Polynuclear aromatic hydrocarbon , diesel

Methanol use would also reduce pubHc exposure to toxic hydrocarbons associated with gasoline and diesel fuel, including ben2ene, 1,3-butadiene, diesel particulates, and polynuclear aromatic hydrocarbons. Although pubHc formaldehyde exposures might increase from methanol use in garages and tunnels, methanol use is expected to reduce overall pubHc exposure to toxic air contaminants. 

Standardization. Standardization in analytical chemistry, in which standards are used to relate the instrument signal to compound concentration, is the critical function for determining the relative concentrations of species In a wide variety of matrices. Environmental Standard Reference Materials (SRM s) have been developed for various polynuclear aromatic hydrocarbons (PAH s). Information on SRM s can be obtained from the Office of Standard Reference Materials, National Bureau of Standards, Gaithersburg, MD 20899. Summarized in Table VII, these SRM s range from "pure compounds" in aqueous and organic solvents to "natural" matrices such as shale oil and urban and diesel particulate materials. 

According to the vendor, the technology can effectively treat almost aU hydrocarbons (inclnd-ing gasoline, crnde oil, diesel fnel, and jet fnel), pentachlorophenols, polychlorinated biphenyls, benzene, tolnene, ethyl benzene, xylene, polynuclear aromatic hydrocarbons, trichloroethylene, trichloroethane, and suspended solids. The granules can also be used to remove vegetable-based oils and fats. Another technology advantage is the ability of the SFC system to remove oil emulsified in water to concentrations less than 15 mg/hter. 

MacCrehan, W. A., W. E. May, S. D. Yang, and G. A. Benner, Jr., Determination of Nitro Polynuclear Aromatic Hydrocarbons in Air and Diesel Particulate Matter Using Liquid Chromatography with Electrochemical and Fluorescence Detection, Anal Chem., 60, 194-199 (1988). 

Schuetzle, D., and J. M. Perez, Factors Influencing the Emissions of Nitrated-Polynuclear Aromatic Hydrocarbons (Nitro-PAH) from Diesel Engines, J. Air Pollut. Control Assoc., 33, 751-755 (1983). 

Gas Chromatography-Mass Spectrometric Characterization of Polynuclear Aromatic Hydrocarbons in Particulate Diesel Emissions... 

The black material in diesel exhaust consists of small particles that are rich in polynuclear aromatic hydrocarbons. 

Rappaport, S.M. Jin, Z.L. Xu, X.B. High-performance liquid chromatography with reductive electrochemical detection of mutagenic nitro-substituted polynuclear aromatic hydrocarbons in diesel exhausts. J. Chromatogr. 1982, 240, 145-154. 

Breuer GM, 1984. Solvents and techniques for the extraction of polynuclear aromatic hydrocarbons from filter samples of diesel exhaust. Anal Lett 17 1293-1306. 

Eisenberg WC, Cunningham DLB. 1985. Analysis of polycyclic aromatic hydrocarbons in diesel emissions using high performance liquid chromatography A methods development study. In Cook M, Dennis AJ, eds. Polynuclear aromatic hydrocarbons Mechanisms, methods and metabolism. Columbus, OH Battelle Press, 379-393. 

Howard AG, Mills GA. 1983. Identification of polynuclear aromatic hydrocarbons in diesel particulate emissions. Int J Environ Anal Chem 14 43-54. 

Tan YL. 1988. Analysis of polynuclear aromatic hydrocarbons in shale oil and diesel particulates. Anal Lett 21 553-562. 

The aromatic hydrocarbon content of diesel fuel affects the cetane number and exhaust emissions. One test method (ASTM D-5186) is applicable to diesel fuel and is unaffected by fuel coloration. Aromatics concentration in the range 1-75 mass% and polynuclear aromatic hydrocarbons in the range 0.5-50 mass% can be determined by this test method. In the method, a small aliquot of the fuel sample is injected onto a packed silica adsorption column and eluted with supercritical carbon dioxide mobile phase. Mono- and polynuclear aromatics in the sample are separated from nonaromatics and detected with a flame ionization detector. The detector response to hydrocarbons is recorded throughout the analysis time. The chromatographic areas corresponding to the mononuclear aromatic constituents, polynuclear aromatic constituents, and nonaromatic constituents are determined, and the mass-percent content of each of these groups is calculated by area normalization. 

A simpler way to achieve a considerable reduction in the mass of particulates emitted, is the use of special diesel oxidation catalysts (Section 1.4). They offer advantages over filtering devices as they are simple, cost effective and can also reduce the emissions of CO, gaseous hydrocarbons, aldehydes and polynuclear aromatic hydrocarbons. Their main disadvantage is that their particulate mass reduction efficiency is only about half that achieved by filtering devices. 

Since about 1991, diesel oxidation catalysts have been generally applied to passenger cars in the European Union and to some medium and heavy duty trucks in the USA. Their principle of operation is shown in Fig. 101. The amount of carbon monoxide, hydrocarbons and aldehydes is reduced by oxidation of these components to carbon dioxide and water. The mass of particulate matter emitted is reduced by the oxidation of the liquid hydrocarbons, which are adsorbed on the particulates. These liquid hydrocarbons originate both from the fuel and the lubricating oil, and are commonly denoted as the soluble organic fraction (SOF). The adsorbed polynuclear aromatic hydrocarbons are also removed by oxidation. 

In addition to the exhaust gas components legislated for, the diesel oxidation catalyst also reduces the emissions of exhaust gas components such as aldehydes and polynuclear aromatic hydrocarbons, see Fig. Ill [70]. 

