Conversion of Contaminated Biomass in an innovative Biorefinery into High-Quality Energy Carriers

Within the European-funded research project "Phy2Climate," an innovative biorefinery was implemented with the overall goal of combining phytoremediation and biofuel production. In the biorefinery, heavy metal-contaminated biomass harvested from the project’s pilot sites was initially converted into gaseous, liquid, and solid intermediate products using the thermo-catalytic reforming process (TCR®). The aim of this study is to investigate the feasibility of converting heavy metal contaminated biomass (Rapeseed and Quinoa) into high-quality energy carriers using TCR® technology at post-reformer temperatures ranging from 550°C to 750°C. The results showed that increasing post-reformer temperatures significantly influenced product yields and quality. Lower temperatures favored the formation of bio-oil and bio-coke (commonly also referred to as biochar), while higher temperatures increased pyrolysis gas production, shifting the main energy carrier from bio-coke to gas. Heavy metal distribution varied: for Rapeseed, most heavy metals accumulated in bio-coke at 550°C, while for Quinoa, heavy metals were concentrated in bio-coke at 750°C. Higher temperatures resulted in higher H2 yields and better HHV for both biomasses, with bio-oil with better HHV meeting ISO 8217 (2017) standards for low sulfur fuel oil. The study highlights a trade-off between maximizing favored product yields and concentrating heavy metals in bio-coke, suggesting further research to optimize TCR® processing conditions.