Dehydration · Gas Plant
Glycol Dehydration
A contactor where triethylene glycol (TEG) absorbs water from the gas, and a skid that boils the water off the glycol so it can be reused.
What it does
Dries the gas to the sales gas water specification. Lean TEG of just under 99 percent purity enters the top of the contactor; the rich glycol goes to a flash tank, where most dissolved gas comes off, and then to a reboiler kept below the temperature where TEG breaks down.
Basics
| Glycol | Triethylene glycol (TEG) |
| Reboiler | About 380 to 390 °F (193 to 199 °C); TEG breaks down above this range |
| Sales gas water | 4 lb/MMscf in colder North America, 7 in warmer areas |
| Emissions | BTEX and VOC from the still vent |
Common failures
- Glycol degraded by an overheated reboiler
Troubleshooting
- Symptom
- Gas water content above spec
- Likely cause
- Low lean glycol purity
- What to check
- Check reboiler temperature and stripping gas