Abstract

Gasoline and Other Motor Fuels. Albert M. Hochhauser (ExxonMobil Research and Engineering Co.). Gasoline and other motor fuels comprise the largest single use of energy in the U.S. The cost of this energy continues to be a primary factor in the national economy. The fraction of resources from which these fuels come that is provided by foreign sources is a matter of political concern. Rapid increases in the price of crude oil has led to programs for developing alternative sources of fuels such as biomass and natural gas. Alternative fuels are being considered for their potential to reduce greenhouse gas emissions and the desire to reduce dependence on petroleum based fuels.

All motor fuels in the U.S. are manufactured by private companies. Many participate in other aspects such as refining or marketing. Gasoline demand is determined by the numbers of cars, paved roads, population, and economic growth. Gasoline must meet exacting specifications and vary according to location, temperature and altitudes at which the product is used. Octane is probably the single most recognized measure of gasoline quality. Petroleum refining begins with distillation of crude oil into many fractions. Most gasoline in the U.S. is obtained by catalytic cracking. Reforming increases octane. Gasoline additives (eg, dyes, antioxidants, detergents, etc.) are used to improve performance. Stricter emission standards have resulted in changes in vehicle hardware. Diesel fuel, second to gasoline, is used in a wide variety of engines. The ability of diesel fuel to burn properly is described by its cetane number. Diesel manufacturers have found it difficult to meet emission standards. Alternative fuels include biomass based liquids, natural gas (either compressed or converted to liquids) and liquefied petroleum gas.