Hydrocarbon mixture composition

In the case of kerosene and light gasoil also, density, TBP or ASTM D86 distillation curves and PINA analysis (if available) are used, and empirical correlations are derived to yield a detailed picture of hydrocarbon mixture composition. The aromatic fraction can vary greatly for the different feeds, and information, such as the H/C of the feed, is important when PINA is not available. 

Hquid—Hquid-phase spHt the compositions of these two feed streams He oa either side of the azeotrope. Therefore, column 1 produces pure A as a bottoms product and the azeotrope as distillate, whereas column 2 produces pure B as a bottoms product and the azeotrope as distillate. The two distillate streams are fed to the decanter along with the process feed to give an overall decanter composition partway between the azeotropic composition and the process feed composition according to the lever rule. This arrangement is weU suited to purifying water—hydrocarbon mixtures, such as a C —C q hydrocarbon, benzene, toluene, xylene, etc water—alcohol mixtures, such as butanol, pentanol, etc as weU as other immiscible systems. 

Cell size depends strongly on the fuel and mixture composition more reactive mixtures result in smaller cell sizes. Table 3.2 shows that a stoichiometric mixture of methane and air has an exceptionally low susceptibility to detonation compared to other hydrocarbon-air mixtures. 

K-factors for vapor-liquid equilibrium ratios are usually associated with various hydrocarbons and some common impurities as nitrogen, carbon dioxide, and hydrogen sulfide [48]. The K-factor is the equilibrium ratio of the mole fraction of a component in the vapor phase divided by the mole fraction of the same component in the liquid phase. K is generally considered a function of the mixture composition in which a specific component occurs, plus the temperature and pressure of the system at equilibrium. 

The Gas Processors Suppliers Association [79] provides a more detailed background development of the K-factors and the use of convergence pressure. Convergence pressure alone does not represent a system s composition effects in hydrocarbon mixtures, but the concept does provide a rather rapid approach for systems calculations and is used for many industrial calculations. These are not well adapted for very low temperature separation systems. 

In the Fischer-Tropsch process, carbon monoxide reacts with hydrogen in the presence of a solid catalyst, with the formation of a mixture of hydrocarbons. The composition of the product varies considerably with the catalyst and the operating conditions. The mixture may include (in addition to hydrocarbons) alcohols, aldehydes, ketones, and acids. 

The linear dependence of dioxygen consumption on the composition of a hydrocarbon mixture is observed when... 

Stelljes ME, Watkin GE. 1993. Comparison of environmental impacts posed by different hydrocarbon mixtures A need for site-specific composition analyses. In Kostecki PT, Calabrese EJ, eds. Hydrocarbon contaminated soils and groundwater, Vol. 3. Chelsea, MI Lewis Publishers, 549-569. 

Analysis for total petroleum hydrocarbons (EPA Method 418.1) provides a one-number value of the petroleum hydrocarbons in a given environmental medium. It does not, however, provide information on the composition (i.e., individual constituents) of the hydrocarbon mixture. The amount of hydrocarbon contaminants measured by this method depends on the ability of the solvent used to extract the hydrocarbon from the environmental media and the absorption of infrared light (infrared spectroscopy) by the hydrocarbons in the solvent extract. The method is not specific to hydrocarbons and does not always indicate petroleum contamination, since humic acid, a nonpetroleum material and a constituents of many soils, can be detected by this method. 

Rather than quantifying a complex total petroleum hydrocarbon mixture as a single number, petroleum hydrocarbon fraction methods break the mixture into discrete hydrocarbon fractions, thus providing data that can be used in a risk assessment and in characterizing product type and compositional changes such as may occur during weathering (oxidation). The fractionation methods can be used to measure both volatile and extractable hydrocarbons. 

The method of analysis often used for the total petrolenm hydrocarbons (EPA 418.1) method provides a one-number valne of the total petroleum hydrocarbons in an environmental medium. It does not, by any stretch of the imagination, provide information on the composition (i.e., individual constituents of the hydrocarbon mixture). 

Five binary-hydrocarbon mixtures of ethane or ethylene with heavier hydrocarbons were studied (Table III). The only substrate used in these studies was water. If an RPT did not occur, ice always formed rapidly. When n-butane or n-pentane was the heavier component, RPTs were 100% reproducible over a particular composition range. This was not, however, true if the heavier component were propane. 

Physical chemistry and related sciences have played an increasingly important role in the explanation and prediction of physical phenomena which are useful in the production and processing of petroleum. Knowledge of the volumetric and phase behavior of hydrocarbons has so developed that such properties may be predicted with reasonable accuracy at most of the states of interest except those near retrograde dew point. The inability to describe with certainty the composition of many hydrocarbon mixtures in terms of their components places a severe limitation on the prediction of the volumetric and phase behavior of petroleum and of mixtures of its components. 

The first suggestions concerning the mechanism of catalytic reforming were based on studies with hydrocarbon mixtures that permitted only observation of composition changes.91,98,120 It was observed, for example, that about 30% of the Ci—C4 product consisted of methane and ethane. These, however, are not common products in catalytic cracking processes. In fact, when n-heptane was hydrocracked, less methane and ethane were formed than expected, according to the stoichiometry of Eqs. (2.15) and (2.16). Therefore, C5 and C6 hydrocarbons were not considered... 

Separator calculations are performed to determine the optimum operating pressure for processing a particular hydrocarbon mixture. Normally for a black oil, the composition of the produced gases, the gravity of the stock-tank oil, the producing gas-oil ratio, and the formation volume factor of the oil are calculated. Other physical properties can be calculated from the compositions of the gases or liquids. 

Figure 15.14. Breakthrough curves in the adsorption of a mixture of hydrocarbons with composition n-butane 0.4 mol %, n-pentane 25.9, w-hexane 23.9 iso and cyclic hydrocarbons 49.8 mol % (Lee, in Recent Advances in Separation Science, CRC Press, Boca Raton, FL, 1972, Vol. II, pp. 75-110).

The use of physical constants is, however, limited in the case of more complicated chemical processes the more complex the chemical change, the larger the number of physical properties necessary to investigate completely the chemical transformations. This especially holds when catalysts are involved in the reactions. When studying catalytic reactions we are dealing with catalysts as mixtures of a far more complicated nature than is the case, for example, in the structural analysis of hydrocarbon mixtures. The latter can be described, as was shown in the preceding sections, by means of a limited number of physical constants, from which either the chemical composition of the mixture or a series of other physical constants can easily be derived. For the characterization of catalysts completely different principles have to be applied even in simple cases, because in the case of a catalyst it is not chiefly its chemical composition that is important, but its chemical activity, which determines the result obtained by its chemical action. 

The diagram schematic is the same for simple hydrate systems of si (CH4 + H2O) and sll (N2 + H2O) as well as those of fixed natural gas mixture compositions, without a liquid hydrocarbon phase. Systems containing a liquid hydrocarbon are similar in behavior to the C3H8 + H2O diagram, discussed in Section 4.1.2. 

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