JPH11148631A - Incinerator and incinerating method for contaminated soil or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce high grade fuel, e.g. gas or petroleum, required for incineration by adding high calorie waste to contaminated soil, and the like, and then incinerating them. SOLUTION: Contaminated soil 12 to be incinerated is thrown along with high calorie waste 14, e.g. waste plastic, into the body 21 of a fluidized bed incinerator 20 through a hopper 22. The contaminated soil 12 and the high calorie waste 14 thrown into the body 21 are fluidized along with sand in the fluidizing chamber 24 by means of heated air and then crushed. At the same time, the contaminated soil 12 is subjected to incineration at a constant temperature of 950 deg.C or below through combustion of the high calorie waste 14 fired by a heating burner 26. Consequently, contaminants are volatilized and organic substances are decomposed and evaporated. After incineration, the contaminated soil 12 and coarse inflammable matters 16 contained in the high calorie waste 14 are fed through a discharge pipe 28 to a vibratory sieve 29 and separated from sand. The sand is returned back to the fluidized bed and used in the next incineration process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for incineration and purification of contaminated soils, and more particularly to a method and apparatus for incineration and purification of contaminated soils containing contaminants such as organic halogen compounds.

[0002]

2. Description of the Related Art In recent years, treatment of contaminated soil and sludge (hereinafter referred to as contaminated soil) generated by industrial activities has become a major problem. Conventionally, such contaminated soils have been incinerated. However, contaminated soils
Unlike waste such as municipal waste, it does not burn naturally, so its incineration requires high-grade fuels such as gas and oil. On the other hand, incineration of contaminated soils containing an organic halogen compound such as polyvinyl chloride may generate a hardly decomposable contaminant such as dioxin, and there is a concern that such a substance may affect the environment. In order to prevent the generation of hard-to-decompose pollutants, it is necessary to incinerate contaminated soil at a considerably high temperature, which contributes to further increase in high-grade fuel required for incineration of contaminated soil.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and is intended to incinerate contaminated soils capable of greatly reducing the high-grade fuel required for incineration of contaminated soils. It is an object to provide a purification method and an incineration purification device. Furthermore, it is an object of the present invention to provide a method and apparatus for incineration and purification of contaminated soil that can separately and effectively use the energy used for incineration of contaminated soil and treatment of hardly decomposable pollutants such as dioxins. I do.

[0004]

The method for incineration and purification of contaminated soils according to the present invention is characterized in that high-calorie waste is added to the contaminated soils for incineration. Further, in the above method, the exhaust gas generated by the incineration is further heated to completely decompose the hardly decomposable pollutants in the exhaust gas, and the heated exhaust gas is used as a separate heat source. .

[0005] Further, the incineration and purification apparatus for contaminated soils according to the present invention includes an incineration apparatus for incinerating contaminated soils by adding high-calorie wastes, and a method for heating exhaust gas generated from the incineration apparatus to be contained in the exhaust gas. The exhaust gas heating device for completely decomposing the decomposable pollutants and a heat engine using the exhaust gas heated by the exhaust gas heating device as a heat source are provided.

According to the present invention having the above-described structure, it is possible to save fuel required for incineration of the contaminated soil by burning the contaminated soil with high calorie waste. Further, by further heating the exhaust gas generated by the incineration, it becomes possible to completely decompose hard-to-decompose contaminants such as dioxin contained in the exhaust gas generated by the incineration of high calorie waste and contaminated soil. As a result, by using mixed waste plastic containing an organic halogen compound such as polyvinyl chloride as high calorie waste, it becomes possible to simultaneously treat difficult-to-treat materials and contaminated soil. Furthermore, by separately using the heated exhaust gas as a heat source, it becomes possible to efficiently reuse high energy used for incineration and heating.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an incineration and purification apparatus for contaminated soils according to the present invention. In FIG. 1, an incineration purification apparatus 10 includes a fluidized bed incinerator 20 for incinerating contaminated soils,
A cyclone 30 for separating solid particles from exhaust gas generated by incineration of contaminated soil, a secondary heating chamber 40 for further heating the exhaust gas, and steam generated using the exhaust gas heated in the secondary heating chamber 40 as a heat source. In addition, a boiler 50 for supplying heated air to the fluidized bed incinerator 20 is provided.

