Biodiesel from Direct Transesterification of High FFA Oils through Binary Feedstock Blending: Synthesis and Testing

Inadequate feedstock availability and difficulty associated with the direct transesterification of high FFA oil are the two major challenges to be encountered in the smooth switching from diesel to biodiesel. This can be effectively tackled by deriving biodiesel from blended feedstocks as blending of suitable feedstocks not only limits the FFA of the feedstock, but also provides steady and sustainable feedstock to meet the biodiesel demand. Present work deals with the preparation and characterization of biodiesel derived from binary blends of waste cooking oil with pongamia and mahua oil. The biodiesel with lowest viscosity is selected and subjected to testing in a single cylinder combustion ignition engine to identify the performance and emission characteristics. The binary blends in the ratio 80:20 and 70:30 respectively for waste cooking oil-pongamia oil and waste cooking oil-mahua oil combinations is found to be suitable for direct transesterification with a limiting FFA of 2%. The biodiesel obtained through direct transesterification of waste cooking oil- pongamia oil binary blend with the lower viscosity of 4.13 cSt is found to have better performance and emission characteristics, compared to biodiesel derived from the parent feedstocks.