JPH11270827A - Vertical rotary melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lowering of temperature due to the solidification of a molten slag by constructing a rotary melting upright furnace such that a fuel pipe, a combustion air pipe and a transport pipe for powdery material to be treated are connected to tubular flame burners which form a tubular flame in a melting furnace body, and the powdery material to be treated is blown into the melting furnace body together with a combustion exhaust gas. SOLUTION: At a lower portion of a melting furnace body 10, a plurality of tubular flame burners 20, 20 are disposed in a tangential direction of the inner periphery of the furnace body 10, wherein to these tubular flame burners 20, 20, a pipe 25 for transporting powder to be treated which transports the material to be treated by airflow, a fuel pipe 26 and an air pipe 27 are connected. By such a construction, the mixture gas of the blow-off fuel and air forms a swirling flow. When the swirling flow is ignited, a tubular flame is formed and this flame is injected into the melting body 10 together with powder to be treated. The combustion gas containing unburned components which is generated by the melting furnace body 10 is mixed with air supplied from a secondary air blow-in nozzle 33 in a secondary chamber 30, and the mixture is burned again to be in a high temperature condition and forms a swirling flow. Accordingly, the dust is melted and flows downwardly along the furnace wall and is discharged together with the molten slag.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical rotary melting furnace for melting and processing powder to be treated such as sludge and waste incineration residues.

[0002]

2. Description of the Related Art In order to reduce the volume of sewage sludge dried powder, incineration residues generated when sewage sludge and municipal waste are incinerated, and to insolubilize and detoxify heavy metals contained therein. A process for melting these components is performed, and a swirling melting furnace is one of the melting furnaces for performing this process. As a melting furnace of this type, for example,
There is one disclosed in JP-A-2-195109. This melting furnace is a vertical furnace in which an outlet for molten slag is provided at the bottom of the furnace and a discharge port for combustion gas is provided at the top of the furnace. Blown powder such as incineration residue is blown with air, and combustibles are burned while forming a swirling flow in the furnace.
This is a furnace configured to melt inorganic components and to discharge the slag. In the furnace where such a melting process is performed, the molten slag adheres to the inner wall of the furnace due to the centrifugal force generated by the swirling flow, and the molten slag flows down the wall and flows down from the outlet at the bottom of the furnace. Is discharged.

In such a furnace, two types of burners, a burner for blowing powder to be treated such as sludge and incineration residue and a burner for burning fuel, are installed. The powder blowing burner is formed in a double-pipe structure, in which the powder is blown out of the inner pipe together with the primary air into a high-temperature furnace, and secondary air is blown out of the outer pipe. The fuel burner is installed to supply heat, and is arranged near the powder blowing burner.

[0004]

In a conventional swirling melting furnace, when a self-combustible powder such as sludge is blown and burned, the powder blown into the furnace burns from the moment of blowing. Rather, combustion starts after a certain period of time. For this reason, a flame is formed from a position away from the tip of the burner. The portion where no flame is present is a low temperature gas mainly composed of combustion air, and the portion where no flame is present is in a low temperature region. Also, in the fuel burner, similarly, a flame is formed from a position distant from the tip of the burner, so that a low temperature region is created in the injection direction of the burner. When combustion is performed in such a state, the inner wall surface in the injection direction of the burner becomes a low temperature region, and the temperature of the inner wall surface decreases. Then, the molten slag flowing down the wall surface is cooled and solidified, and adheres to the wall surface. For this reason, the wall surface located in the injection direction of the burner swells, and the swell gradually grows. If such a swell is formed, this portion becomes an obstacle, and the jet of the burner is disturbed. As a result, the swirling flow in the furnace is not formed in a normal state, and the melting furnace cannot be operated.

An object of the present invention is to provide a vertical swirling melting furnace in which a low-temperature region where molten slag adheres to the inner wall surface of the melting furnace cannot be formed.

[0006]

Means for Solving the Problems In order to achieve the above object, a first aspect of the present invention is a vertical swirling melting furnace provided with an outlet for a molten slag at the bottom of a melting furnace body. A tubular flame burner in which a tubular flame is formed is provided in the main body, and a fuel pipe, a combustion air pipe, and a powder transport pipe to be processed are connected to the tubular flame burner and blown into the melting furnace main body. The processing target powder is blown together with the combustion exhaust gas to be blown.

