Page 215 - Separation process principles 2

180 Chapter 5 Cascades and Hybrid Systems

Table 5.3 Degrees of Freedom for Separation Operation Elements and Units
Element or NV, Total Number of NE, Independent ND, Degrees
Schematic Unit Name Variables Relationships of Freedom
Total boiler (reboiler) (2C + 7)

Total condenser (2C + 7)

Partial (equilibrium) (3c + 10)
boiler (reboiler)

Partial (equilibrium) (3C + 10)
condenser

(el vout Lin Adiabatic equilibrium (4C + 12)
H
stage

Vin
Lout
(f) vout Lin Equilibrium stage with (4c + 13)
heat transfer

Vin Lout
I
I (g) vout L1n Equilibrium feed stage (5c + 16)
with heat transfer
I
and feed
11 1 F+Q vln Lout

(h) Vout Ll" Equilibrium stage with (5C + 16)
heat transfer and
- : 1 as - Q sidestream

'In Lout
(i) VoutL,n N-connected (7N+2NC+2C+7) (5N+2NC+2) (2N+2C+5)
equilibrium stages
@
with heat transfer
QN
Stage N
QN-I
Q2
Stage 1
Ql
Lout
"1,
Stream mixer

Stream divider (3C + 10) (2C + 5) (c + 5)

"Sidestream can be vapor or liquid.
b~lternatively, all streams can be vapor.