While the dimensions of the individual channels are small, a micro process engineering device ("microstructured reactor") can contain many thousands of such channels, and the overall size of a microstructured reactor can be on the scale of meters. The objective of micro process engineering is not primarily to miniaturize production plants, but to increase yields and selectivities of chemical reactions, thus reducing the cost of chemical production. This goal can be achieved by either using chemical reactions that cannot be conducted in larger volumina, or by running chemical reactions at parameters (temperatures, pressures, concentrations) that are inaccessible in larger volumina due
to safety constraints. For example, the detonation of the stoichiometric mixture of two volume unit of hydrogen gas and
one volume unit of oxygen gas does not propagate in microchannels
with a sufficiently small diameter. This property is referred to as the
"intrinsic safety" of microstructured reactors. The improvement of yields and selectivities by using novel reactions or running reactions at more extreme parameters is known as "process intensification".