JPH11201431A - Direct fusion furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely seal a direct fusion furnace from outside and raise operation stability, by comprising a piston pump or plunger pump as a pneumatic pump for pneumatically feeding wastes directly in the direct fusion furnace from a waste hopper for housing wastes through a piping. SOLUTION: As waste feed means 30, a waste hopper 32 for housing wastes, a piston pump 34 for pneumatically feeding the wastes directly in a melting furnace 10 from the waste hopper 32, and a piping 36 from the piston pump 34 directly to a charge port 22 of the melting furnace 10, are provided. Using the piston pump 34 or plunger pump, the waste is pneumatically fed through the piping 36 to form a high-packing density waste packed bed in the piping 36, thereby sealing a combustion gas in a direct fusion furnace operative at a positive pressure from the air. Between the pneumatic feed pump 34 and the waste hopper 32, a water seal tank 42 is provided for a water sealing between the pneumatic feed pump 34 and waste hopper 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct melting furnace for waste, and more particularly, to a means for sealing (blocking) the direct melting furnace from the atmosphere and stably supplying waste to the direct melting furnace. The present invention relates to a direct melting furnace provided with:

[0002]

2. Description of the Related Art General waste such as municipal waste is increasing more and more due to artificial concentration in cities, and is discharged from factories as economic activities progress and urban redevelopment progresses. Industrial waste such as industrial waste and construction waste discharged from the demolition site of buildings are becoming increasingly diverse and diverse.
And the amount is also increasing significantly. Conventionally, waste such as general waste and industrial waste has been landfilled in landfills or incinerated in ordinary garbage incinerators. Due to pollution and the like, opposition to landfill disposal has become severe, and landfill sites themselves are becoming less suitable. Therefore, it is actually difficult to landfill waste. In addition, the incineration of waste in a normal garbage incinerator involves the danger of release of harmful substances such as dioxins.
In addition, since secondary treatment of incinerated ash containing heavy metals and the like is required, incineration of wastes tends to be regulated.

[0003] In recent years, attention has been paid to a method of melting waste using a direct melting furnace. A direct melting furnace is a type of incinerator that burns waste and converts the remaining incineration ash into molten slag at once in one incinerator without taking it out of the furnace. The waste gas is converted into a gas containing decomposition gas and molten slag. Harmful components such as heavy metals contained in the waste are fixed as molten slag, so that the heavy metals do not elute and there is very little risk of secondary environmental pollution. Also,
The gas generated by the incineration process in the direct melting furnace contains few harmful gas components such as dioxin, and even if there is a little, it burns at a high temperature in the gas combustion furnace attached to the melting furnace. Is discharged as

Here, a configuration of a conventional direct melting furnace will be described with reference to FIG. FIG. 4 is a schematic diagram showing a configuration of a conventional direct melting furnace. As shown in FIG. 4, the conventional direct melting furnace 10 is configured as a shaft furnace having a vertical furnace body lined with a refractory material. It has a gas combustion furnace 11 for burning gas containing gas. The inside of the direct melting furnace 10 is divided into a drying zone 12, a pyrolysis zone 14, and a combustion / melting zone 16 from the top.
Is usually located in the large diameter part in the center of the furnace body,
6 is located in the reduced diameter portion below the large diameter portion. Further, the direct melting furnace 10 has a slag outlet 1 for extracting molten slag.
8 into the lower part of the combustion / melting zone 16, that is, the bottom of the furnace body, an oxygen inlet 20 for blowing oxygen for combustion into the combustion / melting zone 16 above the slag outlet 18, and waste to be treated is put into the furnace. And a gas outlet 2 through which cracked gas flows out.
4 is provided above the inlet 22. Direct melting furnace 10
Is a gas outlet 24 and a duct 2 connected to the gas outlet 24.
6 and connected to the gas combustion furnace 11 to supply the cracked gas to the gas combustion furnace 11.

