JP2896562B2 - Waste melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste melting furnace for melting waste, for example, a municipal solid waste incinerator,
Incineration ash discharged from sludge incinerators and industrial waste furnaces, fly ash generated during incineration of these, and a mixture of these incineration ash and fly ash are melted by adding additives to reduce volume. The present invention relates to a waste melting furnace for melting and processing a regenerated product for detoxifying and reusing a molten material.

[0002]

2. Description of the Related Art Conventionally, for example, a coke bed melting furnace, a surface melting furnace, a swirling flow melting furnace, and the like are used to melt and solidify incineration ash discharged from a municipal solid waste incinerator to reduce the volume and render it harmless. Electric melting furnaces such as a fuel-fired melting furnace, a plasma melting furnace, an electric arc furnace, an electric resistance furnace, and a microwave melting furnace are used.

[0003] Here, as a fuel-fired melting furnace, for example, Japanese Patent Laid-Open No. 6-11127 (hereinafter referred to as a first conventional example).
And Japanese Patent Application Laid-Open No. 7-294156 (hereinafter referred to as a second conventional example) and Japanese Patent Application Laid-Open No. 7-49185 (hereinafter referred to as a third conventional example). Some are described in

In the first conventional example, an ash melting furnace for heating and melting ash with a heating burner is provided by a preheating chamber formed in a furnace main body and a melting chamber provided with a heating burner communicating with the preheating chamber. An ash melting furnace is described in which ash is supplied from a hopper for storing ash to a melting chamber through a preheating chamber, is heated and melted by a heating burner, and is then solidified in a cooling bath.

The second conventional example has a dish-shaped furnace main body and a furnace lid attached to the upper surface thereof, and a molten slag discharge port opened in the upper and lower central portions of the furnace main body, and a furnace lid is provided. A three-phase AC arc furnace equipped with an electrode inserted in the inside, a waste inlet, an air supply port, and a waste port opened in the furnace lid, and a molten slag air cooling device connected to the molten slag discharge port There is disclosed a waste melting treatment apparatus having the following.

In the third prior art, a furnace body having an upper opening provided with a power supply electrode, an upper resistance heating element and a lower resistance heating element which are filled inside the furnace body in a vertically stacked state are disclosed. The upper layer resistive heating element is constituted by a powdery material obtained by crushing and classifying a kneaded and baked material of carbonized fine particles and an inorganic heat resistant material that becomes conductive at a predetermined temperature or higher, and the lower layer resistive heating element includes: There is described an electric resistance heating furnace composed of carbon granules having an average particle size of 1 mm to 5 mm obtained by crushing and classifying charcoal and the like, and performing high-temperature heating at about 3000 ° C. by energizing these resistance heating elements. .

[0007]

However, in the ash melting furnace of the first conventional example, the ash is preheated while being moved, and then melted by the heating burner. If it is too fast, ash exceeding the melting capacity of the heating burner will be carried into the melting chamber, the ash residence time in the melting chamber will not be sufficient, and unmelted ash will be discharged, and will be put into the melting furnace again. There is a problem that it has to be done again. Also, the unmelted ash may block the discharge port, forcing the furnace operation to stop. Furthermore, the ash may stick during the transfer of the ash from the hopper to the melting chamber. Due to these problems, there is a problem that the operating efficiency of the furnace as a whole is reduced.

Further, in the second conventional example, since the furnace main body is dish-shaped, the installation area is large, and it is not preferable from the viewpoint of energy efficiency. Is discharged by
It is inevitable that a small amount of insoluble matter is mixed in when the molten material is discharged, and there is an unsolved problem such as a great problem in reusing the molten slag.

Further, in the third conventional example, since the upper layer resistance heating element and the lower layer resistance heating element constitute a high-temperature heat source, the temperature around the heating element becomes locally high and the refractory It is necessary to repair the meltdown, which causes a problem that the operation rate is reduced.
In addition, there is also a problem that the substance which is a main component is evaporated, the amount of dust generated in the melting process increases, and the processing cost increases. Furthermore, if the electrode portion becomes a high-temperature heat source, a large amount of cooling water is used, and the amount of heat carried by the cooling water increases, resulting in a problem that energy efficiency is reduced.

On the other hand, in such a conventional apparatus, a large amount of exhaust gas such as air for melting ash or the like, a carrier gas, and a gas generated by the reaction between the electrode and the air becomes large, so that secondary pollution is generated or the exhaust gas is treated. Has become a problem.

