JPH05288330A - Method for cooling molten materials extracted from waste material melting furnace - Google Patents

Abstract

PURPOSE:To enable slug-like molten material extracted from a waste material melting furnace to be uniformly and gradually cooled by a method wherein a moving immersed temperature keeping with particles heated is formed at a transporting surface and the extracted molten material is supplied to the surface. CONSTITUTION:Particles R heated by an injected furnace gas G at a lower part of a powder charging part 5 is divided by a heating fin 11, and further supplied onto the transporting surface of an apron conveyor 6. Molten material M flowed down from a hot melt spout 3 is flowed down onto the downstream bed 15 formed by the particles R so as to form a gradual cooling layer 19. A cover 17 with the particles R is formed on the gradual cooling layer 19. The molten material M is transported with the apron conveyor 6 while its temperature being kept well. The molten material M gradually cooled with a discharging part 20 is discharged together with the particles R forming the temperature keeping layer. With such an arrangement, the gradual cooling of the molten slag can be accomplished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to municipal solid waste, various industrial wastes, or intermediate products obtained by drying, incineration, crushing, etc., using a lumpy carbonaceous combustible substance such as coke as a heat source. The present invention relates to treatment of a melt in a waste melting furnace, which is heated and melted to be recovered as a civil engineering material, a concrete fine aggregate, and a slag material for a surface makeup aggregate.

[0002]

2. Description of the Related Art Conventionally, a lumpy carbonaceous combustible substance such as coke is charged together with the residue of a waste incinerator, and combustion air is blown from the tuyere to burn the coke to obtain a high-temperature gas. There is a melting furnace that heats and melts the residue of the waste incinerator to extract it as a slag-like melt. In such a melting furnace, the extracted melt is usually water-cooled in order to simplify the treatment.

However, when the melt is water-cooled, the melt is rapidly cooled to form a granular glassy material, which has low strength and is insufficient for reuse as an aggregate or the like. Therefore, in recent years, a method of gradually cooling the extracted melt to make it crystalline has been attempted.

As a method of crystallizing the extracted melt, Japanese Patent Laid-Open No. 58-60114 discloses a method in which quick lime, slaked lime, calcium oxide and the like are added to a treated waste to determine the basicity of ash in the treated material. It is disclosed that the melting rate is increased to increase the cooling rate of the melt to obtain a crystalline material having high strength. Further, Japanese Patent Application Laid-Open No. 58-49825 discloses a method of preventing a vitrification by receiving a molten processed product in a container, placing the container in a cooling chamber for supplying a high temperature gas from a melting furnace, and gradually cooling the container. ing. Further, Japanese Patent Application Laid-Open No. 58-60118 discloses that an exothermic flux is mixed with a melt and gradually cooled.

In all of these methods, the crystallization is promoted by gradually cooling the melt, but since the surface of the molten slag mass comes into contact with the receiver and the like, the cooling rate is partially high. It is unavoidable that some parts are difficult to crystallize.
Therefore, the obtained crystallized slag has a problem that the crystallized state varies.

Further, in Japanese Patent Publication No. 62-1344, an apron conveyor having a refractory material lined on the conveying surface is arranged, and recycled soil is supplied from the side better than the outlet of the conveyor to convey the conveyor. It is disclosed that a bed of reclaimed earth and sand is formed on the transport surface and the molten slag of waste is gradually cooled and solidified by the reclaimed earth and sand. However, the cooling rate of the molten slag is high on the top and side surfaces of the reclaimed earth and sand, and the whole cannot be made into a uniform crystal body.
This problem becomes particularly noticeable when the amount of molten slag is small.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to establish an efficient means for uniformly cooling the slag-like melt extracted from the waste melting furnace.

[0008]

According to the present invention, a granular material is heated by a gas ejected from a tap hole, the heated granular material is supplied to a conveying surface, and the moving surface is kept warm by the heated granular material. It is characterized in that a layer is formed, the extraction melt is supplied to the surface of the moving heat insulation layer, and the extraction melt is surrounded by particles and gradually cooled.

The moving heat-retaining layer made of granular material is obtained in the crushing and sizing step which is a post-process of the extraction melt and is obtained from 2-1.
Granules with a diameter of 0 mm are suitable because of their low thermal conductivity.

By passing the jetted gas through the granular material layer in a counter flow, a heat exchange state with less pressure loss can be obtained.

The granular material that has undergone heat exchange by the gas discharged from the tap hole is supplied in a uniform thickness so as to surround the tap molten material.

The preheating temperature of the granular material is controlled with the upper limit being a temperature at which the slag does not sinter or soften, so that a stable transport state can be obtained without fixing the moving layer and the heat retaining effect is enhanced.
Further, air is blown to the main stream of the jetted combustible gas at the tip of the tap hole to secondarily burn the jetted gas. Combustion temperature is NOx
Combustion control is performed at 800-900 ° C in consideration of the generation of gas, but the temperature of the discharged gas after heat exchange with the particulate matter is low,
It is replaced as a part of the secondary air for dilution in the secondary combustion furnace on the downstream side of the melting furnace.

[0013]

The present invention is intended to effectively utilize the high temperature in-furnace gas ejected together with the melt from the tap hole, for extracting the sensible heat or latent heat of the in-furnace gas ejected from the tap hole to gradually cool the melt. It is effectively used to maintain the heat retention state of.

