JPH03263510A - Slag disposal device of surface melting furnace - Google Patents

Abstract

PURPOSE:To obtain slag of high strength and good quality by providing a separated furnace of a specified construction right below the slag boat of a surface melting furnace. CONSTITUTION:In a surface melting furnace 1 the furnace body is formed by fitting an inner cylinder 2 slidably into an outer cylinder 3 and in a separated furnace 17 that is provided below the outer cylinder 3 a cylindrical furnace space 18 extending horizontally is formed. The molten slag 5 flows tangentially into the furnace space 18 with the exhaust gas 19 from a slag boat 6 and flows in a revolving flow along the internal circumferential face of the separated furnace 17 and stay in a laminar state along the inner face, and is separated from the exhaust gas 19. Further, the unburned combustion gas in the exhaust gas 19 burns in the furnace space 18 with a high load and at the same time the radiation heat in the main combustion chamber 15 is radiated so that the temperature in the furnace is maintained at a high temperature (1400-1500 deg.C) that is required for holding the fluidity of the slag 5. With this arrangement the slag that is taken out of the separated furnace 17 and solidifies is dense, and it has high strength and good quality, and a low NOx in the exhaust gas is provided in the complete high-load combustion of the unburned gas.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a slag treatment apparatus for a surface melting furnace for melting a dried cake of sewage sludge or incineration residue from an incinerator.

Conventional technology Conventionally, in a surface melting furnace for melting incineration residue or dried sludge cake, a secondary combustion chamber is formed below the slag bowl 1-, and a flue is provided in communication with the secondary combustion chamber.
The molten slag dripping from the slag port is separated from the exhaust gas while performing two-stage combustion of the exhaust gas in the secondary combustion chamber.
One method is to stop the droplets of molten slag falling through the secondary combustion chamber on a water-sealed conveyor and take them out, and the other is to stop the droplets of molten slag falling from the slag port with a damper and then take them out. There was a method in which the material was cooled and then dropped onto a conveyor.

Problems to be Solved by the Invention However, in the surface melting furnace described above, the residence time of the exhaust gas in the secondary combustion chamber is short, so there is a problem that it is not possible to sufficiently reduce NOx in the exhaust gas through two-stage combustion. was there. In addition, the temperature inside the furnace in the secondary combustion chamber is maintained by the heat generated by combustion in the secondary combustion chamber and the radiant heat irradiated from the main combustion chamber through the slag port, but in the conventional water cooling system, The radiant heat passes through the secondary combustion chamber and is absorbed by the heat of evaporation of the water sealing the conveyor. Due to this heat loss, the temperature inside the furnace decreases, and the inner wall of the secondary combustion chamber and the slag There was a problem in which slag adhering to the bottom opening of the port solidified.

The slag treated in the water-cooling method has a problem in that, because the molten slag is rapidly cooled, it becomes porous and fragile, and disintegrates into fine particles. In addition, in the air cooling system, the slag solidifies into large lumps, so it was necessary to crush the slag lumps into a size that can be transported by a conveyor.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a slag processing apparatus for a surface melting furnace that can obtain high-quality slag that has high strength and an appropriate shape.

Means for Solving the Problems In order to solve the above problems, the present invention provides a separation furnace that connects a flue directly below the slag port of a surface melting furnace to collect the molten slag dripping from the lower end opening of the slag port. At the same time, the furnace space formed inside the separation furnace is formed into a horizontally extending cylindrical shape, and the slag port is arranged so that the exhaust gas discharged from the slag port along with the molten slag flows into the furnace space from the tangential direction. The structure is such that the separation furnace is in communication with the separation furnace.

Operation With the above-described configuration, the molten slag dripped from the slag port flows tangentially into the furnace space of the separation furnace together with the exhaust gas, and flows as a swirling flow along the inner peripheral surface of the separation furnace. Therefore, the swirling flow causes an effect similar to that of a cyclone, and droplet-shaped molten slag with a large specific gravity stays in a layer along the inner surface of the separation furnace and is separated from the exhaust gas.

The swirling flow combusts the unburned gas in the exhaust gas under high load in the furnace space, and the radiant heat in the main combustion chamber of the surface melting furnace irradiates the molten slag remaining on the inner peripheral surface of the separation furnace through the slag port. The temperature inside the separation furnace is maintained at a high temperature necessary to maintain the fluidity of the slag.

