WO2002095137A1

WO2002095137A1 - Apparatus for the removal of liquid floating impurities

Info

Publication number: WO2002095137A1
Application number: PCT/RU2001/000363
Authority: WO
Inventors: Aleksandr Aleksandrovich Evdokimov; Vera Vladimirovna Evdokimova; Vladimir Mikhailovich Smolyanov
Original assignee: Obschestvo S Ogranichennoy Otvetstvennostju 'chistye Tekhnologii'
Priority date: 2001-05-23
Filing date: 2001-09-05
Publication date: 2002-11-28
Also published as: RU2217552C2

Abstract

The apparatus for the removal of liquid floating impurities comprise a load-bearing frame with the possibility to additionally arrange at it not less than one rotating drum, endless belts secured to a basic drum and an additional drum and forming conveyors for the collected impurities transportation, scrapers being intended for cleaning conveyor belts.

Description

APPARATUS FOR THE REMOVAL OF LIQUID FLOATING IMPURITIES

Field of the Invention

The invention relates to the environment protection field, particularly to devices for the removal of crude oil, petroleum products, various oils, grease films and other lubricating agents floating on water surface and can be applied to any branch connected with organic substances removal from water surface.

Description of the Prior Art The problem of cleaning water surface of seas, rivers, lakes and other natural water reservoirs is a matter of topical interest what is confirmed with the diversity of methods and devices offered for its solving through all over the world, many of them being patented. The main source of floating contaminants are ships for oil and petroleum products transportation, as well as results of floating transport means operation, e.g. fuel oil (mazout), various oils and other kinds of liquid fuel or lubricating oils.

An oil trap (GB, 2254801) is known consisting of one or two disc modules arranged in a single casing and consisting of 14 coalescing discs vertically aligned and partially immersed into a contaminated layer of liquid. The disc rotation is driven by a hydraulic motor. While discs are rotating floating oil sticks to their surface and then is scraped off into a chute discharging the removed product into a special pocket. The oil trap is installed at floating transport means or equipped with floats. The removal of collected petroleum products is performed via pipelines connected to an evacuation pump. The drawback of this equipment consists in that it can neither remove separate particles or an intermittent film nor clean water surface of highly viscous floating petroleum products as scrapers are manufactured of soft, J&itetic material. Another oil trap (RU, 2052576) is known which includes a disc shaft, scrapers, an accumulating duct and a propeller. The propeller rotation is performed with the help of a reducer, a chain transmission and a flexible shaft. The propeller angle movement in a horizontal plane relative to the disc shaft is realized with the help of a crank, a tie-rod and an arm. This oil trap allows to remove an intermittent film owing to a screw directing floating oil to a working zone of discs. Still it does not solve the problem of collecting and removing viscous petroleum products. An apparatus for oil removal from water surface (RU, 2073772) is known which is made as a ship with two hulls between which a belt conveyor is installed for oil transportation from water surface into a collecting reservoir.

This apparatus allows to remove petroleum products from water surface absorbing them with sorbents. Compressed air via hoses supplies microcapsules, i.e. sorbents, under an oil film floating on water surface which interact with oil and form gel-like lumps directed to the belt conveyor with the help of special grips.

This equipment ensures the collection of floating petroleum products of any viscosity degree. Still it has some drawbacks the main of which are large expenditures connected with the preparation of sorbents and their further treatment to recover petroleum products; moreover, sorbents should be made of material which would not stick to the conveyor belt.

An apparatus for oil removal from water surface (RU, 2111174) is known which includes a floating oil-collection device and a draining system for petroleum products removal. The oil trapping apparatus is made as four hollow free-floating drums fastened with brackets at sides of a square pan and united with a common drive with the help of a gimbal gear.

External drum surfaces are covered with a fleecy coating, the nap length being 10 mm. They are pressed to spring-loaded comb-shaped scrapers passing to troughs connected with the drain system made as an oil-reception funnel of a centrifugal pump with a discharging flexible hose.

It is actually one of the versions of an oil trap with a brush device of the well- known "Lori" the Finnish company but somewhat complicated and having the same drawbacks as the said oil trap, i.e. both of them are of limited application. They are expedient to be used for the removal of crude oil and other slightly-viscous oil products. The service life of brush devices is comparatively short, therefore it is necessary to often replace them, besides, they are practically useless for highly- viscous petroleum products. An apparatus for the removal of surface layers of oil-containing liquids

(RU, 2134239) is known which is made as two hollow air-tight cylinders with undulating surfaces rotating towards each other inside which additional hollow cylinders are coaxially installed. Cooling or heating agent regulating viscosity of petroleum products to be removed is introduced into the space between the internal and the external cylinders. The similar technical decision of the viscosity regulation of petroleum products to be removed is offered by an apparatus (RU, 2144108) but the drum heating is performed by heating of its external (but not internal) surface by using Ohmic resistances fastened at the external surface of the rotating drum.

