Research Progress on Biodiesel Corrosion Problems of Engine Parts

Biodiesel is one of the alternative fuels for engine and has the advantages of renewable and low emission. The physical and chemical properties of biodiesel are different from those of petroleum diesel due to the different raw materials, which causes enhanced corrosion of automotive engine metal and non-metal materials. In order to keep the sustainable development of biodiesel, combing the domestic and foreign relevant literature, the present paper reviews and summarizes the corrosion problems resulting in the effect of biodiesel on engine materials. Biodiesel is more corrosive than diesel, the corrosion rate increases with the increase of biodiesel blend ratio.Impurities, hygroscopicity, oxidation, high temperature and high sulfur content increase the corrosion trend of biodiesel. Some metal materials of engine parts would suffer the chemical and electrochemical corrosion in biodiesel, usually characterized by pitting corrosion. Non-metallic materials such as plastic, rubber and other polymers generally suffer aging when contacting with the biodiesel, characterized by the variation of hardness, volume and quality. Applying the solid acid catalyst, lowering the sulfur content, increasing the purity, selecting appropriate additives and corrosion resistant materials are effective ways to solve the corrosion problem of biodiesel.