Compound types and properties of Utah and Athabasca tar sand bitumens

Properties and compound types were examined in detail for tar-sand bitumens representative of four major deposits in Utah and Alberta. Methods for bitumen extraction, separation, and compound type (functional group) analysis are presented. Results of the analyses are compared with each other and with results in the literature for tar-sand bitumens and petroleum. Comparison of the results of Utah bitumens with the Athabasca bitumen provides a basis for evaluation of the Utah bitumens because considerable information about the processing characteristics of the Athabasca bitumen has been reported. Simulated distillation and Chromatographic separation data indicate that, in general, the tarsand bitumens most closely resemble Wilmington petroleum with respect to hydrocarbon/non-hydrocarbon distribution, especially in the non-distilling portion (the distillable portions, mainly hydrocarbons, are similar for all samples). Tar-sand bitumens were also shown to differ significantly from one another, principally in the amounts and kinds of heteroatomic compound types present. This information is important because of the effects that composition has on recovery and refining processes. Analyses of the chemical functionalities also provide a basis for developing correlations between bitumen composition and the recovery and processing characteristics of the bitumen.     

E.s.r. of Alberta tar sand bitumen and thermally hydrocracked products

A study of the vanadium and free radical species present in Athabasca bitumen and thermally upgraded products from a hydrocracking pilot plant was carried out. The samples were separated into asphaltene, chloroform resin, tetrahydrofuran resin and oil components, and the fractions studied by electron spin resonance. All samples except the oil fraction contained vanadyl (VO²⁺) ions and free radicals. It was found that even mild thermal treatment of bitumen produced considerable redistribution of vanadyl groups among the fractions, whereas at the severest hydrocracking conditions 94 wt% of all vanadyl groups were associated with the asphaltene fractions compared with only 58.5 wt% in the original bitumen. As the hydrocracking severity increased, the asphaltene vanadyl concentration initially increased above the value for unreacted bitumen and then decreased to a lower value. On the other hand, the resin vanadyl concentration decreased continuously and more rapidly than asphaltene vanadyl concentration. This indicates that vanadyl groups associated with the resin fractions are less stable than those associated with the asphaltenes and also suggests that transfer of vanadyl groups from the resin fractions to asphaltene predominates at low severity while removal of vanadyl groups predominates at high severity. The average spin Hamiltonian parameters showed that the chemical environment of vanadyl ions in the THF resins was significantly different from the vanadyl environment in the other two fractions.     

低温煤焦油中特定芳烃组分的选择性分离

以研究低温煤焦油中特定芳烃组分的选择性分离为目标, 通过预处理分离酚类化合物和富集特定芳烃组分, 采用多元溶剂萃取方法选择性分离芳烃和非芳烃组分, 采用Hansen溶度参数理论进行多元溶剂的设计和萃取条件的优化。结果表明, 溶剂对原料焦油的选择性随Hansen溶度参数“距离”(R_a)增加而增大, 萃取能力则相反。研究得到的多元萃取剂是含水量为体积分数6%的N,N-二甲基甲酰胺溶液, 优化萃取条件是温度25℃、剂/油比6:1。萃余物经多次萃取进一步分离芳烃组分, 萃出物经甲酰胺多次萃取以分离出杂环化合物和极性组分。芳烃组分在最终分离产物中的质量分数为94%, 其总萃取收率为95%。另外非芳烃化合物、杂环化合物和其他极性组分也在本过程中得到了有效富集。     

Non-isothermal programmed pyrolysis studies of oil sand bitumens and bitumen fractions: 1. Athabasca asphaltene

Characteristic pyrolysis thermograms for 12 gases have been obtained for Athabasca asphaltene, using a combination of non-isothermal, programmed pyrolysis (ambient to 1200 K at 3 K min^?1) and gas chromatography. Such thermograms provide information for the characterization of asphaltenes in the form of gas yields, specific rates and Arrhenius kinetic parameters. All thermograms comprised more than one peak. These peaks lie in distinct temperature zones and are associated with primary and secondary cracking and coking reactions. Useful insights into the structure of Athabasca asphaltene and, indirectly, the composition of its pyrolytic cokes have been obtained. The present results provide a body of useful reference material which may be useful for monitoring processes, which may chemically modify the asphaltene fraction of bitumens and heavy oils, and for comparative studies of asphaltenes from a variety of sources.     

