Page 328 - Petroleum and Gas Field Processing

1
9. Check pressure drop across the bed for a -in. particle size of
8
packed material, the pressure drop can be calculated as
P 2
¼ 0:056 V g þ 0:0000889 þ V g ð21Þ
h B
It is recommended that the pressure drop should be less than 8 psia.
The design procedure is illustrated in Figure 11.

Example 5
Given that 35 MMSCF of wet gas is fed into a packed bed of desiccant.
3
The gas molecular weight is 18.0 and its density is 1.5 lbs/ft . The
operating temperature is 110 F and pressure is 500 psia. The inlet dew

point is 100 F and the desired outlet dew point is (1 ppm H 2 O).
Solution
Assuming
X C ¼ 0:12

35ð90Þ
W B ¼ ¼ 8750
3ð0:12Þ
8750 3
V B ¼ ¼ 195 ft
45
1
Assume -in. particle size.
8
1
D P ¼
8ð12Þ
1=2
1 ft

V g ¼ 540 ¼ 45
8ð12Þð1:5Þ min
1=2

25ð35Þð1Þð70Þ
d ¼ ¼ 3:9ft
600ð45Þ
V B 195ð4Þ
h B ¼ 2 ¼ 2 ¼ 16:3ft
d =4Þ ð3:9Þ
GW 35ð90Þð0:053Þ

q ¼ 0:053 2 ¼ 2
d ð3:9Þ

is the gas viscosity in centipoise, Cp.

Copyright 2003 by Marcel Dekker, Inc. All Rights Reserved.