JPH10192835A - Method and apparatus for treating soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dig on soil by a jet burner and to reduce running costs by a method in which when polluted soil is cleaned using a jet by a jet burner, the opening of a reaction kettle is mounted on soil to be treated, and jetted flame is applied to the soil. SOLUTION: A soil treatment apparatus has a burner 1 and a reaction kettle 2, the burner 1 is burned, and soil treatment is advanced is by the kettle 2 so that the soil is dug up by a jet, dried and crushed in the kettle 2, and discharged outside the kettle 2. In the dug-up soil, a solid content of a large diameter is classified by the first classifier 3, an unclassified solid content is classified by the next second classifier 4 into a residual solid content and a gasification component. The gasification component is cooled by the first condenser 5 to recover substances of higher boiling points such as heavy oil first, by the second condenser 6 to recover solvent components of lower boiling points and water, and finally the residual components are adsorbed by an adsorption apparatus 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for restoring contaminated soil to a clean state by using jet injection by a jet burner.

[0002]

2. Description of the Related Art In recent years, environmental problems have become particularly prominent among social problems, but improvement of soil contaminated with harmful substances is one of the biggest environmental problems.

In general, soil pollution refers to inorganic substances such as heavy metals, chlorine compounds such as trichloroethylene, trichloroethane and tetrachloroethylene, benzene, xylene,
It refers to a case where one or more kinds of aromatic compounds such as toluene and other various organic compounds are contained. In particular, in recent years, there has been a worldwide concern about the problem of contamination of organic compounds including chlorine-based compounds, and regulations have been strengthened legally. Soil contaminated with these must be promptly rehabilitated, but in practice it is difficult to perform this soil treatment in a simple and inexpensive treatment process. There must be.

[0004] Generally, soil decontamination can be performed by methods such as immobilization of contaminants, incineration, microbial treatment, solvent extraction, and thermal desorption. However, the factors required for soil decontamination are that no by-products are generated after treatment, that the treatment can be performed on the spot without moving the soil, that the equipment is small, that the treatment cost is low, that And low risk.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned various requirements for soil treatment. In order to solve the drawbacks, the present invention is directed to soil treatment using jet injection from a jet burner. An object of the present invention is to provide a soil treatment method and apparatus characterized by performing.

[0006] The jet injection referred to here is a flame generated from a combustor called a jet burner. Since the temperature is high and the speed is high, it can be used for drilling, pulverizing, drying, crushing and the like. Utilizing its features, jet burners were initially used for cutting stone at quarries and the like.

[0007] The jet burner generates jet injection by using a fuel such as gasoline, kerosene, or heavy oil and mixing it with air or oxygen and burning it in a combustion cylinder. The gas produced by the combustion is blown out of the burner through the nozzle. The combustion temperature in the combustion cylinder is usually 1200 ° C
To about 2700 ° C, and the velocity at the time of being ejected to the outside of the burner through the nozzle is 1000 to 1500 m /
Seconds. Jet injection is very fast,
When colliding with an object, the impact on the object is large and the heat transfer to the object is fast, so that the temperature of the object can be raised rapidly.

[0008] Jet burners having these characteristics are being considered for application in several applications. For example, JP-A-7-275897 proposes a method and an apparatus for treating oily waste using a jet burner.

A feature of the present invention is that a conventional jet burner puts a treated material into a reactor and performs the treatment, while a conventional jet burner is intended for a large-scale one such as environmental restoration of soil. On the other hand, it is possible to reduce the running cost by directly carrying out environmental restoration with a jet burner without any pretreatment of the soil and digging the soil with a jet burner.

[0010]

SUMMARY OF THE INVENTION The present invention provides a method and an apparatus for performing an environmental remediation treatment of contaminated soil using a jet burner as described above, and further provides a method and an apparatus for performing the method. The jet injection from the jet burner makes it possible to carry out the treatment efficiently by directly contacting the soil, and digging the soil by the jet injection reduces the running cost and the number of steps.

The term "contaminated soil" as used in the present invention refers to a soil containing an organic compound such as an inorganic substance, a chlorine compound, or an aromatic compound, particularly a soil containing a chlorine compound or an organic compound. However, the present invention is not limited to this. These may be industrially contaminated, such as those contained in factory effluent or factory exhaust, or they may be contaminated by domestic waste generated from ordinary life.

The concrete soil treatment will be described below. First, the jet spray of the jet burner is brought into contact with the contaminated soil. Jet injection is high-temperature, high-pressure combustion gas generated by complete combustion in the combustion chamber of a jet burner. The combustion gas is emitted from the nozzle as a jet jet and comes into contact with the soil. In a normal jet burner, this contact is performed in a closed kettle, but according to the present invention, at least one part of the reaction kettle is in an open state, and the jet jet and the soil come into contact through this part. . Due to this contact, the soil is brought to a high temperature state, and is excavated by receiving an external force by jet injection. In addition, the air or oxygen used for combustion is converted into combustion gas by a combustion reaction, and the soil scatters in the pot due to the gas pressure. As a result, the organic matter contained in the soil becomes hot and volatilizes. The volatilized organic matter is taken out of the kettle together with the pulverized soil by gas pressure, and after being taken out of the kettle, is collected by a collecting device connected thereto. The soil is separated and collected by a classifier such as a cyclone, but the number of these collectors and the classifier and the connection method are not particularly limited.

