RU2381995C1 - Method of cleaning soil or oil and oil products and unit to this end - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: proposed device comprises sequentially arranged screen, purified material mixer, screen and pan-funnel mounted there below, auger pump and pipeline to feed liquefied pump in to bins, two bins of sand-slime accumulators, hot water tank, slime centrifugal pump to feed heated water, ejector-water mixer to mix liquefied mass with hot water, hydro cyclone-sand separator and hydro cyclone-slime separator. During the first stage, fouled material is prepared by removing major inclusions to be mixed up with heated water and mincing wood and vegetation inclusions. During the second stage, prepared fouled material is intensity washed by heated water in high-rate turbulent flow of closed hydraulic circuit. At the third stage, liquid and solid phases are separated in hydro cyclone to separate liquid phase into water and oil products. Now water is fed back into cleaning cycle.

EFFECT: higher efficiency.

6 cl, 1 dwg

Description

The invention relates to the protection of the environment, namely the reclamation of lands contaminated with oil and oil products, the disposal of soil, sand, soil and oil sludge.

Known installation for the treatment of oil sludge "Alfa Laval" (prospectus of the company "Alfa-Laval" Installation "Alfa Laval" for the processing of oil sludge "), containing a device for collecting oil sludge, heat exchangers for heating the sludge, fine and coarse filters, a hydrocyclone, a centrifuge , separators. The unit is designed for the processing of liquid sludge and oil recovery.

There is a method for washing the soil (soil, sand) of the company "ERSO" (Promotional brochure "The offer of the company EPKO for the supply of technological systems for environmental restoration", Website: www.epcoequipment.com), including sifting of soil (soil, sand) from large debris on a vibrating screen, jet washing of large particles and sand with a washing liquid with simultaneous separation of fine-grained sludge on an inclined screw conveyor when moving material, a three-stage washing of fine-grained sludge in a container with stirring, combined nnuyu with liquid separation and the solid phase, return washing liquid after the third washing stage fine slurry into a first washing stage and periodic removal of emulsified oil from wash tank.

A known method of cleaning oil-contaminated soils, soils and oil sludge (RF patent No. 224685, CL 02F 1/40, published on January 20, 2005, taken as the closest analogue of the method), in which the soil (soil, sand) is washed with a washing liquid (3 , 0% aqueous solution of detergent with a temperature of 20-80 ° C, forming an unstable emulsion with hydrocarbon contaminants), the liquid is regenerated by phase separation with the separation of the organic phase and the return of the aqueous phase to the cleaning cycle. In this case, before washing, the soil (soil, sludge) is separated into a floating mass and the deposited soil (soil, sludge), and then only each separated fraction is washed. The process involves washing the floating mass by blasting on a vibrating screen by simultaneously separating the washed mass from the contaminating washing liquid. Washing the deposited soil (soil, sand) is carried out in three stages. At the first stage, washing is carried out during deposition in a stream of washing liquid with a volumetric ratio of the deposited soil (soil, sand) and liquid not less than 1: 1. At the second stage, sand is washed by an inclined screw conveyor when moving the material. In the third washing is carried out by blasting on a vibrating screen with the simultaneous separation of the washed soil (soil, sand) from the contaminated washing liquid.

A known line for cleaning oil-contaminated soils, soils and oil sludges (RF patent No. 224686, CL 02F 1/40, published on January 20, 2005, taken as the closest analogue of the device), containing a hopper, a screw conveyor with an integrated jet washing system, capacity oil overflow and floating mass from the hopper, a vibrating screen to separate the floating mass from the contaminated washing liquid, a system for supplying floating mass from the overflow tank to the vibrating screen. The hopper is equipped with a loading grate and a pressure mode installation with the ability to direct the jet to any section of the hopper and mesh. The capacity of oil overflow and floating mass from the hopper is equipped with steam registers inside and has external insulation. The vibrosieve has a drain system and a jet washing unit. The line according to the second embodiment is additionally equipped with a device for supplying a washing solution to the lower part of the hopper.

