Composition, hydrocarbon

The quality and quantity of fluids produced at the wellhead is determined by hydrocarbon composition, reservoir character and the field development scheme. Whilst the first two are dictated by nature the latter can be manipulated within technological and market constraints. 

Gas Water and hydrocarbon dew point, hydrocarbon composition, contaminants content, heating value. 

A container full of hydrocarbons can be described in a number of ways, from a simple measurement of the dimensions of the container to a detailed compositional analysis. The most appropriate method is usually determined by what you want to do with the hydrocarbons. If for example hydrocarbon products are stored in a warehouse prior to sale the dimensions of the container are very important, and the hydrocarbon quality may be completely irrelevant for the store keeper. However, a process engineer calculating yields of oil and gas from a reservoir oil sample will require a detailed breakdown of hydrocarbon composition, i.e. what components are present and in what quantities. 

The cetane number of a fuel depends on its hydrocarbon composition. In general, normal paraffins have high cetane numbers, isoparaffins and aromatics have low cetane numbers, and olefins and cycloparaffins fall somewhere in between. Diesel fuels marketed in the United States have cetane numbers ranging between 35 and 65. Most manufacturers specify a minimum cetane number of 40—45. 

The increase in fuel viscosity with temperature decrease is shown for several fuels in Figure 9. The departure from linearity as temperatures approach the pour point illustrates the non-Newtonian behavior created by wax matrices. The freezing point appears before the curves depart from linearity. It is apparent that the low temperature properties of fuel are closely related to its distillation range as well as to hydrocarbon composition. Wide-cut fuels have lower viscosities and freezing points than kerosenes, whereas heavier fuels used in ground turbines exhibit much higher viscosities and freezing points. 

Fig. 5 shows the effects of the gas residence time on the hydrocarbon composition. The numerical simulation was carried out by the refined model. The calculated results are in good agreement with the experimental results. It should be noted that the measured gas composition only at a residence time of 20 ms was used for the parameter fitting. Nevertheless, the calculated hydrocarbon composition agrees with the experimental results at residence times shorter than 20 ms. 

At a pressure of 10 bar, determine the bubble and dew point of a mixture of hydrocarbons, composition, mol per cent n-butane 21, n-pentane 48, n-hexane 31. The equilibrium K factors can be estimated using the De Priester charts in Chapter 8. 

Daccord, G., Lemanczyk, R., and Vercaemer, C. "Method for Obtaining Gelled Hydrocarbon Compositions, the Compositions According to Said Method and Their Application in the Hydraulic Fracturing of Underground Formations," US Patent 4,507,213(1985). 

Both direct and indirect methods were tested in the Lisbon area. Direct methods include the assessment of hydrocarbon compositional signatures in surface soils, outcrop fracture-fill soils and mosses, and 6-ft (2 m) deep free-gas samples. Indirect methods pertain to the major and trace element chemistry of soils to look for alteration effects resulting from hydrocarbon microseepage. 

Figure 2. General scheme of hydrocarbon formation as a function of burial of the source rock. The evolution of the hydrocarbon composition for three compound classes is shown schematically in the insets. Depths are only indicative and may vary according to the actual geological situation (from Engel and Macho, 1993).

Naphthalene and its homologs are less acutely toxic than benzene but are more prevalent for a longer period during oil spills. The toxicity of different crude oils and refined oils depends not only on the total concentration of hydrocarbons but also the hydrocarbon composition in the water-soluble fraction (WSF) of petroleum, water solubility, concentrations of individual components, and toxicity of the components. The water-soluble fractions prepared from different oils wiU vary in these parameters. Water-soluble fractions (WSFs) of refined oils (e.g.. No. 2 fuel oil and bunker C oil) are more toxic than water-soluble fraction of crude oil to several species of fish (killifish and salmon). Compounds with either more rings or methyl substitutions are more toxic than less substituted compounds, but tend to be less water soluble and thus less plentiful in the water-soluble fraction. 

