Microchannel apparatus comprising plural microchannels and methods of conducting unit operations

A microcomponent apparatus for conducting unit operations comprising:

• a first microcomponent device having a first inlet, first exit, first header, a first array of microchannels and a second array of microchannels;
• wherein the first microcomponent device is a laminated device wherein the first array of microchannels are in a first shim and the second array of microchannels are in a second shim and wherein the first header comprises an opening in said first shim and an opening said second shim;
• wherein the first inlet is connected to the first array of microchannels;
• wherein the first array of microchannels are connected to a first exit that is connected to the first header;
• wherein, during operation, a first stream enters the first inlet of the first microcomponent device and is distributed among said first array of microchannels and a first unit operation is performed on said first stream, said first stream passes through the first exit into the first header;
• said first header being capable of modifying said first stream by a second unit operation;
• said first header connected to a second array of microchannels within the first device;
• wherein, during operation, said first stream enters said first microcomponent device and is distributed among the second array of microchannels wherein said first unit operation is again performed on first stream.