Simulated Distillation Data Research Articles

Predicting Petroleum SARA Composition from Density, Sulfur Content, Flash Point, and Simulated Distillation Data Using Regression and Artificial Neural Network Techniques

The saturate, aromatic, resin, and asphaltene content in petroleum (SARA composition) provides valuable information about the chemical nature of oils, oil compatibility, colloidal stability, fouling potential, and other important aspects in petroleum chemistry and processing. For that reason, SARA composition data are important for petroleum engineering research and practice. Unfortunately, the results of SARA composition measurements reported by diverse laboratories are frequently very dissimilar and the development of a method to assign SARA composition from oil bulk properties is a question that deserves attention. Petroleum fluids with great variability of SARA composition were employed in this study to model their SARA fraction contents from their density, flash point, sulfur content, and simulated distillation characteristics. Three data mining techniques: intercriteria analysis, regression, and artificial neural networks (ANNs) were applied. It was found that the ANN models predicted with higher accuracy the contents of resins and asphaltenes, whereas the non-linear regression model predicted most accurately the saturate fraction content but with an accuracy that was lower than that reported in the literature regarding uncertainty of measurement. The aromatic content was poorly predicted by all investigated techniques, although the prediction of aromatic content was within the uncertainty of measurement. The performed study suggests that as well as the investigated properties, additional characteristics need to be explored to account for complex petroleum chemistry in order to improve the accuracy of SARA composition prognosis.

Use of Dual Detection in the Gas Chromatographic Analysis of Oleaginous Biomass Feeds and Biofuel Products To Enable Accurate Simulated Distillation and Lipid Profiling

This contribution describes the development of a chromatographic method capable of simultaneously identifying and quantifying the constituents found in oleaginous biomass—including algae oil—and in biofuel samples through a single cost-effective analysis. Major constituents of the aforementioned analytes include oxygen- and/or nitrogen-containing compounds along with fuel-like hydrocarbons. A novel simulated distillation gas chromatographic (SimDist) technique including dual detection capabilities—specifically flame ionization (FID) and mass spectrometry (MS)—produced identical chromatograms with perfectly aligned signals. FID chromatograms afforded excellent quantitative data while the corresponding MS spectra enabled accurate and thorough compound identification. Simulated distillation data displayed a remarkably linear relationship between retention time and the boiling point of heteroatom-containing compounds in addition to n-alkanes. Indeed, although standard SimDist data were calibrated using the bo...

Evaluation of co-volume mixing rules for bitumen liquid density and bubble pressure estimation

The Peng–Robinson cubic equation of state (CEOS) is widely used to predict thermodynamic properties of pure fluids and mixtures. The usual implementation of this CEOS requires critical properties of each pure component and combining rules for mixtures. Determining critical properties for components of heavy asymmetric mixtures such as bitumen is a challenge due to thermolysis at elevated temperatures. Group contribution (GC) methods were applied for the determination of critical properties of molecular representations developed by Sheremata for Athabasca vacuum tower bottoms (VTB). In contrast to other GC methods evaluated, the Marrero–Gani GC method yielded estimated critical properties with realistic, non-negative values, followed more consistent trends with molar mass and yielded normal boiling points consistent with high temperature simulated distillation data. Application of classical mixing rules to a heavy asymmetric mixture such as bitumen yields saturated liquid density and bubble pressure estimates in qualitative agreement with experimental data. However the errors are too large for engineering calculations. In this work, new composite mixing rules for computing co-volumes of asymmetric mixtures are developed and evaluated. For example, composite mixing rules give improved bubble point predictions for the binary mixture ethane + n-tetratetracontane. For VTB and VTB + decane mixtures the new composite mixing rules showed encouraging results in predicting bubble point pressures and liquid phase densities.

Comparative study of the compositional characteristics of liquids derived by hydrotreating of Nigerian tar sand bitumen. I. Simulated distillation : Ukwuoma, O. Petroleum Science and Technology, 2002, 20 (5 & 6), 525–534

Ultracentrifugation was investigated as a means to obtain solvent-free bitumen from oil sand. The bitumen from three oil sands of varying grades was separated by placing the sands in specially designed tubes and centrifuging for 2 h at 198 000 g at 20 °C. For all grades of oil sand, approximately 70% of the bitumen was recovered. The recovered bitumen was compared to the residual remaining on the sand, and to that extracted by the conventional Soxhlet technique. The ultracentrifuged bitumen contained some emulsified water and a small amount of fine solids. The solvent-extracted material was water-free, but contained a small amount of residual solvent and fine solids. The ultracentrifuge caused some fractionation of the bitumen, resulting in a product slightly enriched in asphaltene components compared to the solvent-extracted material. The residual bitumen remaining on the sand was correspondingly slightly depleted in asphaltenes. However, as evidenced by gas Chromatographic simulated distillation data, ultracentrifugation did retain the light (180–220 °C) components of the bitumen which were lost during the solvent removal step following solvent extraction. Other analyses such as density, viscosity and elemental composition verified that ultracentrifugation resulted in some fractionation of bitumen components.

