JPH10286544A - Apparatus for carbonization-reduction of waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat waste efficiently by using high-frequency to carbonization- reduction temperatures in an apparatus for carbonization-reducing waste by using a rotary kiln. SOLUTION: The apparatus is provided with a rotating drum 2 slightly inclining from the horizontal axis, an inflow side partition wall 3 and an outflow side partition wall 4 fixed and closing the both ends of the rotating drum, a waste feeder penetrating the inflow side partition wall 3, a discharging conveyer connecting to a discharging port 33 opening to the bottom part of the outflow side partition wall 4, a columnar heat apparatus 5 supported by penetrating the both partition walls 3, 4, an incombustible gas-feeding port 35 provided on at least one side of the partition walls 3, 4, and a reduction gas-exhausting cylinder 31. The heating apparatus 5 is provided with a metallic shell cylinder 23, a high-frequency coil 25 composed of a hollow wire provided with keeping a slight gap to the inside face of the metallic shell cylinder 23, and an electrically and thermally insulating material 26 supporting the high-frequency coil. Accordingly, high-frequency current is applied to the coil 25 and cooling water is flowed into a hollow hole of the hollow wire. The metallic shell cylinder 23 is heated at high temperature by induction heating action.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for carbonizing and reducing waste using a rotary furnace, and more particularly to a heating means for drying and carbonizing waste and decomposing harmful substances such as dioxin in a reducing atmosphere. The present invention relates to a heating device characterized in that:

[0002]

2. Description of the Related Art Waste is usually incinerated in most cases. In such incineration, a large amount of air is required to supply oxygen because combustion is performed by oxygen (in the air). Is 21% and the excess air ratio is about 1.8 times). As a result, a large amount of combustion exhaust gas is generated, and harmful by-products such as nitrogen oxides, sulfur oxides, hydrogen chloride, and carbon dioxide gas are generated. This is disadvantageous in terms of cost.

Further, as a device for completely burning waste without using a combustion aid such as heavy oil and suppressing generation of offensive odor and harmful combustion gas, the waste is dried by microwave heating under reduced pressure to remove moisture. An incinerator in which waste waste is sent to a combustion chamber for oxygen incineration is disclosed in Japanese Patent Application Laid-Open No. Hei 7-233931. In this drying apparatus, waste containing water is heated and dried from the inside by microwave heating in a drying chamber placed in front of the combustion chamber, and then transferred from the drying chamber to the combustion chamber for incineration. The use of microwave heating as a drying means has been conventionally used for drying wood, for example.

Japanese Patent Laid-Open Publication No. Sho 59-109131 proposes a device for drying tea leaves using a rotary kiln type drying furnace using microwave heating. The heating principle in these devices is to heat an object to be heated from the inside by using an induction action by a high-frequency current, and the object to be heated can be uniformly dried to the inside (not only the surface). There is a feature.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus which can dry and heat a waste material to a higher temperature and carbonize and reduce it without generating a bad odor or a harmful gas. It is another object of the present invention to provide a waste carbonization / reduction apparatus provided with a heating means capable of heating waste to a carbonization / reduction temperature more efficiently using high frequency.

[0006]

According to a first aspect of the present invention, there is provided an apparatus for carbonizing and reducing waste, comprising: a rotating drum 2 supported at a slight inclination from a horizontal axis; and a fixed inflow-side partition for closing both ends of the rotating drum. A feeder 28 that feeds waste into the rotating drum 2 through the inlet-side partition 3 and a discharge conveyor 34 that communicates with a discharge port 33 that opens at the bottom of the outlet-side partition 4; A cylindrical or polygonal heating device 5 that penetrates the inflow-side partition wall 3 and the outflow-side partition wall 4 and is supported by the partition walls 3 and 4 is provided on at least one of the inflow-side partition wall 3 and the outflow-side partition wall 4. The heating device 5 comprises a metal shell 23 and a high-frequency coil 25 composed of a hollow wire arranged at a slight distance from the inner surface of the metal shell, Hold this high frequency coil in place And a rim of the heat insulating material 26, together with the high-frequency current is applied to the coil 25, in the hollow hole cooling water is characterized in being passed through.

According to a second aspect of the present invention, in the waste carbonizing and reducing apparatus according to the first aspect, the feeder 28 and the discharge conveyor 34 are a screw feeder and a screw conveyor.

[0008]

The waste 36 supplied into the rotary drum 2 by the feeder 28 due to the rotation of the rotary drum 2 whose axis is inclined,
It is slowly transferred to the outflow side while being stirred. When a high-frequency current is applied to the high-frequency coil 25, the metal shell 23 is heated by the induction heating action. The waste 36 is heated mainly by the radiant heat from the metal shell 23 while moving on the upstream side portion in the rotary drum 2, and the moisture evaporates from the outer surface and dries. The waste whose outer surface is dried is further heated by radiant heat from the metal shell 23 and carbonized and reduced. The reducing gas generated by the carbonization / reduction together with the metal shell 23 promotes the drying of the waste 36 and the carbonization / reduction. In addition, the water inside the waste evaporates due to the carbonization and reduction, and the carbonization and reduction proceeds. The carbonized material is slowly transferred to the outflow side while being stirred with the rotation of the rotary drum 2, and the remaining carbonized material is discharged to the outlet 33 Through the discharge conveyor 34. During the unloading process by the discharge conveyor 34, the carbonized material is cooled. Further, the heat generated by the wires of the high-frequency coil 25 caused by the current-carrying resistance is cooled by the water flowing through the hollow holes.

