page_title: Vacuum distillation
section_title: Industrial-scale applications
hierarchical_section_title: Vacuum distillation / Industrial-scale applications
caption_attribution_description: This is a photograph of a large-scale industrial vacuum distillation column. It is intended for use in the English Wikipedia's "Vacuum Distillation" article and anywhere else in Wikipedia that it may be useful.
context_page_description: Vacuum distillation is distillation performed under reduced pressure, which allows the purification of compounds not readily distilled at ambient pressures or simply to save time or energy. This technique separates compounds based on differences in boiling points. This technique is used when the boiling point of the desired compound is difficult to achieve or will cause the compound to decompose. A reduced pressure decreases the boiling point of compounds. The reduction in boiling point can be calculated using a temperature-pressure nomograph using the Clausius–Clapeyron relation.
context_section_description: Industrial-scale vacuum distillation has several advantages. Close boiling mixtures may require many equilibrium stages to separate the key components. One tool to reduce the number of stages needed is to utilize vacuum distillation. Vacuum distillation columns (as depicted in Figures 2 and 3) typically used in oil refineries have diameters ranging up to about 14 meters (46 feet), heights ranging up to about 50 meters (164 feet), and feed rates ranging up to about 25,400 cubic meters per day (160,000 barrels per day).
  
  Vacuum distillation can improve a separation by:
  Prevention of product degradation or polymer formation because of reduced pressure leading to lower tower bottoms temperatures,
  Reduction of product degradation or polymer formation because of reduced mean residence time especially in columns using packing rather than trays.
  Increasing capacity, yield, and purity.
  Another advantage of vacuum distillation is the reduced capital cost, at the expense of slightly more operating cost. Utilizing vacuum distillation can reduce the height and diameter, and thus the capital cost of a distillation column.
caption: Figure 3: Large-scale vacuum distillation tower at the Fawley oil refinery[7]
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