In the present work, a new laboratory device specifically developed to obtain microchannels to test the process intensification effects on a suitable test reaction will be described. Ideally, this device represents a connection between a traditional tubular packed-bed reactor and the recently appeared microreactors that are very efficient, as it is well-known, in mass- and energy-transfer operations. To test the performance of this microreactor, the decomposition of hydrogen peroxide (H2O2) has been chosen as a test reaction. This reaction is of great industrial interest, because many processes use H2O2 as an oxidizing agent and the decomposition of the excess is normally performed under batch conditions by creating an alkaline medium. We observed that the H2O2 decomposition can also be promoted by stainless steel acting as a catalyst. Therefore, the decomposition of H2O2 is particularly enhanced in our device that is characterized by a relatively high surface area of stainless steel per unit of packing v...