JP2001173932A - Method and apparatus for refining soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely and securely process wastes and incinerated ones thereof or radioactive wastes, and store them permanently, and further harden the soil. SOLUTION: A plasma torch for injecting plasma jet is inserted into an elongated hole formed in the soil, and hereby the soil around the elongated hole is heated and melted into stones due to its change to glass. The plasma torch is gradually moved in the elongated hole from a lower portion to an upper portion, and if a position on the soil to be melted is moved continuously from a lower to an upper portion, then the soil is made glassy, and elongated up and down into a column shape. When harmful gas is produced following the processing, the gas is collected and purified. For example, an opening of the elongated hole into which the plasma torch is put and the surrounding of the torch are surrounded with a hood, which hood then serves to collect the gas and feeds it to a gas purifying apparatus.

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 modifying soil by heating and melting the soil, vitrifying it, and turning it into rock.

[0002]

2. Description of the Related Art It is widely practiced to dispose of industrial waste and household waste by incineration. These wastes and their incinerated materials are used directly for landfill, collected in the mountains and piled up, or buried in the ground. In the case of radioactive waste, they are sealed in sturdy containers and stored in warehouses or underground.

In order to harden soft ground or to carry out foundation work for a high-rise building, struts such as concrete piles are deeply driven into the soil, and a hardening agent is mixed into the soil.

[0004]

SUMMARY OF THE INVENTION Wastes and incinerated materials,
Alternatively, radioactive waste materials and the like may leak out if the storage state after the treatment is poor. Therefore, there is a demand for a reliable storage method, but an appropriate method for storing them for a long period of time, preferably permanently, has not been obtained.
In addition, the costs associated with storing these are enormous.

[0005] Also, the use of a hardening agent to harden the soft ground has a great effect on the groundwater system and the environment since it changes the soil quality. Casting a concrete pile or the like poses a problem that the construction is large-scale and the cost is enormous.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a method for modifying soil that can safely and securely treat waste, incinerated material, radioactive waste, and the like and permanently store the waste. The primary purpose is to provide. It is a second object of the present invention to provide a soil reforming apparatus directly used for carrying out this method.

[0007]

According to the present invention, a first object is to insert a plasma torch for injecting a plasma jet into a long hole formed in soil, heat and melt the soil around the long hole, and vitrify the rock. And a soil reforming method characterized in that

[0008] By gradually moving the plasma torch from the lower part to the upper part in the long hole, and continuously moving the melting position from the lower part to the upper part, the soil can be vitrified vertically to form a column. In this case, by forming a large number of columnar portions hardened by vitrification, it is suitable for strengthening the ground.

When the soil contains wastes, it is conceivable that harmful gas is generated during the treatment. In this case, the gas is collected and purified. For example, the opening of the long hole in which the plasma torch is inserted and its surroundings are surrounded by a hood, and gas can be collected by the hood and guided to a gas purification device. In this case, it is preferable to spray a purifying liquid such as water into the hood to capture ash or carbon contained in the gas.

A second object is to provide a plasma torch, which is variably inserted into a long hole extending into the soil and emits a plasma jet, and a gas which the opening of the soil surface of the long hole covers and the periphery thereof and which the plasma torch emits. And a hood that captures gas generated by melting of the soil, a gas purification device that purifies the gas captured by the hood, and a cleaning liquid injector that sprays a cleaning liquid into the hood. Reformer.

[0011]

FIG. 1 is a diagram showing the use of an embodiment of the present invention, FIG. 2 is a conceptual diagram of an apparatus used here, FIG. 3 is a sectional view showing the structure of a hood, and FIG. FIG. 5 is a diagram showing an example of a processing method by this apparatus.

In FIGS. 1 to 3, reference numeral 10 denotes a hood. The hood 10 is made of a steel plate or the like in a substantially inverted bowl shape and has a horizontal partition wall 12 therein (FIGS. 2 and 3). The hood 10 is installed on the surface of the soil 14 so as to cover the opening of the long hole 16 provided in the soil 14 and its periphery. That is, FIG.
The hood 10 is fixed to an anchor 18 driven from the surface of the soil 14 by a mooring wire 20 as shown in FIG.

A guide pipe 22 vertically penetrating the center is fixed to the hood 10. This guide pipe 22
The upper end of the guide pipe 24 inserted from above into the long hole 16 of the soil 14 is guided by the taper of the guide pipe 22 so that the center axes of the guide pipes 22 and 24 are aligned. Done. That is, the hood 10 is hung by a crane or the like, and the tapered portion of the guide pipe 22 is aligned with the guide pipe 24 on the soil 14 side so that the hood 1
0 is put down on the soil 14 and fixed to the anchor 18. The guide pipe 24 is formed with a gas passage 26 that opens into the hood 10 (FIG. 3).

Reference numeral 28 denotes a plasma torch,
And inserted into the guide pipes 22 and 24 from above
6 is deeply entered. The plasma torch 26 has a smaller diameter than the guide pipes 22 and 24, and a sufficient gap is formed between the two to allow the gas to be described later to pass.