Known methods and devices are complex and not effective enough, since the jet washing of large particles and sand on a screw conveyor does not ensure their neutralization to a sufficient degree, and the three-stage washing of fine-grained sludge combined with liquid separation requires large volumes of washing liquid and complicates the process. In addition, the complexity of the process is also characterized by a multi-stage cleaning process. The use of detergents at the initial stage of washing requires a large concentration of them. This situation leads to the formation of a large number of decomposition products, which makes it impossible to separate petroleum products from decomposition products. In this regard, oil products released during the refining process lose their commercial quality.

A group of inventions is proposed, including a method for cleaning the soil from oil and oil products and an installation for its implementation.

The objective of the invention is to simplify the process of cleaning oil-contaminated sand (soil, soil), improving the quality of washing, ensuring high productivity of the process and the cleaning process in a closed cycle without the use of a detergent in the first cleaning cycle.

The proposed method and device are more economical and allow you to clean the mixture of soil, plant residues, rocks, solid sludge, solid-liquid pulp-like sludge, while ensuring high quality washing and the cyclic process with multiple return of water to the cleaning cycle.

The technical result for the method and device is to increase the efficiency of soil cleaning.

The claimed technical result in terms of the method is achieved due to the fact that the method of cleaning soils and soils from oil and oil products involves mixing and washing the contaminated material, as well as the separation of the liquid phase into water and oil products. It is characterized by the fact that at the first stage of the cycle, the contaminated material is pre-prepared by removing large inclusions, mixing it with water heated to a temperature of 20-80 ° C and grinding the inclusions of wood and vegetation. At the second stage, pre-prepared contaminated material is intensively washed with water heated to a temperature of 20-80 ° C in a high-speed turbulent flow in elements of a closed hydraulic piping in a volume ratio of water to sand of 10: 1. At the third stage, the liquid and solid phases are separated by the hydrocyclone method and the liquid phase is separated into water and oil products, and water is returned to the treatment cycle.

In a specific embodiment, the cleaning cycle includes washing the contaminated material with water heated to a temperature of 20-80 ° C with or without the use of detergents.

In a particular embodiment, the cleaning cycle may include only two steps.

In a specific embodiment, the entire cleaning cycle of contaminated material or its individual steps can be repeated.

In terms of the device, the technical result is achieved due to the fact that the device for cleaning soils and soil from oil and oil products contains a hopper, a pipeline and a hydrocyclone. It is characterized by the fact that it contains a successively arranged screen for separating inclusions larger than 100 mm, a mixer of contaminated material, a screen for separating stones larger than 5 mm and a funnel pan under it to collect liquefied mass freed from stones. It also contains a screw pump and a pipeline for supplying liquefied mass to the hoppers, two sand silo hoppers, a tank with hot water, a slurry centrifugal pump for supplying heated water, an ejector-hydraulic mixer for mixing the liquefied mass with hot water in a turbulent mode. A hydrocyclone sand separator and a hydrocyclone sludge separator for separating the solid phase, as well as two centrifugal slurry pumps for feeding the liquefied mass to the hydrocyclones. All elements of the device are interconnected by piping to ensure the movement of the cleaned mass.

In a particular embodiment, the device comprises a distribution chute system for guiding the washed material for shipment or for re-cleaning, alternately filling two storage hoppers below the distribution chute system.

In a specific embodiment, the device comprises a pipeline connecting the flow line of the hydrocyclone-desilter with a multifunctional tank.

Contaminated soil, soil, sand, oil sludge containing plant and other residues collected during the cleaning of the earth's surface during emergency oil spills can be used as a washing facility.

The method includes washing the soil (soil, sand) with water heated to a temperature of 20-80 ° C without using detergents with duplication of cleaning cycles, as well as using detergents at the final stage as necessary. During the cleaning process, a solid phase (sand and silt) is released from the mass to be cleaned. At the final stage, the liquid phase is separated into water and oil products with the return of water to the treatment cycle. The method of cleaning the soil (soil, sand) from oil and oil products includes two (or more) repeating cycles that are performed in three (or two) stages each.