In the apparatus according to the present invention, the induction heating action of the high-frequency current, that is, the flow of the high-frequency current through the high-frequency coil 25 causes the electric resistance of the eddy current generated in the metal shell 23 as a conductor to raise the temperature of the metal shell 23 to a high temperature. By utilizing the heating, the waste 36 is dried and carbonized / reduced, and the waste can be efficiently heated to a high temperature required for carbonization / reduction. In addition, uniform drying and combustion can be performed by the stirring action by the rotation of the rotating drum 2, and the amount of electricity supplied to the high-frequency coil 25 is controlled according to the furnace temperature, so that the carbonization / reduction temperature can be accurately adjusted to a desired temperature. Can be maintained.

The waste 36 in the rotary drum 2 is heated by the cylindrical or polygonal column heating device 5 disposed in the rotary drum 2 substantially in parallel with the rotary drum, so that heat is less radiated to the outside. , Improve thermal efficiency. By holding the high-frequency coil 25 with the insulating heat insulating material 26, heat radiation to the inside of the metal shell 23 can also be suppressed.

In the case where a screw feeder and a screw conveyor are used as the feeder 28 and the discharge conveyor 34, waste and ash are filled and conveyed inside the conveyor, so that the feeder and the discharge conveyor can be used without using a special sealing device. Air can be prevented from flowing into the rotating drum through the space. During the carbonization and reduction, the inside of the furnace is maintained at a slightly positive pressure in order to prevent the inflow of air.

[0012]

Embodiments of the present invention will be described below with reference to embodiments shown in the drawings. 1 is a sectional view of a rotary furnace, FIG. 2 is a sectional view of a part A in FIG. 1, FIG. 3 is a side view of the entire apparatus, and FIG.

The rotary furnace 1 comprises a rotary drum 2, inflow and outflow partition walls 3 and 4, and a heating device 5. The rotating drum 2 has thick flanges 6 on both sides, and is supported rotatably by supporting the flanges 6 with rollers 8 (8a, 8b) provided on a gantry 7. The roller 8 is slightly higher than the roller 8a on the upstream side, so that the rotary drum 2 is inclined so as to be slightly lower from the upstream side to the downstream side. A sprocket 9 is also fixed to the rotating drum 2, and the rotating drum 2 is rotationally driven by connecting an output shaft of an electric motor 10 mounted on the gantry 7 and the sprocket with a chain.

The rotary drum 2 has a three-layer structure in which a heat insulating material layer 12 and a refractory material layer 13 are provided on the inner surface of a cylindrical iron plate 11 which is a main strength member. A heat insulating material 14 is mounted where no sprocket 6 and sprocket 9 are mounted. An axially elongated scraping blade 15 for scraping up waste is mounted inside the rotating drum 2.

The inflow-side partition wall 3 and the outflow-side partition wall 4 that close both ends of the rotary drum 2 are fixedly provided on a gantry 7.
Between the inflow-side bulkhead 3 and the outflow-side bulkhead 4 and the rotary drum 2,
Rotary seals 16 and 17 are provided to prevent gas leakage from inside the furnace. The rotary seals 16 and 17 are formed by winding a heat-resistant string-like seal material, and are held between the pressing plates 18 and 19 in the axial direction to hold the rotary seals 16 and 17.

The heating device 5 has a cylindrical shape and has both ends provided on the inflow-side partition 3 and the outflow-side partition 4 with heater mounting holes 20 and 21.
Is supported in a state where it passes through. The cylindrical heating device 5 is fixed in the axial direction on the inflow side partition 3 side, and can be pulled out to the outflow side partition 4 side for inspection or the like. Mounting hole 2
1 has a slightly larger diameter, and is provided with a rotary seal 22 similar to that provided between the outflow-side partition 4 and the rotary drum 2 in order to prevent the gas in the furnace from leaking from the gap.

The heating device 5 has a high-frequency coil 25 around which a copper pipe is wound with a slight gap 24a disposed between the metal shell tube 23 and the inside of the cylindrical metal shell tube 23. Is filled with a heat insulating material 26 made of ceramic fiber. A high-frequency current is applied to the high-frequency coil 25 from a high-frequency oscillator, and cooling water is supplied to the hollow hole of the copper pipe.

