Inlet Head in Inches of Hot Liquid, h i When there is an inlet weir, use:
h i ¼ 0:06 GPM Ä N p Á L i
À
Á
Â
à 2=3 þ h wi
(12)
where:
h i = tray inlet head in inches of hot liquid
L i = length of inlet weir in inches
h wi = height of inlet weir in inches
Where there is no inlet weir, then h i = h cl .
Downcomer Filling in Inches of Hot Liquid
L d ¼ h i þ h t þ h ud
ð
ÞÁ ρ 1 Ä ρ 1 À ρ V
ð
Þ
½
Š þ 1:0
(13)
where:
L d = downcomer filling in inches of hot liquid
Example Tower Sizing Calculations
The following is an example of tower sizing and hydraulic analysis. Tray loading
data that is used for this example are those calculated for the debutanizer column
earlier in this chapter. Thus, all data are at tray conditions of temperature and
pressure (Table 17):
Bubble area on top tray at flood:
G f ¼ K√ ρ v  ρ 1 À ρ v
ð
Þ
ð
Þ
(14)
where:
G f = load at Flood in lb/h ft
2
K = 1,110
Table 17 Example tower
sizing basis
Vapor
Top tray
Liquid
Top tray
Moles/h
1,012
lb/h
46,803
lb/h
57,297
GPM
187
ACFS
14.3
CFS
0.147
ρ v lb/cuft
1.11
ρ l lb/cuft
31.18
Vapor
Bottom tray
Liquid
Bottom tray
Moles/h
1,223.9
lb/h
239,860
lb/h
107,695
GPM
768.4
ACFS
8.7
CFS
1.715
ρ v lb/cuft
3.44
ρ l lb/cuft
38.9
Distillation of the ‘‘Light Ends´´ from Crude Oil in Petroleum Processing
223