the tuyere, or increasing the temperature are taken. Then, the temperature of the entire high temperature combustion zone is raised so that the object to be treated in the central part of the furnace is melted smoothly and the viscosity of the melt is lowered to be discharged smoothly.

However, when the above measures are taken, there is a problem that the consumption of fuel such as coke and oxygen increases and the operating cost increases. Also, since the temperature of the central part of the furnace is raised, the temperature of the entire high temperature combustion zone is raised, so the temperature near the tuyere becomes even higher, and the furnace wall near where the tuyere is installed exceeds the heat resistance limit temperature. , There is a problem that will be damaged.

The present invention solves the above problems, increases the consumption of fuel such as coke and oxygen, and retains the object to be treated without raising the temperature of the high temperature combustion zone near the tuyere excessively. An object of the present invention is to provide a vertical melting furnace that can be melted and discharged without any need, a method for blowing air into the vertical melting furnace, and a method for operating the vertical melting furnace.

[0011]

In order to solve the above-mentioned problems, the vertical melting furnace according to the invention of claim 1 has a high-temperature combustion zone for melting the object to be treated deposited in the furnace. The vertical melting furnace formed in the lower part is characterized in that the tuyere's flow path for blowing the oxygen-containing gas to the high-temperature combustion zone is divided into two inside and outside.

A blowing method according to a second aspect of the present invention is the method for blowing a high temperature combustion zone in a vertical melting furnace according to the first aspect of the invention, wherein the flow rate of the oxygen-containing gas blown from the inner flow passage is changed to the outer flow passage. It is characterized in that the air is blown at a speed higher than the flow velocity of the oxygen-containing gas blown from.

A blowing method according to a third aspect of the present invention is the method for blowing a high temperature combustion zone in a vertical melting furnace according to the first aspect of the present invention, wherein the oxygen concentration of the oxygen-containing gas blown from the inner flow passage is changed to the outside flow rate. The feature is that the air is blown at a higher concentration than the oxygen-containing gas blown from the passage.

According to a fourth aspect of the invention, there is provided a method for blowing air to a high temperature combustion zone in a vertical melting furnace according to the first aspect of the invention, wherein the gas blown from the inner flow passage is oxygen and the outer flow passage is oxygen. The feature is that the gas blown from is air.

A blower method according to a fifth aspect of the present invention is the blower method according to the first aspect of the invention, in which the flow velocity of oxygen blown from the inner flow passage is made higher than the flow velocity of air blown from the outer flow passage. It is characterized by that.

A vertical melting furnace operating method according to a sixth aspect of the present invention is the vertical melting furnace operating method according to the first aspect of the present invention, in which the air is normally blown from the inner flow passage and the outer flow passage under the same conditions. When the discharge amount of the melt is reduced, the method is changed to any one or more of the blowing methods described in claims 2 to 5.

The tuyere provided in the vertical melting furnace of the present invention is utilized to restore the normal discharge of the melt when the discharge of the melt from the melt discharge port is delayed.

The tuyere provided in the vertical melting furnace of the present invention has two passages, and the blowing conditions of the oxygen-containing gas in the inner passage and the outer passage can be changed for each passage. As a result, when the discharge of the melt from the melt discharge port becomes delayed, the total amount of the blown air is kept constant by changing the conditions of the blown air from the two flow paths, and the melt is smoothly discharged. Can be generated and discharged.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on the embodiments. As an embodiment, a vertical waste melting furnace was taken up.

FIG. 1 is a diagram showing an example of an embodiment relating to the structure of a vertical waste melting furnace of the present invention. Reference numeral 10 denotes a vertical waste melting furnace in which the waste charged from the top of the furnace and the charge such as coke and limestone are deposited in the lower part 12 of the furnace and are sequentially melted. In the figure, 13 is an inlet for waste and coke, limestone, etc., 14 is an outlet for generated gas, and 15 is an outlet for melt. The upper part is the freeboard section 11. In addition, reference numeral 60 indicates a deposited charge.

