RU2372295C1 - Installation for purification of oil-containing liquids - Google Patents

Abstract

FIELD: purification constructions.

SUBSTANCE: invention relates to devices for purification of oil-containing liquids formed during development of oil wells, washing of vehicles intended for oil products transportation, as well as various reservoirs for their storage or processing. Installation contains body equipped with branch pipes for input of oil-containing water, output of clarified water, for removal of oil products and thickened product. In body formed are chamber of flow rate extinguishing, purification chamber, made in form of two thin-layered precipitation tanks, chamber of collection and accumulation of separate oil products equipped with heating device, and chamber of clarified water, equipped with discharge threshold. Thin-layered precipitation tanks are located horizontally parallel to each other, symmetrical relative to horizontal body axle. In each of them several thin-layered units, in which coalescence plates are placed at angle of 45 degrees to each other, are located in a successive way. Body is also equipped with additional branch pipes for steam input and output, for thickened product dilution and for changing pressure in chamber of clarified water.

EFFECT: creation of device able to purify liquids containing both low- and highly viscous oil products or other hydrocarbons, as well as ensuring reliable equipment operation without reduction of installation productivity.

3 cl, 2 dwg

Description

The invention relates to a device for cleaning oil-containing liquids generated during the development of oil wells, washing vehicles designed to transport petroleum products, as well as various containers for their storage or processing.

It can be used in shipbuilding, engineering, food, petrochemical and oil refining industries, as well as in construction, transport, energy and other industries where the formation of effluents containing oil products and organic substances.

Due to the sharp increase in the number of enterprises engaged in the receipt, storage, wholesale and retail sale of petroleum products, the absence at most facilities (oil depots, petrol stations (petrol stations), fuel and lubricant warehouses, fuel oil depots, etc.) of equipped and efficiently operating collection and cleaning systems storm and emergency runoff is an increase in oil pollution.

Oil and oil products, coming into direct contact with water, pollute it, being in various states, the main of which are: free oil, unstabilized dispersions, stabilized dispersions, molecularly dissolved oil, enveloping solid inclusions. The state of oil in oily waters is crucial for choosing a method of treating these waters with a view to purifying them.

For cleaning oil products, power purifiers of various designs are used, the principle of which is to separate the particles of pollution from oil products under the influence of an artificial force field or natural gravity.

These are sedimentation tanks, centrifuges and centrifugal separators of various types: gravity, flotation, coalescing and centrifugal.

Known separation plant "Pematic" company "Salen and Vikander" (Sweden).

The separator consists of three tanks mounted on the same foundation. A screw pump is installed on the same foundation. Cleaning in the separator is two-stage.

Oily water is first fed to a gravity-type separator (first stage), the separation of oil particles in which occurs mainly due to the difference in the density of water and oil product. The pump is installed after the separator, i.e. at the first stage it is not. Thus, the gravity separator operates in a vacuum mode, which significantly increases its cleaning ability, because the dispersing effect of the pump on the oil particles is excluded.

The oil separated in the gravity separator is collected in its upper part and, as it is filled, it is removed to the collection tank by the signal of the oil-water interface level sensor. Then partially purified water is supplied to the filter (second stage).

A granular crystalline material treated with a chemical composition or other material is poured into the volume of the filtering tank. The company’s filters used polymer material made in the form of small "squirrel" wheels. Particles of oil that have not separated in the gravity separator are trapped on the surface of the filter material, and purified water is thrown overboard through the wash water tanks. The regeneration of the filter is carried out by back-flushing with purified bilge water enclosed in a flushing tank. Water is squeezed out of the washing tank by the pressure of compressed air into the filter, where it passes through the filter material at a higher rate than when cleaning oil-containing water. In this case, the oil is washed off from the surface of the filter and its regeneration. After each flushing, a certain amount of water with petroleum products is returned again to the bilge well or bilge water collection tank. However, due to the coalescence of oil particles on the filter surface, their subsequent separation in a gravitational separator will be more efficient. The regeneration process is carried out periodically. The pneumatic and electronic valves that switch the operation of the installation from the cleaning mode to regeneration and vice versa are controlled through the control panel, supplied together with the installation (“Means for cleaning liquids on ships”, Reference edited by I. A. Ivanov, L. “Shipbuilding” , 1984).

The presence of three tanks increases the size of the installation and requires additional piping fittings.

A common drawback of plants containing gravity sedimentation tanks, coalescing separators and filters are: accumulation of oil products in the filter grains, lack of separation of solid particles from wastewater outside the coalescing chamber and, accordingly, clogging of coalescing material, regeneration time, impossibility of removing coarse oil droplets from the plants and etc.

