JP2000074353A - Ash processing melting furnace and its operation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ash processing melting furnace and its operation method in which maintenance work for removal of melts fixedly deposited on a lower electrode is eliminated, with good slag quality and with the low running cost. SOLUTION: There are provided an upper electrode 15 disposed vertically movably, a lower electrode 16 disposed on a hearth side while facing the upper electrode 15 and further disposed vertically movably in response to melting conditions of thrown ash 12, and an electric power supply apparatus 17 between both electrodes 15, 16 for switching an arc power supply 30 between hanging characteristics and a voltage adjustable resistance heating power supply 29 having constant voltage characteristic in response to load conditions for supply of electric power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melting furnace for ash processing for melting incinerated ash and fly ash, separating and discharging the melt, and a method for operating the melting furnace for ash processing.

[0002]

2. Description of the Related Art Conventionally, in a melting furnace for ash treatment, a lower electrode disposed and fixed on the furnace bottom side of an electric resistance melting furnace main body, and an upper electrode provided to be movable up and down in opposition to the lower electrode. The incineration ash and fly ash are supplied and the arc heat and the Joule heat are applied through the arc power supply and the resistance heating power supply to heat and melt the incineration ash and fly ash. , Slag, and salt (NaCl, KCl, etc.) are discharged from each of the outlets and collected, thereby reusing resources, particularly effective use of slag. That is, while the lower electrode is fixed, the upper electrode is moved up and down to change the resistance value between the two electrodes, that is, the load, so that the salt is separated from the slag and the metal.

[0003]

However, since the conventional ash treatment melting furnace operates with the lower electrode fixed, there are still the following problems to be solved. When the operation is performed with the lower electrode 50 fixed to the furnace bottom upper surface 51 (see FIG. 5). When the equipment is shut down, the melt 53 remaining on the upper surface 52 of the lower electrode 50 cools and solidifies, and is affected by slag. In some cases, no arc is generated at the time of restart, and as a result, maintenance work for removing the melt 53 on the lower electrode 50 is required. In FIG. 5, reference numeral 54 denotes an upper electrode, reference numeral 55 denotes a metal outlet, reference numeral 56 denotes a slag outlet, and reference numeral 57 denotes a salt outlet. When the operation is performed with the lower electrode 50a fixed at a position slightly higher than the furnace bottom upper surface 51 (see FIG. 6).
Since the salt 58 is uniformly present in the melt 53a (particularly, a large amount of slag is contained) due to thermal convection, the slag port 56
The salt concentration in the slag that comes out of the slag is high, and the quality of the slag is inferior. When resistance heating is stopped to eliminate the heat convection, the melt 5
Since the upper surface 53b of 3a is cooled and solidified by the heat radiation from the air, the operation has been disabled. 6, reference numeral 54a denotes an upper electrode, reference numeral 59 denotes a main current (heat source) locus, and reference numeral 60 denotes a thermal convection locus. When operating with the lower electrode 50b fixed near the outlet 57 (see FIG. 7), the upper and lower electrodes 54b, 50 are located at a position where heat convection hardly occurs.
b, after the melt 53a is made up to the outlet 57, the specific gravity separation of salt and slag is performed well, so the quality of slag is good, but the specific gravity of salt and slag is separated when starting up the equipment. Therefore, when the melt 53a is formed up to the level of the salt outlet 57, all the melt 53a must be formed by arc heating. Therefore, near the furnace bottom, a seed metal (a melt having a resistance value at which resistance heating is performed) is supplied. The running cost is much higher than in the case where the melt 53a is formed up to the salt outlet 57 by resistance heating. 7, reference numeral 61 denotes an arc, reference numeral 62 denotes an ash inlet, and reference numeral 63 denotes ash.

The present invention has been made in view of such circumstances, and does not require maintenance work for removing the melt adhered to the lower electrode, has good slag quality, and has a low running cost. An object of the present invention is to provide a furnace and its operation method.

