JPH0694927B2 - Plasma incinerator ash melting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to plasma incineration in which incineration ash generated by incinerating municipal waste, sewage sludge, or other waste in an incinerator is melted in a melting furnace. It relates to an ash melting device.

[Conventional technology]

In general, incinerator ash generated by incinerating municipal solid waste, sewage sludge, or other wastes in a waste incinerator is currently landfilled in most cases.
However, since it is becoming more difficult to secure landfill sites year after year, there is a demand for a method of reducing the volume of incinerated ash to be landfilled, that is, volume reduction treatment.

If the incinerated ash itself is landfilled in a landfill without being treated, the incinerated ash itself contains harmful substances such as various heavy metals. And the like, or the unburned organic substances in the incinerated ash are decomposed, and these phenomena cause secondary pollution. Therefore, there is a demand for pollution-free treatment of incineration ash discharged from the incinerator.

For this reason, various treatment methods for incinerated ash have been conventionally developed. For example, a treatment method of mixing incineration ash with cement to solidify the incineration ash with cement, a treatment method of mixing with asphalt to solidify the incinerator ash, or a treatment method of mixing the incineration ash with clay or the like to sinter and solidify the incineration ash. Is disclosed.

However, these treatment methods have problems that the treatment cost is high and that the treatment state of the incineration ash lacks technical reliability.

Another method for treating the incinerated ash is a method of melting the incinerated ash by charging the incinerated ash in a burner furnace, an electric furnace, that is, an open arc furnace. For example, as a processing method using an open arc furnace for steelmaking, there is one disclosed in Japanese Patent Laid-Open No. 52-86976.

The combustion and melting method of the sludge is performed by charging the sludge in a closed arc furnace in which an arc is constantly generated between an electrode and a molten metal, and the organic matter in the sludge is decomposed by the arc heat of the arc to form a gas in a furnace. The inorganic substances in the sludge are melted by the arc heat of the arc and melted into the molten metal or taken out of the furnace as molten slag.

Alternatively, JP-A-55-114383 discloses a method for melting incinerated ash. The melting treatment method of the incineration ash,
The incineration ash is sequentially charged onto the molten slag in the submerged arc furnace to form an incineration ash layer, and the incineration ash in the incineration ash layer is sequentially melted by electric resistance heat of the molten slag. In this case, as the incineration ash, a mixed ash of ash that is incinerated and discharged in the incinerator and dust ash that is collected in the dust collector is used.

[Problems to be Solved by the Invention]

However, since the sludge combustion and melting method disclosed in JP-A-52-86976 uses an open arc furnace using a graphite electrode, a sufficient high temperature cannot be obtained, and therefore the incineration ash is not obtained. In particular, the incineration ash of municipal waste has a problem in that it cannot completely melt the high melting point substances such as earth and sand, pottery, and metals contained therein. Therefore,
Since only a substance that can be melted in the open arc furnace is charged into the open arc furnace, the high melting point substance is preliminarily selected from the incinerator and then charged into the furnace, or a melting point depressant such as lime or fluorite. Had to be added to the incineration ash for melt processing.

Further, in the open arc furnace, in order to generate an arc between the electrode and the molten metal, in order to treat waste such as incinerated ash, which is mainly composed of an oxide contained as a slag component, It is necessary to melt a metal such as iron in a furnace in advance to prepare a so-called base metal.

Furthermore, when incinerated ash with a non-uniform composition such as oxide is put on the base metal, the fluctuation of the arc power is large, and
The phenomenon that the arc disappeared occurred. Moreover, when the arc is extinguished, the incinerated ash that has no electrical conductivity is covered on the base metal, and the incinerated ash is processed again.Therefore, there is often a problem that the incinerated ash cannot be re-ignited. occured.

Further, in the case of a burner furnace, a higher temperature cannot be obtained than in an open arc furnace, and since a large amount of fuel combustion air is used, the amount of exhaust gas becomes enormous, and as a result, a large-scale exhaust gas treatment device is required. The problem arises.

