JPH11159736A - Burner type surface melting furnace for waste incineration ash - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a burner type surface melting furnace for waste incineration ash which has a long service life and can be maintained easily. SOLUTION: The tuyere 6 of a burner type surface melting furnace and a hearth 5 near the tuyere 6 are constituted of two layers of an upper-layer castable refractory 36 and a lower-layer castable refractory 31 and water-cooled tubes 32 are laid between the refractories 36 and 31. Then the quantity of water made to flow to the tubes 32 is adjusted so that solid-phase slug 38 may always cover the surface of the upper-layer castable refractory 36 by monitoring the outputs of thermocouples 37a-37d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for melting incinerated ash disposed on a hearth by a burner to form molten slag, and dropping the molten slag into water from a tuyere at the end of the hearth. The present invention relates to a burner type surface melting furnace for refuse incineration ash which is made to solidify.

[0002]

2. Description of the Related Art A waste incineration ash burner type surface melting furnace is a nodular form of scattered incineration ash (hereinafter referred to as fly ash) discharged from a refuse incinerator and designated as special management or general waste. This is a device for solidifying into a chemically stable substance, reducing the volume, and recycling. A burner type surface melting furnace for such refuse incineration ash will be described with reference to the drawings.

FIG. 4 is a schematic view of a conventional incineration ash burner type surface melting furnace. In the figure, 1 is fly ash, which is put into a container 3 from a hopper 2. 4 is a pusher, which is arranged at the bottom of the container 3. Reference numeral 5 denotes a hearth, which is formed of a dense Al ₂ O ₃ —SiO ₂ refractory material having excellent heat resistance and slag resistance. The surface of the hearth 5 is inclined toward the tuyere 6 formed at the end. Reference numeral 7 denotes a water tank, which is arranged adjacent to the tuyere 6. 7a is water. A melting furnace 8 is provided with a kerosene burner 9. 9a is the flame of the kerosene burner 9. Reference numeral 10 denotes a bag filter, which is connected to the melting furnace 1 by a pipe 11.
Connected to 0. A blower 12 is connected to the pipe 11.

Next, the operation of a conventional incineration ash burner type surface melting furnace will be described.

When the kerosene burner 9 is ignited, the pusher 4
Pushes fly ash 1 toward tuyere 6. Then, the fly ash 1 is melted by the flame 9a to form a molten slag 13.
Then, the molten slag 13 overflowing from the tuyere 6 falls into the water tank 7 and becomes solid granulated slag 14. Since the molten slag 13 has a large viscosity, it falls in a nodular shape when falling into the water tank 7. Further, the volatile components and the evaporated components contained in the fly ash 1 are vaporized when the molten slag 13 is formed, passed through the pipe 11, adjusted in temperature by the blower 12, and processed by the bag filter 10.

[0006]

By the way, the composition of fly ash 1 varies depending on the region and also in the same region depending on the season, but most of the composition is CaO, SiO ₂ , Al ₂ O.
₃ , which contains some Na ₂ O, Fe ₂ O ₃ , K ₂ O and chlorides, sulfides and the like. In addition, K _{2 in} fly ash 1
An alkaline solution formed by the reaction of O and Na ₂ O with water may be mixed.

FIG. 5 is a detailed schematic cross-sectional view of the vicinity of the tuyere 6 in FIG. When fly ash 1 is melted, alkali vapor,
Steam, carbon monoxide (CO), sulfur dioxide (SO ₂ ),
Chlorine gas (Cl ₂ ) is generated. As described above, the hearth 5 is formed of a dense Al ₂ O ₃ —SiO ₂ refractory material. 20 are formed. Since the value of the thermal expansion coefficient of the material forming the hearth 5 differs from that of the altered part 20, the altered part 20 is changed by the temperature change.
Is peeled off from the hearth 5 and cracks 22 are formed. The crack 22 gradually expands, and the tuyere 6 may break through the hearth 5 as shown in the figure.

It is an object of the present invention to provide a burner type surface melting furnace for incinerated ash which has a long life and is easy to maintain.

