5 replies to this topic

[yul]

Hi All,

I'm a new process engineer in gas treatment plant. Currently we have experienced a lot of foaming incidents in the absorber column which had led to the plant trip. We are thinking of liquid hydrocarbon that caused the problem, but we couldn't find any hydrocarbon layer during skimming (daily). Can someone give some ideas on this matter? What is the effect of dissolve hydrocarbon and aromatic to foaming problem?

And what is the best way to prevent heavy hydrocarbon from entering the absorber. At the moment, we only have one knockout vessel equipped with SMSM (Schopentoter, demister, swirldeck and demister)

Regards,

Yul

[Art Montemayor]

Yul:

As is usual, you fail to tell us any of the basic data to fully analyze and help out. We can't help if we are kept starved of data and fed only litlle crumbs, one at a time.

As in all gas processing plants, yours certainly had an engineering company that scoped it, specified it, designed it, constructed it, and started it up. The successful plant startup probably led to an official "turn-key" ceremony where your company (or owner) officially and legally took possession of what they bought from the Engineering Contractor.

Consequently, you (& your company, as the "owner") are the ones who should hold all of the important information having to do with this plant. Wasn't the plant operation guaranteed? If not, then who is responsible for the proper and correct operation of the plant? Doesn't the original Engineering Company give you any customer service? Have you had them visit the plant? Have you requested help from them? What have been the responses?

I think that if you have a serious gas treating operational problem, you should refer directly to those that designed and constructed the facility. They have (or should have) all the original design information and operating instructions.

You are not going to resolve this problem through our Forum when we don't even know what treating process you are operating. We know virtually nothing about your plant because you have offered us nothing in the way of basic data.

Sorry.

[vishtech03]

You have not mentioned whether you are using any antifoam. If so,it could be due to lesser injection or even over injection. Correct the quantity as specified by the BEDP. If you are not using any antifoam at all, try dosing 0.25-1.0 ppm of silicon based antifoam agent.

[engprocess]

Yul,
Read the book: Troubleshooting process operations (Lieberman,1991)... you find what are you asking for.
Hope this will help you

Youcef

[HMAlmosa]

Yul,

This is a copy of an answer I have posted to a similar question in the oil & gas forum.
The way to reduce probability of foaming (which can happen in the contactor or regenerator) in amine units is as follows:
1) Unit needs to be sized properly to handle the expected loads
2) Keep the lean amine inlet to contactor temperature at least 5 deg.F warmer than the feed gas temperature to prevent HC liquid condensation in contactor.
3) You need a filter/separator upstream of the contactor to remove HC liquid and solids from feed gas
4) You need good amine filtration on the rich and lean side to remove corrosion products and other dirt. 10% Slip stream filtration is normally enough. Replace filter elements as they plug up.
5) You need an carbon filter to absorb free HC liquids. Change out when it gets saturated.
6) Include HC liquid skim points in your design.

When foaming occurs, you can fight it as follows:
1) The fastest and most effective way is to inject anti-foam. Certain amines are very prone to foaming (such as MDEA) and may require continuous anti-foam injection. However, MDEA selectivity to H2S and low corrosivity still make it very attractive for many applications.
2) Consider reducing the gas rate temporarily until the system recovers from foaming.

Some times foaming is blamed for problems not related to foaming. Other causes of problems could be mechanical such as plugged trays or downcomers, or collapsed trays, or plugged heat exchangers, in addition to a host of other possibilities. You need to analyze all the symptoms of the problem to figure out which part of your system is the culprit. I hope this helps.

I had endeavor to solved the foaming problem in amine contactor from 2007, the way is not same as mentioned above but changing the column internals, spray contact condition could prevent foaming, the two DN2400 absorber had retrofit, now it is very stable. certainly the impurities still under removeling but not with very strong measurements and hard work.

Edited by traydesign, 08 February 2012 - 12:27 AM.