Reaction Engineering Fundamentals

The assessment whether or not a chemical reaction can be performed in a safe and controlled way under normal as well as upset operating conditions is based on models originating from chemical reaction engineering. This explains why some fundamentals of these models have to be introduced first. 

This cannot and shall not be a substitute for a text book on chemical engineering. On the contrary, it is advisable to turn to specialist literature on chemical and especially on reaction engineering for the derivation of certain fects. Highly recommended examples are the standard text books by Westerterp and by Baems, Hofinann, Renken 

A chemical transition process is always characterized by its stoichiometry and its extent of reaction independent of the mode of process operation. The rate of change in extent, however, depends on the mode of process operation, on the reaction rate and, in the case of heterogeneous reactions, on the mass transfer. In order to account for the mode of operation appropriately, models are required for the different reactor types. This is all comprehensively described in the overall mass balance of the system. 

The tiiermal behaviour of a chemical reactor depends on the thermodynamics of the process, on the reaction rate, vtdiich has already been mentioned above, but also on the mode of exchange with the environment. This is completely described in the overall heat balance of the system. The following sections will present the main balance equations, which are required for the subsequent safety assessment, as well as definitions and interpretation of characteristic numbers used in their presentatioiL 

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In addition to these complications, Moad (1999) notes that, for typical reactive modifications, the amount of modification can be quite small (0.5-2 mol%) and therefore very difficult to characterize. However, Moad (1999) does suggest some techniques such as chemical methods, FT-IR, NMR and DSC that may be useful to aid characterization. Janssen (1998) also notes complications of thermal, hydrodynamic and chemical instabilities that can occur in reactive extrusion that must be addressed by combining knowledge of the chemistry and of the physics (flow behaviour, mixing) of the reactive extrusion process. Xanthos (1992) presents the importance of understanding both the chemistry and the reaction engineering fundamentals of reactive extrusion, in order better to understand and model the process in practice. 

This book focuses on reaction engineering aspects, such as design and characterization, for homogeneous and multiphase reactions. On the basis of chemical reaction engineering fundamentals, it addresses the conditions under which these devices are beneficial, how they should be designed, and how such devices can be integrated or applied in a chemical process. 

A few excellent books are also available on reaction engineering in the widest sense and from a fundamental point of view. These books treat the subject with mathematical rigor, yet are too inclusive to have any space left for details on experimental procedures. Here, the reader can find more insight and practical examples on the development and scale-up of... 

Brotz, W. 1965, Fundamentals of Chemical Reaction Engineering. Addison-Wesley, Reading, MA... 

Sada, E., Kumazawa, H. and Aoyama, M., 1988. Reaction kinetics and controls of size and shape of geothite fine particles in the production of ferrous hydroxide. Chemical Engineering Fundamentals, 71, 73-82. 

Yagi, H., Nagashima, S. and Hikita, H., 1988. Semibatch precipitation accompanying gas-liquid reaction. Chemical Engineering Fundamentals, 65, 109-119. 

Hessel, V., Hardt, S., and Lowe, H. (2004) Chemical Micro Process Engineering Fundamentals, Modeling, and Reactions, Wiley-VCH Verlag GmbH. 

V. Hessel, S. Hardt and H. Lowe Chemical Micro Process Engineering - Fundamentals, Modelling and Reactions, Wiley-VCH, Weinheim (2004). 

Chemical Micro Process Engineering Fundamentals, Modelling and Reactions Volker Hessel, Steffen Hardt, Holger Lowe... 

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