The plasma torch 28 can be configured, for example, as shown in FIG. In FIG. 4, reference numeral 30 denotes a center electrode, and 32 denotes a nozzle electrode surrounding the center electrode 30.
A shield cap 34 surrounds the nozzle electrode 32.
The electrodes 32 and 34 are supplied with cooling water from a cooling water pump 36 and are constantly cooled. This cooling water is cooled and circulates through the heat exchanger 38.

A plasma working gas is supplied between the center electrode 30 and the nozzle electrode 32 from a plasma working gas supply means 40. As the plasma working gas, an argon gas, a neon gas, an oxygen gas, a hydrogen gas, a helium gas, air, a mixed gas thereof, or the like is used. Here, air or a mixed gas mainly composed of air is used from the viewpoint of economy. Nozzle electrode 32 and shield cap 34
Is supplied with a shielding gas. Here, air is used as the shielding gas from the viewpoint of economy.
The shielding gas is supplied from the shielding gas supply means 42.

A high DC voltage supplied from a controller 44 is applied between the center electrode 30 and the nozzle electrode 32. Here, the center electrode 30 is connected to the negative electrode (−electrode), and the nozzle electrode 32 is connected to the anode (+ electrode). The controller 44 is supplied with power from a power supply 46. This power supply 4
6 drives a generator 50 with a diesel engine 48,
A transformer (transformer) 5
2 and converts it to a predetermined voltage.
4.

When the plasma torch 28 is used, a plasma arc is generated when the plasma working gas passes through the gap between the center electrode 30 and the nozzle electrode 32. The plasma arc is ejected from the nozzle of the nozzle electrode 32, and the diameter of the plasma arc is reduced to a small value due to the pinch effect caused by cooling the outside of the plasma arc with the shielding gas. 20,000 ° C)
As a result, the degree of plasma conversion (ionization) increases. Therefore, the plasma jet 54 is jetted as an ultra-high temperature plasma jet.
The plasma jet 54 has about 7,00
It becomes 0 ° C and about 4,000 ° C near the tip. The high-temperature plasma jet 54, together with the guide pipe 24 inserted deep into the long hole 16, hits and melts the surrounding soil.

The plasma jet 54 is applied to the soil 14
Is heated to an extremely high temperature, it is considered that the gas generated by the heating is separated even when the soil 14 contains waste or its incineration or radioactive waste. For example, nitrogen oxides (NO _x ) are decomposed into nitrogen gas (N ₂ ) and oxygen gas (O ₂ ), and carbon oxides (CO, CO _2, etc.) are similarly decomposed into carbon (C) and oxygen gas (O ₂ ). It is thought that it is modified into such. It is considered that ammonia gas (NH ₃ ), dioxin, and the like are similarly decomposed and made harmless.

The thus constructed plasma torch 28
Is inserted into the guide pipe 22 from above, and is lowered in the elongated hole 16. And a predetermined position, for example, the tip is a long hole 16
Is suspended and held so as to be located near the bottom of the vehicle. In this state, the space between the plasma torch 28 and the guide pipe 22 is sealed by the seal member 56 (FIG. 3). Cables such as a power cable and a shield gas cable connected to the plasma torch 28 are supplied from a cable car 58 (FIG. 1), and power and shield gas are supplied from a power / controller car 60 (FIG. 1) through these cables. And plasma working gas and cooling water are sent. In FIG. 1, reference numeral 61 denotes a tool wheel for carrying tools.

An appropriate number of exhaust pipes 62 (FIGS. 1 and 3) are inserted into the surface of the soil 14 surrounded by the hood 10 so that gas, water vapor, and the like generated when the soil 14 is melted by the plasma jet 54 can be removed. It is better to lead into 10. That is, the exhaust pipe 62 is inserted into the ground, for example, in parallel with the guide pipe 24 inserted into the long hole 16, and a portion in contact with the soil melted by the plasma torch 28 is melted together with the soil, and is generated in the melted soil. A part of the generated gas is guided by the exhaust pipe 62 and enters the hood 10. A part of the gas (shield gas or plasma working gas) emitted from the plasma torch 28 rises in the gap between the plasma torch 28 and the long hole 16 and enters the hood 10 through the guide pipe 24.

Gas, water vapor and the like flowing into the hood 10 enter the upper chamber 66 through the opening 64 (FIGS. 2 and 3) of the partition wall 12 of the hood 10. Water as a cleaning liquid is sprayed into the upper chamber 66 by a sprayer 68. This water contacts gas and water vapor in the hood 10 to capture and purify ash, carbon, water vapor, and the like contained in the gas and to cool the gas. In FIG. 2, reference numeral 69 denotes a cleaning water supply pump.