[0005] Hereinafter, with reference to FIG. 5, a method of treating waste by a conventional direct melting furnace will be described. FIG. 5 is a schematic diagram for explaining the state of treatment of waste in a direct melting furnace. In the treatment of the waste, as shown in FIG. 5, while blowing oxygen from the oxygen inlet 20 at a flow rate equal to or less than the theoretical amount of oxygen required for complete combustion of the waste, the waste is introduced into the furnace from the inlet 22. throw into. The input waste is
First, in the drying zone 12, a pyrolysis zone 14 below the drying zone 12 is used.
And is dried by the ascending decomposition gas, and then descends to the pyrolysis zone 14 where it is thermally decomposed by the high temperature atmosphere to generate a decomposition gas. Subsequently, the waste descends into a combustion and melting zone 16 below the pyrolysis zone 14 which is maintained at a temperature of 1600 ° C. or higher, where it burns and melts, and finally, with molten slag. And flows out of the slag outlet 18. The cracked gas generated in the pyrolysis zone 14 is combustible and flows out of the gas outlet 24 together with the combustion gas generated by the combustion of the waste.

The gas generated in the direct melting furnace 10 is flammable and has a high temperature and heat energy. Therefore, the gas is combusted in an attached gas combustion furnace 11 or the like to recover the heat energy. Thermal energy is recovered, for example, as steam and is used for power generation and the like.

[0007]

As described below, in the conventional direct melting furnace, when the waste is directly supplied to the melting furnace, the furnace is operated by setting the furnace pressure to a higher positive pressure than that outside the furnace. Therefore, there is a problem that it is difficult to directly seal the melting furnace from outside the furnace. In general incinerators such as stoker furnaces, the inside of the furnace is operated at a negative pressure in order to prevent the combustion gas that may contain harmful substances from leaking out of the furnace. Allows some air ingress. In such a general incinerator, the inside of the incinerator can be shut off from the outside of the incinerator by gas sealing the incinerator with a waste deposit layer formed at a waste inlet of the incinerator. However, furnaces that directly decompose waste and generate flammable gas, such as direct melting furnaces,
If the inside of the furnace is set at a negative pressure, air enters from outside the furnace, and an unexpected combustion reaction occurs, which is dangerous. Therefore, in the direct melting furnace, since the furnace pressure is set to a higher positive pressure than the outside of the furnace, it is operated at the conventional waste inlet to prevent the leakage of combustion gas containing decomposition gas to the outside of the furnace. The gas seal using only the waste deposit layer is not enough to directly shut off the inside of the melting furnace from outside the furnace, and another sealing mechanism is required.

Conventional pushers, vibratory feeders, conveyors and the like do not have a sealing mechanism for directly shutting off the melting furnace from outside the furnace. Requires a mechanism.
In addition, as a sealing mechanism of the waste supply means, it has been attempted to apply a conventional double damper, a rotary feeder, or the like, but they have a complicated structure and a large number of movable parts such as a rotating shaft. Failure to occur is likely to occur due to contact with waste, and operation control becomes complicated because a purge gas or the like is required. Failure or shutdown of the supply means that directly supplies waste to the melting furnace directly leads to shutdown of the entire equipment of the direct melting furnace, so that the waste supply means must have high operational stability. Has been requested.

It is an object of the present invention to provide a direct melting furnace which reliably seals the direct melting furnace from the outside of the furnace and has means for supplying waste with high operational stability.

[0010]

In order to achieve the above object, a direct melting furnace (hereinafter referred to as a first invention) according to the present invention comprises, from the top, a drying zone, a pyrolysis zone, and a combustion / melting zone. It is configured as a vertical shaft furnace divided into a furnace, and the waste that is put into the furnace and forms a waste layer is dried, thermally decomposed, burned and melted in each area, and contains the decomposition gas of the waste. In a direct melting furnace for converting gas and molten slag, a waste hopper containing waste, and a piston pump or a plunger pump as a pressure pump for directly feeding waste into the melting furnace via a pipe from the waste hopper through a pipe. It is characterized by having.

According to the present invention, waste is pressure-fed by a piston pump or a plunger pump from a waste hopper via a pipe directly to a waste layer of a melting furnace, and a high-density waste filling is performed in the pipe. By forming a layer, it is possible to seal a combustion gas including a decomposition gas in a direct melting furnace operated at a positive pressure. The shortest length of the waste packed bed required for sealing, that is, the shortest pipe length depends on the level of the pressure in the furnace of the direct melting furnace, that is, the magnitude of the differential pressure between the furnace pressure and the atmospheric pressure. The power of the pump required to pump the waste through the pipe of the pipe length is the minimum power required for the seal.

