Distillation Profile Research Articles

Impact of HEFA Feedstocks on Fuel Composition and Properties in Blends with Jet A

Alternative aviation fuels and their approval process contribute to one of the biggest challenges in deployment of an enhanced volume of aviation fuels. One of the approved fuel blending components is hydroprocessed esters and fatty acids (HEFAs) for mixing with petroleum-derived fuel (Jet A/A-1) up to 50 vol %. As the ASTM fuel specification (D7566) is merely based on the performance expected, the final blend concentration of HEFA in Jet A/A-1 can vary depending on the resultant fuel properties. Currently, there is a lack of information on how these properties are affected by the constituent chemical composition. The aim of this study was to compare three HEFAs sourced from different feedstocks (camelina, tallow, and mixed fat) and their blends with Jet A (10–60 vol %) based on the detailed chemical composition. The chemical composition was obtained using two-dimensional gas chromatography with mass spectrometry and flame ionization detector. The properties of interest were the distillation profile, dens...

A combustion model for multi-component fuels using a physical surrogate group chemistry representation (PSGCR)

A combustion model to simulate the oxidation of multi-component fuels has been developed and applied to model autoignition combustion processes. The model is called the Physical Surrogate Group Chemistry Representation (PSGCR) method, which combines a multi-component fuel model to describe the physical properties of the fuel with reduced reaction mechanisms to represent the chemistry of the fuel components. A group of physical surrogate (PS) components are used to describe the fuel’s physical properties, such as the distillation profile, specific gravity, lower heating value and hydrogen-to-carbon (H/C) ratio. The oxidation processes of the fuel are modeled using skeletal reaction mechanisms for a group of chemical surrogate (CS) components that employ generic reactions as well as detailed reaction kinetics. The generic reactions were built to model unavailable reaction pathways from physical surrogates to the base CS components or their intermediate species. The model includes the 6 major chemical classes of typical hydrocarbon fuels, i.e., n-paraffins, iso-paraffins, olefins, naphthenes, aromatics and oxygenates, and 65 representative hydrocarbon components are included in a data base for the physical surrogate components and 43 chemical surrogate components are considered for the group chemistry representation. Six types of generic reaction sets are proposed to model the oxidation of 15 physical surrogate components that are called extended-CS (chemical surrogate) components. The present generic reactions are modeled such that the major characteristics of the oxidation process of the fuel components are included in a consistent manner.The final version of the PSGCR reaction mechanism consists of 264 species and 1292 reactions. Validation of the reaction mechanisms was performed by comparing predicted ignition delay times with experimental measurements and/or predictions from comprehensive mechanisms available in the literature. The model was also validated against HCCI experimental data of the FACE fuels. Then the model was applied to simulate practical diesel fuel (F76) spray combustion in a constant volume chamber, and the predicted ignition delay times of the surrogate model fuel were compared with measured values. The results show that the present PSGCR method captures the combustion characteristics of complex multi-component fuels, giving reliable performance for combustion predictions, as well as computational efficiency improvements for multi-dimensional CFD simulations through the use of reduced mechanisms.

Impact of Biodiesel Addition on Distillation Characteristics and Cetane Index of Diesel Fuels

AbstractThis paper examines the impact of biodiesel addition on density, viscosity, distillation profile, and cetane index of diesel fuels. Biodiesel has become an important component in the European diesel fuel market. Its addition to diesel alters the distillation profile, which in turn may impact on the cetane index; the latter remains an important parameter for the evaluation of ignition quality of diesel fuels, in combination with the cetane number. In this series of experiments, fifty diesel fuel samples were used (35 automotive diesel samples and 15 heating gasoil samples) as base fuels, to which sunflower oil biodiesel was added at a concentration of 5% volume in the fuel blend. The distillation profile, density, and kinematic viscosity were measured in all base fuels and blends, whereas the cetane indices were calculated from density and distillation measurements. As expected, the results showed increased density and kinematic viscosity due to the biodiesel addition, whereas the front end volatil...