A part of the washing water flows out of the hood 10 through a small hole 70 provided in the upper chamber 66, and the lower chamber 7 of the hood 10
2 and flows down along the outer wall of the lower chamber 72 to cool the lower chamber 72 and
Into the water receiver 74 provided on the lower edge of the outer periphery of the water. The water receiver 74 communicates with the lower chamber 72 of the hood 10 through a small hole 76 (FIGS. 1 and 3), so that washing water accumulated on the surface of the soil 14 in the hood 10 enters the water receiver 74. . The liquid (cleaning water) stored in the water receiver 74 is sucked by the drainage device 78 (FIG. 2) and purified there.

The gas entering the upper chamber 66 of the hood 10 is guided to a gas purifier 82 by a pipe 80, where it is purified. That is, the gas generated when the plasma jet 54 melts the soil 14 enters the gas purification device 82 after generated particles such as ash and water-soluble substances are removed by washing water sprayed by the atomizer 68. It is purified by an electric dust collector and a harmful gas remover, and is discharged to the atmosphere. The hood 10 is provided with a pressure sensor 84 (FIG. 3).
If the internal pressure becomes excessive, a warning may be issued or the operation of the plasma torch 28 may be stopped.

Next, an example of soil modification will be described with reference to FIG. The guide pipe 2 is inserted into the long hole 16 formed in the soil 14.
Insert 4. The plasma torch 28 is put in the guide pipe 24 and the plasma torch 28 is placed near the bottom of the slot 16.
Position the lower edge of. Then, when the plasma jet 54 is emitted from the plasma torch 28, the surrounding guide pipe 24 and the soil 14 outside thereof are melted (FIG. 5A). After the melting portion 86 is generated, if the plasma torch 28 is gradually raised while the plasma jet 54 is being emitted, the melting portion 86 of the guide pipe 24 and the soil 14 can be formed.
Moves upward with the rise of the plasma torch 28.

The melting portion 86 is cooled from the bottom portion remote from the plasma torch 28, solidifies, vitrifies and turns into a rock (FIG. 5B). Numeral 88 indicates this rocked portion. If the plasma torch 28 is further raised, the melting portion 8
As 6 rises, the petrified portion 88 grows upward. Finally, if the injection of the plasma jet 54 by the plasma torch 28 is stopped, the entire molten portion 86 is solidified, and a columnar petrified portion 88 is completed.

By forming a large number of the columnar petrified portions 88 in the soil 14, the ground can be hardened and stabilized. Further, since the petrified portion 88 is extremely hard and glassy, the liquid does not exude and can be stabilized for a long time (permanently).

[0028]

According to the first aspect of the present invention, as described above, a plasma torch is inserted into a long hole formed in soil, the soil is melted by a plasma jet, and the soil is vitrified and turned into rock. Converting materials, incinerated materials, radioactive waste, etc. into hard and stable rocks and turning them into safe materials,
It can be suitable for permanent storage. In this case, the plasma jet can simultaneously decompose and detoxify various harmful gases generated when the soil is melted, so that there is no possibility that a new problem due to the gas will occur.

According to the second aspect of the invention, the soil can be continuously rocked in a columnar form, and the soil can be used for improvement of soft ground and foundation work for buildings. When waste is contained in the soil, the gas generated by melting by the plasma jet is collected in a hood and guided to a gas purifier to purify the gas, thereby further reducing the adverse effect on the environment. .

According to the fourth aspect of the present invention, there is provided a soil improvement apparatus used directly for carrying out this method.

[Brief description of the drawings]

FIG. 1 is a diagram showing a usage state of one embodiment.

FIG. 2 is a conceptual diagram of the apparatus.

FIG. 3 is a sectional view showing the structure of the hood.

FIG. 4 is a diagram showing a structure of a plasma torch.

FIG. 5 shows an example of a processing method.

[Explanation of symbols]

 Reference Signs List 10 hood 14 soil 16 long hole 28 plasma torch 68 cleaning liquid sprayer 82 gas purifier 86 melting part 88 petrification part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F23G 5/00 115 F23J 15/00 C F23J 15/02

Claims (4)

[Claims] 1. A soil reforming method comprising: inserting a plasma torch for injecting a plasma jet into a long hole formed in soil; heating and melting the soil around the long hole; . 2. Inserting a plasma torch into a long hole formed in the soil, heating and melting the soil around the long hole while pulling up the plasma torch, and moving the soil around the long hole from the bottom to the top of the long hole. The soil reforming method according to claim 1, wherein the soil is continuously vitrified. 3. The soil reforming method according to claim 1, wherein the soil contains wastes and gas generated by melting of the soil is collected and purified by a hood covering the surface of the soil. 4. A plasma torch, which is variably inserted into an elongated hole extending into the soil and emits a plasma jet, and an opening on the soil surface of the elongated hole and its surroundings, and a gas and a melt of the soil emitted by the plasma torch. A soil reforming device comprising: a hood for capturing gas generated with the hood; a gas purification device for purifying the gas captured by the hood; and a cleaning liquid injector for injecting a cleaning liquid into the hood.