Dynamics mode results for the BA1 example simulation

In Process mode, the condenser operates at total reflux. The Scenario RR3 scenario switches the simulation to Dynamics mode and then runs a dynamic simulation. At the start of the dynamic simulation, the scenario switches the condenser operation to include a product draw. It sets the reflux ratio (C1.RefluxRatio) to 3, and we see methanol product accumulate in the internal tank (T1). When the purity of the distillate from the batch distillation column reaches less than 70%, the dynamic simulation stops, and the batch is complete.

The following figure shows the liquid compositions of methanol and water in both the pot and the distillate as the dynamic simulation progresses. We see that water does not reach the top of the batch distillation column until about 95 minutes have passed, at which point we see a relatively steep drop in methanol purity in the distillate.

The following figure shows the compositions of methanol and water in T1 as the methanol product accumulates. We maintain pure methanol until water reaches the top of the batch distillation column at about 95 minutes. Because we shut off the product draw when the methanol purity in the distillate drops below 70% and the drop in purity is relatively swift once water reaches the top of the batch distillation column, we see a very limited drop in the purity of the accumulated methanol product in T1.

Overall, we produce 1.57 kmol of methanol (C1.IntT.T1.MI) at 99.4% purity (C1.IntT.T1.x[MEOH]). Therefore, our process requirement (stopping the product draw once the column distillate drops to 70% methanol) meets our high-purity objective.