RU2294803C2 - Method of utilization of oil sludge accumulator - Google Patents

Abstract

FIELD: restoration of soil contaminated with oil.

SUBSTANCE: at first stage, upper layer of oil sludge is collected and refuse is separated on vibrating screen; then oil sludge is subjected to centrifuging for separation of water, remaining refuse and mechanical admixtures. At second stage, middle layer of oil sludge is collected; this layer contains substratum water which is first cleaned from refuse by passing it through vibrating screen; then, water is subjected to centrifuging for separation of oil sludge, remaining refuse and mechanical admixtures from it; they are washed in surfactant solution. At third stage, bottom sediment is collected and is washed in surfactant solution for separation of oil sludge; then, refuse is separated from oil sludge in vibrating screen, after which oil sludge is subjected to centrifuging for separation of remaining water, refuse and mechanical admixtures.

EFFECT: increased degree of separation of oil sludge into cleaned oil sludge, water, refuse and mechanical admixtures.

3 dwg

Description

FIELD OF THE INVENTION

The invention relates to methods for recovering oil-contaminated soil, and in particular, to methods for utilizing sludge collectors.

State of the art

In the Perm Region alone, as a result of oil production, as well as accidents at oil treatment facilities and oil pipelines, more than 500,000 tons of contaminated oil products were generated, which were pumped into special earth tanks - oil sludge collectors in the open air. Evaporation of light oil fractions containing pungent mercaptans constantly occurs from the surface of such sludge collectors (especially in summer). Oil-contaminated liquids containing 3,4-benzapyrene (the most characteristic representative of carcinogens) also seep into the soil and groundwater, resulting in significant environmental damage to the region.

The problem of cleaning soils from oil and oil products is one of the main ones, especially for those regions of the country that are associated with the extraction, transportation and processing of oil.

There is a significant arsenal of methods for eliminating oil pollution of the soil: mechanical, physico-chemical, biological, agricultural, phytomelioration.

Mechanical methods include contamination and pumping of oil in tanks, soil replacement. Spilled oil is also localized by creating with the help of a bulldozer an earthen rampart or a settling pit, from which either oil is sent to a warehouse or sent for further processing.

Physico-chemical methods include dispersion, gelation, soil washing, soil drainage, sorption, thermal desorption. Moreover, in sorption methods, natural and synthetic adsorption materials of organic and inorganic nature are used as sorbents. In some cases, surface-active substances (surfactants) are used to clean oil-contaminated soil, which change the surface tension of the oil film, which contributes to its dispersion and better separation of oil products from soil and soil. Detergents of natural and artificial origin are currently used for these purposes.

Biological methods include bioremediation and phytomelioration - the introduction of active oil-oxidizing microorganisms specially isolated from natural microflora into oil-contaminated soil (soil). In this case, the temperature factor is significant, which determines the intensity of the microbiological decomposition of oil and oil products (20-37 ° C), the pH range at which microorganisms function (from 3.5 to 11), the rate of destruction of oil products (up to 257 mg / kg soil per day, while over 3 months there was 83% soil clearance). For the implementation of bioremediation, such domestic drugs as putidoyl, bacispecin, devoroyl, olevorin are used.

Agrotechnical methods include plowing and loosening of oil-contaminated soil, the application of mineral fertilizers (superphosphate), sowing of green crops, replacing the topsoil with a fertile substrate.

Phytomelioration involves the use of perennial herbaceous plants.

The above methods are difficult to implement and require large amounts of money necessary for the purchase of expensive special equipment, reagents and biological products. They also do not allow the use of oil sludge components as additional raw materials. However, it is obvious that oil sludge from sludge collectors is a valuable source of additional raw materials for oil refineries in the production of road and building bitumen, as well as fuel, provided that the oil sludge pumped from sludge collectors will comply with TU, i.e. purified from mechanical impurities and water (the content of mechanical impurities and water is agreed with the consumer). The cost of petroleum products thus obtained ranges from 4 to 8 thousand rubles / ton. Given the existing volumes of sludge collectors (more than 500 thousand tons), the return of refined oil sludge from sludge collectors as raw materials for these oil products will save tens of millions of rubles.

Currently, a number of companies that work on their own technologies are dealing with the disposal of sludge collectors. So, Green-Service company pumps out liquid petroleum product from the sludge collector, and the sludge collector is filled with soil, which is mixed with oil-contaminated bottom sediment and transported to special earthen plots, after which oil-contaminated soil is treated with a biological product. The Insteb company mixes the oil product from the bottom sediment of a sludge collector with quicklime. As a result, the oil product is encapsulated and becomes non-fluid; while acetylene, hydrogen, carbon monoxide, etc. are emitted into the atmosphere. The Ecolight company has been engaged in the disposal of sludge collectors near Krasnokamsk (Perm Region) for several years, using the technology of sedimentation, evaporation of water from the oil product, which is economically disadvantageous and leads to additional pollution of the atmosphere. Currently, several companies are involved in solving the problem of Ecolight sludge collectors.

The closest analogue (prototype) is a method for the preliminary preparation of oily sludge at the objects of formation during the accumulation of industrial volumes for subsequent processing, which consists in the fact that the oily sludge in the places of formation before collection from the surface of the earth (water) and transportation is subjected to treatment with a composite demulsifier having with high surface activity wetting properties. At the same time, the consumption of the composite demulsifier, depending on the properties of the oil sludge, is 0.02-0.5 kg / t. Then, oil-containing sludge is collected at the places of formation, their further loading and transportation to industrial volume formation objects (Patent RU No. 2195376 C1, class B 09 C 1/00, publication date: 12/27/2002).

