2 replies to this topic

[alex.gutu]

Dear all

Everybody of you knows amine treating unit and their operation parameters. As I have seen, in the the most of Amine Sweetening Units the regeneration column for amine operates at very low pressure, I mean somewhere about 0.5-1 barg because of the problem of amine degradation.
As far as I know, the amine degradation temperature is somewhere about 125-130C depending on concentration. having a look through the internet, I could find out that basically the bottom temperature of the regeneration column is about 133C, maximum 135C, depending on the pressure and concentration. So...it's perfect, but I have a question regarding regeneration column of amine.
I started to simulate (in Aspen HYSYS) a simulation for amine sweetening plant. Feed stream is natural gas with 30% content of CO2, and I want remove it up to 3 %. So at the low pressure (0.5-1 barg) everything works fain, but I have a restriction in the top of the column, more exactly 3 barg for acid gas CO2. So, to get in top 3 barg, I have to get in the bottom somewhere about the 3.2-3.3 barg, and in this case the boiling temperature of the amine solution is about 148-150C. Now, I'm asking you what about with amine solution, the degradation temperature of amine solution seems to be exceeded and I'm aware of the amine degradation.
Could anybody tell me, or suggest me how could get a regenerated amine solution at a working pressure of 3 barg in the column.

Maybe should I use another philosophy for remove CO2 from sour Gas?
What kind of methods are used to remove CO2 and H2S from natural gas at pressure higher than 1 barg. Are there used another solutions beside amine solutions?

Sincerely,
A.G.

[Profe]

Hi Alex

Regarding your concerns about design of amine regeneration column. The operating pressure of the regeneration system of top drum is between 0.5 to 1.5 bar, because within this range of pressures is that the regeneration temperature be within the allowable limits to prevent amine degradation. The design pressure of the equipment believe is between 3 - 3.5 barg as established criteria regarding equipment design operating pressure. Reviewing the GPSA ENGINEERING DATA BOOK section 21 "Hydrocarbon treating" you can find more information about this topic and other aspects related to CO2 at higher pressures.

Otherwise, search in this site about this subject for more help.

Good luck

Edited by Profe, 16 June 2011 - 09:34 AM.

[Art Montemayor]

Alex:

First of all, your queries are too general and not specific. You either are a student, a very young graduate, or you don’t have any experience with acid gas removal systems. In either case:

You need to specify WHAT AMINE you are dealing with. MEA, TEA, DEA, MDEA, etc., etc. Each amine has specific temperature limits – depending on its solution concentration – with regards to its regeneration. Please don’t generalize. We could be on this thread for months.

No amine solution has a definite, “fine-line” definition as to its regeneration temperature limits. There are general ranges of degradation and no constant, specific temperature values. Amine solutions degrade due to a variety of reasons. Again, you have to be specific. For details, read and study Kohl and Riesenfeld’s book, “Gas Purification” as well as all the free literature at Bryan Research and Engineering, Inc. - http://www.bre.com/.

Amine solutions have – and are been used for removing acid gases since before I was born (and that’s a long time!). The optimum amine and the solution strength depends on the type of gas, its composition, pressure, temperature, and removal level.