Page 361 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

b. E-105
c. P-101
d. C-101
e. T-101
f. H-101

Compare your findings with the information given in Chapter 1.
a. V-102 High-Pressure Phase Separator
From Table 11.6, we use the following heuristics:
Rule 3→Vertical vessel
Rule 4→L/D between 2.5 and 5 with optimum at 3.0
Rule 5→Liquid holdup time is 5 min based on 1/2 volume of vessel
Rule 9→Gas velocity u is given by

where k = 0.0305 for vessels without mesh entrainers
Rule 12 → Good performance obtained at 30%–100% of u from Rule 9; typical value is 75%
From Table 1.5, we have

Vapor flow = Stream 8 = 9200 kg/h, P = 23.9 bar, T = 38°C
Liquid flow = Streams 17 + 18 = 11570 kg/h, P = 2.8 bar, T = 38°C
3
3
ρ = 8 kg/m and ρ = 850 kg/m (estimated from Table 1.7)
υ l
0.5
From Rule 9, we get u = 0.0305[850/8 – 1] = 0.313 m/s
Use u = (0.75)(0.313) = 0.23 m/s
act
2
Now mass flowrate of vapor = uρ πD /4 = 9200/3600 = 2.56 kg/s
υ
Solving for D, we get D = 1.33 m.
2
From Rule 5, we have volume of liquid = 0.5 LπD /4 = 0.726L m 3
5 minutes of liquid flow = (5)(60)(11,570)/850/3600 = 1.13 m 3
Equating the two results above, we get L = 1.56 m.
From Rule 4, we have L/D should be in range 2.5 to 5. For our case L/D = 1.56/1.33 = 1.17
Because this is out of range, we should change to L = 2.5D = 3.3 m.
Heuristics from Table 11.6 suggest that V-102 should be a vertical vessel with D = 1.33 m, L = 3.3
m.
From Table 1.7, we see that the actual V-102 is a vertical vessel with D = 1.1 m, L = 3.5 m.

We should conclude that the design of V-102 given in Chapter 1 is consistent with the heuristics given in
Table 11.6. The small differences in L and D are to be expected in a comparison such as this one.
b. E-105 Product Cooler
From Table 11.11 we use the following heuristics:

Rule 1: Set F = 0.9
Rule 6: min. ΔT = 10°C
Rule 7: Water enters at 30°C and leaves at 40°C
2
Rule 8: U = 850 W/m °C

We note immediately from Table 1.5 and Figure 1.5 that Rule 6 has been violated because ΔT min = 8°C.