[0005]

According to the present invention, there is provided a semiconductor device comprising:
The melting furnace for ash processing described above is arranged on the furnace bottom side facing the upper electrode and the upper electrode movably arranged up and down, and can be moved up and down according to the melting state of the ash inputted. A lower electrode disposed between the two electrodes, a power supply device capable of supplying power by switching an arc power supply having a drooping characteristic and a resistance heating power supply capable of adjusting a voltage with a constant voltage characteristic according to a load state. Is provided. The method for operating a melting furnace for ash treatment according to claim 2 supplies electric power between an upper electrode movably arranged vertically and a lower electrode movably arranged vertically on the furnace bottom side. In the operating method of the melting furnace for ash processing for melting and processing the supplied ash, at the time of start-up, the lower electrode is arranged near the upper surface of the furnace bottom, and the upper electrode and the lower electrode are connected by an arc power supply having a drooping characteristic. An arc is generated in between to melt the supplied ash, and after a predetermined amount of melt is formed, it is heated using a resistance heating power supply having a constant voltage characteristic. The method for operating a ash processing melting furnace according to claim 3 is the method for operating an ash processing melting furnace according to claim 2, wherein it is confirmed that the melt exceeds a level of a salt outlet, and The electrode is moved to the vicinity of the surface of the melt to maintain a certain distance from the lower electrode, and the upper layer of the melt is resistance-heated or arc-heated using the arc power supply.

According to a fourth aspect of the present invention, there is provided a method for operating an ash melting furnace according to the third aspect, wherein the resistivity between the two electrodes is equal to or less than a predetermined value and the weight is reduced. After the specific gravity separation of the slag and the light-weight slag, the upper-layer salt of the melt is discharged from the salt outlet, and then the upper electrode and the lower electrode are lowered to remove the melt. Is heated by resistance heating, and the slag in the melt is brought to a temperature at which the slag can be discharged by the resistance heating. The method for operating the ash treatment melting furnace according to claim 5 is:
The method for operating a ash treatment melting furnace according to claim 4, wherein the lower electrode is arranged near the furnace bottom upper surface without leaving the entire amount of the molten material, leaving only an amount capable of performing the resistance heating, and again. Add new ash and perform melting process. The method for operating a ash processing melting furnace according to claim 6 is the method for operating an ash processing melting furnace according to claim 2, wherein it is confirmed that the melt exceeds a level of a salt outlet, and A first step of moving an electrode to a position near the surface of the melt and keeping a constant distance between the lower electrode and the upper layer of the melt by resistance heating or arc heating using the arc power source; After the resistivity between the two electrodes is equal to or less than a predetermined value and the specific gravity separation of the slag which is a heavy material and the salt which is a lightweight material proceeds, the salt in the upper layer of the molten material is discharged from the salt outlet, Next, lowering the upper electrode and the lower electrode, heating the melt by resistance heating, and after the slag in the melt is brought to a temperature at which the slag in the melt can be heated by the resistance heating, from the slag port The third step of tapping and leaving the slag amount capable of resistance heating Repeating the fourth step of re-introducing new ash required number. The method for operating a melting furnace for ash processing according to claim 7 is the method for operating a ash processing melting furnace according to claim 6, wherein, as a final step, when the entire amount of the melt is discharged from the furnace, a small amount remains on the upper surface of the furnace bottom. The upper end surface of the lower electrode is disposed at a position higher than the upper surface of the melt that cools and hardens by a predetermined distance.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is an overall configuration diagram of an ash processing melting furnace to which the ash processing melting furnace operation method according to one embodiment of the present invention is applied, and FIG. FIG. 3 is an explanatory view of the inside of the furnace at the time of hot water preparation, FIG. 3 is an explanatory view of the inside of the furnace from the preparation of a seed bath to the preparation of a predetermined amount of molten material in the operation method of the ash processing melting furnace, and FIG. FIG. 3 is an explanatory view of a state in a furnace when a salt is separated in an operation method of a melting furnace for industrial use.

