RU200186U1 - INSTALLATION FOR ELECTROCHEMICAL TREATMENT OF OIL-CONTAMINATED SOILS OF VARIOUS DEGREE OF CONTAMINATION - Google Patents

Abstract

The utility model relates to devices for cleaning and restoring soils contaminated with oil and oil products. The proposed installation for electrochemical cleaning of oil-contaminated soil, consisting of cylindrical cathodes and graphite anodes, connected to a source of direct electric current, immersed in the soil to a depth of pollution by parallel batteries and each connected by its own bus. The installation provides high efficiency of the soil cleaning process.

Description

The utility model relates to devices for cleaning and restoring soils contaminated with oil and oil products.

A device for electrokinetic soil cleaning from organic contaminants is known, which includes two cathode assemblies and an anode assembly located between them, a separation tank with a vacuum pump, a transport pump, a cleaning unit, a correction tank, a dosing peristaltic pump and a direct current source. In the sections of the soil to be cleaned, two cathode cavities and an anode cavity located between them are created, where electrolyte is pumped in and positive and negative DC voltage potentials are supplied to them, after which the electrolyte and the gas phase are supplied from the anode cavity to the cathode ones and back. The electrolytes and gas phases removed from the cathode cavities are mixed, the mixture of gas phases is separated from the mixture of electrolytes, and the separated mixture of gas phases is removed. Then the mixture of electrolytes is cleaned, its composition is corrected and introduced into the anode cavity. The specified circulation of the electrolyte mixture is carried out in a continuous mode until the required degree of soil purification is achieved, (RF patent 2172531, В09С 1/00, published on August 20, 2001 - Method for electrokinetic cleaning of soils from radioactive and toxic substances and a device for its implementation for cleaning soil from organic pollution ).

The main disadvantages of this device and method are the complexity of introducing into the cleaning zone and working with liquid electrolyte, the need for constant monitoring and correction of the composition of the mixture of electrolytes, as well as high operating costs of cleaning and pumping equipment.

The closest technical solution to the proposed utility model (prototype) is an installation implemented in the method of cleaning oil-contaminated soils by passing an electric current through the soil between the anode and cathode electrodes installed in the soil, characterized in that cylindrical cathodes are immersed in the contaminated soil to the depth of contamination. made of steel, and graphite anodes connected to a direct electric current source and located in parallel batteries, each connected by its own bus, the distance between which is determined depending on the radius of the section of cylindrical electrodes, voltage, soil resistivity and depth of pollution (RF patent 2708016, cl . В09С 1/100, published 03.12.2019, bul. No. 34).

The disadvantage is that it does not take into account the possibility of uneven soil contamination with oil products and the need to create a different magnitude of the impact of an electric field.

The task of the utility model is to create a device - an installation for electrochemical cleaning of oil-contaminated soils with the achievement of the following technical result: increasing the efficiency of electrochemical cleaning of soil in areas with different degrees of oil pollution due to changes in the electric field strength when using a single power source.

This problem is solved by the fact that an installation for electrochemical cleaning of oil-contaminated soil, consisting of cylindrical cathodes and graphite anodes connected to a source of direct electric current, immersed in the soil to a depth of pollution by parallel batteries and each connected by its own bus, characterized in that in areas with increased concentration for petroleum products, cylindrical electrodes are made with a cross-sectional radius calculated by the formula

where R _p is the radius of the section of cylindrical electrodes in the area of increased soil contamination;

R _o - the radius of the section of cylindrical electrodes in the rest of the treated area of the soil;

С _п - concentration of pollutants in the area of increased pollution;

C _about - the concentration of pollutants in the rest of the area;

l is the distance between the cylindrical electrodes.

It was found that for the electrochemical cleaning of contaminated soils from oil products, it is required to spend a certain amount of electric charge when passing an electric current to remove 1 kg of oil products, in particular, for chernozem q _beats = 0.7⋅10 ⁷ C / kg, clay soil q _beats = 0 , 63⋅10 ⁷ C / kg, loam q _beats = 0.93⋅10 ⁷ C / kg, sandy soil q _beats = 1.34⋅10 ⁷ C / kg (Pryanichnikova V.V., Shulaev N.S., Bykovsky N.A., Kadyrov PP Features of electrochemical cleaning of various types of soils from oil products // Butlerov Communications. 2018. V. 53. No. 3. P. 124-129.). Therefore, for each type of oil-contaminated soil, the required amount of electric charge Q will be determined by the concentration of oil products

Q = q _beats ⋅C.

