JP2003065510A - Swirl type melting furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swirl type melting furnace in which the inlet part of a melting chamber may not be possibly closed due to the adhesion of solid materials included in thermally decomposed gas and the thermally decomposed gas can be retained in the melting furnace for a long time. SOLUTION: Combustion air from a first air supply port 5 is supplied to a direction opposite to the swirl flow of decomposed gas introduced from an introducing port 3 to weaken the swirl flow of the decomposed gas. The swirl flow of the thermally decomposed gas is strengthened again by combustion air from a second air supply port 6 in the downstream side thereof, to adequately mix the combustion air with the thermally decomposed gas in the vicinity of the first air supply port 5, to accelerate the ignition speed of the thermally decomposed gas, and to raise the temperature of the furnace to high temperature. Combustible materials in the solid materials are assuredly burnt, and incombustible materials caught by the wall surface of the melting chamber 1 are molten in a short time to make them flow downward. Thus, the solid materials are prevented from being accumulated on the wall surface of the upper part of the melting chamber 1 and closing the inlet part of the melting chamber 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swirl-type melting furnace for combusting pyrolysis gas or char to melt the ash while swirling pyrolysis gas containing solid matter such as ash or char.

[0002]

2. Description of the Related Art As a system capable of detoxifying and reducing the volume of waste, a gasification and melting system combining a thermal decomposition furnace and a melting furnace is drawing attention. A swirl type melting furnace is a typical melting furnace used in this gasification and melting system.

FIG. 4 shows an example of a swirl type melting furnace described in Japanese Patent Laid-Open No. 2000-234715. This swirl-type melting furnace is of a vertical type, and an inlet 52 for a pyrolysis gas containing solid matter generated in the pyrolysis furnace is provided at the upper end side of the melting chamber 51.
A first blowing port 53 for combustion air is provided, and a second blowing port 54 for combustion air is provided below the first blowing port 53. The first blowing port 53 is provided at the lower end of an air supply pipe 55 hanging from the ceiling of the melting chamber 51, and the introduction port 52 for the pyrolysis gas is provided in an annular passage 56 formed around the air supply pipe 55. It opens in the tangential direction. Therefore, the pyrolysis gas introduced into the annular passage 56 from the inlet 52 is
A swirling flow is sent into the melting chamber 51.

Although not clearly shown in the drawing, it is described that the first blowing port 53 is provided with a multi-hole nozzle or a swirling nozzle. There is no particular description about the second blowing port 54.

In this type of swirl-type melting furnace, the pyrolysis gas is swirled in the melting chamber 51, and first and second blowing ports 53 and 54 (in some cases, third or more blowing ports are provided). Combustion air is mixed with the combustion air blown from. Further, the solid matter is trapped on the wall surface of the melting chamber 51, the char that is a combustible component thereof burns, and the ash that is a non-combustible component melts. Then, the melted molten slag and the combustion exhaust gas are discharged from the discharge port provided on the lower end side of the melting chamber 51.

Therefore, in the swirl type melting furnace, since the ash content is captured on the wall surface of the melting chamber 51, the residence time in the melting chamber is long and the ash content can be reliably melted. The swirl type melting furnace is a vertical type in which the pyrolysis gas is fed in the vertical direction, but there is also a horizontal type in which the pyrolysis gas is fed in the horizontal direction.

[0007]

As described above, in the swirl-type melting furnace, the pyrolysis gas is swirled in the melting chamber and the ash content is captured on the wall surface of the melting chamber to prolong the residence time and melt the ash. In order to increase the efficiency, the conventional swirl-type melting furnace is designed so that the combustion air blown from each of the blowing ports does not disturb the swirling flow of the pyrolysis gas in the melting chamber. In particular, the combustion air from the upstream first blowing port is often blown in the same direction as the swirling direction of the pyrolysis gas.

When the combustion air from the first blowing port is blown in the same direction as the swirling direction of the pyrolysis gas, separation of solids contained in the pyrolysis gas is promoted, but the melting chamber into which the combustion air is blown. Since the pyrolysis gas and combustion air are not mixed well near the inlet of the furnace, the combustion is bad and the temperature inside the furnace does not rise to a high temperature, so the char trapped on the wall surface and the ash content are not sufficiently melted, There is a possibility that the entrance portion of the chamber may be blocked by solid matter attached to the wall surface.

Therefore, an object of the present invention is to provide a swirl-type melting furnace in which there is no risk of clogging of the inlet of the melting chamber due to adhesion of solids contained in the pyrolysis gas.

