JPS6146814A - Slug discharging facility for waste material melting furnace - Google Patents

Abstract

PURPOSE:To perform a continuous discharging of slug by a method wherein a slug discharging pipe passing through a furnace wall of a melting furnace is passed through the furnace wall, the slug discharging pipe is inclined upwardly and the slug and/or metal is overflowed and discharged from the slug discharging pipe. CONSTITUTION:A degree of upward inclination of slug discharging pipe 9 and a position of a side end part 9b in a furnace are preferably made such that a thickness Hb from the side end part 9b of the pipe 9 in the furnace to the level LSL of the slug layer is 100-300mm., preferably 200-300mm. and an inclination angle of about 15 deg.. The melting slug 4 may entangle the metal 3 when the slug is discharged from the slug discharging port 9a, the metal level LFe always keeps a position lower than the slug discharging port 9a, thereby a stable slug layer 4 can be formed. With this arrangement, a frequent degree of lifting or descending of the electrodes is reduced, a stable applied power can be attained and a continuous discharging of slug becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a melting furnace for disposing of municipal waste, and more particularly to a melting furnace slag extraction facility.

[Prior art]

The mainstream method for municipal waste is to incinerate it and then dispose of it in a landfill. However, in recent years, it has become difficult to secure land for landfill disposal, so waste melting treatment methods that further reduce the volume of waste incineration ash have been attracting attention.

There are two methods for melting and processing these wastes: an arc furnace method and a resistance furnace method; however, in the case of the former method, the arc furnace method has the following problems: 1) Voltage and current are unstable due to arc discharge.

2) The frequency of raising and lowering the electrode to maintain arc discharge is so intense that it is difficult to follow it.

It has the following problems.

On the other hand, in the latter treatment method using a resistance furnace, resistance furnaces have traditionally been used for manufacturing ferroalloys, etc., and the heating method is to embed electrodes in the material to be melted and energize it. Since it is an electric melting furnace that generates heat, it does not have the problems of the above-mentioned arc furnace.

There are two types of slag extraction methods after melting in these resistance type melting furnaces: intermittent type and continuous type. Good operation has also been confirmed in the incineration ash experimental equipment.

However, with regard to continuous slag, although there are actual cases in which simple substances are compared, there are no examples of continuous slag containing substances with completely different properties such as metal and slag, such as incineration ash, and the following There are some difficulties.

That is, 1) Measures to prevent erosion at the slag outlet are different depending on the physical properties of the slag and the metal, which are made of 5i01 t A40g * CaO, etc.

2) It is difficult to follow the amount of slag produced in response to changes in the amount of incineration.

6) Repairs take time.

4) Due to contact with the outside air at the slag outlet, a phenomenon of sticking of the molten material occurs.

5) In the case of intermittent slag, tapping and closing operations are required frequently.

On the other hand, in the melt processing method, the temperature of the processed material is as high as 500 to 700°C, compared to the incineration method, and the danger is correspondingly higher, requiring a higher degree of skill. Therefore, there is a growing need for a continuous slag extraction system that can reduce the amount of work as much as possible.

Japanese Patent Application Laid-Open No. 56-77 describes a closed arc furnace that continuously extracts slag without tapping.
No. 611 has a slag outlet drilled in the center of the hearth of the hearth, the upper part of this slag outlet is surrounded by an embankment-like dam, an airtight device is attached to the slag outlet, and the furnace An electric arc furnace for waste treatment is proposed which is provided with a shell or a furnace lid with a gas outlet and a waste input.

In the case of the above-mentioned arc furnace, since the slag outlet is located at the bottom of the furnace, the arc furnace must be installed at a high place, and there are disadvantages such as the need for separate mechanisms such as seals.

Therefore, in melting municipal waste incineration ash in a melting furnace, there has been a demand for the development of equipment that can continuously discharge slag with a simple mechanism.

[Summary of the invention]

The present invention has been made in view of the problems of the prior art, and is suitable for processing waste materials such as incineration ash containing components such as metal and slag in an electric resistance melting furnace. The purpose is to provide equipment that can perform continuous operations, and to streamline and make the work safer.

The present invention provides an electric resistance melting furnace that melts waste incineration ash, forms a slag layer and a metal layer, and discharges the molten slag. This slag extraction equipment for a waste melting furnace is characterized in that the slag extraction conduit is bored and the slag extraction conduit is inclined upward, and the slag and/or metal is overflowed and discharged from the slag extraction conduit.

[Embodiments of the invention]

The present invention will be described based on the drawings which are examples of embodiments.

FIG. 1 is an explanatory diagram of an apparatus according to an embodiment of the present invention.

In the figure, reference numeral 1 denotes an electric resistance melting furnace made of a steel shell, refractory bricks, and carbon block lining, and is isolated from the outside air by a furnace lid 2 provided at the top of the furnace.

Incineration ash 5, which is the material to be melted, is charged through a charging ash chute 7 provided through the upper lid 2, and a plurality of ash chutes are provided so as to be evenly distributed in the furnace.

Reference numeral 6 denotes an electrode made of a carbon material for heating, which is buried in the layer of the material to be melted so as to be able to be pushed down so that it can be heated and melted by Joule heat.

In such an electric resistance melting furnace, the molten material is stratified and stored in the order of the difference in specific gravity from heavier to lighter at the bottom of the furnace. The lowest layer is the heaviest metal layer 6 with a specific gravity of 6.3 to 6.5.
, above which is a slag layer 4 having a specific gravity of 2.6 to 2.9, and 08 is a waste gas discharge pipe, which is connected to a separately provided waste gas treatment facility. A plurality of slag and/or metal slag discharge conduits 9 are provided around the furnace wall in the vicinity of the electrode 6, penetrating the furnace wall and slanting upward. 9a is a slag outlet, and 9b is an end of the slag conduit on the furnace inner wall side.

