Critical technical areas for future improvement in biodiesel technologies

This article analyses critical technical areas that currently limit the success of biodiesel as a fuel. The production process is currently shifting from homogeneous to heterogeneous using solid catalysts for a cleaner process and ease of product separation. The free fatty acid and moisture contents in the raw materials must be sufficiently low to avoid soap formation. The production of biodiesel with full compliance with ASTM D6751-07 or EN 14214: 2003 is an uphill task. Current technologies for biodiesel production still do not provide more significant energy surplus. Biodiesel has relatively lower energy content, causing higher fuel consumption. Biodiesel has a drawback in terms of its cold flow properties. A high iodine value can cause degradation and polymerization of biodiesel components. Unconverted monoglyceride, diglyceride and triglyceride impurities will affect the engine performance. The alcohol content in biodiesel can attack rubber seals and gaskets. Biodiesel also can undergo chemical and biological modification to affect its quality in long-term storage. Biodiesel is also associated with high-level NOx emission, a fact that needs special attention.