A plurality of tuyere 16 for blowing the oxygen-containing gas are provided on the side of the lower part of the furnace 12 near the bottom of the furnace. The tuyere 16 has a structure shown in FIG. 2 which will be described later, and two flow paths for blowing the oxygen-containing gas are formed, so that the oxygen-containing gas is blown from the two flow paths. Has become. By blowing the oxygen-containing gas from the tuyere 16, combustible components in the coke and the waste are burned, and a high temperature combustion zone 61 is formed in the furnace. The charge 60 deposited in the furnace is heated by the high temperature gas generated in the high temperature combustion zone and is thermally decomposed. Ash and incombustibles in the waste are melted in the high temperature combustion zone, and the generated melt is discharged from the melt discharge port 15. 17 is the deposited charge 6
It is a secondary tuyere that blows an oxygen-containing gas for partially burning 0.

FIG. 2 is a schematic sectional view showing an example of tuyere provided in the vertical melting furnace according to the present invention. The tuyere is designed to blow the oxygen-containing gas supplied from the two systems into the furnace through separate flow passages.
And a cooling unit 32 provided on the outer circumference of the outer cylinder 31.
The cooling unit 32 has a water cooling structure. And the inner cylinder 30
The inside is a flow passage 33, and the space between the inner cylinder 30 and the outer cylinder 31 is an outer flow passage 34. In the figure, 35 is an inner oxygen-containing gas inlet, 36 is an outer oxygen-containing gas inlet, 37 is an inner oxygen-containing gas outlet, 38 is an outer oxygen-containing gas outlet, and 39 is cooling water. The inlet 40 is a cooling water outlet. In addition, the tuyere in the present invention is installed so that the tip is located at a position that coincides with the inner surface of the furnace inner wall of the vertical melting furnace, or the tip is slightly projected into the furnace.

Since the tuyere of the present invention is formed with two channels for blowing the oxygen-containing gas, the oxygen-containing gas can be blown from the two channels under different conditions. During normal times when the conditions inside the furnace are stable, air is blown to the inner and outer flow paths under the same conditions. Then, when the discharge of the melt from the melt discharge port becomes delayed, the combustion condition of the high temperature combustion zone is improved by changing the blowing conditions of the oxygen-containing gas from the above two flow paths. It is possible to ensure that the product is discharged smoothly.

For example, by adjusting the flow rate of the oxygen-containing gas blown from the inner flow path 33 and the outer flow path 34, the flow rate of the oxygen-containing gas blown from the inner flow path 33 is changed to the oxygen-containing gas blown from the outer flow path 34. The air is blown at a speed higher than that of the gas. As a result, the oxygen-containing gas blown from the inner flow path 33 can be sent to the central portion of the furnace and burned as compared with the normal time. Even if the total flow rate of the oxygen-containing gas to be blown is not increased, the combustion in the central part of the furnace is promoted to raise the temperature, and the ash content and the incombustible content in the waste are smoothly melted. It is possible to reduce the viscosity and stabilize the discharge from the melt discharge port.

Further, the oxygen concentration of the oxygen-containing gas blown from the inner channel 33 and the outer channel 34 can be changed. That is, the oxygen concentration of the oxygen-containing gas blown from the inner flow path 33 is made higher than the oxygen concentration of the oxygen-containing gas blown from the outer flow path 34 to blow the air, thereby promoting combustion in the central part of the furnace and generating waste. The ash content and the incombustible content in the melt can be smoothly melted, the viscosity of the melt can be reduced, and the discharge from the melt discharge port can be stabilized.

When changing the oxygen concentration of the oxygen-containing gas blown from the inner flow path 33 and the outer flow path 34, if oxygen is blown from the inner flow path 33 and air is blown from the outer flow path 34,
To further promote combustion in the central part of the furnace to smoothly melt ash and incombustibles in waste, and to lower the viscosity of the melt to stabilize discharge from the melt discharge port. You can

Further, the flow rate of air blown to each flow path is adjusted so that the flow velocity of oxygen blown from the inner flow path 33 is controlled by the outer flow path 3.
The air is blown at a velocity higher than that of the air blown from 4. As a result, the combustion in the central part of the furnace can be promoted and the temperature can be raised further, the ash content and the incombustible content in the waste can be smoothly melted, and the viscosity of the melt can be reduced to remove the melt. The discharge from the outlet can be stabilized.

