Recovery: Coils vs Tube and Shell

So I’m looking for some input from the community as to which would be best for recovery. We’ve been searching google and on here to Identify which would be best to use in recovery of a 70/30 butane/propane blend on a closed loop system that running 70# using a cmepol. Currently we are using a large recovery coil sitting in a 5gallon bucket of dry ice and iso.

We consume a lot of dry ice and because we run through a lot of dry ice that means a lot of co2 is sublimating in the lab and even with plenty of ventilation out of the lab and plenty of exhausting air out of the warehouse it’s always been a concern of built up co2. And of course there’s always the cost of a consumable like dry ice.

So we are looking for a solution to get rid of dry ice and go with a chiller and possible heat exchanger option. Do you have any suggestions? Or can you help point us in the right direction? Thank you in advance

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Co2 shouldn’t be a issue if you properly ventilate for butane. Both are heavy

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for the record, both of those options involve “heat exchangers”…tube and shells work great, but throwing the coil you have in an insulated vessel and running a chiller to it will work just fine.

to size your chiller you want to do some math. either match your heater, or figure out how many Btu you need to remove to get your desired recovery rate.

see: The ULTIMATE chiller calculator thread

do you have a flammable gas/LEL meter?
Get one for O2 content as well.

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Thank you for the correction in proper terminology. You are correct by tube and shell is what I meant.
Thank you for the link. I’ll do the math. I thought about throwing the coil in a insulated vessel like you’re talking about. Figured it would pretty do the same thing. Wasn’t too sure if one is more efficient than the next. Much appreciated for your response.

I would go with tube and shell rather than plate exchanger in this case, but I have to admit I don’t know why I hold that opinion. Something about easier to get the welds right because they’re visible is the best excuse I can give off the top of my head.

connecting what you have to a chiller may or may not be as efficient. it’s about surface area. you can pack more contact area into a smaller volume with tube and shell. more compact still with plate style heat exchangers.

for condensing your solvent post pump, all you really need is cold water.

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I ran 4-6 cmep’s off just ice water and tube n shell condensers and it worked great. I wasnt even cooling the recovery tank so that would be an added bonus if you were.

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Coils are generally higher “theta” than shell and tube heat exchangers, meaning they perform better at low approach temps. That being said, flow restriction is worse and footprint is miserable. Plate heat exchangers are fantastic although rarely perform well in sanitary applications (pain in the ass to clean). Both a plate and shell and tube will require pumping your slurry vs a coil that can just get stuck I’m a barrel, so there’s that. Unless you have a badass bath and tube (seems like the only fair description) unit like the ones @Soxhlet and @FicklePickle build.

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We (extraction community ) really need to start chilling in stages with multiple effects and recycling the energy that’s already available in the process

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Yep! No point in wasting those expensive -80C kilowatts on the initial hot solvent cooling. But often the increased system complexity requires bigger scale to be worthwhile. Challenge accepted

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I was looking at the Precision XMU The XMU Hydrocarbon Extraction System | Next-Gen Extraction - YouTube 11:08

Heat exchanger after mol sieve that uses the cold solvent on its way to collection to condense vapor on its way out. Makes a lot of sense to me. Do you think that’s just a shell and tube @cyclopath ?

Are any of you guys doing this? Recommendations for exchangers @killa12345?

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Bhogart has nice tube and shells and I believe both sides can take butane or propane. You can probably find one in the classifieds for cheap. People don’t know what they are worth lol

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can’t see how it could be anything else given the form factor and stated function.

I guess that could be a coil in a tube, but that seems like a dumb form factor for that trick.

I have a -80 40L i phase chiller for sale new off pallet

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