The development of the remarkable iron catalyst and the technology for the synthesis of ammonia from nitrogen and hydrogen by Haber and Bosch in the early years of this century provided an economic means of fixing nitrogen in large quantities for the first time. The invention and continuing refinement of the six other catalysts for hydrogen manufacture has permitted the production of the necessary cheap synthesis gas and together with the design of sophisticated compressors and materials of construction has led to an industrial process which is so efficient that it begins to approach what is thermodynamically the limit. The understanding of the chemical processes, and the integration of these with the heat recovery system and mechanical design of the plant has led to a method for fixing nitrogen that is exceptionally efficient.
The seven catalysts used in the process demonstrate many aspects of the art and science of the catalyst designer and manufacturer: they must be active and yet robust, long lived and yet cheap. This paper describes these catalysts, and considers in particular the characteristics which are important to good performance in the plant.
J D Rankin, Catalysts and Chemicals Group, Research and Development Department, Agricultural Division, Imperial Chemical Industries Ltd, UK.
31 pages, 14 figures, 9 references