Multi-Component Distillation


Multi-Component Distillation Column design is much more calculation intensive in comparison to binary distillation column design. Though it can be carried out by using various correlations available in the literature,  accurate design of multi-component distillation columns is only possible by performing rigorous stage-wise calculations. To ease the rigorous design calculations of multi-component distillation columns, some assumptions and few tested correlations can be used. EQ-COMP can calculate major design parameters for multi-component distillation columns using rigorous stage-wise calculations based on some widely used assumptions using few tested correlations. EQ-COMP requires following input parameters for its calculations:

  1.  Feed temperature
  2. Feed composition
  3. Column operating pressure
  4. Feed flowrate
  5. Light key and heavy key components
  6. Split of light key and heavy key components in the top product
  7. Reflux ratio as number of times minimum reflux

EQ-COMP initially calculates minimum reflux and attainable distillate composition using Underwood correlation. Further it calculates the operating reflux ratio and uses it along with other parameters to find the theoretical number of trays in the rectification and stripping section to attain the desired distillate and bottom composition. It also calculates overall column efficiency t0 find actual number of trays and column height and calculates maximum allowable vapour velocity and vapour flow rate to find column area and column diameter. EQ-COMP uses widely popular assumption of equimolar overflow while performing rigorous stage-wise calculations. A sample result for multi-component distillation column design for a hydrocarbon mixture of n-pentane, n-hexane, n-heptane and n-octane using EQ-COMP can be downloaded from the below link.


EQ-COMP can perform rigorous stage-wise calculations based on the assumption of equimolar overflow for binary hydrocarbon mixtures also. In case of binary distillation column design using EQ-COMP, the present calculation module may avoid inaccuracies arising due to graphical representation of McCabe Thiele diagram resulting in better accuracy than when widely popular McCabe Thiele diagram is used manually.

Results for multi-component distillation column calculation module can be requested by downloading the input MS excel file from the below link, filing it and sending it on


The cost of this calculation is US $ 200.  The results of this calculation module can be requested through VLE Calculator page