Solving for x:
9:294 þ 222 x ¼ 0:923 þ 1,162 x
x ¼ 8,905 lb=h
Mole weight of reflux ¼ 18:5 from the dew point calculation
ð
Þ
Moles=h reflux ¼ 481
The moles of vapor from the reclaimer will be added to this figure when calculating
the vapor loading over the top tray. Two trays above the feed tray will be provided
as wash trays.
The Stripper Bottom Conditions and Reboiler Duty
The pressure at the bottom of the tower is fixed at 34 psia. This allows a pressure
drop of about 0.35 psi per tray which is estimated as a total of 20 trays. The tower
Reflux
Feed
x
Product
Envelope 1
Envelope 2
Fig. 4 Heat balance envelopes for tower overhead
Table 6 Overhead heat balance example
Stream
V or L
F
lb/h
Btu/lb
MMBtu/h
In
Total O/head
V
218
16,458
615
10.122
Total in
10.122
Out
Prod
V
100
7,506
155.7
1.169
Reflux
L
100
8,952
92.5
0.828
Condenser
By
Diff
8.125
Total out
16,458
10.122
522
D.S.J. Jones and S.A. Treese
9:294 þ 222 x ¼ 0:923 þ 1,162 x
x ¼ 8,905 lb=h
Mole weight of reflux ¼ 18:5 from the dew point calculation
ð
Þ
Moles=h reflux ¼ 481
The moles of vapor from the reclaimer will be added to this figure when calculating
the vapor loading over the top tray. Two trays above the feed tray will be provided
as wash trays.
The Stripper Bottom Conditions and Reboiler Duty
The pressure at the bottom of the tower is fixed at 34 psia. This allows a pressure
drop of about 0.35 psi per tray which is estimated as a total of 20 trays. The tower
Reflux
Feed
x
Product
Envelope 1
Envelope 2
Fig. 4 Heat balance envelopes for tower overhead
Table 6 Overhead heat balance example
Stream
V or L
F
lb/h
Btu/lb
MMBtu/h
In
Total O/head
V
218
16,458
615
10.122
Total in
10.122
Out
Prod
V
100
7,506
155.7
1.169
Reflux
L
100
8,952
92.5
0.828
Condenser
By
Diff
8.125
Total out
16,458
10.122
522
D.S.J. Jones and S.A. Treese