Protected alloy surfaces in microchannel apparatus and catalysts, alumina supported catalysts, catalyst intermediates, and methods of forming catalysts and microchannel apparatus

A microchannel reactor or separator, comprising:

• a microchannel defined by four microchannel walls that form a rectangular channel;
• and
• a post-assembly coating of aluminide disposed over the at least one microchannel wall;
• wherein the microchannel has a rectangular cross-section and wherein the thickness of the coating at a corner of the rectangle is within 25% of the coating thickness measured at the midpoint between two corners of the rectangle;
• and
• further comprising:
• a layer of alumina disposed over the layer of aluminide;
• and
• a catalytic material disposed over the layer of alumina.

A microchannel reactor or separator, comprising:

• a complex microchannel defined by at least one microchannel wall;
• and
• a layer of aluminide disposed over the at least one microchannel wall;
• wherein the complex microchannel is an interior microchannel that comprises one or more of the following characteristics:
• at least one contiguous microchannel having at least one angle of at least 45° with respect to itself, a length of 20 cm or more along with a height or width of 2 mm or less, at least one microchannel that splits into at least 2 sub-microchannels in parallel, one of at least 2 adjacent microchannels having an adjacent length of at least one cm that are connected by plural orifices along a common microchannel wall where the areas of the orifices amounts to 20% or less of the area of the microchannel wall in which the orifices are located and where each orifice is 1.0 mm2 or smaller, and one of at least 5 parallel microchannels having a length of at least 1 cm and having openings to an internal manifold wherein the internal manifold comprises at least one dimension that is no more than three times the minimum height or width of the parallel microchannels;
• wherein the complex microchannel comprises a microchannel that is adjacent to a second microchannel for a length of at least 1 cm, and
• wherein the complex microchannel and the second microchannel are connected by plural orifices along a common microchannel wall wherein the area of the plural orifices amount to 20% or less of the area of the microchannel wall in which the orifices are located, and wherein the area of each orifice is 0.6 mm2 or less.

A microchannel reactor or separator, comprising:

• a complex microchannel defined by at least one microchannel wall;
• and
• a layer of aluminide disposed over the at least one microchannel wall;
• wherein the complex microchannel is an interior microchannel that comprises one or more of the following characteristics:
• at least one contiguous microchannel having at least one angle of at least 45° with respect to itself, a length of 20 cm or more along with a height or width of 2 mm or less, at least one microchannel that splits into at least 2 sub-microchannels in parallel, one of at least 2 adjacent microchannels having an adjacent length of at least one cm that are connected by plural orifices along a common microchannel wall where the areas of the orifices amounts to 20% or less of the area of the microchannel wall in which the orifices are located and where each orifice is 1.0 mm2 or smaller, and one of at least 5 parallel microchannels having a length of at least 1 cm and having openings to an internal manifold wherein the internal manifold comprises at least one dimension that is no more than three times the minimum height or width of the parallel microchannels;
• wherein the complex microchannel comprises a rectangular cross-section and wherein the thickness of the aluminide layer at a corner of the rectangle is within 25% of the coating thickness measured at the midpoint between two corners of the rectangle;
• wherein the apparatus comprises at least 3 groups of parallel microchannels, wherein the microchannels in each of said at least 3 groups are connected to a common manifold, and wherein each of said common manifolds comprises a feature or features that tends to equalize flow through the microchannels.

A microchannel reactor or separator, comprising:

• a complex microchannel defined by at least one microchannel wall;
• and
• a layer of aluminide disposed over the at least one microchannel wall;
• wherein the complex microchannel is an interior microchannel that comprises one or more of the following characteristics:
• at least one contiguous microchannel having at least one angle of at least 45° with respect to itself, a length of 20 cm or more along with a height or width of 2 mm or less, at least one microchannel that splits into at least 2 sub-microchannels in parallel, one of at least 2 adjacent microchannels having an adjacent length of at least one cm that are connected by plural orifices along a common microchannel wall where the areas of the orifices amounts to 20% or less of the area of the microchannel wall in which the orifices are located and where each orifice is 1.0 mm2 or smaller, and one of at least 5 parallel microchannels having a length of at least 1 cm and having openings to an internal manifold wherein the internal manifold comprises at least one dimension that is no more than three times the minimum height or width of the parallel microchannels;
• and further comprising a layer of alumina disposed over the layer of aluminide;
• and
• a catalytic material disposed in the microchannel;
• wherein the complex microchannel is a microchannel in a array of planar microchannels, and further wherein the reactor or separator comprises at least 3 arrays of planar microchannels;
• and further wherein the reactor or separator comprises at least 10 heat exchangers interleaved with at least 10 reaction or separator microchannels.