A known installation for the treatment of wastewater from oil products, including a housing with a preliminary sump placed in it, a thin-layer module from inclined corrugated shelves, a filter chamber with a coalescing charge, pipelines for the supply of waste water, drainage of oil products, sludge and purified water, a filter chamber with an adsorbent load and perforated manifold connecting both filter chambers and placed in their upper parts, pipelines for the removal of petroleum products, equipped with regulatory controls drainage in screw cups, while the filter chambers are installed in the direction of the liquid behind the thin-layer module, the coalescing charge is made of granular hydrophobic material, for example polyamide or polyethylene, and the adsorbent charge is made of heat-resistant quartz fiber with high porosity, and the preliminary sump is equipped with a heating collector ( RF patent No. 201375, BI No. 10, 1994).

In practice, this design is close to the well-known installation of the company General Electric, but a filter chamber with an adsorbing charge and a heating collector installed in the pre-sump have been added to it. This installation is not intended for the separation of wastewater containing highly viscous petroleum products, which will drastically reduce the life of the coalescing and adsorbing charge. The placement of the heater in the preliminary sump cannot significantly affect the viscosity of the petroleum products.

A device for cleaning oil-containing water, containing a housing with a bottom, a flow distributor, cavities of contaminated and purified water, an oil collector, a suction device connected to an oil collector and a cavity of contaminated water, the treatment unit is made in the form of a frame with filter-coalescing material arranged in a spiral around central perforated pipe. The spiral of the treatment unit is multi-start, while the input (initial) sections of the multi-start spiral are evenly spaced along the diameter of the treatment unit, and the length of the sedimentation channel L is 700 mm with the diameter of the treatment unit 250 mm. (RF patent No. 2082676, BI 18 - 1997)

The device operates as follows. Contaminated water through the pipe 2 enters the upper part of the housing 1, is evenly distributed along the channels of the flow distributor 5 and at low speed passes through them down towards the treatment unit. In the upper part of the building 1 begins the separation of petroleum products. The separated oil product floats up and is collected in the oil collector 4. Next, the contaminated water enters the treatment unit, where the smallest drops of oil that are not separated in the upper part of the device participate in the coalescence process, both due to surface and intra-pore coalescence. The purified water through the Central pipe 10 and the cavity 21 of the purified water by the pump 23 is discharged outside the device. The movement of fluid in the treatment unit is as follows. When contaminated water flows through the outer layer of the frame 6 to the initial sections of the filter-coalescing material 9, it is purified due to the coalescence of the oil product inside the material. The enlarged oil product as a result of the pressure difference created by the pump in the central pipe 10 and the cavity 20 of contaminated water passes through the pores of the material into the longitudinal channels formed by the following layers of the frame, and the remaining particles of the oil coagulate on the surface of the filter-coalescing material 9, enlarge and are also carried away by the flow water up, and the rest move in two directions, inside the filter-coalescing material through the pores and along the spiral channels around it. The separation process on subsequent layers is similar.

This device has the same disadvantages as the previous counterpart in terms of contamination of filter-coalescing material.

In addition, a two-phase system is separated in it - light oil products and process water, and the contact of contaminated and purified water is not excluded.

A device for wastewater treatment is known, protected by RF patent No. 2163828, published in BI No. 7, 2001. It contains a housing, thin-layer elements, nozzles for removing condensed product and clarified water, a collector for collecting clarified water, and the housing is made in the form of two cylindrical sumps conjugated to each other at an angle of 60 degrees to the horizon, forming as if a two-section sump, and in each section of the thickening chamber, above which thin-layer elements are placed, each thickening chamber is associated with a cavity a loading and unloading pipe, the unloading end of which is connected to a nozzle for withdrawing condensed product, and a collector for collecting clarified water is connected to a clarified water collecting chamber located above the thin-layer elements and a nozzle for removing clarified water, while the ratio of the diameters of the loading and unloading pipe and a cylindrical settler is 1: 2-1: 3.

The main disadvantage of the prototype is that with this design thin-layer elements are tilted at an angle of 60 degrees, which reduces the efficiency of their work, because the flow of wastewater moves towards the rising on the wall of each element of the oil film, preventing its ascent.

In addition, using this device it is impossible to remove highly viscous oil products, because it does not provide for heating of the oil product to reduce their viscosity.

