3 replies to this topic

[abo annas]

Hi to all,in our glycol treatment unit, there is signs of exssive foaming in the reboiler,what are the reasons for that? and if we add some anti foam to the glycol contactor it well help? all technical openions from expert staff on this forum are wellcome....
best regards

[Erwin APRIANDI]

Hi Abo,

1. Foaming on glycol system can be promotes by the existance of
• hydrocarbon liquids;
• field corrosion inhibitors;
• salt;
• finely divided suspended solids.
So first I will suggest you, analyse the glycol composition to see what is causing the problem
I presume that your plant will have a lab, or you can take it to comercial lab for testing

The foam is generated because of the promoter in the solution and there is an excessive turbulence and high vapour-to-liquid contacting velocities which will usually cause the glycol solution to foam

2. Addition of Anti Foam will it help? Yes it will help, however an addition of Anti Foam should be regarded as a temporary control until the foam promoters can be determined and eliminated.
The success of the Anti Foam is usually dependent upon when and how it is added. Some Anti Foams, added after the foam is generated, will act as good inhibitors, but, when it is added before foam generation, act as good foam stabilisers, which makes the problem worse. Most Anti Foams are deactivated within a few hours under high temperature and pressure conditions and their effectiveness can be dissipated by the heat of the glycol solution. Anti Foams should generally be added continuously, a drop at a time, for best results.

The most satisfactory cure for foaming problems is proper care of the glycol solution. The most important measures to achieve this are effective gas cleaning ahead of the glycol system and proper filtration of the circulating solution.

Edited by erwin.apriandi, 19 May 2011 - 09:35 PM.

[abo annas]

thank you very much for these valuble information...
best regards
Abo Annas

[M S Miglani]

While I agree with Ervin's views. I would like to add that you can check following operating parameters
1. Whether there is a high level in the Feed KOD?
2. Whether do you have atleast +5 C temperature difference between Glycol entering the Absorber and wet gas temperature?
3. Whether filtration system is in line. Just ensure that filter elements have not bursted. In one plant, I visited, there was very less pressure drop across the filters. While cheching the DCS logs we observed that the pressure drop was increasing over months and suddenly it decreased. When the filter was opened it got bursted. In case you have a spare installed filter, you can just take the other filter inline.


The proper maintenance of above operating parameters will reduce the foaming problem. Anti foams can be used intermittently in case you have foaming problems but setting the right operating parameters will only help you in long run.