Microstructure devices for water evaporation

Evaporation of liquids is of major interest for many fields in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of superheated steam is mandatory for numerous processes. Generally, this is performed by the use of classical pool boiling and evaporation process equipment, providing relatively limited performance, or by other systems like falling-film or membrane evaporators. Due to the advantages of microstructure devices especially in chemical process engineering the interest in microstructure evaporators and steam generators has increased through the last decade. In this publication different microstructure devices used for evaporation and generation of steam are described. Starting with simple liquid-heated devices, different types of electrically powered devices containing micro channels as well as non-channel microstructures will be shown. While evaporation of liquids in crossflow and counterflow or co-current flow micro-channel devices is possible, it is, in many cases, not possible to obtain superheated steam due to certain boundary conditions. Thus, a new design was proposed to obtain complete evaporation and superheating of the generated steam.