KR20210060686A - System and method for thermo-advanced soil flushing using electric resistance heating - Google Patents

Abstract

Disclosed is a thermo-advanced soil cleaning system using electric resistance heating for cleaning a site of a large-scale oil handling facility in a costal landfill polluted with oils, and a method thereof. The thermo-advanced soil cleaning system using electric resistance heating comprises: well pipes to clean polluted soil; electrode bars inserted into an underground to provide electric resistance heating; a power supply to suply power to the electrode bars; a temperature masuring device to measure a temperature of the polluted soil; a data logger to store the temperature measured by the temperature masuring device; an injection-extraction facility to inject detergent into the well pipes and to extract the polluted water from the well pipes; and a controller for controlling detergent for cleaning polluted soil to be injected through the well pipes when the measured temperature is higher than a threshold temperature and for controlling the polluted water to be extracted through the well pipes. Therefore, in order to clean a costal contaminated area with an aquifer, a temperature of a soil is increased to dissolve oils such as bunker C by inserting an electrode bar into a polluted site to provide electric resistance heating to an underground through the electrode bar so that the dissolved oils are extracted as polluted water to increase soil cleaning efficiency.

Description

Thermally enhanced soil cleaning system and method using electric resistance heating {SYSTEM AND METHOD FOR THERMO-ADVANCED SOIL FLUSHING USING ELECTRIC RESISTANCE HEATING}

The present invention relates to a thermally enhanced soil cleaning system and method using electric resistance heating, and more particularly, to a thermally enhanced soil using electric resistance heating for cleaning a site contaminated with oil in a large-scale oil handling facility in a coastal landfill area. It relates to a cleaning system and method.

As of 2018, most oil handling facilities are confirmed to exist on the coast. In addition, most of cement, steel, and chemical companies are present on the coast. This is because the accessibility of shipping is high, so it is easy to supply and demand raw materials and crude oil, and shipping can be used even when transporting large-scale products.

These oil handling facilities have pollution caused by oil and chemical substances due to obsolescence and careless handling of the facilities when supplying raw materials and carrying out finished products. In addition, oil pollution in the underground due to aging buried underground also frequently occurs.

There are diesel petrochemical industrial complexes, ready-mixed concrete production plants, steel plants, and by-product handling facilities at these coastal oil handling facilities. In the case of the facility, unlike general storage and gas stations, benzene, bunker C oil, crude oil, etc., are present as pollutants, not diesel and gasoline pollution.

On the other hand, coastal industrial complexes are mostly landfilled and are affected by seawater. Because seawater is denser than freshwater, it penetrates into the bottom of freshwater.

In addition, since the coastal plant is at sea level, groundwater flows from the plant to the coast, and contaminated water is limited because it is in a reverse gradient direction from the coast to the plant, and there is a limit to the inflow of pollutants to the plant. Therefore, pollutants move from the interface between seawater and freshwater to the bottom, and are highly polluted.

Accordingly, it is necessary to develop a fusion cleaning technology in consideration of the pollution characteristics of the coastal sites contaminated with high concentration/depth in the aquifer.

Korean Patent Registration No. 10-1195399 (Registration date: October 23, 2012, title of invention: Soil cleaning system and method using vertical drainage) Korean Patent Publication No. 2010-0002359 (Publication date: January 7, 2010, title of invention: Selective removal method of pollutants in the aquifer) Korean Patent Registration No. 10-0451976 (Registration date: September 30, 2004, Invention title: Liquid pollutant removal device from soil and groundwater using a mixture of alcohol and air, and a pollutant removal method using the same) Korean Patent Registration No. 10-0925292 (Registration date: September 30, 2009, Title of invention: Cleaning device for soil pollutants and cleaning method thereof) Korean Patent Registration No. 10-0777319 (Registration date: November 12, 2007, title of invention: Vertical injection type cleaning method of TCE contaminated groundwater) Korean Patent Publication No. 2011-0124742 (Publication date: November 17, 2011, title of invention: High-pressure cleaning system for contaminated soil with drainage well and its driving method)

Accordingly, the technical problem of the present invention is to focus on this point, and an object of the present invention is to install an electric resistance heating device through an electrode at the contaminated site to clean the soil in a contaminated area along the coast where an aquifer exists to increase the temperature of the soil. It is to provide a thermally enhanced soil cleaning system using electric resistance heating in parallel with the soil cleaning by raising the temperature.

