Building simulations
Columns, flashes and separations
Every separation here is an equilibrium calculation with the property method you chose — so the method matters most where the phases are hardest to predict.
Flash drums and liquid splits
- A flash drum takes any two of temperature, pressure, duty and vapour fraction: T and P, adiabatic at a pressure, a duty and a pressure, or a vapour fraction with P, T or the duty.
- A decanter and the three-phase separator split two liquids. They need an activity model that can form a second liquid — NRTL or UNIQUAC.
- A component splitter sends each component where you say — for a separation you haven't designed yet.
Shortcut distillation
- Give the light and heavy keys and how much of each goes where, then either R/Rmin (it computes the stages) or the number of stages (it computes the reflux).
- It reports the minimum reflux and stages, the feed stage and both duties — Fenske, Underwood, Gilliland and Kirkbride. The fastest way to size a column before running it rigorously.
Rigorous distillation
- Give the stages (condenser and reboiler included), the feed stage, the reflux ratio and one capacity specification: distillate rate, bottoms rate or reboil ratio.
- Total or partial condenser; a second feed or a side draw adds a port; Murphree efficiency for real trays.
- Analysis → Profiles charts temperature, flows and compositions stage by stage.
- If it does not converge: start from the shortcut column's reflux and stages, check that the keys can actually be split at that reflux, and try the other convergence solver.
Absorbers and gas treating
- The absorber / stripper is a stage-by-stage equilibrium column, isothermal or adiabatic.
- The amine contactor and amine regenerator model CO₂ and H₂S absorbed chemically into MEA, DEA or MDEA, with the loading, the lean and rich streams and the reboiler duty.
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