Assessment of pyrolytic algal oil as a sustainable alternative lubricant base oil

Abstract

Purpose This study aims to investigate the potential of algal oil as a bio-derived alternative to commercial lubricant base oil by analyzing its chemical composition, rheological properties and structural characteristics validated by functional analysis. Design/methodology/approach Algal oil, produced via pyrolysis under optimized conditions, was compared with commercial synthetic lubricants through Fourier Transform Infrared Spectroscopy and the spectrum was interpreted using Principal Component Analysis. Rheological analysis was conducted across a range of temperatures (−5°C to 55°C) and shear rates (0.01 s−1 to 100 s−1) to evaluate viscosity variations. Oscillatory tests determined viscoelastic transitions. Differential Scanning Calorimetry (DSC) assessed thermal stability. Gas Chromatography - Mass Spectrometry (GC-MS) provided a detailed compositional profile, where Nuclear Magnetic Resonance (NMR) confirmed the molecular structure, bonding and functional groups. Functional performance was validated by a tribological test. Findings The algal oil exhibited stable viscosity at higher temperatures and increased viscosity at lower temperatures. Oscillatory tests indicated a transition from liquid-like to solid-like behavior as the stress frequency increased, highlighting its viscoelastic properties. DSC analysis revealed its stability, having a glass transition temperature at −12.2°C. GC-MS confirmed the presence of fatty acids like myristic acid, palmitic acid and stearic acid, indicating a balance of stability and fluidity. NMR confirmed the presence of fatty acids and triglycerides, as indicated by prominent peaks at 1.2 and 2.1 ppm, showcasing its similarity to base oils used for lubricant manufacturing. Tribological testing demonstrated a significant reduction in wear loss. Originality/value This study presented a novel approach for developing bio-lubricant by using pyrolysis-derived algal oil as an alternative to petroleum-based base oils.