Page 321 - Petroleum and Gas Field Processing

(c) Target gas water content ¼ 7 lb/MMSCF
(d) Use TEG for dehydration (98.5% purity, the balance is water)
(e) No stripping gas used

Solution

Absorber Diameter
Calculate Z, the compressibility factor:
T r ¼ 1.6317, P r ¼ 1.5217

0
B ¼ 0.1100, B ¼ 0.1170
B r ¼ 0.1092
ð 0:1092Þð1:5217Þ
Z ¼ 1 þ ¼ 0:898
1:6317
Calculate the volumetric flow rate, V:
PV ¼ nZRT
6
ð98 10 =379:5Þð0:9Þð10:7Þð560Þ
V ¼
1015
ft 3
V ¼ 953
min
Applying the Souder–Brown equation;
1=2

ð70 3:79Þ ft ft
U max ¼ 660 ¼ 2759 ¼ 46
3:79 h min
The cross-section area of the column is now found to be
953 2
A ¼ ¼ 20:7ft
46
r ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
4ð20:7Þ
D ¼ ¼ 5:1ft

Absorber height
To calculate the number of theoretical plates, first plot the operating
line:
At tower bottom, calculate Y 1 from Figure 6:
Y 1 ¼ water content of inlet gas ¼ 63 lbs H 2 O/MMSCF
Calculate X 1 from column material balance, where X 1 is the
rich glycol weight percent
At tower top,
Y 2 ¼ water content in exit gas ¼ 7lbs H 2 O/MMSCF (given)

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