Chemical reaction engineering reactor design

Flow reactor systems provide the heart of chemical reactors that enable the continuous conversion of various reactants, very often in the presence of catalysts, into desired new products. Contemporary chemical reaction engineering has designed a wide variety of flow reactor systems that have been customized for the specific chemical-conversion processes they facilitate. Flow reactors have become essential in process industries as they provide a very effective way of converting r w materials into desired products. The world s demand for gasoline, for example, could hardly be met without the flow reactor enabling fluid catalytic crocking of low-value hydrocarbons into high-value hydrocarbons derived from crude oil. 

Chemical reaction engineering is part of chemical engineering in general. It aims at controlling the chemical conversion on a technical scale and will ultimately lead to appropriate and successful reactor design. An important part is played by various factors, such as flow phenomena, mass and heat transfer, and reaction kinetics. It will be clear that in the first place it is necessary to know these factors separately. 

Shinnar, R., Use of Residence and Contact Time Distributions in Reactor Design, Chapter 2, pp. 63-149 of Chemical Reaction and Reactor Engineering, Carberry, J. J. and Varma, A., Eds., Marcel Dekker, New York, 1987. 

Froment, G. F. and Bischoff, K. B. Chemical Reactor Analysis and Design, 2nd edn (Wiley, 1990). Levenspiel, O. Chemical Reaction Engineering, 3rd edn (Wiley, 1998). 

Froment, G. F., Analysis and Design of Fixed Bed Catalytic Reactors, in Chemical Reaction Engineering, Adv. Chem. Series, 109 (1), American Chemical Society, Washington, D.C., 1972. 

In this introductory chapter, we first consider what chemical kinetics and chemical reaction engineering (CRE) are about, and how they are interrelated. We then introduce some important aspects of kinetics and CRE, including the involvement of chemical stoichiometry, thermodynamics and equilibrium, and various other rate processes. Since the rate of reaction is of primary importance, we must pay attention to how it is defined, measured, and represented, and to the parameters that affect it. We also introduce some of the main considerations in reactor design, and parameters affecting reactor performance. These considerations lead to a plan of treatment for the following chapters. 

Chemical reaction engineering (CRE) is concerned with the rational design and/or analysis of performance of chemical reactors. What is a chemical reactor, and what does its rational design involve A chemical reactor is a device in which change in com-... 

Our treatment of Chemical Reaction Engineering begins in Chapters 1 and 2 and continues in Chapters 11-24. After an introduction (Chapter 11) surveying the field, the next five Chapters (12-16) are devoted to performance and design characteristics of four ideal reactor models (batch, CSTR, plug-flow, and laminar-flow), and to the characteristics of various types of ideal flow involved in continuous-flow reactors. Chapter 17 deals with comparisons and combinations of ideal reactors. Chapter 18 deals with ideal reactors for complex (multireaction) systems. Chapters 19 and 20 treat nonideal flow and reactor considerations taking this into account. Chapters 21-24 provide an introduction to reactors for multiphase systems, including fixed-bed catalytic reactors, fluidized-bed reactors, and reactors for gas-solid and gas-liquid reactions. 

Hill, CG, An Introduction to Chemical Engineering Kinetics and Reactor Design, Wiley, New York, NY, 1977. Holland, CD, RG Anthony, Fundamentals of Chemical Reaction Engineering, Prentice-Hall, Englewood Cliffs, NJ, 1989. 

Reactor design uses information, knowledge, and experience from a variety of areas—thermodynamics, chemical kinetics, fluid mechanics, heat transfer, mass transfer, and economics. Chemical reaction engineering is the synthesis of all these factors with the aim of properly designing a chemical reactor. 

Chemical reaction engineering is that engineering activity concerned with the exploitation of chemical reactions on a commercial scale. Its goal is the successful design and operation of chemical reactors, and probably more than any other activity it sets chemical engineering apart as a distinct branch of the engineering profession. 

We regard the essential aspects of chemical reaction engineering to include multiple reactions, energy management, and catalytic processes so we regard the first seven chapters as the core material in a course. Then the final five chapters consider topics such as environmental, polymer, sohds, biological, and combustion reactions and reactors, subjects that may be considered optional in an introductory course. We recommend that an instmctor attempt to complete the first seven chapters within perhaps 3/4 of a term to allow time to select from these topics and chapters. The final chapter on multiphase reactors is of course very important, but our intent is only to introduce some of the ideas that are important in its design. 

To understand how degradation data are treated, it is convenient to mention the basics of chemical reaction kinetics. The principles of chemical reaction engineering can be found in any reaction engineering or reactor design textbook [26]. A chemical reaction is the process whereby one or more components are transformed into one or more different components. The rate of reaction is the velocity at which the component(s) are being transformed in a chemical reaction. For the chemical reaction... 

It is generally desirable to integrate measurements representing a working catalyst surface with measurements that characterize the activity, selectivity, and/or stability of the catalyst, such as can be determined by use of gas chromatography or mass spectrometry of products. It is important to keep in mind that when a reactor is designed to serve optimally as a cell for measurements of catalyst surface properties, it may not be the kind of ideal reactor that would provide activity, selectivity, or stability data that can be interpreted fundamentally in terms of kinetics and chemical reaction engineering. 

If a certain process can produce a product, it is important to know how fast the process can take place. Kinetics deals with rate of a reaction and how it is affected by various chemical and physical conditions. This is where the expertise of chemical engineers familiar with chemical kinetics and reactor design plays a major role. Similar techniques can be employed to deal with enzyme or cell kinetics. To design an effective bioreactor... 

Keywords Reactor design Potential environmental impact Chemical reaction engineering Impact analysis... 

This section has presented a brief review of some of the important kinetic concepts encountered in reactor analysis, modeling, and control. These concepts must be understood within the context of how they affect reactor temperature control and other aspects of reactor control. We recognize that many excellent reference books on chemical reaction engineering are available. These books cover the topic of kinetics and a host of other reactor design concepts in extensive depth. Our intention is not to attempt to provide anything like the scope of that material, so we assume some familiarity with it. A short list of excellent reference books includes... 

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