Corrosion-induced changes in bio-oil aging: A gas chromatography exploration

Understanding the interactions between metals, corrosion products, and bio-oil (BO) is crucial for safe and efficient BO operations. This study explored BO aging and BO + steel (carbon steel (CS) and stainless steel (SS)) immersion at 80 °C for 168 h, alongside experiments adding synthetic Fe2O3 and Cr2O3 powders to BO. Gas generated was analyzed via gas chromatography (GC). Results showed 80 °C was an optimal pre-heating temperature for BO without gas evolution. BO aging at up to 220 °C for 24 h increased CO2 and CO evolutions. CS immersion at 80 °C produced more H2 and CO2 than those at 50 °C, due to higher corrosion rates. The BO + Fe2O3 trial released less H2 but more CO2 compared to BO + CS immersion, due to internal BO reactions catalyzed by Fe2O3. BO + SS304L and BO + Cr2O3 trials showed similar H2 and CO2 production, highlighting the catalytic effect of Cr2O3. Leached Fe ions in BO formed chelate complexes with organic compounds, causing phase separation. These findings have significant implications for producing renewable biofuels via BO co-processing operations by emphasizing the need to optimize preheating temperatures, validate the compatibility of construction materials, and implement safety measures to mitigate gas accumulation risks.