A study on two-step biodiesel production of agricultural by-products, namely palm oil derived using activated bleaching earth )UABE), collected from the Oleen Palm Oil industrial refining plant consisting of 22.4 % of waste oil. This waste oil showed free fatty acid content and a saponification value of 15.5 % and 199.7 mg KOH/g, respectively. The FFA content after esterification should be approximately 1.0%, not only to save glycerol and the catalyst involved in the esterification but also to

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... chieve high biodiesel conversion during the transesterification. An alkaline catalyst was successfully used to produce biodiesel in the second step. A 97.6% conversion to biodiesel based on the European Standard EN 14214:2003 was achieved under the conditions (1.0% NaOH catalyst relative to waste oil, the molar ratio of free fatty acid, and methanol of 1:13.22, 60ºC, 1h). Overall, this novel two-step process achieved highly enhanced biodiesel conversion (74.6% to 100.0%) with a significantly increased molar ratio of free fatty acid and methanol (1:2.71 to 1:15.89) and catalyst requirements (1.0% NaOH).