Recovering into half full tank?

I want to buy a bigger solvent tank, a 50lber. I usually use only 20lb of solvent at the most per run. Everything I’ve seen online about running a cls says to pull a vacuum on the recovery tank, but if my solvent tank is my recovery tank, can I just recover the 20lbs of solvent into the tank with the remaining 30lbs?

Thanks in advance!

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Yes get solvent tank cold enough and it will start to pull vacuum on itself

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Make sure tank holds 50# @ 80% fill though

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I always have it covered with dry ice, so that should be good then. Will recovery be slower than with an empty tank tho?

And definitely, I will be buying it with the 50# in it already so I’d hope they figured that out already :rofl:

Maybe a bit slower but it shouldnt be in all reality.
As stated of cold enough it will be under vacuum so no pressure to stop the flow.
Expect to use way more dry ice. I stopped doing passive when i moved to a 50lber. Di started costing more then a recovery pump

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Why not just use the entire tank each run? A higher gas:material ratio won’t hurt anything.

My system is built for a 5 lbs with a 10:1 ratio. Even if I run 2lbs I still use all my solvent.

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I use a 50 lb stainless tank for my passive system.

How much di were you Having to use per run?

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I cant remember it’s been a long time.
Id use 100# for 2 5# runs when i was on a 25lb tank.
So more then that. Cany remember figures but do remember doing math and calculating running a cmep was cheaper over a small period of time vs passive

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That must suck when you want to do multiple runs. I hardly ever run the entire tank unless i have to.
How much dry ice do you use to recover 50lbs on your setup? Do you use a coil?

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@Slabby It takes me 25 minutes to recover all my gas. While it’s recovering I repack my column and get ready for next run. I have dual 1/2” recovery lines, each one has a coil. I use 50# of dry ice for a single run and it takes 15lbs of additional dry ice per run after the system has initially been cooled.

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Wow thats impressive. 2lb a min?!
Post a pic!
What do you have your tank in?
At that rate id be dumping the whole tank also

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Coils are in dry ice acetone
Tank is in dry ice denatured alcohol

This was a few sessions ago. I am using a little bit l smaller container for my solvent tank now (helping even more with dry ice consumption)

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Wow ok. Thats insane. Ive never seen that fast using dry ice but a slurry makes sense

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@Slabby

I am using a propane/iso blend. It speeds things up a bunch.

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I run 40 40 20. But never the way yoir setup. Makes me what to change some shit to try this.
I have a sleeved tank on its way so i can run a slurry in the open jacket

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Do you fill your headspace on your tank with n2 to inject solvent?

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@Slabby
Yeah, my system wouldn’t even be able to move solvent without nitrogen. I start chilling my solvent tank during set up, so it is already down to 0psi when it’s time to inject. I charge the headspace to 30-40psi initially and then up the psi until I achieve my desired flow rate into collection.

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What do you do if you use n2 assisted injection?

@Unicorn_Theory1 Vac out nitrogen before recovering?

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