US3680729A - Device for separating two liquids of different densities in a tank containing these two liquids - Google Patents

Device for separating two liquids of different densities in a tank containing these two liquids Download PDF

Info

Publication number
US3680729A
US3680729A US887669A US3680729DA US3680729A US 3680729 A US3680729 A US 3680729A US 887669 A US887669 A US 887669A US 3680729D A US3680729D A US 3680729DA US 3680729 A US3680729 A US 3680729A
Authority
US
United States
Prior art keywords
liquids
tank
skirt
separating element
wall
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US887669A
Other languages
English (en)
Inventor
Gerard Bonavent
Michel Huvey
Marcel Peinado
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
IFP Energies Nouvelles IFPEN
Original Assignee
IFP Energies Nouvelles IFPEN
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by IFP Energies Nouvelles IFPEN filed Critical IFP Energies Nouvelles IFPEN
Application granted granted Critical
Publication of US3680729A publication Critical patent/US3680729A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • B01D17/04—Breaking emulsions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D88/00—Large containers
    • B65D88/78—Large containers for use in or under water

Definitions

  • the separating element may be provided with openings for passages [58] Field of zi gg g g of pipes, the edges of which are also provided with flexible sealing skirts, for filling or emptying the tank. Also, the separating element may include grooves for [56] References Cited draining decanting products from the upper liquid UNITED STATES PATENTS toward the lower q 3,438,215 4/1969 Frijlink across ..'.. --....220/26 D 6 Claims, 9Drawing Figures PATENTEDAUB 1 I972 SHEET 1 BF 3 FIGJ PATENTEmus 1 m2 3.680.729
  • FIGS DEVICE FOR SEPARATING TWO LIQUIDS OF DIFFERENT DENSITIES IN A TANK CONTAINING THESE TWO LIQUIDS It is known that a substantial cost reduction can be obtained in the building of large diarnetered and very high tanks, when the stored product is immiscible or only slightly miscible with water and higher than water, by giving these tanks substantially the shape of a cup turned upside down and at least partly immersed in water The hydrostatic stresses exerted on the periphery of the tank are then reduced substantially and, consequently, the thickness of the tank walls can be substantially reduced.
  • the main object of the invention is accordingly to provide in a tank containing two fluids a separation between these fluids which introduces in the separating elements no stress or at most only a negligible one, due to the differential pressure between the two fluids, avoiding any fixation of the separating element to the periphery of the tank and leaving only an absolutely negligible interface between the two fluids.
  • the floating element may be provided with orifices for the passage of filling or emptying pipes, the edges of said orifices being also provided with flexible sealing skirts.
  • the floating element and the skirt or skirts are so constituted as to have each an apparent density between d and d a and d being the respective densities of the two separate liquids.
  • this apparent density will be selected between 0.8 and 1.3 and preferably between 0.09 and 0.98.
  • FIG. 1 is a diagrammatic overall illustration of an embodiment of the invention
  • FIG. 2 illustrates on a larger scale the peripheral portion of the floating element of FIG. 1, showing in more detail the sealing skirt;
  • FIG. 3 illustrates an embodiment of the central part of this the element; decant;
  • FIG. 4 shows an improved embodiment of the central part of decant; floating element, in the case where the fluid stored in the tank contains suspended products, liable to decant.
  • FIG. 5 is a partial enlarged view showing how the sealing between the two liquids is achieved.
  • FIGS. 6, 6A, 7 and 8 illustrate processes for preforming the sealing skirt.
  • I-I designates the heavier fluid (for example sea water) and L the lighter one (for example crude oil).
  • the floating element 1 may comprise as many sealing skirts 2 as required for the passage of vertical pipes, for example inlet and outlet pipes for the crude oil (pipes and 11) or pipes for discharging the rain water from the roof of the tank, if such a discharging device is used (pipe 12).
  • FIG. 2 shows the detail of the periphery of the floating element, according to FIG. 1, and particularly the flexible self-sustained skirt 3 separating the two liquids, the suitable density of which is obtained either by choosing a homogenous material like polyethylene or a polyvinylchloride (PVC)-polypropylene compound or any other aggregate of thermo-plastic materials and/or elastomers exhibiting the required properties of flexiblity, specific gravity and resistance to the separate fluids.
  • a homogenous material like polyethylene or a polyvinylchloride (PVC)-polypropylene compound or any other aggregate of thermo-plastic materials and/or elastomers exhibiting the required properties of flexiblity, specific gravity and resistance to the separate fluids.
  • PVC polyvinylchloride
  • FIG. 3 shows an embodiment of the central part of the floating element, wherein a suitable average specific gravity, comprised between the above-indicated limits is obtained by using an aggregate of materials having a density respectively higher and lower than the selected average density, for example by constituting said floating element by two layers of glass resin stratified material 4 and 5 separated by a layer 6 of polyurethane foam, the specific gravity of which will be so selected as a function of the respective thicknesses of the different layers 4, 5 and 6 and of the nature thereof, as to obtain the required average density.
