Saturate-olefin-aromatic content

Nevertheless, this type of analysis, usually done by chromatography, is not always justified when taking into account the operator s time. Other quicker analyses are used such as FIA (Fluorescent Indicator Analysis) (see paragraph 3.3.5), which give approximate but usually acceptable proportions of saturated, olefinic, and aromatic hydrocarbons. Another way to characterize the aromatic content is to use the solvent s aniline point the lowest temperature at which equal volumes of the solvent and pure aniline are miscible. 

Naphthas boiling up to 185°C can be reformed at pressures up to 600 psig. Naphthas with final boiling point up to 240 C may be reformed at lower pressures. Higher olefin contents may be accepted provided that sufficient hydrogen is available in the recycle gas to saturate the feed in the desulfurization section. Higher aromatic contents may be accepted but tile catalyst life will be reduced. 

For gasoline, only approximate characterization parameters are provided, such as the octane number, the boiling point distribution, and the saturated hydrocarbons (alkanes), unsaturated hydrocarbons (olefins) and aromatics content. The content of contaminants, such as sulfur, is important. 

Usually, there is a large variation in results for olefins determined by the FIA method in different laboratories, as shown in Table 3. The olefins content varies from 1.1 to 6.2vol%, the aromatic content ranges from 34.4 to 44.4vol% and the saturate content from 54.3 to 63.5vol%. The SPE results, 60.8wt% for saturates, 4.3wt% for olefins and 34.9wt% for aromatics, fall well within the range of these round robin FIA test results. 

Lastly, we compared the olefin content in the commercial diesel DECSE from DOE (Department of Energy). It was determined by ASTM D1319 method in the US laboratory to be 2.3 vol%. The saturate and the aromatic contents measured by ASTM D5186 were 71.2 and 28.5 respectively. In comparison, SOAP results for this diesel were 72.1 wt% for saturates, 28. lwt% for aromatics and 1.8wt% for olefins. Analysis by SFC at Syncrude Research Ltd. rendered total saturates 71.2 wt% and total aromatics 28.8 wt%. 

In general terms, group-type analysis of petroleum is often identified by the acronyms for the names PONA (paraffins, olefins, naphthenes, and aromatics), PIONA (paraffins, Ao-paraffins, olefins, naphthenes, and aromatics), PNA (paraffins, naphthenes, and aromatics), PINA (paraffins, Ao-paraffins, naphthenes, and aromatics), or SARA (saturates, aromatics, resins, and asphaltenes). However, it must be recognized that the fractions produced by the use of different adsorbents will differ in content and will also be different from fractions produced by solvent separation techniques. 

Oil industry has a long history of application of NMR spectroscopy for characterization of crude oils, products and oil fractions. The methodology has been mainly ID proton- or carbon-detected experiments. Quantitative NMR and NMR experiments have been used in estimation of aromatic, olefin, naphtene and paraffin proportions in the samples. ° A more detailed characterization has been obtained using various ID carbon-detected experiments, like GASPE, CSE, QUAT and DEPT to obtain quantitative CH sub-spectra. " The goal of characterization of the oil fractions and quantification of certain structural features has been to find correlation between these features and the product properties (e.g. viscosity index, pour point). Due to environmental concerns oil companies are nowadays more interested in development of lubricant base oils that have low aromatic and olefin contents. Hydrogenation of unsaturated components also improves the stability of the base oils, which is an important property for the end-product. Quantitative analysis of a saturated oil fraction with NMR is a major challenge. When the oil fraction contains only aliphatic compounds, the spectrum width that contains the resonances narrows to ca. 1 ppm in the NMR spectrum and ca. 50 ppm in NMR spectrum. This causes excessive... 

No development of catalytic activity,however,was observed when pure HZSM-5 and GazOs+HZSM-S separated by a 0.5 cm long quartz wool bed were used as catalysts. From Table 2 it can also be seen that, after 1500 minutes on stream with propane the aromatic selectivity is enhanced by a factor of about 100 and there is a threefold increase in the total conversion compared with the HZSM-5 sample containing no Ga. While the methane yield does not change significantly, the content of saturated hydrocarbons increases steadily, reflected in the olefin/paraffin ratios shown in Table 2. Characteristic changes also occur in the isobutane/n-butane ratio. 

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