JP3611348B2 - Electric melting furnace - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an overflow hot water type electric melting furnace used for melting melting materials such as incineration ash and dust generated when incinerating general waste and industrial waste, and an overflow portion of a hot water outlet The refractory was cooled with cooling air, and combustible gas generated in the melting furnace was combusted by the cooling air, and the molten material overflowing from the outlet was heated using the combustion heat. It relates to an electric melting furnace.
[0002]
[Prior art]
Conventionally, a large amount of general waste and industrial waste are incinerated in a garbage incinerator to detoxify and reduce the volume, and incineration ash and dust are landfilled.
However, since the incinerated ash and dust contain harmful substances such as heavy metals and dioxins, there is a risk of environmental pollution after landfill treatment, and securing landfill sites is becoming difficult year by year. , Has caused various problems in practice.
[0003]
Therefore, in order to solve the problems as described above, recently, measures have been taken to further detoxify and further reduce the volume by further melting and solidifying the combustion ash and dust.
This melting and solidification mainly uses combustion melting furnaces that use fuels such as oil and gas, and electric melting furnaces such as arc furnaces, plasma furnaces, and electric resistance furnaces, but cities that require melting and solidification. In the case of a waste incinerator, since there are many cases in which power generation is performed using the combustion heat of waste, surplus power can be used, so there are many examples of using an electric melting furnace, for example, an overflow hot water type electric melting furnace.
[0004]
FIG. 5 and FIG. 6 show an example of this type of overflow hot water type electric melting furnace in the past, and a material to be melted such as incinerated ash by the arc heat from the electrode 21 (graphite electrode) in the melting furnace body 20. 22 is melted, and the molten material 22a accumulated in the furnace bottom is sequentially discharged from the overflow portion of the hot water outlet 23 to the outside. Further, the combustible gas 24 generated by the melting of the material 22 to be melted is discharged to the combustion chamber outside the furnace through the gas discharge port 25 and is recombusted by using auxiliary fuel. This is because when the combustible gas 24 is burned in the melting furnace, the vicinity of the graphite electrode 21 becomes an oxidizing atmosphere, and the oxidation consumption becomes intense.
[0005]
By the way, in the overflow hot water type electric melting furnace, when the amount of overflow (processing amount) of the melt 22a decreases, the melt 22a is cooled in the hot water outlet 23, the fluidity is lowered, and it becomes difficult to flow. In some cases, it will solidify.
Therefore, in the electric melting furnace of FIG. 5, an auxiliary electrode 26 is provided in the vicinity of the furnace wall side of the tap 23, and in the electric melting furnace of FIG. 6, an auxiliary burner 27 for city gas is provided. The object 22a is heated.
[0006]
[Problems to be solved by the invention]
However, in the conventional electric melting furnace in which the auxiliary electrode 26 and the auxiliary burner 27 are provided in the vicinity of the hot water outlet 23 in order to facilitate the discharge of the melt 22a, heating and melting by the auxiliary electrode 26 and the auxiliary burner 27 are performed. Due to the high temperature of the material 22a itself, there is a problem that the erodibility of the melt 22a is large and the life of the refractory in the overflow portion of the tap 23 is extremely short.
[0007]
The present invention was created to solve the above problems, and its purpose is to cool the refractory in the overflow portion of the tap outlet with cooling air to prolong the life of the refractory and to heat it. Provides an overflow hot water type electric melting furnace that burns flammable gas generated in the melting furnace with the refractory cooling air and uses the heat of combustion to stably discharge the melt from the hot water outlet. There is.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the electric melting furnace of the present invention is an overflow in which the melted material such as incineration ash and dust from the waste incinerator is melted with an electrode, and the melt is overflowed from the outlet. In a hot water type electric melting furnace, a cooling air passage for cooling the refractory in the overflow portion is formed in the overflow portion of the hot water outlet, and a terminal portion of the cooling air flow passage is used as a hot water outlet. It is opened, and cooling air that has cooled the refractory is supplied into the outlet, and the combustible gas generated by melting of the melt is burned in the outlet.
[0009]
[Action]
In the electric melting furnace, the molten material such as combustion ash and dust from the refuse incinerator supplied into the furnace is melted and flowed by the arc heat of the electrode, plasma heat or Joule heat of the molten material itself. It becomes a soluble material, overflows from the overflow part of the tap, and is discharged after being cooled by water cooling or air cooling.