Closest to the claimed technical solution is the installation for the purification of oily wastewater RF patent No. 2205797, published. in BI No. 16 - 2003

The installation comprises a housing, an inlet pipe, a partition, which together with the outer wall of the housing forms a flow energy quenching chamber, a two-section thin-layer sump with vertical coalescing plates installed in it, forming a comb, a grease trap installed in the first section of the sump and containing movable disks mounted on the drum, equipped with scrapers, between the sections of a thin-layer sedimentation tank a collection of separated oil products is placed, equipped with a heater and a first discharge threshold, Amer clarified water with a second discharge threshold set with the possibility of changing its height, pipe for water output to a second discharge threshold set with the possibility of changing its height. Each chamber of the device is equipped with appropriate nozzles for the output of sludge, petroleum products and clarified water.

Installation works as follows. Oily-containing wastewater enters the casing at a speed of 1-2 m / s through the inlet pipe to the flow quenching chamber, where the flow expands and reduces speed. Due to this, the largest mechanical impurities settle in the lower part of the flow quenching chamber, and the main wastewater stream containing oil products in the form of large drops of oil or a finely dispersed emulsion enters the first section of the settler, in which there is a thin-layer module. The thin-layer module is made of separate vertical parallel-located coalescing plates that form gap channels between themselves. The upper edges of the plates, protruding above the partition, form a comb, playing the role of a uniform flow distributor over individual slotted channels. As a result of the fact that the flow enters the upper part of the first section of the sump, and leaves in the opposite diagonal angle, a condensation zone forms in the sump, in which sludge accumulates. When an oil-containing stream passes through slotted channels, a natural process of coalescence occurs, i.e. enlargement of droplets of oil products and due to the difference in the density of water and oil, they float to the surface in the upper sludge zone of the first section of the sump, which plays the role of a reservoir of a layer of oil products.

In addition, coalescing plates capture small drops of oil products, while the droplets adhering to the surface of the plates merge and coarsen, forming a continuous film, which rises up to the same zone under the action of the Poiseuille effect. Since the outer wall of the first section of the sump is made somewhat lower than the walls of the casing, the result is the first discharge threshold through which low-viscosity oil products flow into the collection and accumulation chamber of oil products. However, highly viscous petroleum products cannot flow into this chamber; therefore, to remove them, use an oil trap attached to the cover of the installation so that the movable disks mounted on the drum are immersed in the accumulation zone of the petroleum product. The rotation of the drum is carried out from the engine by connecting its shaft to the shaft of the oil separator with a special gear. Under these conditions, the bulk of the oil is pressed against the movable disks, wetting their surface, and forms a well-retained film on it. This film is removed from their surface by scrapers and flows by gravity into the accumulation chamber of oil products.

Wastewater freed from oil products from the outlet of the first sump flows from below to the inlet of the second section of the sump, which has a similar design.

In slotted channels, more dense solid particles are separated from water. Pushing solid particles to the surfaces of the coalescing plates, the flow carries them out due to the diagonal direction of motion into the stagnant zone, where these particles slowly settle and, as they accumulate, are removed through the nozzle. The clarified water through the second discharge threshold enters the clarified water chamber, from which it is removed by means of a corresponding pipe. The thickened product is removed from the thickening zones and the quenching chamber of the flow energy through the corresponding nozzles. The removal of oil products from the chamber of their accumulation is carried out through the pipe for the removal of oil products, and in order to reduce the viscosity of high-viscosity oil products, a heater is installed in the lower zone of this accumulation chamber.

During operation of the known device revealed the following disadvantages, namely:

- a thin-layer module with coalescing vertically parallel plates could not effectively separate liquids containing viscous petroleum products due to the rapid clogging of the slots of the thin-layer module;

- the presence of an oil separator complicated the design of the device and required additional operating costs associated with cleaning discs, replacing scrapers, etc .;

- the presence of an electric heater inside the oil sump did not provide uniform viscosity of oil products due to local overheating, which made them difficult to pump;

- the presence of viscous sludge made it difficult to remove it from the installation.

The technical task of the invention is to provide a device capable of purifying liquids containing both low- and high-viscosity oil products or other hydrocarbons, as well as ensuring reliable operation of the equipment without reducing the performance of the installation.

