Recycling of Waste Cooking Oils into a Biodiesel Fuel: Kinetics and Analysis

Abstract

The quantity of waste produced by the food industry is on the rise annually. Among the most prevalent types of waste classified as Class I hazardous substances, posing a significant threat to the environment, is used cooking oils, necessitating proper disposal methods. Concurrently, the combustion of petroleum resources generates substantial greenhouse gas emissions, acting as a primary driver of global warming and associated climatic disruptions. To address the issues mentioned above, food industry waste has been processed into biodiesel fuel. The production involved transformation of sunflower and waste cooking oils with ethanol, with the reaction duration incrementally adjusted between 2 and 7 h in 30 min intervals to determine its effect on biofuel yield. The analysis revealed a pronounced disparity in ester yield between the feedstocks, with the primary component derived from sunflower oil exhibiting a yield 5,81% lower than that obtained from waste oil. For the waste oil substrate, the total ester yield varied from 77.45% (at a 3 h reaction duration) to a maximum of 95.49% (observed at 6.5 h). The temporal evolution of ester release demonstrated a complex, non-monotonic trend, characterized by periodic oscillations superimposed upon a parabolic profile. The confidence interval for the temporal yield data was determined to be ±10%.