Chicken fat and biodiesel viscosity modification with additives for the formulation of biolubricants

Abstract

This study aimed to develop a lubricant from chicken fat and biodiesel, using additives to meet the standards of physicochemical and environmental quality of the ISO 15380-2012.The raw material was extracted directly from chicken skin; using two methods: autoclaving and direct heating, being the latter which generated the higher extraction yield (52.06%). Fat purification (physical refining) was performed by degumming, bleaching and fractionation, where in the fat was transformed from a two-phase mixture to a single-phase solution with improved physicochemical characteristics: viscosity, acid value and mainly fatty acids (48.21%) with prevalence of oleic acid. Viscosity modifiers were added in different ratios (EVA and SBS) following a categorical multifactorial experimental design. As a result, fat mixed with EVA 3 and 4% generated products with similar physicochemical properties to a commercial lubricant, i.e. kinematic viscosity at 40°C and 100°C was 108.47 to 174.78 and 20.65 to 27.47mm2/s, respectively.Biodegradability of formulations were estimated with the BOD5/COD to give a value of 0.6 showing that the product is biodegradable. Thermogravimetrical analysis were done and results demonstrate that thermogravimetrical characteristics are improved if are compared with those of mineral lubricants.Results from this work show that chicken fat is a viable alternative to formulate biolubricants with physicochemical and thermic characteristics to those from commercial lubricants with the advantage of coming from a residual feedstock and being biodegradable.