Process mode for the A8 example simulation

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

• For the high-pressure column, we switch specifications for the reflux ratio and the molar composition of the top product so that the reflux ratio is calculated. We specify the oxygen composition at 10 ppm in the top product stream.

• In the low-pressure column, we calculate the boilup ratio and specify the overhead product composition. Like the high-pressure column, the boilup ratio is calculated and we specify the oxygen composition at 10 ppm in the top product stream.

• We add an equation to the flowsheet to calculate the argon recovery (the total moles of argon leaving the argon column divided by the moles entering). We specify the ArgonRec variable at 0.333 and the reflux ratio of the argon column is calculated.

• We supply an additional flowsheet equation so that the heat duty of the low-pressure column reboiler equals the heat duty of the high-pressure column condenser.