Hydroisomerization of n -heptane over Pt-loaded USY zeolites. Effect of steaming, dealumination, and the resulting structure on catalytic properties

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Abstract

The hydroconversion of n-heptane was studied on five USY zeolite samples loaded with 1 wt % Pt. Experiments were performed on a continuous fixed-bed stainless steel reactor at 210-310 °C and pressures up to 15 bar. Three in-house samples were subjected to steaming treatment, and the remaining were acid-leached from a commercial source. The study aimed to evaluate the effect of acid leaching, and its subsequent extraframework alumina (EFAL) species removal, on the performance of bifunctional USY zeolite catalysts during n-heptane transformation. Results have shown that steamed samples generate more cracked products at higher conversions when compared to acid-leached ones, more than likely due to a high presence of EFAL species. The degree of steaming played a role in decreasing cracking tendency at higher pressures, which is attributed to pore structure change and decreasing acidity. In addition, steaming resulted in a catalyst sample capable of generating isomers with blended research octane numbers close to those achieved with a robust commercial catalyst. However, poisoning experiments have shown that these two catalysts are highly sensitive to sulfur and require sulfur-free feeds in order to demonstrate their full capacities. © 2011 American Chemical Society.

Bibliographical metadata

Original languageEnglish
Pages (from-to)9918-9924
Number of pages6
JournalIndustrial and Engineering Chemistry Research
Volume50
Issue number17
DOIs
Publication statusPublished - 7 Sep 2011