JP2000061443A - Device for separating and removing harmful material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently separate and remove various harmful materials from contaminated soil, etc. SOLUTION: This device 1 for separating and removing a harmful material is composed of an airtight storage 3 for the contaminated soil 2 as an object contg. the harmful material, an exhaust pipe 4 communicating with the airtight storage 3, a vacuum pump 6 connected to the exhaust pipe 4 through a gas-liq. separation tank 5 and a collecting device 7 connected to the downstream side of the vacuum pump 6. The gas in the storage 3 is evacuated by the vacuum pump 6 through the exhaust pipe 4 to lower the gas pressure in the storage 3. Consequently, the harmful material in the contaminated soil 2 is volatilized by the b.p. depression action of the harmful material due to the pressure lowering in the storage 3, and further the volatilized harmful material is discharged outside the storage 3.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an apparatus for separating and removing various harmful substances such as oil and organic chlorine compounds contained in contaminated soil, industrial waste, sludge and the like from the contaminated soil and the like.

[0002]

2. Description of the Related Art Fuel oil and machine oil are sometimes mixed with excavated soil and carried out when foundation work is performed on a site of a factory.
If such oil-contaminated soil is left as it is, the oil content mixed in the soil volatilizes and diffuses to the surroundings, hindering the lives of neighboring residents, and when it is released from soil particles by rainwater, groundwater, etc. It can also cause contamination of water quality. Therefore, for such oil-contaminated soil, it is necessary to remove the oil content by incineration, for example, to prevent its diffusion into the environment.

Further, the soil at the site of the factory may be contaminated with organic chlorine compounds such as trichlorethylene and tetrachloroethylene, and sufficient measures must be taken to prevent the diffusion of such pollutants.

[0004]

However, it goes without saying that when incinerating contaminated soil, sludge, industrial waste, etc., considerable energy is required during incineration and soil characteristics change. However, there has been a problem that harmful by-products such as dioxins may be generated depending on contaminants or incineration temperature.

On the other hand, there is also a method in which quick lime is added to contaminated soil or the like to react with the contained water, and the pollutants are volatilized by the heat generated at that time, but in addition to the problem that the soil characteristics change, heat generation However, it has been difficult to efficiently remove the harmful substances by volatilization.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a device for separating and removing harmful substances from which various harmful substances can be efficiently separated and removed from contaminated soil or the like. And

[0007]

In order to achieve the above object, the device for separating and removing harmful substances according to the present invention has an airtightness in which an object containing a harmful substance is accommodated as described in claim 1. A container, an exhaust pipe communicated with an airtight space in the container, and a gas in the container is drawn out through the exhaust pipe to reduce the atmospheric pressure to volatilize the harmful substance from the inside of the object. A vacuum pump that discharges the volatilized harmful substance to the outside of the containing body, and a collecting device that is connected to the upstream side or the downstream side of the vacuum pump and collects the harmful substance discharged from the containing body Is.

Further, the harmful substance separating / removing apparatus according to the present invention has a stirring means installed in the container.

The toxic substance separating / removing apparatus according to the present invention includes a heating means for heating the inside of the container.

In the hazardous substance separating / removing apparatus according to the present invention, first, an object containing a hazardous substance is put into an airtight container and sealed. Next, the air in the housing is reduced by a vacuum pump through the exhaust pipe communicating with the airtight space in the airtight housing to reduce the air pressure.

In this way, the boiling point of the harmful substance is lowered in the container due to the decrease of the air pressure, and the harmful substance in the object is volatilized. Therefore, the harmful substance is discharged to the outside of the container and further collected by the collecting device. to recover. Even after the air is removed, the gas in the airtight space, that is, the vaporized harmful substance is removed to maintain the reduced pressure state, so that the harmful substance in the object is continuously vaporized.

[0012] As the object containing the harmful substance,
Although it is mainly contaminated soil, it also includes slag, incineration ash, sludge, concrete waste, plastic waste, waste wood, etc.

As the harmful substances, oils, trichloroethane, trichloroethylene, tetrachloroethylene, P
Includes organochlorine compounds such as CB, and aromatic hydrocarbons such as benzene, toluene, naphthalene, and phenol, as well as all substances that have a boiling point below room temperature under reduced pressure, especially at a vacuum of several mmHg or less. To be done. Therefore, heavy metals such as mercury are also included in the harmful substances in the present invention.

It is desirable that the air pressure in the airtight space is set to be equal to or lower than the vapor pressure of harmful substances at the temperature in the space. If the atmospheric pressure is lowered to this extent, the harmful substances contained in the target object will immediately volatilize. The vapor pressure of the harmful substance does not necessarily have to be lower than the vapor pressure, and although the efficiency is slightly lowered, a considerable volatilization action can be expected if the pressure is close to the vapor pressure.

