CO₂ Freeze-Out Screen
Estimates the temperature at which solid CO₂ forms from a cold gas stream (solid-vapor equilibrium), the margin to your operating temperature, and the maximum allowable CO₂. Validated against CO₂'s −78.5 °C dry-ice point. Per GPSA §16.
Solid-vapor screen. This models CO₂ freezing from the vapor. Freezing in the cold liquid (demethanizer) needs the ZareNezhad-Eggeman / GPSA solid-liquid model. Evaluate every cold point — the limiting location is often mid-column.
Stream Conditions
mol%
psia
°F
Engineering Basis
Solid-vapor: CO₂ freezes when yCO₂·P·φ = Psub(T).
ln(Psub, mmHg) = 22.73 − 3134/T (anchored to CO₂ −78.5 °C @ 1 atm).
Freeze-out T = 3134/(22.73 − ln(yCO₂·P·φ)).
Max CO₂ at Top = Psub(Top)/(P·φ).
Standards: GPSA EDB 14th Ed §16; ZareNezhad-Eggeman (solid-liquid reference).