  • a suitable average specific gravity comprised between the above-indicated limits is obtained by using an aggregate of materials having a density respectively higher and lower than the selected average density, for example by constituting said floating element by two layers of glass resin stratified material 4 and 5 separated by a layer 6 of polyurethane foam, the specific gravity of which will be so selected as a function of the respective thicknesses of the different layers 4, 5 and 6 and of the nature thereof, as to obtain the required average density.
  • the sealing skirt or skirts may be manufactured in a simple manner by extrusion using a flat drawing plate, by extruding and inflating the material constituting the skirt or by any other suitable means.
  • the fixation of such a flexible skirt to the central part of the floating element may be effected by welding, sticking, or by any other suitable mechanical fixing means.
  • This very flexible skirt of small thickness turns upwardly or downwardly along the tank wall when one proceeds from an emptying period of the tank (position shown in solid line in FIG. 2) to a filling period of this tank (as shown in dotted line) and vice versa.
  • FIG. 4 shows a preferred but not limitative embodiment of the invention, wherein is used, by reason of the ease of manufacture, a homogenous material having the required specific gravity.
  • a high density polyethylene when crude oil must be separated from sea water.
  • a product having a density of 0.95 to 0.96 lying in the above-stated density range, has an excellent chemical resistance to oil products and to sea water, resists also very well to microbial colonies and may be employed economically using processes which are conventional in the art. It is possible, in particular, in the case of large sized floating elements to manufacture strips by extrusion, then join these strips together either by welding or sticking, or also, as in the illustrated embodiment, by mechanical assembling, using an extrusion drawing plate, these strips having profiled parts at their ends in the form of complementary male and female elements for the subsequent mechanical connection of the extruded strips with one another.
  • the profiled strips a variable thickness, so as to constitute in a way catch-drains which make it possible to drain the decanting products (for example sea water suspended in the crude oil) which might settle onto the separating element and enabling, by means of small openings through the bottom of the catch-drain, to return to the lower liquid the products suspended in the upper liquid which are heavier than this liquid.
  • decanting products for example sea water suspended in the crude oil
  • the floating element 7 being formed of strips having a regularly decreasing thickness from the edge to the center of the strip and being provided with central openings 8 which are or not regularly spaced from one another, enabling the decanting products 9 to be drained toward the lower liquid phase.
  • the interface which is left free by such a floating element has an area of about 1. 56 m for an overall cross sectional area of the tank of about 78.6 m and the ratio of this free interval to the overall area will be of about 2 percent, which is far from negligible.
  • this tank is equiped with a flexible skirt according to the invention, leaving at the tank periphery an interface which is about 0.1 mm broad, the area of the interface will only be 3l.4 cm which corresponds to only 40 millionth of the overall area and is absolutely negligible.
  • the additional interface thus introduced will be 0.78 10' m for each m of the tank section, i.e. 0.0078 percent of this tank section, which is again negligible.
  • FIG. 5 is an illustration on a larger scale showing how the flexible skirt provides for sealing between the two fluids H and L.
  • the flexible skirt 2 according to the invention which exerts substantially no stress in the material constituting the floating element 1, when the level of the interface between the two liquids is stationary, also exerts only a negligible stress on this floating element when there is proceeded from a stand-by to an emptying or filling period and vice-versa, which has in particular the advantage of avoiding any risk of a pollution of the fluids one by the other through the draining openings 8 (FIG. 4) as indicated above.
  • this sealing skirt 2 thus turns upwardly or downwardly along the tank wall solely under the action of the hydrostatic forces when there is proceeded from an emptying to a filling period and vice versa, if this skirt is given a thickness which is small enough.
  • R is the radius of curvature, expressed in centimeters, of the tank 13 at the place where the skirt 2 provides for sealing
  • r is the maximum radius of curvature of this skirt, expressed in centimeters
  • E is the average value of the modulus of elastcity for the bending of the material constituting the skirt 2, this modulus of elasticity being expressed in Newtons/m
  • k is a coefiicient equal to (1 d wherein d is the density of the liquid phase H located at the lower part of the tank and d,, is the average density of the flexible skirt 3, (densities relative to water).
