Production and characterization of bio-oil from the pyrolysis of waste frying oil.

In this present work, the disposal of waste frying oil was explored. The experiment tests were performed under nitrogen (N2) atmosphere at 5 °C/min heating rate from the ambient temperature to 500 °C. In these operating conditions, the obtained pyrolitic liquid fraction was 76 wt% formed by 63.87 wt% of crude bio-oil and 12.13 wt% of aqueous fraction. The chemical characterization using FTIR, GC, and GC/MS has revealed that the bio-oil is a complex chemical mixture of linear saturated, unsaturated, and cyclic hydrocarbons and oxygenated compounds such as carboxylic acids, ketones, aldehydes, and alcohols. Moreover, the produced bio-oil can be considered as promising fuel with high calorific value (∼39 MJ/kg). However, the higher acidity (∼125 mg KOH/g sample) and viscosity (9.53 cSt at 40 °C) limit currently its direct use in engines. Therefore, although several promising results, further investigations are requested to improve the bio-oil quality in order to find an environmentally friendly issue to waste frying oil.