Another object of the present invention is to provide a thermally enhanced soil cleaning method using the thermally enhanced soil cleaning system.

In order to realize the object of the present invention, a thermally enhanced soil cleaning system using electric resistance heating according to an embodiment includes: a plurality of cleaning wells disposed for cleaning of contaminated soil; A plurality of electrode rods inserted into the ground for cleaning contaminated soil to provide electrical resistance heating to the ground; A power supply device for supplying power to the electrode rods; A temperature measuring device for measuring the temperature of contaminated soil; A data logger for storing a temperature value measured by the temperature measuring device; An injection-extraction facility for injecting a cleaning agent into the cleaning wells for cleaning contaminated soil and extracting contaminated water from the cleaning wells; And a control unit controlling the injection of a cleaning agent for cleaning contaminated soil through the cleaning wells and extracting contaminated water through the cleaning wells when it is checked that the measured temperature is higher than the critical temperature.

In one embodiment, one of R-phase, S-phase, and T-phase power is applied to each of the electrode rods, and when viewed from a plane, an electrode to which the R-phase power is applied, an electrode to which the S-phase power is applied, and a T The electrode to which the phase power is applied may be arranged in a triangular structure to define a triangular shape.

In one embodiment, the spacing between the electrodes may be about 1.5m.

In one embodiment, the power supply may be a voltage and current automatic adjustment type power supply connected to each of the electrode rods and installed with a transformer to prevent ground fault.

In one embodiment, the injection-extraction facility includes a chemical tank for storing a cleaning agent; An injection pump for injecting the cleaning agent stored in the chemical tank into the ground through the cleaning pipe; And an extraction pump for extracting the cleaning liquid or contaminated water in which the contaminants are dissolved from the ground through the cleaning well.

In one embodiment, the extraction pump may include a water ring type vacuum pump having a high extraction pressure to extract contaminated water having a high viscosity.

In one embodiment, the injection-extraction facility includes a gas-liquid separator for separating gas and liquid from the extracted contaminated water and discharging the separated gas to the atmosphere; And an oil-water separator for separating oil and water from the liquid contaminated water separated by the gas-liquid separator.

In one embodiment, the electrode may have a pipe shape.

In one embodiment, the electrode rod may include SUS316 material.

In order to realize another object of the present invention, a thermally enhanced soil cleaning method using electric resistance heating according to an embodiment provides electrical resistance heating in the ground near a plurality of cleaning wells arranged for cleaning of contaminated soil. Inserting a plurality of electrode rods; Supplying power to the electrode rods to increase the temperature of the soil in the area where the electrode rods are disposed; Measuring and storing the temperature of the contaminated soil; Checking whether the measured temperature is a critical temperature; If it is checked that the measured temperature is higher than the critical temperature, injecting a cleaning agent for cleaning contaminated soil through the cleaning well; Extracting contaminated water through the washing wells; Separating gas and liquid from the extracted contaminated water; Separating oil and water from the separated liquid contaminated water; And storing the separated oil and reinjecting the separated water.

In one embodiment, the thermally enhanced soil cleaning method using electric resistance heating may further include boosting the supply power applied to the electrodes when the measured temperature is checked to be lower than or equal to the critical temperature. have.

In one embodiment, the separated oil may be bunker C oil, and the detergent may be vegetable heavy oil detergent (NEUTRALENE VG 2020).

In one embodiment, the critical temperature may be 60 degrees Celsius.

According to the thermally enhanced soil cleaning system and method using such electrical resistance heating, for cleaning the soil in a contaminated area along the coast where an aquifer exists, an electrode is inserted into the contaminated site, and electrical resistance heating is provided to the ground through the inserted electrode. The soil cleaning efficiency can be improved by increasing the temperature of and dissolving oil such as bunker C and extracting it as contaminated water.