  • the length 1 (FIG. 5) of the skirt 2 must be selected sufficient so that this skirt still provides for a separation between the two fluids L and H when the floating element I has been subjected to a horizontal translation and is no more centered within the tank 13.
  • the sealing skirt 2 may be manufactured with a preforming on a matrix of suitable shape, as hereinunder indicated.
  • FIG. 6 illustrates a method for manufacturing the flexible skirt 1 surrounding the floating element 1.
  • the flexible skirt 2 is than constituted by a strip 14 previously cut out by any suitable means, so as to form regularly spaced indentations.
  • This strip is then formed on a matrix 15.
  • This matrix which is diagrammatically illustrated in FIG. 6A, has a cylindrical part 15a having an external diameter equal to the internal diameter 2R of the tank 13.
  • This cylindrical part is connected to the upper part 15b of the matrix through a part 15c of toroidal shape, i.e. through a curved portion, the radius r of which has in this embodiment a substantially constant value, defining the performing radius of the sealing skirt.
  • the adjacent cut out parts 14b are soldered together, using any known process, such as for example an ultrasonic soldering process, with or without addition of soldering material between these out out parts, according to the method which has been selected for cutting strip 14.
  • preforming the flexible skirt may obviously also be used, such as the processes of hot forming of the skirt 2 on a matrix, or also casting or molding processes, for example by injecting the material constituting this skirt into a mold adapted to the shape of the tank.
  • a device for separating two liquids of different densities in a tank containing these two liquid one above the other comprising a separating element of a density less than the density of the lower liquid and greater than the density of the upper liquid floating between these two liquids, said separating element being displaceable with some peripheral clearance along the wall of the tank and being provided at its periphery with a sealing skirt of a radial length exceeding the distance between the separating element and the wall of the tank, wherein said sealing skirt is of small thickness and great flexibility and is constituted of a material having a specific gravity intermediate between those of said liquids so as to be self-sustained at the interface of said liquids and to tangentially engage without substantial frictional force the lateral wall of the tank, being capable of turning upwardly or downwardly along the tank wall without the mixing of the two liquids and also without any substantial force, when the tank is switched from a filling to an emptying operation or vice-versa.
  • a device wherein said separating element is provided with grooves for draining decanting products toward the liquid located below said separating element.
  • a device wherein said separating element is provided with a flexible sealing skirt which is preformed along at least a part of its periphery, so as to be adapted to the curvature of the tank wall whereagainst this skirt is applied.
  • said separating element is provided with at least one opening for the passage there-through of a vertical pipe, the edges of these openings being also provided with a sealing skirt of small thickness and great flexibility constituted of a material having a specific gravity intermediate between those of said liquids so as to be selfsustaining at the interface of said liquids and to tangentially engage without substantial frictional force the lateral wall of the pipe, being capable of turning upwardly or downwardly along the pipe wall without the mixing of the two liquids and also without any substantial force, when the tank is switched from a filling to an emptying operation or vice-versa.
  • a device for separating two liquids of different densities in a tank containing these two liquids one above the other, at least one of which constitutes a stored product including a separating element of a density less than the density of the lower liquid and greater than the density of the upper liquid floating between these liquids, said separating element being displaceable with some peripheral clearance along the vertical wall of the tank, wherein said separating element is provided at its periphery with a very flexible sealing self-sustained skirt of reduced thickness and a specific gravity between those of said liquids capable of applying itself tightly against the vertical wall of the tank and of turning upwardly or downwardly along the tank wall without mixing of the two liquids, when there is proceeded from a filling to an emptying period of the tank and vice versa, said sealing skirt having a thickness at most equal to the value given by the formula:
  • E represents the average value of the modulus of elasticity for the bending of the material constituting said sealing skirt expressed in Newtons/m'-" R is the radius of curvature of the tank wall and r the maximum radius of the skirt at the place where this skirt provides for sealing, the radii R and r being both expressed in centimeters and k is a coefiicient equal to d d,,,, 11 being the density of the heaviest of the two liquids separated by said flexible sealing skirt and d,,, being the average density of this skirt.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
US887669A 1968-12-24 1969-12-23 Device for separating two liquids of different densities in a tank containing these two liquids Expired - Lifetime US3680729A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR180573 1968-12-24