Generally, plasma is a state in which electrons are ejected from atoms to be ionized, which is high energy generated when electrons are ejected from atoms, and the vicinity of plasma is a high temperature atmosphere. A plasma arc furnace is provided for generating a plasma. A plasma torch is provided in the plasma arc furnace. Further, the incinerated ash generated from the incinerated ash and the combustion exhaust gas are cleaned by a dust collector such as an electric dust collector, and the cleaned exhaust gas is discharged from the chimney through the induction fan.

Therefore, an object of the present invention is to solve the above problems, regardless of the type and composition of the incineration ash, for example, even if the incineration ash contains a high melting point substance such as metal ware, earth and sand, Without removing the high melting point substances from the incineration ash in advance, the incineration ash is directly charged into the melting furnace, plasma is generated using a plasma torch which is a plasma generator provided in the melting furnace, and the plasma is generated. The incineration ash is melted by the high energy of and the incineration ash is always treated stably.
A plasma incinerator ash melting apparatus comprising a furnace lid in a fixed state and a furnace body that can be easily and quickly attached to and detached from the furnace lid, and can easily discharge the residual molten slag in the furnace body. Is to provide.

[Means for Solving the Problems]

The present invention is configured as follows to achieve the above object. That is, the present invention provides a furnace lid fixedly provided with an incinerator ash supply port and an exhaust gas outlet, a plasma torch provided on the furnace lid so as to be able to move up and down and tilt with respect to the furnace lid, and the furnace. A furnace body made of a refractory material that can be attached to and removed from the lid and has a slag discharge port, a truck equipped with the furnace body that moves the furnace body with respect to the furnace lid,
The furnace body can be moved up and down with respect to the furnace lid so that the furnace body can be attached to and detached from the furnace lid, and the furnace body can be tilted to discharge the residual molten slag in the furnace body. The present invention relates to a plasma incineration ash melting apparatus having a vertical movement and tilting mechanism provided on a trolley, and a hood with an exhaust gas outlet provided at the slag discharge port.

Further, this plasma incineration ash melting apparatus is provided at the bottom of the furnace body from the counter electrode of the plasma torch.

Further, in this plasma incineration ash melting apparatus, the vertical movement and tilting mechanism includes a hydraulic jack attached to the truck for raising the furnace body, the furnace body and the truck for tilting the furnace body. And a hydraulic cylinder mounted between the and.

[Action]

The plasma incineration ash melting apparatus according to the present invention is configured as described above and operates as follows. That is, this plasma incineration ash melting apparatus is installed in a fixed state and has a furnace lid having an incinerator ash supply port and an exhaust gas outlet, is tiltably attached to the carriage, and is vertically movable with respect to the furnace lid and is removable. Since it is composed of a furnace body attached to the furnace and having a slag discharge port, and a plasma torch attached to the furnace lid, a plasma arc can be continuously and stably obtained by the plasma torch, and the thermal energy of high-temperature plasma can be obtained. Therefore, even if the incineration ash of the high melting substance is directly put into the melting furnace, it can be quickly melted.

Further, since the plasma torch is attached to the furnace lid so as to be able to move up and down and tilt, the plasma torch can be brought close to the counter electrode and the plasma arc can be ignited.

Furthermore, since the molten slag in the furnace body is continuously discharged to the outside of the furnace by overflow from the slag discharge port, the incineration ash can be sequentially or continuously charged into the melting furnace, and the incineration ash is continuously melted. be able to.

In particular, since the carriage is provided with the vertical movement and tilting mechanism, the furnace body can be moved up and down with respect to the furnace lid so that the furnace body can be attached to and detached from the furnace lid, and the remaining inside the furnace body The furnace body can be tilted to discharge the molten slag, and therefore, at the end of the melting operation, the furnace body is lowered from the furnace lid to move the furnace body by the carriage,
Then, the furnace body is tilted so that the residual molten slag in the furnace body can be easily and surely discharged to the outside of the furnace body.

Furthermore, since the hood with an exhaust gas outlet is provided at the slag discharge port, the exhaust gas is smoothly discharged from the exhaust gas outlet in the upper part of the furnace body through the induction fan from the hood with an exhaust gas outlet. Further, the slag can be maintained at a high temperature, and cooling and solidification at the slag discharge port can be prevented.

〔Example〕

An embodiment of a plasma incineration ash melting apparatus according to the present invention will be described below with reference to the drawings.