FIG. 3 is a diagram for explaining an example of a method for blowing air to the vertical melting furnace of the present invention. In the figure, 10 is a vertical melting furnace, 1
Reference numeral 6 is a tuyere having two air flow passages including an inner flow passage and an outer flow passage, and 15 is a melt discharge port. Further, 53 and 54 are headers for distributing the supplied oxygen-containing gas to a plurality of tuyere, 53 is for supplying to the oxygen-containing gas introduction port 35 on the inner side, and 54 is an oxygen-containing gas introduction port on the outer side. It is for supplying to. The blown gases are air and oxygen. The air is divided into two systems, an inner channel and an outer channel of the tuyere, and each of the divided systems is provided with flow rate controllers 50a and 50b each including a flow meter and a flow rate adjusting valve.
Oxygen is also divided into two systems, an inner flow path and an outer flow path, and each of the divided systems has flow controllers 51a, 51, respectively.
b is installed. These four flow controllers can be adjusted independently, but the air flow velocity of the inner and outer flow passages is changed, the oxygen concentration of the oxygen-containing gas supplied to the inner and outer flow passages is changed, or the flow velocity and the oxygen concentration are changed. The setting of each flow rate controller relating to both changes is performed by the control device 52 in a unified manner.

When the discharge state of the melt from the melt discharge port 15 is monitored and it is detected that the discharge is delayed, the controller 52 changes the setting of each flow controller so as to improve the condition inside the furnace. .

In the embodiments described with reference to FIGS. 1 to 3, a vertical waste melting furnace is taken as the vertical melting furnace, but the present invention is not limited to the waste melting furnace. Instead, it is also applied to a melting furnace such as a scrap melting furnace or a cupola in which a high-temperature combustion zone for melting an object to be processed deposited in the furnace is formed.

Next, the result of the operation of melting the domestic refuse by the vertical type waste melting furnace having the structure shown in FIG. 1 will be described.

(Example 1) The melting furnace was a furnace having an inner diameter of 1.4 m at the lower part of the furnace where the high temperature combustion zone is formed and having four tuyere for blowing air to the high temperature combustion zone. The tuyere has the same basic structure as that shown in Fig. 2, and the outer cylinder has an inner diameter of 27 m.
The inner cylinder had an outer diameter of 21.7 mm and an inner diameter of 16.7 mm. Therefore, the cross-sectional area of the inner channel was 219 mm ² and the cross-sectional area of the outer channel was 203 mm ² . The composition of the treated domestic waste was 42 mass% of combustibles, 13 mass% of noncombustibles, and 45 mass% of water.

First, melting treatment was performed under the same blowing conditions as in the prior art. In this operation, 18 household waste
00 kg / h, coke 140 kg / h, limestone 3
Air is charged per tuyere while charging at a rate of 0 kg / h.
30 nm ³ / h and oxygen 25 Nm ³ / oxygen-enriched air h were mixed (oxygen concentration of about 34%), tuyeres 1 Hontori 155
Nm ³ / h was blown. In addition, the flow rates of the inner flow path and the outer flow path were the same. At this time, since the cross-sectional areas of the two flow paths are substantially the same, the air flow velocity from the two flow paths is also substantially the same.

Then, the generated molten slag was intermittently discharged from the melt discharge port about every hour, and the discharge amount was measured. FIG. 4 shows changes in the amount of molten slag discharged per hour during this operation.

When the operation under the above conditions was continued, as shown in FIG. 4, the discharge amount of the molten slag gradually decreased, and the planned discharge amount of 270 kg / h (calculated from the charge composition) was obtained. It has fallen below. From this situation, it was estimated that the incombustibles and ash in the central part of the furnace were not melted or discharged smoothly.

