Water content in biodiesel for diesel fuel blends: measurement using centrifuge and coulometric titration method

Biodiesel nowadays is being used as a blend with diesel fuel to promote the renewable fuels. One of the critical parameters of biodiesel is water content, both free and soluble water is covered. Water presence in biodiesel is limited by the specification to prevent fouling in storage and handling facilities and to avoid trouble in fuel system of engine. Currently in Indonesia, the measurement of water in biodiesel use the centrifuge method that measure both of water and sediment content. Refer to diesel fuel specification, water content is measured separately from sediment content. In order to prepare higher biodiesel percentage in diesel blends (up to 30%) as the Government of Indonesia planning in 2020, water content measurement in biodiesel need more accurate method. In this study, we present the measurement of water content in 20 biodiesel samples using 2 methods: the centrifuge and coulometric titration method. The result show that all biodiesel samples having different water content vary from 173.36 ppm to 968.12 ppm, while all water and sediment content from 20 biodiesel samples are mostly nil, only 1 sample has 0.05 vol % water and sediment.