Specific Gravity, RVP, Octane Number, and Saturates, Olefins, and Aromatics Fractional Composition of Gasoline and Petroleum Fractions by Neural Network Algorithms

An accurate method for estimation of the properties of petroleum fractions based on their ASTM D86 distillation profile is developed using a set of conventional feed forward single layer neural networks algorithms. Results on 362 gasoline and petroleum fuels show that the proposed method outperforms other alternatives in terms of accuracy, simplicity, and generality with overall correlation coefficients 0.995 for research octane number, 0.994 for motor octane number, 0.995 for Reid vapor pressure, 0.9996 for specific gravity, and 0.994 for saturates 0.992 for olefins and 0.998 for aromatics fractional compositions. The model is suitable for incorporation into ASTM D86 test apparatus to predict the properties of petroleum fractions in a single test, resulting in savings in terms of space, time, energy, and cost.

Behavioural characteristics of adulterated Premium Motor Spirit (PMS)

Distillation profiles and chemical characteristics of ten suspected adulterated Premium Motor Spirit samples randomly collected from different dispensing points were analysed to determine the chemical characteristics of these samples when compared to a reference sample that is not adulterated. Results of the analyses show, Research Octane Number values ranged from 60.10 to 93.30, specific gravity ranged from 0.75 to 0.79, Reid Vapour Pressure ranged from 0.28kgf/cm2 to 0.60kgf/cm2 while Atmospheric distillation ranged from 189 to 251°C. The results of this research reveal that most of the products are highly adulterated and may pose problems when sent to the market for intended end users.

The characterisation of diesel nozzle flow using high speed imaging of elastic light scattering

Two identical, conventional six-hole, valve-covered orifice (VCO) diesel injectors have been modified in order to provide optical access to the region below the needle, and the nozzle-flow passages. This has been achieved through the removal of the metal tips, and their replacement with transparent acrylic tips of identical geometry.These two identical injectors were employed in order to offer comparability between the measurements. One of them had a dark, anodised inner surface at the base, while the other had a silvered inner surface at the base. Elastic scattering of incident white light from the internal cavitating flow inside the nozzle holes of the optically accessible diesel injector tips was captured on a high-speed electronic camera. The optical image data was obtained for three injector rail pressures ranging from 200bar to 400bar, and for five diesel fuels of varying density, viscosity, and distillation profile, in order to identify variations in cavitation flow behaviour inside the nozzle hole passages.A set of mean time-resolved diesel fuel flow images were obtained from 30 successive fuel injection pulses, for each operating condition, for each injector. The mean cavitation image occurring in the nozzle holes was converted to the mean proportion of nozzle hole area producing cavitation-induced optical scattering. The mean normalised area images were then analysed, and were able to demonstrate the anticipated inverse relationship between injected fuel mass and cavitation volume fraction (indicated by mean normalised area), and the effect of fuel viscosity and distillation profile on cavitation volume fraction (again indicated by mean normalised area).

Thermophysical properties needed for the development of the supercritical diesel combustion technology: Evaluation of diesel fuel surrogate models

Development of supercritical fuel combustion technology requires reliable data on fuel properties. In this paper, twenty diesel fuel surrogates (DFSs) have been evaluated for representing real diesel fuel (DF) properties including critical point, density, heat capacity, viscosity and thermal conductivity. The critical temperatures of DF were estimated to be 717–745K largely depending on DF distillation profiles, while those of DFSs varied significantly from 540 to 734K and only those of DFSs #5(n-hexadecane), #17 and #19 were within the range for DF. The best predictions of density, heat capacity, viscosity and thermal conductivity of DF were achieved by DFSs #8 (AAD=0.3%), #4 (1.5%), #20 (13%) and #14 (1.7%), respectively, and DFS #4 (n-tetradecane) had the best overall performance with an AAD of 8%. Finally, a simple methodology has been demonstrated for the evaluation of DFSs, and the current results lead to the best predictions of DF thermophysical properties.

Characterization by chemical and sensory analysis of commercial grape marc distillate (Orujo) aged in oak wood

The main physicochemical parameters and sensory profile of commercial aged distillates from grape marc, Orujo, have been determined in this study. Significant differences were obtained for the mean concentration of the chemical parameters determined among the samples analysed. All samples fulfilled the values fixed for each parameter by the corresponding Regulation Council and the values obtained showed differences with respect those obtained for other similar beverages (whisky, rum, cognac) owing to the characteristics of the raw material employed. The results from sensory analysis showed that Orujo aged over 60 months in wooden barrels from Quercus robur reached the highest overall quality, next to the distillate aged over 144 months in Quercus petraea oak wood. The tasters evaluated more positively the species of oak used in the aging process than the time that the distillate remained in contact with the barrel. Samples aged in oak wood from Quercus robur during 60 months and from Quercus petraea during 144 months had a similar sensory profile and obtained a greater intensity in all qualifying parameters. The principal components analysis clearly showed a good separation of the aged Orujo samples in terms of sensory descriptors according to the species and origin of the oak wood employed in the aging process. Copyright © 2012 The Institute of Brewing & Distilling

