ESTUDO DA INTERAÇÃO METAL-SUPORTE EM CATALISADORES DE RUTÊNIO PROMOVIDOS POR BÁRIO E CÉSIO PARA A SÍNTESE DE AMÔNIA / THE STUDY OF METAL-SUPPORT INTERACTION ON BARIUM AND CESIUM PROMOTED RUTHENIUM CATALYSTS FOR THE AMMONIA SYNTHESIS

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The industrial ammonia synthesis process uses a triple promoted iron catalyst, operating at drastic temperature conditions between 673K and 973K, and high pressure (300atm). New catalysts have been studied, replacing iron, to increase NH3 production. The main advantage of Ru-based catalysts is that they are less sensitive to poisoning by ammonia than Fe-based catalysts. The aim of this work was to evaluate ruthenium catalysts supported on zeolites and hydrotalcite promoted by basic cations for ammonia synthesis reaction. The influence of the support type on the ruthenium catalysts and of introduction way of the ruthenium precursors was verified. Also the hole of the cationic promoters (Ba and Cs) on the metal-support interaction and on the ruthenium catalysts activity in the ammonia synthesis reaction was examined. The ruthenium catalysts supported on hydrotalcite had the highest conversion in the ammonia synthesis reaction. They presented the highest degrees of dispersion and reduction of metallic particles. The barium, despite having decreased the interaction between the ruthenium and the support, showed to be a more effective promoter on the synthesis of ammonia than the cesium. The barium introduction order resulted in different effects over the ruthenium catalysts performance depending on the support. The impregnation method with ruthenium carbonil was the most effective, leading to more basic ruthenium catalysts and more actives in the ammonia synthesis reaction.

ASSUNTO(S)

catalisadores de rutenio metal-support interaction ammonia synthesis interacao metal-suporte ruthenium catalysts sintese de amonia

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