Impact of biodiesel and diesel blends on the fuel filter: A combined experimental and simulation study

Highlights: • CFD and experimental studies were conducted to analyze the effect of biodiesel and diesel blends on the fuel filter. • Filter pressure drop characteristics of biodiesel fuels and diesel are evaluated with experiments and simulation. • Filter blocking tendency and pressure drop increased significantly compared to diesel. • Tensile strength of the filter media reduces with biodiesel fuels. • Fuel preheating, ethanol blending and increased filtration area are recommended. Automotive engines are encouraged to utilize biofuels to lower the net CO₂ and to enhance the usage of renewable energy. With well-proven biodiesel engine characteristics, a comprehensive study about the impact of biodiesel on the fuel filter is lacking in the literature. Hence the current study investigates the comparative impact of higher blends of biodiesel and diesel on the fuel filter. Here, the authors have conducted both experimental and simulation studies on the fuel filter with diesel, two biodiesel fuels namely karanja, and waste cooking oil. Filter blocking tendency (FBT) was measured for the test fuels following ASTM D2068. Also, a comparative tensile strength analysis of an automotive filter media was examined. The test results reveal that FBT increases exponentially with an increase in biodiesel blend concentration with a maximum FBT value of 30 for karanja biodiesel. Further, the tensile strength of the filter media reduces significantly with soaking in biodiesel compared to fossil diesel. Filter pressure drop measurement results with biodiesel were observed to be 35% higher than diesel. Consequently, effective countermeasures such as fuel preheating, varying the filtration area and ethanol blending are proposed to reduce the filter pressure drop with biodiesel. Filter pressure drop with karanja can be reduced similar to diesel fuel by increasing the fuel temperature by 16 °C or enhancing the filtration area by 35%. Karanja blended with 20% ethanol was also observed to have lowered the pressure drop. The present study concludes that neat biodiesel operation affects the filtration process and the filter media of the conventional fuel filter significantly.