Advances In Catalyst Deactivation

This book is a printed edition of the Special Issue "Advances in Catalyst Deactivation" that was published in Catalysts

Most catalysts used in the chemical and petrochemical indus tries are strongly affected by one or another form of deactivation, leading to poor performances and reduced life. The increasing num ber of scientific communications devoted to the subject in recent years, and culminating with an International Symposium held in Antwerp in October 1980, is a measure of the interest it arouses in both the industrial and academic communities. A stage has been reached whereby it was thought that a NATO Advanced Study Institute on "Catalyst Deactivation" might be fruit ful in establishing the state of the art and in stimulating a more systematic research on the phenomenon. Such a meeting was held ~n Lagos, Portugal, from 18 to 29 May 1981. The purpose of the Institute was to present and discuss in a didatic and systematic way the various processes that lead to cata lyst deactivation, namely coking, poisoning and solid state trans formations, and at the same time to promote the exchange of ideas and experiences among the participants, drawn from industry and uni versity. The lectures presented at the Institute are collected in this volume with the exception of Dr. L.L.Hegedus "Catalyst Poisoning", which has been previously published (Catalysis Reviews, Science md Engineering, 23, 377-476, 1981).

Deactivation and Poisoning of Catalysts presents the most current research in the area of heterogeneous catalysis. It focuses on the chemically induced effects associated with bonded surface species that cause catalyst activity decline -- and in some cases a change in catalyst specificity. In addition, this volume examines poisoning of dispersed metal catalysts ... the thermodynamics of sulfur-metal and carbon-metal interactions ... model poisoning reactions on single crystals ... deactivation in petroleum refining and petrochemical processes ... coking of metal catalysts ... and more. The new approaches and solutions to catalyst deactivation and poisoning presented in this guide are invaluable to all heterogeneous catalysis specialists, including chemical and petroleum engineers, and surface, synthetic, physical, and industrial chemists. Book jacket.

In chemical processes, the progressive deactivation of solid catalysts is a major economic concern and mastering their stability has become as essential as controlling their activity and selectivity. For these reasons, there is a strong motivation to understand the mechanisms leading to any loss in activity and/or selectivity and to find out the efficient preventive measures and regenerative solutions that open the way towards cheaper and cleaner processes. This book covers the fundamental and applied aspects of solid catalyst deactivation in a comprehensive way and encompasses the state of the art in the field of reactions catalyzed by zeolites. This particular choice is justified by the widespread use of molecular sieves in refining, petrochemicals and organic chemicals synthesis processes, by the large variety in the nature of their active sites (acid, base, acid-base, redox, bifunctional) and especially by their peculiar features, in terms of crystallinity, structural order and textural properties, which make them ideal models for heterogeneous catalysis. The aim of this book is to be a critical review in the field of zeolite deactivation and regeneration by collecting contributions from experts in the field which describe the factors, explain the techniques to study the causes and suggest methods to prevent (or limit) catalyst deactivation. At the same time, a selection of commercial processes and exemplar cases provides the reader with theoretical insights and practical hints on the deactivation mechanisms and draws attention to the key role played by the loss of activity on process design and industrial practice./a

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.

Most catalysts used in the chemical and petrochemical indus tries are strongly affected by one or another form of deactivation, leading to poor performances and reduced life. The increasing num ber of scientific communications devoted to the subject in recent years, and culminating with an International Symposium held in Antwerp in October 1980, is a measure of the interest it arouses in both the industrial and academic communities. A stage has been reached whereby it was thought that a NATO Advanced Study Institute on "Catalyst Deactivation" might be fruit ful in establishing the state of the art and in stimulating a more systematic research on the phenomenon. Such a meeting was held ~n Lagos, Portugal, from 18 to 29 May 1981. The purpose of the Institute was to present and discuss in a didatic and systematic way the various processes that lead to cata lyst deactivation, namely coking, poisoning and solid state trans formations, and at the same time to promote the exchange of ideas and experiences among the participants, drawn from industry and uni versity. The lectures presented at the Institute are collected in this volume with the exception of Dr. L.L.Hegedus "Catalyst Poisoning", which has been previously published (Catalysis Reviews, Science md Engineering, 23, 377-476, 1981).

Catalyst Deactivation 1991 was an expanded version of earlier, highly successful symposia. The symposium featured invited and solicited papers including 4 plenary lectures, 78 oral presentations and 23 poster papers. Most of the papers are contained in this volume. The eight main topics emphasised at this most recent symposium were: deactivation mechanisms/phenomena (carbon deposition, poisoning, and sintering), methods (modeling and techniques), and important catalysts (hydrotreating, oxides, and zeolites). All of these areas were well represented as attested by the substantial number of papers contained in these proceedings. Four review papers based on the plenary lectures provide state-of-the-art perspectives on new thrusts in deactivation research and development.