foaming problem in glycol contactor.

[I2P]

friends,
We have a gas glycol contactor which has been experiencing foaming problems recently. What are the causes( apart from hydrocarbon condensation) which result in foaming? what are the remedial causes? A comprehensive answer is welcome.

 

[tickle]

Could be that the glycol is too hot - try a gas glycol exchanger on the inlet.

COuld be too high a gas velocity.

Is it a tray column or a packed column

Has it always foamed? Has there been a change in pressure or flowrate?

 

[bspooner]

Get an analysis done on the glycol and check for degradation and/or low pH. These can contribute to foaming.

I'm also a big believer of using the reboiler to not only boil off water but also other contaminants. Run it at 200C and circulate as slow as possible.

In Alberta oleyl alcohol is a commonly utilized antifoam for in the meantime.

Ben Spooner, P. Eng
Process Engineer
Amine Experts Inc
Calgary, Alberta

 

[I2P]

bspooner,
Thanks for your input. I would like to know what exactly to look for in the detaile analysis of glycol. We have visually checked the appearance of the glycol and it is dark brownish in colour, besides the ph is found to be above 7. The temperature at which we run the reboiler is 200 deg C.Our circulation rate is 2500 kg/hr, and this is as per the vendor's operating procedure. Do you think we can still operate at lower rates? How do u think the slow rate of circulation will help?
Further from a purely theoretical standpoint and for a better understanding of the problem could u enlighten me as to the root causes of foaming? ie all possible sources/ conditions/parameters/contaminations etc.
What is a typical glycol analysis? what should be the specifications and what are the limits and deviations?
Thanks and regards

 

[25362]

Glycol decomposition happens at above 400^oF. Film temperatures may be higher if the bulk is at 400^oF.

May be the following sites can give you some ideas:

http://www.pete.lsu.edu/Courses/Edwards/pete4085/handouts/Glycol_Dehydration.pdf

http://www.natcogroup.com/Research and Development.htm

http://www.bre.com/technicalpapers/technicalpaper.asp?articlenumber=34

 

[tickle]

As I stated before, have you checked the gas superficial velocity.

Additionally do you have a carbon/charcoal filter in the loop? This will remove a lot of organic contaminants. If you do have a carbon filter, when was the last time that you changed the carbon?