An experimental study on fuel filterability and water separation efficiency with biodiesel fuels

With greenhouse gas emissions reduction being the target, many countries are increasing the consumption of renewable energy. Majorly in transportation sector, many countries are moving forward with increase in share of biodiesel fuel usage. But some properties of biodiesel are not compatible with fuel supply components majorly fuel filter, which needs more study for biodiesel to replace fossil fuels significantly in the transportation industry. Two such major concerns affecting fuel filters are the poor water separation efficiency with biodiesel and difficulty in filterability. Biodiesel contains significantly higher water content than diesel fuel. This study was made with biodiesel fuel produced from feedstocks Karanja and waste cooking oil (WCO). This study attempted to make comparison of water separation efficiency of an automotive fuel filter with diesel fuel and biodiesel mixture (50% V/V) of both feedstocks as per JIS D1617. Filterability of biodiesel is relatively difficult because of higher viscosity and presence of oxidation substances in biodiesel. Previous study indicated heating the fuel enabling ease of filterability. This study attempted to further quantify this influence by measuring Filter blocking tendency (FBT) of biodiesel fuels as per ASTM D2068 with fuel preheated to 38°C. Results from the study indicated water separation efficiency of 98.1% and 91.7% with diesel and biodiesel correspondingly. FBT of the Karanja and Waste cooking Oil was found to be 2.24 and 2.52 with fuel preheating, whereas for diesel it is 1. This study concludes that filterability issues with conventional automotive fuel filter can be reduced significantly with fuel preheating, whereas water separation efficiency with biodiesel is poor, as conventional fuel filters are not developed considering the higher water content and hydrophilic nature of biodiesel. Fuel filters with advanced water separation techniques need to be used in place of convention fuel filters.