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US RE34,595 EGranted
Process for removing oxygen and nitrogen from crude argon
AssigneeAir Products and Chemicals, Inc.
InventorsMichael S. K. Chen, Philip J. Cook
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AssigneeAir Products and Chemicals, Inc.
InventorsMichael S. K. Chen, Philip J. Cook
Estimating the term…
[A process is provided for purifying argon gas, especially an argon gas stream obtained by cryogenically separating air, wherein the argon gas is heated and compressed, and then permeated through a solid electrolyte membrane selective to the permeation of oxygen over other components of the gas, and removing oxygen from the argon by selective permeation of oxygen through the membrane. The purified argon can then be distilled to remove other components such as nitrogen.] A process is provided for producing a purified argon stream wherein oxygen and nitrogen are removed from crude bulk argon streams, particularly those produced by cryogenic, adsorptive or membrane separation of air. The process comprises separating a heated, compressed crude argon stream containing nitrogen and oxygen into an oxygen permeate stream and an oxygen-depleted argon stream by passing the compressed heated argon stream through a solid electrolyte membrane selective to the permeation of oxygen. The oxygen-depleted argon stream is then fed to a distillation column to separate nitrogen from the oxygen-depleted argon stream to form the purified argon stream and a nitrogen waste stream.
[1. A process for purifying bulk argon which comprises recovering a crude bulk argon gas containing oxygen from a cryogenic, adsorptive or membrane separation of air, heating the crude argon gas to a temperature of from about 450.degree. to 800.degree. C. and comprising the crude argon gas to a pressure of about 30 to 80 psig, feeding the heated, compressed gas to a high temperature solid electrolyte membrane selective to the permeation of oxygen over other components of the gas, and separating oxygen from the argon gas by selective permeation of oxygen through the membrane.]
[2. The process of claim 1 wherein the oxygen in the argon gas stream is reduced to less than about 1 ppm.]
[3. The process of claim 2 wherein the oxygen gas is permeated through two or more membranes.]
[4. The process of claim 1 wherein the membrane is made of mixed conductors with mixed conductivity for oxygen ions and electrons.]
[5. The process of claim 4 wherein the oxygen is permeated through a doped zirconia membrane.]
[6. The process of claim
[7. The process of claim 4 wherein the oxygen is permeated through a doped bismuth oxide membrane.]
[8. The process of claim 7 wherein the membrane is doped with yttrium oxide.]
[9. The process of claim 1 wherein a sweep gas is used to lower permeate oxygen pressure.]
[10. The process of claim 1 which comprises feeding the argon gas from the membrane to a distillation column to separate argon from any other components of the gas.]
[11. The process of claim 10 wherein nitrogen is separated from argon in the distillation column.]
[12. The process of claim 1 which comprises subjecting the argon gas from the membrane to hydrogen deoxidation.]
[13. The process of claim 12 which comprises feeding the argon gas from the hydrogen deoxidation to a distillation column to separate argon from any other components of the gas.]
[14. The process of claim 13 wherein nitrogen is separated from argon in the distillation column.]
A process for removing oxygen and nitrogen from a crude argon stream comprising the steps of:
The process according to claim 18 wherein the solid electrolyte membrane consists of a mixed conductor. 0. The process according to claim 19 wherein the mixed conductor demonstrates an oxygen ionic conductivity ranging from 0.01 to 1 ohm.sup.-1 cm.sup.-1 and an electronic conductivity ranging from about 1 to 30 ohm.sup.-1 cm.sup.-1.
The process according to claim 20 wherein the mixed conductor is an oxide selected from the group consisting of the oxides of Co-Sr-Bi, Co-La-Bi, Co-Sr-Ce and Co-La-Ce.
The process of claim 23 wherein the solid electrolyte material is selected from the group consisting of doped zirconium oxide and doped bismuth oxide. 25. The process of claim 24 wherein the solid electrolyte material is doped with an oxide selected from the group consisting of the oxides of yttria, calcia and baria.
A process for removing oxygen and nitrogen from a crude argon stream comprising the steps of:
Dependencies are inferred from the claim text.