[0010]

In order to solve the above-mentioned problems, the present invention is directed to a gas introduction port into one end of a melting chamber, into which a pyrolysis gas containing solid matter is introduced so as to swirl in the melting chamber. And a first air blowing port into which combustion air is blown, and at least a second air blowing port into which combustion air is blown is provided on the downstream side of the first air blowing port to discharge the pyrolysis gas. In a swirl-type melting furnace that burns while swirling in a melting chamber to melt solid matter contained in the pyrolysis gas, and discharge the combustion exhaust gas and the molten slag to an outlet provided on the other end side of the melting chamber. Combustion air from the first air blowing port is blown so as to weaken the swirl flow of the pyrolysis gas, and combustion air from the second air blowing port is blown into the weakened swirl flow of the pyrolysis gas. Strengthen It adopted a structure in which blown into the cormorants.

That is, by blowing the combustion air from the first air blowing port so as to weaken the swirl flow of the pyrolysis gas, the swirl flow of the pyrolysis gas is disturbed and sufficiently mixed with the combustion air. . If the mixing is sufficient, combustion of the pyrolysis gas is improved, the temperature in the furnace becomes high, and the combustion of char in the swirling flow is promoted. Then, the amount of char trapped on the wall surface decreases, and the ash trapped on the wall surface also melts in a short time due to the high temperature and flows down the wall surface. There is no fear of being blocked. Further, since the pyrolysis gas whose swirl is weakened can strengthen the swirl flow again with the combustion air from the second air blowing port, it is well mixed with the combustion air from this second air blowing port, and char etc. The combustible components of are completely burned.

The combustion air from the second air blowing port does not necessarily need to strengthen the swirl flow of the pyrolysis gas in the same direction as the initial introduction direction, but it may strengthen the swirl flow in the opposite direction to the introduction direction. You can blow it.

As means for weakening the swirling flow of the pyrolysis gas, a method of blowing combustion air from the first air blowing port in a direction opposite to the swirling direction of the pyrolysis gas can be adopted. .

By providing a swirl vane at the first air blowing port, the combustion air blown from the first air blowing port can be swirled in the direction opposite to the swirling direction of the pyrolysis gas.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. This swirl-type melting furnace is a vertical type, and as shown in FIG. 1, a tubular portion 2 is connected to the upper end side of an oval-shaped melting chamber 1, and the tubular portion 2 is pyrolyzed containing solid matter. A gas inlet 3 is provided, a first blowing port 4 for combustion air is provided at the lower end of an air supply pipe 5 inserted into the tubular portion 2 from above, and a second blowing port 6 is provided at the side wall of the melting chamber 1. It is provided. A discharge port 7 for the combustion exhaust gas and the molten slag is provided on the lower end side of the melting chamber 1. At the center of the air supply pipe 5, there is provided a fuel supply pipe 8 for supplying auxiliary fuel at the time of ignition or insufficient combustion.

As shown in FIGS. 2 (a) and 2 (b), the introduction port 3 for the pyrolysis gas is opened in the tangential direction of the annular passage 9 formed around the air supply pipe 5 of the tubular portion 2. The pyrolysis gas is introduced so as to swirl counterclockwise in the annular passage 9, forms a counterclockwise swirling flow, and is sent to the upper portion of the melting chamber 1.

The first blowing port 4 has a swirl vane 10 formed of a plurality of inclined plates inclined in a predetermined direction.
Is attached, and the combustion air from the first blowing port 4 is blown into the melting chamber 1 so as to swirl in the clockwise direction opposite to the swirling flow of the pyrolysis gas.

The swirling flow of the combustion air is set smaller than the swirling flow of the pyrolysis gas, and the pyrolysis gas mixes with the combustion air while being weakened by the reverse swirling flow of the combustion air. It burns quickly and maintains the upper part of the melting chamber 1 at a high temperature. Further, the char contained in the pyrolysis gas has a greater chance of contact with fresh combustion air due to the turbulence of the swirling flow, and promotes combustion in the swirling flow. Part of the char and ash are captured on the wall surface of the melting chamber 1, but since the upper part of the melting chamber 1 is hot, the char burns quickly and the ash melts in a short time and flows down the wall surface. The inlet portion of the melting chamber 1 is never blocked by the solid matter attached to the wall surface.

A plurality of the second blowing ports 6 are provided in the upper portion of the side wall of the melting chamber 1, and the combustion air from the blowing ports 6 is blown from the tangential direction to the wall surface,
It swirls in the same counterclockwise direction as the swirling flow of pyrolysis gas. Therefore, the pyrolysis gas having the weakened swirl is mixed with the combustion air while the counterclockwise swirl flow is strengthened again, and the combustible components are completely combusted.

The combustion exhaust gas and the molten slag whose solid content has been efficiently reduced in volume are discharged to the discharge port 7 on the lower end side of the melting chamber 1.