At a given voltage U between the electrodes, the cleaning time will be determined by the value of the current I

The current between cylindrical electrodes with a cross-sectional radius R located at a distance l is determined by the relation

where ρ - soil resistivity;

H is the immersion depth of the electrodes.

To clean an area with an area S, 2S / l ² pairs of electrodes are required. Consequently, the total current between the electrodes in the area S will be

Thus, at a given voltage between the electrodes, the processing time of the contaminated area is determined by the initial concentration C of oil products and the volume of the cleaned soil V

The last formula shows that the higher the concentration of oil products, the longer it will take to clean the soil. If the contamination of the areas is non-uniform, that is, there are areas with increased concentration, then in order to reduce the processing time of these areas, it is necessary to install cylindrical electrodes with a large cross-section radius on them so that

It follows from this that the radius of the section of cylindrical electrodes in areas with an increased concentration of oil products will be determined by the formula

Such an increase in the radius of the section of cylindrical electrodes in areas with increased concentration will allow, at a given voltage, to reduce the processing time and, consequently, reduce energy consumption for electrochemical cleaning of the entire oil-contaminated area.

FIG. 1 shows a fragment of an installation (electrode pair) for cleaning soils of various degrees of contamination.

FIG. 2 shows the layout of the electrodes of the installation for cleaning oil-contaminated soils of varying degrees of pollution in the field by electrochemical treatment.

The installation contains a power supply 1; cathodes 2 made of steel; anodes 3 made of graphite; protective cover 4; gas outlet fittings 5 for removing gaseous products of hydrocarbon oxidation; fittings 6 for removing the electrophoretic flow containing oil products.

The installation operates as follows: an electric voltage is applied between the electrodes, an electric current arises that acts on the soil contaminated with oil products, as a result of which one part of the oil products moves under the action of the emerging electrokinetic phenomena to the cathode as a part of the liquid phase together with the pore solution or formation water and is pumped out through the tube; and the other part undergoes oxidation at the anode and in the soil mass. Oxidation of hydrocarbons occurs due to oxygen, hydrogen peroxide and hydroxyl radicals, the formation of which is initiated by electrochemical processes that occur in the soil under the action of an electric current. Gaseous oxidation products are discharged through special valves and collected for further separation and utilization. The production of graphite anodes makes it possible to block the processes of oxidation and destruction, as well as to intensify the electrooxidative reactions.

The magnitude of the current I and the voltage U is set based on the required degree of cleaning and the specified time of soil processing.

The cathodes and anodes are connected by separate buses and immersed in the ground to the depth of penetration of contamination H.

In this case, the degree of soil contamination is taken into account when selecting the dimensions of the electrodes:

The main advantages of the proposed design of the plant for electrochemical treatment of oil-contaminated soil include the following:

- the possibility of simultaneous cleaning of soil areas with different degrees of contamination using a single power source;

- high energy efficiency;

- high productivity and cleaning efficiency due to the optimal placement of the electrodes;

- ease of installation, dismantling and transportation.

The utility model meets the criterion of "industrial applicability" and can be used in the oil-extracting and oil-refining industries for cleaning soils contaminated with oil products to varying degrees at a considerable depth.

Claims (7)

An installation for electrochemical cleaning of oil-contaminated soil, consisting of cylindrical cathodes and graphite anodes connected to a direct electric current source, immersed in the soil to a depth of pollution by parallel batteries and each connected by its own bus, characterized in that in areas with an increased concentration of oil products, cylindrical electrodes are made with a radius section calculated by the formula

where R _p is the radius of the section of cylindrical electrodes in the area of increased soil contamination; R _o - the radius of the section of cylindrical electrodes in the rest of the treated area of the soil; С _п - concentration of pollutants in the area of increased pollution; C _about - the concentration of pollutants in the rest of the area; l is the distance between the cylindrical electrodes.

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