A screw feeder 28 provided with a hopper 27 at a base end is provided on a pedestal 7a on the upstream side of the rotary furnace 1, and a tip of the screw feeder penetrates the upstream partition 3 of the rotary furnace. It is open in the rotating drum 2. In order to secure an arrangement space for the screw feeder 28, the heating device 5 is slightly offset from the center of the rotary furnace 1 as shown in FIG. On the side of the hopper 27 (on the front side of FIG. 3),
A work table 29 and a ladder 30 for ascending the work table are provided. Above the inflow-side partition 3, a reducing gas exhaust pipe 31 communicating with the inside of the rotary furnace is provided.

The outflow-side partition 4 has a vacant space 32 in which a heat insulating material layer 12 and a refractory material layer 13 similar to those provided on the rotary drum 2 are provided on the wall surface.
The outflow-side end of the rotary drum 2 is supported in a state where it is slightly inserted into the empty space. A discharge port 33 is provided at the lower end of the empty room 32, and a discharge screw conveyor 34 is connected to this discharge port. The discharge screw conveyor 34 extends obliquely upward, and discharges the carbon material falling from the discharge port 33 so as to lift diagonally upward. The outlet side partition wall 4 is provided with a non-combustible gas supply port 35 communicating with the inside of the furnace.

The waste to be carbonized and reduced is hopper 2
7 and fed into the rotary drum 2 by the screw feeder 28. The rotating drum 2 is slowly driven to rotate counterclockwise in FIG. Incombustible gas supply port 35
After that, a non-combustible gas is supplied into the furnace, a high-frequency current is applied to the high-frequency coil of the heating device 5, and cooling water flows through the hollow hole of the copper pipe. The metal shell 23 of the heating device is induction-heated by the action of the high frequency current flowing through the high-frequency coil 25, and the heat of the metal shell 23 is transferred to the waste in the rotary drum 2 mainly by radiation and convection to carbonize the waste.
To reduce. The carbonization / reduction temperature is controlled by a current value flowing through the high-frequency coil 25. By the rotation of the rotary drum 2, the waste in the rotary drum is stirred such that the bottom is scraped up to the upper layer, and is uniformly carbonized and reduced. By heating in the non-oxidizing atmosphere, the waste 36 is carbonized and reduced.

Due to the inclination of the rotary drum 2, the waste in the rotary drum moves to the outflow side while being stirred. Then, the waste that has moved to the empty room 32 of the outflow side partition wall falls through the discharge port 33 and is discharged by the discharge screw conveyor 34. The hopper 27 is open upward, and the screw feeder 28 and the discharge screw conveyor 34 are in a state of being filled with the carbon material because the discharge screw conveyor 34 sends the carbon material upward. Furnace gas is prevented from flowing out of the hopper 27 and the discharge screw conveyor 34.

In the apparatus of the present invention, as described in the above embodiment, the waste continuously supplied from the feeder is
It is carbonized and reduced in a rotary furnace and is continuously discharged by a discharge conveyor, so that the waste can be uniformly carbonized and reduced and the control of the carbonization and reduction temperature is easy. In addition, by employing the heating device having the structure of the present invention, high-temperature heating is possible, carbonization and reduction can be accurately controlled, and heat leakage to the outside of the furnace is reduced, thereby improving thermal efficiency. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rotary furnace according to an embodiment.

FIG. 2 is a sectional view of a portion A in FIG.

FIG. 3 is an overall side view of the apparatus according to the embodiment.

FIG. 4 is an overall plan view of the apparatus of the embodiment.

[Explanation of symbols]

 2 Revolving drum 3 Inlet-side bulkhead 4 Outlet-side bulkhead 5 Combustion device 23 Metal shell 25 High-frequency coil 26 Insulating heat insulating material 28 Feeder 31 Reducing gas exhaust 33 Outlet 34 Exhaust conveyor 35 Incombustible gas supply

Claims (2)

[Claims] 1. A rotary drum supported slightly inclined from a horizontal axis.
(2) and a fixed inflow-side bulkhead that closes both ends of this rotating body
(3) and the outlet bulkhead (4), the feeder (28) that penetrates the inlet bulkhead (3) and supplies waste into the rotating drum (2), and an opening at the bottom of the outlet bulkhead (4). The discharge conveyor (34) communicating with the discharge outlet (33), and the cylindrical or polygonal column supported by the partition walls (3, 4) through the inlet partition wall (3) and the outlet partition wall (4). Heating device (5), inlet bulkhead (3) and outlet bulkhead
(4) a non-combustible gas supply port (35) and a reducing gas exhaust pipe (31) provided in at least one of the
(5) is a high-frequency coil (25) consisting of a metal shell (23) and a hollow wire arranged at a slight distance on the inner surface of the metal shell.
And an insulating heat insulating material (26) for holding the high-frequency coil in a predetermined position, and a high-frequency current is applied to the coil (25), and cooling water is passed through the hollow hole. Characterized by a carbonization and reduction device for waste. 2. The waste carbonization / reduction apparatus according to claim 1, wherein the feeder (28) and the discharge conveyor (34) are a screw feeder and a screw conveyor.