Raw crude oil is a broad mixture of hydrocarbons ranging from methane to heavy asphalt. In this raw state, it is only suitable for burning in larger boilers and industrial furnaces. But upgrading its value in a petroleum refinery produces: gasoline, both regular unleaded and premium grades, kerosene or jet fuel, heating oil or diesel, lube oils, greases, waxes, asphalt, specialty chemicals and petroleum coke. If you exclude agriculture, no organic industry is more important to modern technical civilization than the petroleum and petrochemical industries.

There are basically two means to make products in a petroleum refinery. One is simple fractionation to separate constituents. The second is catalytic reaction to take apart organic molecules and put them back together in more preferred arrangements. The petroleum industry responds to consumer demands for more than just clean fuels- producing consumer chemicals such as carbon black for the manufacture of tires, ammonia for fertilizers, ethyl alcohol and glycol for antifreeze, synthetic rubber for tires and gloves, and man-made fibers for clothing and plastics.

The petroleum industry has grown rapidly from the first skimming of oil seepages by the Indians for medical use and the first oil well drilled by Colonel Drake in 1859 at Titusville, Pennsylvania. The first product to propel the petroleum industry was kerosene which was used to replace whale oil in illumination. But the greatest driving force for growth has been the consumption of gasoline by the internal combustion engine begun in the early part of the twentieth century.

Today our refineries produce several grades of gasoline, low sulfur diesel, jet fuel, specialty chemicals such as benzene, toluene, aromatic solvents, many grades of asphalts for road construction, propane and butanes sold as LPG, propylene, and sulfur used for chemical uses.

The petroleum industry is large employer of chemical, mechanical, electrical and instrumentation engineers. They are active in designing, operation, development of new catalysts and chemicals, sales and executive functions. This has occurred since refining has become a complicated procedure involving numerous unit operations and chemical conversions. This industry has become so interrelated and so technical in all parts of a company that it requires the services of trained engineers.