Screening of Potential Biomass-Derived Streams as Fuel Blendstocks for Mixing Controlled Compression Ignition Combustion: SAE Technical Paper No. 2019-01-0570

Mixing controlled compression ignition, i.e., diesel engines are efficient and are likely to continue to be the primary means for movement of goods for many years. Low-net-carbon biofuels have the potential to significantly reduce the carbon footprint of diesel combustion and could have advantageous properties for combustion, such as high cetane number and reduced engine-out particle and NOx emissions. We developed a list of over 400 potential biomass-derived diesel blendstocks and populated a database with the properties and characteristics of these materials. Fuel properties were determined by measurement, model prediction, or literature review. Screening criteria were developed to determine if a blendstock met the basic requirements for handling in the diesel distribution system and use as a blend with conventional diesel. Criteria included cetane number =40, flashpoint =52 degrees C, and boiling point or T90 =338 degrees C. Blendstocks needed to be soluble in diesel fuel, have a toxicity no worse than conventional diesel, not be corrosive, and be compatible with fuel system elastomers. Additionally, cloud point or freezing point below 0 degrees C was required. Screening based on blendstock properties produced a list of 12 that were available as fuels or reagent chemicals or could be synthesized by biofuels production researchers. This group included alkanes, alcohols, esters, and ethers. These candidates were further examined for their impact fuel properties upon blending with a conventional diesel fuel. Blend properties included cetane number, lubricity, conductivity, oxidation stability, and viscosity. Results indicate that all 12 candidates can meet the basic requirements for diesel fuel blending, although in some cases would require additive treatment to meet requirements for lubricity, conductivity, and oxidation stability.