Here, when the stirring means is installed in the container, the stirring means stirs the object contained in the container. By doing so, it is possible to promote the above-mentioned volatilization action and to evenly volatilize the harmful substances mixed in the object.

When a heating means for heating the inside of the container is provided, the inside of the container is heated by the heating means. By doing so, the vapor pressure of the harmful substance increases due to the temperature rise in the container, and it becomes possible to volatilize and recover the harmful substance without raising the vacuum degree too much.

The configuration of the heating means is arbitrary, and for example, it is heated by irradiating electromagnetic waves, the surplus heat of a refuse incinerator or the like is fed into the airtight space in the form of warm air, and the heat generation of electric heating means or the like. It is possible to install the body in the container or pass warm water through the container.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a device for separating and removing harmful substances according to the present invention will be described below with reference to the accompanying drawings. It should be noted that parts and the like which are substantially the same as those of the conventional technique are designated by the same reference numerals and the description thereof will be omitted.

FIG. 1 is an overall view showing a device for separating and removing harmful substances according to this embodiment. As you can see in the figure,
The hazardous substance separation / removal device 1 according to the present embodiment includes heavy oil,
Light oil, kerosene, oil such as gasoline, trichlorethylene,
An airtight container 3 in which a polluted soil 2 containing a harmful substance such as an organic chlorine compound such as tetrachloroethylene is contained, an exhaust pipe 4 communicating with the airtight space in the container, and an exhaust pipe It is composed of a vacuum pump 6 connected via a gas-liquid separation tank 5 and a collection device 7 connected to the downstream side of the vacuum pump.
The gas in the container 3 is drawn out through the air to lower the atmospheric pressure in the container 3, and the harmful substance in the polluted soil 2 is volatilized by the boiling point lowering action of the harmful substance accompanying the pressure decrease in the container 3, Further, the volatilized harmful substance is discharged to the outside of the container 3.

The airtight container 3 may be made of any material. For example, if it is made of a steel container,
It is possible to prevent the polluted soil 2 which is the object from being affected by atmospheric pressure and obstructing volatilization.

A barometer 10 is attached to the gas-liquid separation tank 5 so that the air pressure inside the communicating container 3 can be measured, and a drain valve 12 is provided near the bottom of the tank. By opening the drain valve, it is possible to remove harmful substances accumulated in the gas-liquid separation tank 5 and water evaporated from the contaminated soil 2.

The collecting device 7 is composed of an activated carbon adsorption tower, adsorbs volatile components, which are harmful substances, from the gas discharged from the vacuum pump 6, and exhausts the air from which the volatile components have been removed. It is designed to release from 15. As the adsorbent to be filled in the collection device 7, other than activated carbon,
It may be appropriately selected from silica / alumina-based adsorbents, synthetic adsorbents such as molecular sieving carbon, zeolite, and acid clay also called activated clay, depending on the adsorption property of harmful substances.

On the other hand, an agitating mechanism 22 which is rotatably driven by a drive motor 21 is attached to the container 3, and the drive motor 21 and the agitating mechanism 22 raise or lower the agitating mechanism 22 by the drive motor 21. By rotating, the stirring blade 23 acts as a stirring means for stirring the contaminated soil 2.

A water pipe 24 is provided in the wall cross section of the container 3.
And a boiler 25 is connected to the water pipe. That is, the water pipe 24 and the boiler 25 heat the hot water supplied from the boiler 25 through the water pipe 24 to heat the inside of the container 3, and the cold water whose temperature has been lowered by heating is circulated to the boiler 25 again to be housed. It acts as a heating means for heating the inside of the body 3.

On the upstream side of the gas-liquid separation tank 5, a liquefying device 26 and a cooling device 27 for supplying cold water to the liquefying device and cooling the hot water warmed by heat exchange and circulating it to the liquefying device 26 again. Liquefaction device 2
6 and the cooling device 27 act as a liquefying means for liquefying the volatile components in the exhaust pipe 4.

In order to separate and remove harmful substances from the contaminated soil 2 by using the separation / removal device 1, first, the charging port 2 of the container 3
The polluted soil 2 is charged from 8 and sealed, and then the vacuum pump 6 is operated to draw out the air in the container 3 to lower the air pressure in the container.

As for the degree of lowering the air pressure, it is desirable to operate the vacuum pump 6 so that the air pressure in the container 3 becomes equal to or lower than the vapor pressure of harmful substances at the temperature in the container. Specifically, when the harmful substance is kerosene, its vapor pressure curve is as shown in FIG. 2, so that if the temperature is about 25 ° C., it may be lowered to about 60 mmHg or less. For reference, the vapor pressure curves of water and ethyl alcohol are also drawn in the figure, and it can be seen from the figure that the volatile oil content can be recovered prior to the steam.