Further, by forming a heat insulating and heat-retaining layer of granular material so as to surround the melt, uniform and slow cooling of the continuously extracted melt is achieved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an example of an apparatus for carrying out the present invention.

In FIG. 1, reference numeral 1 denotes a melting furnace having a blower tuyere 2 and a tap hole 3 below, and a charging waste residue A is heated and melted by a high-temperature gas generated in a high-temperature hearth 4 and melted. Is continuously extracted little by little from the tap hole 3, and a furnace gas G of about 1400 ° C. is jetted from the upper opening of the tap port 3, and the jet gas G is burned by the combustion air, After passing through the granular material filling section 5 arranged continuously in No. 3, the sensible heat and latent heat exchange heat with the granular material in the granular material filling section 5 to heat the granular material R to 750 to 850 ° C. The particles are discharged from above the granular material filling section 5. The heated granular material R forms a moving heat-retaining layer 7 on the apron conveyor 6 arranged at the lower position, and the melt is allowed to flow down on the moving heat-retaining layer 7 to be gradually cooled.

FIG. 2 is a view of FIG. 1 taken along the line AA, in which a granular material supply device 8, a heating section in the granular material filling section 5, and a moving heat insulation layer 7 on the apron conveyor 6 are formed. Indicates the state.

The granular material R is crushed by cooling the melt,
Granules from the melt obtained after sizing are supplied from the storage hopper 9 to the top of the granule filling section 5 by the screw feeder 10. 11 is a heating space 12 formed above the tap hole 3 located below the granular material filling section 5
Which is a heating fin formed around the heating tap, the furnace gas G ejected from the upper side of the tap hole 3 once stays in the heating space 12 to heat the heating fin 11 and then from the gap between the fins. Heat is exchanged between the granular materials R, and is discharged from the top discharge port 13 to the secondary combustion furnace through the adjusting valve 14.

Below the granular material filling section 5, the granular material R heated to 750 to 850 ° C. by the gas G in the ejection furnace.
Is bifurcated by the heating fins 11 to be supplied on the conveying surface of the apron conveyor 6 whose speed is variable and which has a concave accommodating portion formed on the surface. An adjusting plate 16 for forming a falling bed 15 of the melted material M by the granular material R is provided at the rear part of the apron conveyor 6 in the conveying direction. An adjusting plate 18 for forming the cover 17 of the granular material R is formed in the conveying direction of the apron conveyor 6.

The melt M flowing down from the tap hole 3 flows down on the flow-down bed 15 formed by the granular material R to form the slow cooling layer 19, and the granular material R is further formed on the slow cooling layer 19. The cover 17 is formed, and the melt M is conveyed on the apron conveyor 6 while being kept warm, and the melt M slowly cooled in the discharging section 20 is discharged together with the granular material R forming the heat retaining layer. It

The time required for slow cooling is determined by the conveyor speed and the conveyor length. The slowly cooled slag may be sent to the crusher together with the granular slag from the end of the conveyor, and is sized to an optimum aggregate size through a sieve.

FIG. 3 shows the state of the melt M in the moving heat insulating layer 7 conveyed on the apron conveyor 6,
The periphery thereof is conveyed while being completely surrounded by the falling bed 15 and the cover 17 made of the preheated granular material, and is gradually cooled to form the melt gradually cooling layer 19.

As a result, the melt M extracted from the tap hole 3 is heated by the jet gas G in a heat-retaining state, is gradually annealed, and can be reused in various directions as crystalline slag.

[0024]

The present invention has the following effects.

(1) The optimum crystallization conditions can be selected according to the tapping capacity, the slow cooling of the molten slag can be achieved, and the selection use of the extracted melt is widened.

(2) The heat of the gas ejected from the tap hole can be used, and the thermal efficiency of the entire process is improved.

(3) In the case of waste containing metal, the metal solidifies into a rod shape at the bottom of the molten slag, and it is easy to divide and separate at the time of crushing, which facilitates metal recovery.

(4) As the slow cooling bed, the particulate matter generated in the system can be used, the utilization circulation system is established, and the utilization efficiency of the device is improved.

[Brief description of drawings]

FIG. 1 shows an example of a device for implementing the present invention.

FIG. 2 is a view of FIG. 1 seen from the line AA.

FIG. 3 shows a state of a melt that is conveyed while being surrounded by a moving heat retaining layer.

[Explanation of symbols]

A Charging waste combustion residue M Extraction melt G In-furnace gas 1 Melting furnace 2 Blower tuyere 3 Outlet port 4 High-temperature hearth 5 Granule filling part 6 Apron conveyor 7 Moving heat insulation layer 8 Granules supply device 9 Storage Hopper 10 Screw feeder 11 Heating fin 12 Heating space 13 Top discharge port 14 Adjusting valve 15 Downflow bed 16 Downflow bed forming adjusting plate 17 Granular cover 18 Adjusting plate for forming granules 19 Melt slow cooling layer 20 Discharge part

Claims (2)

[Claims] 1. A particulate matter is heated by a gas blown from a tap, a heated particulate matter is supplied to a conveying surface to form a moving heat retaining layer by the particulate matter on the conveying surface, and the moving insulating layer is extracted on the surface. A method for cooling a melt extracted from a waste melting furnace, in which a melt is supplied, and the extraction melt is surrounded by particles and gradually cooled. 2. The method for cooling a melt extracted from a waste melting furnace according to claim 1, wherein the granules are particles obtained by cooling the melt extracted from the waste melting furnace.