Shortcut Distillation - Main Window

Add a shortcut column to a flow sheet

Select the shortcut icon on the PFD palette
then position the mouse at the desired location on the drawing and left click. a Configuration window opens that allows adding a condenser and a reboiler to the icon display. This is for display only, and does not affect calculations.

Depending on the choices, one of four column icons may be drawn onto the PFD (no reboiler/condenser, with condenser, with reboiler, or with both reboiler and condenser).

Feeds and Products

The model supports an unlimited number of feeds and products. At least one feed and one product are required. When no condenser is configured, an overhead product should be declared. A reboiler always is optional.

Side Product Phases

Side draws default to L (liquid) phase but may be declared V (vapor). A mixed phase declaration (M) is not allowed.

Condenser Product Phases

The condenser phase defaults to V, but may be reset to M (mixed). Unlike rigorous distillation models, an overhead product consisting of both vapor and liquid phases is combined into one mixed phase total product.

Water Decant

Water may decanted only from a condenser. Any free water in the overhead, not specifically decanted with a WATER statement, is included in the overhead product; and must be accounted for in the overhead stream specification (if given).

Note: The shortcut only supports one hydrocarbon product and one water product from the condenser.

After drawing the Shortcut unit on the flow sheet, feeds and products are connected. The number of products impacts the number of Fenske sections in column. Not counting the water draw (if present) and counting the vapor and liquid from the condenser as one product, the number of sections is given by:

No. Of Sections = No. Of Products - 1

Thus, a conventional column with one overhead and one bottoms has one Fenske section. A refinery unit with three side draws (not including a possible draw off the condenser) has a total of five products and thus four sections.

Note: The column configuration impacts the Feeds and Products WINDOW, and the Specifications WINDOW. Changes in the number of products will cause side effects to these windows.

Connecting or removing streams from the shortcut object on the PFD has side effects that carry on to the Shortcut Data Entry Window.

The Shortcut Distillation Data Entry Windows

Displays the Window where you can enter data for a shortcut distillation column. The main Shortcut WINDOW is invoked either upon OK of the Shortcut Distillation Configuration WINDOW or upon Double-Click of existing Shortcut Unit on PFD. It is similar in many respects to a Column or Compressor WINDOW.

Keyword analogs to the data on the main WINDOW are found on the SHORTCUT, EVALUATE and METHOD statements.

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