Preferably, the intermediate tank is formed as an intermediate tank for temporarily storing the waste falling from the waste hopper, disposed above the pressure pump, connected to the suction port of the pressure pump, and immersed in the water. A water-sealing tank for water-sealing between the waste hopper and the pressure pump, and a position where the pipe between the pressure pump and the direct melting furnace is at least partly higher than the discharge port of the pressure pump by a predetermined height. To extend. The predetermined height is equal to the required water column height required for water sealing, that is, the differential pressure between the furnace pressure and the atmospheric pressure + α. For example, when a water column of 1 m is required, the predetermined height is 1 m. The water for water sealing may be stored in the water sealing tank with the water accompanying the waste, and when water alone is insufficient for water sealing,
Water may be separately injected. When the water for water sealing is excessive, for example, the water is overflowed from the water sealing tank. As a result, the water seal tank, the pressure pump and the discharge pipe are completely sealed by the water seal, so that the combustion gas in the direct melting furnace operated at a positive pressure can be reliably sealed from the outside of the furnace. Compared to the case where the inside is sealed with a waste filling layer,
It can be sealed with a short pipe length. Also, when the water in the water seal tank is pumped through the piping together with the waste by the pressure pump, a thin water film is formed between the waste and the piping wall to reduce the frictional resistance between the waste and the piping wall. Thus, the required power of the pump can be reduced.

Also, instead of extending the pipe at a position higher than the discharge port of the pressure pump by a predetermined height in at least a part of the path, as an alternative to water sealing, the pump shaft of the pressure pump is moved from the drive side to the discharge side. The pump is installed so as to incline obliquely upward toward, and a predetermined length of the discharge port side connection pipe of the pump is laid obliquely upward along the extension direction of the pump shaft of the pump. Is also good. The predetermined length is a length at which the tip of the discharge port side connection pipe becomes higher by the above-described predetermined height. In this water-sealing mode, compared to the above-mentioned water-sealing mode, there is no need to provide a pipe rising section in the pump discharge pipe, and waste can be directly pumped to the melting furnace with only a straight pipe. There is no danger of waste accumulating and clogging in the part. In this aspect, the discharge port may be directed upward and only the cylinder axis of the pump may be inclined.

Further, another direct melting furnace (hereinafter referred to as a second invention) according to the present invention is a vertical shaft furnace divided into a drying zone, a pyrolysis zone, and a combustion / melting zone from the top. Direct melting where the waste that is composed and put into the furnace and forms a waste layer is dried, thermally decomposed, burned and melted in each area, and converted into a gas containing cracked gas from the waste and molten slag The furnace is equipped with a waste hopper for containing waste, and a multi-screw screw type dust feeder that feeds waste directly from the waste hopper through a pipe into the melting furnace. And a sealing means for sealing a pipe between them.

More preferably, a waste crusher is provided below the waste hopper, and the waste to be supplied to the pressure pump is crushed in advance, so that the size and shape of the waste are uniformed and the pumping capacity is improved. This makes it more difficult for waste to be caught and clogged in the piping. Further, by making the size and shape of the waste uniform, the waste packed bed becomes more dense, and the combustion gas of the direct melting furnace can be more reliably sealed. Furthermore, since the pipe length required for sealing between the pressure pump and the direct melting furnace can be shortened,
The discharge pressure of the pressure pump can be reduced. In a conventional direct melting furnace, a crusher for crushing waste and a conveyor such as a conveyor for transporting the crushed waste are installed at separate locations, and a crush waste pit is provided between the crusher and the transport means. Is provided. However, in this aspect, the crusher is provided on the pressure pump and the crush waste is dropped directly from the crusher to the pressure pump, thereby eliminating the necessity of installing a crush waste pit requiring a large space. .

