Solid state oxygen anion and electron mediating membrane and catalytic membrane reactors containing them

A process for separation of oxygen from an oxygen-containing gas which comprises the steps of:

• (A) providing a catalytic membrane reactor cell having an oxidation zone and a reduction zone separated by a gas-impermeable membrane having a reduction surface and an oxidation surface;
• (B) heating said reactor cell to a temperature of from about 300° C. to about 1200° C.;
• (C) passing an oxygen-containing gas in contact with the reduction surface of said membrane of said heated reactor in said reduction zone;
• and
• (D) providing for collection of separated oxygen from said oxidation zone;
• wherein the membrane comprises a mixed metal oxide material having the general stoichiometry:
• A2−xA′xB2−yB′yO5+z
• where:
• A is an alkaline earth metal ion or mixture of alkaline earth metal ions;
• A′ is a metal ion or mixture of metal ions where the metal is selected from the group consisting of the lanthanide series or is yttrium;
• B is a metal ion or mixture of metal ions wherein the metal is selected from the group consisting of 3d transition metals, and the group 13 metals;
• B′ is a metal ion or mixture of metal ions where the metal is selected from the group consisting of the 3d transition metals, the group 13 metals, the lanthanides and yttrium;
• x is a number greater than or equal to 0 and less than or equal to 2;
• y is a number greater than or equal to 0 and less than or equal to 2;
• and
• z is a number greater than zero and less than one that renders the compound charge neutral.

A process for production of synthesis gas which comprises the steps of:

• (A) providing a catalytic membrane reactor cell having an oxidation zone and a reduction zone separated by a gas-impermeable membrane having a reduction surface and an oxidation surface;
• (B) heating said reactor cell to a temperature of from about 300° C. to about 1200° C.;
• (C) passing an oxygen-containing gas in contact with the reduction surface of said membrane of said heated reactor in said reduction zone;
• and
• (D) providing methane or a mixture of CO2 and methane in contact with the oxidation surface of said membrane of said heated reactor in said oxidation zone;
• wherein the membrane comprises a mixed metal oxide material having the general stoichiometry:
• A2−xA′xB2−yB′yO5+z
• where:
• A is an alkaline earth metal ion or mixture of alkaline earth metal ions;
• A′ is a metal ion or mixture of metal ions where the metal is selected from the group consisting of the lanthanide series or is yttrium;
• B is a metal ion or mixture of metal ions wherein the metal is selected from the group consisting of 3d transition metals, and the group 13 metals;
• B′ is a metal ion or mixture of metal ions where the metal is selected from the group consisting of the 3d transition metals, the group 13 metals, the lanthanides and yttrium;
• x is a number greater than or equal to 0 and less than or equal to 2;
• y is a number greater than or equal to 0 and less than or equal to 2;
• and
• z is a number greater than zero and less than one that renders the compound charge neutral.

A process for making a gas-impermeable membrane for use in a catalytic membrane reactor which comprises the steps of:

• (A) combining metal precursors of the metals A, A′, B and B′ in the stoichiometry:
• A2−xA′xB2−yB′yO5+z
• where:
• A is an alkaline earth metal ion or mixture of alkaline earth metal ions;
• A′ is a metal ion or mixture of metal ions where the metal is selected from the group consisting of the lanthanide series or is yttrium;
• B is a metal ion or mixture of metal ions wherein the metal is selected from the group consisting of 3d transition metals, and the group 13 metals;
• B′ is a metal ion or mixture of metal ions where the metal is selected from the group consisting of the 3d transition metals, the group 13 metals, the lanthanides and yttrium;
• x is a number greater than or equal to 0 and less than or equal to 2;
• y is a number greater than or equal 0 and less than or equal to 2;
• and
• z is a number greater than zero and less than one that renders the compound charge neutral
• to form a homogeneous mixture;
• (B) calcining the homogeneous mixture at temperatures up to about 1450° C. for 12 h in atmosphere;
• (C) reducing the particle size of the sintered mixture by attrition;
• (D) pressing the reduced-particle size mixture into a selected membrane shape;
• and
• (E) sintering the pressed shaped membrane at a temperature from about 1300° C. to about 1450° C. for 4 hours in atmosphere to obtain a sintered membrane of greater than or equal to 90% theoretical density.