Global extinction strain rate experiments of single large hydrocarbon fuels

Includes bibliographical references.An experimental validation study of the flame extinction characteristics of large hydrocarbon fuels is carried out. A counterflow flame burner combined with a liquid fuel vaporization system is utilized at a reduced pressure of 0.84 atm to measure the diffusion flame global extinction strain rate of liquid fuels as a function of fuel dilution. A numerical study is also employed using CHEMKIN to calculate the global extinction strain rate of hydrocarbon fuels, including n-heptane, n-decane, and toluene. Flame extinction measurements of the blended fuels are compared to global flame extinction predictions using a previously published radical index methodology

Physiochemical Property Characterization of Hydrous and Anhydrous Ethanol Blended Gasoline

Water removal during the production of bioethanol is highly energy intensive. At the azeotropic point, the mixture can no longer be separated via fractional distillation, so expensive and energy intensive methods are required for further purification. Hence, there is an interest in using hydrous ethanol at the azeotropic point to improve the energy balance of ethanol fuel production. Currently there is a lack of available thermophysical property data for hydrous ethanol gasoline fuel blends. These data are important to understand the effect of water on critical fuel properties and to evaluate the potential of using hydrous ethanol fuels in conventional and optimized spark ignition engines. In this study, gasoline was blended with 10, 15, and 30 vol % of anhydrous and hydrous ethanol. The distillation curve, Reid vapor pressure, vapor lock protection potential, viscosity, density, haze and phase separation points, and lower heating value were measured for each blend, and the results were compared to ASTM D4814, the standard specification for automotive spark ignition engine fuels. The majority of the properties measured for the low- and midlevel hydrous ethanol blends are not significantly different from those of the corresponding anhydrous ethanol blends. The only differences observed between the hydrous and anhydrous fuels were in their viscosity and phase separation. The viscosity increased as the total water content increased, whereas the phase separation temperatures decreased with an increasing hydrous ethanol fraction. The results of this study suggest that hydrous ethanol blends may have the potential to be used in current internal combustion engines as a drop-in fuel and in future engine designs tuned to operate on fuels with high levels of ethanol

Poly(oxymethylene) Ethers: Alternative Diesel Fuels with Low Sooting Tendencies

Presentation given at the 2022 ACS Fall Meeting in Chicago IL on August 25 2022. Soot has been identified as the second-largest source of climate change after CO2 and it contributes to ambient fine particulates that cause millions of deaths worldwide each year. Diesel engines contribute significantly to total soot emissions because diesel fuels have high sooting tendencies. Poly(oxymethylene) ethers (POMEs) are alternative diesel fuels that can be produced from waste CO2 with low soot emissions. The structures of the POMEs in these earlier studies are alternating oxygen and carbon atoms terminated with methyl groups on both ends. Unfortunately, these methyl-POMEs suffer from high water solubility and low energy density. Replacing the methyl groups with larger alkyl groups can overcome these disadvantages, but at the cost of higher sooting tendencies. To optimize this trade-off, the sooting tendencies of methyl-POMEs and alkyl-POMEs need to be quantified. In this work, a series of methyl-POMEs and alkyl-POMEs were synthesized and their sooting tendencies were quantified. The test compounds contained a wide range of terminating groups (methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl, iso-pentyl, and tetrahydrofurfuryl), cases where the terminating groups were identical at the two ends and where they differed, and from one to five oxymethylene units. The sooting tendencies were characterized by the Yield Sooting Index (YSI), which is based on the maximum soot concentration measured in coflow diffusion flames whose fuel is CH4 doped with 1000 ppm or 3000 ppm of each test compound. The YSIs of the POMEs vary significantly with fuel structure, but in all cases are at least one order of magnitude lower than a certification diesel fuel. We proposed some decomposition pathways that justified the difference among the YSIs. The lower heating value (LHV) was also measured to evaluate the energy penalty of the oxygen atoms. The calculated YSI/LHV of the POMEs are lower than conventional diesel fuels and their components. </p