Petroleum group analysis

Petroleum group analyses are conducted to determine amounts of the petroleum compound classes (e.g., saturates, aromatics, and polars/resins) present in petroleum-contaminated samples. This type of measurement is sometimes used to identify fuel type or to track plumes. It may be particularly useful for higher-boiling products such as asphalt. Group-type test methods include multidimensional gas chromatography (not often used for environmental samples), high-performance 

Test methods that analyze individual compounds (e.g., benzene-toluene-ethylbenzene-xylene mixtures and PAHs) are generally applied to detect the presence of an additive or to provide concentration data needed to estimate environmental and health risks that are associated with individual compounds. Common constituent measurement techniques include gas chromatography with second-column confirmation, gas chromatography with multiple selective detectors, and gas chromatography with mass spectrometry detection (GC/MS) (EPA 8240). 

Many common environmental methods measure individual petroleum constituents or target compound rather than the entire signal from the total petroleum hydrocarbons. Each method measures a suite of compounds selected because of their toxicity and common use in industry. 

Eor organic compounds, there are three series of target compound methods that must be used for regulatory purposes  

EPA 500 series Organic Compounds in Drinking Water, regulated under the Safe Drinking Water Act. 

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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. 

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. 

Standard Test Method for Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the n-d-M Method. ASTM D3238-95 (2005). 

Nowhere is the contribution of spectroscopic studies more emphatic than in application to the delineation of structural types in the heavier feedstocks. This has been necessary because of the unknown nature of these feedstocks by refiners. One particular example is the n.d.M. method (ASTM D-3238) which is designed for the carbon distribution and structural group analysis of petroleum oils. Later investigators have taken structural group analysis several steps further than the n.d.M. method. 

Leendertse, J. J., et al.. Petroleum Refiner, in press. Structural Group Analysis of Petroleum... 

Petroleum group type analysis (not suitable for risk estimation) Group type analyses are performed to measure the amounts of individual petroleum classes of hydrocarbons (e.g. saturates, aromatics, polars). This type of measurement is typically used for heavier fractions and can be used to interpret or identify the type of oil (Fig. 6.5). 

Petroleum group type analysis (detailed review)... 

Data from colloid analysis show that the concentration of the dispersion medium may be related to the distillable fraction AG400, whereas the concentration of asphaltenes, or the total of asphaltenes and petroleum resins, determines the quantity of coke residue after pyrolysis. That portion of the sample which can be cracked, CR, will usually be determined from die concentration of petroleum resins. The aliphatic side chains of the alkylaromatic system of the asphaltenes have a small influence. The coke residue can be related to the data from structural group analysis which describe the aromatic character of the samples. 

The reaction kinetic constants activation energy E and frequency factor A, can only be correlated with the concentration of paraffinic carbon, CP (from structural group analysis) with the concentration of dispersion medium (fiom colloid analysis) and with the H/C ratio (from elemental analysis). These functions show correlation coefficients of an acceptable magnitude. Examination of the correlation of the concentration of maltenes revealed a similar tendency but with very low coefficients of correlation. It is well known that the dispersion medium contains the highest concentration of chemical bonds, which can be cracked under the chosen reaction conditions [4-20]. In the pyrolysis experiments from distillation residues, about 92 % of the dispersion medium was converted, whereas conversion of the petroleum resins was only 83 %, despite the fact that the kinetic coefficients are of nearly the same magnitude for the two components. 

Quantitative analysis by NIR of petrochemicals dates back to the 1930s. Since then a range of NIR calibrations have been developed, for example, for octane number, methyl group analysis, and methanol content in petroleum. NIR has been used to monitor water, detergent solids, and glycerol in shampoo, and to analyze moisture and lubricant levels on polymer films. Process NIR spectrometers have been used to monitor naphtha composition and NIR instrumentation has been used to monitor ethylene polymerization. 

Some of the better treatments of electronic absorption spectrophotometry are located in unobvious places. Coggeshall s Spectroscopic Functional Group Analysis in the Petroleum Industry appears in the series. Organic Analysis. We highly recommend it. 

Carbon distribution and ring content data are used in characterization of oils in the refin-ing/manufacturing process and can also correlate to critical performance properties (ASTM D3238 Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the n-d-M Method). Aromatic carbon concentration in weight percent characterizes properties and toxicity of plasticizers obtained from petroleum products. 

Coupled LC-LC can separate high-boiling petroleum residues into groups of saturates, olefins, aromatics and polar compounds. However, the lack of a suitable mass-sensitive, universal detector in LC makes quantitation difficult SFC-SFC is more suitable for this purpose. Applications of multidimensional HPLC in food analysis are dominated by off-line techniques. MDHPLC has been exploited in trace component analysis (e.g. vitamin assays), in which an adequate separation for quantitation cannot be achieved on a single column [972]. LC-LC-GC-FID was used for the selective isolation of some key components among the irradiation-induced olefinic degradation products in food, e.g. dienes and trienes [946],... 

The Oil Companies International Study Group for Conservation of Clean Air and Water, Europe (1982) Analysis of trace substances in aqueous effluents from petroleum refineries. Concawe report no 6/82... 

In summary, the terminology used for the identification of the various methods might differ. However, in general terms, group-type analysis of petroleum is often identified by the acronyms for the names PONA (paraffins, olefins, naphthenes, and aromatics), FIONA (paraffins, isoparaffins, olefins, naphthenes, and aromatics), PNA (paraffins, naphthenes, and aromatics), PINA (paraffins. 

Weisman, W. (Ed.). 1998. Analysis of Petroleum Hydrocarbons, Environmental Media Total Petroleum Hydrocarbon Criteria Working Group Series. Amherst Scientific Publishers, Amherst, MA. 

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.)... 

In connection with the analysis of the lubricant fraction of the project s representative petroleum, the striking part is that branched paraffins are not present in any measurable amount and that, except in the residue portion, purely aromatic hydrocarbons (containing aromatic rings plus appropriate paraffin side or connecting groups) are not present in any measurable amount. 

Twenty-five years ago a unit of 100 men was a very large petroleum laboratory staff. Today numerous major oil companies have over 700 men in the groups that grew from those older laboratories. The number of men engaged in analysis and testing has grown proportionately. 

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