This prevents the fluidity of the molten slag remaining in layers on the inner peripheral surface of the separation furnace from decreasing over time, and also ensures sufficient time and temperature for the molten slag to defoam. The slag taken out from the separation furnace and solidified does not become porous, but is given an appropriate cooling rate and becomes dense and of high quality with great strength. Furthermore, even if the unburned content of the material to be melted flows into the separation furnace, the temperature inside the furnace is maintained at a high temperature, so that the unburned content is completely converted into slag.

Additionally, the complete combustion of unburned gas through high-load combustion reduces the amount of NOx in the exhaust gas.

EXAMPLE An example of the present invention will be described below based on the drawings. 1st
2, a surface melting furnace 1 has a furnace body formed by loosely fitting an inner cylinder 2 and an outer cylinder 3, and a furnace ceiling 4 is formed as the bottom of the inner cylinder 2. A slag port 6 for discharging the molten slag 5 is formed at the bottom of the outer cylinder 3. Further, the inner cylinder 2 is provided to be able to rise and fall freely with respect to the fixed frame 7, and an inner cylinder lifting device 9 is interposed between the lifting frame 8 that supports the inner cylinder 2 and the fixed frame 7. Further, the outer cylinder 3 is attached to the fixed frame 7 with a receiving roller I.
The outer cylinder 3 is rotatably supported around a vertical axis via an outer cylinder 3, and a drive device II for rotationally driving the outer cylinder 3 is interposed between the outer cylinder 3 and the fixed frame 7.

A charging device 112 is provided on the fixed frame 7 so as to communicate with the furnace space formed between the inner cylinder 2 and the outer cylinder 3. 13 into the furnace, and has a double damper structure. Further, the material to be melted 13 charged into the furnace space accumulates in an annular shape around the inner cylinder 2, and forms an inverted conical inclined surface 14 having an angle of repose around the slag port 6. A main combustion chamber 15 is formed by the inclined surface 14 and the furnace ceiling 4, and a plurality of main combustion burners 16 that radiate flames into the main combustion chamber 15 are provided in the furnace ceiling 4.

A separation furnace 17 is provided below the outer cylinder 3 and located directly below the slag port 6, and a cylindrical furnace space 18 extending horizontally is formed inside the separation furnace 17. In addition, the separation furnace I7 and the slag port 19 are connected to the exhaust gas 19 discharged from the slag port 6 together with the molten slag 5.
is communicated with the furnace space 18 so as to flow into the furnace space 18 from a tangential direction. Further, the furnace space I8 is formed in a tapered shape, and a slag discharge port 20 is formed at the front end side of the separation furnace 17, and an auxiliary burner 21 is provided.

The separation furnace 17 communicates with a flue 23 through a smoke exhaust port 22, and the flue 23 communicates with an exhaust gas treatment device 24.
The inside of the flue 23 is maintained at negative pressure. Further, the separation furnace 17 is provided with a cylindrical guide tube 25 located at the circumference of the opening of the smoke exhaust port 22, and an air supply port 2G is formed.

The effects of the Jc configuration will be explained below.

A material to be melted 13 is charged into the furnace space from a charging device 12, and a main combustion chamber 15 is formed below the furnace ceiling 4. Then, the main combustion burner 16 ignites the material 13 to be melted and the air ratio becomes 0.
．． X
The combustion m1η' in the fyu combustion chamber 15 is set to 1300~□
Maintain at 1500°C. The combustion temperature is controlled by controlling the fuel of the main combustion chamber 1-J-IG or by changing the space volume of the main combustion chamber 15 by raising and lowering the inner cylinder 2 using the inner cylinder lifting device 9.

Under normal operating conditions, the material to be melted 13 is melted from the surface side of the inclined surface 14 in contact with the main combustion chamber 15 2, and the molten slag 5 flows down along the inclined surface 14 and flows from the slag port 6 into the separation furnace. 18. Also, the inclined surface 1
4, the inner cylinder 2 is rotated by the rotation of the outer cylinder 3 by the drive device 1N.
A material to be melted 13 is continuously supplied to be cut down from around the lower end of the melting material.

The molten slag 5 dripped from the slag port 6 enters the furnace space 18 of the separation furnace 17 together with the exhaust gas 19 from the tangential force direction at an inflow velocity close to 15-2015-2
It flows in as a swirling flow along the inner circumferential surface of the separation furnace 17. At this time, the guide tube 25 guides the exhaust gas 19 along the inner peripheral surface of the furnace space 18 and prevents the exhaust gas I9 that has flowed into the furnace space 18 from directly flowing into the flue.

