Effect of renewable diesel and jet blending components on combustion and emissions performance of a HCCI engine

Renewable diesel and jet blending components may be produced by hydrotreating waste fats and vegetable oils. The resulting hydrocarbon components are paraffinic in nature and free of sulfur and aromatics. An isomerization process may follow to improve the cold weather properties. The main differences between renewable diesel and jet blending components is that the jet blending components are more volatile, have a lower cetane number and a much lower cloud point. In this study, different percentages of hydrotreated renewable diesel and jet components were blended into an ultra-low sulfur diesel (ULSD) fuel and their effect on homogeneous charge compression ignition (HCCI) combustion and emissions performance was investigated. The experiments were conducted using a Co-operative Fuel Research (CFR) engine coupled to an eddy-current dynamometer. The percentage of renewable blending components was varied from 0 to 100%. HCCI combustion and emissions data was collected at a single relative air/fuel ratio (\u3bb) = 1.2 and engine speeds of 900 and 1200 rpm for each fuel blend. The experimental results indicate that the renewable diesel and jet blending components increased the heat release during low temperature stage and reduced the auto-ignition temperature compared to the ULSD fuel, which tended to advance the combustion phasing at a fixed compression ratio. The thermal efficiency was not significantly affected by renewable jet and diesel blends up to 10% by volume, but the renewable jet improved the thermal efficiency while the renewable diesel blends deteriorated thermal efficiency for higher percentage blends. The renewable jet fuel component improved unburned hydrocarbon (HC) emissions, but the renewable diesel component did not have a significant effect on HC emissions. Both renewable fuel components reduced CO emissions at a fixed compression ratio, but there was not a clear trend for CO emissions at the optimal thermal efficiency condition when renewable components were blended with the ULSD fuel. The NOx emissions were extremely low and did not show a clear trend as the percentage of renewable blending components increased.NRC publication: Ye

Chemical compositions and properties of lignin-based jet fuel range hydrocarbons

Sustainable aviation fuels remain the only near, mid, and likely long term solution for lowering the carbon emissions of commercial and military aviation. Determination of sustainable aviation fuel’s chemical compositions and prediction of their properties is a critical first step for further research and development leading to the final certification process. Our analytical results showed that the lignin-based jet fuel (US patent 9,518,076 B2) consists of mainly paraffinic hydrocarbon species. They can be further classified into several classes, including n-paraffins, iso-paraffins, mono-, di-, and tri-cycloparaffins of which the majority contains carbon numbers in the range of 7–20. The very high concentration of polycycloparaffins along with the relatively low content of monocycloparaffins contribute to the high boiling point of the sample. Reducing the boiling point will require cracking and further hydrotreating of the lignin-based jet fuel range hydrocarbons to increase monocycloparaffins ratio close to the coal-based jet fuel compositions (e.g., JP-900). Also, this lignin-based jet fuel contains very low aromatics concentration which illuminates favorable energy content, energy density, possible low emissions, and very high-performance characteristics might meet drop-in specifications

Correlations among thermophysical properties, ignition quality, volatility, chemical composition, and kinematic viscosity of petroleum distillates

Thermophysical measurements and Raman spectroscopy were utilized to investigate 17 hydrocarbon distillates derived from Canadian oil sands in this work. Thermal lens and optical interferometer techniques were used to determine the thermal diffusivity (D) and temperature coefficient of the refractive index (dn/dT), respectively. It was found that D and dn/dT are closely correlated with the cetane numbers, distillation temperatures, monocyclic aromatics contents, and kinematic viscosities of the fuels. Raman spectra yielded information on the chemical compositions of the distillates, with aromatic contents proving to be particularly relevant. Multivariate analysis elucidated the relationships among the samples, their properties according to ASTM analyses, and the influence of composition on D and dn/dT.Peer reviewed: YesNRC publication: Ye

Vibrational Spectroscopy and Thermophysical Properties of Ultralow Sulfur DieselAlternative Fuel Binary Blends

Four alternative fuels (AF) were blended with ultralow sulfur diesel (ULSD) at five different proportions (10, 20, 30, 50, and 100 vol % AF) to create 20 binary mixtures in this work. Two renewable jet AFs and two renewable diesel AFs were investigated. Interactions between the components in the mixtures were analyzed by means of spectroscopy (Raman, near-infrared), thermophysical (thermal diffusivity, thermo-optic coefficient), and physical (density) techniques. Correlations among the data were investigated using principal component analysis and partial least-squares regression. Trends in Raman intensities and band positions as well as thermophysical properties showed that the AF/ULSD blends resembled two-component mixtures despite the known complexities of the constituents. Specifically, spectra combined according to the percentages of the components in each mixture; thermophysical and physical properties exhibited similar behavior. The spectra showed strong correlations with all three physical properties, creating the possibility for predicting the properties of similar AF/ULSD mixtures. These properties are governed by the chemical compositions of the fuels

Correction to Diesel Surrogate Fuels for Engine Testing and Chemical-Kinetic Modeling: Compositions and Properties

Correction to Diesel Surrogate Fuels for Engine Testing and Chemical-Kinetic Modeling: Compositions and Propertie