Combustion simulations of the fuels for advanced combustion engines in a homogeneous charge compression ignition engine

Numerical simulations of combustion have been performed for a homogeneous charge compression ignition engine operating on multi-component reference diesel fuels. Two surrogate representation methods were used to describe the nine fuels for advanced combustion engines. The first method of surrogates, denoted as physical-surrogate components, was formulated to describe the fuel’s physical properties by matching its distillation profile, specific gravity, lower heating value, hydrogen-to-carbon ratio, and cetane index with measured data. The second method of surrogates, denoted as chemical-surrogate components, was introduced to represent the chemistry of the fuel components using a new group chemistry representation model. In the model, the fuel components in the physical-surrogate components and chemical-surrogate components are related through the classification of chemical structures of the components, i.e. the component in the physical-surrogate components are grouped based on their chemical classes and the chemistry of each group is calculated using a chemical kinetics mechanism (MultiChem) that represents the combustion characteristics of its chemical class. This MultiChem mechanism includes reduced reaction mechanisms for the four main surrogate hydrocarbon chemistry components of diesel fuel, n-paraffins, iso-paraffins, naphthenes, and aromatics, with two n-paraffins to provide the ability to mimic molecular weight effects. The computations were performed using a multi-dimensional computational fluid dynamic code, KIVA-ERC-CHEMKIN, and the results show that the predictions of the present multi-component combustion models are in good agreement with experimental measurements. The combustion characteristics of the fuels for advanced combustion engines are well represented and the present models are well suited for practical engine computations.

Distillation profiles in ternary heterogeneous mixtures with distillation boundaries: staged columns

Distillation profiles in ternary heterogeneous mixtures with distillation boundaries: staged columns Distillation boundaries originate from saddle azeotropes, dividing the composition space into distillation regions. In heterogeneous mixtures distilled in packed columns, distillation regions overlap. The common area of distillation regions is parametrically sensitive, and it determines the possibilities of crossing (at a finite reflux) the distillation boundaries defined for a total reflux or reboil ratio. This work is an extended research of the paper (Królikowski et al., 2011) conducted to scrutinize whether the distillation regions overlapped in heteroazeotropic systems distilled in staged columns. Presented studies were performed by finding such composition points of the products, for which the rectifying profiles of staged columns were ended in different distillation regions. Calculations were executed for the heterogeneous mixture classified under Serafimov's topological class as 3.1-2: ethanol - benzene - water. Distillation regions for staged columns were found to overlap each other in the heterogeneous systems. As a result, their common part was parametrically sensitive.

Cachaça distillation investigated on the basis of model systems

This work reports experimental tests using commercial spirits that were diluted and had their initial composition modified in order to better measure the distillation behavior of selected minor compounds of importance for the quality of alcoholic beverages. Such compounds were added to the commercial cachaça and the corresponding model wine, obtained after the spirits' dilution, was distilled. In this way a more precise distillation profile could be determined for those minor compounds. The alembic heating was performed by electrical resistance and the corresponding heat transfer coefficient was determined by analyzing the thermal behavior of the still during the distillations. A simulation algorithm was developed, including the mass and enthalpy balances as well as the heat transfer flux to the boiling wine. Good agreement between experimental and simulated results was obtained for the distillate rate, alcoholic graduation, temperature and most minor component profiles.

Use of Surrogate Bends to Explore Performance-Composition Links for Synthetic Paraffinic Kerosines

