Estimation of toxic coke deposits on fresh and regenerated Pt/Al2O3 catalyst from methylcyclopentane reforming in H2 and N2 atmospheres

An estimate of the quantity of toxic coke deposited on fresh and regenerated Pt/Al2O3 catalyst has been determined for methylcyclopentane (MCP) reforming in a Berty CSTR at 390 degrees C, W/F=0.11g min cm(-3), total pressure of 1 atm and MCP partial pressure of 9.2 x 10(-2) atm in H-2 or N-2 carrier. Eleven cycles consisting each of catalyst deactivation, regeneration and reduction were investigated with 3 in H-2 and 8 in N-2. Oxidizable (primary) coke deposits were higher in N-2. However, higher levels of toxic (secondary) coke were deposited in H-2. The ratio of oxidizable to toxic coke lies between 1-15x10(3) in H-2 and 22 - 55 x 10(3) in N-2. The coke-time profiles for secondary coke removal exhibited maxima suggestive of three types of secondary coke with varying reactivity in H-2. Furthermore, the results strongly suggest that the cokes were layered on acidic coke forming sites with the solid phase transformation of primary to secondary coke occurring at the catalyst-coke interface.