The signs of the known method, which coincides with the features of the claimed invention, consist in treating the oil sludge with a solution of a surfactant.

The reason that prevents the obtaining in the known method of a technical result, which is provided by the invention, is that the treatment of oil sludge with a surfactant is carried out before the collection of oil sludge from the surface of the earth or water, which makes it impossible to use the method for disposal of existing oil sludge collectors.

Disclosure of invention

The problem to which the invention is directed, is to simplify the technology of disposal of oil sludge collectors while increasing the degree of separation of oil sludge into purified oil sludge, water, garbage and mechanical impurities.

The technical result, which mediates the solution of this problem, consists in sequential three-stage disposal of the sludge collector in accordance with the natural separation of the sludge in the sludge collector vertically into three zones: the upper layer of sludge, sublayer water and bottom sediment.

The technical result is achieved by the fact that in the method of disposal of oil sludge collector by separating oil sludge into purified oil sludge, water, garbage and mechanical impurities, this separation is carried out in three successive stages: at the first stage, the upper layer of oil sludge is collected, from which garbage is first separated by separating oil sludge on a vibrating screen then centrifugation of the oil sludge is carried out to extract water from it, as well as trash and mechanical impurities, which are then washed in a surface In the second stage, the middle layer of oil sludge is collected, which contains predominantly sub-layer water, from which garbage is first separated by passing it through a vibrating screen, and then water is centrifuged to separate oil sludge from it, as well as trash and mechanical impurities, which are then washed in a solution of a surfactant; in the third stage, a bottom sediment is collected, from which oil sludge is separated by washing the bottom sediment in a surfactant solution substances, then debris is separated from the oil sludge thus obtained by separating the oil sludge on a vibrating screen, after which the oil sludge is centrifuged to separate residual water, garbage and mechanical impurities from it.

New features of the claimed method are the application of the above three consecutive stages.

Brief Description of the Drawings

Figure 1, 2 and 3 shows the functional diagrams of installations for the implementation, respectively, of the first, second and third stages of the method of disposal of sludge collector.

The implementation of the invention

In the first stage, skimmer 1 (Fig. 1) collects oil sludge from the surface of the oil sludge collector, containing mainly oil and oil products, which is piped to the coastal zone in heater 2. In the last, the viscous oil sludge is additionally heated with the help of an integrated coil (steam temperature 100-135 ° C) or hot water (with a temperature of 85-95 ° C) to a temperature of 50-70 ° C to reduce viscosity. Pre-heating of oil sludge at the point of selection for a certain thickness of the film layer is also provided. Next, the heated oil sludge flows by gravity to a vibrating screen 3, where the oil sludge is coarsely cleaned of debris: foliage, grass and floating debris. The oil sludge purified from garbage is sent to a centrifuge 4, where the oil sludge is centrifuged in order to extract water from it, as well as trash and mechanical impurities. The oil sludge thus purified is pumped to a storage tank or to a shipping point for transportation (not shown). In addition, oil-contaminated debris from the exit of the vibrating screen 3, as well as oil-contaminated residues of debris and mechanical impurities from the outlet of the centrifuge 4 are shipped to the mixing vessel 5 with a solution of a surfactant. At the same time, water obtained by the centrifugation of oil sludge is used to prepare the solution. In a stirred tank 5, oil-contaminated debris and mechanical impurities are washed with a surfactant from oil and oil products to a residual content of the last 2-5%, and then sent to a special site for biological treatment (not shown).

In the second stage, the centrifugal pump 6 (figure 2) collect the middle layer of sludge, containing mainly layered water. The latter is served on a vibrating screen 7 to separate debris. Purified water goes to a centrifuge 8, where it is cleaned from oil and oil products. From the exit of the vibrating screen 7, debris, and from the exit of the centrifuge 8, the remains of debris and mechanical impurities are fed into a mixer 9, where debris and mechanical impurities are washed from oil and oil products in a solution of a surfactant.

At the third stage, either the sedimentary pump 10 (commercially available, Osa) or an excavator 10 (Fig. 3) pump out (or collect) the bottom sediment in the form of pulp, which is mainly garbage and other solid particles contaminated with oil sludge. In this case, the bottom sediment is fed into the mixing vessel 11 with a solution of a surfactant, where the film separation of oil sludge from debris and other solid particles occurs. The bottom sediment purified in this way from oil sludge is loaded by conveyors into vehicles for transport to a bioremediation site (not shown). As for oil sludge, it is further heated in a heater 12 and sent sequentially to a vibrating screen 13 for cleaning debris and a centrifuge 14 for fine cleaning of residual debris and water. In this case, the garbage from the output of the vibrating screen 13, contaminated with oil sludge, is returned to the mixing tank 11.

Claims (1)

A method of utilizing an oil sludge collector by separating the oil sludge into purified oil sludge, water, garbage and mechanical impurities, in which the separation is carried out in three successive stages: at the first stage, the upper layer of oil sludge is collected, from which the garbage is first separated by separating the oil sludge on a vibrating screen, and then centrifuged oil sludge to separate water from it, as well as trash and mechanical impurities, which are then washed in a solution of a surfactant, on the second tadia collect the middle layer of oil sludge, containing predominantly sub-layer water, from which garbage is first separated by passing it through a vibrating screen, and then centrifuging water to separate oil sludge, as well as trash and mechanical impurities, which are then washed in a solution of surfactant , at the third stage, the collection of bottom sediment is carried out, from which oil sludge is separated by washing the bottom sediment in a solution of a surfactant, then from the same manner sludge recovered by separation of sludge waste on a vibrating sieve, then slime centrifuged to isolate therefrom the remaining water, debris and impurities.

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