Publications (1)

Publication Number Publication Date
US3680729A true US3680729A (en) 1972-08-01

Family

ID=8659026

Family Applications (1)

Application Number Title Priority Date Filing Date
US887669A Expired - Lifetime US3680729A (en) 1968-12-24 1969-12-23 Device for separating two liquids of different densities in a tank containing these two liquids

Country Status (5)

Country Link
US (1) US3680729A (enrdf_load_stackoverflow)
BE (1) BE743579A (enrdf_load_stackoverflow)
FR (1) FR1603912A (enrdf_load_stackoverflow)
GB (1) GB1287959A (enrdf_load_stackoverflow)
NL (1) NL6919324A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4209271A (en) * 1978-08-10 1980-06-24 Chicago Bridge & Iron Company Storage tank with liquid insulator for storing cryogenic fluids using water displacement
US4241683A (en) * 1978-06-09 1980-12-30 Conway Charles S Liquid cargo tank construction
US4714175A (en) * 1986-12-01 1987-12-22 Cbi Industries, Inc. Tank liquid interface separation deck with leveling lines
US4790447A (en) * 1982-09-13 1988-12-13 Caltex Oil (Australia) Pty. Limited Modification to floating roof tank design
US4957214A (en) * 1982-09-13 1990-09-18 California Texas Oil Corporation Modification to floating roof tank design
US4966295A (en) * 1989-08-11 1990-10-30 Parrish Carolyn L Dieting plate arrangement with movable partitions

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4285078A (en) * 1979-04-17 1981-08-25 French Masterpieces, Inc. Automatic swimming pool cover
US4236258A (en) * 1979-04-17 1980-12-02 French Masterpieces, Incorporated Automatic swimming pool cover

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US593333A (en) * 1897-11-09 Device for separating liquids of different
US2307508A (en) * 1939-10-04 1943-01-05 Du Pont Preventing evaporation from oil storage tanks
US2614717A (en) * 1950-04-28 1952-10-21 John H Wiggins Floating tank roof
US2924350A (en) * 1957-04-23 1960-02-09 David M Greer Storage tanks for liquids
US3049261A (en) * 1959-05-22 1962-08-14 Standard Oil Co Floating blanket
US3159301A (en) * 1962-09-07 1964-12-01 Noel M Anderson Floating diaphragm for pressure tanks
US3164289A (en) * 1962-12-14 1965-01-05 Thomas A Cocchiarella Hermetically sealable container lid
US3438215A (en) * 1966-01-12 1969-04-15 Shell Oil Co Reservoir for storing two fluids

