Study on Biodiesel Production from Waste Cooking Oils Containing Animal Fats

Recently, biodiesel has attracted attention as a possible petroleum substitute. Biodiesel is an alternate diesel fuel formed from triacylglycerols, which are the principal ingredient of oils and fats. However, in Japan, there is not enough land space to cultivate the raw materials for such oils and fats, and most imported oils and fats are used for food purposes, such as cooking oil. Furthermore, most of the waste cooking oils includes animal fats which contain long-chain saturated compounds and free fatty acids. The former has a high freezing point and the latter forms a soap with the alkali catalyst used in biodiesel production, reducing the yield. The biodiesel production from the waste cooking oil was examined. As a result, it was clarified that ion-exchange resin two step method is suitable for waste oil with little animal fats, and the pyrolysis method is suitable for waste oil with much animal fats