Figure 111. Emission of aldehydes, acrolein and various polynuclear aromatic hydrocarbons of two passenger cars equipped with an IDI/NA and with a DI/NA diesel engine, once without and once with a diesel oxidation catalyst, in the US-FTP 75 vehicle test cycle (monolith catalyst with 62 cells cm dedicated diesel washcoat formulation with a platinum loading of 1.76 g 1 in the fresh state vehicle dynamometer tests according to the US-FTP 75 vehicle test procedure, with passenger cars equipped with a DI/NA and with an IDI/NA diesel engine of displacement 2.0 1). Reprinted with permission from ref [70], 1990 Society of Automotive Engineers, Inc.

Schuetzle D, Lee FSC, Prater TJ (1981) The identification of polynuclear aromatic hydrocarbon (PAH) derivatives in mutagenic fractions of diesel particulate extracts. Intern JEnviron Anal Chem 9, 93-144. 

Compounds that evaporate may remain in the gas phase but can also distribute onto particles in the atmosphere. Other compounds may be released on particles such as the polynuclear aromatic hydrocarbons produced in the combustion of diesel fuel or in wood smoke. It is of interest to explore how compounds distribute between the particle and the vapor phase since this will influence their environmental behavior. Distribution onto a particle will enhance the potential for wet or dry deposition, major transport processes for moving compounds to surface water or onto vegetation. Compounds in the vapor phase will be subject to a range of photoinduced transformation processes, but how susceptible are compounds sorbed on particles ... 

Nitrated Polynuclear Aromatic Hydrocarbons During Sampling of Diesel Emissions, J. of Air Pollution Control Assoc., Submitted, 11/82. 

Salmeen, I., Pero, a., Riley, T., Hampton, C., Prater, T., Corse, R. and Schuetzle, D., "Identification and Rigorous Quantitation of Direct-Acting Ames Assay Mutagens in Diesel Particulate Extracts , to be presented at the Sixth International Symposium on Polynuclear Aromatic Hydrocarbons, Columbus, Ohio (Oct. 27-29, 1982). 

The internal combustion engine is a notorious polluter, but the diesel engine has the additional emission of particulate matter (10-25 pg/m ) which is rich in polynuclear aromatic hydrocarbons such as phenanthrene, fluoranthene, benzo(a)pyrene, and benzoperylene—all of which are carcinogenic. 

This test method covers the determination of the total amounts of monoaromatic and polynuclear aromatic hydrocarbon compounds in motor diesel fuels, aviation turbine fuels, and blend stocks by supercritical fluid chromatography (SFC). The range of aromatics concentration to which this test method is applicable is from 1 to 7S mass %. The range of polynuclear aromatic hydrocarbon concentrations to which this test method is applicable is from O.S to SO mass %. 

The United States Environmental Protection Agency (USEPA) regulates the aromatic content of diesel fuels. California Air Resources Board (CARB) regulations place limits on the total aromatics content and polynuclear aromatic hydrocarbon content of motor diesel fuel, thus requiring an appropriate analytical determination to ensure compliance with the regulations. Producers of diesel fuels will require similar determinations for process and quality control. This test method can be used to make such determinations. 

Results obtained by this test method have been shown to be statistically more precise than those obtained from Test Method D 1319 for typical diesel fuels, and this test method has a shorter analysis time. Cooperative study data has found this test method to be more precise than the published precision of Test Method D 1319 when applied to aviation turbine fuels and diesel fuels. Results from this test method for total polynuclear aromatic hydrocarbons are also expected to be at least as precise as those of Test Method D 2425. 

Reference Fuel—A fuel (motor diesel fuel, aviation turbine fuel, or blend stock) with accepted values for both mass % tot aromatics and mass % polynuclear aromatic hydrocarbons which have been established through cooperative testing in multiple laboratories. 

Polynuclear aromatics are hydrocarbons containing more than one fused benzenoid ring. These substances primarily occur in coal, coal tar, heavy oil, diesel fnel and many petroleum products. They are also found in soils, sediments, solid wastes, many wastewaters, emission from indnstrial boilers and tobacco smoke at trace concentrations. In the PAH class, U.S. EPA has hsted 16 compounds as priority pollutants in potable water and wastewater and 22 componnds in soil and solid wastes. Except naphthalene most PAH compounds have little commercial applications. However, they may be generated from various sources or industrial operations the exposure to which may pose risk to human health. Many PAHs may cause cancers, affecting a variety of tissues. However, only benzo[a]pyrene is a potent human carcinogen, while naphthalene, benzo[a]anthracene. 

Since 1975 catalysts have been fitted to vehicles to control emissions, initially of hydrocarbons and carbon monoxide (oxidation catalysts), and latterly also of oxides of nitrogen (three way catalysts). This contribution will demonstrate the ability of precious metal based catalysts not only to control carbon monoxide, hydrocarbons and nitrogen oxides but also the polynuclear aromatic fraction from both gasoline and diesel fuelled vehicles. The data will include that from both fresh and aged catalyst systems and also those exposed to leaded gasoline. 

Presently the major step in the GTL conversion is considered to be the Fischer-Tropsch synthesis of hydrocarbons from synthesis gas (CO-I-H ). The classical processes produce waxes (solid hydrocarbons) that are further upgraded into the components of liquid fuels (gasoline, diesel). Diesel production by this technology seems to be the best solution. The synthetic diesel fuel has better characteristics compared to the fuel grades produced from oil (standard EN-590) the cetane number is 75 (versus 55 for the oil-derived diesel) the content of polynuclear aromatic compounds is 0.1 (versus 6%) the sulfur content is 0 ppm (versus 50 ppm). Such synthetic fuels can be used as additives to the oil-based diesel. GTL-diesel is used in Germany, Austria, and Sweden and the blends of the synthetic fuel and conventional diesel are used in France, Italy, and other countries. 

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