Therefore, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and has been made to reduce the amount of exhaust gas, prevent the refractory from being melted by local heating, and further reduce the energy consumption. It is an object of the present invention to provide a waste melting furnace capable of improving efficiency, reducing the size of the entire apparatus, and facilitating recycling of molten slag.

[0012]

In order to achieve the above object,
The waste melting furnace according to claim 1 includes a furnace main body having an open upper end, and a furnace lid for opening and closing the upper end of the furnace main body, and the furnace main body is disposed at a central portion thereof. A vertical crucible, a refractory brick layer having a rectangular cross section surrounding the vertical crucible with a predetermined space therebetween, and supported by penetrating the refractory brick layer on the inner peripheral surface of the refractory brick layer in a crossbeam shape. A heat generating electrode disposed therein, an inert gas inlet formed in a support portion of the heat generating electrode, and a melt discharge unit having an auxiliary heating mechanism and a flow rate adjusting mechanism disposed at a lower side of the vertical crucible; A raw material supply mechanism for supplying a molten raw material to the vertical crucible disposed on the side surface of the furnace lid, and an exhaust gas discharge unit disposed on the upper surface side and the raw material supply mechanism are charged into the vertical crucible. And a stirring mechanism to forcibly immerse the molten material into the melt And it features.

In the invention according to the first aspect, the molten raw material is charged into the vertical crucible and heated by the heating electrodes arranged in a grid around the crucible, so that the energy efficiency is improved and the generated exhaust gas is reduced. Since the exhaust gas is discharged from the exhaust gas discharge portion formed at the upper part of the furnace lid, the exhaust gas can be quickly discharged, and the erosion of the refractory brick or the like can be prevented.

Further, since the inert gas inlet is formed in the supporting portion of the heat generating electrode, the inert gas flows around the heat generating electrode from the inlet, and the upper portion of the outer peripheral portion of the vertical crucible has a positive pressure higher than the atmospheric pressure. The pressure can be maintained and the oxidation of the heating electrode can be prevented, while the erosion of the refractory brick by the exhaust gas can be prevented and the durability of the waste melting furnace can be improved. For this reason, the amount of exhaust gas can be reduced by using only the exhaust gas generated from the raw material as the exhaust gas amount, and the amount of dust carried away by the exhaust gas amount can be reduced. The gas composition can be reduced, and the occurrence of secondary pollution can be suppressed.

Further, since the discharge port for the molten material in the vertical crucible is provided at the lower side of the vertical crucible, the molten material can be smoothly discharged to the outside of the furnace without mixing insoluble materials. Quantification is possible, and recycling can be achieved.

Furthermore, since the raw material stirring mechanism is provided, it is possible to improve the melting speed of the input raw material without increasing the temperature near the inner surface of the vertical crucible, and to reduce the size of the waste melting furnace. Can be.

According to a second aspect of the present invention, there is provided the waste melting furnace according to the first aspect, wherein the molten material discharge portion is provided with an inert gas inlet for preventing air from entering. Features.

According to the second aspect of the present invention, an inert gas is also introduced into the melt discharge portion, thereby reliably preventing air from entering the discharge portion, thereby forming a discharge nozzle or the like constituting the discharge portion. Oxidation of the constituent devices can be reliably prevented, and the durability can be improved.

Further, the waste melting furnace according to claim 3 is characterized in that, in the invention according to claim 1 or 2, the melt discharge part is communicated with a lowermost side surface of a vertical crucible. I do.

According to the third aspect of the present invention, since the melt discharge portion is communicated with the lowermost side surface of the vertical crucible, it is possible to smoothly discharge the melt without mixing insoluble matter into the melt. it can.

Further, in the waste melting furnace according to claim 4, in the invention according to any one of claims 1 to 3, the stirring mechanism is capable of changing a set position and has a stirring stroke in a range of 0 to 500 mm. And the time required for one stirring stroke can be adjusted within a range of 10 to 60 seconds.

According to the fourth aspect of the present invention, proper melting can be performed by suppressing the temperature rise near the inner surface of the vertical crucible while improving the speed of dissolving the raw material into the melt by the stirring mechanism.

Still further, a waste melting furnace according to claim 5 comprises:
In any one of the inventions according to Claims 1 to 4, the molten raw material supplied by the raw material supply mechanism is incinerated ash of general waste,
Fly ash, industrial waste cinders, organic sludge, inorganic sludge,
It is characterized by being prepared by adding an additive to any one of coal ash and the like or a mixture thereof.

