Biodistillate Transportation Fuels 1. Production and Properties

Biodistillate transportation fuels include biodiesel (produced via transesterification of animal fats and vegetable oils) and renewable diesel (produced via catalytic hydroprocessing of the same feedstocks). Production and use of biodistillates are increasing dramatically, both in the U.S. and globally. This paper describes the policy drivers prompting growth of biodistillate fuels in the U.S., Europe, and selected other countries. Trends in fuel production volumes and feedstocks supplies are presented for these fuels. Current feedstocks are dominated by soybean oil in the U.S. and rapeseed oil in Europe. However, there is much interest in developing alternative, non-edible feedstocks such as jatropha and microalgae. Currently, biodiesel is the dominant biodistillate in use, though interest in renewable diesel is increasing. This paper describes different conversion processes used to manufacture these fuels, and discusses the pros and cons of each. Chemical and physical properties of biodistillates are presented, along with a discussion of the relevant fuel specifications established by ASTM and other organizations. Measures to assure satisfactory fuel quality are explained. Finally, in-use handling and performance of biodistillates are discussed, focusing on issues such as fuel stability and low-temperature operability where special precautions may be necessary to ensure satisfactory quality. INTRODUCTION AND BACKGROUND In recent years, production and use of biofuels have increased dramatically, both in the U.S. and around the world. This growth is driven by somewhat different factors from one country to the next, but the strongest factors generally include the following:  National energy security  Diversity of energy sources  Concerns over greenhouse gases (GHGs) and global climate change  Desire for sustainable energy sources  Rural economic development  Improved balance of trade Over the past 10-20 years, most interest and activity regarding biofuels was focused on ethanol, and its use in light-duty gasoline vehicles (LDGV). While ethanol remains a topic of considerable activity and debate, recent years have seen rapid growth in other biofuels meant for blending with diesel fuel and used in vehicles with compression ignition (CI) engines. Numerous aspects of biofuels are of interest and importance – including feedstocks, production technologies, fuel properties and standards, performance and handling, vehicle emissions, and lifecycle impacts. Due to the evolving nature and rapid growth of information in these areas, the Coordinating Research Council (CRC) sponsored a study to assess the state-of-knowledge regarding plant-derived biofuels as blending materials for ultra-low sulfur diesel (ULSD) fuel in transportation applications.