As shown in FIG. 1, a melting furnace 10 for ash processing according to an embodiment of the present invention is a melting furnace body for heating, melting, separating and discharging ash 12 supplied from an ash inlet 11. 13, a vertically movable upper and lower electrode 15, 16 for supplying current to the ash 12 and the melt 14 in the melting furnace body 13,
And a power supply device 17 for supplying a single-phase AC current to the upper and lower electrodes 15 and 16. Hereinafter, these will be described in detail. In addition to the ash inlet 11 into which the ash 12 is injected, the metal outlet 19, the slag outlet 20, the salt outlet 21, and the exhaust outlet 2 are arranged above the furnace bottom 18 in order from the bottom.
2 are formed. The upper electrode 15 is made of carbon, is disposed so as to be inserted into the furnace lid 44, and is configured to be independently movable up and down by the upper electrode elevating device 23. The upper electrode 15 is appropriately cooled by a cooling system (not shown) to prevent erosion.

The lower electrode 16 is made of carbon and the upper electrode 15
And is connected to a hydraulic cylinder 24 constituting a lower electrode elevating device via an insulating holder 25 so as to face the furnace bottom. The lower electrode 16 is also cooled via a cooling water pipe 26 and a water cooling sleeve 27. Water cooling sleeve 2
The melt 14 is sealed by cooling the melt 14 with 7, and a heat-resistant packing 28 slidable with the outer surface of the lower electrode 16 and sealing the ash 12 is built in the water-cooled sleeve 27. . The power supply device 17 includes a power supply 29 for resistance heating that can adjust the voltage with a constant voltage characteristic, and a power supply 30 for an arc in which the resistance power supply 29 has a drooping characteristic.
And are provided. Reference numerals 31 to 31 in the power supply device 17
33 is a circuit breaker, 34 is an ammeter, and 35 is a voltmeter. Therefore, in the ash processing melting furnace 10, the upper and lower electrodes 15 and 16 can be arranged at arbitrary positions, and the arc power source 30 or the resistance is provided between the upper and lower electrodes 15 and 16 at arbitrary timing. The power can be supplied by switching the heating power supply 29 via the circuit breakers 31 to 33 according to the load.

Next, the operation of the method for operating the ash melting furnace according to one embodiment of the present invention using the ash melting furnace 10 will be described with reference to FIGS. Preparation of seed water (see FIG. 2) When the melting of the ash 12 is started from the state where there is no melt 14 in the melting furnace main body 13 (at the time of start-up), the upper end surface 36 of the lower electrode 16 is fixed to the furnace bottom upper surface 37. Move to the vicinity, and use the arc power source 30 of the drooping characteristic to use the upper electrode 15 and the lower electrode 16.
The ash 12 is injected from the ash inlet 11 in a state where the arc 38 is generated between the ash 12 and the ash 12 thus melted.
A predetermined amount of molten material (metal,
A seed water comprising slag and salt) 14 is formed.

The resistance between the upper and lower electrodes 15, 16 is:
The level (thickness) of the slag interposed between the upper and lower electrodes 15 and 16 and the temperature of the slag are substantially determined, but the load applied by changing the distance H between the upper and lower electrodes 15 and 16 until the seed water is formed. However, the load, that is, the position of the upper electrode 15 cannot be changed for the purpose of controlling the temperature of the melt 14 because the arc 38 becomes unstable and cuts. Eventually, by producing the melt 14 at a certain level (for example, 3 to 7 cm) or more between the upper and lower electrodes 15 and 16, the preparation of the seed water is completed. As described above, when starting up, the seed electrode is moved in a state where the lower electrode 16 is moved to the vicinity of the furnace bottom upper surface 37, so that the amount of the seed electrode to be prepared is minimized. And the running cost required for startup can be reduced.

Preparation of a predetermined amount of molten material exceeding the level of the salt outlet (see FIG. 3) At the time when the seed water is formed, the power supply device 17 switches the arc power supply 30 to the resistance heating power supply 29 having a constant voltage characteristic. And heating by resistance heating. That is, the power supply device 1
Then, the circuit breakers 31 and 33 are closed and the circuit breaker 31 is closed. By switching from arc heating to resistance heating and charging and melting the ash 12, heat convection is actively generated, and the ash 12 charged into the melting furnace body 13 is entrained into the melt 14 and melts. Efficiency increases and the level of melt 14 increases. The level of this melt 14 is
Continue resistance heating until level 1 is exceeded. In FIG. 3, reference numeral 39 denotes a main current locus, and reference numeral 40 denotes a thermal convection locus.
If the center between the lower electrodes 15 and 16 is set as a heat source near the furnace bottom upper surface 51 as in the conventional example shown in FIG. 5, the furnace bottom refractory is heated more than necessary, and the heat radiation from the furnace bottom is performed. Is promoted, which is not preferred. On the other hand, when the heat source is moved to the upper layer of the melt 53a as in the conventional example shown in FIG. 7, heat convection is weakened, which is not preferable. After the seed water is thus prepared, the upper and lower electrodes 15 and 16 are heated while performing resistance heating.
By moving the center between the furnace bottom upper surface 37 and the upper surface 43 of the melt 14 to an intermediate position, heat convection is generated, and as a result, the ash 12 put in becomes easy to be caught in the melt 14 and the melting efficiency is improved. At the same time, the running cost for producing the melt 14 up to above the salt outlet 21 can be reduced.