The technical result is achieved due to the fact that in a known installation containing a housing equipped with nozzles for introducing oil-containing water and withdrawing clarified water, as well as nozzles for removing oil products and condensed product, moreover, chambers are formed in the housing: quenching the flow energy, treatment, made in in the form of two settling tanks, with a thin-layer module placed in them, consisting of parallel coalescing plates, under which thickening zones are formed, as well as a collection and accumulation chamber for separated oil products equipped with a heating device, and a clarified water chamber, equipped with an unloading threshold set with the possibility of adjusting it in height, changes were made, namely:

- sedimentation tanks are located horizontally parallel to each other symmetrically relative to the horizontal axis of the housing;

- in each of them several thin-layer modules are sequentially placed, in which coalescing plates are located at an angle of 45 degrees to each other;

- the casing is equipped with additional steam inlet and outlet pipes for heating the separated oil products, pipes for diluting the sludge and crushing the collected oil products.

In addition, a pocket is formed in the collection zone (chamber) of the separated oil products by placing two plates at an angle to each other, which is connected to the steam inlet and oil discharge pipes, and in the damping zone of the incoming flow rate of the oil-containing liquid, flow distributors are installed in front of the clarifiers.

Placing two settling tanks in the casing allows for improved cleaning and increased plant productivity. The number of thin-layer modules depends on the flow rate of the oily liquid and the required degree of purification from oil products.

Based on practical studies, three thin-layer modules provide the required conditions for the quality purification of an oily liquid.

The location of the coalescing plates at an angle allows you to increase its working time by reducing the clogging of cracks, because heavier substances settle faster in the sludge collection area.

As a result of the experiments, it was found that the most optimal angle of inclination is 45 degrees.

The formation of an inclined pocket in the oil collection zone, into which steam is supplied to reduce the viscosity of oil products, makes it easier to drain the product.

The use of steam for heating oil products allows in this zone to ensure uniform heating of oil products in the entire pocket.

An additional nozzle for diluting sludge allows you to remove them with high viscosity (the presence of paraffins, tar, etc.).

An additional pipe in the zone of clarified water makes it easier to move viscous petroleum products into the zone of the drain pocket, as well as adjust the upper level of clarified water.

After the clarified liquid exits from the thin-layer sedimentation tanks, plates are installed to ensure that the water flows downward and enters the clarified water zone.

The design of the installation for the treatment of oily wastewater is illustrated by drawings.

Figure 1 is a General view of the installation in the context of a vertical plane.

Figure 2 is a left view after the separators of the flow of oily liquid, as well as elements of the chamber for clarifying the liquid, which are not adequately reflected in figure 1.

In Fig. 1, a frame 1 is shown on which a cylindrical body 2 is mounted, an oil-containing fluid inlet pipe 3, a condensed product outlet pipe (sludge) 4, a flow rate damping chamber 5 inside which a flow distributor 6, a thickened product dilution pipe 7, a chamber 8 are placed collection of condensed product, a thin-layer module 9, in which thin-layer modules 10 are sequentially installed (the second cleaning chamber, located parallel to the first on the other side of the housing axis, has a similar design), camera 11 perishable liquid, a guide baffle 12, a nozzle 13 for draining clarified liquid, a liquid level sensor 14 in the clarification chamber, a chamber (zone) 15 for collecting separated oil products, a level sensor 16 for oil products, plates 17, 19 forming a pocket for draining oil products, a discharge pipe 18 petroleum products, pipes 20, 21 for input and output of steam, respectively.

Figure 2 shows the location of the thin-layer sedimentation tanks 9 relative to the axis of the casing and the design of the coalescing plates forming the thin-layer module 10.

Figure 2 schematically shows the elements of the clarified liquid chamber, which are not visible in figure 1. This is a plate 22, which is installed with the possibility of changing its height and forming a discharge threshold, as well as nozzles 23 connected to valves (not shown) to change the liquid level in the clarification chamber by changing the pressure in it.

The installation is equipped with the necessary sanitary equipment and sensors for monitoring the level, temperature in various areas of the installation, connected to the control system of the installation, which are not shown, because are not the subject of the invention.

As a rule, the installation is part of washing complexes designed for washing railway tanks for the transportation of petroleum products or passenger cars and electric trains.

Installation works as follows. The oil-containing liquid representing the spent washing solution with oil products, after sand traps or coarse filters, enters through two nozzles of input 3 into the housing 2 of the installation at a speed of 1-2 m / s. When entering the housing, the flow expands and reduces speed. Due to this, the largest mechanical impurities settle in the lower part of the damping chamber of the flow rate 5, and the main liquid stream containing oil products, which are in the form of large drops of oil or a finely dispersed emulsion, is broken by a flow distributor 6 made in the form of teeth and enters the thin-layer settlers 9, in which there are thin-layer modules 10. The thin-layer module 10 is made of separate parallel located coalescing plates, which are located at an angle of 45 degrees to each other. In SNiP 2.04.02-84 (Guidelines for the design of facilities for water treatment and preparation), the angle of inclination of the coalescing elements of horizontal sedimentation tanks is 50-60 degrees, but for oil-containing waters, thin-layer modules made of coalescing plates at an angle of 45 degrees worked most effectively. When an oil-containing stream passes through slotted channels, a natural process of coalescence occurs, i.e. enlargement of droplets of oil products and due to the difference in the density of water and oil, they float to the surface, forming a zone (chamber) 15 of accumulation of separated oil products.