1 is a block diagram schematically illustrating a thermally enhanced soil cleaning system using electric resistance heating according to an embodiment of the present invention.
2 is a configuration diagram illustrating an example of the injection-extraction facility shown in FIG. 1.
3A is a plan view illustrating an installation structure of an electrode according to a comparative example, FIG. 3B is a photograph of an installation of an electrode according to a comparative example, and FIG. 3C is a graph illustrating temperature and power consumption for each reaction time according to a comparative example. .
4A is a plan view illustrating an installation structure of an electrode according to an embodiment of the present invention, FIG. 4B is a photograph of an installation of an electrode according to an embodiment of the present invention, and FIG. 4C is a temperature for each reaction time according to an embodiment of the present invention. And a graph for explaining power consumption.
5 is a graph for explaining a temperature change according to a reaction time for each of a pipe type and a bar type that can be used as a structure of an electrode.
6 is a graph for explaining a temperature change according to a reaction time for each of SUS304 and SUS316 that can be used as a material of an electrode.
7 is a view for explaining the temperature characteristics of each point according to the electrode spacing.
8A is a table for explaining the viscosity and extraction amount of bunker C oil by temperature, and FIG. 8B is a graph for explaining the viscosity and extraction amount of bunker C by temperature.
9 is a flowchart illustrating a thermally enhanced soil cleaning method using electric resistance heating according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. In the present invention, various modifications may be made and various forms may be applied, and specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific form disclosed, it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing each drawing, similar reference numerals have been used for similar elements. In the accompanying drawings, the dimensions of the structures are shown to be enlarged than the actual size for clarity of the present invention.

Terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of being added.

In addition, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in the present application. Does not.

Oil handling facilities along the coast are large and obsolete. Accordingly, it exhibits large-scale high-concentration and high-depth pollution characteristics. In fact, a number of coastal oil pollution cleaning is still being implemented, and in the case of petrochemical complexes, large-scale pollution, not small-scale pollution such as gas stations, has a great impact on the environment. The main characteristics of coastal pollution are high-depth, high-concentration pollution, and other oil pollutants other than general diesel and gasoline pollution, and there are many sites that require continuous use of facilities, which necessitates an underground cleaning technology.

Bunker C oil is an El Naple material with a specific gravity of 0.92 to 0.99, and in order to extract bunker C oil with a pour point of 30 degrees, the temperature in the groundwater environment, which is 15 degrees Celsius, must be raised to 30 degrees Celsius or higher for extraction efficiency. In particular, it is desirable to maintain the temperature of the ground above 60 degrees Celsius. In addition, due to the characteristics of the boundary surface of seawater and freshwater, even if it is an elnalple material, it has the characteristic that a cleaning plan must be established in consideration of the movement characteristic of being contaminated at a high depth.

Bunker C oil is a material with very low intrinsic mobility, that is, hydraulic mobility, compared to other oil types as it has high viscosity and low solubility. However, a large amount of free phase oil exists due to the continuous leakage from the past and the relatively high pitch coefficient (10 ^{-2 cm/sec) of the coastal sandstone layer due to the maintenance of high oil saturation.}

The underground heat desorption method for restoring contaminated soil in the ground is classified into hot air injection, steam enhanced extraction, electrical resistive heating, and thermal conductive heating. .

In the present invention, since a steady inflow of seawater occurs and the purpose is to maintain the temperature below 100 degrees Celsius, an electric resistance heating method is employed. The electrical resistance heating method generates heat in the soil medium by electrical resistance to the flow of current. Electrodes are arranged in a multi-layer arrangement to reduce thermal uniformity and current density.

The advantages of the electric resistance heating method can be applied to low permeable soil, and preparation work is easier than injecting steam/heated air. In addition, it has the advantage of inexpensive installation and operation costs for electricity supply facilities.

1 is a block diagram schematically illustrating a thermally enhanced soil cleaning system using electric resistance heating according to an embodiment of the present invention.

