US3797200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of methane and nitrogen mixtures under non-steadystate conditions
Assignee: Northern Natural Gas Co
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Filing: 1973-02-12
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Granted: 1974-03-19
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Expires: 1993-02-12
Abstract
Abstract A gas mixture of methane and nitrogen is separated into enriched components under non-steady state conditions wherein nitrogen in the mixture is picked up more favorably by a membrane which is a homopolymer of acrylonitrile, such nitrogen being picked up before the concentration composition of the permeated or absorbed gases reach substantially constant levels.
Inventors
- 👤 D Klass
- 👤 C Landahl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:27
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/22; B01D53/228
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
38 words
A method as in claim 1 wherein said gas permeable membrane system is an endless film so that a given point in said film is continuously recycled through respective sorption and desorption zone during said non-steady state conditions.
Claim 2
Dependent Claim
39 words
A method as in claim 1 wherein said gas permeable membrane system is a supported membrane sheet which reciprocates between adjoining sorption and desorption zones at predetermined velocities and pauses in the respective zone during said non-steady state conditions.
Claim 3
Dependent Claim
58 words
A method which includes the steps of claim 1 wherein said membrane is moved into a desorption zone, and wherein a point on said moved membrane is retained during movement in said desorption zone for a time sufficient for the nitrogen component carried by said membrane to be substantially collected in said desorption zone as an enriched component.
Claim 4
Dependent Claim
22 words
A method as in claim 1 above wherein said relative movement is effected by moving the permeable membrane at a predetermined velocity.
References Cited (Backward Citations)
US3398504A
Cited
US3616607A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |