US4057407A
Expired / Lapsed
US
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Method and apparatus for recovering argon from an air fractionating process
Assignee: SIAD Societa Italiana Acetilene e Derivati SpA
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Filing: 1976-03-22
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Granted: 1977-11-08
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Expires: 1996-03-22
Abstract
Abstract A method for the purification of argon in a gas obtained as a by-product from the fractionation of air to the recover O 2 and N 2 is described. The argon-containing gas is fed to a single argon-rectifying column which separates oxygen and then to a conventional purification column in which the separation takes place. The apparatus for carrying out the method comprises a rectification column having the top connected to a heating compressing and cooling circuit for liquefying and recycling in the liquid state the evolved vapors; the bottom of the column is heated by a fraction of the compressed but not cooled gaseous mixture drawn from the heating and compressing section of said circuit; the end section of this latter being further connected to a conventional nitrogen-withdrawing column for feeding a portion of the oxygen-free liquefied product.
Inventors
- 👤 Emanuele Bigi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:32
CPC Classifications
F; F25; F25J; F25J3/00; F25J3/02; F25J3/04; F25J3/04642; F25J3/04648; F25J3/04654; F25J3/04666; F25J3/04248; F25J3/04333; F25J3/04369; F25J3/0466; F25J3/04721; F25J3/04727; Y; Y10; Y10S; Y10S62/00; Y10S62/923; Y10S62/924
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
202 words
A method for producing argon by separation from oxygen and nitrogen from an air fractionation process, characterized in that it comprises the steps of: a. forwarding to a rectifying column a gaseous argon, nitrogen and oxygen containing product coming out from an intermediate point of air fractionation column of said fractionation process; b. heating a gaseous oxygen-free product containing a major amount of argon drawn from the head of said rectifying column; c. compressing the oxygen-free product; d. cooling a first fraction of the compressed product up to the liquefaction temperature of argon according to the compression pressure to form a liquefied product; e. recycling a portion of the liquefied product to the top of said rectifying column through a throttling element to provide the reflux liquid for the rectifying column, the remaining portion of liquefied product being forwarded to the inlet of an argon column for withdrawing nitrogen; f. causing a second fraction of compressed, gaseous oxygen-free product to flow to the bottom of said rectifying column for indirect reboil heat exchange, and g. recycling the second fraction in a partially cooled state, by having transferred calories to the rectification column, for further cooling up to the liquefaction temperature of argon.
Claim 2
Independent Claim
202 words
A method for producing argon by separation from oxygen and nitrogen from an air fractionation process, characterized in that it comprises the steps of: a. forwarding to a rectifying column a gaseous argon, nitrogen and oxygen containing product coming out from an intermediate point of air fractionation column of said fractionation process; b. heating a gaseous oxygen-free product containing a major amount of argon drawn from the head of said rectifying column; c. compressing the oxygen-free product; d. cooling a first fraction of the compressed product up to the liquefaction temperature of argon according to the compression pressure to form a liquefied product; e. recycling a portion of the liquefied product to the top of said rectifying column through a throttling element to provide the reflux liquid for the rectifying column, the remaining portion of liquefied product being forwarded to the inlet of an argon column for withdrawing nitrogen; f. causing a second fraction of compressed, gaseous oxygen-free product to flow to the bottom of said rectifying column for indirect reboil heat exchange, and g. recycling the second fraction in a partially cooled state, by having transferred calories to the rectification column, for further cooling up to the liquefaction temperature of argon.
Claim 3
Dependent Claim
52 words
The method of claim 1 wherein: a liquid product consisting essentially of oxygen is drawn from the base of said rectifying column, the liquid product being then forwarded to the inlet of said air fractionating column in a position near to the drawing point of said gaseous argon, nitrogen and oxygen-containing product.
Claim 4
Dependent Claim
100 words
The method of claim 1 which further comprises: a. passing said first fraction of compressed product through a heat exchange countercurrently to the gaseous oxygen-free head product to heat said head product prior to cooling said first fraction, b. thereafter, reuniting the first fraction with the second fraction of compressed product after the second fraction has passed through the bottom of said rectifying column, and c. passing the reunited fractions through a heat exchange countercurrently to a refrigerating fluid, to cool the compressed product to the liquefaction temperature of argon prior to recycling to the top of the rectifying column.