Referring to FIG. 1, the thermally enhanced soil cleaning system using electric resistance heating according to an embodiment of the present invention includes a plurality of cleaning wells 110, a plurality of electrodes 120, a power supply device 130, and a temperature. It includes a measuring device 140, a data logger 150, an injection-extraction facility 160, and a control unit 170.

The cleaning wells 110 are disposed for cleaning of contaminated soil in the contaminated area along the coast in which the aquifer exists and are connected to the injection-extraction facility 160. The cleaning wells 110 may serve as injection wells into which the cleaning agent is injected, or may serve as extraction wells for extracting contaminated water. In this embodiment, an example in which 25 holes are installed is shown in the washing wells. The extracted contaminated water may flow through the wiring connecting the cleaning wells 110 and the injection-extraction facility 160, and when bunker C oil is included in the contaminated water, in order to prevent solidification due to a decrease in temperature, the above-described wiring has a hot wire. This may be arranged, and a separate insulating material may be coated to increase the protective effect.

The electrode rods 120 are inserted into the ground to clean the contaminated soil and provide electrical resistance heating to the ground. One of R-phase, S-phase, and T-phase power is applied to each of the electrode rods 120. When viewed from a plane, the electrode to which the R-phase power is applied, the electrode to which the S-phase power is applied, and the electrode to which the T-phase power is applied are arranged in a triangular structure to define a triangular shape.

The power supply device 130 supplies power to the electrode rods 120. The power supply device 130 is separately installed and connected to each of the electrode rods 120, and may be a voltage and current automatic adjustment type power supply device in which a transformer is installed to prevent ground fault.

The temperature measuring device 140 measures the temperature of the contaminated soil, and the data logger 150 stores the temperature value measured by the temperature measuring device 140. The temperature measuring device 140 may be inserted into the contaminated soil at a predetermined depth to measure the temperature of the contaminated soil.

The injection-extraction facility 160 injects a cleaning agent into the cleaning wells 110 to clean contaminated soil and extracts contaminated water from the cleaning wells 110.

When the measured temperature is checked to be higher than the critical temperature, the control unit 170 controls the cleaning agent for cleaning contaminated soil to be injected through the cleaning wells 110, and controls to extract the contaminated water through the cleaning wells 110. do.

Specifically, when it is checked that the measured temperature is higher than the critical temperature, the control unit 170 controls to inject a cleaning agent for cleaning contaminated soil through the cleaning wells 110, and controls the contaminated water through the cleaning wells 110. After controlling to extract, control to separate gas and liquid from the extracted contaminated water, and control to separate oil and water from contaminated water in the separated liquid state. On the other hand, when it is checked that the temperature of the contaminated soil is lower than the critical temperature, the control unit 170 controls the temperature of the contaminated soil to increase by driving the power supply unit 130 that supplies power to the electrode rods 120.

As described above, in order to clean the soil in the contaminated area along the coast where the aquifer exists, an electrode is inserted into the contaminated site, and electrical resistance heating is provided to the ground through the inserted electrode to increase the soil temperature, such as bunker C. By dissolving oil and extracting it as contaminated water, soil cleaning efficiency can be improved.

2 is a configuration diagram illustrating an example of the injection-extraction facility shown in FIG. 1.

1 and 2, the cleaning agent contained in the chemical tank 610 is provided to a plurality of cleaning wells through a distributor 612 and supplied to the ground.

As the water ring type vacuum pump 620 is started, the contaminated water in the ground is provided to the gas-liquid separator 624 via the washing pipe and the distributor 622. In this embodiment, the water ring type vacuum pump 620 is an extraction pump selected to increase the extraction pressure in consideration of the characteristics of the contaminated area with high viscosity.

When the gas is condensed by the water ring type vacuum pump 620, heat is generated, and sufficient cooling water must be supplied when the pump is operated to cool the heat generated. The above-described cooling water may be supplied through the cooling water supply pump 630 and the plate-shaped cooler 632. Exhausted liquids, such as gases, require exchange of coolant. Coolant mixed with gas can be separated and recovered through a sealant water separation tank. The recovered cooling water can be recycled in whole or in part. Auxiliary devices can also be used in difficult working conditions.

Gas is supplied to the water ring type vacuum pump 620 by the gas-liquid separator 624, and a liquid composed of oil and water is supplied to the liquid tank 626. The liquid provided to the liquid tank 626 is provided to the oil-water separator 640 by a pump.

The liquid provided to the oil-water separator 640 is separated into oil and water, and the separated water is provided back to the ground through a washing well.

In the case of general soil, the temperature increase hardly occurs as the moisture in the soil pores disappears. However, in the case of an aquifer, the temperature rose to 100 degrees Celsius in about 4 hours.

Hereinafter, the installation structure of the electrode rod inserted into the contaminated soil to increase the temperature of the contaminated soil will be described.

<Installation structure of electrode rod according to comparative example>

3A is a plan view illustrating an installation structure of an electrode according to a comparative example, FIG. 3B is a photograph of an installation of an electrode according to a comparative example, and FIG. 3C is a graph illustrating temperature and power consumption for each reaction time according to the comparative example. .

3A, 3B, and 3C, according to a comparative example, 6 metal rods are inserted into the ground in a hexagonal structure, and each of the metal rods has a three-phase power supply, that is, an R-phase power supply, an S-phase power supply, and a T-phase power supply. Supply phase power. Here, power of the same phase is supplied to the metal rods facing each other.

According to the metal rods arranged in a hexagonal structure, after 30 minutes, the underground temperature was observed at approximately 30 degrees Celsius, and after 60 minutes, the underground temperature was observed at approximately 34 degrees Celsius, and after 90 minutes, the underground temperature was It was observed at about 40 degrees Celsius, and after 120 minutes, the underground temperature was observed at about 50 degrees Celsius. After 150 minutes, the underground temperature was observed at about 60 degrees Celsius, and after 180 minutes, the underground temperature was observed at about 68 degrees Celsius. After that, the temperature gradually decreased over time.

As such, the hexagonal structure of the metal rod gradually decreased from 70 degrees Celsius after increasing the temperature. It can be seen that as the number of electrodes increases, the efficiency decreases by affecting the voltage between the phases.

<Installation structure of electrode rod according to an embodiment of the present invention>

4A is a plan view illustrating an installation structure of an electrode according to an embodiment of the present invention, FIG. 4B is a photograph of an installation of an electrode according to an embodiment of the present invention, and FIG. 4C is a temperature for each reaction time according to an embodiment of the present invention. And a graph for explaining power consumption.

4A, 4B and 4C, according to an embodiment, three metal rods are inserted into the ground in a triangular structure, and each of the metal rods has a three-phase power supply, that is, an R-phase power supply, an S-phase power supply, and a T-phase power supply. Supply phase power.

According to the metal rods arranged in a triangular structure, after 30 minutes, the underground temperature was observed at approximately 30 degrees Celsius, and after 60 minutes, the underground temperature was observed at approximately 34 degrees Celsius, and after 90 minutes, the underground temperature was It was observed at about 40 degrees Celsius, and after 120 minutes, the underground temperature was observed at about 50 degrees Celsius, and after 150 minutes, the underground temperature was observed at about 55 degrees Celsius. In addition, after 180 minutes, the underground temperature was observed to be approximately 88 degrees Celsius, and after 210 minutes, the underground temperature was observed to be approximately 90 degrees Celsius, and after 240 minutes, the underground temperature was observed to be approximately 88 degrees Celsius. It was observed from 90 degrees Celsius to 98 degrees Celsius.

As such, the temperature of the triangular structure of the metal rod was stably increased to 100 degrees Celsius. Therefore, in this embodiment, it is preferable to insert the metal rod into the ground in a triangular structure.

Hereinafter, the efficiency according to the structure and material of the electrode inserted into the contaminated soil to increase the temperature of the contaminated soil will be described.

5 is a graph for explaining a temperature change according to a reaction time for each of a pipe type and a bar type that can be used as a structure of an electrode. Here, the pipe-type electrode has a structure that is 3mm thick and is hollow, whereas the steel-bar electrode has a structure that is entirely made of stainless steel.