[0024] In the invention according to claim 5, the additive is added to one or a mixture of incinerated ash of general waste, fly ash, cinder of industrial waste, organic sludge, inorganic sludge, coal ash and the like. Can be reliably melt-processed.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a waste melting furnace according to the present invention will be described in detail with reference to the drawings. 1 and 2 are a longitudinal sectional view and a transverse sectional view showing an embodiment of the present invention.

In the figure, reference numeral 1 denotes a waste melting furnace, which comprises a furnace main body 2 having a bottomed rectangular cylindrical shape and having an open upper surface, and a furnace lid 3 for opening and closing the upper surface.

The furnace body 2 has a rectangular cylindrical outer cover 4 having a rectangular cross section.
And a refractory brick layer 5 made of SiC disposed on the inner peripheral surface and the lower end surface thereof, and supported at a predetermined distance from a lower end position to a lower end side at a predetermined distance from an upper end inside the refractory brick layer 5 to form a girder shape A heating electrode 6 composed of 3 × n (n is a positive integer) resistance heating elements,
And a cylindrical vertical crucible 7 having an upper end disposed close to the inside thereof and flush with the upper end of the furnace main body 2.

Here, as shown in FIG. 2, both ends of the heating electrode 6 are supported by a power introduction supporting portion 8 formed on the outer cover 4 through the refractory brick layer 5.
Are sealed by the support cap 9.

Each of the heating electrodes 6 is connected as a set of three via a power introduction supporting portion 8 in a star connection or a Δ connection.
These are connected to a three-phase AC power supply (not shown) via a power switch.

Further, the refractory brick layer 5 in which the space portion of the power introduction supporting portion 8 and the heating electrode 6 are disposed, and the vertical crucible 7
An inert gas such as a nitrogen gas is supplied from an inert gas inlet 10 formed in a lower portion of the outer cover 4 to a space between the inert gas and the space.
The pressure in all the spaces including the heating electrode 6 is pressurized so that the pressure becomes higher than the pressure on the upper side thereof, that is, the pressure above the upper end of the vertical crucible 7. Intrusion into the heating electrode 6 and the refractory brick layer 5 is reliably prevented.

Further, a melt discharge mechanism 12 penetrating the outer shell 4 and the refractory brick layer 5 is provided on the lowermost side surface of the vertical crucible 7.
Is communicated.

The melt discharge mechanism 12 is provided with a vertical crucible 7.
A melt nozzle 13 having one end inserted therein, a flow control unit 14 provided at the other end of the melt nozzle 13 for controlling the opening area thereof to control the flow rate, and a melt flowing down from the flow control unit 14 The receiving tray 15 is provided with a tap opening 17 which is inserted into a downflow passage 16 extending downward in communication with the receiving tray 15.

Here, an auxiliary heater 19 is wound outside the furnace body 2 of the molten metal nozzle 13 as shown in FIG. 2, and the auxiliary heater 19 can smoothly and quantitatively fix the melt without solidifying it. Can be discharged in a state.

An inert gas inlet 18 is communicated with the downflow passage 16 to introduce an inert gas such as nitrogen gas, thereby preventing air from entering from the tap port 17.

On the other hand, a circular recess 21 having a diameter equal to the inner diameter of the furnace lid 3 is formed at the lower end face of the furnace lid 3 so as to face the vertical crucible 7. A raw material supply mechanism 22 is provided so as to pass therethrough, and a stirring mechanism 23 is provided at an upper position opposite to the opening of the raw material supply mechanism 22. 3, an exhaust gas discharge passage 25 having a pressure regulating valve 24 is communicated therewith.

Here, the pressure regulating valve 24 has a furnace internal pressure of 10
The pressure can be adjusted to ５０50 mmH ₂ O, and the inside of the circular recess 21 is maintained at a positive pressure.

The raw material supply mechanism 22 includes an upper raw material supply path 2
6 and a raw material hopper 28 for storing the molten raw material supplied through the upper slide valve 27;
Screw feeder 30 connected to the lower end of a lower slide valve 29 disposed at the cutout at the lower end of the fixed screw feeder 30
And

The bottom side wall of the hopper 28 communicates with an inert gas inlet 31 for removing air introduced by the molten raw material with an inert gas.
Is closed and the inert gas such as nitrogen gas is introduced from the inert gas inlet 31 with the upper slide valve 27 opened, whereby the air in the hopper 28 can be replaced with the inert gas.

