Results for the A3 example simulation

The following figures show the composition, phase flow, and temperature profiles throughout the first distillation tower (T1).

Figure 4: Composition profiles in the first distillation tower

Figure 5: Vapor flow, liquid flow, and temperature profiles in the first distillation tower

With the addition of cyclohexane (CH) to the isopropyl alcohol (IPA) and water mixture, we achieve a good separation between the IPA and water. Water is concentrated at the top of the distillation tower while we achieve effectively pure IPA at the bottom of the distillation tower.

The increase in water concentration after the first distillation tower and subsequent liquid-liquid phase separation in the decanter provides us with an IPA-water stream that exceeds the azeotropic area of the vapor-liquid equilibrium. We can then separate water and IPA in the second distillation tower without complications from the azeotrope.

The following figures show the composition, phase flow, and temperature profiles throughout the second distillation tower (T2).

Figure 6: Composition profiles in the second distillation tower

Figure 7: Vapor flow, liquid flow, and temperature profiles in the second distillation tower

We find good separation between IPA and water within the second distillation tower. We achieve effectively pure water at the bottom of the tower, as required by the process specifications. The top product of the second distillation tower is close enough to the fresh feed composition that we can recycle it back to the first distillation tower as additional IPA-water feed.