At the first stage of the first cycle, contaminated soil (soil, sand) is prepared in advance. The preparation of contaminated material consists in loading and sorting large inclusions (e.g. stones) and removing them. For this, a screen is widely used in the mining industry. Then the contaminated material is mixed with water heated to a temperature of 20-80 ° C. For this, the FSM-7 milling-jet mill can be used, which is widely used for the preparation of flushing liquids when drilling oil and gas wells. In this case, liquefaction and grinding of lumps of contaminated material occurs, grinding of small residues of wood and vegetation. Thus, sorting, removal or grinding of large inclusions, for example, stones larger than 100 mm; removal of wood and vegetation, grinding and liquefaction of lumps of contaminated soil (soil, sand), bitumen inclusions. After that, the liquefied mass is sorted with the removal of stones larger than 5 mm. To do this, a screen is used with a funnel tray located under it.

Further, at the second stage of the cycle, the process of intensive washing of particles of soil (soil, sand) contained in a liquefied mass from oil and oil products in a high-speed turbulent flow of hot water in a volumetric ratio of water to sand of at least 10: 1 is carried out. Washing is carried out, for example, using sequentially installed ejector-mixer, fittings of a closed circulation system, a slurry pump and hydrocyclones without the use of cleaning agents.

Then, in the third stage of the first cycle, the process of final separation of the liquid and solid phases by the hydrocyclone method (for example, using sequentially installed sand and sludge separators) is implemented. The liquid phase that has passed through the entire cycle is divided into two components at the final stage - oil products and water (for example, using a multifunctional tank specially developed for this purpose). In this case, the water returns to the cleaning cycle. The released oil and petroleum products do not lose their consumer properties and can be used as industrial raw materials. In this case, at the end of the cleaning cycle, quality control of the cleaning of the solid phase is carried out.

Polluted water after cleaning cycles is stratified in a multifunctional tank, where oil and oil products accumulate in the upper part of the tank and are sent to a receiving hopper for oil and oil products. Water freed from petroleum products is used in subsequent purification cycles. At the end of sand cleaning, water during disposal is additionally treated with a sorbent.

Upon completion of the cleaning process, environmentally friendly soil (soil, sand), oil and oil products are obtained.

The cycle of washing the soil (soil, sand) can then be repeated depending on the required degree of cleaning the soil (soil, sand).

In the first stage of the second cycle, pre-cleaned sand (still containing organic compounds) is washed in a high-speed turbulent stream of heated water in a hydraulic mixer, in fittings of a closed circulation system, a slurry pump and hydrocyclones with a volume ratio of water to sand of 10: 1.

At the second stage of the second cycle, using the hydrocyclone method, the purified sand is separated from the liquid phase, which at the final stage is separated in a multifunctional tank into water and oil products, as well as their decomposition products.

The possible use of detergent only at the final stage of purification avoids the detrimental effect on the released oil and oil products.

The drawing schematically shows the device and stages of soil cleaning.

The installation comprises a device 1 for separating wood, vegetation, stones larger than 100 mm (for example, a screen or grid-grid with large cells, depending on the parameters of the inclusions of the material being cleaned); stirrer 2 (for example, concrete mixer, twin-shaft clay mixer, milling-jet mill, etc., depending on the condition of the material being cleaned); screen 3 for separating stones larger than 5 mm; funnel pan under the roar 4 to collect liquefied mass freed from stones; screw pump 5, feeding the liquefied mass to the hopper 6 through the pipeline 7, the hopper 8 for the accumulation of wood, vegetation, stones released after sifting on screens, grids; multi-function hot water tank 9; slurry centrifugal pump 10, which supplies hot water through a pipe 11; ejector-hydro mixer 12, mixing the liquefied mass with hot water in turbulent mode, two centrifugal slurry pumps 13 and 14 and two hydrocyclones 15 and 16, operating in series: pump 13 - hydrocyclone (sand separator) 15 - pump 14 - hydrocyclone (sludge separator) 16 and providing separation of the solid phase from the liquid; piping elements connecting the multifunctional tank, pumps, mixers, hydrocyclones, etc. and making the system closed; two sand-silo bins 6 and 17, periodically filled from operating hydrocyclones and released during mixer operation, a system of troughs 18 that send washed sand and silt alternately to the silos or for shipment to a vehicle, pipeline 19 connecting the discharge line of the hydrocyclone-silo separator with a multifunctional capacity 9.

