WO1991012893A1 - Improvements relating to hydrocyclone systems - Google Patents
Improvements relating to hydrocyclone systems Download PDFInfo
- Publication number
- WO1991012893A1 WO1991012893A1 PCT/GB1991/000309 GB9100309W WO9112893A1 WO 1991012893 A1 WO1991012893 A1 WO 1991012893A1 GB 9100309 W GB9100309 W GB 9100309W WO 9112893 A1 WO9112893 A1 WO 9112893A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- water
- hydrocyclones
- hydrocyclone
- flow
- mixture inlet
- Prior art date
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 63
- 239000000203 mixture Substances 0.000 claims abstract description 19
- 238000000034 method Methods 0.000 claims abstract description 8
- 238000013459 approach Methods 0.000 claims abstract description 3
- 238000007872 degassing Methods 0.000 claims description 8
- 239000008213 purified water Substances 0.000 claims description 6
- 238000000926 separation method Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000012530 fluid Substances 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 239000013535 sea water Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
- B04C5/00—Apparatus in which the axial direction of the vortex is reversed
- B04C5/24—Multiple arrangement thereof
- B04C5/28—Multiple arrangement thereof for parallel flow
-
- 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
- B01D17/0217—Separation of non-miscible liquids by centrifugal force
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
- B04C11/00—Accessories, e.g. safety or control devices, not otherwise provided for, e.g. regulators, valves in inlet or overflow ducting
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/34—Arrangements for separating materials produced by the well
Definitions
- Water which may have some oil dispersed within it, is discharged from the three phase separator 3 through a pipe 8 which connects within a bank of hydrocyclones 9, in this case contained within a pressure vessel. At least some of the oil in the water being fed into the hydrocyclones 9 is separated into a discharge stream from the hydrocyclones 9 which is relatively rich in oil. This stream flows through a pipe 10. The other discharge stream from the hydrocyclones 9 flows through a pipe 11 and is at least substantially decontaminated of oil, i.e. this stream consists of purified water.
Landscapes
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mining & Mineral Resources (AREA)
- Chemical & Material Sciences (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Thermal Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Removal Of Floating Material (AREA)
- Physical Water Treatments (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Water Treatment By Sorption (AREA)
- Lubricants (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
- Chairs Characterized By Structure (AREA)
- Detergent Compositions (AREA)
Abstract
A method of operating a system for de-oiling water utilising hydrocyclone separators (9). Each separator (9) has a mixture inlet, an overflow oil outlet (10) and underflow water outlet (11). The flow through at least one hydrocyclone (9) is sensed and, if the flow approaches a threshold below which there is insufficient flow through the respective hydrocyclone (9) for satisfactory operation, an additional supply of water is fed to the mixture inlet.
Description
IMPROVEMENTS RELATING TO HYDROCYCLONE SYSTEMS Hydrocyclones are used for de-oiling the water which is separated from production fluids on offshore oil platforms or other production facilities. A plurality of hydrocylcones are required to cater for the maximum flow rate of water produced from source and these are commonly grouped in banks, often with the different banks within different pressure vessels. Each individual hydrocyclone has a particular inlet flow rate range over which it efficiently separates oil from water and it is important that none of the hydrocyclones are operated in a manner such that the inlet flow rate falls below a minimum value. The flow rate of production fluids can vary appreciably, for example, the production of water can be comparatively low with a young field or upon start up after stoppage. Consequently, means have had to be provided for shutting off different hydrocyclones or banks of hydrocyclones using conventional valve means, and it is desirable that operations personnel be spared the labour- intensive task of switching on and off the various hydrocyclones upon a change in the flow rate of water to be de-oiled.
In accordance with the present invention, in a method of operating a system for de-oiling water, utilising --hydrocyclone separators each having a mixture inlet, an overflow oil outlet and an underflow water outlet, the flow through at least one hydrocyclone is sensed, and if the flow approaches a threshold below which there is insufficient flow through the respective hydrocyclone(s) for satisfactory operation, an additional supply of water is fed to the mixture inlet(s) to maintain the flow safely above the threshold.
