COBALT SUPPORTED ON ZSM-5 ZEOLITE USING KAOLIN AS SILICON AND ALUMINUN SOURCES FOR FISCHER-TROPSCH SYNTHESIS

Abstract

The use of clay as an alternative source of raw material provides economic routes for the synthesis of ZSM-5. Therefore, the main purpose of this work was to study ZSM-5 synthesis using kaolin as Si and Al source. The zeolite using kaolin as a source of silica and aluminum has been applied as support for a 20wt% Co catalyst. Zeolite ZSM-5 was obtained with kaolin under hydrothermal synthesis at 373K for 48 hours. The kaolin was submitted to heat treatment at 973K for 2 hours before being used in synthesis. The deposition of cobalt on the support ZSM-5CK was performed by means of wet impregnation, using a 0.1-M aqueous solution of cobalt nitrate. The catalytic support and metal-loaded catalyst have been characterized and evaluated for the Fischer-Tropsch Synthesis (FTS) under controlled conditions (T = 593K, P = 20atm, H2:CO molar ratio = 2) in a fixed bed reactor for 150 hours. From the Temperature Programmed Reduction profiles, two reduction peaks were observed at 629K and 677K, corresponding to the stepwise reduction of Co3O4 particles to CoO and then to metallic Co on the support external surface. It was observed with the FTS results that the 20wt% Co/ZSM-5CK catalyst yielded a 10% conversion rate and high selectivity towards the production of C5+ (98%).