US4260489A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of oily sludge
Assignee: BP PLC
•
Filing: 1979-07-19
•
Granted: 1981-04-07
•
Expires: 1999-07-19
Abstract
Abstract Oily sludge is treated by filtering it through a precoated surface filter, treating the filtration residue with a hydrocarbon solvent and/or steam stripping the extracted residue. The residual oil content of the treated sludge is very low and it can be used for land fill operations.
Inventors
- 👤 George Greig
- 👤 Michael P. Broadribb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:27
CPC Classifications
B; B01; B01D; B01D11/00; B01D11/02; B01D11/0288; B01D37/00; B01D37/02
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
119 words
A method for the treatment of oily sludge having a water content in the range of 20-95% by weight, an oil content in the range 5-70% by weight and the remainder solid particles, which method comprises the steps of diluting the oily sludge with water only, filtering the water-diluted oily sludge in a precoated surface filter to produce a filter cake comprising mainly said solid particles together with some oil and water, washing the filter cake while on the filter with a light hydrocarbon solvent selected from the group consisting of kerosene and naphtha to remove the oil and water, and steam stripping the washed filter cake to a residual oil content of less than 1% by weight oil.
Claim 2
Independent Claim
119 words
A method for the treatment of oily sludge having a water content in the range of 20-95% by weight, an oil content in the range 5-70% by weight and the remainder solid particles, which method comprises the steps of diluting the oily sludge with water only, filtering the water-diluted oily sludge in a precoated surface filter to produce a filter cake comprising mainly said solid particles together with some oil and water, washing the filter cake while on the filter with a light hydrocarbon solvent selected from the group consisting of kerosene and naphtha to remove the oil and water, and steam stripping the washed filter cake to a residual oil content of less than 1% by weight oil.
Claim 3
Dependent Claim
13 words
A method according to claim 1 wherein the pre-coat material is diatomaceous earth.
Claim 4
Independent Claim
18 words
A method according to claims 1 or 2 wherein the surface filter is a plate or candle filter.
Claim 5
Dependent Claim
15 words
A method according to claim 1 or 2 wherein the filter is operated under pressure.
Claim 6
Independent Claim
13 words
A method according to claims 1 or 2 wherein the solvent is kerosene.
Claim 7
Independent Claim
13 words
A method according to claims 1 or 2 wherein the solvent is heated.
Claim 8
Independent Claim
37 words
A method according to claims 1 or 2 wherein the solvent washing is carried out in two stages with solvent from the second stage of one cycle being used in the first stage of the next cycle.
Claim 9
Independent Claim
20 words
A method according to claims 1 or 2 wherein a filter aid is added to the oily sludge before filtration.
Claim 10
Dependent Claim
13 words
A method according to claim 8 wherein the filter aid is diatomaceous earth.
Claim 11
Independent Claim
20 words
A method according to claims 1 or 2 wherein a drying stage is interposed after filtration and before solvent washing.
Claim 12
Independent Claim
23 words
A method according to claims 1 or 2 wherein the filtration flowrate is in the range of 0.05-10 m 3 /m 2 /hr.
Claim 13
Dependent Claim
21 words
A method according to claim 11 wherein the filtration flowrate is in the range of 0.5-2.5 m 3 /m 2 /hr.
Claim 14
Independent Claim
23 words
A method according to claims 1 or 2 wherein solid filter cake material is removed from the filter by scraping or centrifugal action.
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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) | 1984-04-06 | 1984-10-06 | 1985-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-04-06 | 1988-10-06 | 1989-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-04-06 | 1992-10-06 | 1993-04-07 | $7700.00 | Window Closed / Lapsed |