The invention is conveniently applied to a plurality of banks of the hydrocyclones, each bank acting in parallel having mixture inlet means leading to the mixture inlets of the hydrocyclones of the respective bank, an outlet means leading from the overflow oil outlets of the hydrocyclones
of the respective bank, and water outlet means leading from the underflow water outlets of the hydrocyclones of the respective bank, wherein the flow through the bank of hydrocyclones is sensed and the additional supply of water is fed to the mixture inlet means to maintain the flow sa ely above the threshold through the hydrocyclones of the respective bank. Each of the banks may be mounted in a respective pressure vessel.
With this arrangement, it is unnecessary to shut down any hydrocyclones upon a reduction in the flow rate of water to be de-oiled, the hydrocyclones being maintained with a sufficient inlet flow for efficient operation by the automatic supply of additional water to the mixture inlets.
The sensing may be carried out indirectly by a differential pressure controller which effectively senses the pressure difference between the mixture inlet and underflow water outlets of the individual hydrocyclones, although in practice by sensing the pressure difference between the mixture inlet means and the water outlet means of a pressure vessel. These pressure differentials represent in a particular case the underflow rate of purified water. Alternatively, the flow rate could be measured more directly by means of a flow meter which senses either the mixture inlet flow rate or the underflow outlet flow rate.
The additional water may be from any source, such as adjacent sea water, but is conveniently water that has already been purified by the hydrocyclones and obtained, for example, from a degassing vessel which is used to de- aerate the purified water downstream of the hydrocyclones. An example of a system constucted to operate in accordance with the present invention is illustrated diagrammatically in the accompanying drawing.
As shown, a mixture of gas, oil and water flows from wells 1 into a manifold 2 and is discharged into a three phase separator 3 where partial separation of oil, gas, and water occurs by gravitational settlement. It is usual that
the pressure within the three phase separator 3 is controlled by controlling the rate at which gas is expelled from the three phase separator. This is achieved by using a pressure controller 4 which senses the pressure in the three phase separator 3 and sends a signal to a control valve 5 so that an opening in the control valve 5 is adjusted to control the gas flow rate through this valve to maintain the pressure in the three phase separator 3 substantially constant at a predetermined value (set point) . Oil is discharged from the three phase separator 3 through a pipe 6.
Water, which may have some oil dispersed within it, is discharged from the three phase separator 3 through a pipe 8 which connects within a bank of hydrocyclones 9, in this case contained within a pressure vessel. At least some of the oil in the water being fed into the hydrocyclones 9 is separated into a discharge stream from the hydrocyclones 9 which is relatively rich in oil. This stream flows through a pipe 10. The other discharge stream from the hydrocyclones 9 flows through a pipe 11 and is at least substantially decontaminated of oil, i.e. this stream consists of purified water.
Due to the fact that oil is less dense than water, the water exists as a layer situated below the oil in the three phase separator 3. Consequently there is an interface between the water and oil layers in the three phase separator 3 where the bottom of the oil layer is in contact with the top of the water layer. There is a level control means 7 which detects the elevation of this oil/water interface. The elevation of the oil/water interface may be adjusted by altering the rate at which water is discharged through the pipe 8 from three phase separator 3.
This is achieved by level control means 7 sending a control signal to adjust an opening of a valve 12 to adjust the flow rate of water through the valve 12 such that the oil/water interface in the three phase separator 3 is
maintained substantially constant at a predetermined value (set point) .
After passing through the control valve 12 the water then enters a degassing vessel 13. Owing to the fact that the pressure in the degassing vessel 13 is appreciably less than the pressure in the three phase separator 3, there may be a substantial quantity of gas associated with the water at the degassing vessel 13. This gas was previously dissolved in the water at the higher pressure experienced at the three phase separator 3.
