Petroleum chemical composition

The powders of zeolites of various trademarks are used to produce petroleum-refining catalysts. In this connection, it is very important to have complete information concerning not only chemical composition and distribution of impurity elements, but also shape, surface, stmcture and sizes of particles. It allows a more detailed analysis of the physical-chemical characteristics of catalysts, affecting their activity at different stages of technological process. One prospective for solving these tasks is X-ray microanalysis with an electron probe (EPMA). 

The element specificity of atomic absorption spectrometry has also been used in conjunction with gas chromatography to separate and determine organo-metallic compounds of similar chemical composition, e.g. alkyl leads in petroleum here lead is determined by AAS for each compound as it passes from the gas chromatograph.75... 

Indeed, petroleum reservoirs have been found in vastly different parts of the world and their chemical composition varies greatly. Consequently, no single petroleum composition can be defined. Thus, petroleum-derived inputs to the environment vary considerably in composition, and the complexity of petroleum composition is matched by the range of properties of the components and the physical, chemical, and biochemical processes that contribute to the distributive pathways and determine the fate of the inputs. 

In addition, a method of petroleum classification based on other properties as well as the density of selective fractions has been developed. The method consists of a preliminary examination of the aromatic content of the fraction boiling up to 145°C (295°F), as well as that of the asphaltene content, followed by a more detailed examination of the chemical composition of the naphtha (bp < 200°C < 390°F). For this examination a graph is nsed that is a composite of cnrves expressing the relation among the percentage distillate from the naphtha. 

The chemical composition of petroleum also varies over a wide range. A broad functional definition of petroleum hydrocarbons is that hydrocarbons are composed primarily of many organic compounds of natural origin and low water solubility. 

Petroleum is typically described in terms of its physical properties (such as density and pour point) and chemical composition (such as percent composition of various petroleum hydrocarbons, asphaltenes, and sulfur). Although very complex in makeup, crude can be broken down into four basic classes of petroleum hydrocarbons. Each class is distinguished on the basis of molecular composition. In addition, properties important for characterizing the behavior of petroleum and petroleum products when spilled into waterways or onto land and/or released into the air include flash point, density (read specific gravity and/or API gravity), viscosity, emulsion formation in waterways, and adhesion to soil. 

Most investigations involving petrolenm hydrocarbons are regulated by various agencies that may require methodologies, action levels, and cleanup criteria that are different. Indeed, the complex chemical composition of petroleum and petroleum products can make it extremely difficult to select the most appropriate analytical test methods for evaluating environmental samples and to interpret and use the data accurately. 

As already noted, the chemical composition of petroleum and petroleum products is complex and may change over time following release into the environment. These factors make it essential that the most appropriate analytical methods are selected from a comprehensive hst of methods and techniques that are used for the analysis of environmental samples (Dean, 1998 Miller, 2000 Budde, 2001 Sunahara et al., 2002 Nelson, 2003 Smith and Cresset, 2003). But once a method is selected, it may not be the ultimate answer to solving the problem of identification and, hence, behavior (Patnaik, 2004). There are a significant number of petroleum hydrocarbon-affected sites, and evaluation and remediation of these sites may be difficult because of the complexity of the issues (analytical, scientific, and regulatory not to mention economic) regarding water and soil affected. 

Changes in the chemical composition of the kerosene during volatilization also affect the physical properties of this petroleum product. Table 16.8 summarizes the effect of volatilization on kerosene viscosity, surface tension, and density when 20%, 40%, and 60% of the initial amount has been removed by the partial transfer of light hydrocarbon fractions to the atmosphere. Only the liquid viscosity is affected, with volatilization having a negligible effect on the density and surface tension of the kerosene. 

Fuel oils are petroleum products that are used in many types of engines, lamps, heaters, furnaces, stoves, and as solvents. Fuel oils come from crude petroleum and are refined to meet specifications for each use. Fuel oils are mixtures of aliphatic (open chain and cyclic compounds that are similar to open chain compounds) and aromatic (benzene and compounds similar to benzene) petroleum hydrocarbons. In addition, they may contain small amounts of nitrogen, sulfur, and other elements as additives. The exact chemical composition (i.e., precise percentage of each constituent) of each of the fuel oils discussed in this profile may vary... 

The chemical composition of vapors and fumes from asphalt products is variable and depends on the crude petroleum source, type of asphalt, temperature, and extent of mixing. Therefore, the adverse effects from asphalt may also vary considerably depending on the source of exposure. 

Chemical Composition and Properties of Fuels for Jet Propulsion , Pergamon Press, NY(1962) 7) ASTM Standards for Ash from Petroleum Pro-... 

The early development and present status of petroleum oils as insecticides for use on deciduous fruit trees are reviewed. The biological groups of insects most susceptible to oil sprays are listed. Factors affecting oil deposit are discussed and data are cited to establish relationships between oil deposit and control. The relationship between chemical composition and control efficiency is also discussed. The possible modes of action by which petroleum oils kill insects are considered. Specifications are given for improved dormant spray oil. Current recommendations ifor the use of oil sprays in control of fruit pests occurring in New York State are listed. The possibility of developing more effective hydrocarbon insecticides is discussed. 

Chapman, Pearce, and Avens (4, 20) investigated the relation between chemical composition and insecticidal efficiency of various dormant and foliage spray oils against several common insect pests of deciduous trees, and found it to be positive. They concluded that an oil which is highly paraffinic in character is the most desirable type. Saturated narrow-cut petroleum fractions were used by Pearce, Chapman, and Frear 21) in a study of the influence of molecular weight and structural constitution on the insecticidal efficiency of such oils to eggs of the oriental fruit moth, Grapholitha molesta (Busck). Correlations between efficiency and various properties were compared on the basis of composition. The value of paraffinicity was illustrated, and the importance of other properties was indicated. 

Quality control standards have been developed for the new petroleum weed killers and laboratory techniques have been worked out tor testing and establishing the suitability of a given petroleum fraction for a specific herbicidal use. Although attempts to correlate herbicidal action with physical and chemical tests have not been entirely successful, the use of additional specific t ts to determine the chemical composition of the fraction has served as an indicator of toxicity in the specific composition under study. 

Effect of Petroleum Fuel Properties. Three primary requirements must be met by practical fuels for aircraft turbojets. These requirements are They must be available in large quantities at low cost, they must produce satisfactory performance in all types of engines, and they must be suitable for aircraft fuel systems. Petroleum fuels vary in volatility, chemical composition, and concentrations of minor nonhydrocarbon compo-... 

GEOCHEMISTRY. The study of the chemical composition of the earth in terms of the physicochemical and geological processes and principles thai produce and modify minerals and rocks. Of practical importance in discovering and establishing the limits of ore deposils, petroleum, lar sands, salt, sulfur, and other valuable resources,... 

Petroleum oils vary considerably ill composition, even when closely associated geographically. In some areas of the United States, for example, crude oils near the surface may have quite a different chemical composition from those found in deeper strata. Depth alone, however, does not correlate significantly with composition. 

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