Separation of salt and its tapping (first and second steps, see FIG. 4) In the above, after producing a melt 14 exceeding the level of the salt outlet 21 by resistance heating, the upper electrode 15 is melted.
4 moves to the vicinity of the upper surface 43 (that is, the surface) of the lower electrode 1.
A constant distance (for example, about 2 to 3 cm) is maintained between the molten material 14 and the upper molten material 14 by resistance heating or arc heating using the arc power supply 30 (first step). As a result, the salt 41 having a low specific gravity floating on the upper portion of the melt 14 is continuously heated, the fluidity of the salt 41 is maintained, the heat convection is weakened, and the salt 41 and the slag 42 are separated by specific gravity, and Mouth 2
At the same time, most of the salt 41 is gathered at the upper part of the furnace 1, and at the same time, since the upper surface of the salt 41 does not cool and solidify, most of the salt 41 in the melting furnace body 13 is discharged from the salt outlet 21. A clean slag 42 with little remaining remains. In addition, in order to switch from the power supply 29 for resistance heating to the power supply 30 for arc, after breaking the circuit breaker 31 and turning on the circuit breaker 32,
The circuit breaker 33 is turned on.

Salt 41 gathering above the level of the outlet 21
Since the volume of the salt 12 in the melt 14 can be roughly calculated based on the components of the ash 12 to be melted, the level can be determined by converting the volume from the shape of the melting furnace body 13 to a level. Up,
The center between the lower electrodes 15 and 16 is set at a fixed distance T from the upper surface 43 of the melt 14, except for the fact that the upper surface 43 of the melt 14 is spot-likely heated to reduce thermal convection. As can be seen from the above description, since the salt 41 is filled at a certain distance (for example, 5 cm) from the upper surface 43 of the melt 14, the resistance value during that time is greatly reduced.
That is, if the resistivity between the two electrodes 15 and 16 at that time is monitored, the progress of the specific gravity separation can be known, but in practice, the resistivity of the salt 41 is too low to make the measurement difficult. If the salt 41 is discharged after a certain period of time after reaching the predetermined resistivity, it is confirmed that the salt 41 is almost completely discharged.
The relationship between the predetermined resistivity and the certain time can be generally understood.

The reason for using the arc power supply 30 is that the resistivity of the salt 41 is much smaller than that of the molten material 14 (about one thousandth of slag), so that the resistance heating power supply 29 is overloaded. For this reason, if the power supply is switched to the arc power supply 30 that can withstand the short circuit state in advance, it is not necessary to damage the equipment. As described above, after the melt 14 is formed up to the level above the salt outlet 21, the upper electrode 15 is moved to the vicinity of the upper surface 43 of the melt 14 and resistance heating or arc heating is performed. no cold mass by heat radiation, and because thermal convection is small, it is easy to gravity separation of the salt 41 is the slag 42 and weight thereof is heavy amount thereof,
The salt 41 can be separated and discharged efficiently. Therefore, a clean slag 42 can be obtained. Then, both electrodes 1
After a lapse of a predetermined time since the resistivity between 5 and 16 has become equal to or less than a predetermined value, the salt 41 in the upper layer of the melt 14 is discharged from the outlet 21.
Then, the upper electrode 15 and the lower electrode 16 are lowered, and the melt 14 is heated by resistance heating (second step).