Claim 5
Dependent Claim
32 words
The method of claim 3 wherein said refrigerating fluid for cooling the fractions to the liquefaction temperature of argon is liquid nitrogen coming from the top portion of said air fractionation column.
Claim 6
Independent Claim
263 words
An apparatus for producing argon by the separation thereof from oxygen and nitrogen in a liquid air fractionation plant, characterized in that said apparatus comprises: a. an air fractionation column, b. a rectifying column having an inlet pipe connected to a middle point of said fractionation column of said fractionation plant for issuing a gaseous nitrogen, oxygen and argon containing product into the bottom of said rectifying column; c. a compressing and cooling circuit for the liquefaction of gaseous product coming out of the head zone of the rectifying column, the circuit including a throttling element for recycling the produced liquid into the head zone of the rectifying column; d. means interconnecting the head zone of the rectifying column and the cooling and compressing circuit such that the gaseous product at the top of the head zone is delivered to the circuit; e. a heat exchange disposed in the bottom of said rectifying column for transferring calories to the bottom zone of the rectifying column, the heat exchanger utilizing a fraction of the gaseous head zone product drawn through the circuit after the compression and before the cooling; f. means for delivering the compressed fraction to the heat exchanger disposed in the bottom of the rectifying column; g. a draining pipeline branching off from said bottom zone of said rectifying column, the pipeline draining the bottoms of the rectifying column, and h. a pipeline being interposed in said circuit between the cooling stage and the throttling element for supplying a fraction of the liquid product to the inlet of an argon-nitrogen separation column.
Claim 7
Independent Claim
263 words
An apparatus for producing argon by the separation thereof from oxygen and nitrogen in a liquid air fractionation plant, characterized in that said apparatus comprises: a. an air fractionation column, b. a rectifying column having an inlet pipe connected to a middle point of said fractionation column of said fractionation plant for issuing a gaseous nitrogen, oxygen and argon containing product into the bottom of said rectifying column; c. a compressing and cooling circuit for the liquefaction of gaseous product coming out of the head zone of the rectifying column, the circuit including a throttling element for recycling the produced liquid into the head zone of the rectifying column; d. means interconnecting the head zone of the rectifying column and the cooling and compressing circuit such that the gaseous product at the top of the head zone is delivered to the circuit; e. a heat exchange disposed in the bottom of said rectifying column for transferring calories to the bottom zone of the rectifying column, the heat exchanger utilizing a fraction of the gaseous head zone product drawn through the circuit after the compression and before the cooling; f. means for delivering the compressed fraction to the heat exchanger disposed in the bottom of the rectifying column; g. a draining pipeline branching off from said bottom zone of said rectifying column, the pipeline draining the bottoms of the rectifying column, and h. a pipeline being interposed in said circuit between the cooling stage and the throttling element for supplying a fraction of the liquid product to the inlet of an argon-nitrogen separation column.
Claim 8
Dependent Claim
40 words
The apparatus of claim 5, wherein said draining pipeline connects the bottom of said rectifying column to the air fractionating column of said air fractionating plant in a position which is near to the outlet point of said inlet pipe.
Claim 9
Dependent Claim
117 words
The apparatus of claim 5 wherein said circuit comprises: a. a compressor, b. a first countercurrent heat exchange in fluid communication with said compressor, c. a second countercurrent heat exchanger in fluid communication with the first countercurrent heat exchanger and the bottom zone heat exchanger, and wherein the compressed gaseous product passing through the first countercurrent heat exchanger passes countercurrent to gaseous product being delivered to the circuit to heat the gaseous product, the second countercurrent heat exchanger utilizes a refrigerating fluid having a temperature lower than that of the liquefaction temperature of argon, the refrigerating fluid passing countercurrently to the compressed gaseous heat exchanger and the compressed gaseous product exiting from the bottom zone heat exchanger.
Claim 10
Dependent Claim
22 words
The apparatus of claim 7, wherein said refrigerating fluid in said heat exchanger is liquid nitrogen drawn from said air fractionation plant.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-11-07 | 1981-05-09 | 1981-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-07 | 1985-05-09 | 1985-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-07 | 1989-05-09 | 1989-11-08 | $7700.00 | Window Closed / Lapsed |