Chevron U.s.a. Inc.

Chevron Research Company

William R Scott

Lewis M Gibbs

Scott R Brundage

Joseph S Welstand

Michael J Fuchs

John Freel

Gregory Hemighaus

Richard J Runge

Gary S Gassaway

Fred E Barnes

Provided is an unleaded gasoline fuel which is substantially free of oxygenates, and most preferably contains substantially zero oxygenates. The gasoline fuel also has a Reid vapor pressure less then 7.5 psi, a sulfur content less than 30 ppmw, an aromatic hydrocarbon content between 25 and 30 volume percent, and/or a 50% D-86 Distillation Temperature between 210 and 220&#xb0; F., and/or a 90% D-86 Distillation Temperature between 300 and 330&#xb0; F., and the fuel composition fails the California Predictive Model requirements for emissions. Preferably, the olefin content of the fuel is also 8 volume percent or less. Such a gasoline fuel offers a substantially oxygenate free gasoline which avoids the environmental impact of oxygenates, yet when combusted in an internal combustion automobile provides good performance and good emissions, despite failing the California Predictive Model. The gasoline fuel in particular can provide surprisingly lower NOemissions than that predicted by the California Predictive Model.

Low emission, non-oxygenated fuel composition

An aviation gasoline (Avgas) fuel composition possessing a high motor octane number and which contains reduced amounts of tetraethyl lead is disclosed. The Avegas composition preferably comprises about 20 to about 80 vol % iso-octane, about 5 to about 18 vol % toluene, about 1 to about 20 vol % C to C paraffins, about 0 to about 1 ml/gallon tetraethyl lead (TEL) and the balance light alkylate. The Avgas composition may be economically produced utilizing spare methyl tertiary butyl ether plant capacity to produce iso-octane as one component of the composition.

Aviation gasoline containing reduced amounts of tetraethyl lead

Provided is a method for blending an unleaded summer gasoline containing ethanol. The method comprises providing a substantially oxygenate free unleaded gasoline blend stock having an RVP of no greater than 7.0, and preferably no greater than 6.0, and then adding sufficient ethanol to the gasoline blend stock such that the ethanol addition does not cause the T50 value to drop below the ASTM D 4814 minimum requirements of 170&deg; F.

Blending of summer gasoline containing ethanol

Provided is a method for blending an unleaded summer gasoline containing ethanol. The method comprises providing a substantially oxygenate free unleaded gasoline blend stock having an RVP of no greater than 7.0, and preferably no greater than 6.0, and then adding sufficient ethanol to the gasoline blend stock such that the ethanol addition does not cause the value to drop below the ASTM D 4814 minimum requirements of 170&deg; F.

Provided is an unleaded gasoline fuel which is substantially free of oxygenates, i.e., the fuel contains less than 1.0 weight percent oxygen based on the total weight of the fuel composition, and most preferably contains no oxygen containing compounds. The gasoline fuel of the present invention also has a Reid vapor pressure of less than 7.5 psi, a sulfur content of less than 30 ppmw, and more preferably less than 20 ppmw sulfur, and an aromatic hydrocarbon content greater than 30 volume percent and/or a 50% D-86 Distillation Point greater than 220&deg; F. and/or a 90% D-86 Distillation Point greater than 330&deg; F. The gasoline fuel preferably also has an olefin content of no greater than 8 volume percent, and more preferably 5 volume percent or less. It has been found that such a gasoline fuel offers a substantially oxygenate free gasoline which avoids the environmental impact of oxygenates, yet when combusted in an internal combustion automobile provides good performance and good emissions.

Provided is an unleaded gasoline fuel which is substantially free of oxygenates, i.e., the fuel contains less than 1.0 weight percent oxygen based on the total weight of the fuel composition, and most preferably contains no oxygen containing compounds. The gasoline fuel of the present invention also has a Reid vapor pressure of less than 7.5 psi, a sulfur content of less than 30 ppmw, and more preferably less than 20 ppmw sulfur, and an aromatic hydrocarbon content greater than 30 volume percent and/or a 50% D-86 Distillation Point greater than 220.degree. F. and/or a 90% D-86 Distillation Point greater than 330.degree. F. The gasoline fuel preferably also has an olefin content of no greater than 8 volume percent, and more preferably 5 volume percent or less. It has been found that such a gasoline fuel offers a substantially oxygenate free gasoline which avoids the environmental impact of oxygenates, yet when combusted in an internal combustion automobile provides good performance and good emissions.

The present invention provides for the accurate mapping of shallow crustal earth formations by means for refractive seismic waves to identify structure, elastic parameters and lithology of the strata undergoing survey to indicate deposits of ore, marker rock, economic minerals and the like. After a 'roll-along' technique has been used in the field to collect the refraction data and preliminary processing steps undertaken in which there are provisions for (i) accurate separation and determination of seismic shear and compressional responses; (ii) stacking displays that allow for accurate identification of shape of the surveyed strata; and (iii) final depth displays of the refracting bed segments associated with seismic shear and compressional wave velocities as well as Poisson's ratios, in accordance with the present invention, additional processing then occurs. The added processing indicates lithology of the earth formation to a surprising degree based, inter alia, on multi-dimensional space searching techniques.

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El Cerrito, CA, United States of America

William R Scott