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DEHYDRATOR

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sege

Chemical
May 2, 2003
3
I have Tri-Ethylene glycol recommended for my Contactor(TEG Contactor).Presently, I have only a Mono Ethylene glycol available (MEG).Somebody should help to advise if it safe to go ahead and use the available or indicate the risk involved.Thanks

 
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I suggest you to go with your contractor recommendation, becuase of the following;

*TEG showed good practice as a solvent been used for Dehydration units, as it has less vapor lossess comapre to EG or DEG Solvent and good dew point depression.

*You need to look into the design of your unit,in term of water dew point spec.dry gas, I mean before selecting the solvent.

*Having a TEG SUPPLIER, I don't think is a problem.

I hope this help.

good luck
 
As Braek said MEG can be used for the dehydration of natural gas. However it has different equilibrium properties to TEG and therefore will not give the same dewpoint and a different design is required (contactor size, reboiler, circulation rate)

The consevatism in the design may allow you to use your system with MEG, BUT you need to seek advice from the designer / supplier
 
At the same purity, all glycols (MEG, DEG and TEG) have similar equilibrium dewpoints. However, you have to remember that the circulation rate required is based on the mols of Glycol vs. the mols of water and adjust accordingly. Also, the Glycol Reconcentrator operating temperature will change with each different Glycol due the boiling point required to acheive the same purity (you may need to use stripping gas or some other method to achieve the required concentration). The Glycol losses from both the Glycol Contactor and the Still Colum also change due to the Vapour Pressure of the Glycol used. At the Still Column, these vary from 1 to 2% for TEG to 2 to 4% for DEG to 6 to 8% for MEG. These chemical losses, as much as anything, determine that you should try to find a source of supply for TEG. However, in the interim, a properly adjusted MEG system may work, provided you are able to adjust all the appropriate factors with the equipment at hand.

G. Gordon Stewart, P.Eng.
Gas & Oil Process Engineering Consultant
ggstewar@telusplanet.net
 
Does any one have any information about memrane technology for natural gas dehydration?
 
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