The molten raw material supplied through the raw material supply path 26 may be any one of incinerated ash from general waste, fly ash, cinders from industrial waste, organic sludge, inorganic sludge, coal ash and the like. The mixture was prepared by adding additives to the mixture.

Further, the stirring mechanism 23 is provided so that the set position with respect to the furnace lid 3 can be changed, and is provided with an actuator 36 which is sealed by a seal member 35 and includes a drive roller or the like connected to a drive source such as an electric motor. It has a stirring rod 38 that is driven to reciprocate up and down.

The stirring rod 38 can be adjusted so that its stirring stroke is in the range of 0 to 500 mm, and the time required for one stirring stroke can be set in the range of 10 to 60 seconds.

The above is the configuration showing an example of the embodiment of the present invention. Next, the operation will be described. Now, a predetermined amount of the molten raw material is charged into the raw material hopper 28, and while the inside thereof is filled with the inert gas from the inert gas inlet 31, the lower slide valve 29 is opened to open the raw material supply mechanism 22.
The fixed amount of the molten raw material is injected into the melt in the vertical crucible 7 by the fixed screw feeder 30.

At this time, the heating electrode 6 is supplied with three-phase alternating current from a three-phase alternating current source, is in a heating state, and heats the vertical crucible 7 to a predetermined temperature to melt the molten material to be charged. Let me.

The molten material thus introduced floats on the melt, but the stirring rod 38 of the stirring mechanism 23 is reciprocated in the vertical direction at the position where the molten material is dropped. The molten material introduced by the rod 38 is immersed in the melt to improve the melting efficiency.

Further, the melt which has stayed in the vertical crucible 7 for a long time and has been completely melted is flow-adjusted by the flow adjusting section 14 through the melt nozzle 13 of the melt discharge mechanism 12 provided below the vertical crucible 7. In addition, the insoluble matter is discharged through the tap port 17 without mixing.

At this time, since the charged molten raw material stays in the vertical crucible 7 for a long time, most of the harmful substances contained in the molten raw material evaporate and are contained in the exhaust gas. Since it is discharged out of the system through 25 and collected, impurities are surely prevented from being mixed into the discharged molten material, and the molten material can be reused.

The melt discharged from the vertical crucible 7 is supplied to an auxiliary heater 19 wound around the melt nozzle 13.
As a result, the solid is discharged smoothly without being solidified, and the periphery of the tray 15 and the molten metal nozzle 13 is filled with the inert gas from the inert gas inlet 18. To prevent oxidation of the melt discharge mechanism 12 to improve durability.

Further, the heating electrode 6 and the refractory brick layer 5 arranged around the vertical crucible 7 of the furnace main body 2 are heated by the inert gas supplied from the inert gas inlet 10 to the vertical crucible 7. Since the upper side is maintained so as to have a positive pressure in comparison with the upper side, exhaust gas generated in the vertical crucible 7 is reliably prevented from entering the space including the heating electrode 6. Oxidation and erosion of the refractory brick layer 5 can be prevented, and the durability of the furnace body 2 can be greatly improved as compared with the conventional example.

In the above embodiment, the case where the melt discharge mechanism 12 is communicated with the lowermost side wall of the vertical crucible 7 has been described. However, the present invention is not limited to this. Alternatively, the melt discharge mechanism 12 may be communicated with a position below the central portion in the vertical direction where no insoluble matter is mixed therein.

In the above embodiment, the case where the fixed screw feeder 30 is applied to the raw material supply mechanism 22 has been described. However, the present invention is not limited to this, and the fixed feed is performed by applying a rotary feeder. Alternatively, a belt feeder may be applied.

[0051]

As described above, according to the first aspect of the present invention, the molten raw material is charged into the vertical crucible and is heated by the heating electrodes arranged in a grid around the crucible. In addition to the improvement, the generated exhaust gas is discharged from the exhaust gas discharge portion formed at the upper part of the furnace lid, so that it is possible to obtain an effect that the exhaust gas can be quickly discharged and erosion of refractory bricks and the like can be prevented. .

Further, since the inert gas inlet is formed in the supporting portion of the heating electrode, the inert gas flows around the heating electrode from this inlet, and the upper portion of the outer peripheral portion of the vertical crucible is positively charged at a pressure higher than the outside pressure. The pressure can be maintained and the oxidation of the heating electrode can be prevented, while the erosion of the refractory brick by the exhaust gas can be prevented and the durability of the waste melting furnace can be improved. For this reason, the amount of exhaust gas can be reduced by using only the exhaust gas generated from the raw material as the exhaust gas amount, and the amount of dust carried away by the exhaust gas amount can be reduced. The gas composition can be reduced, and the occurrence of secondary pollution can be suppressed.

