Ideal Stages - TOWR TPLS SHOR SCDS BATC
The TOWR, Tower Plus (TPLS), and Shortcut (SHOR) column uses ideal stages. The SCDS and Batch Column use default stages by default.
With ideal stage model, the condenser and reboiler are both considered an ideal stage. If you have specify six stages, a condenser, and a reboiler CHEMCAD will consider this to be reboiler + 4 ideal stages + condenser.
Packed Mass Transfer Model - SCDS BATCThe SCDS and Batch Column have the option for packed column mass transfer. When you select packed column mass transfer the number of stages becomes number of numerical integration segments. The condenser and reboiler are both a segment. The condenser and reboiler do not use the mass transfer calculations; vapor liquid equlibrium is used for the condenser and reboiler.
If you specify 52 segments, a condenser, and a reboiler with 10 meters of packing then CHEMCAD will calculate the 10 meters of packing as 50 segments, with a segment height of 0.2 meters.