DEW POINT WATER VAPOR TUBE 177UR
METHANOL CORRECTION WORKSHEET
Background
Methanol is added to natural gas pipelines to prevent hydrocarbon freezing in cold weather and at
deep water off-shore wells. The presence of methanol causes Dew Point Water Vapor Tube
No. 177UR to read high. When methanol is known or suspected to be present in the gas stream,
follow the steps below.
Procedure
1) Determine the level of methanol (in ppm) b in the pipline, using Sensidyne Tube No. 119U.
2) Determine the uncorrected level of water vapor (in LB/MMCF) c using Tube No. 177UR.
3) Use the chart below to determine the correction factor (in LB/MMCF) d.
4) Subtract d from c to obtain the corrected reading e.
14
13
12
11
10
Correction Factor
(in LB/MMCF)
CUSTOMER WORKSHEET
16333 Bay Vista Dr. • Clearwater, FL 33760 • 800-451-9444
727-530-3602 • Fax: 727-539-0550 • www.sensidyne.com
9
8
7
6
5
4
3
2
1
0
0
10
20
30
40
50
60
70
Methanol
(ppm)
b
c
d
e
Methanol Level
(ppm)
Uncorrected
Water Vapor Level
(in LB/MMCF)
Correction
Factor
(in LB/MMCF)
Corrected
Water Vapor Level
(in LB/MMCF)
Use Chart
Technical Questions?
Contact our Answer Center at
1-800-451-9444, ext 782
© 2001 Sensidyne, Inc.
H&S 4110 Rev A 0106