6 - Fuel Properties

Abstract

This chapter focuses on fuel properties of biodiesel. Generally, Cetane Number (CN) is a dimensionless descriptor of the ignition quality of a Diesel Fuel (DF). As such, it is a prime indicator of DF quality. In addition to CN, gross Heat of Combustion (HG) is a property proving the suitability of using fatty compounds as DF. The cetane scale clarifies why triacylglycerols as found in vegetable oils, animal fats, and derivatives, thereof, are suitable as alternative DF. The chapter presents that the performance of biodiesel during cold weather may restrict its commercial viability during cold weather in moderate climates. It examines the effects of cold temperatures on biodiesel in neat form (B100) and in blends with diesel fuel made from petroleum middle distillates (petrodiesel), discusses fuel properties for assessing performance of diesel fuels as well as effects of blending with biodiesel, reviews effects of cold temperatures during storage on fuel quality and performance, summarizes approaches based on available technology for improving the performance of biodiesel, and examines promising research and development efforts to enhance the cold flow properties to improve the performance of biodiesel. The chapter discusses viscosity and oxidative stability of biodiesel, explains two issues: (i) lubricity of neat biodiesel as well as its components and how this plays a role for petrodiesel fuels and (ii) the interaction of biodiesel with lubricants in the crankcase of a diesel engine. It further presents a summary of the University of Idaho research related to biodegradability, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and toxicity of biodiesel.