Reactor design fundamentals hydrodynamics

It is possible to assume that kinetic and hydrodynamic methods of reactors analysis and design are well advanced at present. Methods of computer simulation and modelling are widely used. So, we can say that if we know processes kinetic and hydrodynamic parameters and fundamental particularities of reactor functioning we can calculate all process characteristics and its stmcture, we also can predict effectiveness of apparatus operation and consumer properties of chemical production. Meanwhile criterion function development for calculation and organization of novel processes and optimization of present productions require overcoming of a big number of problems in production practice. This principle is satisfactory enough for processes with low or medium reactions rates, when creation of isothermal conditions in apparatus is easy. In this case it is easy to calculate and reproduce in working conditions all characteristics of chemical process and to control the last ones. 

Hydrodynamics, mass, and heat transfer in the commonly used three-phase fixed-bed reactors were briefly outlined. Also, scale-up rules and alternative ways to scale down trickle-bed reactors are discussed. In spite of the extensive studies on the hydrodynamics, mass, and heat transfer in three-phase fixed-bed reactors, clearly, a lot of work remains to be done in providing a fundamentally based description of the effect of pressure on the parameters of importance in three-phase fixed-bed reactors operation, design, and scale-up or scale-down. It is evident that atmospheric data and models/correlations cannot, in general, be extrapolated to operation at elevated pressures. The physics conveyed by the standard two-phase flow models is minimalistic because it insufficiently describes the role and presence of interfaces and their thermodynamic properties. The explicit inclusion of interfaces and interfacial properties is essential because they are known to have a significant role in determining the thermodynamic state of the whole system. 

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