Salt removal from rich MEG

[MMcLean]

We are doing some work for a client, converting an existing TEG regen unit to MEG service. Due to the salinity of the produced water, the Rich MEG to be processed has a high salt content (of the order of 12,000 ppm TDS). The concern is that the salt will deposit on the tubes of the reboiler tube bundle as the water evaporates and result in scale fouling. The reboiler has not been designed to be pulled apart easily for cleaning, due to the elevation and the small area between the tubes. Does anyone know of a cost effective method for reducing the salinity of a rich MEG stream that could be applied upstream of the reboiler.

Thanks

Mark

 

[MortenA]

How can there be salt in the water in the gas phase - or are you recovering MEG from produced water added to prevent hydrates and such?

best regards

Morten

 

[TexasPE]

Salt removal generally requires vaccum distillation. A proprietary process has been developed by CCR (Canadian Chemical Refining)to deal with the problem. They have offices in Calgary and Houston. As the other response noted, water removed from gas phase should not contain any salt. Either you have a carryover problem which might be solved with a good inlet filter separator to the contactor or you are contacting the full wellstream prior to separation. In the latter case, your client should look into the CCR process. Kvaerner and Shell both have a similar process as well. Some clients have believed that they could operate without the salt removal cycle but experience has shown that it leads to deposition in the gathering system, separator dump valves, plugging of flow lines, and severe corrosion and plugging in the reboiler, etc.

 

[MMcLean]

Thanks guys

I have also been looking into High Efficiency Electrodialysis (HEED) that a compnay called EET Corp (

http://www.eetcorp.com)has.

They claim it is more cost effective than Vac distillation, ion exchange or RO.