JP4674663B2 - Furnace structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a furnace structure used when melting an object to be processed such as waste.
[0002]
[Prior art]
The present inventor has already proposed a treatment method and apparatus intended for the melting treatment of general waste, medical waste, and nuclear waste. Here, the plasma torch is used as the heat source inside the furnace body, and the thermal decomposition in a partially reducing atmosphere causes the gaseous object containing combustible fine particles (which is burned in the next stage) and pyrolysis from the object to be treated. Alternatively, a combustion residue is generated, and the pyrolysis or combustion residue is melted at the bottom of the furnace to obtain a reusable molten slag containing no unmelted material.
[0003]
The problem here is that the furnace structure used in the melt processing apparatus needs to withstand an internal temperature of about 1700 ° C. In general, the outer wall of the furnace body has a statutory standard of maintaining a safe temperature of 70 ° C. or lower in the state of use of the furnace, and in the manufacture of the furnace body, the structure of the furnace wall that can clear this value is a design condition.
[0004]
However, as proposed by the present inventor, when the inside of the furnace is heated using a plasma torch or the like, according to many experimental results, the first refractory layer (for example, refractory brick) exposed on the inner wall surface is exposed. The surface of the steel gradually melts down in the course of use, and the temperature gradient from the inner wall surface to the outer wall surface of the third layer (heat insulating material) via the second layer (heat transfer material such as cement) It was confirmed that the temperature of the outer wall of the furnace body rose above the design value (70 ° C. or less).
[0005]
[Problems to be solved by the invention]
The present invention has been made based on the above-described circumstances, and in addition to the design thickness of the furnace body constituted by the first refractory layer, the second layer, and the third heat insulation layer, the third heat insulation layer. In spite of melting damage on the inner wall surface (mainly the peripheral wall surface and ceiling wall surface) that is exposed to high temperature in the process of use by increasing the thickness of the material or adding a fourth heat insulation layer on the outside An object of the present invention is to provide a furnace body structure configured so that the outer wall surface of the furnace body can be maintained at a safe temperature or lower effectively and in the long term.
[0006]
[Means for Solving the Problems]
For this reason, in the present invention, in the furnace structure used when a high temperature atmosphere is generated inside by a heat source such as plasma and the object to be processed is thermally decomposed, the first using a refractory material corresponding to the inner wall surface. A second layer of heat transfer material corresponding to the outer side of the first layer, and a third layer of heat insulating material corresponding to the outer side of the second layer, respectively. The outer surface temperature of the third layer is designed to be equal to or lower than the legally safe temperature of 70 ° C. according to a predetermined temperature gradient corresponding to the temperature of the inner wall surface when the furnace body is laminated. The thickness of each of the first to third layers is defined, and the thickness of the third layer or the thickness of the fourth heat insulating layer provided outside thereof is determined by the inner wall surface in the process of using the furnace body. The required amount is increased or added in anticipation of surface melting of the first layer.
[0007]
In addition, as an embodiment of the present invention, it has been experimentally confirmed that the increase in the third layer or the thickness of the fourth heat insulating layer is 25 mm or more.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 schematically shows a waste treatment apparatus that has been proposed by the present inventor and can be applied to general waste, medical waste, and nuclear waste. 2 and 3 schematically show the furnace structure applied to this processing apparatus.
[0009]
As shown in FIGS. 1, 2, and 3, waste (processed material) of an appropriate size, for example, crushed / compressed into a chip shape or stored in a small container, is input here. It is put into the furnace 2 via the vessel 1. The furnace 2 has a horizontally long first partial space 21 in the lower part and a second partial space 22 located on the lower side of the charging device 1 via a funnel-shaped throttle part 23 (see FIG. 2). It has a structure that communicates. The charging device 1 includes an entrance door and an exit door (both not shown) that are opened and closed when one is opened and the other is closed. This is to prevent the inside of the furnace 2 from being directly opened to the outside (the previous processing section). In addition, if necessary, it is preferable that an internal atmosphere replacement means is linked to the charging device 1 to prevent external air from being introduced into the furnace 2.
[0010]
The first partial space 21 has a steeply inclined portion 24a corresponding to the lower side of the narrowed portion 23 on one end side thereof, and a floor portion 24 having a gently inclined portion 24b extending therefrom toward the other end. It communicates with the discharge part 25 via the outlet 24C provided on the other end side. The discharge part 25 opens to the outside through a door (not shown) from the lower part. The first partial space 22 has a pair of left and right plasma torches 26 and 27 (see FIG. 3) on one end side, and one plasma torch 28 on the other end side.
[0011]
The second partial space 22 communicates with the inlet of the next-stage combustion furnace 4 through a duct 29 in the upper part thereof. Air is supplied to the combustion furnace 4 by a pump 41, and a heating burner 42 is also provided. And the cooling tower 5 is connected to the exit. Inside the cooling tower 5, there is a bag filter 51, which communicates with the chimney 6.
[0012]
In such a configuration, in the partially reducing atmosphere in the first partial space 21, the inside of the furnace is heated to a high temperature of, for example, 1400 ° C. to 1500 ° C. by the plasma torch 26 to 28, and the generated heat flow is generated here. Then, the second partial space 22 is raised through the throttle portion 23. On the other hand, the waste (object to be processed) is thrown into the upper part of the second partial space 22 via the thrower 1.
[0013]
