Patent US4889638A successfully refreshed from Google Patents.
US4889638A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Agitation and/or gas separation and dispersed gas flotation
Assignee: BTR Industries Ltd
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Filing: 1988-08-12
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Granted: 1989-12-26
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Expires: 2008-08-12
Abstract
Abstract A method of, and apparatus for, separating phases in a polyphase system is described and particularly in separating oil from produced water by the contact of gas bubbles and oil droplets by a dispersed gas flotation technique. A polyphase system is divided into at least two portions. The pressure of one portion is reduced to form bubbles of a gas, and the two portions are then recombined whereby the bubbles in the mixture enhances flotation, and hence separation of the dispensed phase, e.g. oil, from the continuous phase, e.g. water. The invention has particular application in the oil industry and in other fields where efficient separation is required.
Inventors
- 👤 David B. Rockford
- 👤 William H. Sutton
- 👤 Christopher R. Bond
- 👤 Brian Wilkinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:25
CPC Classifications
B; B03; B03D; B03D1/00; B03D1/14; B03D1/1431; B01; B01D; B01D17/00; B01D17/02; B01D17/0205; B03D1/02; B03D1/028; B03D1/1412; E; E21; E21B; E21B43/00; E21B43/34
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
196 words
A method for the gas flotation treatment of a produced water mixture including oil and water to reduce the oil content of the water, the mixture being continuously produced under a relatively high pressure and having a gas naturally present in solution, said method comprising the steps of: carrying the mixture from a first vessel at said relatively high pressure in first pipe means to a flotation vessel at a relatively low pressure by way of first controllable pressure letdown means arranged in the first pipe means; selectively operating the first controllable pressure letdown means to transfer mixture from said first vessel to said flotation vessel according to a rate of production of said mixture; providing second pipe means having second controllable pressure letdown means, said second pipe means extending from an influent location upstream of the first controllable pressure letdown means to a discharge location in communication with the flotation vessel; and selectively operating said second controllable pressure letdown means to establish at said discharge location a flow of mixture laden with bubbles of said naturally present gas released from solution and caused by cavitation for gas flotation treatment of mixture in the flotation vessel.
Claim 2
Independent Claim
196 words
A method for the gas flotation treatment of a produced water mixture including oil and water to reduce the oil content of the water, the mixture being continuously produced under a relatively high pressure and having a gas naturally present in solution, said method comprising the steps of: carrying the mixture from a first vessel at said relatively high pressure in first pipe means to a flotation vessel at a relatively low pressure by way of first controllable pressure letdown means arranged in the first pipe means; selectively operating the first controllable pressure letdown means to transfer mixture from said first vessel to said flotation vessel according to a rate of production of said mixture; providing second pipe means having second controllable pressure letdown means, said second pipe means extending from an influent location upstream of the first controllable pressure letdown means to a discharge location in communication with the flotation vessel; and selectively operating said second controllable pressure letdown means to establish at said discharge location a flow of mixture laden with bubbles of said naturally present gas released from solution and caused by cavitation for gas flotation treatment of mixture in the flotation vessel.
Claim 3
Dependent Claim
48 words
The method claimed in claim 1, wherein the selective operation of the first and second controllable pressure letdown means is such that the mean flow rate of mixture in said second pipe means is between 1% and 50% of the mean flow rate in said first pipe means.
Claim 4
Dependent Claim
18 words
The method claimed in claim 2, wherein said second controllable pressure letdown means comprises multi-stage pressure letdown means.
Claim 5
Dependent Claim
18 words
The method claimed in claim 2, wherein said second controllable pressure letdown means comprises gas bubble shearing means.
Claim 6
Dependent Claim
91 words
The method claimed in claim 2, wherein the said step of selectively operating said second controllable pressure letdown means is a multi-stage operation, in which the mixture flow in said second pipe means is subjected upstream of the said discharge location to a primary pressure letdown to an intermediate pressure at which bubbles form in the mixture due to said naturally present gas breaking from solution, and at said discharge location the mixture and bubbles therein are subjected to a final pressure letdown to the ambient pressure of the flotation vessel.
Claim 7
Dependent Claim
30 words
The method of claim 5 wherein between said primary pressure letdown and said discharge location the bubbles formed at the primary pressure letdown stage are sheared to reduce their size.
