Preparation Of Biodiesel Fuel From Waste Cooking Oil By Two-step Method

Facing the dual pressure of resources scarcity and environmental pollution, people areconstantly looking for a recycled and environmentally friendly new energy. As oil reserves fallsharply and the rising prices of fossil fuel, People try to use biodiesel instead of fossil diesel.,Waste cooking oil is always a big problem troubled people in China, Improper use will not onlypollute the environment,but also harm people’s health. So people focus on how to make wastecooking oil into biodiesel.In this paper, waste cooking oil was as material and pretreated before experiment, includingpurification, degumming, color-removing and dehydration. Biodiesel was obtained from wastecooking oil by two-step method. First, activated carbon supporting p-toluene sulfonic acid wasselected as catalyst to catalyze the esterification of free fatty acids and methanol for getting fattyacid methyl ester. And the reaction conditions were optimized by single factor test andorthogonal test, respectively. In the optimal condition, the conversion can reach up to95%, andthe optimal condition were determined, i.e., molar ratio of methanol to oil, dosage of catalyst,reaction temperature, and reaction time were20:1,6wt%,70oC, and3h, respectively. Second,solid base was used as catalyst to catalyze transesterfication, and calcined Ca(CH3COO)2at700oC has the best catalytic effect. The reaction conditions were optimized by single factor testand orthogonal test method, respectively and the optimal condition were that molar ratio ofmethanol to oil, dosage of catalyst, reaction temperature, and reaction time were5:1,1.5wt%,65oC, and2h, respectively.Biodiesel is a kind of clean energy, and mainly refers to fatty acid methyl ester derived fromthe reaction between grease (including animal fats, vegetable oil, waste cooking oil and so on)and alcohol. In this paper, content analysis and performance test of the biodiesel prepared bytwo-step method were done. The results of content analysis show that there are so much fattyacid methyl ester in biodiesel fuel which including25kinds of fatty acid methyl ester above14carbon, the total relative content reaches up to97.75%. In the results of performance test,indexes, including density, viscosity, ignition, flash point, distillation range, cold filter pluggingpoint, and so on, are in the standard range of domestic and foreign biodiesel fuel.