Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/0208—Separation of non-miscible liquids by sedimentation
  • B01D17/0214—Separation of non-miscible liquids by sedimentation with removal of one of the phases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B17/00—Vessels parts, details, or accessories, not otherwise provided for
  • B63B17/06—Refuse discharge, e.g. for ash
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/40—Devices for separating or removing fatty or oily substances or similar floating material
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/008—Originating from marine vessels, ships and boats, e.g. bilge water or ballast water

Definitions

• the present invention relates to a device and a method for separation of floating sludge oil from water in a storage tank, often referred to as a sludge tank, for petrochemical waste products, typically onboard a ship or in a land based facility with a similar function.
• a storage tank or sludge tank contains oil waste products mixed with water.
• the liquid level in this tank often varies markedly, and hence the device is adapted to follow these marked level changes and simultaneously perform effectively as an oil separator.
• the invention is adapted for operation at sea with sea motion as a natural environmental factor.
• Bilge water is volumes of water which is generated during he normal operation of the ship, and originates for example from condensation and washing water.
• the bilge water separators effectively removes the oil content in the bilge water all the way down to zero ppm.
• a drawback is, however, that a large amount of oil- containing water is generated in this process, which has to be lead down in a sludge tank prior to being pumped ashore for further processing. It is both costly and time consuming to get rid of this oil-containing water by means of currently available systems.
• Sludge oil which enters the sludge tank originates from separation of the fuel used by the ship 's motors for propulsion and generation of electricity.
• crude oil used by the ship 's motors for propulsion and generation of electricity.
• the sludge oil has a sticky but flowing consistency and may advantageously be burnt onboard in the ship 's incinerator or may alternatively be pumped ashore in a more concentrated form.
• the reason why the sludge oil is not used in the ship 's motor, is the content of solid particles and other dirt which will impede an effective injection.
• centrifugal separator Other examples of known solutions for separating oil from the sludge tank onboard a ship is to use a centrifugal separator.
• small separator units are used, which include an elongated cylindrical tank in which the sludge oil/water mix is left to settle, in a similar way as described above in the context of settling in a high tank. The difference between these small separator units and a high tank is that the separator units are placed in the immediate vicinity of the sludge tank, but at a higher level than the sludge tank. In some cases, chemicals are added to speed up the settling process. However, the problem remains also in these cases.
• the centrifugal separator sucks from the bottom layer of the sludge tank, which results in water being separated out and not sludge oil.
• the purified water is pumped into a bilge water tank and the separated sludge oil is collected in a barrel which is then brought ashore as problem waste. This operation involves a lot of onboard manual heavy labour when handling the filled oil barrels.
• a sludge tank is normally positioned adjacent to the ship 's bottom, which means that it is impossible to drain of the surface oil layer by means of gravitation in such a tank, not to mention the environmentally reprehensible and currently prohibited overboard dumping of oil.
• Another drawback of the Andersson device is that the flotation body is allowed to rotate freely about a vertical rod, which means that the evacuation conduit is subjected to very large stress at sea. This solution therefore requires frequent maintenance and has an inherent risk of conduit failure and high maintenance costs.
• a device which always follows the level of the tank content.
• the sludge oil floats on the water surface and the suction hose must thus be positioned close to the surface of the tank content.
• the device of this invention is designed to operate within the sludge tank by continuously following the level of the tank content.
• the sludge oil may be pumped out of the sludge tank and up to a high tank in order to be subsequently burnt, without having to also transport large amounts of water.
• the invention By means of the invention, it is possible to suck out the sludge oil and leave the water in he sludge tank.
• the sludge oil is continually burnt onboard in small quantities and hereby, the lead time is shortened from the point where sludge oil has been generated onboard to the point where the sludge oil has been burnt onboard.
• the invention enables a shortening of the lead time compared to current the available, traditional solutions.
• the content of the sludge tank which in maritime terminology is simply referred to as "sludge", consists mainly of water, often by 70 % or more. Hence, it is easier to remove the sludge oil from the sludge tank since the quantity is less than the quantity of water in the tank. The continuous onboard burning of the sludge oil will vacate tank capacity which would otherwise have been occupied when using traditional methods.