Abstract Fischer-Tropsch synthetic paraffinic kerosines (FT-SPKs), such as Gas-to- Liquids (GTL) Kerosine, are now accepted as suitable blend components for Jet fuel production, via ASTM D7566. This sets limitations on distillation profiles for the final fuel and neat SPK, and the cycloparaffin content of the neat SPK. SPKs, from FT and other production routes, can be envisaged that would fall outside these limits yet produce perfectly acceptable, even desirable fuels. They are not generally available yet but one can define their compositions in terms of key components (normal paraffins, iso-paraffins and cycloparaffins) and carbon number distributions, derived from 2-dimensional gas chromatography. Surrogate blends approximating to these compositions have been produced with existing FT kerosines and commercial solvents. The methodology used to blend these surrogate fuels will be presented as well as the results of the first experimental campaign at Rolls-Royce Derby on 5 real and surrogate SPKs in Technology Readiness Level 3 (TRL 3) altitude relight tests, with a baseline crude-derived Jet A-1. SPK choices permitted the impact of several main compositional variables on laboratory and performance measures to be determined from the small fuel set. Standard specification tests and altitude relight tests were performed. Not only were engine/combustor performances assessed but also combustion processes were captured with high speed flame imaging subject to a poster by DLR (Mosbach et al). Laboratory tests showed some sensitivity to SPK composition (e.g. viscosity increasing and lower heating value decreasing with increased cycloparaffin content) but these were less evident with ignition relight test results. All SPKs ignited, suggesting that the distillation criteria could be relaxed from current values. There may be a positive impact of lower iso/normal content on ignition performance, but this needs testing in more advanced (higher TRL) equipment.

Surrogate Model Development for Fuels for Advanced Combustion Engines

The fuels used in internal-combustion engines are complex mixtures of a multitude of different types of hydrocarbon species. Attempting numerical simulations of combustion of real fuels with all of the hydrocarbon species included is highly unrealistic. Thus, a surrogate model approach is generally adopted, which involves choosing a few representative hydrocarbon species whose overall behavior mimics the characteristics of the target fuel. The present study proposes surrogate models for the nine fuels for advanced combustion engines (FACE) that have been developed for studying low-emission, high-efficiency advanced diesel engine concepts. The surrogate compositions for the fuels are arrived at by simulating their distillation profiles to within a maximum absolute error of ∼4% using a discrete multi-component (DMC) fuel model that has been incorporated in the multi-dimensional computational fluid dynamics (CFD) code, KIVA-ERC-CHEMKIN. The simulated surrogate compositions cover the range and measured concen...

Distillation profiles in ternary heterogeneous mixtures with distillation boundaries

Distillation boundaries are created by saddle azeotropes and divide the composition space into distillation regions. In this study, the behavior of rectification profiles was investigated in the following heterogeneous systems: benzene, tert-butanol, water and ethanol, water, toluene. These systems were chose in order to scrutinize whether distillation regions overlapped. The experiments were performed using Distil (afterwards Conceptual Engineering) software from AspenTech, Inc. For each type of distillation column (staged and packed), a different pair of distillation boundaries is referred (TRB & PDB and SDB & PDB accordingly). Similar to homogeneous mixtures, distillation regions were found to overlap each other in heterogeneous mixtures. As a consequence, their common part was parametrically sensitive.

Phenolic Compounds and Furanic Derivatives in the Characterization and Quality Control ofBrandy de Jerez

This article shows the results obtained in the study of the extraction profiles from oak wood to distillate of several compounds, low molecular weight phenolics, and furanic derivatives, and the relationship of their contents with those found in commercial sherry brandies and other aged distillates of different geographical origin, in order to research the utility of these analytical variables for explaining the highly specific character of Brandy de Jerez. Using multivariate statistic techniques, the aging system (static by anadas, or dynamic, well known as Soleras y Criaderas) has been confirmed as having a great influence on the analytical profile of aged distillates (discrimination is up to 100%). Differences between commercial brandies and those aged experimentally of equivalent average age have also been confirmed. The Solera Gran Reserva Brandies de Jerez show a clear differentiation from the rest of the distillates of different origin (discrimination is up to 80%), indicating their highly specific character.

Bio-calorimeter: smart system to control fermenter for protease production from Aspergillus tamarii

Zymomonas mobilis and Saccharomyces cerevisiae have been used for simultaneous saccharification and fermentation of sorghum grain with the reuse of the stillage. This study investigated the effects of replacing half the water by a stillage liquid fraction on ethanol yield and volatile compound synthesis. Studies have shown that Z. mobilis is more efficient in ethanol production (55.96–61.48 g/L) than S. cerevisiae (55.26–58.38 g/L). Additionally, Z. mobilis had the advantage of a shorter fermentation time (48 h) and lower fermentation temperature (35 °C) than distillery yeast. No relationship was observed between successive stillage reusing and ethanol content. Reusing the liquid fraction of the stillage did not increase the amount of volatile compounds identified in the raw distillates. Significant differences were observed in the volatile compounds profile of bacterial and yeast raw distillates. Acetaldehyde was the dominant compound in bacterial raw distillates, whereas 3-methylbutan-1-ol was the dominant compound in yeast raw distillates. The characteristic of Z. mobilis was the production of fewer (4.31–6.03 g/L spirit 100%) volatile compounds compared to yeast (4.04–7.44 g/L spirit 100%). The fermentation process reusing the liquid part of the stillage made it possible to reduce process water consumption and waste generation in bioethanol production from sorghum grain. In addition, Z. mobilis made ethanol production from sorghum grain grown in Eastern Europe more beneficial.

