Bitumen characterization

The elemental analysis of oil sand bitumen (extra heavy oil) has also been widely reported (Speight, 1990), but the data suffer from the disadvantage that identification of the source is too general (i.e., Athabasca bitumen which covers several deposits) and is often not site specific. In addition, the analysis is quoted for separated bitumen, which may have been obtained by any one of several procedures and may therefore not be representative of the total bitumen on the sand. However, recent efforts have focused on a program to produce sound, reproducible data from samples for which the origin is carefully identified (Wallace et al., 1988). It is to be hoped that this program continues as it will provide a valuable database for tar sand and bitumen characterization. 

This test attempts to characterize the brittleness of bitumen at low temperatures. It consists of measuring the temperature at which fissures appear on a bitumen film spread on a blade as it is repeatedly flexed. This test is delicate and of questionable reliability, but it is currently the only one that allows the elastic behavior of bitumen on decreasing temperature to be characterized. It is standardized in France (T 66-026). 

Roofs are a basic element of shelter from inclement weather. Natural or hewn caves, including those of snow or ice, ate early evidence of human endeavors for protection from the cold, wind, rain, and sun. Nomadic people, before the benefits of agriculture had been discovered and housing schemes developed, depended on the availabiUty of natural materials to constmct shelters. Portable shelters, eg, tents, probably appeared early in history. Later, more permanent stmctures were developed from stone and brick. SaUent features depended strongly on the avadabihty of natural materials. The Babylonians used mud to form bricks and tiles that could be bonded with mortars or natural bitumen. Ancient buildings in Egypt were characterized by massive walls of stone and closely spaced columns that carried stone lintels to support a flat roof, often made of stone slabs. 

Macpherson T, CW Greer, E Zhou, AM Jones, G Wisse, PCK Lau, B Sankey, MJ Grossman, J Hawari (1998) Application of SPME/GC-MS to characterize metabolitres in the biodesulfurization of organosulur model compounds in bitumen. Environ Sci Technol 32 421 26. 

With free radical initiator added (e.g., H202), the reaction takes minutes to complete. Based on the surfactant vesicles characterization derived from current investigations, it is suggested that these surfactants could retain their effectiveness necessary for bitumen recovery in the reservoir environment for a number of years. 

Heavy oils and bitumens are characterized by the presence of large molecules, the asphaltenes, which among their complex molecules also present metal-containing moieties. Typical metals present in petroleum comprise various species (e.g., Ni, V, Fe, Al, Na, Ca, and Mg), which are particularly accumulated in the asphaltene fraction of crude oil [382-384],... 

MacPherson, T. Greer, C.W. Zhou, E., et al., Application of SPME/GC-MS to Characterize Metabolites in the Biodesulfurization of Organosulfur Model Compounds in Bitumen. Environmental Science Technology, 1998. 32(3) pp. 421—426. 

The characterization of a novel series of biomarkers is illustrated with the g 7 2-dialkylalkanes in bitumen from a hydrothermal system on the Mid-Atlantic Ridge. The total bitumen consists of hydrocarbons, a major UCM (unresolved complex mixture of branched and cyclic compounds) and mature biomarkers (e.g. hopanes) (Fig. 13a). The bitumen contains a series of cyclopentylalkanes Cfi 2n) that range from n = 14 to 34, with only even-chained pseudohomologs and a concentration maximum (Cmax) at n = 18. Their source is biogenic, based on the presence of only even-carbon number homologs, but the precursors are unknown. 

A. Zandona, 0. J. Busch, L. E. Hettinger, W. P., Jr. "Reduced Crude Conversion Symposium on Production, Characterization and Processing of Heavy Oils, Tar Sand Bitumens, Shale Oils and Coal-Derived Liquids", University of Utah, 1981. 

The bitumen in its raw state has an API gravity of 8.3 and is characterized by low hydrogen to carbon ratios, 1.5, and high sulphur content,... 

Bitumen traces in ceramic vessels from Neolithic Iran, 137-151 pottery sherds, sampling and characterization, 141-142 Black willow, charred, infrared spectra, 63,64/... 

Isotopic characterization SI3C and SD values, asphaltene in bitumen samples, 146, 148/ 149/... 