The above-mentioned solutions of the problem are connected with large power consumption, besides the apparatuses serviceability is doubtful as petroleum products will have not enough time to be heated to the degree when their viscosity is changed to the required value. Otherwise, the invention purpose will not be reached.

The nearest analog of the apparatus offered is an oil trap (RU, 2017891) including a casing opened for the inlet and the outlet of liquid to be treated, a rotating drum rigidly connected to a system of movable (working) discs, facilities for oil film removal from the disc surfaces and a pocket for petroleum product trapped at the lower part of which a branch pipe is installed to be connected to an evacuating pump. To reduce the viscosity of petroleum product to be removed which accumulates in the pocket a thinner or a heat transfer agent are supplied to it through a branch pipe. The drawback of this apparatus is the use of thinner or heat-transfer agent what is connected with additional power consumption and difficulties in ensuring optimum viscosity of petroleum product to be removed. Brief Summary of the Invention

The invention is based on the object to create an apparatus intended for the removal of liquid floating impurities from water surface irrespective of their viscosity owing to its design elements but not the use of various thinners and / or heat transfer agents as well as sorbents or other water-repellent materials.

The problem raised is solved as follows. The following changes and modifications are introduced into a known apparatus including a casing opened for the inlet and the outlet of liquid to be treated, a rotating drum rigidly connected to a working disc unit, facilities for the removal of impurities from working discs and a drum rotation drive:

- the apparatus casing is made as a load-bearing frame with the possibility to arrange at it additionally not less than one rotating drum with an independent drive made similar to the basic rotating drum and located higher than the basic drum at an acute angle to it; - facilities for the removal of impurities from working discs are made as endless belts secured to the basic drum and the additional drum and forming conveyors for the removal of impurities, the belt width of each conveyor corresponding to the distance between working discs;

- not less than one scraper for the removal of impurities from the conveyor belts is installed at the load-bearing frame, the scrapers' lower part forming a common chute to discharge impurities into the tank. Besides, the apparatus can be equipped with a tray, an inclined transversal trough and an additional vessel for leakages accumulation, the tray and the trough being secured to the load-bearing frame. For the removal and the discharge of especially viscous liquid floating impurities the apparatus is equipped with auxiliary chain conveyors installed between the upper and the lower belts of main conveyors, the auxiliary conveyors sprockets being secured to the shaft of the apparatus basic drum and the second additional drum installed at the load- bearing frame. The distance between axes of the apparatus basic drum and auxiliary conveyors drum is determined on the basis of values of a working disc radius and an additional drum radius. The depth of the working discs immersion into the layer of floating liquid impurities is determined on the basis of a working disc radius, a basic drum radius and a main conveyor belt thickness. Conveyor belts can be made as rubber or plastic bands or metal chains.

If rubber or plastic bands are used shaped slots are cut in surfaces of the basic and additional rotating drums of main conveyors to arrange in them conveyors belts.

If metal chains are used the chain conveyor is actuated with the help of sprockets installed at the main conveyors drums, metal plates being with one of their ends hinged at conveyor chains in such a way that they form a solid plate.

The conveyors quantity in the apparatus is by one piece more than the quantity of working discs installed at the apparatus basic drum.

The apparatus allows to remove from water surface any impurities irrespective of their type and viscosity. At the same time it possesses the design simplicity, the compactness and the reliability of the operation.

Brief Description of the Several Views of the Drawings Fig. 1 - a general view of the apparatus (without facilities for floats fastening and the apparatus mounting at a transportation facility); the conveyor upper run is a loaded (working) one. Fig. 2 - a view in the direction of arrow A, Fig. 1.

Fig. 3 -a view in the direction of arrow B, Fig. 1.

Fig. 4 - a conveyor diagram showing the scraper and the tank arrangement when the conveyor lower run is loaded.

Fig. 5 - a chain conveyor diagram (the upper chain is a loaded one). Fig. 6 - a chain conveyor diagram (the lower chain is a loaded one).

Fig. 7 - a diagram of the apparatus with the use of an auxiliary conveyor. Fig. -8 - a diagram of the apparatus immersion into water with the use of floats.

The apparatus for the removal of liquid floating impurities includes a casing made as a load-bearing frame 1 with stiffening ribs 2.

The lower shaft 3 with the drive 4 and the upper shaft 5 with the drive 6 are installed at the load-bearing frame. The basic drum 7 is installed at the lower shaft 3 and the additional drum 8 is installed at the upper shaft 5, working discs 9 being rigidly secured to the drum 7.

