Chemical optimum component” procedure

The above procedures for catalyst preparation have generally provided excellent results. Especially important are surface-sensitive reactions. With supported catalysts in which the active components have a narrow particle-size distnbution, the optimum particle size for a demanding reaction can be established. Major improvements of supported catalysts, e.g. with respect to carbon deposition and ammonia decomposition, can be achieved by preparing catalysts with a narrow par-ticle-size distribution. Also, the preparation of catalysts in which the active components have a uniform chemical composition is highly important One instance is the preparation of supported vanadium oxide phosphorus oxide (VPO) catalysts for the selective oxidation of w-butane to maleic anhydride, which has been carried out using vanadium(III) deposition onto silica [31]... 

The chemical composition and the structure of the contamination layer oxides in the primary systems depend highly on the reactor type (PWR, BWR) and also on the operational history of the plant. The optimum decontamination process to be applied, therefore, must be selected and, if necessary, optimized to meet the task in question. In particular, when components and systems are to be decontaminated, different structural materials and, consequently, oxide layers of different composition are involved, resulting in more stringent demands on the decontamination procedures to be applied. 

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