Glass-ceramic seals for ceramic membrane chemical reactor application
AssigneeEltron Research, Inc.
InventorsJames B. Schutz, Thomas F. Barton
Life of this patent
Estimating the term…
Abstract
Glass-ceramic sealants for ceramic membrane reactors, ceramic membrane sealed to holders or substrates and methods of making seals between two ceramic materials or between a ceramic and a metal or metal alloy are provided. These sealants combine silicate glass-ceramic materials with selected metal oxides and, optionally, materials similar or identical to the materials being sealed, and employ thermal processing so that the resultant materials will have a thermal expansion coefficient that substantially matches the thermal expansion coefficients of the two materials. Surfaces of the ceramic sealant that are exposed to reactive atmospheres can be protected by providing a metal or metallic alloy layer over the ceramic seal.
Claims48
A sealant composition comprising a mixture by weight of about 40% to about 85% SiO2 and three or more metal oxides selected from the group aluminum oxide, cobalt oxide, sodium oxide, boron oxide, calcium oxide, magnesium oxide, zinc oxide, titanium oxide, lithium oxide, potassium oxide, phosphorous oxide and zirconium oxide combined with 0.5% to about 80% by weight of a ceramic membrane material wherein the ceramic membrane material is an ionic or electronic conductor material of the formula:
- AxA′x′ByB′y′O5+z
- where:
- A is a lanthanide metal which includes:
- the lanthanides and yttriun, e.g., La, Ce,
- Pr, Nd, Pm, Sm, Eu, Gd, Th, Dy, Ho, Rr, Tm, Yb, Lu and Yt, or mixtures thereof;
- A′ is a Group 2b element of the Periodic Table;
- B is an element selected from the group consisting of Al, Ga, In, or mixtures thereof;
- and
- B′ is a d block transition metal, Mg, or mixture of such elements;
- y,y′, x and x′0;
- x+x′=2
- y+y′=2 and z is a number that makes the material charge neutral.
A sealant composition made by combining 40% to about 85% of SiO2 with three or more metal oxides selected from the group of metal oxides of aluminum, cobalt, sodium, calcium, magnesium, zinc, titanium, lithium, potassium, phosphorous, and zirconiumn with about 0.5% to about 80% by weight of a ceramic membrane material that is an ionic or electronic conductor material of the formula:
- AxA′x′ByB′y′O5+z
- where:
- A is a lanthanide metal which includes:
- the lanthanides and yttrium, e.g., La, Ce,
- Pr, Nd, ?m, Sm, Bu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Yt, or mixtures thereof;
- A′ is a Group 2b element of the Periodic Table;
- B is an element selected from the group consisting of Al, Ga, In, or mixtures thereof, and
- B′ is a d block transition metal, Mg, or mixture of such elements;
- y,y′, x and x′0;
- x+x′=2
- y+y′=2 and z is a number that makes the material charge neutral,
- and subjecting the mixture to temperatures between about 960° C. to 1200° C. for up to about 24 hours.
A method for forming a seal between a ceramic membrane and a ceramic, metal or metal alloy substrate which comprises the steps of:
- providing a sealant composition comprising a mixture by weight of about 40% to about 80% SiO2 and three or more metal oxides selected from the group consisting of aluminum oxide, cobalt oxide, sodium oxide, boron oxide, calcium oxide, magnesium oxide, zinc oxide, titanium oxide, lithium oxide, potassium oxide, phosphorus oxide and zirconium oxide;
- contacting the sealant with a ceramic membrane and the substrate;
- heating the sealant to a sufficiently high temperature to form a substantially gas-impermeable seal between the membrane and the substrate;
- and
- providing a metal or metallic alloy layer on surfaces of the seal.
A gas-impermeable seal formed between a ceramic membrane and a substrate or holder wherein the seal is formed using a sealant composition comprising a mixture by weight of about 40% to about 85% SiO2 and three or more metal oxides selected from the group aluminum oxide, cobalt oxide, sodium oxide, boron oxide, calcium oxide, magnesium oxide, zinc oxide, titanium oxide, lithium oxide, potassium oxide, phosphorous oxide and zirconium oxide wherein the surfaces of the gas impermeable seal that are not in contact with the ceramic membrane, the substrate or the holder are coated with a metal or metallic alloy.
A seal assembly for a ceramic membrane in a catalytic ceramic membrane reactor which comprises:
- a tubular ceramic membrane,
- a membrane holder having a cavity with walls that taper for receiving the ceramic membrane tube;
- and
- a glass impermeable seal formed between the outside wall of the ceramic membrane tube and the membrane holder
- wherein the seal is formed from a sealant comprising a mixture by weight of about 40% to about 80% SiO2 and three or more metal oxides selected from the group consisting of aluminum oxide, cobalt oxide, sodium oxide, boron oxide, calcium oxide, magnesium oxide, zinc oxide, titanium oxide, lithiumn oxide, potassium oxide, phosphorus oxide and zirconium oxide.
Dependencies are inferred from the claim text.