[0021]

EXAMPLE The above-mentioned swirl-type melting furnace was operated to treat the pyrolysis gas containing the solid matter produced in the pyrolysis furnace, and the temperature in the furnace at that time was measured. As a comparative example, a comparison test was performed in which the swirl vane 10 was inclined in the opposite direction and the combustion air from the first blowing port 4 was blown in the same direction as the swirling direction of the pyrolysis gas. In any case, the measurement positions of the temperature in the furnace were the upper part of the oval of the melting chamber 1 immediately below the first blowing port 4 and the central part of the oval below the second blowing port 6. The target operating time was 50 hours.

FIG. 3 shows the measurement result of the temperature in the furnace. In the case of the comparative example, the temperature of the upper part of the oval changed around 700 ° C., and the inlet portion of the melting chamber 1 was blocked by the adhered solid matter within 20 hours of operation, so the test was stopped. on the other hand,
In the case of the embodiment, the temperature of the upper part of the oval is 8
The temperature at the upper part of the oval reached about 1200 ° C. after about 30 hours of operation, exceeding 00 ° C., and the inlet part of the melting chamber 1 was not blocked, and it was possible to operate smoothly until the end. Regarding the temperature at the center of the oval, only a comparison was made at the initial stage of operation, but no significant difference was observed between the two.

From the above results, in the swirl-type melting furnace according to the present invention, the combustion air is well mixed with the pyrolysis gas even near the first blowing port 4, and the upper part of the melting chamber 1 immediately below it is sufficiently inside the furnace. It can be seen that the temperature rises and the clogging of the inlet portion of the melting chamber 1 due to the adhesion of solid matter to the wall surface can be prevented.

In the above-described embodiment, the swirl-type melting furnace is of vertical type, but the swirl-type melting furnace of the present invention can be applied to a horizontal type. Further, the blowing port of the combustion air is not limited to the one having the first and second blowing ports, and is provided on the downstream side of the second blowing port.
Additional air inlets may be provided.

[0025]

As described above, in the swirl type melting furnace of the present invention, the combustion air from the first air blowing port is blown so as to weaken the swirling flow of the pyrolysis gas, and the second air on the downstream side thereof is blown. Since the swirl flow of the pyrolysis gas was strengthened again by the combustion air from the blowing port, the combustion air was sufficiently mixed with the pyrolysis gas even near the first air blowing port, and the ignition speed of the pyrolysis gas was increased. As the furnace temperature rises, char combustion in swirling flow is promoted. As a result, the amount of char trapped on the wall surface decreases, and the ash trapped on the wall also melts in a short time due to the high temperature and flows down the wall surface. Can be prevented from being blocked.

Further, the pyrolysis gas whose swirl is weakened by the combustion air from the first air blowing port can strengthen the swirling flow again by the combustion air from the second air blowing port. The combustible components are completely combusted by being well mixed with the combustion air from the blowing port, and the waste can be efficiently detoxified and reduced in volume.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a swirl-type melting furnace.

2 is a plan sectional view taken along line II-II of FIG. 1, and b is a vertical sectional view of a.

FIG. 3 is a graph showing a transition of temperature inside the furnace when the pyrolysis gas is treated using the swirl-type melting furnace shown in FIG.

FIG. 4 is a partially omitted vertical sectional view showing a conventional swivel melting furnace.

[Explanation of symbols]

1 melting chamber 2 tubular parts 3 entrance 4 blow mouth 5 Air supply pipe 6 blow mouth 7 outlet 8 Fuel supply pipe 9 circular passage 10 swirl blades

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Claims (3)

[Claims] 1. A gas introduction port into which pyrolysis gas containing solid matter is introduced so as to swirl in the melting chamber, and a first air blowing port into which combustion air is blown are provided on one end side of the melting chamber, At least a second air blowing port into which combustion air is blown is provided on the downstream side of the first air blowing port, and the pyrolysis gas is burned while being swirled in the melting chamber to be contained in the pyrolysis gas. Melt the solids,
In the swirl type melting furnace for discharging the combustion exhaust gas and the molten slag to the discharge port provided on the other end side of the melting chamber,
Combustion air from the air blowing port of the above is blown to weaken the swirling flow of the pyrolysis gas, and combustion air from the second air blowing port is strengthened to weaken the swirling flow of the pyrolysis gas. A swirl type melting furnace characterized by being blown. 2. The means for weakening the swirling flow of the pyrolysis gas blows combustion air from the first air blowing port in a direction opposite to the swirling direction of the pyrolysis gas. The swirl-type melting furnace according to. 3. The swirl vane is provided at the first air blowing port, and the combustion air blown from the first air blowing port is swirled in a direction opposite to the swirling direction of the pyrolysis gas. The swirl-type melting furnace described.