Abstract The presence of coke on catalysts related to the processes of Fluid Catalytic Cracking and Biomass Catalytic Upgrading of pyrolysis vapors can lead to a problematic operation and the eventual deactivation and replacement of these catalysts. To this end, the kinetics of coke combustion was investigated by two different methods in ZSM-5 catalysts: Temperature-Programmed Oxidation (TPO) and Thermogravimetric analysis (TGA). The experiments were conducted in the temperature range of 500—750 °C, using air for the combustion reactions. The catalysts were coked by different processes: Fluid Catalytic Cracking (FCC) and Biomass Catalytic Upgrading Pyrolysis Vapors (CUPV), in order to form different types of coke, with a carbon content of 3 mass%. The results revealed that the carbon combustion of the coked catalyst from the FCC unit (HC-coked) was faster than that of the CUPV (BIO-coked) unit in the low-medium temperature area (500—650 °C). Increasing the combustion temperature (T > 650 °C) reduced the difference in combustion rates between the two coked samples, resulting in similar values at 750 °C. The calculated activation energy for the BIO-coked catalyst was higher than that of HC-coked catalyst denoting that coke combustion proceeds much easier in FCC conditions. It is worth noting, that the final conclusions and kinetics analysis from both techniques (TGA and TPO) were in perfect agreement.
Pachatouridou et al. (Fri,) studied this question.