The drums 7 and 8 bear spring-loaded discs 10 which to eliminate the slippage pinch belts of conveyors 11 arranged between them and made as V-shaped rigid belts inserted into shaped slots of drums 7 and 8. A width of each belt of a separate conveyor corresponds to a distance between working discs 9, therefore the belt lateral sides play the role of scrapers removing impurities from lateral surfaces of working discs 9 and supplying them to the drum 8. Ends of drums 7 and 8 bear limiting discs 12 having larger diameters than those of the drums and preventing the extreme conveyor belts πrnning off from drums 7 and 8.

Scrapers 13 secured to the load-bearing frame 1 are installed near drum 8, the scrapers' lower part forming a chute into which impurities are discharged and by gravity supplied to tank 14 installed under the chute. The tank 14 is intended for keeping of collected petroleum products and their periodic transportation (by fuel oil tank trucks, tanks and so on) for the further use of petroleum products.

Taking into account the possibility of leakages during the transportation of slightly- viscous petroleum products the tray 15 is installed under conveyor 11 belts. The tray has an inclined transversal trough 16 by which leakages drain down into the additional vessel 17. To remove too dense and viscous impurities, e.g. tar, bitumen, etc., it is expedient to make conveyor belts 11 in such a way as it is shown in Fig. 5. The chain conveyor is made of metal chains 18 installed on sprockets 19 arranged in shaped slots of drums 7 and 8. To avoid clogging of conveyor chains, metal plates 20 are with one end hinged to each chain link and at the same time play the role of scrapers removing a film of impurities from lateral surfaces of adjacent working discs 9. Plates 20 are installed in such a way that each plate is a continuation of another one thus forming a solid metal band.

In case of the removal of especially viscous impurities when the most important part of a conveyor belt is the zone of working discs passage it is expedient to strengthen this zone using the auxiliary chain conveyor 21 on which working runs of the main conveyors 11 are supported (Fig. 7). Each auxiliary conveyor 21 is installed on the driving sprocket 22 mounted at the shaft 3 of the basic rotating drum 7 and the driven sprocket 23 secured to the additional drum 24 installed at the shaft 25. The distance between axes of drums 7 and 24 is determined by the equation

L > Rι + R₂ (1) where:

L is a distance between axes of the basic and the additional drums (7 and

24), cm Ri is a radius of the working disc, cm R is a radius of the additional drum 24, cm Floats 26 (Fig. 8) are used for keeping the apparatus afloat within the predetermined range of depths. They are fastened to the apparatus stationary parts, e.g. to the load-bearing frame, being adjustable for their height. .

The apparatus can be installed at floating means, e.g. aboard a ship, at booms, at motor transport equipped with a device for the immersion into water, as well at a dam or ashore.

As it has been mentioned the slope of conveyors 11 relative to water surface should be less than 90° to ensure the transportation of impurities of any viscosity. A concrete angle depends on the apparatus working conditions and petroleum products viscosity, therefore to insure optimum capacity an angle should be selected by the attending personnel in the course of the apparatus operation.

The right choice of a depth of working discs 9 immersion into a medium plays the important role for the improvement of the apparatus operation and its capacity as it influences on the quantity of residual liquid to be treated which is contained in collected petroleum products. Therefore the immersion depth of the working discs unit should meet the following requirement

H < Rι - (R₃ - b) (2) where:

H is an immersion depth, cm Ri is a radius of the working disc, cm

R₃ is a radius of the basic rotating drum, cm b is a conveyor belt thickness, cm

The apparatus for the removal of liquid floating impurities operates as follows. The rotation of drums 7 and 8 is provided by independent drives 4 and 6 accordingly, depending on a type of impurity in such a direction that an approaching film of liquid floating impurities (crude oil, petroleum products, grease, oils or other organic impurities) is attacked by descending halves of working discs 9.

Depending on the rotation direction, an upper or a lower run of conveyors 11 is a loaded (working) run; in this case the location of the petroleum product tank 14 and of scrapers 13 removing impurities from the conveyor belts are accordingly changed.

During the removal of slightly- viscous petroleum products, i.e. crude oil, liquid oils, etc., the drive rotates clockwise and the upper run of each conveyor 11 is loaded. The lower run is loaded when the drive rotates counterclockwise (Fig. 1 and Fig. 4).

During the removal and transportation of sufficiently viscous (ointment-like) products (animal fats, fuel oil 100 and so on) the drives 4 and 6 of rotating drums 7 and 8 rotate counterclockwise, i.e. the lower run of conveyors 11 is used as a working one as the velocity of ointment flow is extremely small, therefore it is more convenient to remove the product to be transported from the lower run (Fig. 4).

