Activation, Deactivation, and Poisoning of Catalysts

1st Edition - January 1, 1988
Author: John Butt
Language: English
eBook ISBN:
9 7 8 - 0 - 3 2 3 - 1 4 0 8 6 - 7

Activation, Deactivation, and Poisoning of Catalysts deals with the circumstances and mechanisms underlying catalyst activation, deactivation, and poisoning. The emphasis is on the… Read more

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Activation, Deactivation, and Poisoning of Catalysts deals with the circumstances and mechanisms underlying catalyst activation, deactivation, and poisoning. The emphasis is on the techniques for handling deactivating systems, not on results per se. Deactivation by fouling and sintering is given consideration. This book is organized into three sections and consists of 12 chapters. The first part is devoted to a systematic development of the manner in which catalysts are activated, deactivated, poisoned, and in some cases reactivated on a microscopic basis. The first chapter explains the concept of the active center as utilized in catalysis, along with catalyst regeneration, rejuvenation, and detoxification. In the second part, the reader is introduced to the problem of heat transfer as well as the transport of reactants and products in the interior of the particle coupled with chemical reaction therein. The macroscopic deactivation behavior of the catalyst particle is described in terms of fundamental kinetic deactivation phenomena and of parameters governing heat and mass transfer. The last part is primarily concerned with a collection of catalyst particles within the reactor, with emphasis on the global activity of the reactor. In the last chapter, a pragmatic approach is presented to predict the design and performance of chemical reactors containing a deactivating catalyst. This book is written for catalytic chemists, researchers, reactor designers, and students interested in catalyst activation, deactivation, and poisoning.

Preface

I Deactivation of Catalytic Surfaces: Microscopic Processes

1 Physical and Chemical Description of Deactivation

I. The Concept of the Active Center as Utilized in Catalysis

II. Operational Definitions of Deactivation

III. Regeneration, Rejuvenation, and Detoxification

IV. Summary—Conventional Wisdom and Other Matters

V. More Definitions

References

2 Mathematical Description of Deactivating Systems

I. Deactivation of Systems Having a Single Main Reaction

II. Phenomenological Description of Catalyst Deactivation

III. Comments on Obtaining Deactivation Data: Experimentation

IV. Summary and Evaluation

References

3 Deactivation by Fouling

I. Coke Formation and Fouling Kinetics

II. Chemistry of Coke Formation

III. Coke Distribution in Catalyst Pores

IV. Mechanism of Fouling

V. Fouling of Reforming Catalysts

VI. Summary and Evaluation

References

4 Deactivation by Poisoning

I. Some Beginning Ideas: A General Discussion

II. Poisoning of Non Uniform Surfaces: True and Apparent

III. Some Studies of Homogeneous Surfaces

IV. Heterogeneous Surfaces: Site Strength Distributions

V. Particle Size Dependence

VI. Multifunctional Catalysts

VII. Summary and Evaluation

References

5 Deactivation by Sintering

I. Sintering in Supported Metal Systems

II. Particle Growth Models

III. Crystallite Splitting and Redispersion

IV. Metal-Support Interaction Effects on Sintering and Redispersion

V. Summary and Evaluation

References

II Deactivation of Catalyst Pellets: Macroscopic Processes

6 The Time Scale of Deactivation in Pelleted Catalysts

I. General Formulation of the Problem

II. Some Aspects of the General Solution

References

7 Intraparticle Deactivation

I. Limiting Types of Deactivation in Pellets

II. Modeling the Deactivation of Pellets

III. Nonuniform Distribution of Catalytic Materials in Pellets

IV. Fouling of Hydrodesulfurization Catalysts

V. Summary and Evaluation

References

8 Direct Measurement of Reaction Nonuniformity in Catalyst Pellets

I. The Single-Pellet Diffusion Reactor: Concentration Measurements

II. The Single-Pellet Diffusion Reactor: Temperature Measurements

III. Summary and Evaluation

References

9 Regeneration of Coked Particles

I. Reactions of Coke with Hydrogen and Oxygen

II. The Intraparticle Problem

III. Summary and Evaluation

References

III Deactivation in Chemical Reactors: Global Processes

10 Deactivation in Fixed Beds

I. Activity Distributions in Fixed Beds—A Snapshot

II. Moving Reaction Zones—Theoretical Development for Isothermal Reactors

III. Moving Reaction Zones—Theoretical Development for Non Isothermal Reactors

IV. Some Experimental Results—Isothermal Reactors

V. Scale-up to a Nonisothermal Industrial Reactor

VI. Catalyst Poisoning and Non Isothermal Fixed-Bed Reactor Dynamics

VII. Constant-Conversion Operation

VIII. Summary and Evaluation

References

11 Regeneration of Fixed Beds

I. Regeneration as a Deactivation Problem in Reverse

II. Some Quantitative Studies

III. Summary—Deactivation in Reverse

References

12 A Case History: Kinetic Lumping, Deactivation, and Reactor Models for Catalytic Cracking

I. Kinetic Lumping and Deactivation

II. Reactor Models—Fixed, Moving, and Fluidized Beds

III. Reaction Kinetics and Model Evaluation

IV. Some Comparisons of Reactor Performance

V. Another Optimization Problem

VI. Effects of Deactivation on Selectivity

VII. Some Feedstock Correlations

VIII. Summary Remarks

References

Index