McKetta-Wehe · GPSA · Pipeline Dehydration Specs
Pipeline tariffs typically require <7 lb/MMSCF or a water dewpoint of 32°F. Cryogenic plants need <1 ppmv (<0.1 lb/MMSCF). Arctic pipelines may require -40°F dewpoint.
Water content prediction, dewpoint specs, dehydration method comparison, hydrate prevention through dewatering
Evaluates gas dewatering requirements using McKetta-Wehe water content correlation and GPSA dehydration method selection guidelines.
| Method | Dewpoint | Cost |
|---|---|---|
| TEG Glycol | -40 to 32°F | Low-Med |
| DEG Glycol | 0 to 40°F | Low |
| Mol. Sieve | -150 to -60°F | High |
| Refrigeration | 15 to 40°F | Med-High |
| CaCl2 | 30 to 50°F | Very Low |
Water content in natural gas is determined by temperature and pressure. Higher temperatures increase water carrying capacity while higher pressures reduce it. The McKetta-Wehe chart is the industry-standard method for sweet gas; acid gas correction factors are applied for CO2 and H2S content per GPSA.
Gas dewatering is the primary method for preventing hydrate formation. Reducing water content below the saturation point at the coldest expected pipeline temperature eliminates free water and prevents hydrate nucleation. For gathering systems, target a dewpoint 15-20°F below the minimum ground temperature.