GPSA · API 12GDU · Sivalls Method
Elevation reduces atmospheric pressure (~1 psi per 2,300 ft), lowering water's boiling point. The same glycol purity is achieved at lower reboiler temperatures at altitude.
TEG/EG properties, contactor design, GPSA methods, circulation rates, and Sivalls reboiler duty calculations
Designs glycol dehydration systems per GPSA and Sivalls methodology for natural gas dehydration and freeze protection.
| Property | TEG | EG |
|---|---|---|
| Primary Use | Dehydration | Freeze Prot. |
| Max Reboiler | 400°F | 320°F |
| Degradation | 404°F | ~329°F |
| Vapor Pressure | Very Low | Low |
| Viscosity | Higher | Lower |
GPSA data shows water removal curves flatten at 3–3.5 gal/lb. Higher rates increase reboiler duty without improving dehydration. For absorbers with ≥3 equilibrium stages, 3 gal/lb is the design standard. Lower rates risk insufficient dew point depression.
TEG begins thermal decomposition at 404°F. Limit reboiler to 390°F for safe operation. For >99.5% purity, use stripping gas (2–10 SCF/gal) rather than higher temperatures. DEG degrades at 328°F — avoid in high-temperature applications.