Sulfur compounds in the gas oil fractions from two bitumens (Athabasca oil sand and Cold Lake deposit)> a heavy oil (Lloydminster) from Cretaceous reservoirs along the western Canada sedimentary basin, and a Cretaceous oil from a deep reservoir that may be mature (Medicine River) are investigated. The gas oil distillates were separated to concentrates of different hydrocarbon types on a liquid adsorption chromatographic column. The aromatic hydrocarbon types with their associated sulfur compounds were resolved by gas chromatographic simulated distillation and then by gas solid chromatography. Some sulfur compounds were further characterized by mass spectrometry. The predominant sulfur compounds in these fractions are alkyl-substituted benzo- and dibenzothiophenes with short side chains which have few dominant isomers. 

Analytical separation and spectroscopic techniques normally used for petroleum crudes and residues were modified and used to characterize coal liquids, tar sands bitumens, and shale oils. These techniques include solvent extraction, adsorption, ion-exchange, and metal complexing chromatography to provide discrete fractions. The fractions are characterized by various physical and spectroscopic methods such as GLC, MS, NMR, etc. The methods are relatively fast, require only a few grams of sample, provide compound type fractions for detailed characterization, and provide comparative compositional profiles for natural and synthetic fuels. Additional analytical methods are needed in some areas. 

The aromatic fraction accounts for almost half of the bitumen with the largest contribution made by the di-+ triaromatics (Table II). The aromatic fractions were further characterized by a XH NMR spectroscopic technique. This method, developed for petroleum crudes and fractions, calculates from the NMR spectrum a set of average parameters used to describe an average molecule. In this method, three assumptions are necessary which place constraints on its applicability. 

Advances in petroleum characterization at the molecular structure level by GC-MS methods renewed interest in OSC. Within the past few years, at least one-thousand new and novel OSC that previously were not known to be present in petroleum and bitumens have been reported. Tentative molecular structures inferred from GC-MS and other techniques have been confirmed in many cases by synthesis of authentic reference-compounds. The difficult and time-consuming synthetic work has been crucial in validating many of the novel structures. Another key finding has been that immature bitumens and crude oils (samples that have not received significant thermal stress) differ markedly from the previously known OSC in that they have carbon-skeletons resembling ubiquitous biomarker hydrocarbons (e.g., n-alkanes, isoprenoid alkanes, steranes, and hopanes). This similarity, of course, suggests that the hydrocarbons and OSC have common biogenic precursors. 

Characterization of Feedstock and Catalysts. The elemental analysis and physical properties of various feedstocks used in this study are given in Table I. The data show that the virgin bitumen contains... 

The conventional approach to asphalt analysis has been to extract the bitumen with an organic solvent and then to characterize bitumen and minerals separately. Sulfur content and melting point are commonly measured properties of bitumen. Minerals are generally screened and then subjected to simple quantitative tests. Measurement of weight loss on ignition helps to distinguish between calcium carbonate, which loses... 

Standardization of analytical techniques has helped greatly to compare asphalts of diflFerent areas and diflFerent periods. Repeated extractions with boiling toluene has improved consistency of data, whether or not it is the best way of separating bitumen and minerals. Liquid chromatographic analysis not only determines the amount of minerals suspended in the bitumen but also provides fractions suitable for further characterization. X-ray diffraction promises to improve vastly analysis of the minerals. No good way of resolving whatever usually small amounts of insoluble organic matter may be present has been devised. 

To test these hypotheses, a tar sand bitumen containing 20 wt % pentane asphaltenes was characterized and processed by hydropyrolysis before and after removal of asphaltenes. Product yields and structure were determined and the influence of asphaltenes on results was determined by inferrence. Feedstocks and products were characterized according to elemental analysis, physical properties, simulated distillation, and carbon-type analysis. Inferences made in this study are discussed in the context of the reported literature. 

The virgin bitumen and fractions were characterized by 13C NMR. Results shown in Figure 1 show that the spectra of the maltenes and the virgin bitumen are virtually superimposable. The high resolution spectra reveal several resolved peaks in the saturates region attributable to n-alkyl species, some of which are of notably lower intensity in the maltenes spectrum, but in general, the vast majority of the saturates carbon (>80%) is found under the envelope and is probably due to complex alicyclic and/or isoparaffin structures. These results are consistent with an earlier observation (1) that saturated hydrocarbons from Uinta Basin bitumen are high in naphthenes and low in free paraffins. 

The structure and chemistry of tar sand bitumen asphaltenes were studied indirectly by inference from processing and characterization of virgin bitumen and deasphaltened bitumen (maltenes). Results differ significantly from those derived from characterization of asphaltenes as isolated... 

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