Hydrocarbon type testing

Determination of hydrocarbon types in liquid penoleum products by a fluorescent indicator adsorption test (ASTM D1319)... 

Separations and Analyses. After removal of trace amounts of acids and bases from the <200° C distillates by extraction methods (16), a chromatographic separation with silica gel provided a check for the presence of olefins. No olefins were detected thus, the acid- and base-free distillates were analyzed by ASTM D2789-71, Standard Method of Test for Hydrocarbon Types in Low Olefinic Gasoline by Mass Spectrometry. The separation and analysis scheme for this distillate is shown in Figure 2. 

In this test method, a small amount of sample is introduced into a glass adsorption column packed with activated silica gel, of which a small layer contains a mixture of fluorescent dyes. When the sample has been adsorbed on the gel, alcohol is added to desorb the sample down the column and the hydrocarbon constituents are separated according to their affinities into three types (aromatics, olefins, and saturates). The fluorescent dyes also react selectively with the hydrocarbon types and make the boundary zones visible under ultraviolet light. The volume percentage of each hydrocarbon type is calculated from the length of each zone in the column. 

Other test methods are available. Content of benzene and other aromatics may be estimated by spectrophotometric analysis (ASTM D-1017) and also by gas-liquid chromatography (ASTM D-2267, ASTM D-2600, IP 262). However, two test methods based on the adsorption concept (ASTM D-2007, ASTM D-2549) are used for classifying oil samples of initial boiling point of at least 200°C (392°F) into the hydrocarbon types of polar compounds, aromatics, and saturates and recovery of representative fractions of these types. Such methods are unsuitable for the majority of naphtha samples because of volatility constraints. 

Normally, impregnated TLC plates are only used for special separations, i.e. rarely, so that commercially produced plates of this type would be too expensive. Thus, A. Koch describes the separation of plant hpids on 5 x 5 cm HPTLC sUica gel 60 plates which were impregnated with 0.5 % phosphoric acid especially for this application [27]. The six relevant polycyclic aromatic hydrocarbons are tested for rather more frequently in the monitoring of drinking water. An HPTLC precoated layer impregnated with caffeine is manufactured commercially especially for this apphcation. 

ASTM Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Techniques, ASTM D-1319-77. American Society for Testing Materials, Philadelphia, PA, 1954. 

IP391, Standard Methods for Analyzing and Testing of Petroleum Related Products, Aromatic Hydrocarbon Types in Diesel Fuels and Distillates, The Institute of Petroleum, 1997, London, UK. 

DIN 51448-1-97. Testing of liquid petroleum hydrocarbons. Determination of hydrocarbon types. Part 1 Gas chromatographic analysis by column switching procedure. 

Coal liquids consist of hundreds of individual components and therefore, it is very difficult to identify all the individual components in a sample. The components can be classified as different types such as paraffins, naph-thenics, and aromatics. Because of an MS ability to identify compound-type unique molecular ion fragment patterns, hydrocarbon-type analysis by MS has been practiced for over four decades. ASTM D-2425 specifies a standard test method for hydrocarbon types in middle distillates by MS, with a boiling range of 20 343°C. This is within the boiling range of many CTL process products, so GC-MS has been used for hydrocarbon-type analysis in coal liquids. Initial product separations are conventionally needed for GC-MS-type analysis, such as distillation (ASTM D-86), elution chromatography. 

Ramfrez V, Sanchez JA, Hernandez G, Solis S, Antano R, Manriquez J, Bustos E (2011) A promising electrochemical test for evaluating the hydrocarbon - type pollutants contained in industrial waste soils. Int J Electrochem Sci 6 1415-1437... 

Solid Oxide Fuel Cells, Direct Hydrocarbon Type, Fig. 4 Cell voltage versus time at fixed current densities from SLT-supported. (a) and NiYSZ-supported (b) SOFCs tested at 800 °C (From Ref [34])... 

The inhibition of SCR reactions by HC were studied in the laboratory flow reactor at temperatures around 200-300 °C typical of diesel vehicles over the FTP-75 drive cycle. From an analytical speciation of HC during a typical diesel cold start event, reasonable surrogates for laboratory testing were determined to be propylene (for olefins), benzene (for aromatics), and n-decane (for paraflhns). As described earlier, the initial Cu and Fe SCR catalysts contained beta zeolite. Laboratory evaluations demonstrated that co-feeding any of the three hydrocarbon types had a... 

FIGURE 13.26 Chromatogram from hydrocarbon type analysis of a test sample and a typical gasoline sample. (Reprinted from Reference 81, Journal of Chromatographic Science, Copyright 1981, Preston Pubhcations, A Division of Preston Industries, Inc.)... 

In 1948, a procedure was described by A. L. Conrad and later refined by D. W. Ciidle and R. L. LeToumeau for determining olefins, aromatics, and saturates in cracked gasoline. This procedure evolved into ASTM Test Method D1319, Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption, often abbreviated as "FIA. ... 

Cooperative studies are underway in ASTM D02.04 to find a better test method for total olefins. Cooperative work has been done to validate new gas chromatographic methods that trap the olefins on silver nitrate impregnated traps. These include a gas chromatographic multi-dimensional procedure for oxygenates and paraffin, olefin, naphthene, aromatic (O-PONA) hydrocarbon types in petroleum distillates and a GC fast total olefins analyzer (FTO) method. The FTO method has the advantage that the analysis time is quicker. The O-PONA method is an expanded version of ASTM D5443 and... 

The first level of compositional information is group-type totals. ASTM Test Method D1319, Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption, gives volume percent saturates, olefins, and aromatics in materials that boil below 315 C (600 F). This covers jet fuels but not all diesel fuels, most of which have an end point above 315°C. Despite this limitation, the method has been used widely for diesel fuel due to the lack of a suitable alternative. 

Mass spectrometry has been a powerful technique for hydrocarbon-type analysis of middle distillates. It can provide more compositional detail than chromatographic analysis. Hydrocarbon types are classified in terms of a Z-seiies. Z in the empirical formula C H2 +z is a measure of the hydrogen deficiency of the comp>ound. ASTM Test Method D2425, Hydrocarbon Types in Middle Distillates by Mass Spectrometry, determines eleven hydrocarbon types ranging from Z = -t- 2 (paraffins) to Z = —18 (tricyclic aromatics). 

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