• the invention provides a device for separation of floating sludge oil from water in a storage tank for petrochemical waste products, typically onboard a ship or in a land based facility with a similar function.
• the device comprises a flotation body which - together with a receiving vessel for the sludge oil mounted adjacent to the flotation body - is slidably attached along a guide rod extending in the height direction of the storage tank.
• An evacuation conduit for the sludge oil is provided, said evacuation conduit being positioned adjacent to a bottom portion of the receiving vessel.
• the device according to the invention is particularly characterized in: that the flotation body and the receiving vessel are attached to a common slide sleeve, said slide sleeve being non-rotationally mounted relative to the guide rod by means of rotation locking means, and that the evacuation conduit includes a flexible suction hose coupled to a suction pump arranged for sucking up the sludge oil, said suction pump being positioned outside of the storage tank.
• said rotation locking means includes a guide projection extending radially inwards, said guide projection being adapting for sliding, rotation-locking engagement with a slot extending along the guide rod.
• the guide rod is formed as a hollow pipe, whereby the slot extends along the entire length ofthe hollow pipe.
• said rotation locking means includes a guide projection extending radially outwards, said guide projection being adapted for a sliding, rotation-locking engagement with a slot extending along the slide sleeve.
• a preferred embodiment, in which the flotation body and the receiving vessel exhibit a substantially circular shape in a horizontal plane, is characterized in that the diameter of the receiving vessel exceeds the diameter of the flotation body.
• This embodiment is further characterized in: that the flotation body is positioned above the receiving vessel and exhibits a substantially planar lower surface, and that the receiving vessel - in a vertical plane - exhibits a substantially conical, bowl-shaped portion, whereby a radially outwardly narrowing gap is defined between the lower surface of the flotation body and the conically bowl-shaped portion of the receiving vessel.
• the receiving vessel exhibits a planar, annular edge portion positioned radially outside of said conically bowl-shaped portion.
• the evacuation conduit is mounted in the receiving vessel, but it may alternatively be mounted in a through-hole in the flotation body.
• the suction pump is preferably positioned above the storage tank, whereby the suction hose extends through an opening in the top of the storage tank.
• An embodiment which is advantageous from a maintenance point of view is characterized in: that the guide rod is foldably arranged between a first, erect position of use and a second, folded service position, by means of a mounting foot affixed to the bottom of the storage tank, and that the guide rod further exhibits a connection means at its upper end portion for affixing the guide rod to the top of the storage tank in said erect position of use, said connecting means being disconnectably arranged for folding the guide rod to said service position.
• the inner dimension of the slide sleeve suitably exceeds the outer dimension of the guide rod in such a way that a gap for water and sludge oil is defined therebetween for lubrication between the slide sleeve and the guide rod.
• the flotation body is preferably shaped in such a way as to form a spray hood above the receiving vessel.
• the invention also provides a method for separation of floating sludge oil from water in a storage tank for petrochemical waste products, typically onboard a ship or in a land based facility with a similar function.
• a flotation body which - together with a receiving vessel for the sludge oil mounted adjacent to the flotation body - follows the movements of the water surface in the vertical plane, whilst sliding along a guide rod extending in the height direction of the storage tank.
• the sludge oil is evacuated via an evacuation conduit which is positioned adjacent to a bottom portion of the receiving vessel.
• the method is particularly characterized in: that the sludge oil is pumped out of the storage tank by means of a suction pump positioned outside of the storage tank, through a flexible hose included in said evacuation conduit, and that the evacuation conduit is prevented from being twisted around the guide rod by rotation locking the flotation body and the receiving vessel relative to the guide rod, by means of rotation-locking means on a common slide sleeve at which the flotation body and the receiving vessel is attached.
• the guide rod Upon servicing, the guide rod is folded down from a first, erect position of use to a second, folded service position by disconnecting a connection means between the upper portion of the guide rod and the top of the storage tank. The guide rod is then folded to its service position about a mounting foot, which mounting foot is hinged to a lower end portion of the guide rod and affixed to the bottom of the storage tank.
• the sludge oil is removed directly at the water surface in the sludge tank.
• the level may be effectively maintained in the tank and the effectiveness may be increased by shortening the lead time for the removal of sludge oil.
• the sludge oil may then by further separated for onboard burning in the ship 's incinerators.
