Simulation of a Steady-State Ternary Distillation Column

reflux ratio

4

reboil ratio

4

composition profile

temperature profile

comparison with HYSYS

Consider a steady-state ternary mixture of benzene (

23.33%mole

), toluene (

33.33%mole

), and

p

-xylene (

43.34%mole

) at

101.325kPa

. This mixture, with a thermal quality equal to 1.0 (i.e. saturated liquid), is fed to a 19-stage column with a total condenser and partial reboiler. The feed is at stage 10. The feed flow rate is set to

1kmol/hr

. You can set the values of the reflux and reboil ratios (

R

and

s

, respectively). This Demonstration computes the temperature and composition profiles using a rigorous approach, which includes both the energy and mass balances. The blue, magenta, and brown curves, shown in the composition profile, correspond to benzene, toluene, and

p

-xylene compositions, respectively. For

R=4

and

s=4

, the results found in the present Demonstration show good agreement with those given by HYSYS (http://www.aspentech.com/hysys/). HYSYS data is shown with colored dots. The calculation of enthalpies can be improved by taking temperature-dependent heat capacity, for example.