The present invention will be described below with reference to the drawings, but the present invention is not limited thereto. FIG. 1 schematically shows an overall view of the apparatus. The central part of the apparatus is composed of a burner 1 and a reactor 2. The burner 1 is a portion in which fuel burns together with air, oxygen, and the like, and the reactor 2 is a portion in which soil is scattered, crushed, and dried.

[0014] As described above, the soil treatment is promoted by the reaction kettle, so that the soil to be treated is dug out by jet injection, dried and crushed in the reaction kettle, and then discharged to the outside of the kettle. Will be issued. The released soil is recovered in a subsequent step. One example is described below, but the number of recovery stages and the set temperature are only examples, and the present invention is not limited to this.

The excavated soil first enters the first classifier 3. This first classifier comes with a temperature controller,
The temperature is set at 300 to 400 ° C., and at this portion, those having a large diameter among the solid contents are classified and taken out. Those not classified enter the next second classifier 4 where they are further classified into the remaining solids and vaporized components. The temperature of the second classifier is set at 300 to 400 ° C. as in the first classifier.

The vaporized component enters the next first condenser 5, where it is cooled by a cooler to about 100 to 200 ° C., and a substance having a high boiling point such as heavy oil is recovered first. In the subsequent second condenser 6, like the first condenser,
The mixture is cooled to about 30 ° C. by a cooler, and a solvent component and water having a low boiling point are recovered. Finally, the remaining components are adsorbed by the adsorber 7 to prevent release to the atmosphere. This adsorbent may be, for example, activated carbon.

As described above, according to the present invention, environmental restoration of contaminated soil can be easily performed in a wide range.

[0018]

Although the effects of the present invention are apparent as described above, the effects of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. is not.

Example 1 A soil treatment apparatus shown in FIG. 1 was used to treat soil preliminarily containing tetrachloroethylene. Mountain sand is used for soil, width 10m, depth 10m,
An artificial soil having a depth of 4 m was prepared and treated for 30 minutes.

In the jet burner used in this case, about 1500 ° C., about 8 kg / cm ² , about 1200 m /
This was done by a second jet jet. However, there is no particular limitation. Kerosene was used as fuel, and 60 liters were consumed. The reactor had a diameter of 1000 mm. Further, six drills having a diameter of 40 mm were used as auxiliary drilling devices inside the reactor, and the reactor was installed and operated near the open portion of the reactor as shown in FIG.
During the reaction, the temperature inside the kettle was about 150 ° C., and the temperature of the condenser for recovery was 100 ° C. for the first condenser and 30 ° C. for the second condenser.

As a result of the treatment, the soil is about 1000 m at the deepest part.
m, and about 1178 kg of soil was recovered.
As a result of measuring the amount of tetrachloroethylene on the soil before and after the treatment by the method shown in Notification No. 46 of the Environment Agency in 1991, the following values were obtained.

Before treatment: 8.9 mg / l After treatment: 0.005 mg / l Example 2 The same method as in Example 1 except that tetrachloroethylene was not previously contained in the same soil using the same apparatus as in Example 1. Soil treatment was carried out. As a result of the treatment, the amounts of the substances recovered by the respective recovery devices are as follows.

Recovered amount of the first classifier 881.4 kg Recovered amount of the second classifier 205.2 kg First condenser 0.1 kg Second condenser 204.5 kg

[0024]

As described above, the effects of the present invention are clear, and the main effects are summarized as follows.

1. Environmental remediation of contaminated soil can be treated on site.

2. By directly contacting the flame jet with the soil, the number of steps in the treatment is reduced, the cost can be reduced, and the apparatus can be simplified.

3. By excavating the soil by making the burner movable, it is possible to reduce costs and time, such as movement of the apparatus and human load, associated with the treatment.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a configuration of a soil treatment device of the present invention.

FIG. 2 is a state diagram of a soil and a reaction kettle before treatment.

FIG. 3 is a state diagram of a soil and a reaction kettle at the start of treatment.

FIG. 4 is a main view of a device attached to an auxiliary drilling hole.

FIG. 5 is a state diagram when a reaction kettle is dug into soil.

FIG. 6 is a diagram of a main part movable model by a motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Jet burner 2 Reactor 3 First classifier 4 Second classifier 5 First condenser 6 Second condenser 7 Adsorber 8 Drill for drilling 9 Motor

Claims (4)

[Claims] 1. A reaction vessel having an opening provided by holding a jet burner emitting a flaming flame at the center, a classifier connected from an arbitrary position on the upper part of the reaction vessel through a pipe, and further connected to the classifier through a pipe. A condenser, and an adsorber connected to the condenser through a tube, wherein the opening of the reaction vessel is placed on the contaminated soil to be treated, and the flame is effectively applied to the contaminated soil to be treated. Characterized equipment for treating contaminated soil. 2. The soil treatment apparatus according to claim 1, wherein the soil treatment apparatus has a structure in which treated soil is dug by jet injection. 3. The soil treatment apparatus according to claim 2, wherein the structure capable of digging the soil has an auxiliary device such as a drill for digging the soil as an aid of the jet burner. 4. A reaction vessel covering both sides and an upper part is placed on the contaminated soil, a flame radiated from a jet burner is applied to the contaminated soil, and the contaminated soil is crushed and heated in the reaction vessel. Then, a solid substance and a gas phase generated in the reactor are separated by a classifier, and a contaminant is recovered from the gas phase by a condenser and an adsorber.