[0010]
In the overflow part of the outlet, the cooling air is always supplied to the cooling air flow path, and the inside of the refractory in the overflow part is cooled by the cooling air. As a result, the life of the refractory in the overflow portion is greatly extended.
In addition, the cooling air that has cooled the refractory material in the overflow portion is jetted from the end portion opening of the cooling air flow path into the hot water outlet.
[0011]
On the other hand, the combustible gas generated when the melted material is melted in the melting furnace is sucked from the furnace to the hot water outlet side, and is supplied and mixed with the heated refractory cooling air in the hot water outlet. Thus, it is almost completely burned. This high-temperature combustion exhaust gas is discharged to the outside from the exhaust gas discharge port while heating the melt flowing in the overflow portion. As a result, the melt in the hot water outlet maintains its fluidity, and the hot water is smoothly and satisfactorily performed.
[0012]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an overflow hot water type electric melting furnace according to an embodiment of the present invention, wherein 1 is a furnace body, 2 is a graphite electrode, 3 is a melt supply port, 4 is a hot water outlet, 5 is a hot water outlet, 6 Is an exhaust port for combustion exhaust gas, 7 is a cooling water tank, 8 is a material to be melted such as incineration ash and dust, 8a is a melt, 9 is a combustible gas, 10 is a combustion exhaust gas, 11 is an air flow path for cooling, and 12 is a cooling device An air supply pipe 13 is a cooling fan.
[0013]
The furnace body 1 is formed in a substantially box shape by a side wall 1a, a ceiling wall 1b and a furnace bottom 1c formed of a refractory material such as a castable refractory and a refractory brick, and the side wall 1a is to be melted into the furnace. A melt supply port 3 for charging 8 and a discharge port 4 for discharging the melt 8a in the furnace are formed.
Further, on the downstream side of the hot water outlet 4, there are a hot water outlet 5 for introducing the melt 8 a discharged from the hot water outlet 4 to the cooling water tank 7 and a combustion exhaust gas outlet 6 for discharging the combustion exhaust gas 10 to the outside, respectively. It is formed in a communication state.
[0014]
And in the electric melting furnace of this invention, the cooling air flow path 11 which cools the refractory material of this overflow part 1d is formed in the overflow part 1d of the tap 4.
That is, in this embodiment, the cooling air flow path 11 is provided in the lower part, side surface part and weir part of the runner 14 formed in the overflow part 1d from the furnace to the hot water outlet 5 as shown in FIG. It is configured to be branched so that the refractory in almost the entire area of the overflow portion 1d can be cooled.
In addition, each end portion 11 a of the cooling air flow path 11 is open to the hot water outlet 4 so that the cooling air 15 can be supplied into the hot water outlet 4.
Further, a cooling air supply pipe 12 and a cooling fan 13 are connected to the start end of the cooling air flow path 11 so that the cooling air 15 can be supplied to the cooling air flow path 11. .
[0015]
As the refractory material of the overflow portion 1d forming the cooling air flow path 11, a material that is easy to process the cooling air flow path 11 and that corresponds to the chemical composition and characteristics of the melt 8a is used. Yes. In this embodiment, magnesia dolomite, magnesia calcia and the like are used as the refractory.
[0016]
In the electric melting furnace configured as described above, the melted material 8 such as incineration ash and dust from the waste incinerator supplied into the furnace is melted by the arc heat of the graphite electrode 2 and is fluid. The molten material 8a overflows from the overflow portion 1d of the hot water outlet 4 to the hot water outlet 5 side, is cooled in the cooling water tank 7, and is discharged.
[0017]
At this time, since the cooling air 15 is always supplied from the cooling fan 13 and the cooling air supply pipe 12 to the cooling air flow path 11 in the overflow portion 1d of the hot water outlet 4, the cooling air 15 cools the inside of the refractory in the overflow portion 1d. As a result, the life of the refractory in the overflow portion 1d is greatly extended.
Further, the cooling air 15 that has cooled the refractory in the overflow portion 1 d is ejected from the end portion 11 a opening of the cooling air passage 11 into the hot water outlet 4.