Heating of slag and tapping of slag (third step) In order to raise the temperature of the remaining clean slag 42 to a temperature suitable for tapping by the resistance heating, as shown in FIG.
The center of the upper and lower electrodes 15 and 16, that is, the heat source is moved so as to be located between the furnace bottom upper surface 37 and the upper surface 43 of the melt 14 and switched to the resistance heating power supply 29. Thereby, the slag 42 is entirely heated by the heat convection, and the resistance heating power supply 29 provides a larger output, so that the temperature can be raised in a short time. The slag 42 monitors the slag surface temperature and the like with a general-purpose radiation thermometer or the like, and discharges the slag from the slag port 20 when the slag 42 reaches the optimum tapping temperature.

Leaving seed water for next use (fourth step) When the next batch process is to be performed, a part of slag 42 is left as seed water for next use without discharging the entire amount of slag 42. With the lower electrode 16 placed in the vicinity of the furnace bottom upper surface 37, a new amount of ash can be charged again and the melting process can be performed, leaving only an amount capable of resistance heating. This allows
It is efficient and does not waste running cost or extra time for preparing the seed water by the arc power supply 30. The tapping of the slag 42 is started in a state where the normal operation load is applied, the distance H between the lower electrodes 15 and 16 and the lower electrode 16 is moved near the furnace bottom upper surface 37, and the ammeter 34 is monitored. Then, when the contact area between the upper electrode 15 and the slag 42 decreases (that is, when the seed water becomes insufficient),
Since the current starts to drop, it is time to stop tapping in order to leave the necessary minimum seed water. The slag 42 discharged at this time has a lower salt and heavy metal concentration than before, and also has a low running cost.

Ensuring a predetermined ash processing amount By repeating the above batch processes, a desired ash processing amount can be satisfied. Complete shut down of equipment After securing the desired ash treatment volume, if the batch operation is to finish the equipment completely by tapping all of the molten material (mainly slag) as the final step, the slag is discharged after finishing the above. Before carrying out, the upper end surface 36 of the lower electrode 16 is moved to a level several cm or more higher than the upper surface of the molten material which slightly remains on the furnace bottom upper surface 37 and cools down. Since the lower electrode 16 is not affected by the slag that slightly remains on the furnace bottom upper surface 37 and cools down, the upper end surface 36 of the lower electrode 16 will be used at the next startup of the equipment.
Since there is no need to perform maintenance, startup is easy.

In the above embodiment, the heating power supply is an alternating current, but is not limited thereto, and may be a direct current.
Although the lower electrode lifting device is a hydraulic cylinder, an electric screw jack or the like may be used.
Although the stroke detection of the upper and lower electrodes has not been described, a known stroke detector can be used.

[0020]

According to the ash treatment melting furnace of the present invention, the ash processing furnace is disposed on the furnace bottom side opposite to the upper electrode movably arranged up and down, and according to the melting state of the ash supplied. Power that can be supplied by switching between a lower electrode that can be moved up and down and an arc power supply with a drooping characteristic and a resistance heating power supply that can adjust the voltage with a constant voltage characteristic according to the load state between both electrodes. Since the equipment is equipped with a supply device, the time required to melt the ash by arc heating is reduced because the lower electrode is moved to the vicinity of the upper surface of the furnace when starting up. Go down. After the seed water is created, while performing resistance heating,
By moving the center between the lower electrodes to an intermediate position between the upper surface of the furnace bottom and the upper surface of the melt, heat convection occurs, and as a result, the ash that is thrown in easily becomes entangled in the melt, thereby improving the melting efficiency. At the same time, the running cost can be reduced when the melt is formed to above the level of the spout. When the center between the upper and lower electrodes is moved to near the level of the salt outlet and arc heating or resistance heating is performed using an arc power supply, there is no cooling and consolidation due to the radiation of air from the salt, and the heat convection is small. Therefore, specific gravity separation between salt and slag becomes easy, salt can be efficiently separated and hot water can be obtained, and thus clean slag can be obtained.

