Gasoline benzene content

A European Directive, 85/210/EEC, limits benzene content to 5% by volume in all gasolines regular, premium, with or without lead. This level is easily achieved, since the average value in 1993 was less than 3%. in France, for example, average benzene concentrations of 1.7% and 2.6% were reported for leaded and unleaded premium fuels, respectively, in 1993. 

Benzene is stiU used extensively as a gasoline component iu Europe and many countries do not limit the benzene content (134). Exceptions are Austria, Norway, Sweden, and Switzerland, which set the maximum at 5.0 vol % (134). Over 90% of European motor gasolines are below the 5.0 vol % limit set by these countries. It is likely that benzene content of European gasoline will be further reduced iu the future. 

FCC gasoline contains 0.5 to 1.3 vol% benzene. Since it accounts for about 35 vol% of the gasoline pool, it is important to know what affects the cat cracker gasoline benzene levels. The benzene content in the FCC gasoline can be reduced by ... 

The benzene content of FCC gasoline is typically in the range of 0.6 vol /i to 1.3 vol%. CAAA s Simple Model requires RFC to have a maximum of 1 vol% benzene. In California, the basic requirement is also 1 vol% however, if refiners are to comply with averaging provisions, the maximum is 0.8 vol%. Operationally, the benzene content of FCC gasoline can be reduced by reducing catalyst-oil contact time and catalyst-to-oil ratio. Lower reactor temperature, lower rates of hydrogen transfer, and an octane catalyst will also reduce benzene levels. 

A tank containing 1500 m3 of naphtha is to be blended with two other hydrocarbon streams to meet the specifications for gasoline. The final product must have a minimum research octane number (RON) of 95, a maximum Reid Vapor Pressure (RVP) of 0.6 bar, a maximum benzene content of 2% vol and maximum total aromatics of 25% vol. The properties and costs of the three streams are given in the Table 3.5. 

MBR [Mobil benzene reduction] A catalytic process for reducing the benzene content of gasoline. It combines features of three earlier processes benzene alkylation with tight olefins, olefin equilibration with aromatization, and selective paraffin cracking. The olefins are obtained from FCC offgas. The catalyst is a modified ZSM-5 zeolite. Developed by Mobil Research Development Corporation in 1993. 

Penex-Plus A petroleum refining process that combines the Penex process with a process for hydrogenating benzene to cyclohexane. Developed by UOP for reducing the benzene content of gasoline first offered for license in 1991. 

Blood dyscrasias have been noted in humans acutely and chronically exposed to gasoline, but these effects are most likely due to benzene, and the incidence of these findings has decreased as the benzene content in gasoline has decreased. ... 

Density 0.7 g cmJ Benzene content 1% by mass Average molecular mass of gasoline constituents 100 g mol 1. 

Consequences of Limiting Benzene Content of Motor Gasoline, CONCAWE, den Haag, the Netherlands, Dec. 1983, pp. 1-17. 

These pathways-level models have two key advantages. First, they generally provide a better basis for extrapolation than global models because of their chemical richness. Second, and perhaps trivially obvious, they are fashioned to answer new questions concerning product quality and properties. For example, as environmental issues dictate the allowable aromatics content of gasoline, it is important to have models which can specify, e.g., the benzene content. 

Gasoline is usually produced as a blend of several petroleum streams that boil in the range of naphtha. A typical gasoline might contain 50% by volume of cracked naphtha with benzene content between 0.5 wt% and 2.0 wt% and 25% by volume of catalytically reformed naphtha with benzene content between 1 wt% and 3 wt%. Estimate the cost per gallon of gasoline of reducing the final benzene content to 0.62% by volume. Compositions of other components in the naphtha streams can be found in the patent literature. 

Ikeda M, Kasahara M. 1986. n-Hexane and benzene contents in gasoline for industrial purpose. Ind. Health 24 63-66... 

An important industrial application of CD is the alkylation of benzene with ethylene or propylene to produce ethylbenzene or cumene, respectively, using acidic ion-exchange resins such as Amberlyst or zeolites operating at 130-5065 kPa and 80-500°C. Cumene is a chemical intermediate for the production of phenol, acetone, and alpha-methyl styrene, which are used to produce resins and solvents. Ethylbenzene is an intermediate for styrene, an important monomer for polymers. Alkylation of benzene could also be used to reduce the carcinogenic benzene content of gasoline. 

Another important extraction process in refining is the removal of aromatic compounds from gasolineblending stocks. This is done because the aromatics compounds have considerable value as chemical feedstocks and because environmental regulations greatly restrict the benzene content of gasoline. A number of commercial liquid-liquid extraction processes are employed in hundreds of commercial units that can accomplish this separation. 

Regarding product quality, the gasoline will be produced with a benzene content < 1%, sulfur content <0.01% and aromatics content of 35%. Diesel fuel will have a sulfur content of < 0.05% with a lower capability of < 0.025%, and a cetane index of 52. 

D.E. Seizinger, W.F. Marshall, F.W. Cox, M.W. Boyd "Vehicle Evaporative and Exliaust Emission as Influenced by Benzene Content of Gasoline",... 

GTC Technology BTX recovery, ECC gasoline Full-range reformate Effective benzene management process to allow refiners to meet the stringent benzene content in gasoline blendstock 2 2010... 

Reforming gasoline is highly aromatic. The increased hydrogen production sought for the refinery will lead to an increase in the content of aromatic compounds, for which an outlet has to be found in petrochemicals. In all cases, the benzene content must be lowered... 

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