[0016]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiment 1 This embodiment is an example of an embodiment of a direct melting furnace according to the first invention, and FIG. 1 is a schematic diagram showing a configuration of a direct melting furnace of this embodiment. Direct melting furnace 10 of this embodiment
In addition to the configuration of the conventional direct melting furnace 10 shown in FIG. 4, a waste hopper 32 for storing waste and a waste hopper 32 as shown in FIG.
And a pipe 36 from the piston pump 34 to the inlet 22 of the melting furnace 10 directly. As the piston pump, for example, a putzmeister pump manufactured by Putzmeister sold by Lhasa Trading Co., Ltd. can be used. In the direct melting furnace 10 of the present embodiment, the waste hopper 32
The waste is directly pumped by a piston pump 34 onto the waste layer of the melting furnace 10 through a pipe 36 through a pipe 36 to form a waste-packed layer having a high packing density in the pipe 36, so that the positive pressure The combustion gas containing the decomposed gas in the direct melting furnace 10 operated in the above can be sealed from outside the furnace. Further, in the present embodiment, the input nozzle 3 formed of a member having a semicircular cross section in a form in which the upper half of the pipe is removed.
Numeral 8 extends directly from the inlet 22 to the center of the melting furnace 10, so that the waste can be uniformly dispersed and supplied on the waste layer. Further, the injection nozzle 38 may be water-cooled to prevent heat-induced wear.

Embodiment 2 This embodiment is another example of the embodiment of the direct melting furnace according to the first invention, and FIG. 2 is a schematic diagram showing the configuration of the direct melting furnace of this embodiment. It is. As shown in FIG. 2, the direct melting furnace 10 of the present embodiment has a structure in which a waste hopper 32 and a piston pump 34 A rising portion 46 having a crusher 40 for crushing waste from above and a water sealing tank 42 and bending with a large radius of curvature is provided as a part of a pipe 36 at a portion of a discharge port connection pipe 44 of a piston pump 34. is there. The height H of the rising portion 46 is equal to the required water column height for water sealing, that is, the differential pressure between the furnace pressure and the atmospheric pressure + α. H is 1 m.

The crusher 40 is a crusher of a known structure directly connected to the waste hopper 32. For example, a roll-type crusher is used. The water sealing tank 42 is a hopper-shaped tank directly connected to the outlet of the crushed waste of the crusher 40, and has an overflow port 48 at the same position as the highest position of the rising portion 46.
It is a tank provided with. The crushed waste descends from the crusher 40 together with the accompanying water into the water sealing tank 42, a part of the accompanying water is pumped together with the crushing waste by the piston pump 34, and the remaining accompanying water stays in the water sealing tank 42. And piston pump 3
4 and the crusher 40, that is, between the melting furnace 10 and the atmosphere. Water entrainment tank 42 along with crushed waste
As the water level rises as it enters, the overflow port 48
, The water level of the water seal tank 42 is always at the position of the overflow port 48.

In this embodiment, since the water seal tank 42, the piston pump 34, and the discharge pipes 44 and 46 are completely sealed by the water seal, the combustion gas in the direct melting furnace 10 operated at a positive pressure can be reliably obtained. Can be sealed.

Embodiment 3 This embodiment is a modification of Embodiment 2 of the water ring type, and FIG. 3 is a schematic view showing the configuration of a direct melting furnace of this embodiment. The direct melting furnace 10 of the present embodiment is different from the direct melting furnace 10 of the second embodiment in that the piston pump 3
Instead of providing the rising portion 46 in the discharge port connection pipe 44 of No. 4, the piston pump 34 is installed so that the pump shaft of the piston pump 34 is inclined obliquely upward from the drive side to the discharge side, and the discharge port connection is performed. Without providing a rising portion 46 in the pipe 44, a pipe 36 is laid directly in a straight line up to the charging port 22 of the melting furnace 10 so that the charging port 22 and the overflow port 48 of the water sealing tank 42 are at the same position. I have.

In the present embodiment, the pipe 36 is straight, and does not have the pipe rising section 46 provided in the second embodiment. Therefore, waste is accumulated in the pipe 36 to block the pipe 36. There is no such danger, and the combustion gas in the direct melting furnace 10 operated at a positive pressure can be reliably sealed as in the second embodiment.

