Gasoline aromatic content

Today, NIR analyzers are being used in the refineries to determine many different properties in addition to the octane numbers of gasoline. One refinery is measuring 25 properties of their gasoline every 45 seconds. Once the spectrum has been acquired, it just takes some calculations on the attached computer to determine additional analytical properties, such as boiling points, olefin content of the gasoline, aromatic content, methyl... 

Stichting Concawe, Effect of gasoline aromatic content on polynuclear aromatic exhaust emission 1974, Report No. 6/74, September,. Stichting Concawe the Hague, pp. 1-63. 

Effect of Increasing Gasoline Aromatic Content on BaP Emitted... 

Figure 4, Relation of BaP Emissions to Gasoline Aromatic Content...

Concawe Rep. 3/73 Effect of Gasoline Aromatics Content on Exhaust Emissions, Den Haag 1973... 

Around 2000, the regulations should become more severe. In this area, a European limit of benzene of 3% appears very probable certain countries such as Germany are even looking at 1%. In Italy, it was decided towards the end of 1991, to limit benzene to 2.5% for leaded and unleaded fuels in the seven largest cities characterized by having heavy atmospheric pollution concurrently, in these same cities, the overall aromatic contents of gasolines should not exceed 33%. 

Debutanized gasoline cuts from Arabian Light crude. Reid Vapor Pressure as a function of yield, weight %. Aromatics content as a function of yield, volume %. 

The picture we see now is that of new lead-free fuels having lower aromatics content but containing a variety of oxygenates. It is thus likely that the additives entering into the composition of gasoline will be also modified. 

Aromatics Content. Aromatic compounds have very poor ignition quahty and, although they are not specifically limited in ASTM D975, there are practical limitations to using high aromatic levels in highway diesel fuel. In the United States, where gasoline demand represents about one-half of the... 

All lation. The combination of olefins with paraffins to form higher isoparaffins is termed alkylation (qv). Alkylate is a desirable blendstock because it has a relatively high octane number and serves to dilute the total aromatics content. Reduction of the olefins ia gasoline blendstocks by alkylation also reduces tail pipe emissions. In refinery practice, butylenes are routinely alkylated by reaction with isobutane to produce isobutane—octane (26). In some plants, propylene and/or pentylenes (amylenes) are also alkylated (27). 

A fuel closely related to gasoline is naphtha, which is also a potential fuel cell fuel. Naphtha is already produced in large quantities at refineries and is a cheaper fuel than gasoline, which must have octaneboosting additives blended into it. Unlike methanol, naphtha can be distributed in the same pipelines as gasoline. From the fuel cell s perspective, it has a higher H C ratio and lower sulfur and aromatics content than gasoline. 

The main use of naphtha in the petroleum industry is in gasoline production. Light naphtha is normally blended with reformed gasoline (from catalytic reforming units) to increase its volatility and to reduce the aromatic content of the product gasoline. 

Figure 10-4. Aromatic content of gasoline versus its end point.

Avaro [Aviation aromatics] A process for increasing the aromatics content of gasoline by thermal reforming in the presence of low molecular weight hydrocarbons. Used at the Shell refinery in Curacao during World War II. 

Aromatics are typically included in gasolines to increase octane number. However, high aromatic content increases engine-out hydrocarbons and NOx emissions.16 Moreover, aromatics are the main precursors of exhaust benzene, a known carcinogenic, via dealkylation of substituted aromatics.17 Therefore, reduction of total aromatic content, together with olefin content, is an important part of California phase III reformulated gasoline specifications,18 with respect to the current allowed concentrations of benzene and total aromatics of 0.8 and 25 percent of volume, respectively. 

Irrespective of the fuel supply chain, alternative fuels have generally lower tailpipe emissions in terms of local pollutants (such as NO, CO, S02, VOC and particle emissions) than conventional gasoline and diesel engines for instance, natural gas completely eliminates particle emissions synfuels are manufactured with very low sulphur and aromatic contents alcohol-based fuels have high octane numbers, which... 

Chapter 18 - The determination region of solubility of methanol with gasoline of high aromatic content was investigated experimentally at temperature of 288.2 K. A type 1 liquid-liquid phase diagram was obtained for this ternary system. These results were correlated simultaneously by the UNIQUAC model. By application of this model and the experimental data the values of the interaction parameters between each pair of components in the system were determined. This revealed that the root mean square deviation (RMSD) between the observed and calculated mole percents was 3.57% for methylcyclohexane + methanol + ethylbenzene. The mutual solubility of methylcyclohexane and ethylbenzene was also demostrated by the addition of methanol at 288.2 K. 

Determination of aromatic content of olefin-free gasoline by silica gel adsorption (ASTM D936)... 

Gasoline varies widely in composition, and even those with the same octane number may be quite different. The variation in aromatics content as well as the variation in the content of normal paraffins, branched paraffins, cyclopentane derivatives, and cyclohexane derivatives all involve characteristics of any one individual crude oil and influence the octane number of a gasoline. 

Heuss, J. M., G. T. Nebel, and B. A. D Alieva. Effects of gasoline aromatic and lead content on exhaust hydrocarbon reactivity. Environ. Sci. Technol. 8 641-647,... 

Uses. Gasoline additive, especially to aviation and premium grades with high aromatic content... 

The PONA results at constant conversion (72 vol%) in the series from EKZ4 to BETA 500 show gasoline olefin content increased from 8.6 percent to 16.4 percent, paraffin content decreased from 54.7 percent to 46.8 percent, and naphthene and aromatics contents remained constant. Research octane increased 4.2 numbers while motor octane increased 1.2 numbers. The aromatics content of the LCO as measured by the aniline point decreased with the aniline point increasing from 42 to 62. LCO yield increased from 16.0 volume percent to 18.0 volume percent, while the coke yield decreased dramatically from 4.2 percent to 2.4 percent. 

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