Novel Concepts in Catalysis and Chemical Reactors E-Book

• Herausgeber: Wiley-VCH
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 686

Veröffentlichungsjahr: 2011

Beschreibung

The chemical process industry faces a tremendous challenge of supplying a growing and ever more demanding global population with the products we need. The average efficiency at which resources are converted into the final products is however still dramatically low. The most obvious solution is to carry out chemical conversions at much higher yields and selectivity and this is where active and selective catalysts and efficient chemical reactors play a crucial role. Written by an international team of highly experienced editors and authors from academia and industry, this ready reference focuses on how to enhance the efficiency of catalysts and reactors. It treats key topics such as molecular modeling, zeolites, MOFs, catalysis at room temperature, biocatalysis, catalysis for sustainability, structured reactors including membrane and microchannel reactors, switching from batch to continuous reactors, application of alternative energies and process intensification. By including recent achievements and trends, the book provides an up-to-date insight into the most important developments in the field of industrial catalysis and chemical reactor engineering. In addition, several ways of improving efficiency, selectivity, activity and improved methods for scale-up, modeling and design are presented in a compact manner.

Leseprobe

Contents

Preface

List of Contributors

1: Molecular Catalytic Kinetics Concepts

1.1 Key Principles of Heterogeneous Catalysis

1.2 Elementary Rate Constants and Catalytic Cycle

1.3 Linear Activation Energy-Reaction Energy Relationships

1.4 Microkinetic Expressions; Derivation of Volcano Curve

1.5 Compensation Effect

1.6 Hydrocarbon Conversion Catalyzed by Zeolites

1.7 Structure Sensitive and Insensitive Reactions

1.8 The Nonmetal Atom Sharing Rule of Low-Barrier Transition States

1.9 Summary

2: Hierarchical Porous Zeolites by Demetallation

2.1 Zeolites and Catalyst Effectiveness

2.2 Hierarchical Zeolites

2.3 Mesoporous Zeolites by Demetallation

2.4 Desilication

2.5 Conclusions and Outlook

3: Preparation of Nanosized Gold Catalysts and Oxidation at Room Temperature

3.1 Introduction

3.2 Preparation of Nanosized Gold Catalysts

3.3 Gas-Phase Oxidation Around Room Temperature

3.4 Conclusions

4: The Fascinating Structure and the Potential of Metal-Organic Frameworks

4.1 Introduction

4.2 Preparation and Structure

4.3 Applications

4.4 Conclusion

5: Enzymatic Catalysis Today and Tomorrow

5.1 Introduction

5.2 Enzymatic Catalysis Today

5.3 Enzymatic Catalysts of Tomorrow

5.4 Concluding Remarks

6: Oxidation Tools in the Synthesis of Catalysts and Related Functional Materials

6.1 Introduction

6.2 Preparation Strategies Involving Chemical Oxidative Approaches

6.3 A Catalytic Oxidation Tool. Fenton Chemistry in Solid Catalyst Synthesis

6.4 First Concept in Catalyst Design. Shifting Complexation Equilibria for Ion-Exchange by Oxidation of the Organic Chelates

6.5 Second Concept in Catalyst Design. One-Pot Synthesis of Fe Zeolite Catalysts

6.6 Third Concept in Catalyst Design. Fenton Detemplation. Mild Organic Template Removal in Micro- and Mesoporous Molecular Sieves

6.7 Concluding Remarks

7: Challenges in Catalysis for Sustainability

7.1 Introduction

7.2 Population and Human Resources

7.3 Food Security

7.4 Species and Ecosystem

7.5 Energy

7.6 Industry

7.7 The Urban Challenge

7.8 Future Advances in Catalysis for Sustainability

7.9 Conclusions

8: Catalytic Engineering in the Processing of Biomass into Chemicals

8.1 Introduction

8.2 Chemicals and Fuels from Biomass

8.3 Chemical Reaction Engineering in Biomass Transformation

8.4 Conclusions and Future Perspectives

9: Structured Reactors, a Wealth of Opportunities

9.1 Introduction

9.2 Monoliths

9.3 Other Structured Catalysts

9.4 Foams

9.5 Why are Industrial Applications of Structured Reactors so Scarce?

9.6 Concluding Remarks

10: Zeolite Membranes in Catalysis: What Is New and How Bright Is the Future?