There exists two layers in the degassing vessel 13, these being a gas layer which is located above a water layer. The elevation of the interface in the degassing vessel 13 is controlled by a level controller 18 and a control valve 17. Water is discharged from the degassing vessel 13 into a pipe 16. At least some of this water may flow through the control valve 17 and subsequently be discharged to the environment e.g. the sea at a location 29. When a hydrocyclone is operating, a pressure drop occurs between the hydrocyclone inlet and the hydrocyclone outlet for purified water. This pressure drop may increase as the flow rate through the hydrocyclone increases.
There is a certain drop corresponding to the minimum flow rate through a hydrocyclone at which efficient separation occurs. A differential pressure controller 24 has a sensing line 26 which detects the pressure upstream of the group of hydrocyclones 9, and another sensing line 25 which detects the pressure of the purified water discharged from the hydrocyclones. The differential pressure controller 24 detects the pressure difference between the line 25 and 26 and sends a signal to a control valve 23. The differential pressure controller 24 has a particular set point. This set point corresponds to a differential pressure at which efficient separation by the hydrocyclones 9 will occur, for example, this set point may correspond to a differential pressure at which the
hydrocyclones 9 may be operating at the minimum flow rate for each hydrocyclone at * , ich efficient separation occurs. A pump 19 has the capability of transferring water from the pipe 16 to the pipe 8 located upstream of the hydrocyclones 9. The extent of opening of the control valve 23 is controlled by the differential pressure controller 24 with the objective of maintaining the differential pressure beween the sensing line 26 and the sensing line 25 at or close to the set point. When the flow rate of water flowing from the three phase separator 3 is substantial and sufficient alone to maintain the hydrocyclones 9 above the minimum flow rate for efficient separation, the differential pressure sensed by differential pressure controller 24 may be larger than the set point. In this circumstance, the differential pressure controller 24 may cause control valve 23 to close. The pump 19 may receive water from a pipe 28 which may receive water from the pipe 16. The pump 19 causes an increase in water pressure, such that the pressure in a pipe 22 at the discharge side of the pump 19 is greater than the pressure in a pipe 28 on the suction side of the pump 19. There is a recycle line adjacent to the pump 19 such that at least some of the water discharged by the pump 19 may return to the suction side of the pump 19 after passing through a control valve 21, which, in conjunction with a pressure controller 20, is used to control the pressure in the pipe 22. The pressure controller 20 senses the pressure in the pipe 22 and sends a signal to the control valve 21 to maintain the pressure in pipe 22 at a particular set point. The flow rate of water from the pipe 22 to a pipe 27 is controlled by the differential pressure control valve 23.
Claims
1. A method of operating a system for de-oiling water, utilising hydrocyclone separators (9) each having a mixture inlet, an overflow oil outlet (10) and an underflow water outlet (11) , wherein the flow through at least one hydrocyclone (9) is sensed, and if the flow approaches a threshold below which there is insufficient flow through the respective hydrocyclone(s) (9) for satisfactory operation, an additional supply or water is fed to the mixture inlet(s) to maintain the flow safely above the threshold.
2. A method according to claim 1, applied to a plurality of banks of the hydrocyclones (9) , each bank acting in parallel and having mixture inlet means leading to the mixture inlets of the hydrocyclones of the respective bank, an outlet means (10) leading from the overflow oil outlets of the hydrocyclones of the respective bank, and water outlet means (11) leading from the underflow water outlets of the hydrocyclones of the respective bank, wherein the flow through the bank of hydrocyclones is sensed and the additional supply of water is fed to the mixture inlet means to maintain the flow safely above the threshold through the hydrocyclones of the respective bank.
3. A method according to claim 1 or claim 2, in which the sensing is carried out indirectly by sensing the pressure difference between the mixture inlet(s) and underflow water outlet(s) (11) of the hydrocyclone(s) (9) .
4. A method according to claims 2 and 3, wherein each of the banks of hydrocyclones (9) is mounted in a respective pressure vessel and the sensing is carried out by sensing the pressure difference between the mixture inlet means and the water outlet means of the pressure vessels.
5, A method according to any one of the preceding claims, in which the additional water is water that has already been purified by the hydrocyclones.
6. A method according to claim 5, in which the additional water is obtained from a degassing vessel (13) which is used to deaerate the purified water downstream of the hydrocyclones (9) .
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP91905136A EP0516715B1 (en) | 1990-03-02 | 1991-02-28 | Improvements relating to hydrocyclone systems |
DE69114125T DE69114125T2 (en) | 1990-03-02 | 1991-02-28 | HYDROCYCLONE SYSTEM. |
US07/923,912 US5507955A (en) | 1990-03-02 | 1991-02-28 | Method of operating hydrocyclone systems by adding water to maintain flow rates |
NO923344A NO303208B1 (en) | 1990-03-02 | 1992-08-27 | Procedure for operating an oil removal plant |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB909004714A GB9004714D0 (en) | 1990-03-02 | 1990-03-02 | Improvements relating to hydrocyclone systems |
GB9004714.3 | 1990-03-02 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991012893A1 true WO1991012893A1 (en) | 1991-09-05 |
Family
ID=10671898
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1991/000309 WO1991012893A1 (en) | 1990-03-02 | 1991-02-28 | Improvements relating to hydrocyclone systems |
Country Status (8)
Country | Link |
---|---|
US (1) | US5507955A (en) |
EP (1) | EP0516715B1 (en) |
AT (1) | ATE129438T1 (en) |
DE (1) | DE69114125T2 (en) |
DK (1) | DK0516715T3 (en) |
GB (1) | GB9004714D0 (en) |
NO (1) | NO303208B1 (en) |
WO (1) | WO1991012893A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2883586A1 (en) * | 2013-12-16 | 2015-06-17 | National Oilwell Varco, L.P. | A fluid treatment system, a fluid processing apparatus and a method of treating a mixture |
US9975063B2 (en) | 2016-07-29 | 2018-05-22 | National Oilwell Varco, L.P. | Apparatus, system, and method for separating oil from a fluid mixture |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5961841A (en) * | 1996-12-19 | 1999-10-05 | Camco International Inc. | Downhole fluid separation system |
US6033577A (en) * | 1998-05-18 | 2000-03-07 | Dravo Lime Company | Coordination of liquid-solid separators and fluid tanks |
SE529452C2 (en) * | 2006-11-02 | 2007-08-14 | Alfa Laval Corp Ab | Separation method for fluid in liquid state comprising of two non-mutually miscible liquids e.g. mineral oil, water, with different densities, to cleanse one liquid from other, uses valve to conduct fluid after centrifugal separation |
GB2490346A (en) | 2011-04-27 | 2012-10-31 | Dps Bristol Holdings Ltd | Cyclonic separator having a tapered core element |
EP2883587B1 (en) * | 2013-12-16 | 2017-09-20 | National Oilwell Varco, LP | A fluid treatment system, a fluid processing apparatus and a method of treating a mixture |
GB201600456D0 (en) * | 2016-01-11 | 2016-02-24 | Statoil Petroleum As | Process |
CN111573998B (en) * | 2020-06-12 | 2023-07-11 | 浙江大学 | High-efficient anaerobic water-out degasification removes calcium system of waste paper papermaking waste water |
US11639656B1 (en) * | 2022-08-19 | 2023-05-02 | Total Gas Resource Recovery, Llc | Natural gas capture from a well stream |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1985000851A1 (en) * | 1983-08-04 | 1985-02-28 | Noel Carroll | Oil recovery systems |
