effects on engine performance if not removed . The crude biodiesel requires a subsequent refining process in order to meet the strict international biodiesel standard specifications (ASTM D6751 and EN 14214 Standards) .
The process of crude biodiesel refining is complex and it is usually achieved via two techniques; wet and dry washings. Conventionally wet washing is the most widely employed technique to remove these impurities.
The wet washing method employs multiple successive washing steps with water in order to remove major impurities such as soaps, catalyst, glycerol and methanol from biodiesel.