High Yields of LPG Via n-Hexane Hydrocracking Using Unloaded Acidic Zeolite Catalysts

This work includes investigating the hydrocracking of n-hexane, as a low-octane naphtha component to high-octane gaseous motor fuel (LPG) in a pulse flow atmospheric microreactor using untreated and steam-treated H-MOR, H-BEA, or H-ZSM-5 zeolite catalysts. All zeolites were metal-free and their bifunctionality depended only on the Bronsted zeolitic acid sites. The temperature programmed desorption analysis was performed to compare the weak and strong acid sites in the current catalysts. The catalytic activities of the catalysts were found to correlate well with their acid strengths. The most active catalyst was St-H-MOR, which acquired the strongest acid sites and highest densities. On this catalyst, 92.1% LPG was produced at 350°C, whereas on the un-steamed one (H-MOR), the LPG yield amounted to 88.0% at the same temperature. Maximum LPG production on H-BEA acquired 84.6% at 400°C, whereas on St-H-BEA, it acquired a close yield (85.7%). Zeolites H-ZSM-5 and St-H-ZSM-5 acquire very low catalytic activitie...