The Micro Unit Operations Concept

There are a few micro structured reactor plants of table-top size on the market [21, 22, 34—42] and even one of larger scale for production purposes [43-45], Nevertheless, engineers do not have much experience in designing micro structured reactor plants and, of course, systematic tools for designing and control are also lacking[13]. 

In scouting work, Hasebe [13] described a concept for the application and design rules for a micro structured reactor plant. First the reasons for performing a chemical reaction in a micro device must be clear. Either the target product cannot be produced conventionally, or the production efficiency of the target product can be drastically improved. Currently many chemical reactions are performed in micro reactors (see, e.g., [9]), but it is not clear how many of them fit with the above-mentioned rules. 

The economic benefit is one of the dominant problems if a micro structured reactor plant is used for chemical production. Without any doubt, an overall flow rate through a micro structured device can be achieved that is comparable to that with a conventional batch process. However, the residence time is very short because of the dimensions of a microstructured device. If the reaction kinetics are slow, an additional device is necessary to increase a dwell time. Hence, much effort should be devoted to increasing the reaction rate instead of transferring the standard protocol to a micro structured reactor [13]. 

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