Analysis of petroleum fractions

Stenzel H, Rodicker H. 1991. Results of substance groups and structural groups analysis of petroleum fractions and their application in estimating the correlation for predicting properties. Chemische Technik 43 344-346. 

Karlsen, D. a. Larter, S. R. 1991. Analysis of petroleum fractions by TLC-FID Applications to petroleum reservoir description. Organic Geochemistry, 17, 603—617. 

Sofer, Z. (1980) Preparation of carbon dioxide for stable isotope analysis of petroleum fractions. Analyt. Chem., 52, 1389-91. 

Karlsen, D.A. barter, S.R. (1991). Analysis of Petroleum Fractions by TLC-FID Applications to Petroleum Reservoir Description. Organic Geochemistry, Vol.l7, No.5, pp. 603-617... 

Riazi, M.R., Daubert, T.E. 1986. Prediction of molecular type analysis of petroleum fractions and coal liquids. Ind. Eng. Chem. Process Des. Dev. 25(4) 1009-1015. 

In order to simplify the analysis of petroleum and its fractions, other preliminary separation techniques are employed, aiming generally to separate certain classes of components. 

Although distillation and elemental analysis of the fractions provide a good evaluation of the qualities of a crude oil, they are nevertheless insufficient. Indeed, the numerous uses of petroleum demand a detailed molecular analysis. This is true for all distillation fractions, certain crude oils being valued essentially for their light fractions used in motor fuels, others because they make quality lubricating oils and still others because they make excellent base stocks for paving asphalt. 

Once the sample preparation is complete, there are several approaches to the analysis of petroleum constituents in the water and soil (1) leachability or toxicity of the sample, (2) the amounts of total petroleum hydrocarbons in the sample, (3) petroleum group analysis, and (4) fractional analysis of the sample. These methods measure different petroleum constituents that might be present in petroleum-contaminated environmental media. 

Weisman, W. 1998. Analysis of Petroleum Hydrocarbons in Environmental Media. Total Petroleum Hydrocarbons Criteria Working Group Series, Vol. 1. Amherst Scientific Publishers, Amherst, MA.(See also Vol. 2, Composition of Petroleum Mixtures, 1998 Vol. 3, Selection of Representation Total Petroleum Hydrocarbons Fractions Based on Fate and Transport Considerations, 1997 Vol. 4, Development of Fraction-Specific Reference Doses and Reference Concentrations for Total Petroleum Hydrocarbons, 1997 and Vol. 5, Human Health Risk-Based Evaluation of Petroleum Contaminated Sites, Implementation of the Working Group Approach, 1999.)... 

The study of the catalytic cracking of pure hydrocarbons as a key to the interpretation of the catalytic cracking of petroleum fractions is predicated on the belief that most of the hydrocarbons present in petroleum can be allocated to relatively few simple classes. This belief is supported particularly by the accumulated results of API Project 6, originally titled The Separation, Identification, and Determination of the Constituents of Petroleum (now retitled Analysis, Purification, and Properties of Hydrocarbons ). For the sake of consistency of experimental conditions, the data reported are those of the... 

Data reporting (i.e., the statement of the results of the proximate analysis test methods) usually includes (in some countries but not in all countries) descriptions of the color of the ash and of the coke button. As an interesting comparison, the test for determining the carbon residue (Conradson), the coke-forming propensity of petroleum fractions and petroleum products (ASTM D-189 ASTM D-2416), advocates the use of more than one crucible. A porcelain crucible is used to contain the sample, and this is contained within two outer iron crucibles. This corresponds to the thermal decomposition of the sample in a limited supply of air (oxygen) and the measurement of the carbonaceous residue left at the termination of the test. 

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. 

The dilution methods of sample preparation of petroleum fractions for metal analysis are limited to the concentration of metals in each fraction. The dilution method is applicable for routine monitoring crude and lubricating oils, providing the concentration of metals is quantifiable using standard calibration curve, internal standard or standard addition method. The method is unsuitable for low concentration of metals especially as those can build up accumulatively, causing poisoning in all catalytic fractionation plants. The low concentration of toxic metals may be undetected by dilution methods and may escape monitoring if a more sensitive method is not used. 

The methods most commonly employed for the analysis of petroleum hydrocarbons in marine organisms (2-5) involve extraction with or without saponification, fractionation by column chromatography on silica gel... 

All experimental runs were made on a C4 feed of known composition. The feed composition ran from 37 to 40 wt % 1,3-butadiene. A typical analysis of this feed is shown in Table III. This composition is similar to C4 streams obtained by thermal cracking of petroleum fractions. 

Isoprenoids (terpanes), with a longer chain than pristane, have been detected in fossil fuels (see below the discussion on the analysis of petroleum). C25—C30 isoprane hydrocarbons were analysed in a number of methanogenic bacteria The C40 isoalkane, which was isolated from the saturated fraction of the bitumen of the Green River Shale (USA), is claimed to be the product of total saturation of carotenoids. The analysis of these polyhydrogenated carotenes (PHC) requires special GC high-temperature inert columns (see GC of high carbon number wax hydrocarbons). 

The application of mass spectrometry, including electron impact (El) studies, to the analysis of hydrocarbon fractions obtained from petroleum is as old as the earliest exploitation of the technique. Almost all of the ionization methods known have been applied to saturated hydrocarbons. The number of papers dealing with one or another aspect of the MS of alkanes and cycloalkanes is enormous. However, the computerized compilation of the mass spectra in libraries such as NBS makes the search easier ... 

Effect of Impurities on the Critical Solution Temperature. The addition of even a small amount of a third component to a two-liquid system will ordinarily alter the C.S.T. considerably. Thus, for example, the addition of 0.2 per cent of water to glacial acetic acid raises the C.S.T. with cyclohexane from 4.2 to approximately 8.2 C. Useful methods of analysis have been devised based on such observations. For example, the amount of deuterium oxide in water can be estimated by measuring the C.S.T. with phenol and the aromatic hydrocarbon content of petroleum fractions by the C.S.T. with aniline. In general, the C.S.T. will be raised if the added component is highly soluble in only one of the original components (salting out) and lowered if it is highly soluble in both. Such systems properly must be considered as three-component mixtures, however. 

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