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US593333A (en) * 1897-11-09 Device for separating liquids of different
US2307508A (en) * 1939-10-04 1943-01-05 Du Pont Preventing evaporation from oil storage tanks
US2614717A (en) * 1950-04-28 1952-10-21 John H Wiggins Floating tank roof
US2924350A (en) * 1957-04-23 1960-02-09 David M Greer Storage tanks for liquids
US3049261A (en) * 1959-05-22 1962-08-14 Standard Oil Co Floating blanket
US3159301A (en) * 1962-09-07 1964-12-01 Noel M Anderson Floating diaphragm for pressure tanks
US3164289A (en) * 1962-12-14 1965-01-05 Thomas A Cocchiarella Hermetically sealable container lid
US3438215A (en) * 1966-01-12 1969-04-15 Shell Oil Co Reservoir for storing two fluids

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4241683A (en) * 1978-06-09 1980-12-30 Conway Charles S Liquid cargo tank construction
US4209271A (en) * 1978-08-10 1980-06-24 Chicago Bridge & Iron Company Storage tank with liquid insulator for storing cryogenic fluids using water displacement
US4790447A (en) * 1982-09-13 1988-12-13 Caltex Oil (Australia) Pty. Limited Modification to floating roof tank design
US4957214A (en) * 1982-09-13 1990-09-18 California Texas Oil Corporation Modification to floating roof tank design
US4714175A (en) * 1986-12-01 1987-12-22 Cbi Industries, Inc. Tank liquid interface separation deck with leveling lines
US4966295A (en) * 1989-08-11 1990-10-30 Parrish Carolyn L Dieting plate arrangement with movable partitions

Also Published As

Publication number Publication date
FR1603912A (enrdf_load_stackoverflow) 1971-06-14
GB1287959A (enrdf_load_stackoverflow) 1972-09-06
BE743579A (fr) 1970-05-28
NL6919324A (enrdf_load_stackoverflow) 1970-06-26

Similar Documents

Publication Publication Date Title
US3680729A (en) Device for separating two liquids of different densities in a tank containing these two liquids
US3429128A (en) Offshore storage structure
US4892666A (en) Skimming apparatus and method
US3708987A (en) Concrete reservoir for underwater use
US3327667A (en) Moored production-storage tank
GB1521630A (en) Gravitational separator for immiscible fluids of different densities
US4230138A (en) Method of storing heavy hydrocarbon oil and vessel therefor
US2798633A (en) Storage apparatus
DE2041806A1 (de) Mehrteilige Flanschdichtung
US4790447A (en) Modification to floating roof tank design
NL7903322A (nl) Constructie voor een drukvast, voor het gebruik bij grote duikdiepte geschikte onderwaterromp of -vat.
IT9020972U1 (it) Contenitore per il trasporto di sostanze chimiche
US3273741A (en) Air barrier means for hydropneumatic tank
US2804228A (en) Floating roof for storage tanks
US2893595A (en) Metering system
RU2130799C1 (ru) Устройство для дренажа жидкостей
Hart et al. Expressions for gravity drainage of annular and Toroidal containers
CN106742829A (zh) 一种含油物料储罐内浮盘
CN107303972A (zh) 一种油品储罐内浮盘
US4461599A (en) Apparatus for storing heavy hydrocarbon oil and vessel therefor
GB2566551A (en) Subsea storage of crude oil
FR2424751A1 (fr) Separateur de liquides non miscibles de densites differentes pouvant fonctionner malgre de fortes inclinaisons
CN208635874U (zh) 现场界面计
NO774123L (no) Lense for forurensende vaesker som flyter paa vann
SU1700443A1 (ru) Устройство дл получени стратифицированной жидкости