JP2004167305A - Ultrahigh thermal decomposition furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrahigh thermal decomposition furnace which does not cause the thermal damage to a heating element even in such a state that thermal decomposition treatment is performed while supplying air into the furnace. <P>SOLUTION: The ultrahigh thermal decomposition furnace comprises a primary decomposition furnace 1 having a charging port 3 for a material to be treated to perform the primary high temperature thermal decomposition treatment of the material to be treated and a secondary decomposition furnace 2 arranged on the upper surface of the primary decomposition furnace 1 in a communication state. The heating coil 10 connected to an AC power supply is wound around the secondary decomposition furnace 2 in a non-contact state and heating plates 6 made of a heat-resistant magnetic material having a large number of gas treatment holes bored therein are arranged in the secondary decomposition furnate 2 at an appropriate interval over many stages. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ultra-high pyrolysis furnace, more specifically, medical waste, high-molecular waste plastics, etc., at an extremely high temperature while suppressing the generation of harmful substances such as dioxins, carbon dioxide, nitrogen compounds, and sulfur oxides. The present invention relates to an ultra-high pyrolysis furnace that performs combustion and pyrolysis.
[0002]
[Prior art]
Wastes, especially medical wastes and waste plastics, include dioxins, carbon dioxide, carbon monoxide, hydrocarbons, nitrogen compounds, sulfur oxides, etc. when subjected to general incineration at about 800 to 1200 ° C. Some substances emit harmful substances. Therefore, the waste that generates such harmful substances is burned and pyrolyzed at an extremely high temperature of 2000 to 2500 ° C.
[0003]
As an ultra-high thermal decomposition furnace used for the above-mentioned applications, there is a furnace having a configuration shown in FIG. This is composed of a primary cracking furnace 52 having an inlet 51 for a heat-treated material, and a secondary cracking furnace 53 connected to the upper part of the primary cracking furnace 52 in a communicating state and having an exhaust port 54 on the upper surface. Heating elements 55, 55a are provided at the bottom of each of the decomposition furnaces 52, 53. At the bottom of the secondary cracking furnace 53, a porous receiving plate 56 is arranged, on which a heating element 55a is placed. In addition, a blower 58 for generating an ascending airflow in the furnace is installed above the secondary cracking furnace 53.
[0004]
The heating elements 55 and 55a are formed by, for example, collecting a large number of balls formed with a metal coating such as chromium, molybdenum, aluminum, and magnesium on the surface of a granular material of a carbonaceous substance such as graphite, activated carbon, charcoal, and coal. An electric current is applied by applying the electrode 57 to cause arc discharge between the balls to generate heat at an extremely high temperature. The heat generation temperature is raised to about 2000 to 2500 ° C. (see Japanese Patent No. 3192395).
[0005]
Objects to be treated, such as medical waste and waste plastics, which have been introduced into the primary cracking furnace 52 from the inlet 51 are exposed to a high temperature of 2000 to 2500 ° C., thermally decomposed, gasified and raised, and the receiving plate 56. And enters the secondary cracking furnace 53. After that, the gas rises through the gap of the heating element 55 a, and when passing therethrough, is subjected to a high heat treatment again to decompose harmful gas such as dioxin contained therein and detoxify it, and is discharged from the exhaust port 54.
[0006]
By the way, some processing objects, such as used diapers, take a long time to process (it takes about four times as much as a normal processing object). In these processes, air is supplied into the primary cracking furnace 52 to accelerate the process, but in this case, the heating element 55a of the secondary cracking furnace 53 itself may burn. That is, since the main body of the heating element 55a is a carbonaceous substance whose ignition point is not sufficiently high, it is easy to burn out.
[0007]
[Problems to be solved by the invention]
In the case of the above-mentioned conventional ultra-high thermal decomposition furnace, there is a risk that the heating element of the secondary decomposition furnace may be burned out. Therefore, the present invention does not have such a problem, that is, the thermal decomposition treatment is performed while supplying air into the furnace. It is an object of the present invention to provide an ultra-high pyrolysis furnace in which a heating element does not burn out even in a situation where the heating is performed.
[0008]
[Means for Solving the Problems]
An ultra-high thermal decomposition furnace according to the present invention for solving the above-mentioned problems, a primary decomposition furnace having an inlet for an object to be processed and performing a primary high thermal decomposition treatment of the object to be processed, and an upper surface of the primary decomposition furnace A secondary cracking furnace is installed in communication with the secondary cracking furnace, and a heating coil connected to an AC power supply is wound around the secondary cracking furnace in a non-contact state. It is characterized in that heat-generating plates made of a heat-resistant magnetic material having gas processing holes are arranged in multiple stages at appropriate intervals.
[0009]
Preferably, the heat generating plate is made of molybdenum, and the gas processing holes are formed in an inclined state.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an ultra-high thermal decomposition furnace according to the present invention, which comprises a primary decomposition furnace 1 and a secondary decomposition furnace 2.
[0011]
On the side wall of the primary cracking furnace 1, a charging port 3 for charging an object to be processed is provided. A heating element 4 is arranged at the bottom of the primary decomposition furnace 1. The heating element 4 generates an ultra-high heat of about 2000 to 2500 ° C., for example, a metal coating of chromium, molybdenum, aluminum, magnesium, etc. on the surface of a carbonaceous substance such as graphite, activated carbon, charcoal, and coal. The electrode 5 for applying a current to the heating element 4 is arranged on the furnace wall of the primary cracking furnace 1.