10.1 Introduction

10.2 Zeolites: a Versatile, Well-Defined Class of Materials

10.3 Application Options

10.4 Potential Applications

10.5 Current Hurdles

10.6 Concluding Remarks and Future Outlook

11: Microstructures on Macroscale: Microchannel Reactors for Medium- and Large-Size Processes

11.1 Introduction

11.2 Background on Medium- to Large-Scale Processes in Microchannels

11.3 Fundamental Challenges of Microchannel Scale-up

11.4 Overcoming the Scale-up Challenges

11.5 Example of Scale-up through Concurrent Modeling

11.6 Conclusions

12: Intensification of Heat Transfer in Chemical Reactors: Heat Exchanger Reactors

12.1 Introduction

12.2 Examples of Heat-Exchanger Reactor Technologies

12.3 Methodology for the Characterization of the HEX Reactor

12.4 Feasibility of HEX Reactors

12.5 Conclusions

13: Reactors Using Alternative Energy Forms for Green Synthetic Routes and New Functional Products

13.1 Introduction

13.2 Energy of Electromagnetic Field

13.3 Energy of Electric Field

13.4 Energy of Magnetic Field

13.5 Energy of Acoustic Field

13.6 Energy of Flow

13.7 Energy of Centrifugal Fields-High-Gravity Systems

13.8 Conclusion

14: Switching from Batch to Continuous Processing for Fine and Intermediate-Scale Chemicals Manufacture

14.1 Introduction

14.2 Progress in Switching from Batch to Continuous

14.3 Structure of Batch Processes

14.4 Structure of Continuous Processes

14.5 Capital Cost Considerations

14.6 Revenue/Operating Cost Considerations

14.7 Key Considerations for B2C Viability

14.8 Conclusions

15: Progress in Methods for Identification of Micro- and Macroscale Physical Phenomena in Chemical Reactors: Improvements in Scale-up of Chemical Reactors

15.1 Introduction

15.2 Experimental Methods

15.3 Simulations

15.4 Microscale Measurement and Simulations

15.5 Reactor Design

15.6 The Future

Index

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“In memory of our too early deceased friend Andrzej Cybulski, the inspiring initiator of this book.”

Jacob Moulijn Andrzej Stankiewicz

Preface

The chemical process industry faces a tremendous challenge of supplying a growing and ever more demanding global population with the products it needs. The consumption of nonrenewable resources by the chemical and related industries is rapidly increasing, as on the one hand new markets open in different parts of the world for already existing products and on the other hand new types of chemical and biochemical products are brought each year to the market. However, the efficiency at which resources are converted into the final products is still dramatically low. According to the World Resources Institute, the average mass efficiency, at which the Earth’s resources are currently converted into the final products, does not exceed 25%! The remaining 75% (or more) is a major contributor to pollution, waste, and environmental disturbances. We feel that in order to achieve a ‘‘steady-state’’ and retain the Earth’s ecosphere in its present shape the resource efficiency of production processes has to increase drastically, say by a factor of three or even more. This is a figure that is both worrying and challenging to the chemists and chemical engineers.

The most obvious solution to this problem is to carry out chemical conversions at much higher yields and selectivity than is presently the case. Hence, more active and selective catalysts and more efficient ways to design better catalysts are needed. Moreover, efficient reactors with improved energy and mass transfer between reaction zone and surroundings, and eliminating the randomness and chaos (often harmful) that are characteristic of conventional reactors, are needed. Improved methods for scale-up, modeling, and design are vehicles in search for the optimal reactors. This is exactly what this book is all about. The aim of the book is to provide the reader with an up-to-date insight into the most important developments in the field of industrial catalysis and chemical reactor engineering contributing to the creation of a sustainable environment.

The search for better catalysts has been facilitated in recent years by molecular modeling. We are seeing here a step change. This is the subject of Chapter 1 (Molecular Catalytic Kinetics Concepts). New types of catalysts appeared to be more selective and active than conventional ones. Tuned mesoporous catalysts, gold catalysts, and metal organic frameworks (MOFs) that are discussed in Chapter 2 (Hierarchical Porous Zeolites by Demetallation, 3 (Preparation of Nanosized Gold Catalysts and Oxidation at Room Temperature), and 4 (The Fascinating Structure and the Potential of Metal Organic Frameworks (MOFs)), respectively, belong to this class of catalysts. Enzymes as catalysts have been known for a long time. Recent developments in this field are remarkable, particularly in the fast-growing sector of fine chemicals and pharmaceuticals, and the future is bright. New achievements and the future in this area are dealt with in Chapter 5 (Enzymatic Catalysis Today and Tomorrow). The Fenton chemistry principle is applied to produce new solid catalysts that can be efficiently used for oxidation of organics in waste waters based upon the same Fenton chemistry. Synthesis of catalysts and their applications are presented in Chapter 6 (Oxidation Tools in Synthesis of Catalysts and Related Functional Materials). Fenton chemistry probably will find many more applications in the future because it represents a much milder step than the not very sophisticated generally applied calcination step.

