(61a) Structured Microreactors for Intensification of Catalytic Process

Kiwi-Minsker, L. - Presenter, Ecole Polytechnique Fédérale de Lausanne
Renken, A. - Presenter, École Polytechnique Fédérale de Lausanne

The manufacture of chemicals in catalytic microreactors has become recently a new branch of chemical reaction engineering focusing on process intensification and safety. Chemical microstructured reactors (MSR) are devices containing open paths for fluids with dimensions in the sub-millimeter range. Mostly MSR have multiple parallel channels with diameters between ten and several hundred micrometers where the chemical transformation occur. This gives a high specific surface area in the range of 10000 to 50000 m2/m3 and allows an effective mass and heat transfer if compared to more traditional chemical reactors having usually ~100 m2/m3. Another important feature of MSR is that the heat exchange and the reaction are often performed in the same devise. MSR are operated under laminar flow with the heat transfer coefficient for liquids about 10 kW/(m2×K). This is one order of magnitude higher than in the traditional heat exchangers allowing to avoid hot-spots formation, to attain higher reaction temperatures and to reduce reaction volumes. This in turn improves the energy efficiency and reduces the operational cost. An integrated heat exchange makes the key difference between MSR and other structured reactors like honeycombs. Isothermal conditions combined with short residence times and narrow residence time distributions are the main characteristics of MSR. Small reactor dimensions facilitate the use of distributed production units at the place of consumption. Moreover, the small inventories of reactants and products lead to an inherent safety during the reactor operation even under conditions within the explosion regime. This avoids the high cost of transport and storage of dangerous materials.

In the present paper novel designs of MSR and the incorporation of catalytically active phase will be presented. The beneficial effect of improved heat transfer due to reactor miniaturization will be demonstrated through some case studies.