Transformation of residual fatty raw materials into third generation green diesel over a nickel catalyst supported on mineral palygorskite

Abstract The transformation of residual fatty raw materials (RFRMs) (waste cooking oils (WCO), fatty acid distillate (FAD), oil extracted from spent coffee grounds (SCGO) and oil from chicken fat (CHO)) into third generation green diesel was studied over a very active nickel catalyst supported on mineral palygorskite. The transformation of biodiesel into green diesel was also studied. The physicochemical characteristics of the RFRMs were correlated with their composition and the conditions and procedure of their preparation. The composition of the reaction liquid mixture in total green diesel follows the order: 98% (CHO), 83% (WCO), 68% (FAD) and 10% (SCGO). Biodiesel is transformed much faster into green diesel than RFRMs. The catalyst use does not affect its main physicochemical characteristics. The activity trend was rationalized in terms of the relative surface concentrations of the supported nickel phases and on the basis of some molecules present in the RFRMs which may bring about catalyst deactivation.