Experimental Investigation and Comparison of a Decalin/Butylcyclohexane Based Naphthenic Bio-Blendstock Surrogate Fuel in a Compression Ignition Engine

Abstract

<div class="section abstract"><div class="htmlview paragraph">Many efforts have been made in recent years to find renewable replacements for fossil fuels that can reduce the carbon footprint without compromising combustion performance. Bio-blendstock oil developed from woody biomass using a reliable thermochemical conversion method known as catalytic fast pyrolysis (CFP), along with hydrotreating upgrading has the potential to deliver on this renewable promise. To further our understanding of naphthenic-rich bio-blendstock oils, an improved formulation surrogate fuel (SF), SF1.01, featuring decalin and butylcyclohexane naphthenic content was devised and blended with research-grade No.2 diesel (DF2) at various volume percentages. The blends were experimentally evaluated in a single-cylinder Ricardo Hydra compression ignition engine to quantify engine and emissions performance of SF1.01/DF2 blends. Injection timing events were varied from knock limit to misfire limit at the same operating conditions for all blends. A decrease in the engine power output was observed as the SF content was increased due to lower combustion efficiency, yielding slightly higher <i>CO</i> and <i>THC</i> emissions. Higher SF content also correlated with a significant decrease in the PM emissions. <i>NOx</i> emissions were minimal as they fell below detectable limits. A comparison is also presented between DF2 and previously published SF1/DF2 blends that featured only decalin as the naphthenic content. It was found that butylcyclohexane is more desirable from a combustion performance and emissions characteristic than decalin for the composition of the naphthenic content. A bio-blendstock oil of similar composition to the evaluated SF would be a good candidate for displacing fossil-derived heavy petroleum distillate fuels in engine applications.</div></div>