STUDY OF COMPOSITION OF NIGERIAN TAR SAND BITUMEN

Compositional characterization techniques developed for high-boiling heavy ends of petroleum have been applied to Nigerian tar sand bitumen. The bitumen was subjected to ion-exchange and ferric chloride coordination chromatography to separate acids, bases and neutral nitrogen compounds. The remaining Hydrocarbon plus fraction was separated into saturates, monoarmatics, diaromatics and polyaromatic plus polar compounds on dual packed column of silica - alumina gels. Simulated distillation data were also obtained for the bitumen and were used to plot a boiling point distribution curve. Results of the characterization are compared with results in literature for tar sand bitumens and petroleum. Comparison of the results with the Utah and the Athabasca bitumens provides a basis for the evaluation of the Nigerian bitumen because considerable information about the processing characteristics of the Athabasca bitumen have been reported by many researchers. Simulated distillation and chromatographic separation data indicate that the bitumen used in this present study closely resembles the Athabasca and the Utah tar sand bitumens with respect to hydrocarbon/non-hydrocarbon distribution, and the high-boiling petroleum fraction with respect to non-distilling portion. Information about the composition of bitumens and heavy oils is needed because of the prospect of using heavy oils including bitumens as energy sources.

Modeling Simulated Distillation. Influence of Catalyst Addition upon Model Parameters

Simulated distillation data of distillates produced by hydroconversion of a vacuum residue have been described as a two-component cumulative normal distribution function. The influence of catalyst addition upon calculated parameters of the model indicates that distillate fraction is produced through a consecutive mechanism. A modified three-component model has then been applied. It reveals that catalyst limits the extent of the first bond cleavage step and reduces the yield of light distillate. Furthermore, the distribution of hydrogen consumption is strongly affected by catalyst addition, which favors hydrogen incorporation in distillate.

Modeling Simulated Distillation: A Tool for the Evaluation of Hydroconverted Petroleum Residues

Simulated distillation, commonly applied to the characterization of complex products issued from the conversion of heavy petroleum fractions, provides information concerning the yield of distinct classes of distillable products. A simple modeling of simulated distillation data has been applied to several distillates obtained by hydroconversion of a vacuum residue. This model gives access to characteristic parameters which allows a description of this complex mixture in terms of two distinguishable components. The lighter one is produced through two simultaneous mechanisms, involving the rupture of substituted carbon positions and a symmetrical cleavage of the resulting molecules. The remaining component is representative of the initial feed and is preserved in a slightly modified state up to high level of conversion.

Preparation of bitumen from oil sand by ultracentrifugation

Ultracentrifugation was investigated as a means to obtain solvent-free bitumen from oil sand. The bitumen from three oil sands of varying grades was separated by placing the sands in specially designed tubes and centrifuging for 2 h at 198 000 g at 20 °C. For all grades of oil sand, approximately 70% of the bitumen was recovered. The recovered bitumen was compared to the residual remaining on the sand, and to that extracted by the conventional Soxhlet technique. The ultracentrifuged bitumen contained some emulsified water and a small amount of fine solids. The solvent-extracted material was water-free, but contained a small amount of residual solvent and fine solids. The ultracentrifuge caused some fractionation of the bitumen, resulting in a product slightly enriched in asphaltene components compared to the solvent-extracted material. The residual bitumen remaining on the sand was correspondingly slightly depleted in asphaltenes. However, as evidenced by gas Chromatographic simulated distillation data, ultracentrifugation did retain the light (180–220 °C) components of the bitumen which were lost during the solvent removal step following solvent extraction. Other analyses such as density, viscosity and elemental composition verified that ultracentrifugation resulted in some fractionation of bitumen components.

Calculation of High Temperature Crude-Oil/Water/Vapor Separations Using Simulated Distillation Data

Summary High-temperature crude-oil/water/vapor separation takes place in steamflooding and in-situ combustion processes. It also takes place in hydrocarbon recovery from deep volatile oil and condensate reservoirs. A practical procedure that uses the Holland and Welch method and sirilulated distillation data was developed to calculate crude-oil/water/vapor separations at 387 and 456°F [197 and 236°C]. The overhead yields obtained from the calculations were expressed as a function of the steam distillation factor. The Vw/Voi results were compared with laboratory crude-oil steam distillation data. The approach satisfactorily predicted the overhead yields of 13 out of 16 crude oils with an average error of 12% (±3.6% in yield). This is within experimental error of crude-oil steam distillation. Twelve pseudocomponents of crude oils were selected and characterized with simulated distillation data for the calculations. The physical properties of the pseudocomponents were determined from existing correlations and from matching laboratory steam distillation data. The use of simulated distillation data eliminates the uncertainty and assumptions normally involved in the selection of crude oil pseudocomponents with U.S. Bureau of Mines distillation data, and thus improves the reliability of the proposed computational approach. The proposed approach eliminates the need to conduct experimental steam distillation tests if simulated crude oil distillation data are available. It is easy and fast to calculate the overhead yields ahd densities without use of the equation of state (EOS) and uncertain pseudocomponent critical properties and interaction parameters. The proposed approach will provide useful information for the numerical simulation and design of thermal recovery processes and for the prediction of hydrocarbon recovery from high-temperature volatile oil and condensate reservoirs.

Application of the “cooled needle” technique to split and splitless sampling onto capillary columns

AbstractCooled needle sampling using syringes was applied to splitless injection and to simulated distillation analyses. Slight changes of the construction of the previous device are also described. The changes concern the temperature profile within the injector and especially the vaporization insert. Even with the low carrier gas flow through the injector during splitless injection, discrimination by component volatility can be avoided. Precision and accuracy of simulated distillation data obtained with split sampling also can be improved by the cooled needle technique.