Linking microalgae characteristics with their fast pyrolysis products

This study investigated the relationships between microalgal characteristics, reaction temperature, and pyrolysis products using eight microalgal species. Proximate, ultimate, and biochemical analyses were conducted to characterize these microalgae. Fast pyrolysis was performed in a Pyroprobe® coupled to a two-dimensional gas chromatograph and a time-of-flight mass spectrometer at 450–650 °C. The solid residues ranged from 14.9–59.1 % across all pyrolysis tests. The experimental dataset comprised 24 instances with 27 features, including microalgal composition, temperature, biochar yield, and product composition. Multivariate analyses were employed to interpret this dataset, including Pearson correlation analysis, principal component analysis (PCA), and canonical correlation analysis (CCA). Pearson correlation analysis showed biochar yields positively correlated with ash and moisture contents and negatively with volatile matter; proteins exhibited the highest charring tendency. PCA identified species-specific product patterns, e.g., Arthrospira (Limnospira) platensis was linked to nitrogenates and aromatics, while Odontella aurita produced sulfur compounds despite moderate sulfur content. PCA also indicated that oxygen and lipids were not key to aromatic formation. CCA revealed that the strong correlation between pyrolysis temperature and aromatics was partly due to protein content and highlighted a distinct link between chlorophyll content and alcohol production. Overall, this work highlights the potential of innovative microalgae as feedstocks for fast pyrolysis and emphasizes the utility and potential of multivariate tools for interpreting complex experimental datasets.