By limiting the amount of hydrocarbons that are lower boiling than the main component, the vapor pressure control is reinforced. Tests are available for vapor pressnre 100°F (38°C) (ASTM D1267) and at 113°F (45°C) (IP 161). The limitation on the amonnt of higher-boiling hydrocarbons supports the volatility clause. The vapor pressure and volatility specifications will often be met automatically if the hydrocarbon composition is correct. 

Hydrocarbon composition is also determined by mass spectrometry, a technique that has seen wide use for hydrocarbon-type analysis of naphtha and gasoline (ASTM D2789) as well as for the identification of hydrocarbon constituents in higher-boiling naphtha fractions (ASTM D2425). 

More than 100 compounds are released in the atmosphere of urban areas by automobiles, and there is a close relation between the atmospheric hydrocarbon composition and the composition of gasolines and automobile exhausts. The full range of compositions of gasolines has been reported by Sanders and Maynard.They identified 180 of the 240 compounds separated by capillary-column gas chromatography. Detailed fiiel compositions were reported by other investigators, and exhaust hydrocarbon compositions were reported by Neligan et a/.,McEwen, and, more recently. Papa et Jacobs, ... 

Dishart, K. T. Exhaust hydrocarbon composition. Its relation to gasoline composition. Proc. Amer. Pfetrol. Inst. 50 514-540, 1970. 

Hydrocarbon distillates in the gas oil range ( diesel or derv ) are subject to duty when used as a road fuel. Gas oil, which is often identical to diesel oil in hydrocarbon composition, is exempt from duty when used for stationary machines. In order to prevent its misuse as a road fuel, gas oil is marked with a mixture of 1,4-dfhydroxyanthraquinone (quinizarin), 2-fiirfuraldehyde (furfural) and a red dye. An automatic method for the extraction, identification and determination of quinizarin in gas oil has been used hy the Laboratory of the Government Chemist (LGC) for some years. The presence of furfiiral provides evidence for legal prosecution and the numbers of analyses ordered in the UK merit automatic analysis. 

The hydrocarbon composition of the fuel can influence sensitivity. Fuels containing higher percentages of unsaturated and aromatic compounds typically have high sensitivity. Linear paraffins in fuels are less sensitive, while highly branched paraffins can be more sensitive. TABLE 3-4 contains information on the sensitivity of various fuel components. 

The relation of the constitution of saturated petroleum fractions to their insecticidal efficiency was shown in the case of a single insect species in a previous paper (9). To extend this study the Citrus Experiment Station of the University of California, the Shell Oil Co., and the New York State Agricultural Experiment Station cooperated to include other species and to examine the insecticidal properties of various hydrocarbon compositions derived directly or indirectly from petroleum as well as synthetic hydrocarbons of known constitution. Part of the program planned for the New York Station consisted of ... 

Figure 4. Correlations between Minimum Effective Dosage of Hydrocarbon Compositions and Molecular Weight and Viscosity...

Figure 7. Correlation between Minimum Effective Dosages of Various Hydrocarbon Compositions and Molecular Weight and...

The material aid and cooperation of the Shell Oil Co., in support of this research program is gratefully acknowledged. The authors would also like to express their appreciation to A. M. Boyce, L. A. Riehl, and other members of the staff of the Citrus Experiment Station, Riverside, Calif., for their active support and cooperation in the program. Thanks are also due to M. R. Fenske and R. W. Schiessler of the Pennsylvania State College for their advice and guidance in the preparation of the hydrocarbon compositions utilized in this work. 

Petroleum oils are widely used in the treatment of citrus crops in California. They have proved to be the most efficient insecticide per unit of cost for most of the dominant pests of citrus in this area. In an effort to improve oil sprays from the standpoint of both tree safety and insecticidal effectiveness, the research on oil sprays at the University of California Citrus Experiment Station has been intensified. Part of this new effort has involved close cooperation with other laboratories, particularly with the New York State Agricultural Experiment Station at Geneva. The same petroleum fractions and other hydrocarbon compositions were tested simultaneously against citrus and deciduous fruit pests. This coordinated approach has been mutually advantageous, and it is expected that it will lead to an understanding of the fundamental principles involved in the use of hydrocarbon oils as insecticides in general. 

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