Referring to FIG. 5, in the case of a bar-type electrode, after 30 minutes, 34 degrees Celsius, after 60 minutes, 39 degrees, 90 minutes, 43 degrees, 120 minutes, 58 degrees, 150 minutes, 57 degrees Celsius. Showed the temperature in degrees.

In the case of the pipe-type electrode, the temperature was 35 degrees Celsius after 30 minutes, 42 degrees Celsius after 60 minutes, 50 degrees Celsius after 90 minutes, 60 degrees Celsius after 120 minutes, and 69 degrees Celsius after 150 minutes.

As such, the pipe-type electrode showed a higher temperature than that of the bar-type electrode. It is analyzed that the contact area with the soil is an important factor rather than the whole. Therefore, in this embodiment, the electrode is preferably a pipe electrode.

6 is a graph for explaining a temperature change according to a reaction time for each of SUS304 and SUS316 that can be used as a material of an electrode.

6, SUS316 is a high-temperature, low-corrosion stainless steel capable of dissipating 20% more power than SUS304. In the case of coastal areas, if SUS304 is used for a long time, efficiency reduction due to corrosion occurs.

In terms of material, when comparing SUS304 and SUS316, SUS316 can dissipate about 20% more power, and it is preferable to select SUS316 to prevent corrosion when used in seawater.

From the above, it is preferable to select SUS316 as the material of the electrode and to adopt a pipe type having excellent heat transfer efficiency for the structure.

Hereinafter, in order to increase the temperature of the contaminated soil, the temperature according to the installation interval of electrodes inserted into the contaminated soil will be described.

7 is a view for explaining the temperature characteristics of each point according to the electrode spacing.

Referring to FIG. 7, when the distance between the electrodes was 1.0 m, the temperature at points adjacent to the electrodes was maintained at 89 degrees Celsius or more. When the distance between the electrodes was 1.5m, the temperature of the points near the electrodes was maintained at 77 degrees Celsius or more. When the distance between the electrodes is 2.0m, the temperature at points near the electrodes cannot be applied below 60 degrees Celsius.

That is, as a result of temperature monitoring for each phase, it was confirmed that 60 degrees Celsius or more was maintained up to a distance of 1.5 m between electrodes. Therefore, in the embodiment of the present invention, it is preferable to maintain the spacing between the electrode rods of about 1.5m.

After modeling the temperature distribution, it can be seen that the soil becomes a cathode rather than the voltage effect of each phase, and each phase reacts with N, heating the soil to 220V.

Hereinafter, a cleaning chemical injected for cleaning of contaminated soil will be described.

Solubility was tested for distilled water, Tween-80, a commonly used detergent, and vegetable heavy oil detergent (NEUTRALENE VG 2020), respectively. As for the experimental conditions, about 100g of soil (all stone + BC oil) was added to three 200mL beakers, and then distilled water, Tween-80 stock solution, and VG-2020 stock solution were each filled so that the total volume was 200 mL.

In the case of a beaker filled with distilled water in contaminated soil, there was no reaction.

On the other hand, in the case of a beaker filled with Tween-80 undiluted solution in contaminated soil, it was confirmed that the elution appeared insignificant.

In contrast, in the case of a beaker filled with VG-2020 undiluted solution in contaminated soil, black contaminant (BC oil) was eluted.

As a result of these experiments, it was confirmed that in the case of bunker C oil, it is difficult to treat with water, and the application of VG-2020, which is used as a detergent for high boiling point oils than Tween-80, is highly efficient.

Hereinafter, temperature conditions selected for cleaning of contaminated soil will be described.

FIG. 8A is a table for explaining the viscosity and extraction amount of bunker C oil by temperature, and FIG. 8B is a graph for explaining the viscosity and extraction amount of bunker C by temperature.

Referring to FIGS. 8A and 8B, when the temperature of bunker C oil is 15 degrees Celsius, the viscosity is about 225 cSt (sticky), and extraction is impossible. Bunker C oil has a viscosity of about 45 cSt at a temperature of 55 degrees Celsius, and the amount of extraction is about 10 mL/min (slightly thinner). Bunker C oil has a viscosity of about 13cSt Celsius when the temperature is 90 degrees Celsius, and the extraction volume is about 30 mL/min (diluted), so extraction is smooth.

