Ammonia Synthesis Catalysts

This book provides a review of worldwide developments in ammonia synthesis catalysts over the last 30 years. It focuses on the new generation of Fe1-xO based catalysts and ruthenium catalysts - both are major breakthroughs for fused iron catalysts. The basic theory for ammonia synthesis is systematically explained, covering topics such as the chemical components, crystal structure, preparation, reduction, performance evaluation, characterization of the catalysts, the mechanism and kinetics of ammonia synthesis reaction. Both theory and practice are combined in this presentation, with emphasis on the research methods, application and exploitation of catalysts. The comprehensive volume includes an assessment of the economic and engineering aspects of ammonia plants based on the performance of catalysts. Recent developments in photo-catalysis, electro-catalysis, biocatalysis and new uses of ammonia are also introduced in this book. The author, Professor Huazhang Liu, has been engaged in research and practice for more than 50 years in this field and was the inventor of the first Fe1-xO based catalysts in the world. He has done a lot of research on Fe3O4 based- and ruthenium based-catalysts, and has published more than 300 papers and obtained 21 patents during his career.

The phenomenon of catalysis is found in many homogeneous and heterogeneous systems undergoing chemical change, where it effects the rates of approach to the equilibrium state in processes as diverse as those found in the stars, the earth's mantle, living organisms, and the various chemistries utilized by industry. The economies and the living standards of both developed and developing countries depend to varying degrees upon the efficacy of their chemical industries. Con sequently, this century has seen a wide exploration and expansion of catalytic chemistry together with an intensive investigation of specific, essential processes like those contributing to life-supporting agricultures. Prime among the latter must surely be the "fixation" of atmospheric nitrogen by catalytic hydrogenation to anhydrous ammonia, still the preferred synthetic precursor of the nitrogenous components of fertilizers. In each decade contemporary concepts and techniques have been used to further the understanding, as yet incomplete, of the catalyst, the adsorbates, the surface reactions, and the technology of large-scale operation. The contributors to the present volume review the state of the art, the science, and the technology; they reveal existing lacunae, and suggest ways forward. Around the turn of the century, Sabatier's school was extending the descriptive catalytic chemistry of hydrogenation by metals to include almost all types of multiple bond. The triple bond of dinitrogen, which continued to be more resistant than the somewhat similar bonds in carbon monoxide and ethyne, defied their efforts.

Ammonia is one of the 10 largest commodity chemicals produced. The editor, Anders Nielsen, is research director with one of the largest industrial catalyst producers. He has compiled a complete reference on all aspects of catalytical ammonia production in industry, from thermodynamics and kinetics to reactor and plant design. One chapter deals with safety aspects of ammonia handling and storage.

Plasma catalysis is gaining increasing interest for various gas conversion applications, such as CO2 conversion into value-added chemicals and fuels, N2 fixation for the synthesis of NH3 or NOx, methane conversion into higher hydrocarbons or oxygenates. It is also widely used for air pollution control (e.g., VOC remediation). Plasma catalysis allows thermodynamically difficult reactions to proceed at ambient pressure and temperature, due to activation of the gas molecules by energetic electrons created in the plasma. However, plasma is very reactive but not selective, and thus a catalyst is needed to improve the selectivity. In spite of the growing interest in plasma catalysis, the underlying mechanisms of the (possible) synergy between plasma and catalyst are not yet fully understood. Indeed, plasma catalysis is quite complicated, as the plasma will affect the catalyst and vice versa. Moreover, due to the reactive plasma environment, the most suitable catalysts will probably be different from thermal catalysts. More research is needed to better understand the plasma–catalyst interactions, in order to further improve the applications.

This book presents sustainable synthetic pathways and modern applications of ammonia. It focuses on the production of ammonia using various catalytic systems and its use in fuel cells, membrane, agriculture, and renewable energy sectors. The book highlights the history, investigation, and development of sustainable pathways for ammonia production, current challenges, and state-of-the-art reviews. While discussing industrial applications, it fills the gap between laboratory research and viable applications in large-scale production.

Ammonia is one of the most important inorganic basic chemicals, not only for the manufacture of fertilizers (85%) but also for the production of plastics, fibers, explosives, and intermediates for dyes and pharmaceuticals. It is an essential reaction component for the synthesis of numerous organic chemicals used as solvents and intermediates. The book provides a practical and up-to-date account of the product properties, synthesis and reaction mechanisms, including catalysis and commercial catalysts, modern production technology for different feedstocks, quality specifications and environmental health and safety aspects, uses and economic data of this important commodity chemical. It also discusses perspectives of future developments of commercial ammonia production. Over 1400 references to the relevant literature complete this concise presentation, whose aim is to inform the reader of the present status of the theory and practice of industrial ammonia production. Chemical engineers, engineers and chemists in industry, engineering companies, catalyst manufacturers, equipment makers and chemical engineering university departments will certainly profit from this comprehensive review based on the author's long practical experience in a leading technical management position of one of the largest European ammonia producers.