Comparison and characterization of used and fresh cooking oil and recycling of used oil into biodiesel.

Abstract

Biodiesel from waste frying oil is an effective alternative fuel to conventional diesel and can be directly used as fuel in a diesel engine without any modifications to the engine. The major objective of this work was to compare and characterize used and fresh cooking oil and recycling of used oil into biodiesel using transesterification process. The physicochemical characterization of the biodiesel as well as the effects of process variables on biodiesel yield were evaluated. Also, process conditions for optimum production of biodiesel were determined. The UCO and PCO with methanol and catalyst were heated in a hot plate- magnetic stirrer at a temperature of 60°C and operated at 300 rpm. Sodium hydroxide (NaOH) was used as catalyst. One-Factor-at-A-Time method was used to select the optimum levels of process variable that gives high biodiesel yield. The acid value, free fatty acid, density, moisture content, and saponification value obtained were (0.133 and 0.0605),(0.266% and 0.121%),(0.820g/ml and 0.743g/ml),(0.028 and 0.001) and (187mgKOH/g and 168mgKOH/g) respectively. From the results, the optimum process variables for transesterification process using KOH catalyst were found to be; reaction time of 24hours, methanol to oil molar ratio of 12:1 and catalyst loading of 1.5 wt%. At these optimum conditions, the optimum yield of biodiesel obtained from WCO was found to be 92.5%. Conclusively, WCO has potential to be used for bio-diesel production.