JP2001269659A - Treatment method of soil contaminated with oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently separate and remove oily components from a soil contaminated with oil. SOLUTION: The soil contaminated with oily components are made fine grains by a fine grinning device 20 and after the oily components sticking to the surfaces of the soil particles of the soil contaminated with oil are separated from the soil particles, the particles are supplied to a liquid cyclone 41 where the oily components are removed. The soil particles of large grain sizes which are discharged from the lower discharge port of the liquid cyclone 4 and from which the oily components are removed, are classified by a classifying device, such as a vibration screen 43 or dehydrating vibration screen 44.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for efficiently separating oily components from soil contaminated with oily components.

[0002]

2. Description of the Related Art Crude oil adheres to and contaminates beach soil contaminated with crude oil spilled into the sea due to a marine accident and excavated soil carried out in connection with the excavation of a tunnel in the ground where crude oil exists. Processing is often difficult. Conventionally, such oil-contaminated soil has been accumulated in a treatment plant, and after condensing and solidifying oily components by chemical treatment or the like, it has been disposed of at a final disposal site.

[0003]

However, the above-mentioned treatment method has problems that the treatment is troublesome and the disposal amount of the treated soil is increased. Therefore, it is desired to establish a technology for removing oily components from such oil-contaminated soil, extracting gravel, sand, fine particles, and the like contained in the oil-contaminated soil for reuse.

The present invention has been made in view of the conventional problems, and efficiently separates and removes oily components from oil-contaminated soil, and further recycles the harmless soil particles from which the oily components have been separated. An object of the present invention is to provide a method for treating oil-contaminated soil that can be used.

[0005]

According to a first aspect of the present invention, there is provided a method for treating oil-contaminated soil, wherein the soil contaminated with an oily component is introduced into a treatment space, and water is added thereto while adding water. By applying the force of compression and rubbing between particles,
After the soil is refined, the soil is refined by a refiner that separates oily components attached to the surface of the soil particles from the soil particles, and then discharged from the refiner. The slurry is supplied to a liquid cyclone to remove the oil component.

According to a second aspect of the present invention, in the method for treating oil-contaminated soil, a classifying means is provided downstream of the hydrocyclone for classifying soil particles having a large particle diameter discharged from a lower discharge port of the hydrocyclone. Is classified.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a processing flow of an oil-contaminated soil treatment system according to an embodiment of the present invention. After separating the oily component adhering to the surface of the oil, the slurry discharged from the fine-granulating device 20 is classified by the classification means 40 to remove the gravels, sand, fine particles, etc. contained in the oil-contaminated soil. It can be extracted and reused. In FIG. 1, reference numeral 20 denotes a method of compressing and rubbing between soil particles of the oil-contaminated soil while adding water to the oil-contaminated soil input through the receiving hopper 11, thereby finely dividing the soil. A fine-granulating device which granulates and separates oily substances adhering to the surface of the above-mentioned soil particles from the above-mentioned soil particles and floats them in treated water. While storing, the slurry is classified
A liquid supply tank (hereinafter, referred to as a feed sump) for supplying the liquid cyclone 41 with the liquid cyclone 4.
1, a classifying device including a classifying device such as a vibrating screen 43, a dewatering vibrating screen 44, and the like, classifying means for classifying soil particles contained in the material supplied from the feed sump 30 into soil particles of various sizes; A water treatment section for purifying treated water containing oily components discharged from 40, and a water supply section 60 for supplying treated water to the granulating device 20 and the feed sump 30.

FIG. 2A is a view showing the configuration of the grain refiner 20, and FIG. 2B is a sectional view taken along line AA of FIG. The grain refiner 20 is attached to the inner peripheral surface along the axial direction, and is attached to the cylindrical rotary drum 1 having a plurality of outer blades 1W protruding in the center direction, and attached to the outer peripheral surface along the axial direction, A rotor 2 having a plurality of radially projecting inner blades 2W and eccentrically mounted inside the rotary drum 1;
The ring gear 3 provided on the outer periphery of the rotary drum 1 is
As a result, the rotating shaft 5 attached to the rotor 2 is
Respectively, thereby rotating the oil contaminated soil, which is the processing material charged into the material input port 7 of the grain refiner 20, in a direction opposite to each other, and exerting a compressive and sliding stress on the oil-contaminated soil. Separated into fine particles and refined, the finely-divided soil particles, by mainly applying the force of rubbing between the particles, to perform mutual polishing by friction between the particles, It is for separating foreign substances such as oily substances adhering to the surface of the soil particles. The magnitude of the stress acting on the processing material mainly depends on the distance between the rotating drum 1 and the rotor 2 (the eccentricity of the rotor 2) and the rotating drum 1
And the rotation speed of the rotor 2.