[0012]
The secondary cracking furnace 2 is connected to the upper surface of the primary cracking furnace 1 so as to communicate with the primary cracking furnace 1. The secondary cracking furnace 2 has a smaller volume than the primary cracking furnace 1, and a plurality of heating plates 6 (six in the illustrated example) are arranged at appropriate intervals at the bottom at the bottom.
[0013]
The heat generating plate 6 is made of a high melting point magnetic material such as molybdenum or a tungsten alloy, and is, for example, a disk having a diameter of 300 mm and a thickness of 20 mm. For example, molybdenum having a melting point and a firing point of 2500 ° C. or more is suitable as a material of the heating element 6 used here.
[0014]
A large number (for example, 148 in the above size) of gas processing holes 7 having a hole diameter of about 10 mm are formed in the heat generating plate 6. The gas processing holes 7 are preferably inclined at an appropriate angle in order to increase the contact distance of the gas (see FIG. 4). An annular spacer 8 is interposed between the heat generating plates 6 to appropriately maintain a gap between the heat generating plates 6.
[0015]
The furnace wall 9 of the secondary cracking furnace 2 has sufficient heat insulation. For example, silica powder, sodium chloride, magnesium silicate, sodium salt, calcium powder, water, and, if necessary, metal powder such as chromium or molybdenum are mixed and kneaded. After forming into a shape, a product formed by drying is used.
[0016]
A heating coil 10 surrounding the heating plate installation portion of the furnace wall 9 in a non-contact state around the portion is provided. The heating coil 10 is connected to an AC power supply. The secondary cracking furnace 2 is provided with an exhaust port 11 on the upper surface, and a blower 12 for generating an ascending airflow in the furnace is installed on the upper part.
[0017]
In the above configuration, the material to be treated is charged into the primary cracking furnace 1 from the charging port 3, where it is burned and pyrolyzed by the heating element 4 at an ultra-high temperature of 2000 to 2500 ° C, leaving almost no ash. It is gasified without.
[0018]
The smoke containing this gas rises and flows into the secondary cracking furnace 2, where it is forcibly introduced into the gas processing holes 7 of the heating plate 6. The heat generating plate 6 generates heat of 2000 to 2500 ° C. by induction heating. That is, when an alternating current flows through the heating coil 10, a magnetic force is generated there, and an eddy current flows through each heat generating plate 6 due to the magnetic force, so that each heat generating plate 6 generates heat.
[0019]
As described above, the melting point and ignition point of molybdenum are 2500 ° C. or higher, and the heat generating plate 6 is entirely made of molybdenum. Therefore, the heat generating plate 6 has sufficient heat resistance in the secondary cracking furnace 2 and has no risk of burning. .
[0020]
The gas passes through the gas processing holes 7 of the heating plate 6 which has been heated to an extremely high temperature by the induction heating over several stages, during which harmful substances such as dioxins and nitrogen compounds are reliably thermally decomposed and harmless. And is drawn by the flow of air from the blower 12 and discharged from the exhaust port 11. When the gas processing hole 7 is inclined, it is possible to secure a sufficient contact time (processing time) with the gas while suppressing the thickness of the heat generating plate 6. Even if it is made of expensive material, it is not a burden.
[0021]
【The invention's effect】
The present invention is as described above, and in the ultra-high pyrolysis furnace according to the present invention, heat is generated by a heating plate made of a material having a high melting point such as molybdenum. In addition, there is an effect that various kinds of wastes can be completely pyrolyzed and converted into harmless gas and discharged without the heating element being burned.
[0022]
According to the third aspect of the present invention, even if the heat generating plate is made of a relatively expensive material such as molybdenum, it is possible to sufficiently secure the processing time of the harmful gas while suppressing the thickness thereof. There is an effect that can be suppressed.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a schematic configuration of an ultra-high pyrolysis furnace according to the present invention.
FIG. 2 is a cross-sectional view of a main part of the ultrahigh-temperature pyrolysis furnace according to the present invention.
FIG. 3 is a plan view of a heating plate in the ultrahigh-temperature pyrolysis furnace according to the present invention.
FIG. 4 is a sectional view taken along line AA in FIG. 3;
FIG. 5 is a longitudinal sectional view showing a schematic configuration of a conventional ultra-high thermal decomposition furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Primary cracking furnace 2 Secondary cracking furnace 3 Input port 4 Heating element 5 Electrode 6 Heating plate 7 Gas processing hole 9 Furnace wall 10 Heating coil 11 Exhaust port 12 Blower

Claims (4)

A primary cracking furnace having an inlet for the object to be processed and performing a primary high thermal decomposition treatment of the object to be processed; and a secondary high heat A heating coil connected to an AC power source is wound around the secondary cracking furnace in a non-contact state, and a number of gas processing holes are formed in the secondary cracking furnace. An ultra-high pyrolysis furnace, wherein a plurality of heating plates made of a magnetic material having a high melting point are provided in multiple stages at appropriate intervals. The ultrahigh pyrolysis furnace according to claim 1, wherein the heating plate is made of molybdenum. 3. The ultrahigh pyrolysis furnace according to claim 1, wherein the gas processing hole is formed in an inclined state. 4. The ultra-high thermal decomposition furnace according to any one of claims 1 to 3, wherein the heating plates are arranged in six stages.

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