JP2002192108A - Heating treatment apparatus for powder waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means capable of efficiently removing dioxins or the like contained in main ashes and fly ashes generated in a waste incinerator and efficiently detoxicating the ashes. SOLUTION: The heating treatment apparatus comprises a vertical type cylinder having a heating part in the lower part of the side face, a gas blowing-in inlet for fluidizing powder wastes and an outlet for heated powder wastes both formed in the bottom part, and an inlet for throwing powder wastes through and an outlet for the gas both formed in the upper part. In the heating treatment apparatus, the inlet for throwing powder wastes through is formed in the vicinity of the upper face of the fluidized layer of the powder wastes to efficiently remove dioxins and detoxicate ashes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for powdery waste, and more particularly, to a heat treatment apparatus for heating and volatilizing and removing dioxin and the like contained in refuse incineration ash and the like.

[0002]

2. Description of the Related Art Recently, it has been found that extremely toxic organic compounds such as dioxins are generated at the time of incineration of refuse, and environmental pollution due to this is a serious problem. This dioxin is contained in the incineration exhaust gas discharged from the refuse incineration facility, fly ash collected from the exhaust gas, and main ash extracted from the incinerator.

[0003] Japanese Patent Publication No. 6-38863 discloses a method of decomposing this dioxin with various catalysts. Among them, a method of heating and gasifying activated carbon used for collecting dioxin to gasify and catalytically decompose or a method of heating fly ash in an oxygen-deficient state to catalytically decompose is disclosed. The specific structure of the device is not shown.

[0004] Japanese Patent No. 2512665 (Japanese Unexamined Patent Publication No.
JP-A-159646) discloses an incineration ash treatment method in which incineration ash discharged from a refuse incineration facility is heated to decompose organic chlorine compounds contained in the incineration ash. Heat at 550 ° C., then 25
Disclosed is a method for treating incineration ash, which is characterized by rapidly cooling to 0 ° C. or lower. The apparatus used for this incineration ash treatment is of a horizontal rotary kiln type.

Japanese Patent Application Laid-Open No. 2000-16844 also discloses that a material containing dioxin is heated to a temperature higher than the boiling point of dioxin, a gas containing volatile dioxin is introduced into a rotary kiln for sintering cement, and heat generated during sintering of cement. Discloses a method for thermally decomposing dioxin.

[0006]

The conventional apparatus for vaporizing and decomposing dioxin contained in main ash and fly ash generated by incineration of refuse is a rotary kiln. Disassembly is not easy, which has led to an upper bound on equipment costs.

An object of the present invention is to provide a means capable of efficiently removing dioxins and the like contained in main ash and fly ash generated in a refuse incinerator, and thereby efficiently detoxifying the ash.

[0008]

Means for Solving the Problems The present inventors have studied to solve the above-mentioned problems, and as a result, the detoxification treatment of dioxin contained in main ash and fly ash generated in a refuse incinerator is basically performed. Finally, it was concluded that it is preferable to divide it into vaporization and decomposition of dioxins and the like. As a device for vaporizing and removing dioxin, a device that blows gas from the bottom of a vertical cylinder and heats it while flowing ash to vaporize dioxin was the most efficient. Then, while continuing the operation test using this fluidized bed forming type heater, the following was noticed.

In other words, this heater has a structure in which heating is performed from the lower portion of the side surface, gas is blown in from the bottom portion, and dioxin or the like vaporized is discharged from the upper portion. As a result, this gas comes into contact with unheated main ash and fly ash introduced from above, and the dioxin contained in this gas solidifies and adheres to its surface, returning to the original fluidized bed. I thought it might be. As a countermeasure, there is a method in which heating is performed before the main ash or fly ash is thrown in. However, this requires an additional heater and has poor thermal efficiency. Therefore, as a result of further study, it was considered that a guide or the like was attached to the inlet of the main ash or fly ash, and the ash was directly sent to the fluidized bed without coming into contact with the gas to be discharged. Experiments have confirmed that this guide tube is extremely effective. Since this guide tube has a main ash or fly ash input port installed near the upper surface of the fluidized bed, the same effect can be obtained even if this input port is externally connected to that portion. Also,
It is effective not only for main ash and fly ash but also for vaporization and removal of dioxin from activated carbon or the like adsorbing dioxin.

The present invention has been made based on these findings. The lower part of the side surface of the vertical cylinder is a heating part, and the bottom part is provided with a gas inlet for flowing powdery waste and a heat-treated powdery waste. In a heat treatment apparatus in which a waste outlet is provided, and a powdery waste input port and the gas outlet are provided at an upper part, the powdery waste input port is located near an upper surface of a fluidized bed of the powdery waste. The present invention relates to a powdery waste heat treatment apparatus characterized in that the heat treatment apparatus is provided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vertical cylinder is for containing powdery waste to be heat-treated, and may be a straight cylinder or a different-diameter cylinder having a tapered portion and an upper or lower portion having a shorter diameter. . The upper and lower sides are closed and the whole has a closed structure.
The upper and lower surfaces are flat, curved, and conical. Although the volume is designed in accordance with the amount or the like of the powdery waste to be processed, is usually 0.2 to 10 m ³ approximately.

The lower part of the side surface of the heater composed of the vertical cylinder is a heating part for heat-treating the powdery waste. The heating method may be any of a method of heating from the outer surface of the cylinder, a method of providing a heater inside, and a method of using gas for flowing powdery waste as hot air.

The gas for flowing the powdery waste also exerts a transfer function of discharging dioxin and the like vaporized by heating, and it is preferable to use air, nitrogen, incineration exhaust gas and the like. The gas inlet is provided at the bottom of the heater, that is, at the bottom or the lower end of the side surface. A plurality of gas inlets can be provided according to the scale of the heater, that is, the volume of the vertical cylinder, and as shown in FIG. 2, a single or double or more ring sparger type is also preferable. As shown in FIG. 3, a perforated plate (perforated plate) 32 is provided in the gas inlet 3 to make the gas blowout uniform, and the powdery waste is supplied to the gas inlet 3.
It can be prevented from entering.

