Page 307 - Process Equipment and Plant Design Principles and Practices by Subhabrata Ray Gargi Das

11.4 Fractionator 309

Start

Specify feed

Specify split of light and heavy key

Estimate split of non-key components

Decide condenser type. Estimate column pressure

Flash feed at column pressure
[Adiabatic flash calculation]

Re-estimate split of non-key Calculate minimum no. of ideal stages
components and column [Fenske equation]
pressure
Calculate split of non-key components
[Fenske equation]

Yes Estimated and
calculated split of non-
keys differ considerably

No
)
Calculate minimum reflux ratio (R mn
[Underwood equation]
Calculate no. of stages for specified reflux
) [Gilliland correlation]
ratio (R). (R>R mn
Calculate feed stage location
[Kirkbride equation]

Calculate reboiler and condense duties
[Energy balance]

Stop

FIGURE 11.12
Flow chart for multicomponent distillation column design by F-U-G method.