Behavior of tar sand bitumen with paraffinic solvents and its application to separations for athabasca tar sands

A study was made of the dissolution of tar sand bitumen using low-molecular-weight paraffinic solvents at essentially ambient temperatures. The experimental data were obtained using the spinning disc technique, liquid-fluidized beds, and direct particle-size analysis of the insolubles. The results are consistent with a mechanism where the paraffins leach the soluble oil from the bitumen and leave behind a porous network of insoluble asphaltenes. This phenomenon of oil diffusing through an asphaltene layer was modeled using Fick's law for unsteady-state diffusion. An understanding of the mechanism of bitumen extraction with paraffins and also the effect of fluid mechanics in the tar sand system have been applied to obtain a novel separation of deasphalted oil and asphaltenes from Athabasca tar sands. This new separation technique has the potential of simplifying downstream processing for the bitumen and also of avoiding environmental problems associated with the present tar sand extraction technology.     

Structural analysis of tars from fluidized bed pyrolysis of coal:: 2. 1H n.m.r. and i.r. spectroscopy

¹H n.m.r. and i.r. spectroscopy of aromatic and polar fractions of two tars from the rapid pyrolysis of coal in a fluidized bed at 550 °C show that the nature of the products depends on the reactivity of the pyrolysis gas. In the presence of flue gas, there is more thermolysis leading to shorter and fewer alkyl side chains and generation of lower molecular mass material. Pyrolysis by means of char gasification gas results in much less thermolysis of the tar but leads to secondary reactions which can be interpreted by a radical mechanism involving the reactive constituents of the char gas.     

Reactions of saturated hydrocarbons I. Oxidation of isoparaffins by chromic acid

Measurements of the rate of reduction of chromium(VI) oxide in acetic acid–acetic anhydride solution by 2-methyl-pentane, 3-methylpentane, 2,3-dimethylbutane and 2,4-dimethylpentane show that the initial rate depends on the number and nature of carbon atoms in the hydrocarbon. When steric or other interaction effects prevail between adjacent atoms or groups in the molecule, these effects also influence the rate. The values obtained for the oxidation rates agree with those calculated from a proposed expression (Rn_p+R'n_s+R'n_t)/(n_p+n_s+n_t) based on the formula of Chambers & Ubbelohde.     

Reactions of saturated hydrocarbons II. oxidation of cycloparaffins by chromic acid

The rate of reduction of chromium(VI) oxide in acetic acid–acetic anhydride solution by a number of cyclo-paraffins has been measured. The values obtained agree with those calculated from the proposed expression (Rn_p+R'n_s+R''n_t)/(n_p+n_s+n_t), based on the Chambers & Ubbelohde equation, with some deviations. Trans-1,2-dimethylcyclohexane oxidised at a rate slower than expected whilst cyclopentane and methylcyclopentane showed a rate higher than the calculated value. A tentative explanation is given based on confornational analysis and strain energy considerations.     

Characterization and utilization of hydrotreated products from the Whiterocks (Utah) tar sand bitumen-derived liquid

The bitumen-derived liquid produced in a fluidized-bed reactor from the Whiterocks tar sand was hydrotreated over a sulphided Ni-Mo/Al₂O₃ hydrodenitrogenation catalyst in a fixed-bed reactor. The process variables studied were temperature (617–680 K), pressure (11.0–17.1 MPa) and liquid hourly space velocity (0.18–0.77 h⁻¹). The feed and the hydrotreated liquid products were analysed by gas chromatography-mass spectrometry analyses. The compounds identified in the bitumen included isoprenoids; bicyclic, tricyclic, and tetracyclic terpenoids; steranes; hopanes; and perhydro-β-carotenes. Normal and branched alkanes and alkenes and partially dehydrogenated hydroaromatics were identified in the bitumen-derived liquid. Comparison of the compounds identified in the bitumen and the bitumen-derived liquid indicated that the dealkylation of long alkyl side chains 0to form - and isoolefins and the cleavage of alkyl chains linking aromatic and hydroaromatic clusters were the dominant pyrolysis reactions. Monoaromatic hydrocarbons were the predominant aromatic species in the hydrotreated product. The properties of the jet fuel fractions from the hydrotreated products met most of the jet fuel specifications. The cetane indices indicated that these fractions would be suitable for use as diesel fuels.     

煤焦油中渣相的分析及应用

分析了煤焦油中渣相的性质,其具有很强的反应性,可作为一些沥青反应添加剂使用,并在应用方面做了一些阐述.     

Separation of saturated hydrocarbons from coal by treatment with water at supercritical parameters

The treatment of coals of various degrees of metamorphism in supercritical water (SCW) over the temperature region 380–800°C was studied. The yields and compositions of liquid products obtained by treatment in SCW were determined. These data were compared with the results of the semicoking of the above coals.     

Densities of hydrocarbons in their saturated vapor and liquid states

The Sum and differences of the saturated vapor and liquid densities of 23 hydrocarbons were used to develop the following reduced density relationships for these saturated states The hydrocarbons considered included n-parafins, olefins, diolefins, naphthenes, and aromatics. Constants β, γ, and δ, and exponent n were found to be dependent on,. Equation (a) can reproduce liquid densities with an overall average deviation of 1.1 % over the entire temperature range, while Equation (b) was found to apply only in the interval 0.900 ≤ T_R ≤ 1.00 with an average deviation of 2.2%. For temperatures of T_k < 0.90, the saturated vapor density was found to depend on temperature as follows where k and m were also found to be Z_c dependent. Values calculated using Equation (c), when compared with 81 available experimental densities for 12 hydrocarbons, produced an average deviation of 3.0%.     

