This window is used to supply the input data for a distillation or liquid-liquid extraction column.
Pressure Profile Button
The pressure must be defined for all stages in a column. Several options for supplying the tray pressures are provided in the Column Pressure Profile Window.
Columns may have multiple feeds, with a feed or feeds introduced on any tray. A distillation column feed may be placed directly on a tray or it may be phase separated, as described in the Feed Flash Convention Window. All columns must have at least two products, an overhead product leaving tray one and a bottom product leaving the highest numbered tray. Optionally, a column may also have side draw products from any tray. It is also possible to produce Column Pseudoproducts, corresponding to tray liquids, tray vapors, thermosiphon reboiler streams and pumparounds. See the Column Feeds and Products Window for further details.
The Column Convergence Data Window is used to supply tuning factors for the calculations and to modify the column convergence criteria. For most problems it is not necessary to change the default values supplied in this window. Options for printing the Column Convergence History are also provided.
The Column Thermodynamic Systems Window is used to specify the system used for the column calculations. Different thermodynamic systems may be used for individual sections of the column.
This button provides access to the distillation column reboiler options as described in the Column Reboiler Window. Reboilers may be either kettle (the default) or thermosiphon with or without baffles.
Several distillation column condenser options, including partial, liquid and subcooled, are provided as described in the Column Condenser Window. Partial condensers may have either a vapor product or both liquid and vapor products. For the latter case the liquid product is defined as a liquid side draw product from tray one.
Any tray may have a heat source or sink as described in the Column Side Heaters/Coolers Window.
All column solution algorithms are iterative in nature, starting from an initial estimate of the column temperature and flow profiles. Initial estimates may be provided as described in the Column Initial Estimates Window, with user-supplied initial values and/or PRO/II supplying initial values via estimation techniques.
Distillation column pumparound streams may be used to move either liquid or vapor from one tray to another tray, either higher or lower in the column. There is usually a heat source or sink associated with the pumparound, either adding or removing heat from the column. See Column Pumparounds for more details.
Performance specifications may be used to set the levels for the following column operating variables: feed rates, product draw rates and heat duties. Specifications may correspond to column product streams such as rates, compositions, properties, etc., or to column operating conditions such as tray temperatures, tray flows and heat duties. Specifications are described in the Generalized Performance Specifications. A column operating variable to be calculated must be provided for each specification. See Column Specifications and Variables for more details.
Hydraulics/Packing Button
This feature may be used to supply tray and packing details for performance calculations. For existing distillation columns the trays or packings may be rated at the calculated loadings; for new columns the diameter may be determined for a specified percent of flooding. Use of this feature is described in the Column Tray and Packing Hydraulics Window.
All distillation calculations are performed for theoretical trays (perfect vapor/liquid equilibrium stages). Tray efficiencies may be used to modify the calculated results for theoretical trays and are supplied as described in the Column Tray Efficiency Window. Tray efficiencies may correspond to all components on a given tray or only to specific components as described in the Component Tray Efficiency Window.
The value entered in the Number of Trays is the number of theoretical trays in the column model (including one tray each for a condenser and reboiler).
This entry is used to limit the number of iterative solutions to be calculated before a convergence failure is signaled. See Number of Iterations for more details.
See the Column Algorithms for further details on the solution algorithms.
Most column calculations are for vapor/liquid phases. Some of the column algorithms may also be used for vapor/liquid/liquid, vapor/liquid/water and liquid/liquid calculations. See Calculated Phases for more details.
Click on this button to open the Insert/Remove trays window where you can Insert trays at required location or remove selected trays in the column.
Column should have at least three trays for this button to be enabled.
If you have selected the Chemical or Liquid-Liquid option for the Column Algorithm, you may define reactions which occur in the column on the Column Reaction Selection Window.
You may activate this button to choose the level of printed detail provided in the answer. The Column Report Options Window describes the various print and plot options available.
Alternatively, instead of entering numeric values for many input parameters, the values may be referenced using the Define system relative to any available unit operation or stream parameter calculated elsewhere in the simulation. See Column Parameters Available for Cross Referencing for more details.
Complete technical details may be found in topics under Distillation and Liquid-liquid Extraction Columns in the PRO/II Reference Manual.
Distillation Column Unit Operation - Technical Information
Liquid-Liquid Extraction Column Unit Operation - Technical Information