Composition gasoline

Relations between Gasoline Composition and Pollutant Emissions... 

Methanol is more soluble in aromatic than paraffinic hydrocarbons. Thus varying gasoline compositions can affect fuel blends. At room temperature, the solubiUty of methanol in gasoline is very limited in the presence of water. Generally, cosolvents are added to methanol—gasoline blends to enhance water tolerance. Methanol is practically insoluble in diesel fuel. 

Gasoline composition may also be regulated in Europe. A tripartite initiative is being carried out among the European Commission, the oil industry, and the automotive industry. Based on an analysis of the required improvements in air quaUty, new regulations are to be written that control vehicle emissions and fuel composition into the twenty-first century. 

Figure 9.9. Gasoline composition and research octane numbers (RON). The RON scale is set by n-heptane (RON = 0) and 2,2,4-trimethylpentane (RON = 100). The RON of a...

The reduction in the lead content of gasoline and the introduction of reformulated gasoline have been very successful in reducing automobile emissions, due to changes in gasoline composition, with further improvements in fuel quality proposed for the early decades of this new millennium. These projections are accompanied by a noticeable and measurable decrease in crude oil quality, and the reformulated gasoline will help meet environmental regulations for emissions for liquid fuels but will be subject to continuous review because of the potential for environmental impact. 

Dishart, K. T. Exhaust hydrocarbon composition. Its relation to gasoline composition. Proc. Amer. Pfetrol. Inst. 50 514-540, 1970. 

Hamming, W. J., P. P. Mader, S. W. Nicksic, J. C. Romanovsky, and L. G. Wayne. Gasoline Composition and the Control of Smog. Report of a Joint Study by Western CMl and Gas Association and Los Angeles County Air Pollution Control Db-trict. Los Angeles Air Pollution Control District, 1%1. 185 pp. 

Fig. 8.1 Liquid and vapor gasoline compositions. Reprinted with permission from Foster KL, Mackay D, Parkerton TF, Webster E, Milford L (2005) Five-stage environmental exposure assessment strategy for mixture gasoline as a case study. Environ Sci Technol 39 2711-2718. Copyright 2005 American Chemical Society...

To clarify the mechanism by which gasoline composition is changed (reduction in concentration of the paraffins and an increase in concentration of olefins and aromatics) by ZSM-5 in the dual zeolite catalyst, experiments were carried out on catalysts containing only ZSM-5 dispersed in the matrix. The catalyst containing 1 Wt.% ZSM-5 was used in order to duplicate the concentration of ZSM-5 in the dual zeolite catalyst studied earlier. Experiments with the pure matrix catalyst were used to define the contribution of ZSM-5. 

The demonstrated performance of ZSM-5 in over 35 cracking units is reviewed. The main features of ZSM-5 are its high activity and stability, favorable selectivity, metals tolerance and flexibility, particularly when used as an additive catalyst. ZSM-5 cracks and isomerizes low octane components in the naphtha produced by the faujasite cracking catalyst. As a result and olefins are produced and gasoline compositional changes occur which explain its increased research and motor octanes. A model was developed which predicts ZSM-5 performance in an FCC unit. 

The model is divided into two parts the calculation of ZSM-5 concentration required to achieve a given activity in the unit (activity maintenance) and the impact of base gasoline composition on the gasoline octane boost for ZSM-5 of a given activity. 

Table III compares the gasoline composition from three steam deactivated catalyst systems. The first contains 10% rare earth exchanged faujasite (RE FAU) in an inert silica/clay matrix at a cell size of 2.446 nm the second contains 20% of an ultra stable faujasite (Z-14 USY) at a unit cell size of 2.426 nm in inert matrix. The third contains 50% amorphous high surface area silica-alumina (70% AI2O3 30% Si02) and 50% clay the nitrogen BET surface area of this catalyst after steam deactivation is 140 m /g. All three catalysts were deactivated for 4 hrs. at 100% steam and at 816°C.

Gasoline Compositions and Yields (Fixed Fluidized Bed Reactor Tests)... 

Schuetzle, D W. O. Siegl, T. E. Jensen, M. A. Dearth, E. W. Kaiser, R. Gorse, W. Kreucher, and E. Kulik, The Relationship between Gasoline Composition and Vehicle Hydrocarbon Emissions—A Review of Current Studies and Future Research Needs, Environ. Health Perspec., 102, 3-12 (1994). 

Extensive studies describe the development of new materials, such as transition-metal nitrides and oxynitrides, as new potential catalysts for hydroprocessing operations. Studies were performed to acquire information on the effect of high levels of ZSM-5 additive on light olefins and gasoline composition in FCC.289 It was found that ZSM-5 can substantially increase propylene and butenes, and... 

Increasing Motor Octanes by Using ZSM—5 in Catalytic Cracking Riser Pilot Plant Gasoline Composition Analyses... 

In this paper we will discuss the detailed compositional analyses generated in riser pilot plant studies with and without ZSM-5. In particular, we note the relative yields of both the branched and normal paraffins and the iso and normal olefins as a function of carbon number and relate these to the increase in motor octane. Two different base catalysts were used in this study to provide a wide range in the base gasoline composition. 

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