Emission Performance of Lignin-Derived Cyclic Oxygenates in a Heavy-Duty Diesel Engine

In earlier research, a new class of bio-fuels, so-called cyclic oxygenates, was reported to have a favorable impact on the soot-NOx trade-off experience in diesel engines. In this paper, the soot-NOx trade-off is compared for two types of cyclic oxygenates. 2-phenyl ethanol has an aromatic and cyclohexane ethanol a saturated or aliphatic ring structure. Accordingly, the research is focused on the effect of aromaticity on the aforementioned emissions trade-off. This research is relevant because, starting from lignin, a biomass component with a complex poly-aromatic structure, the production of 2-phenyl ethanol requires less hydrogen and can therefore be produced at lower cost than is the case for cyclohexane ethanol. The goal of this paper, realized by means of experiments on a modified DAF heavy-duty diesel engine, is to investigate whether or not the (potentially prohibitively) expensive hydrogenation step from 2-phenyl ethanol to cyclohexane ethanol has an added value from an emissions perspective. The results suggest that this is not the case and hydrogenation therefore does not seem like an interesting additional step in the production process.