Material Selection on TEG (Glycol) Dehydrators
Material Selection on TEG (Glycol) Dehydrators
(OP)
I am trying to determine what type of material to select for the design of a TEG dehydrator.
The dehy will be used to strip the H20 from the gas stream.
My gas composition is mostly gas (mostly methane) with 20% of the stream being C02. The temperature in my contactor tower is 100 degrees F and the operating at pressure 400 psig
The 20% CO2 worries me. As of now my whole system is design with carbon steel (SA-516-70N). My question are as follows:
1. Will carbon steel be adequate in this enviornment?
2. Should I consider using SS for the tower internals (ie: the contacting tray, bubble cap trays)
3. Will there be any corrosion issue in my glycol reboiler?
4 Is there any specific codes that would make a decision?
Any suggestions would be appreciated.
Thanks!
The dehy will be used to strip the H20 from the gas stream.
My gas composition is mostly gas (mostly methane) with 20% of the stream being C02. The temperature in my contactor tower is 100 degrees F and the operating at pressure 400 psig
The 20% CO2 worries me. As of now my whole system is design with carbon steel (SA-516-70N). My question are as follows:
1. Will carbon steel be adequate in this enviornment?
2. Should I consider using SS for the tower internals (ie: the contacting tray, bubble cap trays)
3. Will there be any corrosion issue in my glycol reboiler?
4 Is there any specific codes that would make a decision?
Any suggestions would be appreciated.
Thanks!





RE: Material Selection on TEG (Glycol) Dehydrators
I wouldn't think there would be enough CO2 at the reboiler to cause issues but check your design to see what the CO2 distribution looks like in the stripper.
As for any codes to make the decision. No that is why they have engineers.
RE: Material Selection on TEG (Glycol) Dehydrators
I stated question 4 incorrectly.
Should state the following:
4. Is there any codes that I can reference to help in the decision making.
RE: Material Selection on TEG (Glycol) Dehydrators
1.
CS will only be adequate where lean glycol is predominant. In the contactor, this means above the lower tray or just above the structured packing. Below these limits, many operators have found that cladding with 316L is required probably owing to the high turbulence in the rich glycol at the bottom. The top portion can be in carbon steel with a suitable corrosion allowance.
2.
Most definitely
3.
Oh yes - this is the nastiest place with high temperatures and condensing acids. The still column should be 316L and then one may as well go the whole hog and have the reboiler vessel clad too.
4.
No public domain materials selection code exists for GDUs.
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Material Selection on TEG (Glycol) Dehydrators
In the dehydration column is not possibile to account for the inhibition of glycol, and usually the internal surface is clad with SS up to the injection of glycol.
S
Corrosion Prevention & Corrosion Control
RE: Material Selection on TEG (Glycol) Dehydrators
RE: Material Selection on TEG (Glycol) Dehydrators