[0009]

Means for Solving the Problems In order to achieve the above object, a first means is to form a molten slag by melting a refuse incineration ash disposed on a hearth by a burner, and forming the molten slag into the molten slag. In a burner-type surface melting furnace for refuse incineration ash that is made to fall into water from the tuyere at the end of the hearth and solidified, a water-cooling tube is provided, and the water-cooling tube is denser closer to the tuyere. It is characterized by being arranged inside the floor and the tuyere.

[0010] The second means is the first means, further comprising means for measuring temperature and means for adjusting water flowing through the water cooling pipe, wherein the surface temperature of the hearth falls below the melting point of the molten slag. It is characterized in that the amount of water is adjusted to be as follows.

The third means is that in the first or second means, the hearth portion near the tuyere is composed of upper and lower layers, and the water cooling tube is arranged on the surface of the lower layer, and the upper layer is formed on the lower layer. It is characterized by being configured to be exchangeable.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

FIG. 1 is a detailed schematic cross-sectional view of the vicinity of a tuyere of a burner type surface melting furnace for incinerated ash according to an embodiment of the present invention. And the description is omitted. In the figure, 30a, 30b, 30
c is a protective plate having a thickness of 1.0 to 5.0 mm and a high Cr-high Ni alloy, Inconel 625, which is excellent in corrosion resistance.
(22Cr-60Ni), SUS310 (25Cr-2)
0Ni) or the like. Protection plates 30a, 30
The joint between the b and the hearth 5 is jointed with a dense powder of a material of SiO ₂ —Al ₂ O ₃ system. Reference numeral 31 denotes a lower layer castable, which is formed of a brick made of SiO ₂ —Al ₂ O ₃ . Reference numeral 32 denotes a water-cooled tube, which is a lower castable 3
2 and is arranged close to the tuyere 6 as shown in FIG. 2 which is a plan view. The supply side is connected to the tank 35 via the control valve 33 and the pump 34, and the return side is connected to the tank 35. And
SiO ₂ -Al ₂ O while has material and between the lower castable 31 and the protective plate 30c of the cooling water pipe 32 and the protective plate 30c
Jointed with ₃ series of dense powder. 36 is an upper castable, chromia type with excellent slag resistance,
It is made of magnesia-chromia, zirconia, spinel or spinel + chromia. Then, the upper castable 36, the protection plate 30b, and the protection plate 3
Between 0c the material is joint processed by powder dense of SiO ₂ -Al ₂ O ₃ -based. 37a, 37b, 37
Reference numerals c and 37d denote thermocouples, which are arranged at positions 5 to 20 mm from the surface of the upper layer castable 36.

Next, the operation of this embodiment will be described.

The kerosene burner 9 is ignited, and the temperature of the fly ash 1 is set to about 1300 to 1350 ° C. Then, the fly ash 1 is melted to become a molten slag 13. In this state, water is supplied to the water cooling tube 32 to lower the surface temperature of the upper castable 36 from 1250 to 1
Bring to 280 ° C. Then, the molten slag 13 in contact with the surface of the upper castable 36 solidifies and solidified slag 38
Is formed, and the formed solid phase slag 38 covers the upper layer castable 36. After the solid phase slag 38 is formed, the outputs of the thermocouples 37a to 37d are monitored, and the upper castable
The opening of the control valve 33 is adjusted so that the surface temperature of No. 6 becomes 1250 to 1280 ° C.

The solid phase slag 38 is a kind of porcelain, and has high heat resistance and almost no air permeability. As a result, when the solid phase slag 38 is formed, the molten slag 13 or corrosive steam or gas hardly comes into contact with the upper castable 36. Therefore, the upper castable 36 is hardly combined with the components contained in the molten slag 13 to form the altered portion 20, and the upper castable 36 is hardly eroded by corrosive steam or gas. Moreover, even if cracks enter the surface of the solid phase slag 38, the molten slag 13 immediately enters the crack and closes the crack, so that no crack remains. When the surface of the protection plate 30b is covered with the solid phase slag 38 as shown in the figure, the protection plate 30b is also protected by the solid phase slag 38 and is hardly damaged. As described above, since the composition of the fly ash 1 varies depending on the region and the season, it is desirable to control the temperature while observing the state of formation of the molten slag 13 and the solid phase slag 38 through, for example, a viewing window (not shown).

