Biodiesel (B100)

This section describes the basic considerations for handling and blending B100. In the United States, it is equally common to handle B99 and B99.9 blends. The considerations in this section also apply to B99 and B99.9, as these fuel blends often qualify for a tax credit for biodiesel blending. At the time of this writing (2016), a tax credit for blending biodiesel is available through 2016. The storage and handling procedures for B100 are very different than for B20 and lower biodiesel blends and vary significantly from those for diesel fuel. Table 2 lists some of the physical and chemical properties of B100 and petroleum diesel. Using B20 and lower blends significantly reduces or eliminates the effects of these property differences for use as an engine fuel. However, because many distributors store and handle B100 before blending, a good understanding of B100 properties is valuable. Several significant attributes specific to B100 that should be considered when handling, storing, and using it are described below.

• B100 is a good solvent. It may loosen or dissolve varnish and sediments in fuel tanks and fueling systems left by conventional diesel over time. If a system contains sediments, the tanks and fuel system should be cleaned before B100 is handled or used. A good indication that B100 is cleaning the tank is an initial increase in filter plugging. Overtime, filter change intervals should return to normal.This should not be an issue for B20 or lower blends.
• B100 gels at higher temperatures than most diesel fuel. This must be taken into account if handling or using B100, especially in above ground storage tanks (ASTs). The temperature where B100 starts to gel will vary with the feed stock and can range from 0°C to 15°C (32°F to 60°F) or higher, so heated fuel lines and tanks may be needed during winter, even in moderate climates. As B100 begins to gel, the viscosity rises to much higher levels than most diesel fuel, which can increase the stress on pumps. The high cloud point of B100 makes its use challenging in colder climates.
• B100 is not compatible with some hoses and gaskets. B100 may soften and degrade certain types of rubber compounds used for hoses and gaskets(buna-N, nitrile, natural rubber) and may cause them to leak and degrade to the point where they crumble and become useless. For bulk handling of B100, seals, gaskets, and hoses must be compatible with B100. (See Appendix C for information about material compatibility.) Using B100 in an engine constructed with incompatible materials can cause a fuel spill on a hot engine, ruin a fuel pump, or clog a filter as the hose material gradually erodes.Use extreme care to ensure that any part of the fuel system that touches the fuel is compatible with B100. Some systems may employ certain grades of Viton, which are biodiesel-resistant materials, but many do not, because these materials are usually slightly more expensive.
• B100 is not compatible with some metals and plastics. Biodiesel will degrade and form high sediment levels if contacted for long periods by copper or copper-containing metals (brass, bronze) or with lead, tin, or zinc (galvanized surfaces). These high sediment levels may clog filters. B100 may also permeate some common plastics (polyethylene,polypropylene) over time, so these should not be used for storing B100.