In addition, coalescing plates capture small drops of oil products, while the droplets adhering to the surface of the plates merge and coarsen, forming a continuous film, which rises up to the same zone under the action of the Poiseuille effect. At the same time, heavier substances (metal particles, sludge, etc.) due to gravitational forces are lowered into the condensed product chamber 8 formed in the lower part of the housing 2.

In this case, three thin-layer modules are installed in the treatment zone of each settler. Depending on the specific conditions (type of oil product, degree of pollution, etc.), their amount may vary.

The washing solution freed from oil products and heavy contaminants from the outlet of the last thin-layer module 10 enters from below into the chamber 11 of the clarified liquid. The direction of flow is ensured by the partition 12. The liquid level in the chamber 11 is initially carried out by setting an overload threshold (plate 22), and as it accumulates, its level sensor 14 issues a command to drain it into a special container through the nozzle 13.

The removal of the separated petroleum products from the chamber 15 is as follows. In this chamber, by means of plates 17 and 19 placed at an angle to each other, a drain pocket is formed, connected to their discharge pipe 18. To facilitate drainage, the viscosity of oil products is reduced by heating the pocket with hot steam. Steam is introduced through the nozzle 20 and removed through the nozzle 21. The separated oil products are drained by the signal of the level sensor 16. With a high viscosity of oil products or an emergency situation, a transfer method is used to ensure the discharge, which is carried out as follows. The valves on the nozzles 23 are opened and due to a change in pressure in this part of the chamber 11, the clarified liquid enters from below and raises the level of oil products in zone 15.

The removal of the condensed product accumulating in zones 8 is carried out through the pipe 4. However, if it is difficult to remove, then water is introduced through the pipe 7 into this zone for dilution.

The regeneration of thin-layer elements is carried out by introducing sharp steam into the housing 2, having previously stopped the cleaning process of the washing solution. It is produced after a certain number of washing cycles or as the quality of the clarified liquid decreases.

Thus, the proposed technical solution has several advantages compared to the technical solutions used for the same purposes, namely:

- structurally, there are no separators with a coalescing charge and with a filtering adsorption charge, requiring periodic replacement and regeneration;

- allows you to clean the oily liquid in a wide range - from low to high viscosity oil products, and their extraction is at least 95-98%, because the degree of water purification is carried out up to 3-5 ppm, which, according to European standards, allows their discharge into natural water bodies;

- increases the reliability of the installation, because the probability of emergency situations during the operation of the installation is excluded.

At present, industrial designs of the installation have been made, which are undergoing pilot tests when using a washing complex for washing railway tanks for the transportation of light and dark oil products.

The installation is scheduled for the end of this year or in the first quarter of 2009.

Claims (3)

1. Installation for cleaning oil-containing liquids, comprising a housing equipped with nozzles for introducing oil-containing water and withdrawing clarified water, as well as nozzles for removing petroleum products and condensed product, moreover, a flow rate damping chamber and a treatment chamber containing two thin-layer sumps are formed in the housing, Thin-layer modules placed in them, made in the form of parallel coalescing plates, under which thickening zones are formed, as well as a clarified water chamber equipped with discharge pore gom, made with the possibility of changing it in height, and a collection of separated petroleum products equipped with a heating device, characterized in that the thin-layer sedimentation tanks are horizontally parallel to each other relative to the axis of the housing and each of them contains several consecutively installed thin-layer modules in which coalescing plates are placed under angle of 45 °, the housing is also equipped with additional nozzles for input and output of steam, additional nozzles for diluting the condensed product and for measuring pressure in the chamber of clarified water. 2. Installation according to claim 1, characterized in that in the collection of separated petroleum products through two plates located at an angle to each other, a drain pocket is formed, heated by steam and connected to the outlet pipe of petroleum products. 3. Installation according to claim 1, characterized in that a distributor is installed in the flow quenching chamber installed in front of the oil-containing fluid inlet into each thin-layer sump.

Images