[0036] Thus, changes to blows inner 95 Nm ³ / h of air volume 155 nm ³ / h of oxygen-enriched air per tuyere one from the inner passage, for blowing 60 Nm ³ / h from the outer channel did. By this distribution change, the flow velocity of the inner flow passage was 120 Nm / s, the flow velocity of the outer flow passage was 82 Nm / s, and the flow velocity of the inner flow passage was higher than that of the outer flow passage.

When the blowing conditions are changed as described above,
As shown in FIG. 4, after a while, the discharge amount of the molten slag became large and exceeded the planned discharge amount of 270 kg / h. This is because oxygen-enriched air was sent to the central part of the furnace more than during normal blasting, combustion in the central part of the furnace was promoted, and melting of incombustibles and ash and discharge of the melt were promoted. is there.

[0038] The condition that the blowing conditions of the inner channel and the outer channel was exactly opposite to above, namely, by blowing a 60 Nm ³ / h from the inner passage, for blowing 95 Nm ³ / h from the outer channel conditions But I operated. At this time, the amount of molten slag discharged did not recover as shown in FIG. It is considered that the oxygen-enriched air does not easily reach the central part of the furnace due to deceleration even if the flow velocity of air from the outer flow passage is increased.

(Example 2) The same vertical type waste melting furnace as in Example 1 was used, except that the conditions other than the blowing conditions were the same as those in Example 1.
In the same manner as the above, operation for melting and treating household waste was performed.

In the conventional operation in which the oxygen-enriched air is blown from the inner and outer blowing passages at the same flow velocity, as shown in FIG. 5, a situation occurs in which the molten slag discharge amount gradually decreases.

Therefore, air 6 from the inner flow path per tuyere
Blows 0 nm ³ / h and oxygen-enriched air 77 nm ³ / h of a mixture of oxygen 17 Nm ³ / h, air 70N from the outer channel
Oxygen-enriched air 7 mixed with m ³ / h and oxygen 8 Nm ³ / h 7
The blowing conditions were changed to blow 8 Nm ³ / h. At this time, the total amount of gas blown to each flow path is such that the air flow rate is 1
Hontori 130 Nm ³ / h, the oxygen flow rate is 25 Nm ³ / h, but was the same as the prior art, the oxygen concentration of the oxygen-enriched air blown from the inner passage 38.4 percent, blowing from the outer channel The oxygen concentration of the oxygen-enriched air became 29.1%.
Further, since the flow rates of the oxygen-enriched air in the two flow paths are substantially the same and the cross-sectional areas are also substantially the same, the flow velocities from the two flow paths are substantially the same.

After changing the blowing conditions as described above, the amount of molten slag discharged increased as shown in FIG.
This is because oxygen-enriched air with a high oxygen concentration is being sent to the central part of the furnace, combustion in the central part of the furnace is promoted, the temperature rises, and melting of incombustibles and the discharge of the melt are promoted. .

At this time, since the total flow rate of air and the total flow rate of oxygen have not changed, the operating cost does not increase and
A stable operation can be performed.

It should be noted that the blowing conditions of the inner flow passage and the outer flow passage are completely opposite to the above, that is, 70 N of air is supplied from the inner flow passage.
Oxygen-enriched air 7 mixed with m ³ / h and oxygen 8 Nm ³ / h 7
It blows 8 nm ³ / h, air from the outer channel 60 Nm ³ /
77N oxygen-enriched air mixed with 17Nm ³ / h of oxygen and h
It was operated even under the blowing condition of blowing m ³ / h. At this time,
The amount of molten slag discharged did not recover as shown in Fig. 5, and no effect was observed. It is estimated that when the oxygen concentration in the outer flow passage is increased, the temperature near the side surface of the furnace becomes higher, which is considered to be because it does not contribute effectively to the melting of incombustibles and the discharge of the melt in the central part of the furnace.

