Supercritical water gasification of palmitic acid: Products, pathway and kinetics

In this study, palmitic acid was selected as a representative model compound for fatty acids to examine the product distribution during the supercritical water gasification (SCWG) process. The degradation of PA was found to follow first-order reaction kinetics, with an activation energy of 155 ± 14 kJ mol⁻¹. At 450 °C, CO₂ emerged as the predominant gaseous product, whereas CH₄ became the primary gaseous product as the temperature increased to 510 °C. The main liquid intermediates formed during the SCWG of palmitic acid include 1-alkenes (C₉-C₁₄) and pentadecane. Two major reaction pathways were identified for the conversion of palmitic acid in supercritical water: thermal cracking, which leads to the formation of volatile fatty acids and 1-alkenes (C₉-C₁₄), and decarboxylation, which results in the production of pentadecane and CO₂.