In the method for operating a ash treatment melting furnace according to any one of claims 2 to 7, between the upper electrode movably arranged vertically and the lower electrode movably arranged vertically at the furnace bottom side. In the method of operating a melting furnace for ash processing, which melts ash supplied by supplying electric power, the lower electrode is arranged near the upper surface of the furnace bottom in the preparation of seed water at the time of start-up, and an arc having a drooping characteristic is used. An arc is generated between the upper electrode and the lower electrode by the power supply to melt the supplied ash, and after a predetermined amount of melt is formed, heating is performed using a resistance heating power supply having a constant voltage characteristic. The time required to melt the ash by the arc heating is shortened, and as a result, the running cost is reduced. Furthermore, after the preparation of the seed water, thermal convection of the melt is generated by resistance heating, and as a result, the ash that is thrown in becomes easy to be caught in the melt. The running cost when producing the melt to the upper part can be reduced. In particular, in the operation method of the ash treatment melting furnace according to claim 3, it is confirmed that the melt exceeds the level of the salt outlet, and the upper electrode is moved to the vicinity of the surface of the melt to be in contact with the lower electrode. Since the upper layer melt is heated by resistance or arc using an arc power supply, there is no cooling and solidification due to heat radiation of the salt, and the heat convection is small, so the salt and slag Separation of specific gravity becomes easy, and salts can be efficiently separated.

In the operation method of the ash treatment melting furnace according to the fourth aspect, the resistivity between the two electrodes becomes equal to or less than a predetermined value, and the specific gravity separation of the heavy slag and the light weight salt proceeds. After that, if the salt in the upper layer of the melt is poured out of the outlet,
Clean slag can be obtained in the furnace. Next, since the upper electrode and the lower electrode are lowered and the melt is heated by resistance heating, the slag is entirely heated by thermal convection, and the temperature can be raised in a shorter time. further,
After the slag in the melt is brought to a temperature at which the slag in the melt can be discharged by resistance heating, the slag is discharged from the slag port, so that the block of the slag port can be reliably prevented. In the method for operating the ash treatment melting furnace according to claim 5, the lower electrode is arranged near the upper surface of the furnace bottom without leaving the entire molten material, leaving only an amount capable of resistance heating, and renewing a new one. Since the ash is introduced and the melting process is performed, the running cost and the extra time required for preparing the seed water by arc heating are not wasted and the process is efficient. In the method for operating a melting furnace for ash treatment according to claim 6, the first method comprises:
Since the steps to the fourth step are repeated a required number of times, a predetermined amount of ash can be processed. In the method for operating a ash treatment melting furnace according to claim 7, when the entire amount of the molten material is discharged,
Since the upper end surface of the lower electrode is located a predetermined distance above the upper surface of the molten material that slightly remains on the furnace bottom and cools down, there is no need to maintain the upper end surface of the lower electrode at the next startup of equipment. , The start-up becomes easy.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an ash processing melting furnace to which an operation method of an ash processing melting furnace according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory view of the inside of a furnace at the time of preparing a seed bath in the method for operating the ash processing melting furnace.

FIG. 3 is an explanatory view of the inside of the furnace from the preparation of a seed bath to the preparation of a predetermined amount of molten material in the method for operating the ash processing melting furnace.

FIG. 4 is an explanatory view of the inside of the furnace when the salt is separated in the method of operating the ash processing melting furnace.

FIG. 5 shows a conventional method of operating a melting furnace for ash treatment,
It is explanatory drawing in the case of fixing and operating a lower electrode near the furnace bottom upper surface.

FIG. 6 is an explanatory view in a case where the lower electrode is operated at a position slightly higher than the furnace bottom upper surface.

FIG. 7 is an explanatory diagram in a case where the lower electrode is fixed to a vicinity of a salt outlet and operated.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Ash melting furnace 11 Ash inlet 12 Ash 13 Melting furnace main body 14 Melt 15 Upper electrode 16 Lower electrode 17 Power supply device 18 Furnace bottom 19 Metal outlet 20 Slag outlet 21 Salt outlet 22 Exhaust port 23 Upper electrode Lifting device 24 Hydraulic cylinder 25 Insulating holder 26 Cooling water pipe 27 Water cooling sleeve 28 Heat resistant packing 29 Resistance heating power supply 30 Arc power supply 31 Circuit breaker 32 Circuit breaker 33 Circuit breaker 34 Ammeter 35 Voltmeter 36 Upper end surface 37 Furnace bottom upper surface 38 Arc 39 Main current locus 40 Heat convection locus 41 Salt 42 Slag 43 Upper surface 44 Furnace lid