(Embodiment 3) The same vertical type waste melting furnace as in Embodiment 1 is used, and the conditions other than the blowing condition are the same as those in Embodiment 1.
In the same manner as the above, operation for melting and treating household waste was performed.

In a conventional operation in which oxygen-enriched air is blown into the inner and outer air flow passages at the same flow rate, as shown in FIG.
There was a situation in which the amount of molten slag discharged gradually decreased.

Therefore, oxygen 2 is supplied from the inner channel per tuyere.
The 5 nm ³ / h, was changed to blowing conditions for blowing air 130 Nm ³ / h from the outer channel. At this time, the total flow rate of air and the total flow rate of oxygen are the same as in the conventional case.

After changing the blowing conditions as described above, the discharge amount of the molten slag increased as shown in FIG.
This is because oxygen is now sent to the central part of the furnace, combustion in the central part of the furnace is promoted, the temperature rises, and melting of incombustibles and the like and discharge of the molten material are promoted.

In the third embodiment, the oxygen concentration in the inner channel is set to 1
This is a test conducted under the ultimate conditions where the oxygen concentration in the outer flow path was set to 00% and the oxygen concentration in the outer flow path was set to 21%, and Example 2 was advanced. Comparing Example 2 and Example 3, the recovery of the molten slag discharge amount is faster in Example 3, and Example 3 is more effective.

Example 4 A test was conducted to further improve the method of Example 3. The same vertical waste melting furnace as in the case of Example 1 was used, and the operation for melting household waste was performed under the same conditions as Example 1 except for the blowing conditions.

In this test, the tuyere was replaced. The replaced tuyere had the same basic structure as that shown in FIG. 2, but the outer cylinder had an inner diameter of 27 mm, the inner cylinder had an outer diameter of 13.8 mm and an inner diameter of 7.8 mm. Therefore, the cross-sectional area of 48 mm ² of the inner passage, the cross-sectional area of the outer flow path is 423mm ^2.

First, in order to perform the operation by the conventional air blowing method, of oxygen-enriched air (the same oxygen concentration (about 34%) as in Example 1) 155 Nm ³ / h, which is blown from one tuyere,
15 Nm ³ / h from the inner channel, 140 Nm from the outer channel
³ / h was blown to make the flow velocities in the inner and outer channels approximately the same.

When the operation by the conventional air blowing method was continued, as shown in FIG. 7, the discharge amount of the molten slag decreased and remained below the planned discharge amount of 270 kg / h.

Therefore, oxygen of 25 Nm ³ /
h, the blowing conditions were changed to blow 130 Nm ³ / h of air from the outer flow path. At this time, the flow velocities in the inner and outer blast channels were 145 Nm / s for oxygen in the inner channel and 85 Nm / s for air in the outer channel.

After changing the blowing conditions, as shown in FIG. 7, the discharge amount of the molten slag rapidly increases, and oxygen is blown from the inner flow passage and at a flow velocity higher than the outer flow passage. It turned out that the effect was great.

In the tests of Examples 1 to 4 described above, when the operation under the conventional conditions in which oxygen-enriched air was blown to the inner and outer blower flow paths at the same flow rate, the amount of molten slag discharged was Although the situation has fallen, such situations do not always occur, but only occur sporadically. However, when such a situation occurs, conventionally, the amount of fuel such as coke is increased, the oxygen concentration of the oxygen-containing gas blown from the tuyere is increased, or the temperature is increased. I was taking steps to change it. Such a drastic change in the blowing conditions has a great influence on the overall operation of the melting furnace, which may cause another operational change such as a change in the temperature and heat generation amount of the produced gas. In addition, when the air blowing conditions are largely changed as described above, the operating cost is increased. For this reason, there has been a demand for a technique for promptly recovering the melting and the smooth discharge of the melt such as incombustibles without increasing the operating cost and minimizing the fluctuation of other operations.
The present invention is an epoch-making technology that can meet this demand.