According to a second aspect of the present invention, in the first aspect, the tubular flame burner is formed in a double tubular shape, and a powder blowing pipe to be treated is provided at a central portion thereof.

In the present invention, the tubular flame burner is
A swirling flow of a gas body composed of combustion air and fuel is created in the combustion tube, the gas body forming the swirling flow is ignited to form a tubular flame in the combustion tube, and high-temperature combustion exhaust gas is ejected directly from the combustion tube. Refers to the burner configured.

In a tubular flame burner, combustion starts inside the burner, and the combustion air is injected at a high temperature, so that a low-temperature region cannot be formed in the injection direction. When the powder to be treated is blown from the tubular flame burner, the powder to be treated and the air for blowing the powder are mixed with the flame or the high-temperature combustion gas at the same time as the blowing, and the temperature becomes high. While heating well, there is no problem of generating a low temperature region in the furnace.

Further, in a melting furnace configured to blow the powder to be processed from a tubular flame burner, both the function of blowing the powder to be processed and the function of burning the fuel are integrated. There is no need to provide separately, and the configuration of the melting furnace is simplified.

[0011]

1 and 2 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, and FIG. 2 is a transverse sectional view of a tubular flame burner mounting portion in FIG. . In the figure, 1
Reference numeral 0 denotes a melting furnace main body for melting the powder to be processed, and 30 denotes a secondary combustion chamber connected to the melting furnace main body 10 for reburning a combustion gas containing unburned components generated in the melting furnace main body 10.

The melting furnace main body 10 has a cylindrical body, a molten slag outlet 11 at the bottom, and a combustion gas outlet 12 at the top. Also, the melting furnace body 10
A plurality of tubular flame burners 20, 20 are attached to the lower portion of the body portion. The burner 20, 20 has a powder transport pipe 25 for transporting powder to be processed, and a fuel pipe 2
6. The air pipe 27 is connected. Tubular flame burner 2
As shown in FIG. 2, 0 and 20 are arranged in a tangential direction of the inner periphery of the furnace main body 10 so that a swirling flow is formed in the furnace by the combustion gas ejected from the burners 20 and 20. Has become.

FIG. 3 is a view showing a schematic structure of a tubular flame burner. The tubular flame burner 20 has a double pipe structure in which a powder to be processed 22 is inserted into the center of a combustion pipe 21. A fuel injection nozzle 23 is disposed at an end of the combustion tube 21 on the side of the powder to be treated, in a tangential direction. Further, primary air injection nozzles 24, 24 are arranged in the tangential direction of the combustion pipe 21 on the same peripheral surface as the arrangement position of the fuel injection nozzle 23. The structure of the fuel injection nozzle 23 differs depending on the type of fuel used. When the fuel is a liquid fuel such as kerosene, for example, fine oil droplets are sprayed from a two-fluid injection valve or a spray nozzle to quickly vaporize the oil. In addition, the primary air blowing nozzles 24, 24 are formed in a slit shape at the tip, so that air is blown at a high speed.

For this reason, a mixed gas consisting of fuel and air swirls in the combustion pipe 21 and flows toward the jet port. When the mixed gas forming the swirling flow is ignited, a tubular flame 50 is formed in the combustion tube 21 as shown in FIG. 4, and this flame is injected into the melting furnace main body 10 together with the powder to be processed. It has become so. At this time, the air for blowing the powder to be treated serves as secondary air.

FIG. 1 will be described again. Secondary combustion chamber 3
Numeral 0 is for reburning the combustion gas containing unburned components generated in the melting furnace main body 10, has a cylindrical shape, and has an opening at the lower end serving as an inlet 31 for the gas containing unburned components. An exhaust gas outlet 32 is provided at the top. A secondary air injection nozzle 33 for reburning the combustion gas containing the unburned portion is attached to a lower portion of the secondary combustion chamber 30. The secondary air injection nozzle 33 is arranged so that a swirling flow is formed in the secondary combustion chamber 30, similarly to the tubular flame burner 20 provided in the melting furnace main body 10.

Numeral 40 denotes a slag discharge section for discharging molten slag. The slag part 40 includes a slag receiving part 41 connected to a lower end of the melting furnace main body 10 and a slag conveyor 42 arranged therebelow. 43 is a slag outlet 11 of the melting furnace main body.
This is an auxiliary burner for heating the molten slag 51 falling from the slag to maintain its fluidity.