In this embodiment, the protective plate 3 is placed between the hearth 5 and the upper castable 36 and the lower castable 31.
Since 0a to 30c are arranged, it is easy to inspect or replace the upper castable 36 and the lower castable 31.

The distance L between the upper castable 36 and the lower castable 31 is, for example, the kerosene burner 9.
May be in a range exceeding 1200 ° C.

Although the upper castable 36 is made of bricks, it may be formed by spraying or pouring. Further, the lower layer castable 31 may be formed by a casting method.

Further, if the position of the thermocouples 37a to 37d from the surface is shallower than 5 mm, more appropriate temperature control becomes possible.

Further, as shown in FIG. 3, the water cooling tubes 32 may be arranged in a meandering manner at intervals p1 to pn, and the intervals may be narrowed as approaching the tuyere 6 (p1 side in the drawing).

In the above description, a burner type surface melting furnace of a burner type has been described, but the present invention can also be applied to an electric type surface melting furnace such as an arc type, a plasma type or an electric resistance type.

[0023]

As described above, according to the present invention,
The incineration ash disposed on the hearth is melted by a burner to form a molten slag, and the molten slag is dropped into the water from the tuyere at the end of the hearth to solidify the ash. In the burner type surface melting furnace, a water-cooled tube is provided, and the water-cooled tubes are arranged closer to the tuyere so as to be closer to the tuyere, so that the molten slag contacting the upper castable is solid phase. Turns into a slag and covers the upper castable. This solid phase slag has high heat resistance,
Since there is little air permeability, the molten slag or corrosive vapor or gas hardly comes into contact with the upper castable, and the life of the upper castable can be extended.
Further, since the means for measuring the temperature and the means for adjusting the water flowing through the water cooling pipe are provided, the solid phase slag can be reliably maintained. Furthermore, the hearth and the tuyere are composed of two layers, upper and lower, and the water cooling tube is arranged on the surface of the lower layer, and the upper layer is replaceable. .

[Brief description of the drawings]

FIG. 1 is a detailed schematic cross-sectional view of the vicinity of a tuyere of a burner type surface melting furnace for incinerated ash according to an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement of water cooling tubes.

FIG. 3 is another plan view showing the arrangement of the water cooling tubes.

FIG. 4 is a schematic diagram of a conventional incinerated ash burner type surface melting furnace.

FIG. 5 is a detailed schematic cross-sectional view around the tuyere 6 in FIG.

[Explanation of symbols]

 5 Hearth 6 Tuyere 31 Lower castable 31 32 Water cooling tube 36 Upper castable 36 37a-37d Thermocouple 38 Solid phase slag

Claims (4)

[Claims] 1. A slag is melted by a burner to form molten slag, which is disposed on a hearth, and the molten slag is dropped into water from a tuyere at an end of the hearth to be solidified. In a burner type surface melting furnace for refuse incineration ash, a water cooling pipe is provided, and the water cooling pipes are arranged closer to the tuyere and arranged closer to the inside of the furnace hearth and the tuyere. Ash burner type surface melting furnace. 2. A method according to claim 1, further comprising providing a temperature measuring means and a water adjusting means for flowing the water through the water cooling pipe, and adjusting an amount of water so that a surface temperature of the hearth is equal to or lower than a melting point of the molten slag. A burner type surface melting furnace for incinerated ash according to claim 1. 3. The hearth portion near the tuyere is constituted by two layers, upper and lower, and the water cooling tube is arranged on the surface of the lower layer, and the upper layer is replaceable. Item 4. A burner-type surface melting furnace for incineration ash according to Item 2. 4. The method according to claim 1, wherein the upper layer is formed of a chromia-based, magnesia-chromia-based, zirconia-based, spinel or spinel + chromia-based material, and the lower layer is formed of a SiO ₂ -Al ₂ O ₃ -based material. Item 4. A burner type surface melting furnace for incineration ash according to Item 3.