The upward inclination of the slag conduit 9 and the position of the end 9b on the furnace inner wall side to achieve the object of the present invention are determined by the slag layer from the end 9b of the slag conduit 9 on the furnace inner wall side. The thickness Hb is 100 to 300 wa tFf 'J or 200 to 300 am, and the immersion depth from the furnace inner wall side end 9b to the slag and/or metal level La in the slag conduit is Ha, Let Hc be the charging thickness at the level La5h and Lst of the melted material, and let the specific gravity of iron, slag, and melted material be ρFee PH4+ P @3b, respectively.
It may be determined using ash as a condition. To satisfy this condition, when the Hb is 200 to 300 tta, it is preferable that the slag discharge conduit 9 be inclined upward by about 15 degrees. At the tip of the slag discharge conduit 9, an easily replaceable erosion prevention attachment 10 is provided. Reference numeral 11 is a metal outlet which is used to open the hole only when stopping the furnace, 12 is a mud gun for opening the slag outlet 9a, and 13 is an opener. The function of slag equipment will be described.

In this electric resistance type melting furnace 1, it is necessary to always form one slag layer 4 with a thickness of 200 to 600 mm and to immerse the electrode 6 in order to perform Joule heating by the electrode 6.

In a conventional horizontal slag outlet, molten slag and unmelted material slag simultaneously, and the slag layer 4 cannot be formed. Therefore, when the metal reached near the level of the slag outlet, there was a drawback that the metal had to be extracted from another slag outlet or the metal portion had to be extracted by tilting the furnace. According to the slag extraction equipment of the first invention, when the molten slag 4 is discharged from the slag outlet 9a, it also involves the metal 3, and the metal level L1 is always at a position lower than the position of the slag outlet 9a. The slag layer 4 can be stably formed.

In addition, even if the metal level Lye rises from the slag outlet 9a, the metal 6 will overflow from the slag outlet 9a due to the load of the slag N4 and the ash layer 5 of the melted material. It becomes a slope.

Therefore, since the slag layer 4 is always formed with a certain thickness or more, the frequency of raising and lowering the electrode 6 is reduced, and the power consumption is stable, making continuous operation possible.

The cross-sectional shape of the slag outlet of the slag conduit 9 may have any shape, but it is preferable to have a circular shape.The cross-sectional area (aperture) should not only be large enough to discharge the slag even during maximum processing, but also be sensitive to the effects of adhesion of slag, etc. It is possible to make the diameter up to the extent that it does not receive any damage, and the structure is such that the diameter exceeds 70 mm depending on the amount of melting.

Therefore, it is possible to follow wide fluctuations in the throughput by simply adjusting the electric power without controlling the molten slag level L8t in the furnace. Since the slag outlet 9a comes into contact with the outside air, it may be kept warm or heated, or may be purged so as not to come into contact with the outside air.

By drilling a plurality of similar slag discharge conduits f9 near the electrode 6 around the furnace wall and using these slag discharge conduits alternately, the furnace can be stopped for a long period of time without repairing the slag discharge conduits. It can be operated continuously without any problems.

Furthermore, according to the present invention, the mud gun 12 when changing the slag outlet 9a
In addition, by using the opener 16, it becomes easy to close and open the slag outlet.

〔Effect of the invention〕

The slag extraction equipment of the waste melting furnace of the present invention can reduce the volume of waste incineration ash from urban areas, etc. in large quantities, and the slag layer of the electric resistance type melting furnace is stably formed, so that the electrodes can be raised and lowered. This makes it possible to stabilize the city power that is used infrequently and to enable continuous operation. Moreover, it is a useful equipment that can be applied not only to melting waste but also to industrial electric furnaces for continuous slag extraction.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the slag extraction equipment of the waste melting furnace of the present invention. 1: Electric resistance melting furnace, 3: Metal, 4 Nisslag, 5:
Material to be melted, 7: Charging chute, 9: Slag outlet, 9a: Slag outlet, 9b: Slag outlet conduit inner end of furnace, 1' D: Attachment for erosion prevention, 11: Metal outlet, La: Outlet Slag and/or metal level of slag conduit, LBt varnish slag layer level, La5h: M melt level, Lye: metal level.

Claims (2)

[Claims] (1) In an electric resistance melting furnace that melts waste incineration ash, forms a slag layer and a metal layer, and releases the molten slag, a slag extraction conduit that penetrates the walls of the melting furnaces is bored around the furnace wall. 1. A slag extraction facility for a waste melting furnace, characterized in that the slag extraction conduit is provided and the slag extraction conduit is inclined upward, and the slag and/or metal is overflowed and discharged from the slag extraction conduit. (2) When sloping the slag conduit upward, the position and degree of inclination of the end of the slag conduit on the furnace inner wall side are set as follows: Ha×ρ_F_e<Hb×ρ_s_l+Hc×ρ_a_
s_hHb: 100 to 300 mm However, Ha: Immersion depth from the end of the furnace inner wall to the slag and/or metal level in the slag conduit Hb: Thickness Hc of the slag conduit from the end of the furnace inner wall to the slag layer level : Charging thickness of the material to be melted ρ_F_e: Specific gravity of iron ρ_s_l: Specific gravity of slag ρ_a_s_h: The waste melting furnace according to claim 1, characterized in that it is determined based on the conditions of the specific gravity of the material to be melted. Tailing equipment.