• the onboard effectiveness ofthe ship may be increased by using up a larger portion of the fuel whilst the quantities of the oil-containing water to be transported ashore, will decrease.
• the invention is adapted for use in conditions characterized as dirty, corrosive and hot (temperatures around 70° Celsius).
• the device is designed to withstand these conditions without the need for more frequent maintenance than is normally required for cleaning and inspection of the tanks.
• Fig. 1 shows a diagrammatic side view of a device for separation of floating sludge oil from water in a storage tank for sludge oil and water, according to a first embodiment of the invention
• Fig. 2 shows an enlarged, broken, partly cross-sectional side view of the oil- separating device according to the embodiment previously shown in fig. 1 , said device including a flotation body;
• Fig. 3 shows an enlarged cross-sectional view along the dash-dotted line Ill-Ill in fig.
• rotation-locking means includes a guide projection extending radially inwards, said guide projection being adapted for a sliding, rotation- locking engagement with a slot extending along the guide rod;
• Fig. 4 shows a second embodiment of the invention, in which the evacuation conduit is mounted in a through-hole in the flotation body, and
• Fig. 5 finally shows an alternative embodiment of the rotation-locking means including a guide projection being adapted for a sliding, rotation-locking engagement with a slot extending along the slide sleeve.
• reference numeral 1 generally denotes a device for separation of floating sludge oil from water in a storage tank for petrochemical waste products, typically onboard a ship (not shown) or in a land based facility with a similar function. It should be noted that the storage tank 2 is diagrammatically drawn.
• the device 1 will not initially be described with reference to the overview fig. 1 and the enlarged, partly cross-sectional view in fig. 2.
• the device 1 hereby includes a flotation body 3, which - together with a receiving vessel 4 for the sludge oil mounted adjacent to the flotation body 3 - is slideably attached along a guide rod 5 extending in the height direction of the storage tank 2.
• the device 1 further includes an evacuation conduit 6 for the sludge oil, said evacuation conduit 6 being positioned adjacent to a bottom portion 7 of the receiving vessel 4.
• the flotation body 3 and the receiving vessel 4 are both attached to a common slide sleeve 8, which is non-rotationally mounted relatively to the guide rod 5 by means of rotation-locking means 9, as shown in fig. 2.
• the evacuation conduit 6 includes a flexible suction hose 10 coupled to a suction pump 11 arranged for sucking up the sludge oil.
• the suction pump 11 is positioned outside of the storage tank 2 and may for example consist of a pneumatically driven diaphragma pump.
• the suction pump 11 is diagrammatically drawn outside of and above the storage tank 2, whereby the suction hose 10 extends through an opening 12 in the top 13 of the storage tank 2.
• the opening 12 is more particularly positioned in a hatch 14 placed in the top 13 in the storage tank 2.
• a suction filter 15 is positioned upstreams of the suction pump 11.
• the suction hose 10 may be made of reinforced rubber or a rubber-like plastic material.
• said rotation-locking means 9 includes a guide projection 16 extending radially inwards, the guide projection 16 is, in the shown example, welded to a slot 17 formed in the glide sleeve 8, by means of two weld seams 19 positioned on the outside of the glide sleeve. Thereby, the guide projection 16 is adapted for a sliding, rotation-locking engagement with a slot 19 extending along the guide rod 5.
• the guide rod 5 is formed as a hollow pipe 20 in the shown example.
• the slot 19 extends along the entire length of the guide rod 5.
• the flotation body 3 and the receiving vessel 4 exhibit a substantially circular shape in a horizontal plane (i.e. perpendicular to the plane of the drawing sheet).
• the diameter of the receiving vessel 4 exceeds the diameter of the flotation body 3.
• the outer diameter of the receiving vessel 4 is adapted in such a way that the device 1 may be inserted into - or removed from - the storage tank 2 through the hatch 14.
• the flotation body 3 is positioned above the receiving vessel 4 and exhibits a substantially planar lower surface 21.
• the flotation body 3 is hollow and exhibits a cylindrical sleeve surface 22 extending upwardly from said lower surface 21 to a slightly conical top surface 23.
• the conical top surface 23 on the flotation body 3 facilitates drainage of sludge oil deposited on top of the flotation body 3, and it also provides a spray hood over the receiving vessel 4, which prevents surface disturbances in heavy sea motion to interrupt the flow into the receiving vessel 4.
• the flotation body 3 rests with its lower surface 21 on an annular upper shelf 24 which projects from the slide sleeve 8.
• the flotation body 3 is hereby fixed to the slide sleeve 8 by means of a nut 25 which is in a threaded engagement with an upper threaded portion 26 on the slide sleeve 8.
• the flotation body 3 exhibits a central, cylindrical hole 27, through which the slide sleeve 8 extends.
• the receiving vessel 4 exhibits, as is clearly shown in fig. 2, a substantially conical, bowl- shaped portion 28 in a vertical plane.
• a radially outwardly narrowing gap 29 is defined between the lower surface 21 of the flotation body 3 and the conically bowl- shaped portion 28 of the receiving vessel 4.
