Distilling propane Question, Active Recovery

Hi guys,
Very new to the Closed Loop game in Canada,
First system is mere days away from delivery, I’ve done a ton of research on operation, however I’ve found it hard to find valuable info, or info in layman’s terms - on propane (single solvent) distillation and active recovery, and I want to make sure I have all the proper info before attempting to run some fire ass nugs into pho, or worst case scenario a pile of goop. I have the 6" OSS ‘St.Helen’s’ unit on the way, with ptfe gaskets all around, 300psi tank gauge, and 300psi PRV for tank, as well as sleeved column.
My question is; what temperature should my water bath be at for recovering the pane, while keeping my pressure low, and holding off longer chain residuals ( I know that a DI / Iso slurry brings me down to around -110f and a ice water bath is around 32f) is -110f too cold to get rid of residual pentane and leave the mystery oil? If so how do I find a happy medium?

No roasting? Like a propane fired BBQ?

Assuming Passive. [edit: wish I could read! you explicitly state active. drop the warm side a bit and just make like you’re running product]

You’re not trying to boil off the longer chains. They have a HIGHER boiling point than your solvent of choice.

you need one bath slightly above the boiling point (-42C), and one well below.

Dry ice/Ispropanol should work well for the cold side.

For the warm side, there are a slew of options here…

Ice + NaCl will get you -20C, but I imagine a hair colder would be ideal.
Maybe ice & calcium chloride hexahydrate?

You vac your system down, load the solvent into your receiver, and use the column as a reflux head (so you want to chill the column to -40C too). You chill the hell out of the working tank, & it acts as the condenser.

All the bad players are left in the splatter platter where the good stuff usually appears.

Skunkpharm has a decent writeup of the process for n-butane. although you’ll need to translate things like valve numbers to match your rig

caveate: I haven’t performed this particular trick, as my rig is only certified for a 30/70 mix & I’ve only ever run n-butane in it.

Manual should have this in it too…

…nah more like a volcano.

I apologize for the typos and lack of info, I meant to step back and edit but got sidetracked, Yes hold back not boil off, (I know my terminology isn’t up to snuff) I’m wondering if simply having my collection pot surrounded in dry ice would be enough to condense the garbage and keep my pressure low enough to stay in the green zone throughout recovery, with coil and 25# stainless tank in DI/Iso, ideally I’d like to not exceed 50psi in my vessel. I also only plan to distill/store enough solvent in my SS tank to do a few runs/week , then I can repeat the process with my supply tank when needed.
*** pump is a trs21 ( had no choice, will grab cmep after a few runs if the fucker doesn’t shit the bed before that)

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if collection pot is held below -42C, you should have very low/zero vapour pressure. and will have to work the pump to make it move.

At -20C you should see about 20PSI Propane - Vapor Pressure vs. Temperature

Using a pump will allow you to pull a vac on the collection pot and reload. Assuming you have room in your storage tank. You don’t want to go aver 80% full. So use a scale when loading your collection pot.

Do you have molecular sieve in-line? You should. Otherwise you’ll pick up water…

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