In the above chapters, catalysis is the tool for improvements of chemical processes, thereby reducing consumption of raw materials and energy, and emissions to environment. Progress in the direct use of catalysis in processes for protection of the environment is presented in Chapter 7 (Challenges in Catalysis for Sustainability). Progress in catalytic processes aimed at the use of renewables and wastes for production of chemicals is presented in Chapter 8 (Catalytic Engineering in Processing of Biomass into Chemicals) with particular attention paid to processing of wood into chemicals.

A random character in a reaction zone can cause flow maldistribution and nonuniform residence time of reactants in the reaction zone, resulting in decreasing conversion and selectivity. Structured catalysts (monoliths and other structures) eliminate randomness in the reaction zone. New developments are presented in Chapter 9 (Structured Reactors, a Wealth of Opportunities). Selectivity and yield can also be improved by intensification and new ways for mass and energy exchange between the reaction zone and the surroundings. This enables a better control of temperature and concentration versus time profiles, thereby approaching the optimal reaction conditions. Membranes allow for cross-flow operation; that is, a controlled supply and withdrawal of reactants from the reaction zone. Progress and industrial prospects for zeolitic membranes is presented in Chapter 10 (Zeolitic Membranes in Catalysis; What is New and How Bright is the Future?). New developments in intensification of heat transfer between the reaction zone and the surroundings are discussed in Chapters 11 (Microstructures on Macroscale: Microchannel Reactors for Medium- and Large-size Processes and 12 (Intensification of Heat Transfer in Chemical Reactors: Heat Exchanger Reactors). Specific energy sources can provide much more energy than the conventional ones or provide energy in a particular form, increasing process rates and reactor capacities significantly. Such methods are presented in Chapter 13 (Reactors Using Alternative Energy Forms for Green Synthetic Routes, and New Functional Products). Fine chemicals and pharmaceuticals are predominantly manufactured in (semi)batch-operated reactors of low efficiency. Continuous reactors provide an inviting prospect. An evaluation based upon both technical and economic considerations is presented in Chapter 14 (Switching from Batch to Continuous Processing for Fine and Intermediate-scale Chemicals Manufacture). Progress in the search for the best reactor shape and operation conditions is illustrated with achievements in studies on micro- and macroscale phemomena in the reaction zone, see Chapter 15 (Progress in Methods for Identification of Micro- and Macroscale Physical Phenomena in Chemical Reactors: Improvements in Scale-up of Chemical Reactors).

Are the developments in industrial catalysis and chemical reactor engineering presented in this book sufficient to reach the ultimate goal of fully sustainable processing? Obviously not: although numerous developments in catalysis and chemical reactors have been reported in recent years, a number of big steps are still needed. Here is the editors’ selection of topics that present significant steps, which bring us closer to that goal. We hope the topics chosen will inspire the reader to take further steps toward meeting the most important challenge to the mankind.

Andrzej Cybulski Jacob MoulijnAndrzej Stankiewicz

Note:

We sketched the above Preface with Andrzej together in early 2008, at the start of the present project. We have decided to leave it essentially unchanged. This book is above all his book. We miss him a lot.

Jacob Moulijn Andrzej Stankiewicz

List of Contributors

Luc Alaerts

Katholieke Universiteit Leuven Centre for Surface Chemistry and Catalysis Kasteelpark Arenberg 23 3001 Leuven Belgium

Bengt Andersson

Chalmers University of Technology Department of Chemistry and Biological Engineering Kemigården 4 Göteborg 41296, Sweden

Johan van den Bergh

Delft University of Technology Chemical Engineering Department Faculty of Applied Sciences Julianalaan 136 2682 BL Delft The Netherlands

Michael Cabassud

Université de Toulouse Laboratoire de Génie Chimique UMR 5503 CNRS/INPT/UPS Allee Emile Monso 31482 Toulouse France

Derek Creaser

Chalmers University of Technology Department of Chemistry and Biological Engineering Kemigården 4 Göteborg 41296, Sweden

Andrzej Cybulski†

Polish Academy of Sciences CHEMIPAN Institute of Physical Chemistry Kasprzaka 44/52 01-224 Warszawa Poland

Dirk E. De Vos

Katholieke Universiteit Leuven Centre for Surface Chemistry and Catalysis Kasteelpark Arenberg 23 3001 Leuven Belgium

Kari Eränen

Åbo Akademi Process Chemistry Centre Industrial Chemistry and Reaction Engineering 20500 Turku/Åbo Finland

