4 replies to this topic

[Motrack]

Hi Folks,

 

I'm looking for some options. We have a NGL stream that is treated (liquid treating) with Amine and exits the facility. This does not always meet the NGL spec which says no free water at 34 F (tested by observation in a separator). We need to remove the water (15 ppm free water at 60 deg F) prior to the fence line. One path in consideration is using a mole sieve unit (expensive). Another option is moving to inlet treating (also expensive). I'm looking at other options like a refrig unit to chill the NGLs to 25 F in order to drop the water out. However, this requires using a hydrate suppressor like methanol or ethylene glycol. Injecting methanol also means possibly using a water wash, that puts us back where we started. Removing ethylene glycol is difficult (I hear) and may be done by fractionation. Is this true? My simulator shows me that ethylene glycol and water "fall out" at 25 deg F in a separator. Any input regarding your experience in the matter or other options that exist would be great.

 

Thanks

Motrack

Edited by Motrack, 17 January 2018 - 10:50 AM.

[Bobby Strain]

NGL can be a mixture of many things. So, you need to be more specific about composition.

 

Bobby

[Motrack]

Hi Bobby,

 

This stream is about 55% C2, 28% C3, 12% C4, 4% C5, 1% C6, 

 

Thanks,

Motrack

[Bobby Strain]

Your situation is a rare one. I presume that you are treating NGL at the site where they are recovered in a low temperature NGL recovery unit. Most operations send the dry NGL stream onward without further treatment. Then any treatment is located at the NGL fractionator site. So you may be limited to one alternative: mol sieve dehydrators. You might take a look at using mol sieves to remove the sulfur compounds instead of amine solution. With this processing, the stream would not be exposed to water after recovery.

 

Bobby

[Motrack]

Thank you Bobby.