Process mode for the CC25 example simulation

The objective of Process mode is to provide an overall mass and energy balance for the process and to estimate the product flowrates and compositions. We switch the following process specifications to meet the design requirements:

• For each heat exchanger, we switch the duty and utility flowrate specifications with the outlet stream temperature (Tto or Tso) or vapor fraction (VFto or VFso) specifications. This allows us to calculate the required utility flowrates.

• In the DME column (T1), we switch the specifications for the reflux ratio (OutRatio[T1Reflux] in SP1) and the molar composition of the DME product. We specify the DME concentration in the overhead product as 99.5 wt%.

• In the methanol dryer column (T2), we switch specifications for the reflux ratio (OutRatio[T2Reflux] in SP2) and the molar composition of the methanol recycle stream. We specify the methanol concentration in the recycle stream as 99 mol%.

• In T2, we also switch the specifications for RoutFrac and the molar composition of the bottoms product. We specify the concentration of methanol in the wastewater stream at 250 ppmw.