Structure of amorphous polyethylene from n.m.r. line shape analysis and MAR-n.m.r.

Based on results of proton nuclear magnetic resonance measurements with magic angle rotation (MAR n.m.r.), the line of amorphous polyethylene in conventionally measured proton n.m.r. spectra is described as a convolution of a basic narrow line-shape function S(v) with an orientation-dependent dipolar broadening function G(v). With this approach it is possible to describle to describe the broadline n.m.r. spectrum of polyethylene as a superposition of the crystalline component and of a single amorphous phase. The fit of experimental and computed spectra, and the parameters obtained by this type of line-shape analysis are discussed for a series of polyethylene samples of different crystallinity.     

Isolation of prime value products from crude xylenol fraction of noncaking coal-derived tar acids

An efficient method for the separation of prime value products from crude xylenol fraction of noncaking coal-derived tar acids involving suitable distillation technique is described. The feed as well as the products was analysed by gas chromatography (G.C.). The crude xylenol comprising a number of close-boiling phenolic compounds was fractionated under reduced pressure to yield three cuts, viz. cresols (30.7%), xylenols (31.2%) and dihydric phenols (23.3%). The dihydric phenols fraction termed as high boiling tar acids (HBTA) was found to contain significant amounts of catechol (6.4%), methyl catechols (32.3%), resorcinol (12.7%) and methyl resorcinols (8.6%). Catechol together with its homologues and resorcinol with its homologues were isolated from the HBTA. These products, not available from the HBTA of metallurgical coke plants, have been shown to offer distinct marketing advantages. A conceptual scheme for the treatment of crude xylenol as well as application pattern of various products obtainable from the crude mixture is presented.     

Nitrogen compound distribution in middle distillate fuels derived from petroleum,oil shale,and tar sand sources

Nitrogen compounds present in crude sources constitute serious problems both for producers and consumers. For producers, these compounds are responsible for poisoning catalysts during the refining processes. For consumers, these compounds are responsible for the degradation observed in fuels during storage and handling. The quality of petroleum, as measured by °API gravity, continues to decrease in quality. This, coupled with the inevitable use of other crude sources, if used in quantity will further decrease the stability of middle distillate fuels. In this article we present our method for the separation and quantitation of the slate of nitrogen compounds present in middle distillate fuels derived from petroleum, oil shale and tar sand sources. Results from our laboratory indicate that of all of the nitrogen compounds present in middle distillate fuels, the indole type structure is the most deleterious.     

Evaluation of the aromatic structure of coal tar pitch by solid and solution state n.m.r.

Rapid magic angle spinning has been used to obtain sideband-free high field ¹³C n.m.r. spectra of coal tar pitches in the solid state. However, the unfavourable cross-polarization and ¹H relaxation characteristics make it difficult to accurately estimate concentrations of quaternary aromatic carbon using the dipolar dephasing method. The concentrations of bridgehead aromatic carbon in the whole pitch and toluene-insoluble fraction investigated were deduced using a combination of solid and solution state n.m.r. and elemental analyses.     

Quantitative solid-state C n.m.r. measurements on cokes, chars and coal tar pitch fractions

Bloch decay or single pulse excitation (SPE) ¹³C n.m.r., generally recognized as the best approach to obtain quantitatively reliable aromaticity values and other skeletal parameters for coals, was applied to partly carbonized coal samples, a biomass char and the toluene-insolubles from a coal tar and a corresponding pitch. As found previously for coals, the aromaticities and non-protonated carbon concentrations were generally higher than those estimated by cross-polarization (CP). Furthermore, in terms of accumulation times, the shorter ¹³C T₁'s of low-temperature chars makes SPE a more efficient technique than for coals. The higher concentrations of paramagnetic centres responsible for the shorter ¹³C T₁'s still result in observability of 75% of the carbon in the chars by the SPE technique. The ratios derived from the SPE measurements agree well with those obtained from elemental analysis.     

Characteristics of bitumens extracted from Italian bituminous rocks and shales

The soluble portion of representative samples from Italian bituminous rocks and shales were studied by n.m.r. spectrometry in the liquid state and by thermoanalytical techniques. The extracted bitumens have a variety of characteristics and also differ from analogous foreign material. One of the samples, from the Ragusa, Sicily area, is of considerable interest from the point of view of exploitation, as it is soluble in benzene and almost totally distillable in the 150–500 °C range.