Desenvolvimento de catalisadores Pt-USY para melhorar o índice de cetano em frações de diesel de baixa qualidade mediante a reação de abertura seletiva de anéis de compostos Naftênicos

Abstract

A challenging hot topic faced by the oil refinery industry is the upgrading of low-quality distillate fractions, such as LCO, in order to meet current quality standards for diesel fuels. Thereof, an auspicious technological alternative entails the complete saturation of the aromatic structures followed by the selective cleavage of endocyclic C-C bonds in the formed naphthenic rings (selective ring opening or SRO). This work reports the influence of metal incorporation method in bifunctional Pt-USY catalysts with the aim of maximizing the dispersion at relatively high metal loadings as a means of improving their performance for the SRO of decalin as a model feed. High performance Pt-USY catalysts (4.9Pt-NaUSY-im3 and 4.8Pt-NaUSYTPA-im3) have been developed for the selective ring opening of decalin (model molecule, representing naphthenic compounds) by increasing the cetane index of the reaction products mixture. The 4.8Pt-NaUSYTPA-im3 catalyst presented a yield of 28.0 wt% to OCD (33.2% selectivity), of 53.8 wt% to ROP + OCD sum (63.7% selectivity) and a yield 26.0 wt% to light hydrocracking products (30.7% selectivity). The 4.9Pt-NaUSY-im3 catalyst presented an OCD yield of 17.8 wt% (22.0% selectivity), an ROP + OCD yield of 44.2 wt% (selectivity 54.8%) and a yield to light hydrocracking products of 31.1 wt% (selectivity 38.5%). The secondary mesoporosity of the 4.8Pt-NaUSYTPA-im3 catalyst had a positive effect on the catalyst performance with respect to decalin ring opening products (ROP and OCD), while maintaining lower yields for light hydrocracking products (C9-) compared to the 4.9PtNaUSY-im3 catalyst. Thus, (i) low Brønsted acidity, (ii) high amount of platinum - metal function, (iii) three-dimensional pore size zeolite, (iv) secondary mesoporosity, especially for the 4.8Pt-NaUSYTPA-im3 catalyst and (v) high hydrothermal stability make these catalytic systems very promising.