Incorporating Tangent Pinch Points into the Conceptual Modeling of Batch Distillations: Ternary Mixtures

This contribution explores the influence of tangent pinch points on the performance of batch distillations of highly nonideal ternary mixtures and its incorporation into a conceptual modeling framework under the assumption of a rectifier with an infinite number of stages. The maximum feasible distillate composition on the line of preferred separation and its corresponding limiting reflux ratio are first determined with the aid of bifurcation analysis of reversible distillation profiles. Then, the dependence of feasible distillate mole fractions on reflux ratios above the limiting one is calculated by solving a nonlinear equation system, which incorporates the tangency condition. Results obtained from the conceptual model for instantaneous column performance are in excellent agreement with those calculated from rigorous simulation. Two highly nonideal ternary mixtures are studied.

Petroleomics: Chemistry of the underworld

Each different molecular elemental composition-e.g., C(c)H(h)N(n)O(o)S(s)-has a different exact mass. With sufficiently high mass resolving power (m/Deltam(50%) approximately 400,000, in which m is molecular mass and Deltam(50%) is the mass spectral peak width at half-maximum peak height) and mass accuracy (<300 ppb) up to approximately 800 Da, now routinely available from high-field (>/=9.4 T) Fourier transform ion cyclotron resonance mass spectrometry, it is possible to resolve and identify uniquely and simultaneously each of the thousands of elemental compositions from the most complex natural organic mixtures, including petroleum crude oil. It is thus possible to separate and sort petroleum components according to their heteroatom class (N(n)O(o)S(s)), double bond equivalents (DBE = number of rings plus double bonds involving carbon, because each ring or double bond results in a loss of two hydrogen atoms), and carbon number. "Petroleomics" is the characterization of petroleum at the molecular level. From sufficiently complete characterization of the organic composition of petroleum and its products, it should be possible to correlate (and ultimately predict) their properties and behavior. Examples include molecular mass distribution, distillation profile, characterization of specific fractions without prior extraction or wet chemical separation from the original bulk material, biodegradation, maturity, water solubility (and oil:water emulsion behavior), deposits in oil wells and refineries, efficiency and specificity of catalytic hydroprocessing, "heavy ends" (asphaltenes) analysis, corrosion, etc.

Prediction of the distillation profile and cold properties of diesel fuels using mid-IR spectroscopy and neural networks

In this paper, the distillation curve points and certain cold properties of diesel fuel fractions were determined by means of mid infrared spectroscopy (IR) and artificial neural networks (ANNs). Distinct ANN models were developed for the prediction of the distillation curve with 5% recovery increment, and for the pour (PP) and cloud (CP) points. The properties of interest were measured experimentally following standard ASTM methods. The developed prediction algorithms were tested on unseen data and exhibited high level of accuracy, comparable to the one of the standard laboratory methods. The presented algorithms can be used as a rapid and reliable tool in quality control applications of the various fractions involved in diesel fuel production, since they can determine several important properties simultaneously based on a single and fast IR measurement.

Solvent blends based on dipropylene glycol dimethyl ether for the production of alkyd and polyester resins by the azeotropic process

Solvent blends based on dipropylene glycol dimethyl ether (DPGDME) and non-HAP hydrocarbons were evaluated as xylene replacements for the preparation of alkyd and polyester resins by the solvent reflux process. Screening criteria included water partitioning properties, autoignition temperature, distillation profile, and water removal efficiency. A series of resins was also prepared by an identical procedure in order to compare the performance of the DPGDME solvent blends with that of the xylene control. Several of the DPGDME/hydrocarbon blends exhibited desirable partitioning properties and autoignition temperatures >350°C. These blends were close-boiling and when distilled in the presence of water, formed minimum boiling pseudo-heterogeneous azeotropes containing about 50% water. Size exclusion chromatography data showed that resins made with the DPGDME blends had essentially the same molecular weight distribution profile as those made with xylene.