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F27D 11/08 B09B 3/00 303L (72) Inventor Sadaharu Hara 46-59 Ohara Nakahara, Tobata-ku, Kitakyushu, Fukuoka Prefecture Nippon Steel Corporation Engineering Business Division (72) Inventor Shinji Iwamoto 46-46 Nakahara, Tobata-ku, Kitakyushu-shi, Fukuoka 59 Nippon Steel Plant Design Co., Ltd. (72) Inventor Shuichi Matsumoto Nakahara, Tobata-ku, Kitakyushu-shi, Fukuoka 46 No. 59 Nippon Steel Plant Design Co., Ltd. F term (reference) 3K061 BA05 NB02 NB30 4K045 AA04 BA07 DA02 RB02 RB04 4K063 AA04 AA12 BA13 CA01 CA02 FA55 FA64 FA73 FA78

Claims (7)

[Claims] An upper electrode movably arranged up and down, and an upper electrode arranged on a furnace bottom side opposite to the upper electrode, and movably arranged up and down according to a melting state of ash inputted. A lower electrode, and a power supply device capable of supplying power by switching between a power supply for arc having a drooping characteristic and a resistance heating power supply capable of adjusting a voltage with a constant voltage characteristic according to a load state, between the two electrodes. Melting furnace for ash treatment. 2. An ash process for supplying electric power between an upper electrode movably arranged vertically and a lower electrode movably arranged vertically at the furnace bottom side to melt ash supplied. In the method for operating a melting furnace for use, at the time of startup, the lower electrode is disposed near the upper surface of the furnace bottom,
An arc power supply with a drooping characteristic generates an arc between the upper electrode and the lower electrode to melt the ash that has been thrown in, and after a predetermined amount of melt is formed, a constant-voltage characteristic resistance heating power supply A method for operating a melting furnace for ash treatment, characterized by heating using ash. 3. Confirming that the melt has exceeded the level of the salt outlet, moving the upper electrode to a position near the surface of the melt and keeping a constant distance from the lower electrode, The method for operating a ash treatment melting furnace according to claim 2, wherein the upper layer of the melt is resistance-heated or arc-heated using the arc power supply. 4. After the resistivity between the two electrodes becomes equal to or less than a predetermined value and the specific gravity of slag, which is a heavy material, and salt, which is a light material, proceed, the salt in the upper layer of the melt is discharged. The molten metal is heated from the salt port, then the lower electrode and the lower electrode are lowered, and the melt is heated by resistance heating. The method for operating a melting furnace for ash treatment according to claim 3, wherein the hot water is discharged from a mouth. 5. The molten metal is not poured in its entirety, the lower electrode is arranged near the furnace bottom upper surface, the amount capable of resistance heating is left, fresh ash is charged again, and the melting process is performed. The method for operating a ash treatment melting furnace according to claim 4. 6. Confirming that the melt has exceeded the level of the salt outlet, moving the upper electrode to a position near the surface of the melt and maintaining a constant distance between the lower electrode and the lower electrode, A first step of resistance-heating or arc-heating the upper layer of the melt using the arc power supply; and a resistivity between the two electrodes being a predetermined value or less, a heavy slag and a light weight. After the specific gravity separation of the salt has progressed,
Tapping the salt in the upper layer of the melt from the salt outlet,
A second step of lowering the upper electrode and the lower electrode and heating the melt by resistance heating; and setting the slag in the melt to a temperature at which tapping can be performed by the resistance heating, and then discharging the slag from the slag port. 3. The method for operating an ash treatment melting furnace according to claim 2, wherein three steps and a fourth step of re-feeding new ash while leaving the slag amount capable of resistance heating are repeated a required number of times. 7. As a final step, when the entire amount of the molten material is discharged, the upper end surface of the lower electrode is disposed at a position higher than the upper surface of the molten material that slightly remains on the upper surface of the furnace bottom by a predetermined distance. An operating method of the melting furnace for ash treatment according to claim 6.