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Unified Supply Chain Assay

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Configure the number of distillation units

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  • Last UpdatedAug 14, 2026
  • 3 minute read

A distillation unit represents a distillation step in a refinery or laboratory. Click the New Distillation Unit button Icon New Distillation Unit. Shows a distillation unit with a green circle with a white plus in it to create a new unit in the flowsheet.

Distillation Unit details. A distillation unit needs a unique name, feed, pressure, stream names, cut points and fractionation indices

You can then add new outputs by clicking the add output Icon Add New Output. Shows two white rectangles and a blue rectangle with a black plus on it button. The new output is created above the selected one. If you need to delete an output, select it and click the delete output button Icon Delete output. Shows three rectangles white, blue, white with a red X next to the blue one.

A distillation unit requires the following:

  • A name used to refer to the distillation unit.

  • A pressure used to calculate the true boiling point of the distillation unit's products. It is only possible to enter a single bulk value for the distillation unit pressure: pressure drop over a distillation column is not modelled by the flowsheet.

  • An input source, either whole crude or the product of another flowsheet unit.

  • The feed stream of the input source connected to this distillation unit. Not available if the input source is Crude Feed.

  • Names for the distillation unit's product streams.

  • Cut points for each of the distillation unit's product streams.

  • Stripping and rectifying fractionation indices used to describe the efficiency of each stage of the distillation unit's separation.

Product names, cut points and fractionation indices can be entered directly on the Flowsheet page in the relevant text boxes for the distillation unit. Each flowsheet also has an associated separation model which can be chosen from the drop-down menu.

Whole crude is used as the feed source for the first distillation unit. Whole crude can only be used as a source for a single distillation unit within the flowsheet. Any other distillation units are fed by the product of another flowsheet unit. For example, a flowsheet may contain two distillation units representing an atmospheric and a vacuum distillation. Whole crude is used a feed for the first atmospheric distillation unit. The second distillation unit must be fed by a product of the first separation, in this case the atmospheric residue remaining after the first distillation.

Remove any distillation units that are not needed by clicking the remove distillation unit icon Icon Remove distillation unit. Shows a white page with a corner turned down and a red no entry sign (red circle with a white slot across the middle) icon in the toolbar.