2 replies to this topic

[B-2 Spirit]

Dear All,

 

I am currenly working on a gas plant consisiting of Compressor, AGRU and TEG dehydrtaion units. I have to decide the Design pressures & temperatures of various equipments. While the Compressors and downstream Gas treatment sections like Amine column and TEG column will be designed for compressor shut-in, I am facing a bit of delimma deciding the design temperature and pressures for the Amine Regenration column and TEG reboiler.

 

Both the systems operating at relatively low pressures 4.5 bar a for Amine Regeneration &  below 2 bar a for TEG reboiler.

The heat source for Amine regeneration is LP steam, where as that for TEG reboiler is HP steam.

 

For Amine regenerator column, I have calculated a design pressure of 5.2 barg (applying margins as per BOD)and temperature of 160 deg C designed for LP steam

 

similarly, For TEG reboiler I have  calculated a design pressure of  3.5 barg and 293 deg C for HP steam.

 

Friends, do I need to consider any other condition for reaching the deisgn pressure & temperatures. especially for TEG reboiler do I need to consider tube rupture which will bring the design pressure of reboiler to 10/13 of 46 = 35.4 barg?

 

 

thanks and regards,

B-2 Spirit.

 

[Art Montemayor]

  

B-2 Spirit:

 

Please define your acronyms.  Not everyone knows what an AGRU (Acid Gas Removal Unit?) or a BOD is.

 

Your post is somewhat confusing.  Why do you have to decide the design pressures & temperatures of various equipment?  Is the equipment already in place and operating?  Or is it in the design stage?  If it is operating, the design conditions have already been decided.

 

Why are you concerned with the regeneration portions of the Amine and TEG units?  If you have a shutdown, these are normally blocked off automatically.  Additionally, why are the Amine and TEG reboilers (and their respective strippers and exchangers) operating at such a high pressure?  Both Strippers and their reboilers should be operating at as low a pressure as you can tolerate due to the back pressure cause by downstream instruments or equipment.  Normal pressures are usually:  Amine stripper = 3-8 psig and TEG stripper = 1-3 psig.

 

Another confusing (and impossible) bit of information you cite is that you are using steam to regenerate the TEG.  Lots of luck with that; it will never happen.

 

Please be specific in you explanations to the above questions and tell us exactly what you are proposing to do.  It is a waste of time and effort to address impossible conditions like trying to heat TEG to 400 ^oF with steam.

 

Also tell us if you are a graduate engineer or still a student.  The quality of your post requires you tell us that in order to better help you.

 

[B-2 Spirit]

Art,

 

Thanks for your comments and criticism. I will take care of these aspects in my next post. 

I am working in the design phase of the project.

I am extremely sorry for giving wrong information out of my ignornace in gas processing systems. The HP steam is definitely not going to work in this case.

I am a Process Engineer with experience in Refinery and Petrochemicals. But new to gas processing systems.

 

thanks and regards,

B-2.