Next, a processing flow of the oil-contaminated soil will be described. First, the oil-contaminated soil put into the receiving hopper 11 is put into the material inlet 7 of the grain refiner 20. In the grain refiner 20, the treated water supplied from the water supply unit 60 is added to the oil-contaminated soil, and the agglomerated soil particles of the oil-contaminated soil are refined. The oily soil adhering to the surface of the soil particles is removed while floating in the treated water, and the oil-contaminated soil is moved downstream and discharged from the outlet 20a. At this time, solids such as large metals and contaminants mixed into the oil-contaminated soil are captured and removed by a capture net 20b of about 30 mm provided at the outlet 20a, and are removed. 30mm
A slurry containing the following soil particles is sent to the feed sump 30. Among the slurry-like oil-contaminated soil stored in the feed sump 30, the slurry containing relatively large-diameter particles stored at the bottom is fed to the feed pump 30P.
Is sent to the hydrocyclone 41 of the classification means 40 and classified. The liquid cyclone 41 is a device that injects liquid containing various-sized particles at a high speed onto the inner wall of a cylindrical main body to separate small-particles having a small particle diameter contained in the liquid. When moving downward along the inner wall of the main body while forming a vortex called a primary rotating flow, the pressure in the center of the main body decreases, and the liquid forms a vortex called a secondary rotating flow while the primary rotating flow moves. This utilizes the phenomenon that the body rises from the inside. That is, the granular material having a small particle diameter contained in the slurry introduced into the hydrocyclone 41 is carried by the secondary rotation flow and moves toward the upper part of the main body, and passes through a rising pipe (not shown) above the hydrocyclone. Is discharged. In the present embodiment, the slurry containing the particulate matter having a small particle diameter discharged from the upper portion is returned to the feed sump 30. On the other hand, the granular material having a large particle diameter (for example, a granular material of 74 μm or more) contained in the slurry is moved downward while colliding with the inner wall of the main body, and is discharged together with a part of the liquid from a lower discharge port (not shown). Is done.

Therefore, of the oil-contaminated soil in the slurry state charged into the liquid cyclone 41, most of the oily components separated by the granulation device and floating in the treated water are supplied to the feed sump 30 together with the treated water. The soil particles of 74 μm or more from which the oily component has been separated are sent to the spigot tank 42 from the lower outlet, and then sent to the vibrating screen 43 and the dewatering vibrating screen 44, which are classification devices,
Classified into granules of various sizes. From the slurry sent from the spigot tank 42, first, a granular material (soil particles) mainly composed of gravel of 5 mm or more is sieved by a vibrating screen 43, and then a dewatering vibrating screen 44
Thereby, a granular material (soil particles) mainly composed of sand and gravel of 74 μm to 5 mm is classified. The dehydration vibrating screen 4
The slurry containing fine particles (silt content) of about 74 μm or less that passed through 4 is returned to the feed sump 30 again.

On the other hand, the supernatant of the feed sump 30 in which much of the oily component is suspended is sent to the thickener tank 45. In the thickener tank 45, the oil content and
The treated water containing fine particles of 4 μm or less is slowly rotated in a tank to perform solid-liquid separation for coagulating and sedimenting solids such as particulates. As described above, the supernatant liquid of the thickener tank 45 contains an oily component, and is sent to the treated water tank 51 of the water treatment section 50 for treatment. In the treated water tank 51, the oily component is condensed and solidified by chemical treatment or the like, separated from the treatment liquid, and sent to the liquid filtration device 52.
On the other hand, the slurry precipitated at the bottom of the thickener tank 45 is temporarily stored in the slurry tank 46. Since the oily component has been removed from the slurry, the slurry is sent to a dehydrator 47, and a dewatered cake is prepared from the slurry by a filter press (not shown) and carried out to a final disposal site. Also,
The water dehydrated by the dehydrator 47 is sent to the liquid filtration device 52 after being treated in the treated water tank 51. In the liquid filtration device 52, the treated water is filtered with an adsorbent such as activated carbon and solidified to remove oily components and purify the treated water. The purified treated water is reused or discharged, and the adsorbent that has adsorbed the oily components is discarded at a final disposal site.

