7 replies to this topic

[shady othman]

hi

 

i am working in a NGL plant where we are treating propane from H2S and COS using Di-isopropanol amine in the AMINE unit with strength 18 % at pressure 25 barg and temperature 43 celsius, the problem that we are facing is the presence of high AMINE content in the treated propane.

 

please anybody have experience in this problem can advise me to the expected root causes of the problem and how to solve this problem.

 

Here you will finded an attachment for the PFD of the AMINE treating unit.

 

thanks

Attached Files

•  Book1.xlsx   543.04KB   18 downloads

[Art Montemayor]

There can only be 3 root causes for what you are experiencing in the product propane:

• The treating unit was not designed or built correctly in the first place;
• The treating unit is designed and built correctly, but not being operated correctly;
• The treating unit is designed and built correctly, but something internally has broken down or has been altered.

The background history of your unit, the experience of you and your operators, and your maintenance history will all be useful clues as to what can possibly be the true root cause,

[shady othman]

dear ART

 

thanks for your reply,

Our plant is correctly designed and built, also in the shutdowns check the internals are OK.

this will lead our thinking to your second suggestion which is incorrect operation, so can you explain for me what incorrect operations can be the cause of that problem

 

thanks

[Art Montemayor]

Shady:

 

By your comments, I have to assume that your unit has operated successfully at the designed capacity and conditions for an extended period and that it presently is also operating at the design conditions - or at less demanding conditions.  I also assume that ALL conditions are STEADY and continuous.

 

My second point has to do with process upsets, varying conditions, surges, or "spikes" in pressure, compositions, etc.  Also included is consistency in process instrumentation operations and controls.

 

I am presuming that your clean-up section downstream of your absorber has worked well in the past and has been maintained operating at the same design conditions as before with the same, accurate analysis instrumentation as before.  With all these checkpoints verified - as well as some more that are obviously related - your unit should perform successfully as before.  If it isn't, there has to be a point within your process that hasn't been checked or identified as yet.

 

These Unit Operations are not arcane or black magic.  They are very straight-forward and logical to understand, apply, and correct - if need be.  Persistence and detailed review are always your best tools in applying your engineering investigation into process operations.

[shady othman]

thanks ART,

 

what about feed change, is it can be the cause of the problem?

[Art Montemayor]

Shady:

 

When I wrote "the designed capacity and conditions for an extended period", any variances in feed and other incoming flow conditions are exactly what I meant.  The original design basis and conditions have to be respected in order to identify the acceptable operation of the process.

 

We are trying to relate to what confronted the original design and fabrication engineers of your unit and how they designed the appropriate and successful equipment to carry out the desired operation.

[shady othman]

dear ART

 

that means that I can't change the feed for the AMINE unit?

[Philip le Grange]

Hi Shady,

 

do you still have this problem? If the feed rate has not increased beyond prior limits increased foaming tendency in the system is a strong possibility.  Do you have a differential pressure gauge and if so does the differential pressure fluctuate in a manner that does not track feed rate?

 

Kind Regards,

Philip le Grange

(www.AmineExperts.com)