Foaming in dehydration unit

[User101]

Hi

I would be grateful if any one can help me finding a photo of a column under foaming. Moreover, I would like to know if there is any online resources about foaming in dehydration units (i.e. TEG).

Thank You

 

[sapphire2004]

I am focusing on conquering the foaming problem of amine unit,and we use vertical sieve tray to solve it. The equipment is running at gas purification plant for more than 1 months.There is not any overflow and high pressure drop phenomenon.The rusult is still needed waiting for .

 

[User101]

Hi sapphire2004,

Thank you for your reply. I also concern about foaming in Amine processes. Could you give more information on the attached picture?

User 101

 

[dcasto]

There are articles on file at gasprocessors.com about foaming. DOW chemical published a book 40 years ago with information.

If you want to stop foaming, get the liquid hydrocarbons out of the gas stream. Add filters and plenty of Charcoal filters. This goes for both amine and TEG units. Everyone gets cheap with coalesors on the gas going into the contactor anf the Rich stream charcoal.

 

[sapphire2004]

it is an photo of an experiments tower which uses MDEA of absorber loacated at gas field. the conclusion is that the foaming is much more obvious at valve tray. especially the downcamer.but the vertical sieve tray have a better performance.

 

[dcasto]

For experimental data, you'll need to contact tray vendors.

 

[sapphire2004]

some intruments select structuring or random packing,in the book of gas purification, it suggest that type of internal can conquering the foaming to some degree.

chuangju technology Co.Ltd.

http://www.cj-chem.com

 

[dcasto]

No, type of internals is not a reliable way to control foaming. The type of internals will change the the capacity of a set diameter tower and the theroretical number of trays or tray efficicency.

 

[User101]

Hi Guys,

Yes, I agree with dcasto. The change of internal will affect the process and not the foaming phenomena.

Sapphire2004 mentioned that Gas Purification suggests this action but I think what has been mentioned in the book related to whether you can have a seive or valve tray or packing for system where foaming might be occured.

Packing offers the best option to min. foaming phenomena although most of the gas sweetening or dehydration towers in industry are trays !!!??? Designers might have other considerations more important than foaming.

Thank you all for your reply,

User101

 

[maddocks]

Foaming is now considered to be a function of fluid cleanliness as well as gas cleanliness. I can't see how internals have any effect on foam except for maybe higher tray spacing to allow for less foam entrainment up to the next tray. Filter the fluid well, filter the gas very well, monitor solution cleanliness, watch fluid surface tension, minimize the use of antifoams - especially silicone based.

Basically get the dust, mystery entrained molecules, and contaminants out of your gas before it enters the contactor.

 

[sapphire2004]

what kind of trays had you ever experienced? Is there something special like vertical sieve tray?
I don't agree with dcasto, Our trays has a different liquid-gas contact model.In our experiment tower-diameter 1800mm,the liquid is droplet,but gas is continuous phrase.so foaming is relatively less than valve trays.The total efficiency of tray for H2S is very good.
The analysis is undergoing.we will publish the analysis report in the near future.

chuangju technology Co.Ltd.

http://www.cj-chem.com

 

[dcasto]

sapphire, the paper should be sent to the Gas Processors association and presented at their annual convention. We'd all like to see this. It might be the next mirical since the Koch magic trays.

 

[sapphire2004]

The experiment onsite is still undergoing, so pls wait for some weeks.we have not got information of overflow caused by foaming

chuangju technology Co.Ltd.

http://www.cj-chem.com

 

[SeanB]

What is the temperature of your amine and what is the temperature of the feed gas?

 

[sapphire2004]

The temperature of amine entering the absorber is about 35 Celsius, temperature of feed gas is ranging from 5 to 15 Celsius.

chuangju technology Co.Ltd.

http://www.cj-chem.com

 

[SeanB]

Well that could very well be the cause of foaming. Typically you want to keep the amine at least 10 degrees cooler than the feed gas - this is to prevent foaming.

 

[sapphire2004]

if amine cooler than feed gas,the hydrocarbon will be cendensed down and enter amine, that maybe the exact factor for foaming.How do you come up with that idea?

chuangju technology Co.Ltd.

http://www.cj-chem.com

 

[maddocks]

Sean:

I strongly disagree - the amine must be warmer than the gas. Cooler amine will cause the gas to potentially condense hydrocarbons. While these hydrocarbon will not cause foaming, they may reduce surface tension causing the foam to be more stable and tougher to break. Most operators are now linking amine inlet temp to gas temp + 10 Deg F.

 

[User101]

Hi
I agree with Maddocks and Sapphire2004, 10 or more is good to avoid foaming.

sapphire2004
Your gas is a syngas or natural gas? and why you operate the plant at this low gas temp 5 C?

 

[SeanB]

Maddocks, I think you are right. I think I mixed those up. That will teach me to post something before I have my morning coffee.