Therefore, the underground bunker C oil needs a temperature condition of at least 60 degrees Celsius.

9 is a flowchart illustrating a thermally enhanced soil cleaning method using electric resistance heating according to an embodiment of the present invention.

1 to 9, a plurality of electrode rods 120 for providing electric resistance heating are inserted into the ground near a plurality of cleaning wells 110 arranged for cleaning of contaminated soil (step S100). The electrode rods are arranged in a triangular structure to define a triangular shape, and are connected to the power supply 130 so that R-phase power, S-phase power, and T-phase power are respectively applied when viewed from a plane.

Power is supplied to the electrode rods 120 to increase the temperature of the soil in the area where the electrode rods 120 are disposed (step S102). As power is supplied to the electrode electrodes 120, the temperature of the contaminated soil gradually increases.

Subsequently, the temperature of the contaminated soil is measured through the temperature measuring device 140, and the measured temperature is stored in the data logger 150 (step S104). The measurement control of the temperature or control of the storage of the measured temperature may be performed by the controller 170.

It is checked whether or not the measured temperature is a critical temperature (step S106). Here, the critical temperature is 60 degrees Celsius. The comparison between the measured temperature and the critical temperature may be performed by the control unit 170.

If it is checked in step S106 that the measured temperature is lower than or equal to the critical temperature, the supply power applied to the electrodes is boosted (step S108) and fed back to step S102. The control for boosting the supply power may be performed by the control unit 170.

In step S106, if it is checked that the measured temperature is higher than the critical temperature, a cleaning agent for cleaning contaminated soil is injected through the cleaning well (step S110). The injection of the cleaning agent may be performed by the control unit 170.

Contaminated water is extracted through the washing wells (step S112). The control of extraction of the contaminated water may be performed by the control unit 170.

Subsequently, gas and liquid are separated from the extracted contaminated water (step S114). The control of the separation of the gas and liquid may be performed by the control unit 170.

Then, oil and water are separated from the separated liquid contaminated water (step S116). The control of the separation of oil and water may be performed by the control unit 170.

Then, the separated oil is stored and the separated water is re-injected (step S118). The control of the re-injection of the water may be performed by the control unit 170.

As described above, according to the present invention

Although the above has been described with reference to Examples, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the following claims. You can understand.

The domestic market related to soil and groundwater to which the technology according to the present invention can be applied is a large market expected to be about 500 billion won in 2020. The technology according to the present invention can be applied to contaminated sites such as military bases, industrial complexes, railway stations, and mountainous terrain, and in particular, can be applied to a number of sites existing in coastal landfill areas.

Meanwhile, the scale of overseas soil and groundwater restoration is expected to increase. In particular, in the case of China, the market size is expected to be around 10 trillion won, and there is a high possibility of potential development of the washing market in Southeast Asia as well as China. As there is no field demonstration case of the technology according to the present invention yet, it is possible to preoccupy the market and secure the market because it is superior in technology. In particular, in the case of petrochemical facilities, most of them are located on the shore, so the technology according to the present invention can be easily applied.

The technology according to the present invention can be used for large-scale oil handling facilities cleaning, free-floating oil in coastal areas, and areas requiring blocking of pollution spread, and also for underground cleaning projects in oil-contaminated areas currently in operation, such as military units, industrial complexes, and railway stations. This is possible. In particular, petrochemical complexes and steel mills have demand for cleaning due to aging facilities, and these areas require cleaning technology that considers the characteristics of coastal landfills. Therefore, technology development is also necessary for the continuous operation of industrial facilities for domestic economic stability.

In addition, in terms of the environment, it is possible to reduce the harm to the human body due to the inability to carry out active pollution cleaning due to the presence of ground facilities, and it is possible to prevent secondary pollution to the sea and to prevent the destruction of the marine ecosystem in advance, thereby reducing additional environmental burden. Can be reduced.

In addition, in terms of economy and industry, it is possible to minimize economic losses through rapid pollution cleaning of contaminated areas along the coast, and contribute to the development of the domestic petrochemical industry.

