Microreactors fast/exothermic reactions

Schneider, M.-A., Ryser, T., Maeder, P. and Stoessel, F. (2004) A microreactor-based system for the study of fast exothermic reactions in liquid phase characterization of the system. Chemical Engineering Journal, 101 (1-3), 241-50. 

Schneider, M.A. and Stoessel, F. (2005) Determination of the kinetic parameters of fast exothermal reactions using a novel microreactor-based calorimeter. Chemical Engineering Journal, 115, 73-83. 

A multistep gas-liquid process using a falling-film microreactor was carried out for the ozonolysis of a steroid that is a fast and highly exothermic reaction [50],... 

Haber, J., Kashid, M.N., Borhani, N., Thome, J., Krtschil, U., Renken, A., and Kiwi-Minsker, L. (2013) Infrared imaging of temperature profiles in microreactors for fast and exothermic reactions. Chem. Eng. J, 214, 97-105. 

Until recently, the temperature control of highly exothermic reactions using the microreaction systems was mainly based on the removal of heat in order to prevent hot spot formation and thermal runaway [29]. More recently, however, research has focused on techniques that enable microreactors to be heated because they can efficiently dissipate the heat. If a microheat exchanger is integrated into a microreactor, both effects can be combined, that is, either enabling fast heat supply in the reactor or heat removal from the reactor [30]. In practice, strongly exothermic reactions such as nitration, oxidation, chlorination, and even fluorination with elementary fluorine (in microreactors made of nickel) can be carried out in microreactor systems under nearly isothermal conditions [31]. 

Endothermic and exothermic reactions can be successfully combined in microreactors because of the fast heat removal that reduces the required heat for the endothermic reaction. Tadbir and Akbari [63] numerically simulated methanol steam reforming in combination with methanol oxidation reaction in the neighboring chaimels of the microreactor. The authors used the mechanism of Peppley et al. [64] for the methanol steam reforming reactions, while the reaction rate for the methanol oxidation reaction was adopted from Ref [65], Thus, the following reactions were considered to be main reactions ... 

Three examples of new designs of single-injection MSR and one example of multi-injection reactor applied for fast and exothermic liquid phase reactions are presented. Finally, it is demonstrated that the process intensification has been achieved using these microreactors. 

A suitable microreactor system corresponding to the above mentioned requirements was developed by Worz et al. [89]. Their installation consisted of 32 stainless steel channels of 900 X 60 pm size separated by cooling channels (Figure 7.24). Reactant and the acid were mixed extremely fast in these microchannels and cooled simultaneously. As the product is sensitive for consecutive reactions, it is obvious that the absence of backmixing increases the product yield. At a temperature of 20 C, a maximum yield of 90-95% could be achieved with a residence time of 30 s. The reaction is quenched by diluting the concentrated sulfuric acid-reactant mixture with water. The dilution of concentrated sulfuric acid has an even higher exothermicity and must carried... 

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