With waste edible oil as raw material to produce biodiesel,free fatty acid has to be removed before used,it will be impractical because the process is complex and the cost is high.

• 废弃油脂含有较多的游离脂肪酸,使用传统方法制备生物柴油时,必须先除去其所含的游离脂肪酸,这将会使过程复杂且增加成本。