Microchannel apparatus, methods of making microchannel apparatus, and processes of conducting unit operations

A process of conducting a unit operation in device comprising a step of passing a process stream into a device comprising:

• a substrate having a surface, the surface having a first section and a second section;
• a first support on the first section of the surface of the substrate and a first thin sheet over the support and a microchannel between the substrate and the thin sheet, wherein the microchannel has a thickness defined by the surface of the support and a first surface of the thin sheet;
• wherein the first support has a thickness that is substantially equal to the thickness of the microchannel;
• a second support on the second section of the surface of the substrate and a second thin sheet over the second support and a first channel between a second surface of the first thin sheet and a surface of the second thin sheet, and a second channel between the substrate and the surface of the second thin sheet, and wherein the second support has a thickness that is greater than the thickness of the first support;
• and
• channel walls on the surface of the substrate and adjacent to the microchannel such that there is a continuous flow path between the microchannel and the second channel;
• and wherein the thickness of the second channel is greater than the thickness of the microchannel;
• and
• wherein the process stream passes through the continuous flow path formed by the microchannel and the second channel.