Mode summary for the AA2 example simulation

Process mode

The objective of Process mode is to provide an overall mass and energy balance for the process and to estimate product temperatures and compositions. In Process mode, we take the following steps to meet the process specifications:

• For the plate-fin heat exchangers (E1, E2, and E3), we specify the surface area, pressure drop, outlet temperature, and heat transfer coefficient for each hot and cold path.

• We specify the pressure change and efficiency of the EX1 expander and the K1 compressor.

• We specify the molar flowrate of LN2 and calculate E1.Tco[1].

Fluid Flow mode

Fluid Flow mode serves as an intermediate calculation before dynamic simulation. Process mode performs flow-driven, steady-state calculations that are a good basis for subsequent process design. When you switch to Fluid Flow mode, the simulation converts from a flow-driven model to a pressure-driven model. Typically, you do not specify flowrates in this mode. Instead, you calculate the flowrates by balancing pressures on each piece of equipment.

Dynamics mode

Dynamics mode allows you to observe process behavior during and after a process disruption or change. For this example, we examine the impact of throttling the XV1 valve on the refrigeration loop temperature.