Automotive Fuels at Low Temperatures

Problems with fuels at extremely low temperatures are largely due to wax formation, increased viscosity, decreased volatility and contamination by water. This is especially true of diesel fuels, but even gasoline suffers from these problems to some extent. Some difficulties may begin to appear at temperatures above 0 deg. C. The majority of fuels are derived from petroleum crude oil. In addition, secondary processing of the crude procedures further fuel stocks from other fractions that could not otherwise be used as fuel. Cracking reduces large molecules from light gases or from the lighter products of the cracking process polymerization is similar to alkylation but results in products with a lower octane rating reforming catalytically alters certain low- octane substances, resulting in a high-octane product. The four basic molecular structures in petroleum oil products are aromatics, naphthenes, olefins and paraffins.