Material Recycling of Contaminated Waste Wood by Fast Pyrolysis Technology

Abstract Approximately 50 Mtons of waste wood is produced annually in the European Union (EU) alone, but its current primary use is combustion for heat and power production. Now, the recycling industry needs to find alternative ways to process waste wood to meet demands for increased material recovery rates for all type of wastes to meet the 2030 and 2050 emission goals of the Paris Agreement. Pyrolysis is a promising technique to this end, capable of converting biomass into biocarbon, bio-oil, and carbonaceous gases. The present work evaluates the potential for valorizing a low-cost mixture of treated and untreated waste wood via fast pyrolysis (FP) and zeolite-catalyzed fast pyrolysis (CFP). A total of 34% and 20% of the carbon was recovered as biocarbon with FP and CFP, respectively. Both processes yielded organic condensates (bio-oils) corresponding to 28% of the carbon content, although they differed in chemical composition: FP produced a more oxygen-rich bio-oil possibly suitable as a binder, while CFP yielded a more upgraded bio-oil with a lower oxygen content, making it a suitable feedstock for production of arene-based biochemicals. Overall, the results indicate that contaminated waste wood can be valorized via pyrolysis for increased material recycling, and that such waste wood represents a promising low-cost alternative to virgin wood feedstocks.