PrintContinuous Fractionation (1880-1910)
Continuous fraction with multiple stills replaced batch operations in the refineries, enabling increased throughputs and the production of multiple distillate fractions as products from a refinery [2]. As shown in Figure 11.2, a series of stills could operate continuously by taking an overhead fraction from the crude oil in the first still by flashing and moving the remaining liquid to a still drum while continuously introducing more fresh feed to the first still. The second still operates at a higher temperature to produce a higher boiling distillate. The reflux to the column with bubble trays was adjusted from the color of the overhead stream, utilizing a “look box,” shown in the diagram in Figure 11.2, to improve separation.
The demand for kerosene as a source of light declined with the invention of the electric light bulb in 1879. However, the first powered airplane flight in 1903 and mass production of an automobile (Model T) in 1908 ushered in a large demand for gasoline that cannot be met by simple distillation. Thermal cracking provided means to increase gasoline supply. This was the beginning of a new era in petroleum refining, incorporating a conversion process with separation processes.