Embodiment 4 This embodiment is an embodiment of the second invention, and FIG. 6 is a schematic diagram showing a configuration of a direct melting furnace of this embodiment. The direct melting furnace 10 of this embodiment includes a multi-screw screw type dust feeder 50 as a waste supply means 31 for directly feeding waste into the melting furnace 10 from a waste hopper 32 via a pipe 36, The pipe 36 between the dust generator 50 and the direct melting furnace 10 is provided with a downwardly bent portion 52. The bent portion 52 functions as a water sealing type sealing means.

[0023]

According to the present invention, waste is pumped through a pipe using a piston pump or a plunger pump to form a waste-packed layer having a high packing density in the pipe, so that a positive pressure can be obtained. The combustion gases in the operated direct melting furnace can be sealed from the atmosphere. In addition, by providing a water seal tank between the pressure pump and the waste hopper and sealing the water between the pressure pump and the waste hopper, the combustion gas in the direct melting furnace operated at a positive pressure is removed from the atmosphere. Sealing can be performed more reliably.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a direct melting furnace according to a first embodiment.

FIG. 2 is a schematic diagram illustrating a configuration of a direct melting furnace according to a second embodiment.

FIG. 3 is a schematic view illustrating a configuration of a direct melting furnace according to a third embodiment.

FIG. 4 is a schematic diagram showing a configuration of a conventional direct melting furnace.

FIG. 5 is a schematic diagram illustrating the state of treatment of waste in a direct melting furnace.

FIG. 6 is a schematic diagram illustrating a configuration of a direct melting furnace according to a fourth embodiment.

[Explanation of symbols]

 10 Conventional Direct Melting Furnace 11 Gas Combustion Furnace 12 Drying Area 14 Pyrolysis Area 16 Combustion / Melting Area 18 Slag Outlet 20 Oxygen Inlet 22 Inlet 24 Gas Outlet 30 Waste Supply Means 32 Waste Hopper 34 Piston Pump 36 Piping 38 Input nozzle 40 Crusher 42 Water seal tank 44 Discharge port connection pipe 46 Rising section 48 Overflow port 50 Multi-screw screw type dust feeder 52 Bent section

Claims (5)

[Claims] 1. A drying zone, a thermal decomposition zone, and a combustion zone from the top.
It is configured as a vertical shaft furnace divided into a melting zone,
In a direct melting furnace in which the waste that is put into the furnace and forms a waste layer is dried, thermally decomposed, burned and melted in each area, and converted into a gas containing cracked gas of the waste and molten slag, A direct melting furnace comprising: a waste hopper for storing waste; and a piston pump or a plunger pump as a pressure pump for directly pumping the waste into the melting furnace from the waste hopper via a pipe. 2. An intermediate tank formed to temporarily store waste falling from a waste hopper, disposed above the pressure pump, connected to a suction port of the pressure pump, and immersed in the water. A water-sealing tank for water-sealing between the waste hopper and the pressure pump, and a pipe extending between the pressure pump and the direct melting furnace at a position higher than the discharge port of the pressure pump by a predetermined height in at least a part of the route. The direct melting furnace according to claim 1, wherein: 3. An intermediate tank formed as an intermediate tank for temporarily storing waste falling from a waste hopper, disposed above the pressure pump, connected to a suction port of the pressure pump, and immersing the waste in water. A water-sealing tank for water-sealing between the waste hopper and the pump is provided.The pump is installed so that the pump shaft of the pump is inclined obliquely upward from the driving side to the discharge side. 2. The direct melting furnace according to claim 1, wherein the pipe is laid so that a predetermined length of the outlet side connection pipe is directed obliquely upward along the extension direction of the pump shaft of the pressure pump. 4. A drying zone, a pyrolysis zone, and a combustion zone from the top.
It is configured as a vertical shaft furnace divided into a melting zone,
In a direct melting furnace in which the waste that is put into the furnace and forms a waste layer is dried, thermally decomposed, burned and melted in each area, and converted into a gas containing cracked gas of the waste and molten slag, It has a waste hopper for storing waste, and a multi-screw screw type dust feeder that feeds waste directly from the waste hopper through piping to the melting furnace, and a space between the dust feeder and the direct melting furnace. A direct melting furnace comprising a sealing means for sealing a pipe. 5. The direct melting furnace according to claim 1, further comprising a waste crusher below the waste hopper.