Crude Wax Suspension by Mixing in API tankage

[MidstreamEgr]

I have an oilfield project, where the crude has a realtively high wax content (5%-30%). I am looking for a way to keep the wax from dropping out while in tank storage and piping to loadout (to rail and truck).

I have been reading about eductors (NciWeb.net/tank.htm) and heating systems. I like the idea of educotrs, since i want to keep the BS&W in suspension as well (kill two birds...), but not sure if just "mixing" the tank will be sufficient to avoid paraffin deposision in tank bottom. Basically, will just maintaining 1 tank turn per hour be sufficient to avoid deposition? Or do i need to add heat to keep it avoid wax appearance temp (and related safety features for heating crude...)

I assume I'll need to heat trace the lines to maintain the piping above wax appearance temp regardless (since the lines are run intermittently for loading, etc), but again maybe fluid velocity will "clean" the lines to avoid buildup?

 

[geesamand]

Will mixers be sufficient to keep the solid wax particulate in suspension? - Yes absolutely assuming the mixers are sized accurately and there are enough manways/nozzles to give the mixers access to the full tank floor. Take care with side entry mixers that not all are created equal and there can be a huge difference in real-world efficiency.

Will mixers keep the wax from solidifying? That I don't know. Based on what you're saying, the wax solidifies when the temps drop too low. If you have a heat source then the mixer will certainly help avoid cold spots and solidification there.

I don't have experience with eductors, but clearly they can only affect what's local to that device. A side-entry mixer on a swivel mount can be cycled through different orientations so that no part of the tank floor is left to build up.

 

[geesamand]

I asked my process expert about these eductors. He did offer that if you're going to use them, upsize the pump adequately to get the necessary flow velocity through the eductor. Also make sure the eductor service life vs. erosion is acceptable for your maintenance plans.

The location of the eductors will have to be carefully oriented to generate motion throughout the whole tank.

David

 

[MidstreamEgr]

Geesamand, thanks for the feedback!