110: cleaning pipes 120: electrode rods
130: power supply 140: temperature measuring device
150: data logger 160: injection-extraction facility
170: control unit 610: chemical tank
620: water ring type vacuum pump 630: cooling water supply pump
624: gas-liquid separator 640: oil-water separator

Claims (13)

A plurality of cleaning wells arranged for cleaning of contaminated soil;
A plurality of electrode rods inserted into the ground for cleaning contaminated soil to provide electrical resistance heating to the ground;
A power supply device for supplying power to the electrode rods;
A temperature measuring device for measuring the temperature of contaminated soil;
A data logger for storing a temperature value measured by the temperature measuring device;
An injection-extraction facility for injecting a cleaning agent into the cleaning wells for cleaning contaminated soil and extracting contaminated water from the cleaning wells; And
Electricity, characterized in that it comprises a control unit for controlling to be injected through the cleaning wells, and to extract contaminated water through the cleaning wells when the measured temperature is checked to be higher than the critical temperature. Thermally enhanced soil cleaning system using resistance heating. The method of claim 1, wherein one of R-phase, S-phase, and T-phase power is applied to each of the electrode rods,
When observed from the plane, the electrode to which the R-phase power is applied, the electrode to which the S-phase power is applied, and the electrode to which the T-phase power is applied are arranged in a triangular structure to define a triangular shape. Thermally enhanced soil cleaning system. The thermally enhanced soil cleaning system using electric resistance heating according to claim 2, wherein the spacing between the electrodes is about 1.5m. The thermally enhanced soil cleaning system using electric resistance heating according to claim 2, wherein the power supply is connected to each of the electrode rods and is a voltage and current automatic adjustment type power supply equipped with a transformer to prevent ground fault. The method of claim 1, wherein the injection-extraction facility,
A chemical tank for storing a cleaning agent;
An injection pump for injecting the cleaning agent stored in the chemical tank into the ground through the cleaning pipe; And
Thermally enhanced soil cleaning system using electric resistance heating, characterized in that it comprises an extraction pump for extracting the cleaning solution or contaminated water in which the contaminants are dissolved from the ground through the cleaning pipe. The thermally enhanced soil cleaning system using electric resistance heating according to claim 5, wherein the extraction pump comprises a water ring type vacuum pump having a high extraction pressure to extract contaminated water having a high viscosity. The method of claim 5, wherein the injection-extraction facility,
A gas-liquid separator for separating gas and liquid from the extracted contaminated water and discharging the separated gas to the atmosphere; And
Thermally enhanced soil cleaning system using electric resistance heating, characterized in that it further comprises an oil-water separator for separating oil and water from the contaminated water in a liquid state separated by the gas-liquid separator. The thermally enhanced soil cleaning system according to claim 1, wherein the electrode has a pipe shape. The thermally enhanced soil cleaning system using electric resistance heating according to claim 1, wherein the electrode is made of SUS316 material. Inserting a plurality of electrode rods for providing electric resistance heating in the ground near a plurality of cleaning wells arranged for cleaning of contaminated soil;
Supplying power to the electrode rods to increase the temperature of the soil in the area where the electrode rods are disposed;
Measuring and storing the temperature of the contaminated soil;
Checking whether the measured temperature is a critical temperature;
If it is checked that the measured temperature is higher than the critical temperature, injecting a cleaning agent for cleaning contaminated soil through the cleaning well;
Extracting contaminated water through the washing wells;
Separating gas and liquid from the extracted contaminated water;
Separating oil and water from the separated liquid contaminated water; And
A thermally enhanced soil cleaning method using electric resistance heating, comprising the step of storing the separated oil and reinjecting the separated water. The thermally enhanced soil cleaning using electric resistance heating according to claim 10, further comprising boosting the supply power applied to the electrodes when the measured temperature is checked to be lower than or equal to the critical temperature. Way. 11. The method of claim 10, wherein the separated oil is bunker C oil, and the cleaning agent is a vegetable heavy oil cleaning agent (NEUTRALENE VG 2020). 11. The method of claim 10, wherein the critical temperature is 60 degrees Celsius.

Images