When the air pressure in the container 3 is lowered in this way, the boiling point of the harmful substance drops due to the decrease in the air pressure in the container, and the harmful substance in the contaminated soil 2 is immediately volatilized. At 6, suction is performed from the container 3. Then, the liquefied component in the liquefaction device 26 is collected in the gas-liquid separation tank 5, the remaining volatile components are adsorbed and collected in the collection device 7, and the purified air is discharged from the exhaust port 15. On the other hand, the solution containing the harmful substance accumulated in the gas-liquid separation tank 5 is sent to a waste water purification facility or a waste treatment facility for appropriate treatment.

Even after the air is evacuated, the volatile components in the container 3 are evacuated by the vacuum pump 6 to maintain the reduced pressure state, so that the harmful substances in the contaminated soil 2 are continuously volatilized.

The time for operating the vacuum pump 6 is appropriately adjusted depending on how much harmful substances are desired to be removed. Further, after the pressure is once lowered to a predetermined atmospheric pressure, it is sufficient to intermittently operate the vacuum pump 6 or operate with the output weakened so that the pressure is reduced by an amount corresponding to the pressure increase due to the harmful substances volatilized in the container 3. .

While the vacuum pump 6 is performing the volatilization suction, the stirring mechanism 22 is appropriately driven by the drive motor 21 to stir the contaminated soil 2, and the boiler 25 is operated to let the hot water pass through the container 3. The contaminated soil 2 is heated by supplying it to the water pipe 24.

In this way, the volatilization action of the harmful substances from the polluted soil 2 is promoted, and the uniform volatilization from the polluted soil 2 can be expected.

When the harmful substances in the contaminated soil 2 have been separated and removed to a desired degree, the vacuum pump 6 is stopped and the treated soil is taken out from the discharge port 29. The treated soil may be used as an embankment material, for example.

By installing a detection sensor near the exhaust port 15 of the collection device 7, the content of volatile components from the exhaust port 15 is monitored, and when the measured value exceeds a certain value, the collection device 7 It is preferable to determine that the adsorption capacity of the activated carbon in 7 has decreased and recover the adsorption ability by heating the activated carbon in the collection device 7 or the like.

As described above, according to the hazardous substance separation / removal device of this embodiment, the harmful substance contained in the polluted soil 2 is immediately volatilized due to the drop in the boiling point of the hazardous substance due to the decrease in atmospheric pressure. 3 can be discharged to the outside.

Therefore, it becomes possible to separate and remove harmful substances from the contaminated soil 2 in a short time without spending a large amount of incineration energy and without generating harmful by-products such as dioxins during incineration. Moreover, the treated soil was not treated with quicklime or incineration, so
There is no change in soil properties and no need for dehydration as it has not been water treated. Therefore, the treated soil can be diverted to the embankment material as it is.

Further, according to the harmful substance separation / removal apparatus 1 of this embodiment, the vacuum pump 6 is operated so that the atmospheric pressure in the container 3 becomes equal to or lower than the vapor pressure of the harmful substance at the temperature in the container. Therefore, the harmful substance contained in the polluted soil 2 is immediately volatilized, and the harmful substance content in the polluted soil 2 can be reduced in a short time.

Further, according to the hazardous substance separating / removing apparatus 1 of the present embodiment, the contaminated soil 2 is agitated in the container 3 by the agitating mechanism 22, so that the volatilizing action of the hazardous substance due to the lowering of the boiling point can be achieved. While being promoted, it is possible to evenly volatilize harmful substances mixed in the contaminated soil 2.

Further, according to the hazardous substance separating / removing apparatus 1 according to the present embodiment, the warm water from the boiler 25 is stored in the container 3.
Since the contaminated soil 2 is heated by passing it through the water passage pipe 24 inside, the vapor pressure of the harmful substance increases due to the temperature rise in the container 3, and the harmful substance is volatilized and recovered without raising the vacuum degree too much. It becomes possible to do. In addition, a synergistic effect that the inside of the container 3 can be uniformly heated by the stirring mechanism 22 described above can be expected.

In the present embodiment, the object for separating and removing harmful substances is the contaminated soil 2. However, the object of the present invention is not limited to the contaminated soil 2, and instead of this, slag or incineration is used. The object may be ash, sludge, concrete waste material, plastic waste material, waste wood, or the like.

Further, in the present embodiment, the volatile matter, which is a harmful substance, is collected by adsorption of activated carbon, but instead of this, for example, the volatile matter may be collected in the form of being dissolved in a solvent. .

Further, in the present embodiment, the liquefying device 26 and the gas-liquid separation tank 5 are installed between the container 3 and the vacuum pump 6 to collect by cooling and liquefying, but this is omitted. The harmful substances may be collected only by the collecting device 7.