Installation works as follows.

At the stage of preliminary preparation, the material to be cleaned is loaded into a screen 1, where sorting and removal of inclusions larger than 100 mm takes place. Then, the material to be cleaned is sent to a stirrer 2, where mixing with heated water and grinding of large inclusions takes place. Next, the material to be cleaned enters screen 3, where stones are separated over 5 mm in size. All material sorted after the screens is collected in the hopper 8. Under the screen 3 there is a funnel tray 4, where the liquefied mass freed from stones is collected. Further, through the screw pump through the pipeline 7, the liquefied mass is fed into the hopper 6.

At the stage of cleaning, simultaneously with the supply of the mass to be cleaned to the hopper, heated water from the multifunctional tank is pumped through a pipe 11 to the ejector-hydro mixer 12, which mixes the liquefied mass coming from the hopper 6 with hot water in a turbulent mode using a centrifugal pump 10.

Next, the process of separation of liquid and solid phases. From the ejector-hydro mixer 12, the mass to be cleaned is fed by means of a centrifugal slurry pump 13 to the hydrocyclone 15 of the sand separator, after which the mass to be cleaned is fed to the hydrocyclone sludge separator 16 by means of a centrifugal slurry pump 16. Then, the cleaned solid phase is sent for unloading via the gutter system. In a repeated cleaning cycle, the solid phase is sent through a gutter system to the hopper 17 for re-cleaning.

At the stage of separation of the liquid phase, the separated liquid phase, mixed with petroleum products, enters through the pipeline 19 in a multi-functional tank 9, where there is a separation of water from petroleum products. Water is then returned to the purification cycle, and oil products are shipped. At the same time, oil and oil products do not lose their consumer qualities.

Thus, the proposed method and device can neutralize contaminated soil (sand, soil) and ensure the quality of washing while simplifying the cleaning process in comparison with analogues.

Claims (6)

1. A method of cleaning soil and soil from oil and oil products, including mixing and washing the contaminated material, as well as the separation of the liquid phase into water and oil products, characterized in that at the first stage the contaminated material is pre-prepared by removing large inclusions, mixing it with heated up at a temperature of 20-80 ° С with water and grinding wood and vegetation inclusions, at the second stage, pre-prepared contaminated material is intensively washed with water heated to a temperature of 20-80 ° С in a high-speed the rest of the turbulent flow of a closed hydraulic piping at a volume ratio of water to sand of 10: 1, and in the third stage, the liquid and solid phases are separated by the hydrocyclone method and the liquid phase is separated into water and oil products, after which the water is returned to the treatment cycle. 2. The method according to claim 1, characterized in that in the second stage, the contaminated material is washed using detergents. 3. The method according to claim 1, characterized in that the second and / or third stage of purification can be carried out at least twice. 4. A device for cleaning soils and soil from oil and oil products, containing a hopper, pipeline and hydrocyclone, characterized in that it contains successively arranged screens for separating inclusions larger than 100 mm, a mixer of contaminated material, a screen for separating stones larger than 5 mm and a pallet -a gate under it to collect liquefied mass freed from stones, a screw pump and a pipeline for feeding liquefied mass into bunkers, two sand storage tanks, a tank with hot water, a centrifugal slurry a pump for supplying heated water, an ejector-hydraulic mixer for mixing a liquefied mass with hot water in a turbulent mode, a hydrocyclone-sand separator and a hydrocyclone-sludge separator for separating the solid phase, as well as two centrifugal slurry pumps for feeding the liquefied mass to hydrocyclones, while all the elements of the device interconnected by piping to ensure the movement of the cleaned mass. 5. The device according to claim 5, characterized in that it contains a system of distribution troughs for sending the washed material for shipment or for re-cleaning, alternately filling two storage hoppers located below the distribution trough system. 6. The device according to claim 5, characterized in that it contains a pipeline connecting the flow line of the hydrocyclone sludge separator with a multifunctional tank.

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