Second generation biofuels production from waste cooking oil via pyrolysis process

Aïda Ben Hassen Trabelsi, Kaouther Zaafouri, Withek Baghdadi, Slim Naoui, Aymen Ouerghi

Index: 10.1016/j.renene.2018.04.002

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Abstract

The thermal cracking of waste cooking oil (WCO) via pyrolysis was performed using a laboratory scale fixed-bed reactor. The effects of the final pyrolysis temperature (from 550 to 800 °C) and the heating rate (5°C/min, 15°C/min, 20°C/min, 25°C/min) on pyrolysis products distribution has been investigated and a maximum bio-oil yield of 80 wt% has been obtained at 800 °C and 15°C/min. The bio-oil fuel properties shows that this pyrolytic oil has high caloric value (HHV around 8843 Kg/Kcal) promoting its use as a liquid fuel but some other properties (high acidity index around 126.8 mg KOH/ g sample and high viscosity about 8.95 cSt) need to be upgraded. The GC/MS characterization of the bio-oil highlights its high molecular complexity allowing it to be used as source of chemical products and of active molecules. The syngas heating value (reaching 8 MJ/Kg) is suitable for its application as source of energy for the pyrolysis reactor. The remaining biochar is suitable for application as fertilizer since it is rich of iron and organic carbon. The stochiometric model of WCO pyrolysis has been established basing on the pyrolysis products yields, the CHNS-O composition of raw material and remaining biochar, and the syngas chemical composition.