• the receiving vessel 4 exhibits a planar, annular edge portion 30 positioned radially outside of said conically bowl-shaped portion 28.
• the fact that the narrowing gap 29 is at its narrowest adjacent to the outer diameter of the flotation body 3 and the transition of the bowl-shaped portion 28 in said edge portion 30, results in a local reduction in pressure for an improved suction effect.
• the planar, annular edge portion 30 of the receiving vessel 4 hereby prevents water from being sucked into the receiving vessel 4, at the same time as an advantageous laminar flow of sludge oil is obtained.
• the evacuation conduit 6 is mounted on the receiving vessel 4, more particularly in the conically bowl-shaped portion 28, via a fixed pipe section 31.
• the suction hose 10 is thereby coupled via a quick-attach coupling 32 to the fixed pipe section 31.
• the bottom portion 7 of the receiving vessel 4 is annular and planar with a central-though-going hole 33 for the slide sleeve 8.
• the receiving vessel 4 rests with its bottom portion 7 against a lower annular shelf 34 on the slide sleeve 8.
• the receiving vessel 4 is attached to the slide sleeve 8 by means of several screw joints 35 through the bottom portion 7 and the shelf 34 respectively.
• the receiving vessel 4 may be attached to the slide sleeve 8 in a number of various ways such as for example snap joints (not shown).
• the guide rod 5 is foldably arranged between a first, erect position of use (shown with fully drawn lines) and a second, folded service position (shown with dash-dotted lines), to the left in the figure.
• the guide rod 5 is hinged, at a lower end portion 36, via a mounting foot 37 to the bottom 38 of the storage tank 2.
• the guide rod 5 is hereby intended to be folded about they folding axis 39 being perpendicular to the guide rod 5.
• the guide rod 5 further exhibits a connection means 40 at its upper end portion 41 for affixing the guide rode 5 to the top 13 of the storage tank 2 in said erect position of use.
• the connection means 40 is hereby disconnectably arranged for folding the guide rod 5 to said folded service position.
• the inner dimension of the slide sleeve 8 exceeds the outer dimension of the guide rod 5 in such a way that a gap 42 for water and sludge oil is defined therebetween for lubrication between the slide sleeve 8 and the guide rod 5.
• glide bearings may be positioned between the glide sleeve 8 and the guide rod 5.
• a water surface 43 is shown along with a sludge oil surface 44 at a level slightly above said water surface 43.
• the flotation body 3 is dimensioned in such a way that the annular edge portion 30 on the receiving vessel 4 is positioned in or slightly above the water surface.
• the surface layer of sludge oil which is thus defined between the water surface 43 and the sludge oil surface 44, is normally between 3-5 centimeters in thickness.
• the vertically slideable unit comprised of the flotation body 3, the slide sleeve 8 and the receiving vessel 4. hereby follows the movements of water surface 43 in the vertical plane, during a sliding movement along the guide rod.
• the evacuation conduit 6 includes, as mentioned earlier, a flexible suction hose 10, which is made in such a way that it smoothly follows the vertical movements of the receiving vessel 4 and also allows a folding of the device 1 to its folded service position.
• the length of the suction hose 10 may be adapted to only follow the vertical movements of the receiving vessel 4, whereby the suction hose 10 is disconnected from the receiving vessel 4 by means of the quick-release coupling 32 before folding the device 1 to its service position.
• An essential feature ofthe invention is that the evacuation conduit 6 - during pumping - is prevented from being twisted about the guide rod 5 by rotation-locking of the flotation body 3 and the receiving vessel 4 relative to the guide rod 5 by means of the rotation-locking means 9, i.e. the guide projection 16.
• the evacuation conduit 6 is mounted in a through-hole 46 in the flotation body 3.
• the evacuation conduit 6 has a suction entrance 47 positioned adjacent to the bottom portion 7 of the receiving vessel 4.
• This solution may advantageously be used in storage tanks 2 of lesser dimensions, since the evacuation conduit 6, in these cases, takes up less sideways space.
• the flotation body 3 is furthermore homogenously made in a porous cellular foam material, as opposed to the hollow flotation body 3 which is shown in fig. 1 and 2.
• FIG. 5 an alternative embodiment of the rotation-locking means 9 is shown, which includes a guide projection 48 extending radially outwards, said guide projection 16 being adapted for a sliding, rotation-locking engagement with a slot 19 extending along the slide sleeve 8.
• the guide projection 48 is fixedly attached to the guide rod 5 by means of two weld seams 50.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Ocean & Marine Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Removal Of Floating Material (AREA)
• Cleaning Or Clearing Of The Surface Of Open Water (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20285071

Family Applications (1)

Country Status (2)

Cited By (3)

Citations (3)

• 2001
  • 2001-08-21 SE SE0102771A patent/SE521069C2/sv not_active IP Right Cessation
• 2002
  • 2002-08-20 WO PCT/SE2002/001482 patent/WO2003016223A1/en not_active Application Discontinuation

Patent Citations (3)

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