Then, the swirling flow causes an action similar to a cyclone, and the molten slag 5 in the form of droplets with a large specific gravity stays in a layer along the inner surface of the separation furnace I7 and is separated from the exhaust gas 19.

Further, due to the swirling flow, unburned gas in the exhaust gas 19 is burned under high load in the furnace space 18 like a cyclone burner, and the molten slag 5 remains on the inner peripheral surface of the separation furnace 17.
The radiant heat in the main combustion chamber 15 is
irradiated through the separation furnace 17, the furnace temperature in the separation furnace 17 is at a high temperature (1400 to 1500) necessary to maintain the fluidity of the slag 5.
℃). At this time, if necessary for high-load combustion, a small amount of air is supplied from the air supply port 26 and fuel is supplied from the auxiliary parser 2I.

This prevents the fluidity of the molten slag 5 that remains in layers on the inner peripheral surface of the separation furnace I7 from decreasing over time, and
Since sufficient time and temperature are ensured for the molten slag 5 to degas, the slag taken out from the separation furnace 17 and solidified becomes porous and has an appropriate cooling rate, making it dense and strong. It will be of good quality. Furthermore, suppose that the unburned content of the material to be melted I3 flows into the separation furnace 17, and ζ is also maintained at a high temperature by keeping the temperature inside the furnace high.
The unburned matter is completely burned and turned into slag. Furthermore, the complete combustion of unburned gas through high-load combustion reduces NO8 in the exhaust gas.

FIG. 3 shows another embodiment of the present invention, and members that perform the same functions as those in the previous embodiment are given the same reference numerals and their explanations will be omitted. In FIG. 3, the wall surface 31 of the separation furnace 17 located above the flue gas 22 is inclined toward the tip side of the separation furnace 17, that is, toward the slag discharge port 20. The exhaust gas 22 flowing in from the slag port 6 is guided into the furnace space 18 and prevented from directly flowing into the flue 23.

FIG. 4 shows still another embodiment of the present invention,
A flue 23 is provided to communicate with the tip side of the separation furnace 17, and the opening of the smoke exhaust port 22 is formed at the periphery of the embankment 4 into a curved part 32. The return portion 32 prevents the molten slag 5 that remains on the inner circumferential surface of the separation furnace 17 from flowing out into the flue, and creates a swirling flow in the furnace space! The outflow of the exhaust gas 19 flowing through the exhaust gas 8 is inhibited to lengthen the residence time.

Further, as shown in FIG. 5, the bent portion 32 may be formed of a cylindrical body 33. In this case, the molten slag 5 and exhaust gas 19 can be suppressed more reliably.

Effects of the Invention As described above, according to the present invention, the inner space of the separation furnace is formed into a cylindrical shape, and the flue gas and molten slag are made to flow in a swirling manner. The unburned gas in the exhaust gas is combusted in a high load in the furnace space, and the molten slag is irradiated with radiant heat from the main combustion chamber through the slag port to separate it from the exhaust gas. The temperature inside the furnace can be maintained at a high temperature necessary to maintain the fluidity of the slag, preventing the fluidity of the molten slag staying in the separation furnace from decreasing over time, and keeping the temperature high enough for the molten slag to defoam. It is possible to obtain high-quality slag that is dense and has great strength by ensuring a suitable time and temperature. Further, by maintaining the temperature inside the furnace at a high temperature, the unburned content of the material to be melted can be completely converted into slag.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is a sectional view taken along the line A-A in FIG. FIG. 4 is an overall configuration diagram showing still another embodiment of the present invention, and FIG. 5 is an overall configuration diagram showing still another embodiment of the invention. 1...Surface melting furnace, 2...Inner cylinder, 3...Outer cylinder, 5
... Molten slag, 6... Slag port, 13...
Material to be melted, 17... Separation furnace, 18... Furnace interior space.

Claims (1)

[Claims] 1. Directly below the slag port of the surface melting furnace, a separation furnace is placed in communication with the flue to collect the molten slag dripping from the lower end opening of the slag port, and a furnace space is formed inside the separation furnace. A surface melting furnace characterized in that the slag port is formed into a cylindrical shape extending in the horizontal direction, and the slag port and the separation furnace are communicated so that the exhaust gas discharged from the slag port together with the molten slag flows into the furnace space from a tangential direction. Slag processing equipment.