Further, since the discharge port for the molten material in the vertical crucible is provided at the lower side of the vertical crucible, the molten material can be smoothly discharged to the outside of the furnace without mixing insoluble materials. Quantification is possible, and recycling can be achieved.

Further, since the raw material stirring mechanism is provided, it is possible to improve the melting speed of the input raw material without increasing the temperature near the inner surface of the vertical crucible, and to reduce the size of the waste melting furnace. Can be.

According to the second aspect of the present invention, by introducing an inert gas into the melt discharge portion, the intrusion of air from the discharge portion is reliably prevented, thereby forming the discharge portion constituting the discharge portion. Oxidation of components such as nozzles can be reliably prevented, and durability can be improved.

Further, according to the third aspect of the present invention, since the molten material discharging portion is communicated with the lowermost side surface of the vertical crucible, the molten material is smoothly discharged without mixing insoluble material. be able to.

Furthermore, according to the fourth aspect of the present invention,
Appropriate melting can be performed by suppressing the temperature rise near the inner surface of the vertical crucible while increasing the rate of dissolution of the input raw material into the melt by the stirring mechanism.

Further, according to the invention of claim 5, any one of incinerated ash of general waste, fly ash, cinder of industrial waste, organic sludge, inorganic sludge, coal ash and the like, or a mixture thereof. Can be reliably melt-processed by adding additives.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a waste melting furnace according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Waste melting furnace 2 Furnace main body 3 Furnace lid 5 Refractory brick layer 6 Heating electrode 7 Vertical crucible 8 Power introduction support part 10 Inert gas introduction port 12 Melt discharge mechanism 13 Melt nozzle 14 Flow rate adjustment part 17 Tap opening 18 Non Active gas introduction port 19 Auxiliary heater 22 Raw material supply mechanism 23 Stirring mechanism 25 Exhaust gas discharge path 26 Raw material supply path 27 Upper slide valve 28 Raw material hopper 29 Lower slide valve 30 Fixed screw feeder 31 Inert gas introduction port 36 Actuator 38 Stir rod

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-10-47642 (JP, A) JP-A-4-55687 (JP, A) JP-A-7-171536 (JP, A) JP-A-62 288412 (JP, A) JP-A-8-28837 (JP, A) Japanese Utility Model Application Laid-Open No. 55-96400 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F23J 1/00 F23G 5 / 00 F23G 5/24-5/28 F23G 7/00 F23J 1/08 F27D 11/02

Claims (5)

(57) [Claims] A furnace body having an open upper end; and a furnace lid for opening and closing the upper end of the furnace body, wherein the furnace body has a vertical crucible disposed at a central portion thereof; A refractory brick layer having a rectangular cross section surrounding the vertical crucible with a predetermined space therebetween, and a heating electrode disposed in a cross-shaped manner supported by penetrating the refractory brick layer on the inner peripheral surface of the refractory brick layer. An inert gas inlet formed in a support portion of the heating electrode; and a melt discharge portion having an auxiliary heating mechanism and a flow rate adjusting mechanism disposed on a lower side of the vertical crucible, The lid has a raw material supply mechanism that supplies the molten raw material to the vertical crucible disposed on the side surface, an exhaust gas discharge unit disposed on the upper surface side, and the molten raw material charged into the vertical crucible inside the molten material. And a stirrer mechanism for forcibly immersing in the wastewater. Melting furnace. 2. The waste melting furnace according to claim 1, wherein an inert gas inlet for preventing air from entering is formed in the melt discharge part. 3. The waste melting furnace according to claim 1, wherein the melt discharge portion communicates with a lowermost side surface of the vertical crucible. 4. The stirring mechanism is configured such that a set position can be changed, a stirring stroke can be adjusted within a range of 0 to 500 mm, and a time required for one stirring stroke can be adjusted within a range of 10 to 60 seconds. The waste melting furnace according to any one of claims 1 to 3, wherein: 5. The molten raw material supplied by the raw material supply mechanism may be any one of incinerated ash from general waste, fly ash, cinders from industrial waste, organic sludge, inorganic sludge, coal ash and the like. The waste melting furnace according to any one of claims 1 to 4, wherein the mixture is prepared by adding an additive to the mixture.