The plasma incineration ash melting apparatus according to the present invention mixes incineration ash generated by incinerating waste or the like from an incinerator, and in some cases, dust or incineration ash collected by the dust collector in the incinerator system. Then, it is put into a melting furnace, that is, a plasma arc furnace, and the incinerator ash is melted in the plasma arc furnace.

FIG. 1 shows this plasma incineration ash melting apparatus. This plasma incineration ash melting apparatus melts incinerator ash generated by incinerating municipal waste, sewage sludge, or other waste in an incinerator in a melting furnace, that is, a plasma arc furnace 5, and mainly uses plasma. It comprises an arc furnace 5, a plasma torch 8 provided in the plasma arc furnace 5, and a plasma system 1 for generating plasma in the plasma torch 8.

The plasma torch 8 used in this plasma incineration ash melting apparatus uses a transfer type or a non-transfer type as an arc discharge type.

As shown in FIG. 1, the plasma arc furnace 5 includes a furnace body 6
A water-cooled fixed-type furnace lid 7 that is the upper part of the furnace is provided. The furnace body 6 is constructed of a refractory material such as carbon, magnesia, or alumina, and is mounted on a carriage 2 that can run on a rail 3. The furnace body 6 is tilted with respect to the carriage 2 by a vertically moving and tilting mechanism provided on the carriage 2 to be described later. It is possible to move up and down with respect to the furnace lid 7, that is, to move up and down.

Therefore, the furnace body 6 can be attached to the furnace lid 7 that is fixedly installed by raising the furnace body 6, and the furnace body 6 can be attached.
The residual molten slag accumulated in the furnace body 6 can be discharged by the tilting.

Further, the furnace lid 7 is provided with a torch lifting device 11, an incineration ash charging chute 9 and an exhaust gas exhaust gas duct 23. The plasma torch 8 is installed on the furnace lid 7 by a torch lifting device 11. Further, when a plasma arc torch type of transfer type is used as the plasma torch 8 as shown in FIG. 2, a graphite electrode serving as a counter electrode 10 of the plasma torch 8 is embedded in the bottom of the furnace body 6. To configure.

When the transfer type plasma torch 8 is used in the plasma arc furnace 5 as described above, an electrode (+ electrode) built in the plasma torch 8 and a graphite electrode provided on the bottom of the furnace body 6 are used. A plasma arc is generated between a certain counter electrode 10 (-pole). The generation of plasma in the plasma torch 8 is achieved by the operation of the plasma system 1.

The plasma system 1 mainly includes a plasma torch 8 of a transfer type or a non-transfer type, a power supply device 4 for switching an alternating current to a direct current and supplying a direct current to the plasma torch 8, a plasma arc generated by the plasma torch 8, and the plasma arc. A control device 26 for performing a stable supply control, a cooling water supply device 27 for cooling the electrode and the torch body,
And an air supply device 28 for supplying air to be a plasma forming gas.

For example, an electrode of AC400V is applied to the power supply device 4 described above. For the control device 26, the power is turned on and the following control items are set in advance.

When the plasma torch 8 is of a transfer type as shown in FIG. 2, the + pole is connected to the plasma torch 8 through the cable 17 from the power supply device 4, and the − pole is connected to the counter pole 10 through the cable 22 to generate the plasma. A voltage is applied between the torch 8 and the counter electrode 10. Further, at the time of starting the pilot arc generation, for example, the arc gas pressure is set to 18 PSIG and the arc gas flow rate is set to 7 SCFM.

Also, during operation to generate the main arc, for example, low pressure arc gas pressure is 20 PSIG, high pressure arc gas pressure is 35 PS
IG, moving gradient from start to low pressure arc gas pressure is 1 PSI
G / sec, low pressure setting time is 10 sec, moving gradient from low pressure arc gas pressure to high pressure arc gas pressure is 1 PSIG / sec, high pressure setting time is 10 sec, moving gradient from high pressure arc gas pressure to low pressure arc gas pressure is 1 PSIG / sec .

