Zhou, L., Heuser, B., Boot, M., Kremer, F. et al., "Performance and Emissions of Lignin and Cellulose Based Oxygenated Fuels in a Compression-Ignition Engine," SAE Technical Paper 2015-01-0910, 2015, doi:10.4271/2015-01-0910.
Lignocellulosic biomass consists of (hemi-) cellulose and lignin. Accordingly, an integrated biorefinery will seek to valorize both streams into higher value fuels and chemicals. To this end, this study evaluated the overall combustion performance of both cellulose- and lignin derivatives, namely the high cetane number (CN) di-n-butyl ether (DnBE) and low CN anisole, respectively. Said compounds were blended both separately and together with EN590 diesel. Experiments were conducted in a single cylinder compression ignition engine, which has been optimized for improved combustion characteristics with respect to low emission levels and at the same time high fuel efficiency. The selected operating conditions have been adopted from previous “Tailor-Made Fuels from Biomass (TMFB)” work. Although particulate matter emissions benefitted from the combination of anisole and DnBE, overall performance, including also indicated efficiency, load ignitability, as well as unburnt hydrocarbon and carbon monoxide emissions, was best for the diesel blend with the lowest anisole concentration of 10% and a CN of 45. Furthermore, the results suggested that CN has more impact than fuel oxygen content, with lower CN leading to improved overall performance. This improvement, however, appeared to have an optimum for CN's in the range of 37-45. A further reduction to 30.5 or increase to 56 generally decreased overall performance.