Catalyst deactivation in catalytic fast pyrolysis of forest biomass

Inside the European Union, the policy-driven demand for renewable fuels has opened up promising new opportunities for the valorization of forest biomass. This can be seen as one potential renewal pathway for the traditional forest industry. Diversification of the product portfolio to include more highly refined energy products, e.g. transportation fuels, is an approach that is already being pursued by some companies. Among the various conversion technologies, fast pyrolysis has been identified as a straightforward method for converting solid biomass into a liquid fuel, pyrolysis oil. However, due to its challenging physicochemical properties, pyrolysis oil requires upgrading before it can be used as a transportation fuel. The severity of the upgrading can be reduced by introducing a catalyst directly into the pyrolysis process. With this approach, which is known as catalytic fast pyrolysis (CFP), the primary biomass decomposition reactions are followed by secondary catalytic reactions taking place within the pyrolysis reactor. This results in a trade-off, where quality of the pyrolysis oil improves at the expense of the oil yield. Catalyst deactivation has been identified as a key parameter that affects the overall performance of the CFP process. This presentation will cover catalytic fast pyrolysis research that been carried out at VTT Technical Research Centre of Finland, with a special emphasis on catalyst deactivation. Various deactivation phenomena that have been observed in bench-scale experiments and in an extended pilot-scale experiment will be discussed.