Alternatively, when the plasma torch 8 is of the non-transfer type as shown in FIG. 3, the counter electrode of the graphite electrode is not necessary, and the negative electrode is connected to the electrode built in the plasma torch 8 through the cable 18 and the pilot arc. At the time of start-up for generating, the arc gas pressure is set to 18 PSIG and the arc gas flow rate is set to 7 SCFM. Also, during the operation to generate the main arc, for example, low pressure arc gas pressure 20PSIG,
High pressure arc gas pressure is 40 PSIG, moving gradient from startup to low pressure arc gas pressure is 3 PSIG / sec, low pressure setting time is 10 se
c, the moving gradient from the low pressure arc gas pressure to the high pressure arc gas pressure is 1 PSIG / sec, the high pressure setting time is 10 sec, the moving gradient from the high pressure arc gas pressure to the low pressure arc gas pressure is 1 PSIG / sec.
Set to sec.

Furthermore, the cooling water pump 29 in the cooling water supply device 27 is operated to send the cooling water CW from the water tank 30 to the heat exchanger 33,
After heat exchange in the heat exchanger 33, the heat exchanger 33 supplies the plasma torch 8 through the manifold 34 and then the cooling water pipes 19 and 20, and the cooling water CW from the manifold 34 in the arrow direction. To the furnace lid 7 to cool the plasma torch 8 and the furnace lid 7. At this time, for example, set the torch cooling water flow rate to 20-40 GPM.
And set the torch cooling water pressure to 180-250 PSIG.

Further, the air compressor of the air supply device 28 is operated, and compressed air is supplied from the manifold 34 to the plasma forming air pipe 21.
Through the plasma torch 8. At this time, the arc gas pressure is, for example, 18 PSIG which is the above-mentioned setting condition, and the arc gas flow rate is 7 SCFM. The initial voltage (DC) for generating the main arc is set to about 700V.

Next, the vertical movement and tilting mechanism of the furnace body 6 in this plasma incineration ash melting apparatus will be described with reference to FIGS. 4, 5, 6, and 7.

The trolley 2 has wheels 35 and is configured to be able to travel on the rail 3. The trolley 2 is provided with a hydraulic jack 36 for vertically moving the trolley 2 itself in order to vertically move the furnace body 6 in the vertical movement and tilting mechanism. In addition, a support 37 and a support base 40 are provided on the carriage for supporting the furnace body 6. The lower end of the column 37 is fixed to the carriage 2, and the upper end is pivotally attached to a bracket provided on the furnace body 6.

Further, a hydraulic cylinder 39 having a piston rod 43 is provided between the furnace body 6 and the carriage 2 in order to tilt the furnace body 6 in the vertically moving and tilting mechanism with respect to the carriage 2. That is, one end of the hydraulic cylinder 39 is pivotally attached to the carriage 2 at a pivot 41, and the other end is pivotally attached to the furnace body 6 at a pivot 42.

The operation of the furnace body 6 provided with the vertical movement and tilting mechanism is achieved as follows. First, the truck 2 carrying the furnace body 6 travels on the rail 3 and is positioned under the furnace lid 7 installed in a fixed state, as shown in FIG. In this state, a gap L exists between the lower surface of the furnace lid 7 and the upper surface of the furnace body 6. Then, the hydraulic jack 36 is operated to raise the truck 2. As the carriage 2 rises, the furnace body 6 on the carriage 2 also rises, and as shown in FIG. 4, the lower surface of the furnace lid 7 and the upper surface of the furnace body 6 are brought into contact with each other to remove the slag discharged from the furnace body 6. Except for the outlet 25, a closed state is established, and the furnace body 6 is fixed to the furnace lid 7 there.
With the furnace body 6 attached to the furnace lid 7, the plasma torch 8 functions as described below, and the operation of melting the incineration ash B is performed.

After the incineration ash melting operation is completed, the operation opposite to the above is performed, the truck 2 is run on the rail 3, and as shown in FIG.
When the furnace body 6 is pulled out from the furnace lid 7, the molten slag is accumulated in the furnace body 6. Therefore, in order to discharge the molten slag from the furnace body 6, the furnace body 6 has a slag receiver for receiving the molten slag. Tilt in place. The tilting movement in the vertical movement / tilting mechanism of the furnace body 6 can be achieved by operating the hydraulic cylinder 39.

