US3779028A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Improved krypton xenon recovery method
Assignee: BOC Group Ltd
•
Filing: 1971-10-08
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Granted: 1973-12-18
•
Expires: 1991-10-08
Abstract
Abstract Krypton and xenon are recovered from the oxygen produced in the reboiler of an air separation unit by passing the oxygen into a two-section rectification column having at least one reboiler and in which the reflux ratio is selected to give a primary krypton/xenon concentrate of low methane content and containing at least 10 percent krypton.
Inventors
- 👤 P Schuftan
- 👤 G Davis
- 👤 J Armond
- 👤 J Leader
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:45
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/04; F25J3/04151; F25J3/04187; F25J3/04218; F25J3/04224; F25J3/04248; F25J3/04284; F25J3/0429; F25J3/04303; F25J3/04333; F25J3/04363; F25J3/04406; F25J3/04412; F25J3/04642; F25J3/04745; F25J2200/00; F25J2200/34; F25J2200/40; F25J2200/76; F25J2205/00; F25J2205/60; F25J2220/00; F25J2220/52; F25J2235/00; F25J2235/50; Y; Y10; Y10S; Y10S62/00; Y10S62/923; Y10S62/925
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
25 words
A process as claimed in claim 1, wherein any residual acetylene is removed by an adsorber located in the lower section of the rectification column.
Claim 2
Dependent Claim
25 words
A process as claimed in claim 2, wherein an additional reboiler is provided at an intermediate point in the lower section of the rectification column.
Claim 3
Dependent Claim
20 words
A process as claimed in claim 1 , wherein the reflux ratio is maintained within the range of about 10:1.
Claim 4
Dependent Claim
64 words
A process as claimed in claim 1, wherein a small portion of the liquid oxygen from the reboiler of the air separation column is added to the reflux liquid leaving the upper section of the rectification column so as to balance the cold losses of the rectification column and to prevent the accumulation of heavy hydrocarbons in the reboiler of the air separation column.
Claim 5
Dependent Claim
44 words
A process as claimed in claim 1, wherein the reboil in the rectification column is provided by condensing gaseous oxygen, the liquid oxygen thus obtained being introduced into the upper part of the upper section of the rectification column to act as the reflux.
Claim 6
Dependent Claim
39 words
A process as claimed in claim 6, wherein the gaseous oxygen feeding to the rectification column reboiler is a portion of the gaseous oxygen withdrawn from the top of the rectification column and after compression recycled into the reboiler.
Claim 7
Dependent Claim
29 words
A process as claimed in claim 1 wherein the reboil in the rectification column is provided by condensing air or nitrogen and providing a condenser in the rectification column.
Claim 8
Dependent Claim
32 words
A process as claimed in claim 6, wherein the reflux ratio is adjusted by providing a valve in the line supplying the reflux liquid to the upper part of the upper section.
Claim 9
Dependent Claim
34 words
A process as claimed in claim 9, wherein the valve is automatically controlled by a ratio controller between a flowmeter in the reflux supply line and a flowmeter in the gaseous oxygen withdrawal line.
Claim 10
Dependent Claim
22 words
A process as claimed in claim 1, wherein oxygen and residual hydrocarbons are removed from the crude concentrate by a hydrogen blowpipe.
Claim 11
Dependent Claim
44 words
A process as claimed in claim 1 wherein residual hydrocarbons contained in the crude primary concentrate are catalytically oxidised by copper oxide and oxygen is subsequently removed by reaction with manganous oxide, and the resulting gas mixture is dried and freed from carbon dioxide.
Claim 12
Dependent Claim
44 words
A process as claimed in claim 1, wherein oxygen and residual hydrocarbons are removed from the crude concentrate to yield a product that is then condensed and fractionally vaporised at about 1 bar, the vapour formed being passed at about 120*K through an adsorbent.
Claim 13
Dependent Claim
18 words
A process as claimed in claim 1, wherein the crude primary krypton/xenon concentrate contains about 60 percent krypton.
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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) | 1976-12-17 | 1977-06-18 | 1977-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-17 | 1981-06-18 | 1981-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-17 | 1985-06-18 | 1985-12-18 | $7700.00 | Window Closed / Lapsed |