EP0160629A2 (en) * | 1984-04-26 | 1985-11-06 | WIKDAHL, Nils Anders Lennart | A method and system for controlling the apex flow of a multihydrocyclone for fiber suspensions |
WO1987001968A1 (en) * | 1985-10-02 | 1987-04-09 | Carroll, Noel | Treatment of multi-phase mixtures |
WO1989004725A1 (en) * | 1987-11-19 | 1989-06-01 | Noel Carroll | Method and apparatus for separating phases of a multi-phase liquid |
US4844812A (en) * | 1988-06-22 | 1989-07-04 | Amoco Corporation | Pumped hydrocyclone backpressure control |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4464264A (en) * | 1982-03-04 | 1984-08-07 | Noel Carroll | Cyclone separator |
FI65864C (en) * | 1982-10-06 | 1984-07-10 | Veera Kaihdin Ky | REKLAMGARDIN |
WO1984004702A1 (en) * | 1983-06-01 | 1984-12-06 | Noel Carroll | Overflow outlet for a cyclone separator |
GB2150467A (en) * | 1983-06-01 | 1985-07-03 | Noel Carroll | Liquid separating apparatus |
US4737287A (en) * | 1984-07-19 | 1988-04-12 | Noel Carroll | Fluid flow apparatus |
US4844817A (en) * | 1988-06-29 | 1989-07-04 | Conoco Inc. | Low pressure hydrocyclone separator |
-
1990
- 1990-03-02 GB GB909004714A patent/GB9004714D0/en active Pending
-
1991
- 1991-02-28 AT AT91905136T patent/ATE129438T1/en not_active IP Right Cessation
- 1991-02-28 DK DK91905136.7T patent/DK0516715T3/en active
- 1991-02-28 US US07/923,912 patent/US5507955A/en not_active Expired - Fee Related
- 1991-02-28 WO PCT/GB1991/000309 patent/WO1991012893A1/en active IP Right Grant
- 1991-02-28 DE DE69114125T patent/DE69114125T2/en not_active Expired - Fee Related
- 1991-02-28 EP EP91905136A patent/EP0516715B1/en not_active Expired - Lifetime
-
1992
- 1992-08-27 NO NO923344A patent/NO303208B1/en unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1985000851A1 (en) * | 1983-08-04 | 1985-02-28 | Noel Carroll | Oil recovery systems |
EP0160629A2 (en) * | 1984-04-26 | 1985-11-06 | WIKDAHL, Nils Anders Lennart | A method and system for controlling the apex flow of a multihydrocyclone for fiber suspensions |
WO1987001968A1 (en) * | 1985-10-02 | 1987-04-09 | Carroll, Noel | Treatment of multi-phase mixtures |
WO1989004725A1 (en) * | 1987-11-19 | 1989-06-01 | Noel Carroll | Method and apparatus for separating phases of a multi-phase liquid |
US4844812A (en) * | 1988-06-22 | 1989-07-04 | Amoco Corporation | Pumped hydrocyclone backpressure control |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2883586A1 (en) * | 2013-12-16 | 2015-06-17 | National Oilwell Varco, L.P. | A fluid treatment system, a fluid processing apparatus and a method of treating a mixture |
WO2015090967A1 (en) * | 2013-12-16 | 2015-06-25 | National Oilwell Varco, Lp | A fluid treatment system, a fluid processing apparatus and a method of treating a mixture |
US9975063B2 (en) | 2016-07-29 | 2018-05-22 | National Oilwell Varco, L.P. | Apparatus, system, and method for separating oil from a fluid mixture |
Also Published As
Publication number | Publication date |
---|---|
EP0516715A1 (en) | 1992-12-09 |
EP0516715B1 (en) | 1995-10-25 |
DE69114125T2 (en) | 1996-06-20 |
US5507955A (en) | 1996-04-16 |
GB9004714D0 (en) | 1990-04-25 |
DE69114125D1 (en) | 1995-11-30 |
NO923344D0 (en) | 1992-08-27 |
DK0516715T3 (en) | 1996-02-05 |
NO303208B1 (en) | 1998-06-15 |
NO923344L (en) | 1992-08-27 |
ATE129438T1 (en) | 1995-11-15 |
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