The atmospheric and vacuum crude distillation units

Abstract

The distilling of petroleum products from crude oil to some extent or other has long been practiced. Certainly the ancient Egyptians, Greeks, and Romans had some form of extracting a flammable oil from, probably, weathered crude oil seepage. It wasn’t though until the turn of the nineteenth and twentieth century that crude oil well drilling was first discovered and commercialized. Originally the crude oil was refined to produce essentially kerosene (lamp oil), and a form of gasoline known then as Benzine (as opposed to Benzene already being produced from coal) and the residue used as pitch for calkin and sealing. The lamp oil or kerosene was produced to provide a means of illumination, later a lighter cut known as naphtha was produced for the same purpose but used in special pressurized lamps. The production of these early distillates was made by cascading the crude oil through successive stills each operating at successively higher temperatures. This is shown in the following diagram Figure 3.1. The crude enters the first still to be heated to a temperature that vaporizes the light components. The residue from this still enters the second one and heated to a higher temperature to vaporize the Benzine fraction. The residue enters the third still and heated to remove the Kerosene fraction. The residue from this still is a very light fuel oil which may be further heated and partially vaporized to give a pitch of sorts as a residue and a distillate which could be used as fuel. This distillate would later become the Diesel or Gas Oil fraction and used in the developing diesel engine.