[0018]
On the other hand, the flammable gas 9 generated when the melt 8 is melted in the melting furnace is sucked from the furnace to the outlet 4 side and heated in the outlet 4 for refractory cooling air 15. And is almost completely burned. The high-temperature combustion exhaust gas 10 is discharged to the outside from the combustion exhaust gas outlet 6 while heating the melt 8a flowing through the overflow portion 1d. As a result, the melt 8a in the hot water outlet 4 maintains its fluidity, and the hot water is smoothly and satisfactorily performed.
[0019]
In this electric melting furnace, the combustion air (cooling air 15) of the combustible gas 9 is supplied into the tapping outlet 4 and the combustion exhaust gas 10 is discharged from the combustion exhaust gas outlet 6 to the outside. The central portion of the melting furnace does not become an oxidizing atmosphere, and therefore the graphite electrode 2 is not oxidized and consumed.
[0020]
In the above embodiment, the cooling air flow path 11 is formed directly in the overflow portion 1d of the outlet 4; however, in other embodiments, as shown in FIGS. The cooling pipe 11 ′ is embedded in a serpentine shape below the runner 14 formed in the overflow portion 1 d from the furnace to the hot water outlet 5, thereby forming the cooling air flow path 11. The cooling air 15 may be sent from the cooling fan 13 and the cooling air supply pipe 12 to cool the refractory in almost the entire area of the overflow portion 1d. The end portion 11 a of the cooling pipe 11 ′ is open to the hot water outlet 4 so that the cooling air 15 can be supplied into the hot water outlet 4.
The effect of this embodiment can be the same as that of the first embodiment.
[0021]
【The invention's effect】
As described above, in the overflow hot water type electric melting furnace of the present invention, a cooling air flow path for cooling the refractory in the overflow part is formed in the overflow part of the hot water outlet, and the cooling air flow path is used for cooling. Since the inside of the refractory is cooled by flowing air, the life of the refractory in the overflow portion is greatly extended.
[0022]
Also, the electric melting furnace of the present invention opens the end of the cooling air flow path to the outlet and supplies cooling air, which has cooled the refractory, into the outlet, and is generated from the melt by the cooling air. The combustible gas thus burned is burned in the tap and the melt flowing through the overflow portion is heated by this combustion heat. As a result, the melt in the hot water outlet maintains its fluidity, and the hot water is smoothly and satisfactorily performed.
[0023]
Furthermore, since the electric melting furnace of the present invention uses air for cooling the refractory, it is excellent in safety. That is, when water is used for cooling the refractory, if the cooling water leaks into the furnace, there is a risk of steam explosion due to mixing with the melt, but in the case of air, There is no danger.
[0024]
In addition, the electric melting furnace of the present invention heats the molten material that burns and burns well by simply supplying cooling air to the outlet space, so that it does not flow like a conventional electric melting furnace. No special heating device such as an auxiliary electrode or an auxiliary burner is required, and the running cost and initial cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of an overflow hot water type electric melting furnace according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of an overflow portion of an electric melting furnace.
FIG. 3 is a schematic plan view of an overflow portion of an electric melting furnace in which a cooling air flow path is formed by a cooling pipe.
4 is a schematic cross-sectional view of the overflow portion of FIG.
FIG. 5 is a schematic cross-sectional view of a conventional overflow hot water type electric melting furnace.
FIG. 6 is a schematic cross-sectional view showing another example of a conventional overflow hot water type electric melting furnace.
[Explanation of symbols]
1d is an overflow part, 2 is an electrode, 4 is a tap, 8 is a melt, 8a is a melt, 9 is a flammable gas, 11 is a cooling air flow path, and 11a is a terminal part of the cooling air flow path.

Claims (1)

Electricity of the overflow hot water system in which the molten material (8) such as incineration ash and dust from the waste incinerator is melted by the electrode (2), and the molten material (8a) is allowed to overflow from the hot water outlet (4). In the melting furnace, a cooling air flow path (11) for cooling the refractory in the overflow portion (1d) is formed in the overflow portion (1d) of the outlet (4), and the cooling air flow The end (11a) of the channel (11) is opened to the hot water outlet (4), and the cooling air (15) that has cooled the refractory is supplied into the hot water outlet (4) to melt the melt (8). An electric melting furnace characterized in that the combustible gas (9) generated by the above is burned in the outlet (4).

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