Further, in the present embodiment, the gas-liquid separation tank 5, the vacuum pump 6, and the collecting device 7 are connected to the container 3 in this order. First, in the gas-liquid separation tank 5, the vacuum pump 6 is so-called dry. If it is of a type, this may be omitted, or the order of the vacuum pump 6 and the collection device 7 may be exchanged.

Further, in this embodiment, the drive motor 21 and the stirring mechanism 22, which are stirring means, and the water pipe 24 and the boiler 25, which are heating means, are installed for the purpose of accelerating the volatilization action, but only the vacuum pump 6 is provided. Either or both of these may be omitted as long as the harmful substances can be efficiently collected in.

Further, in the present embodiment, the water pipe 24 is embedded only in the wall cross section of the container 3, but if the inside of the container 3 can be heated, how can the water pipe 24 be formed. It may be embedded. For example, if it is embedded also in the shaft portion of the stirring mechanism 22 and the stirring blades 23, the heating efficiency can be improved.

Although not particularly mentioned in the present embodiment, when the contaminated soil 2 containing a harmful substance is sealed in the container 3, a predetermined vaporization accelerator may be added to the contaminated soil. Good.

In this way, since the harmful substance is easily volatilized in the container 3 by the action of the vaporization accelerator, even if the harmful substance is not vaporized even when the depressurizing operation is performed, the harmful substance is promptly removed. It becomes possible to volatilize and separate and remove from the contaminated soil 2. Incidentally, such a vaporization accelerator,
As shown in FIG. 3, even after sealing, it may be added to the contaminated soil 2 through the injection port 30 that is connected and communicated with the inside of the container 3.

As a specific example, cyanide which is volatilized as a cyanide gas by adding an acidic solution, and arsenic and hydrochloric acid which is volatilized as an arsine gas by adding an oxidizing solution and an oxidizing agent to increase the redox potential are added. In the case of cyanide, the acidic solution serves as a vaporization promoter, in the case of arsenic, the acidic solution and the oxidizing agent serve as a vaporization promoter, and in the case of mercury, hydrochloric acid is a vaporization promoter. Becomes In addition, if it is a harmful substance such as oil targeted in this embodiment,
It is possible to smoothly vaporize only by the depressurization operation without adding the vaporization accelerator, but it goes without saying that if the vaporization accelerator is added in addition to the depressurization operation, the efficiency of removing harmful substances can be significantly increased.

[0049]

As described above, according to the apparatus for separating and removing harmful substances of the present invention according to claim 1, the boiling point of the harmful substances is lowered by vacuum suction, and the harmful substances contained in the object are immediately volatilized. Can be discharged to the outside of the container. Therefore, it becomes possible to separate and remove the harmful substances from the target in a short time without spending a large amount of incineration energy and without generating harmful by-products such as dioxins during the incineration. Moreover, since the treated soil has not been treated with quick lime or incinerated, the soil characteristics have not changed, and since it has not been treated with water, there is no need for dehydration. Therefore, the treated soil can be diverted to the embankment material as it is.

Further, according to the apparatus for separating and removing harmful substances of the present invention according to claim 2, the volatilization action by vacuum suction is promoted and the harmful substances mixed in the object are uniformly vaporized. There is also an effect that it becomes possible.

Further, according to the apparatus for separating and removing harmful substances of the present invention according to claim 3, the vapor pressure of the harmful substances increases due to the temperature rise in the containing body, and the harmful substances are volatilized without raising the vacuum degree too much. There is also an effect that it becomes possible to collect.

[0052]

[Brief description of drawings]

FIG. 1 is an overall view of a device for separating and removing harmful substances according to the present embodiment.

FIG. 2 is a graph showing the operation of the harmful substance separation / removal device according to the present embodiment.

FIG. 3 is an overall view of a device for separating and removing harmful substances according to a modification.

[Explanation of symbols]

1 Separation and removal device 2 Contaminated soil (target) 3 housing 4 exhaust pipe 5 Gas-liquid separation tank 6 vacuum pump 7 Collection equipment 21 Drive motor (stirring means) 22 Stirring mechanism (stirring means) 24 Water pipe (heating means) 25 boiler (heating means)

Claims (3)

[Claims] 1. An airtight container for accommodating an object containing a harmful substance, an exhaust pipe communicating with an airtight space inside the container, and a gas in the container extracted through the exhaust pipe. A vacuum pump that volatilizes the harmful substance from the inside of the object by lowering the atmospheric pressure and discharges the volatilized harmful substance to the outside of the container, and the vacuum pump connected to the upstream side or the downstream side of the vacuum pump. A device for separating and removing harmful substances, comprising: a collecting device for collecting the harmful substances discharged from the body. 2. The separation / removal device according to claim 1, wherein stirring means is installed in the container. 3. The separation / removal device according to claim 1, further comprising heating means for heating the inside of the container.