That is, the hydraulic cylinder 39 is operated, and as shown in FIG.
When the piston rod 43 of the hydraulic cylinder 39 is extended,
The furnace body 6 pivots with the upper end of the column 37 as a pivot point 38 and tilts with respect to the carriage 2. Due to the tilting of the furnace body 6, the molten slag accumulated in the furnace body 6 is discharged to a predetermined slag receiver.

In this plasma incineration ash melting device, the incineration ash generated from the incinerator or the incineration ash B collected from the dust collector is
Once collected in the ash container 31, the ash container 31
It is thrown into the ash hopper 12 from. The incinerated ash B charged into the ash hopper 12 is continuously or intermittently charged into the plasma arc furnace 5 through the chute 9 by the ash supply device 32.

The various conditions for discharging the plasma torch 8 are set as described above. Under these set conditions, the plasma torch 8 is
A high-energy pulse is applied between the electrode and the counter electrode 10 to generate a pilot arc. Then, after the main arc is generated, by setting a predetermined current (for example, 200-300A) and a predetermined voltage (for example, 400-500V),
The thermal energy of the plasma arc is applied to the incineration ash B which is the object to be heated. That is, a plasma arc is generated by the discharge of the plasma torch 8, and the incineration ash B containing oxides, highly molten substances, etc. becomes molten slag 13 in a molten state by the thermal energy of the plasma arc, and the metal is molten metal in the furnace. It continuously or intermittently flows out from the slag discharge port 25 of the body 6 and is taken out to the outside as the slag S to the slag yard 14.

Further, the combustion gas G generated by melting the incinerated ash B is guided by the exhaust gas outlet cover 24 and is sent to the exhaust gas treatment device 15 through the exhaust gas duct 23. The combustion gas G is processed by the exhaust gas processing device 15, and the cleaned exhaust gas EG is exhausted from the chimney or the like to the atmosphere by the induction fan 16. Further, the incinerated ash B collected by the exhaust gas treatment device 15 is re-input to the exhaust hopper 12, or the slag S is discharged.
Is treated as.

At this time, the current is PID controlled, and the voltage is determined by the distance between the counter electrodes and the variation cycle of the arc gas pressure in the case of the transfer type plasma torch 8. Further, in the case of the non-transfer type plasma torch, it is determined only by the fluctuation cycle of the arc gas pressure. Further, when a non-transfer type plasma torch is used, a plasma arc is generated between the positive electrode and the negative electrode built in the plasma torch, and the incinerator ash B is melted by the arc heat, that is, plasma energy.

〔The invention's effect〕

The plasma incineration ash melting apparatus according to the present invention is configured as described above and has the following effects. That is, this plasma incineration ash melting apparatus is a furnace lid fixedly provided with an incinerator ash supply port and an exhaust gas outlet, a plasma torch provided in the furnace lid, and is movable up and down with respect to the furnace lid and Since it is composed of a furnace body made of refractory material having a slag discharge port that can be attached to the furnace lid, and a trolley in which the furnace body is tiltably installed, it is possible to continuously and stably obtain a plasma arc by the plasma torch. For example, even if incinerator ash containing a highly molten substance such as metal or pottery is directly put into a melting furnace, the thermal energy of high-temperature plasma is applied to the incinerator ash by radiation or conduction and the incinerated ash is melted. You can

In particular, since the carriage is provided with a vertically moving and tilting mechanism, at the end of the melting work of the incineration ash, the furnace body is lowered from the furnace lid, and the carriage moves the furnace body out of the furnace lid. Then, the furnace body is tilted at a predetermined place, and the residual molten slag can be easily and surely discharged to the outside of the furnace body in the furnace body.

Furthermore, ignition or extinguishing of the plasma torch can be instantaneously operated, and operation and maintenance can be easily performed.
Since the molten slag in the furnace body is continuously discharged outside the furnace by overflow from the tap hole, the incinerated ash can be sequentially or continuously charged into the melting furnace, and the incinerated ash can be continuously melted. it can.

Furthermore, the amount of air required as the plasma forming gas is small, the amount of exhaust gas is small, and the melting furnace itself can be made compact. Moreover, since the plasma torch is used, the heating area is limited, and the temperature rise of the entire furnace is small,
Heat loss from the furnace surface is reduced.