Tom Van Gerven

Katholieke Universiteit Leuven Faculty of Engineering Department of Chemical Engineering Willem de Croylaan 46 3001 Leuven Belgium

Christophe Gourdon

Université de Toulouse Laboratoire de Génie Chimique UMR 5503 CNRS/INPT/UPS Allee Emile Monso 31482 Toulouse France

Johan C. Groen

Delft Solids Solutions B.V Rotterdamseweg 183c 2629 HD Delft The Netherlands

Masatake Haruta

Tokyo Metropolitan University Graduate School of Urban Environmental Sciences 1-1 Minami-osawa Hachioji Tokyo 192-0397 Japan and CREST Japan Science and Technology Agency 4-1-8 Hon-cho Kawaguchi Saitama 332-0012 Japan

Mika Huuhtanen

University of Oulu Department of Process and Environmental Engineering P.O. Box 4300 90014 Oulu Finland

Tamao Ishida

Tokyo Metropolitan University Graduate School of Urban Environmental Sciences 1-1 Minami-osawa Hachioji Tokyo 192-0397 Japan and CREST Japan Science and Technology Agency 4-1-8 Hon-cho Kawaguchi Saitama 332-0012 Japan

Freek Kapteijn

Delft University of Technology Chemical Engineering Department Faculty of Applied Sciences Julianalaan 136 2682 BL Delft The Netherlands

Riitta L. Keiski

University of Oulu Department of Process and Environmental Engineering P.O. Box 4300 90014 Oulu Finland

Piotr Kiełbasiński

Polish Academy of Sciences Centre of Molecular and Macromolecular Studies Sienkiewicza 112 90-363 Łódz Poland

Tanja Kolli

University of Oulu Department of Process and Environmental Engineering P.O. Box 4300 90014 Oulu Finland

Narendra Kumar

Åbo Akademi Process Chemistry Centre Industrial Chemistry and Reaction Engineering 20500 Turku/Åbo Finland

Jan J. Lerou

Velocys Inc 7950 Corporate Blvd. Plain City Ohio 43064 USA

Päivi Mäki-Arvela

Åbo Akademi Process Chemistry Centre Industrial Chemistry and Reaction Engineering 20500 Turku/Åbo Finland

Ignacio Melian-Cabrera

University of Groningen Institute of Technology and Management Department of Chemical Engineering Nijenborgh 4 9747 AG Groningen The Netherlands

Jyri-Pekka Mikkola

Åbo Akademi Process Chemistry Centre Industrial Chemistry and Reaction Engineering 20500 Turku/Åbo Finland and University of Umeå Department of Chemistry Technical Chemistry Chemical Biological Centre 90871 Umeå Sweden

Jacob A. Moulijn

Delft University of Technology DelftChemTech Julianalaan 136 2628 BL Delft The Netherlands

Guido Mul

Delft University of Technology DelftChemTech Department Julianalaan 136 2628 BL Delft The Netherlands

Dmitry Murzin

Åbo Akademi Process Chemistry Centre Industrial Chemistry and Reaction Engineering 20500 Turku/Åbo Finland

Norikazu Nishiyama

Osaka University Division of Chemical Engineering Graduate School of Engineering Science 1-3 Machikaneyama Toyonaka Osaka 560-8531 Japan

Satu Ojala

University of Oulu Department of Process and Environmental Engineering P.O. Box 4300 90014 Oulu Finland

Ryszard Ostaszewski

Polish Academy of Sciences Institute of Organic Chemistry Kasprzaka 44-52 01-224 Warsaw Poland

Javier Perez-Ramírez

ETH Zurich Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences HCI E125 Wolfgang-Pauli-Strasse 10 8093 Zurich Switzerland

Eva Pong acz

University of Oulu Thule Institute Centre of Northern Environmental Technology (NorTech Oulu) P.O. Box 4300 90014 Oulu Finland

David W. Rooney

Queen’s University Belfast School of Chemistry and Chemical Engineering Belfast BT9 5AG Northern Ireland UK

Tapio Salmi

Åbo Akademi Process Chemistry Centre Industrial Chemistry and Reaction Engineering 20500 Turku/Åbo Finland

Rutger A. van Santen

Eindhoven University of Technology Department of Chemical Engineering and Chemistry Schuit Institute of Catalysis Laboratory of Inorganic Chemistry and Catalysis Den Dolech 2 5612 AZ Eindhoven The Netherlands

Andrzej Stankiewicz

Delft University of Technology Process & Energy Department Leeghwaterstraat 44 2628 CA Delft The Netherlands

E. Hugh Stitt

Johnson Matthey Technology Centre PO Box 1 Billingham Teeside TS 23 1LB UK

Wiktor Szymański

Warsaw University of Technology Faculty of Chemistry Noakowskiego 3 00-664 Warsaw Poland