As described above, according to the present embodiment, the soil contaminated by the oily component is refined by the granulating device 20 and the oily soil adhering to the surface of the soil particles of the oil-contaminated soil is reduced. After the separation from the soil particles, the hydrocyclone 4
1 so as to remove the oil component,
The oily component can be efficiently separated and removed from the oil-contaminated soil. In other words, when classifying the slurry containing the oily component discharged from the grain refiner 20, when using a classifier using a net such as a vibrating screen, the oily component adheres to the net. Therefore, the oily component adheres to the soil particles again. However, by using the liquid cyclone 41, the oily component having a relatively small mass can be efficiently removed from particles such as gravel or the like having a particle size of a certain size (for example, 74 μm) or more. It can be well separated and eliminated. Furthermore, since the soil particles having a large particle diameter from which oily components have been removed and discharged from the lower outlet of the liquid cyclone 41 are classified by the vibrating screen 43 or the dewatering vibrating screen 44, sand and gravel are removed from the oil-contaminated soil. And reusable granular material such as fine sand and fine sand can be obtained, and the volume of oil-contaminated soil can be reduced.

In the above-described embodiment, the slurry containing the particulate matter having a small particle diameter discharged from the upper part of the liquid cyclone 41 is returned to the feed sump 30.
You may make it send directly to the thickener tank 45.

[0014]

As described above, according to the first aspect of the present invention, the soil contaminated with the oily component is put into the treatment space, and is compressed into the soil particles of the soil while adding water. By applying the force of mutual rubbing, the soil is refined, and the oily component attached to the surface of the soil particles is separated from the soil particles, and then discharged from the refiner. The slurry is supplied to a liquid cyclone to remove the oil component, so that oily components can be efficiently and reliably separated and removed from oil-contaminated soil,
Soil particles having a relatively large particle diameter from which oily components have been separated can be obtained.

According to the second aspect of the present invention, a classification means is provided downstream of the hydrocyclone for classifying soil particles having a large particle diameter discharged from the lower discharge port of the hydrocyclone,
Since the above-mentioned soil particles have been classified, the reusable oily component can reliably classify the separated soil particles,
Volume reduction of oil-contaminated soil can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration and a processing flow of a system for treating oil-contaminated soil according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a grain refiner according to the present embodiment.

[Explanation of symbols]

Reference Signs List 1 rotating drum, 1W outer blade, 2 rotor, 2W inner blade, 3 ring gear, 4 motor, 5 rotor rotating shaft, 6 rotor driving mechanism, 7 material input port, 11 receiving hopper, 20 grain refiner, 20a Material outlet, 20b Capture net, 30 Feed sump, 30
P feed pump, 40 classifying means, 41 liquid cyclone, 42 spigot tank, 43 vibrating screen, 44 dehydrating vibrating screen, 45 thickener tank, 46 slurry tank, 47 dehydrator, 50 water treatment section, 51 treated water tank, 52 liquid filtration device , 60 water supply department.

Continued on the front page (72) Inventor Takao Tango 2-3-13-1 Shinjuku, Shinjuku-ku, Tokyo Melting Resources Co., Ltd. (72) Inventor Hiroshi Ito 2-1 Tsukudo-cho, Shinjuku-ku, Tokyo Kumagaya Co., Ltd. Gumi Tokyo Head Office (72) Inventor Kenji Kawaguchi 2-1 Tsukudo-cho, Shinjuku-ku, Tokyo Kumagaya Gumi Tokyo Head Office (72) Inventor Yutaka Shinta 265 Sakurazawa, Yorii-cho, Osato-gun, Saitama F term (reference) 4D004 AA32 AA41 AB02 CA01 CA04 CA10 CA13 CA14 CA50 CB09 CB11 CB42 CB43 CB44 CB50 CC03

Claims (2)

[Claims] 1. A method in which soil contaminated with an oily component is introduced into a treatment space, and the soil particles of the soil are subjected to a compressive force and a rubbing force between the particles while adding water to the soil so that the soil is finely divided. After the soil is finely divided by a fine-granulating device for separating oily components attached to the surface of the soil particles from the soil particles, the slurry discharged from the fine-granulation device is subjected to liquid cyclone A method for treating oil-contaminated soil, wherein the oil component is supplied to the soil to remove the oil component. 2. The method according to claim 1, wherein a classifying means is provided downstream of the hydrocyclone for classifying soil particles having a large particle diameter discharged from a lower discharge port of the hydrocyclone, and the soil particles are classified. Treatment method of oil contaminated soil.