The fluidized bed incinerator 20 includes a main body 21 for containing contaminated soil and the like to be incinerated, and a contaminated soil 12 and high-calorie waste 14 such as waste plastic in the main body 21.
Is provided with a hopper 22 for charging the hopper. An air-permeable partition 23 is provided inside the main body 21, whereby a flow chamber 24 for heat-treating the contaminated soil 12 is provided inside the main body, and lower air for supplying heated air to the flow chamber 24. A chamber 25 is formed. Sand is housed in the flow chamber 24 as a heat medium, and when heated air is pumped into the flow chamber 24 from the boiler 50 through the lower air chamber 25 and the partition 23, the contaminated soil introduced into the flow chamber 24 is conveyed. Class 12 and high calorie waste 14 are fluidized with sand and ground. The flow chamber 24 is provided with a heating burner 26 for ignition or incineration temperature control, and a fuel supply passage 27 for supplying fuel such as gas or oil to the heating burner 26.

At the bottom of the main body 21, a discharge pipe 28 for discharging coarse incombustible substances contained in the heat-treated contaminated soil 12 and high calorie waste 14 is provided. The discharge pipe is provided with a vibrating sieve 29 for separating coarse foreign matters and sand.
, And is configured so that the coarse contaminants 16 are discharged to the outside and the sand is returned to the fluidized bed. Also, body 2
A gas outlet 21a for discharging exhaust gas and solid particles generated by the combustion of contaminated soils is formed in the upper part of the fuel cell. In such a fluidized bed incinerator 20, when ignited by the heating burner 26, the contaminated soil 12 flowing in the fluidized chamber together with the sand is incinerated by the combustion heat of the high calorie waste 14.

A cyclone 30 is provided on the downstream side of the fluidized bed incinerator 20 in the conveying direction of the exhaust gas. An exhaust gas inlet 30 a through which exhaust gas generated in the fluidized bed incinerator 20 is guided is formed at an upper portion of the side wall of the cyclone 30. Further, a centrifugal separation mechanism (not shown) for separating solid particle components contained in the exhaust gas is provided inside the cyclone 30. At the bottom of the cyclone 30 is provided a solid particle recovery unit 31 for recovering the solid particles separated by the centrifugal separation mechanism, and the solid particles separated from the exhaust gas are recovered as purified soil 33. Cyclone 3
An exhaust gas outlet 30b for discharging an exhaust gas component from which solid particles have been removed is formed at the top of 0.

A secondary heating chamber 40 for performing secondary heating of the exhaust gas passing through the cyclone 30 is provided downstream of the cyclone 30 in the direction of transport of the exhaust gas. The secondary heating chamber 40 is provided with an afterburner 41 for performing secondary heating of the exhaust gas and a fuel supply passage 42 for supplying a fuel such as gas or oil to the afterburner 41.
Is provided. In the secondary heating chamber 40, the exhaust gas is heated to 1000 ° C. or higher, preferably 1200 ° C. or higher.

[0012] Further downstream of the secondary heating chamber 40, the boiler water 5 using the high temperature exhaust gas from the secondary heating chamber 40 as a heat source.
A boiler 50 for generating steam 52 from 1 is provided. The steam 52 is sent to an adjacent power generation device 60 and used for power generation. Further, outside air 53 is introduced into the boiler 50 and the outside air heated in the boiler 50 is supplied to the lower air chamber 25 of the fluidized bed incinerator 20.
Is provided with a blower 54 for pressure feeding. Furthermore,
The boiler 50 is provided with a gas cleaning device 58 for finally purifying exhaust gas used as a heat source and an exhaust gas suction blower 55 for discharging the exhaust gas to the outside. The exhaust gas is configured to be released from the chimney 56 as clean gas 57 into the atmosphere.