The operation of the vertical swirling melting furnace configured as described above is performed as follows. Tubular flame burners 20,2
The primary combustion air is blown into 0, and the fuel is blown and burned. Tubular flames are generated in the combustion tubes of the tubular flame burners 20, 20, and the flames are blown into the melting furnace body 10 to form a swirling flow in the furnace and heat the furnace. Next, the powder to be treated, such as the dried sewage sludge, or the incineration ash of sludge, or the incineration fly ash of municipal waste, is pneumatically transported, and the to-be-processed powder injection pipe 22 of the tubular flame burner is transported.
Blow in from. The powder to be treated is blown into a flame or a high-temperature combustion gas and heated to burn combustibles. The inorganic component adheres to the furnace wall by centrifugal force generated with the swirling flow,
It is further heated and melted to form slag. The molten slag flows down the furnace wall, falls from the slag outlet 11 to the slag part 40, and is discharged from the slag conveyor 42.

On the other hand, the combustion gas containing unburned components generated in the melting furnace main body 10 enters the secondary combustion chamber 30 and mixes with the secondary air blown from the secondary air blowing nozzle 33 to re-burn. It is discharged from the exhaust gas discharge port 32. At this time, dust (combustion ash) of the powder to be processed is scattered together with the combustion gas, but the interior of the secondary combustion chamber 30 is in a high temperature state due to the combustion of the gas containing unburned components. Since a swirling flow is formed in the combustion chamber 30, the dust melts and adheres to the furnace wall, flows down the wall surface, falls into the melting furnace main body 10, and flows together with the molten slag generated here. Is discharged.

As described above, when the powder to be treated is blown from the tubular flame burner 20, the blown air for combustion is injected at a high temperature. Is maintained. For this reason, the phenomenon that the temperature of the inner wall surface in the injection direction of the burner decreases and the molten slag solidifies does not occur.

[0020]

According to the present invention, the melting furnace body is provided with a tubular flame burner in which a flame is formed from inside the burner. The powder to be treated is blown from the tubular flame burner together with the combustion gas. It is configured. Therefore, in the present invention, the combustion air is injected at a high temperature, and the inner wall surface in the injection direction does not have a low temperature at which the molten slag solidifies and adheres.

Further, in the present invention, since the tubular flame burner having both the function of injecting the powder to be treated and the function of burning the fuel is provided, it is not necessary to separately provide a fuel burner, and the structure of the melting furnace is not required. Is simplified.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view illustrating an example of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a tubular flame burner mounting portion in FIG.

FIG. 3 is a view showing a schematic structure of a tubular flame burner.

FIG. 4 is an explanatory diagram showing a combustion state of a tubular flame burner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Melting furnace main body 11 Slag outlet 12 Combustion gas outlet 20 Tubular flame burner 21 Combustion pipe 22 Powder injection nozzle to be treated 23 Fuel injection nozzle 24 Primary air injection nozzle 25 Powder transportation pipe to be processed 26 Fuel pipe 27 air piping 30 secondary combustion chamber 31 flammable gas inlet 32 combustion exhaust gas outlet 33 secondary air injection nozzle 40 slag part 41 slag receiving part 42 slag conveyor 43 auxiliary burner 50 tubular flame 51 molten slag

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI F27B 1/21 F27B 1/21 (72) Inventor Ning Hoshino 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Minoru Suzuki 1-2-2 Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Inventor Akira Nakamura 1-2-1, Marunouchi 1-chome, Chiyoda-ku Tokyo, Japan

Claims (2)

[Claims] 1. A vertical swirling melting furnace provided with an outlet for a molten slag at the bottom of a melting furnace main body, wherein the melting furnace main body is provided with a tubular flame burner in which a tubular flame is formed. A fuel pipe, a combustion air pipe, and a target powder transport pipe are connected to the tubular flame burner, and the target powder is blown together with the combustion gas blown into the melting furnace body. A vertical swirling melting furnace. 2. The tubular flame burner is formed in a double tubular form,
2. The vertical swirling melting furnace according to claim 1, wherein a powder injection pipe to be processed is provided at a central portion thereof.