Gasoline components

More general techniques covering a wider range employ gas chromatography (Durand et al., 1987). This enables identification and analysis of the nearly 200 gasoline components whose octane numbers are known. 

The development of catalytic converters for combustion of unburned hydrocarbons prohibits a return to lead compounds and henceforth refiners are turning to oxygenated compounds that must be used as a gasoline component therefore, in amounts much greater than those of lead compounds. 

Durand, J.P., Y. Boscher and N. Petroff (1987), Automatic gas chromatographic determination of gasoline components. Application to octane number determination . Journal of chromatography, No. 395, p. 229. 

For these reasons, ethanol is most likely to find use as a motor fuel in the form of a gasoline additive, either as ethanol or ethanol-based ethers. In these blend uses, ethanol can capture the high market value of gasoline components that provide high octane and reduced vapor pressure. 

LPG recovered from natural gas is essentially free of unsaturated hydrocarbons, such as propylene and butylenes (qv). Varying quantities of these olefins may be found in refinery production, and the concentrations are a function of the refinery s process design and operation. Much of the propylene and butylene are removed in the refinery to provide raw materials for plastic and mbber production and to produce high octane gasoline components. 

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. 

Process Stream Separations. Differences in adsorptivity between gases provides a means for separating components in industrial process gas streams. Activated carbon in fixed beds has been used to separate aromatic compounds from lighter vapors in petroleum refining process streams (105) and to recover gasoline components from natural and manufactured gas (106,107). 

Catalysts in the ZSM-5 and ZSM-11 family are used to convert methanol into high octane gasoline components in the Mobil MTG process (45). 

These non-linear equations can be embedded into the refinery s linear program (LP) to achieve compliance and optimize the gasoline blend. The key FCC gasoline components that influence RFG are ... 

Alkylation is one of the refining processes in which light olefin molecules are reacted with isobutane (in the presence of either sulfuric or hydrofluoric acid) to produce a desirable gasoline component called alkylate. 

Anti-dumping is a federal requirement to prevent refiners from blending the good gasoline components in reformulated gasoline and the bad components in conventional gasoline. 

Physical and Chemical Properties of Toxic Gasoline Components... 

There are many components of gasoline that readily dissolve in water and are transported as solutes in the groundwater. Most gasoline products are volatile and can release gas into the soil void in gaseous form, particularly in the unsaturated zone. Besides these three forms, gasoline components can be adsorbed by the soil matrix and exist in the soil as adsorbates. 

For vapor to move in the unsaturated zone, the soil formations must be sufficiently dry to permit the interconnection of air passages among the soil pores. Vapor concentration and vapor flow govern its movement. Vapor can move by diffusion from areas of higher concentration to areas of lower concentration and ultimately to the atmosphere. Therefore, the transportation of the vapor phase of gasoline components in the unsaturated zone can pose a significant health and safety threat because of inhalation and explosion potential. 

Typical values of H for gasoline components range between 20 and 500 atm (0.03 to 0.30 in dimensionless units at the standard condition [Patm = 1]). 

For effective volatilization using an enclosed mechanical aeration system, contaminated soil is mixed in a pug mill or rotary drum. The gasoline components are released from the soil matrix by the churning action of the air/soil contact. The induced airflow within the chamber captures the gasoline emissions and passes them through an air pollution control device (e.g., a water scrubber or vapor-phase carbon adsorption system) before they are discharged through a properly sized stack. 

For some of the treatment profiles, the specific components that make up the total cost were not provided in the source materials, such as for capital or operation and maintenance activities. In other cases, the types of contaminants present at the sites, other than MTBE, were not identified in the source materials. Sites may have been contaminated with gasoline components such as petroleum hydrocarbons, as well as oxygenates, and the treatment costs reported are for cleanup of both the gasoline components and oxygenates. 

Wilson, J.T., Fate and transport of MTBE and other gasoline components, in MTBE Remediation Handbook, Moyer, E.E. and Kostecki, P.T., Eds, Amherst Scientific Publishers, Amherst, MA, 2003. 

Stratco A process for making a high-octane gasoline component by alkylation of C3 - C5 hydrocarbons with isobutane, catalyzed by sulfuric acid. The product is known as an alkylate. Operated in several oil refineries in the United States. 

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