Further, when the incineration ash is melted, the heavy metal contained in the incineration ash is usually in the form of highly volatile chloride,
When air is used as the plasma-forming gas, it strongly oxidizes with the air and changes into a low-volatile oxide by the oxidative action, so most of the heavy metals are melted and fixed in the molten slag and volatilized in the exhaust gas. It does not elute and does not elute from the slag produced. In addition, since the power fluctuation hardly occurs, the influence on the power source is small.

Further, since the plasma torch is attached so as to be able to move up and down and tilt with respect to the furnace lid, it is possible to ignite a plasma arc by bringing the plasma torch close to the counter electrode.
Depending on the temperature situation of the furnace body due to the influence of molten slag,
The distance can be adjusted so as to separate the plasma torch from the furnace body, and when the plasma torch is extinguished to separate the furnace body from the furnace lid, the plasma torch is raised to smoothly move the furnace body. It can be carried out.

Furthermore, since the exhaust gas outlet hood is provided at the slag discharge port, the slag is prevented from being cooled and solidified,
The exhaust gas is smoothly discharged from the exhaust gas outlet in the upper part of the furnace body through the induction fan through the exhaust gas outlet hood.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a plasma incineration ash melting apparatus according to the present invention, and FIG. 2 is an explanatory view explaining a transfer type plasma torch used in the incinerator ash melting apparatus of FIG. 1,
FIG. 3 is an explanatory view for explaining a non-transfer type plasma torch used in the incinerator ash melting apparatus of FIG. 1, and FIG. 4 is a mounting state of a furnace body and a furnace lid in the plasma incinerator ash melting apparatus of the present invention. Fig. 5 is an explanatory view showing a state in which the furnace body and the furnace lid are removed, Fig. 6 is an explanatory view showing a truck carrying the furnace body, and Fig. 7 is a diagram showing the furnace body with respect to the truck. It is an explanatory view showing a tilted state. 1 ... Plasma system, 2 ... Bogie, 3 ... Rail,
5 ... Plasma arc furnace, 6 ... Furnace body, 7 ... Furnace lid, 8
...... Plasma torch, 10 …… counter electrode, 11 …… torch lifting device, 12 …… ash hopper, 13 …… molten slag, 15 …… exhaust gas treatment device, 24 …… exhaust gas outlet cover, 25 …… slag discharge port , 36 …… hydraulic jack, 39 …… hydraulic cylinder.

Front Page Continuation (72) Inventor Toshiro Amamiya 1-27 Konan, Minato-ku, Tokyo Ebara Infilco Co., Ltd. (72) Inventor Akira Miyamura 4-2-1 Honfujisawa, Fujisawa-shi, Kanagawa EBARA Research Institute (56) Reference JP-A-59-142374 (JP, A) JP-A-64-6611 (JP, A) Practical application Sho-60-86731 (JP, U) JP-B-59-16199 (JP) , B2)

Claims (3)

[Claims] 1. A furnace lid fixedly provided with an incinerator ash supply port and an exhaust gas outlet, a plasma torch provided on the furnace lid so as to be vertically movable and tiltable with respect to the furnace lid, and the furnace lid. A furnace body made of a refractory material that is attachable / detachable and provided with a slag discharge port, a truck carrying the furnace body that moves the furnace body with respect to the furnace lid, and the furnace body on the furnace lid. Vertical movement provided on the carriage capable of moving the furnace body up and down with respect to the furnace lid so as to be attachable / detachable and tilting the furnace body for discharging residual molten slag in the furnace body A plasma incineration ash melting apparatus comprising: a tilting mechanism and an exhaust gas outlet hood provided at the slag discharge port. 2. The plasma incineration ash melting apparatus according to claim 1, wherein a counter electrode of the plasma torch is provided on a furnace bottom portion of the furnace body. 3. The vertical movement and tilting mechanism is mounted between a hydraulic jack mounted on the carriage for raising the furnace body, and between the furnace body and the carriage for tilting the furnace body. 2. The plasma incinerator ash melting apparatus according to claim 1, wherein the plasma incineration ash melting apparatus comprises a hydraulic cylinder.