Evaluation of Anti-Knock Quality of Dicyclopentadiene-Gasoline Blends

Abstract

Increasing the anti-knock quality of gasoline fuels can enable higher efficiency in spark ignition engines. In this study, the blending anti-knock quality of dicyclopentadiene (DCPD), a by-product of ethylene production from naphtha cracking, with various gasoline fuels is explored. The blends were tested in an ignition quality tester (IQT) and a modified cooperative fuel research (CFR) engine operating under homogenous charge compression ignition (HCCI) and knock limited spark advance (KLSA) conditions. Due to current fuel regulations, ethanol is widely used as a gasoline blending component in many markets. In addition, ethanol is widely used as a fuel and literature verifying its performance. Moreover, because ethanol exhibits synergistic effects, the test results of DCPDgasoline blends were compared to those of ethanol-gasoline blends. The experiments conducted in this work enabled the screening of DCPD auto-ignition characteristics across a range of combustion modes. The synergistic blending nature of DCPD was apparent and appeared to be greater than that of ethanol. The data presented suggests that DCPD has the potential to be a high octane blending component in gasoline; one which can substitute alkylates, isomerates, reformates, and oxygenates. IntroductionCarbon mitigation has motivated the development of downsized spark-ignited light duty engines while simultaneously turbocharging them. The energy requirement from light duty vehicle fleets is expected to decrease by almost 10% from 2014 to 2040 [1], due to engine efficiency gains and increased hybridization. The efficiency of spark ignited engines is connected to the fuel octane index (OI = RON -K*S), where RON is the research octane number, S is the octane sensitivity, and K is an empirical constant that depends on engine operating conditions [2]. Increasing the OI of a fuel would maximize tank-to-wheel carbon reductions [3]. However, refinery processes associated with increasing the fuel's anti-knock quality may have an adverse effect on well-to-tank efficiency and cost, depending on the composition of the blend stocks [4]. The use of renewable cellulosic-derived high octane gasoline blending components, such as ethanol, butanol, furans, or lignin-derived aromatics [5,6,7] are a potential solution to achieving high well-to-wheel efficiency, but significant technical, economical, and environmental challenges are slowing their progress to market.Another possible solution is to optimize the use of petroleum refinery-derived components to increase the anti-knock quality of gasoline. The present gasoline refining process consists of multiple processes -including cracking, alkylation, isomerization, and reformation -to modify the chemical composition of the light and heavy naphtha streams obtained from fractional distillation. The alkylation unit converts low value light compounds, such as isobutane, to higher octane gasoline compounds, mainly C7 and C8 compounds, such as 2,4-dimethylpentane and isooctane. In this unit, sulfuric or hydrofluoric acid...