Takashi Takei

Tokyo Metropolitan University Graduate School of Urban Environmental Sciences 1-1 Minami-osawa Hachioji Tokyo 192-0397 Japan and CREST Japan Science and Technology Agency 4-1-8 Hon-cho Kawaguchi Saitama 332-0012 Japan

Anna Lee Y. Tonkovich

Velocys Inc 7950 Corporate Blvd. Plain City Ohio 43064 USA

Johan Wärnå

Åbo Akademi Process Chemistry Centre Industrial Chemistry and Reaction Engineering 20500 Turku/Åbo Finland

1

Molecular Catalytic Kinetics Concepts

Rutger A. van Santen

1.1 Key Principles of Heterogeneous Catalysis

We discuss the following topics in the subsequent sections:

Sabatier principle and volcano curve;Brønsted-Evans-Polanyi (BEP) linear activation energy-reaction energy relationships;compensation effect in catalytic kinetics;micropore size dependence in zeolite catalysis;structure sensitivity and insensitivity in transition-metal catalysis;transition-state stabilization rules.

The molecular interpretation of major topics in catalytic kinetics will be highlighted based on insights on the properties of transition-state intermediates as deduced from computational chemical density functional theory (DFT) calculations.

1.2 Elementary Rate Constants and Catalytic Cycle

A catalytic reaction is composed of several reaction steps. Molecules have to adsorb to the catalyst and become activated, and product molecules have to desorb. The catalytic reaction is a reaction cycle of elementary reaction steps. The catalytic center is regenerated after reaction. This is the basis of the key molecular principle of catalysis: the Sabatier principle. According to this principle, the rate of a catalytic reaction has a maximum when the rate of activation and the rate of product desorption balance.

The time constant of a heterogeneous catalytic reaction is typically a second. This implies that the catalytic event is much slower than diffusion (10−6 s) or elementary reaction steps (10−4 − 10−2 s). Activation energies of elementary reaction steps are typically in the order of 100 kJ mol−1. The overall catalytic reaction cycle is slower than elementary reaction steps because usually several reaction steps compete and surfaces tend to be covered with an overlayer of reaction intermediates.

Clearly, catalytic rate constants are much slower than vibrational and rotational processes that take care of energy transfer between the reacting molecules (10−12 s). For this reason, transition reaction rate expressions can be used to compute the reaction rate constants of the elementary reaction steps.

Eyring’s transition-state reaction rate expression is

(1.1a)

(1.1b)

Q# is the partition function of transition state and Q0 isthepartitionfunctionof ground state, k is Boltzmann’s constant, and h is Planck’s constant.

The transition-state energy is defined as the saddle point of the energy of the system when plotted as a function of the reaction coordinates illustrated in Figure 1.1.

Figure 1.1 Transition-state saddle point diagram. Schematic representation of potential energy as a function of reaction coordinate.

Γ is the probability that reaction coordinate passes the transition-state barrier when the system is in activated state. It is the product of a dynamical correction and the tunneling probability. Whereas statistical mechanics can be used to evaluate the pre-exponent and activation energy, Γ has to be evaluated by molecular dynamics techniques because of the very short timescale of the system in the activated state. For surface reactions not involving hydrogen, Γ is usually close to 1.

Most of the currently used computational chemistry programs provide energies and vibrational frequencies for ground as well as transition states.

A very useful analysis of catalytic reactions is provided for by the construction of so-called volcano plots (Figure 1.2). In a volcano plot, the catalytic rate of a reaction normalized per unit reactive surface area is plotted as a function of the adsorption energy of the reactant, product molecule, or reaction intermediates.

Figure 1.2 Volcano plot illustrating the Sabatier principle. Catalytic rate is maximum at optimum adsorption strength. On the left of the Sabatier maximum, rate has a positive order in reactant concentration, and on the right of Sabatier maximum the rate has a negative order.

A volcano plot correlates a kinetic parameter, such as the activation energy, with a thermodynamic parameter, such as the adsorption energy. The maximum in the volcano plot corresponds to the Sabatier principle maximum, where the rate of activation of reactant molecules and the desorption of product molecules balance.

1.3 Linear Activation Energy-Reaction Energy Relationships

The Sabatier principle deals with the relation between catalytic reaction rate and adsorption energies of surface reaction intermediates. A very useful relation often exists between the activation energy of elementary surface reaction steps, such as adsorbate bond dissociation or adsorbed fragment recombination and corresponding reaction energies. These give the Brønsted-Evans-Polanyi relations.