Thus, during the apparatus operation the basic bulk of floating petroleum product is pressed against working discs 9, wettens their surface and forms on it a firmly clinging impurity film. The film scraps and independent oil particles also floating near the very surface of water are pushed by the flow away from the working discs which are moving downward but still remain in the upper layer of water owing to the Archimedes' principle.

Under the conditions of an ascending flow the lighter oil particles are pressed by the flow against surfaces of discs moving upward, coalesce on their surfaces coated with a film of trapped impurities, then they are scraped by lateral surfaces of conveyor 11 belts and transported upwards to scrapers 13. Impurities are scraped with scrapers 13, move into their lower part which forms a chute and then to tank 14 for keeping collected petroleum _; products and their further transportation.

Leakages of slightly-viscous products are from the conveyor belts drained into- the tray 15, reach the inclined transversal trough 16 and are by gravity directed into the additional vessel 17.

During the removal of too dense and viscous products, e.g. tar and bitumen from water surface it is expedient to use the auxiliary conveyor 21 (Fig. 7). The rotation of the second additional drum 24 is provided by the drive 4 of the basic drum 7 with the help of a standard chain transmission.

Auxiliary conveyors 21 improve the reliability of the main conveyor 11 operation while passing the most dangerous zone, i.e. the zone of working discs.

The advantages of the proposed apparatus in comparison with known technical decisions of the same problem consist in the following:

- the relative simplicity of its design, the compactness and the reliability in the operation; - the apparatus operates irrespectively of a type and properties of floating impurities;

- special thinners or heat exchange agents are not required for the reduction of the viscosity of impurities to be collected and removed.

The Industrial Applicability

The apparatus for the rempval of liquid floating impurities can be applied to any branch of industry where difficulties exist with the removal of hydrocarbons, crude oil, petroleum products and other organic materials from water surface.

The apparatus design neither causes any difficulties during its manufacturing nor ^^uires ~anγ special machining attachments.

Claims

W^claim:

1. An apparatus for the removal of liquid floating impurities from water surface including a casing opened for the inlet and outlet of liquid to be treated, a rotating drum rigidly connected with a working disc unit, facilities for taking off impurities from working discs and a drum rotation drive characterized by the fact that the casing is made as a load-bearing frame with the possibility to arrange at it additionally not less than one rotating drum with an independent drive made similar to the basic rotating drum and located higher than the basic drum at an acute angle to it, facilities for taking off of impurities from working discs are made as endless belts secured to the basic drum and the additional drum forming conveyors for impurities collected, the belt width of each conveyor corresponding to the distance between working discs, not less than one scraper are secured to the load-bearing frame to clean the conveyors belts, the scrapers' s lower part forming a common chute for the discharge of impurities into the tank.

2. An apparatus as claimed in claim 1 characterized with the fact that it is equipped with a tray, an inclined transversal trough and an additional vessel for collecting leakages, the tray and the trough being secured to the load-bearing frame.

3. An apparatus as claimed in claih s 1 or 2 characterized with the fact that it is equipped with auxiliary chain conveyors installed between an upper and a lower belts of main conveyors, the sprockets of auxiliary conveyors being secured to the shaft of the apparatus basic drum and the second additional drum installed at the load-bearing frame.

4. a apparatus as claimed in any one of claims 1 - 3 characterized by the fact that a distance between axes of the apparatus basic drum and an auxiliary conveyor drum is determined by the equation:

where

L is a distance between axes of a basic drum and the second additional drum, cm. R_t and R₂ are radii of a working disc and the second additional drum accordingly, cm.

5. Apparatus as claimed in any one of claims 1 - 4 characterized with the fact that the depth of working disc immersion into a layer of liquid floating impurities is determined on the basis of the equation: H < R- - (R₃ + b) where

H is an immersion depth, cm; Ri is a working disc radius, cm;

R₃ is a basic drum radius, cm; b is a thickness of the main conveyor belt, cm.

6. An apparatus as claimed in any one of claims 1 - 5 characterized with the fact that conveyor belts are made as rubber or plastic bands.

7. An apparatus as claimed in claim 6 characterized with the fact that shaped slots are cut in the surface of the basic and the additional rotating drums of the main conveyors to arrange in them the conveyor belts made as bands.

8. An apparatus as claimed in any one of claims 1 - 5 characterized with the feet that the main conveyor belts are made as metal chains.

9. An apparatus as claimed in claim 8 characterized with the fact that the chain conveyor is actuated with the help of sprockets installed at the main conveyor drums.

10. An apparatus as claimed in claims 8 or 9 characterized with the fact that metal plates are with one of their ends hinged at the conveyors chains in such a way that they form a solid plate.

11. An apparatus as claimed in any one of claims 1 = 10 characterized with the fact that the conveyors quantity is by one piece more than the quantity of working discs installed at the apparatus basic drum.