1 reply to this topic

[Gabe G.]

Hello,

First time poster and long time reader of the site.  I have found many useful discussions in these forums over the last few years of my young career (4 years) in midstream natural gas and appreciate your responses to my question.

 

My question concerns the general design of TEG dehydration systems.  It seems to be common place that the carbon filter is placed on the rich side of the system before the glycol regenerator.  What is the reasoning for having the carbon filter in this location as opposed to the lean side of the system?  Does it cause operational issues with the regeneration system?  Here are a few explanations that i can think of that i would like to be vetted by this community.

• Since the carbon filter removes hydrocarbons, compressor oils, and TEG degradation products from the TEG, having the filter on the lean side would cause these components to build up and cause issues with foaming, sludge, or coking inside the regenerator.
• Placing the carbon filter on the low pressure lean side could potentially lead to pressure drop and pump cavatation issues.
• Placing the carbon filter on the high pressure lean side would require a higher pressure rating on the vessel and a larger capital cost.
• Buildup of entrained hydrocarbons in the regenerator could impact the operation and accuracy of level instruments in that unit due to the lower gravity of the hydrocarbons than TEG

I appreciate any feedback on these ideas and would like to receive any other considerations as to why is it preferred to place the carbon filter on the rich side of the TEG dehydration system.  Also, if there are situations where it is advisable to place the carbon filter on the lean side (in either high pressure or low pressure service) it would be useful to know those as well.  Thanks again.

 

Cheers,

Gabe G.

[chinbas]

Hi Gabe G,
I am also an inexperienced engineer like you (1 year in design!). HAVING SAID THAT I will try to add some thaougt behind it.

Acording to my consideration main reson of putting curbon fileter ahead of regeneration unit is to remove hydrocarbon (volatile ) ahead of glycol glycol heat exchnager. Because if there is any hydrocarbon it will create bubble in the surfce of heat exchnager. Which interns will cause pitting corrosion.

Another concern is foam in the still column. A small amount of hydrocarbon can cause serious foaming problem in still column. Which will cause glycor Cary over.

Please correct me if I am wrong.

Have a look of Mr Ankur's document given by Sivalls. And try to study literature like Glycol Dehydration manual by Mr. Arnold

REGARDS