Hereinafter, a method for incineration and purification of contaminated soils using the above apparatus will be described. Contaminated soil 12 to be incinerated
The products are put into the body 21 of the fluidized bed incinerator 20 via the hopper 22 together with the high-calorie waste 14 such as waste plastic. The contaminated soils 12 and high-calorie wastes 14 introduced into the main body 21 are fluidized together with sand by heated air in a fluidizing chamber 24, and pulverized. At the same time, the contaminated soil 12 is incinerated at a constant temperature of 950 ° C. or lower by burning the high-calorie waste 14 ignited by the heating burner 26. As a result, the contaminated soils 12 and the high-calorie wastes 14 are uniformly heated, and the pollutants are volatilized.
Organic substances are decomposed and evaporated. After incineration, contaminated soil 12
Incombustibles 16 contained in high calorie waste 14
Is separated from the sand by a vibrating sieve 29 in a discharge pipe 28,
The sand is returned to the fluidized bed for the next incineration step.

Exhaust gas generated in the combustion process is guided into the cyclone 30 from an exhaust gas inlet 30a. In the cyclone 30, solid particles are removed from the exhaust gas by a centrifugal separation mechanism (not shown), and the removed solid particles are collected as purified soil 33 in a solid particle collection unit 31. On the other hand, the exhaust gas from which the solid particles have been removed is sent to the secondary heating chamber 40. In the secondary heating chamber 40, the exhaust gas is heated to 1000 ° C. or more, preferably 1 ° C., by the afterburner 41.
Heated above 200 ° C. Thereby, the hardly decomposable organic substances such as dioxin contained in the exhaust gas are completely oxidatively decomposed.

The high-temperature exhaust gas heated in the secondary heating chamber 40 is further guided to a boiler 50. In the boiler 50, the exhaust gas is used as a heat source, and heats the boiler water 51 to generate steam 52. The steam 52 is sent to the power generator 60 and used for power generation. The outside air 53 sucked into the boiler 50 by the blower 54 is heated and sent to the lower air chamber 25 of the fluidized bed incinerator 20. With the above configuration, it is possible to efficiently reuse the energy used for incineration of the contaminated soils 12 and heating of the exhaust gas. The exhaust gas that has passed through the boiler 50 is further purified by a gas cleaning device 58, sucked by an exhaust gas suction blower 55, and released into the atmosphere as a clean gas 57 from a chimney 56.

[0016]

According to the present invention configured as described above,
The fuel required for incineration of contaminated soils and treatment of hardly decomposable pollutants can be greatly reduced. Furthermore, the energy used for the incineration of contaminated soils and the treatment of hardly decomposable pollutants such as dioxin can be separately and effectively used.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Incineration purification apparatus 12 Contaminated soils 14 High calorie waste 20 Fluidized bed incinerator 40 Secondary heating device 50 Boiler 60 Power generation device

Claims (4)

[Claims] 1. A method for incineration and purification of contaminated soils, comprising adding high calorie waste to the contaminated soils and incinerating them. 2. The exhaust gas generated by the incineration is further heated to completely decompose the hardly decomposable pollutants in the exhaust gas, and the heated exhaust gas is used as a separate heat source. The incineration purification method described. 3. The incineration purification method according to claim 2, wherein said contaminated soil is incinerated at 950 ° C. or lower, and said exhaust gas is heated to 1000 ° C. or higher. 4. An incinerator for adding high-calorie waste to contaminated soil for incineration, and heating the exhaust gas generated from the incinerator to completely decompose the hardly decomposable pollutants contained in the exhaust gas. An apparatus for incineration and purification of contaminated soils, comprising: an apparatus; and a heat engine that uses the exhaust gas heated by the exhaust gas heating apparatus as a heat source.