As a result, in the second partial space 22, the waste is thermally decomposed into a gaseous body containing combustible fine particles and a thermal decomposition residue. The former is supplied to the combustion furnace 4 of the next stage through the duct, touches the air supplied thereto, and acts by its own thermal energy and the heating burner 42 (about 400 to 800 °). C). Next, while being cooled by the cooling tower 5, the dust portion is separated through the bag filter 51, and the exhaust is discharged to the outside through the chimney 6. Further, the latter descends to the floor portion 24 of the first partial space 21 through the constricted portion 23, where it becomes a complete molten slag containing no undissolved material by melting. This is collected in a container or the like via the discharge unit 25 and supplied for reuse at a required location.
[0014]
In this furnace structure, a first layer 2A using a refractory material corresponding to the inner wall surface, and a heat transfer material (for example, powdered cement is consolidated corresponding to the outer side of the first layer 2A). The second layer 2B and the third layer 2C made of a heat insulating material (for example, ceramic) corresponding to the outside of the second layer 2B are laminated, respectively, Corresponding to the temperature of the wall surface, the thickness of the first to third layers is set so that the outer surface temperature of the third layer 2C is designed to be equal to or lower than the legally safe temperature of 70 ° C. by a predetermined temperature gradient. Each is stipulated. Note that the second layer 2B has a function of releasing thermal energy from the first layer 2A to avoid an excessive increase in the furnace temperature exceeding a predetermined value, and a heat loss due to the release of thermal energy to the outside. It is designed in consideration of its heat capacity (thickness) so as to serve as a heat retaining function for suppressing the heat. In particular, in the present invention, the thickness of the third layer or the thickness of the fourth heat-insulating layer 2D such as heat-resistant rock wool provided on the outside of the third layer is set on the inner wall surface in the process of using the furnace body. The necessary amount is increased or added in anticipation of surface melting of the first layer 2A.
[0015]
As an embodiment of the present invention, it is effective that the increase in the third layer 2C or the thickness of the fourth heat insulating layer 2D is 25 mm or more.
[0016]
With such a configuration, the temperature of the outer wall surface of the furnace body can be suppressed to a safe temperature of 70 ° C. or less even when used at a maximum temperature of 1700 ° C. for a considerable period of time.
Moreover, as in this embodiment, the layer thickness of the third layer 2C is increased, or by adding a fourth layer 2D provided outside the third layer 2C, the temperature of the outer wall surface of the furnace body is set to a safe temperature. Maintaining the first layer 2A on the inner side in that it prevents unnecessary heat dissipation, lowers running costs, demonstrates the economics of thermal energy, and can be easily modified after the furnace body is manufactured. This is superior to the case where the layer thickness of the second layer 2B is changed. In other words, at the design stage, setting the thickness of the first layer 2A and the thickness of the second layer to be larger than the planned design value in advance increases the equipment cost of the furnace body more than necessary (excessive However, it is advantageous to obtain safety in the third layer or the fourth layer in the actual use mode, because there is no waste in the equipment and in the subsequent response (modification). It is.
[0017]
【The invention's effect】
The present invention has been described in detail above. In the furnace structure used when a high-temperature atmosphere is generated inside by a heat source such as plasma and the workpiece is melted, a refractory material is provided corresponding to the inner wall surface. The first layer used, the second layer of heat transfer material corresponding to the outside of the first layer, and the third layer of heat insulating material corresponding to the outside of the second layer The outer surface temperature of the third layer is designed to be equal to or lower than the legally safe temperature of 70 ° C. by a predetermined temperature gradient corresponding to the temperature of the inner wall surface when the furnace body is used. As described above, the thicknesses of the first to third layers are respectively defined, and the thickness of the third layer or the thickness of the fourth heat insulating layer provided outside the third layer is defined as the use process of the furnace body. The required amount is increased or added in anticipation of surface melting of the first layer on the inner wall surface of
[0018]
Therefore, the outer wall surface of the furnace body can be maintained at a safe temperature or lower effectively and in the long term, despite melting on the inner wall surface (mainly the peripheral wall surface and ceiling wall surface) that is exposed to high temperatures during use. In addition, it can prevent unnecessary heat dissipation, lower running costs, and demonstrate the economics of thermal energy.
[Brief description of the drawings]
FIG. 1 is a schematic side view of a waste treatment apparatus according to the present invention.
FIG. 2 is a longitudinal side view of a furnace structure showing an embodiment of the present invention.
FIG. 3 is also a transverse plan view.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Charger 2 Furnace 2A 1st layer 2B 2nd layer 2C 3rd layer 2D 4th layer 21 1st partial space 22 2nd partial space 23 Restriction part 24 Floor part 25 Exhaust part 26-28 Plasma Torch 29 Duct

Claims (2)

In a furnace structure used when a high temperature atmosphere is generated inside by a heat source such as plasma and a workpiece is melted, a first layer using a refractory material corresponding to the inner wall surface, and the first layer A second layer of heat transfer material corresponding to the outer side of the layer and a third layer made of a heat insulating material corresponding to the outer side of the second layer are laminated, respectively, when the furnace body is used. The thickness of the first to third layers is designed so that the outer surface temperature of the third layer is designed to be equal to or lower than the legally safe temperature of 70 ° C. with a predetermined temperature gradient corresponding to the temperature of the inner wall surface of Furthermore, the thickness of the third layer or the thickness of the fourth heat insulating layer provided outside the third layer is defined as the surface of the first layer on the inner wall surface in the process of using the furnace body. Furnace structure characterized in that the required amount is increased or added in anticipation of melting damage. The furnace structure according to claim 1, wherein an increase in the third layer or a thickness of the fourth heat insulating layer is 25 mm or more.

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