[0057]

According to the present invention, the tuyere for blowing the oxygen-containing gas has the two air flow passages including the inner flow passage and the outer flow passage, and the air blow condition can be changed for each air flow passage. . Then, while keeping the total flow rate of the oxygen-containing gas to be blown constant, only by changing the distribution, the combustion in the central part of the furnace is promoted and the temperature is raised, and the melting of incombustibles and the discharge of the melt are smoothed. Can be

Therefore, when the discharge of the melt from the melt discharge port is delayed, the consumption of fuel such as coke and oxygen is increased to raise the temperature near the tuyere excessively. It is possible to smoothly melt the incombustibles and the like and discharge the melted material in the central part of the furnace, thereby stabilizing the overall operation.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an embodiment relating to the configuration of a vertical waste melting furnace of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of tuyere provided in a vertical melting furnace according to the present invention.

FIG. 3 is a diagram illustrating an example of a method for blowing air into the vertical melting furnace of the present invention.

FIG. 4 is a diagram showing changes in the amount of molten slag discharged in the operation of Example 1.

FIG. 5 is a diagram showing changes in the amount of molten slag discharged in the operation of Example 2.

FIG. 6 is a diagram showing changes in the amount of molten slag discharged in the operation of Example 3;

FIG. 7 is a diagram showing changes in the amount of molten slag discharged in the operation of Example 4.

[Explanation of symbols]

10 Vertical waste melting furnace 12 Lower furnace 13 booth 14 Product gas outlet 15 Melt discharge port 16 Tuyers for blowing oxygen-containing gas to the high-temperature combustion zone 30 inner cylinder 31 outer cylinder 33 inner channel 34 Outer channel 50a, 50b Flow controller 51a, 51b Flow controller 52 Control device 53,54 header 60 Deposited deposits 61 High temperature combustion zone

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshihiro Tatami             1-2-1, Marunouchi, Chiyoda-ku, Tokyo             Main Steel Pipe Co., Ltd. F term (reference) 3K061 AA16 AB03 BA01 CA08 DB16                 3K062 AA16 AB03 BA02 CB04 DA07                       DA32 DB06 DB09                 3K065 AA16 AB03 BA01 GA03 GA13                       GA22 GA32 GA53                 4K001 BA24 EA07 GA01 GB03                 4K045 AA01 BA10 GB12 GB15

Claims (6)

[Claims] 1. A vertical melting furnace in which a high-temperature combustion zone for melting an object to be processed deposited in the furnace is formed in a lower portion of the furnace, and a tuyere flow path for blowing an oxygen-containing gas to the high-temperature combustion zone. The vertical melting furnace is characterized by being divided into two, an inner side and an outer side. 2. The method for blowing air to a high temperature combustion zone in a vertical melting furnace according to claim 1, wherein the flow rate of the oxygen-containing gas blown from the inner flow passage is larger than that of the oxygen-containing gas blown from the outer flow passage. A method for blowing air into a vertical melting furnace, which comprises: 3. The method for blowing air to a high temperature combustion zone in a vertical melting furnace according to claim 1, wherein the oxygen concentration of the oxygen-containing gas blown from the inner flow passage is the oxygen concentration of the oxygen-containing gas blown from the outer flow passage. A method for blowing air to a vertical melting furnace, which is characterized in that the air is blown higher. 4. The method for blowing air to a high temperature combustion zone in a vertical melting furnace according to claim 1, wherein the gas blown from the inner flow passage is oxygen and the gas blown from the outer flow passage is air. A method for blowing air into a vertical melting furnace that is characteristic. 5. The method for blowing air to a vertical melting furnace according to claim 4, wherein the flow rate of oxygen blown from the inner flow passage is set higher than the flow velocity of air blown from the outer flow passage. 6. The method for operating a vertical melting furnace according to claim 1, wherein the air is normally blown from the inner flow passage and the outer flow passage under the same conditions, and when the discharge amount of the melt is reduced, Item 2
A method of operating a vertical melting furnace, characterized by changing to any one or a plurality of blowing methods according to claim 5.