US 5,240,473 AGranted

Process for restoring permeance of an oxygen-permeable ion transport membrane utilized to recover oxygen from an oxygen-containing gaseous mixture

AssigneeAir Products and Chemicals, Inc.

InventorsMichael F. Carolan, Paul N. Dyer, James M. LaBar, Sr., Robert M. Thorogood

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Abstract

This invention relates to a process for restoring permeance of an oxygen-permeable ion transport membrane utilized to recover oxygen from an oxygen-containing gaseous mixture which contains water, carbon dioxide or volatile hydrocarbons. The process utilizes a class of ion transport membranes formed from multicomponent metallic oxides wherein permeance of such membranes had been believed to be permanently degraded by water and the like under conventional process operating temperatures. This invention provides a continuous process for restoring oxygen permeance of such membranes caused by deleterious interaction between the membrane and components such as carbon dioxide, water or hydrocarbons at elevated process temperatures.

Claims25

Dependent claims

A process for restoring permeance of an ion transport membrane utilized to recover oxygen from an oxygen-containing gaseous mixture containing one or more components selected from water, carbon dioxide or a volatile hydrocarbon, the process which comprises the steps of:

(a) delivering the oxygen-containing gaseous mixture into a first gas compartment which is separated from a second gas compartment by an ion transport membrane comprising a multicomponent metallic oxide;
(b) establishing a positive oxygen partial pressure difference between the first and second gas compartments by producing an excess oxygen partial pressure in the first gas compartment and/or by producing a reduced oxygen partial pressure in the second gas compartment;
(c) contacting the oxygen-containing gaseous mixture with the ion transport membrane at a process temperature ranging from 650.degree. C. to 800.degree. C. to separate the oxygen-containing gaseous mixture into an oxygen permeate stream and an oxygen-depleted gaseous stream and recovering the oxygen permeate stream until such time as the permeance drops to a predetermined value;
(d) raising the process temperature to a temperature greater than about 810.degree. C. for a period of time sufficient to restore membrane permeance to a second predetermined value;
and
(e) repeating steps (c) and (d).

3 more elements

A process for recovering oxygen from an oxygen-containing gaseous mixture containing one or more components selected from water, carbon dioxide or a volatile hydrocarbon, the process which comprises the steps of:

(a) delivering the oxygen-containing gaseous mixture into a first gas compartment which is separated from a second gas compartment by an ion transport membrane comprising a multicomponent metallic oxide represented by A.sub.x A'.sub.x' A".sub.x" B.sub.y B'.sub.y' B".sub.y" O.sub.3-z, where A and A" are independently selected from the group consisting of the elements of Groups 1, 2 and 3 and the F block lanthanides;
A' is selected from calcium, barium, strontium or magnesium and B, B' and B" are chosen from the D block transition metals according to the Periodic Table of the Elements adopted by the IUPAC wherein 0.ltoreq.x".ltoreq.1, 0<x'.ltoreq.1, 0.ltoreq.x.ltoreq.1, 0<y.ltoreq.1, 0.ltoreq.y'.ltoreq.1, 0.ltoreq.y".ltoreq.1, x+x'+x"=1, y+y'+y"=1 and z is a number which renders the composition charge neutral;
(b) establishing a positive oxygen partial pressure difference between the first and second gas compartments by producing an excess oxygen partial pressure in the first gas compartment and/or by producing a reduced oxygen partial pressure in the second gas compartment;
(c) contacting the oxygen-containing gaseous mixture with the ion transport membrane at a temperature less than about 810.degree. C. to separate the oxygen-containing gaseous mixture into an oxygen permeate stream and an oxygen-depleted gaseous stream and recovering the oxygen permeate stream until such time as the permeance drops to a predetermined value;
(d) raising the process temperature to a temperature greater than about 810.degree. C. for a period of time sufficient to restore membrane permeance to a second predetermined value;
and
(e) repeating steps (c) and (d).

4 more elements

Dependencies are inferred from the claim text.