An outlet for the heat-treated powdery waste is also provided at the bottom of the heater, that is, at the bottom or the lower end of the side surface.

The powdery waste input port is provided at the upper part of the heater. In the present invention, it is provided near the upper surface of the fluidized bed of the powdery waste formed in the heater. In this case, as shown in FIG. 1, a guide pipe 53 may extend downward from a connection end 52 of the powdery waste input pipe 51, and as shown in FIG. It may be connected near the upper surface of the fluidized bed on the side of the vessel. In that case, a guide tube 53 can be provided as necessary to move the input portion of the powdery waste to the center side inside the heater. The distal end of the guide tube 53 is bent downward, but need not be bent. The upper surface of the fluidized bed of the powdery waste can be controlled by the supply speed and the discharge speed of the powdery waste, the amount of gas blown, and the like.
Providing the powdery waste inlet near the upper surface of the fluidized bed means that the higher it is, the more the solidified adhering amount of vaporized dioxin etc. increases, and the lower it is, the more insufficient removal of vaporization of dioxin etc. This is because the rate of discharge increases, and the input port may be set in a range where these problems do not occur.

The gas outlet is also provided at the upper part of the heater, but if the gas filter is too close to the upper surface of the fluidized bed, the amount of scattered powdery waste increases and the dust filter becomes clogged immediately. Is preferred. If necessary, a dust filter or a dust removing device such as a cyclone is provided at the gas outlet.

It is preferable to provide a stirrer to assist in the formation of the fluidized bed and to prevent powdery waste from adhering to the inner wall of the heater.

The powdery waste from which dioxins and the like have been removed by the heat treatment apparatus of the present invention can be directly discarded or effectively used. On the other hand, dioxin removed by vaporization can be decomposed by a known method, or returned to an incinerator where it can be thermally decomposed.

[0019]

FIG. 1 shows a powdery waste heater according to one embodiment of the present invention. In this heater, the lower portion of the side surface of the vertical cylinder 1 is a heating portion 2, and the bottom surface is connected to a gas supply pipe 31 for flowing powdery waste and a discharge pipe 41 for heat-treated powdery waste. Each opening is a gas inlet 3 and a powdery waste outlet 4.

A powdery waste input pipe 51 and a gas discharge pipe 61 are connected to the upper surface of the vertical cylinder 1. A guide pipe 53 extends downward from a connection end 52 of the powdery waste input pipe 51, and lowers the powdery waste input port 5 from the connection end 52 to the upper surface 71 of the fluidized bed 7 of the powdery waste. . The connection end to the upper surface of the gas discharge pipe 61 is the gas outlet 6. The gas outlets 6 are provided at two places, and both have a dust filter 62 mounted inside the heater. This gas outlet 6 is connected to a switching valve 6 provided in a gas exhaust pipe 61.
3 and can be used alternately.

A stirrer 8 comprising a multistage stirring blade 81 is provided inside the heater. The stirrer 8 stirs the powdery waste and prevents it from adhering to the inner wall of the heater.

A fly ash containing dioxin was charged into the above-mentioned heat treatment apparatus, heated at 420 ° C., and a comparison was made between the case where the guide tube 53 was provided and the case where the guide tube 53 was not provided. Table 1 shows the obtained results.
Shown in

[0023]

[Table 1]

[0024]

According to the present invention, it is possible to effectively prevent a decrease in the gas temperature around the dust removing device installed above the fluidized bed in the heater, and as a result, to improve the volatilization efficiency,
It is possible to reduce the energy required for heating during the heat treatment and the blowing gas used for promoting volatilization. In addition, since dioxin-related substances and other organic substances that cause dioxin resynthesis can be effectively volatilized and removed, resynthesis of dioxin in the treated waste can be achieved without a rapid cooling step.

[Brief description of the drawings]

FIG. 1 is a diagram showing the structure of a heat treatment apparatus according to one embodiment of the present invention.

FIG. 2 is a bottom perspective view showing an example in which a gas spout uses a ring sparger.

FIG. 3 is a bottom perspective view showing an example in which a perforated plate is used for a gas inlet.

FIG. 4 is a partial perspective view showing an example in which a powdery waste input port is connected to a side surface of a heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vertical cylinder 2 ... Heating part 3 ... Gas inlet 31 ... Gas inlet pipe 32 ... Perforated plate 4 ... Powder waste outlet 41 ... Discharge pipe 5 ... Powder waste input port 51 ... Input pipe 52 ... Connection End 53: Guide tube 6: Gas outlet 61: Discharge tube 62: Dust filter 63: Switching valve 7: Fluidized bed 71: Upper surface 8: Stirrer 81: Stirrer blade

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Iwa ▲ saki ▼ Toshihiko 1-2-1 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 3K061 NA01 4D004 AA36 AB07 CA22 CA50 CB31 CB42 DA02 DA20

Claims (2)

[Claims] 1. A lower portion of a side surface of a vertical cylinder is a heating portion, a gas inlet for flowing powdery waste and a powdery waste outlet heated are provided at a bottom portion, and a powdery waste at an upper portion. In a heat treatment apparatus provided with an input port and an outlet for the gas, the powdery waste input port is provided near an upper surface of a fluidized bed of the powdery waste, wherein the powdery waste heat treatment is provided. apparatus 2. The powdery waste heat treatment apparatus according to claim 1, wherein the powdery waste input port moves up and down in accordance with the fluctuation of the upper surface of the fluidized bed.