Catalytic microstructured reactors

For the treatment of 1.5 m h in the microreactor with a space time of 0.052 s we need a reactor volume of = 2.17-10 m. Therefore, we need 471 parallel channels. An MSR consisting of 20 plates and 25 channels per plate results in 500 channels sufficient for the task of toxic elimination as described at the beginning. 

The pressure drop in the channel reactor can be estimated with Equation 6.9  

Compared to the packed bed reactor the pressure drop is roughly seven times lower. 

In the previous sections, the mass transfer and the pressure drop properties of three different microstructured devices for fast catalytic reactions have been assessed. In the present chapter, we compare their mass transfer performance while considering the energy demand in order to choose an appropriate design of microreactor for an eventual catalytic reaction. 

The mass transfer in forced flow is trade-off between the attainable mass transfer time, t, and the energy input. The nonidentical geometries of the different devices complicate the direct comparison. Therefore, dimensionless numbers are used. The mass transfer performance is characterized by the ratio between the space time of the fluid and the characteristic mass transfer time. This ratio corresponds to the first Damkohler number for mass transfer. Whereas the porosity of a packed bed reactor is mostly in the order of 0.35 0.45 depending on 

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Mass Transfer in Catalytic Microstructured Reactors 247 Table 6.3 Mass transfer characteristics for different channel geometries [53],... 

Rebrov EV. Sol-gel synthesis of zeolitic coatings and their application in catalytic microstructured reactors. Catal. Ind. 2009 1(1) 322-347. 

The past decade has seen significant advances in the ability to synthesize different types of microporous coatings with ordered structures from a wide range of different precursors. Sol-gel hydrothermal synthesis is one of the most promising methods for obtaining zeolitic coatings (films and membranes) on the internal surface of channels of catalytic microstructured reactors. Zeolite[Pg.277]

Kiwi-Minsker L, Renken A (2005) Microstructured reactors for catalytic reactions. Catal Today 110 2-14... 

Yube, K. and Furuta, M. and Aoki, N. and Mae, K. (2007). Control of selectivity in phenol hydroxylation using microstructured catalytic wall reactors. Applied Catalysis A General 327, 278-286... 

Mayer J, Fichtner M, Wolf D, Schubert K. A microstructured reactor for the catalytic partial oxidation of methane to syngas. Proceedings of the 3rd International Conference on Microreaction Technology. Berlin Springer, 2000 187-196. 

A major problem in using microstructured reactors for heterogeneously catalyzed gas-phase reactions is how to introduce the catalytic active phase. The possibilities are to (i) introduce the solid catalyst in the form of a micro-sized packed bed, (ii) use a catalytic wall reactor or (iii) to use novel designs. Kiwi-Minsker and Renken [160] have discussed in detail these alternatives. 

I. Aartun, T. Gjervan, H. Venvik, O. Gorke, P. Pfeifer, M. Fathi, A. Holmen, K. Schubert, Catalytic conversion of propane to hydrogen in microstructured reactors, Chem. Eng. J. 101 (2004) 93. 

O. Schwarz, B. Frank, C. Hess, R. Schomacker, Characterisation and catalytic testing of VOx/A1203 catalysts for microstructured reactors, Catal. Commun. 9 (2008) 229. 

Park et al. [43] reported a microstructured reactor with catalytic nickel plates, which is newly designed and developed for proper heat management in an exothermic WGSR. 

The use of microstructured catalytic wall reactors offers an interesting option for the revamping of existing plants. The key idea of this so-called booster concept... 

Integration of various components is an important issue for the DCF systems. The simple scale-up of microreactors is not enough as the DCF system. A DCF system should consist of not only reactors but also other factory parts like a mixer, separator, and temperature controller. Many integrated microreaction systems have been reported and some of these are commercially available. For example, K. F. Jensen s group has reported an integrated microreactor system for gas-phase catalytic reactions using microstructured reactors and other devices on a computer board [13]. They have achieved computer control over the reaction system through this device as shown in Fig. 6. 

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