Claim 8
Independent Claim
140 words
A method for the treatment of a produced water mixture including oil and water to reduce the oil content of the water, the mixture being continuously produced under a relatively high pressure and having a gas naturally present in solution, to reduce the oil content thereof, comprising the steps of: dividing the produced water mixture into first and second portions; modifying the first portion by reducing the pressure thereof in a single stage; delivering the modified first portion to a flotation vessel; modifying the said second portion by reducing the pressure thereof to effect a controlled formation of gas bubbles therein of a desired mean size, said gas bubbles being released from solution and caused by cavitation; and injecting the modified second portion into the flotation vessel to effect gas flotation treatment of the combined first and second modified portions.
Claim 9
Independent Claim
140 words
A method for the treatment of a produced water mixture including oil and water to reduce the oil content of the water, the mixture being continuously produced under a relatively high pressure and having a gas naturally present in solution, to reduce the oil content thereof, comprising the steps of: dividing the produced water mixture into first and second portions; modifying the first portion by reducing the pressure thereof in a single stage; delivering the modified first portion to a flotation vessel; modifying the said second portion by reducing the pressure thereof to effect a controlled formation of gas bubbles therein of a desired mean size, said gas bubbles being released from solution and caused by cavitation; and injecting the modified second portion into the flotation vessel to effect gas flotation treatment of the combined first and second modified portions.
Claim 10
Dependent Claim
35 words
The method claimed in claim 7, wherein the step modifying the said second portion of the produced water mixture is carried out by reducing the pressure thereof over at least two stages of pressure reduction.
Claim 11
Dependent Claim
21 words
The method claimed in claim 8, wherein one of said last mentioned stages of pressure reduction comprises a bubble shearing operation.
Claim 12
Dependent Claim
168 words
Apparatus for use in the treatment of a produced water mixture including oil and water to reduce the oil content of the water, the mixture being continuously produced under a relatively high pressure and having a gas naturally present in solution, to reduce the oil content thereof, comprising: a first vessel for holding the produced water mixture under relatively high pressure, a flotation vessel, first pipe means extending between the first vessel and the flotation vessel, first controllable pressure letdown means arranged in said first pipe means, second pipe means extending from an influent location upstream of said first controllable pressure letdown means and on a downsteam side of said first vessel to a discharge location in communication with the flotation vessel, and second controllable pressure letdown means for establishing at said discharge location a flow of mixture laden with bubbles of said naturally present gas from solution and caused by cavitation for gas flotation treatment of mixture in the flotation vessel arranged in said second pipe means.
Claim 13
Dependent Claim
168 words
Apparatus for use in the treatment of a produced water mixture including oil and water to reduce the oil content of the water, the mixture being continuously produced under a relatively high pressure and having a gas naturally present in solution, to reduce the oil content thereof, comprising: a first vessel for holding the produced water mixture under relatively high pressure, a flotation vessel, first pipe means extending between the first vessel and the flotation vessel, first controllable pressure letdown means arranged in said first pipe means, second pipe means extending from an influent location upstream of said first controllable pressure letdown means and on a downsteam side of said first vessel to a discharge location in communication with the flotation vessel, and second controllable pressure letdown means for establishing at said discharge location a flow of mixture laden with bubbles of said naturally present gas from solution and caused by cavitation for gas flotation treatment of mixture in the flotation vessel arranged in said second pipe means.
Claim 14
Dependent Claim
30 words
Apparatus as claimed in claim 10, wherein the first controllable pressure letdown means is a valve means operable to control the level of produced water mixture in said first vessel.
Claim 15
Dependent Claim
43 words
Apparatus as claimed in claim 10, wherein the second controllable pressure letdown means comprises a primary pressure letdown valve arranged in the second pipe means upstream of said discharge location, and a final pressure letdown valve arranged downstream of the said primary valve.
Claim 16
Dependent Claim
17 words
Apparatus as claimed in claim 12, wherein the final letdown valve is disposed adjacent said discharge location.
Claim 17
Dependent Claim
25 words
The apparatus of claim 12 wherein gas bubble shearing means are arranged in said second pipe means between said primary and said final letdown valves.
Claim 18
Dependent Claim
15 words
The apparatus of claim 13 wherein said discharge location is disposed within said flotation vessel.
Claim 19
Dependent Claim
15 words
The method of claim 1 wherein said discharge location is disposed with said flotation vessel.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-25 | 1993-06-26 | 1993-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-25 | 1997-06-26 | 1997-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-25 | 2001-06-26 | 2001-12-26 | $7700.00 | Window Closed / Lapsed |