I’m confused by your statement. Tall and skinny allows more heated surface area and less vapor producing surface area. Short and fat provides more surface area for vapor production, and less surface area to be heated. Vapor production needs surface area. If you reduce the surface area, you reduce the amount of vapor you can produce with that vessel.
Pros and cons to both depending on your set up…
Yes im speaking on a passive system. There are several factors determining if you need coils or not. If you have bigger than a 2# system(passive) you probably need coils
I have 4 coils total. One is a pre-chiller to cool the butane as low as possible. Then I have a cooling coil connected to the jacketed recovery pot with another (internal) cooling coil. These are the ones that makes the negative pressure to recover all of the solvent. Then a heating coil in a sous vide bath on my jacketed collection to aid in recovery so i never chill my collection pot.
So for me if i had a tall and skinny collection pot it would get more surface area of heat and my solvent would distill more quickly, as long as the recovery pot stays cold. The surface area isnt just the collection pot its the headspace in the connected recovery pot which is way bigger (100#tank) and cold.
Take 2 pots filled with an equal amount of solvent, one short and fat and one tall and skinny. Now heat them with the same heating element and the tall and skinny one will have a much higher pressure faster than the short fat one. If your trying to recover solvent efficiently, passively - into a recovery pot then a tall and skinny collection (distillation) pot is the easiest way to it.
Thats why i only roll with my collection pot (short and fat) filled 10-20% when i can because if not i blow thru thr dry ice trying to condense what i just heated up
I’m going to read this a few times and wrap my head around it…its obviously more complicated that vapor producing surface area like I had thought
I only run passive. But I also only know from trial and error or what I’ve read on here. I strive for efficiency, so if I can learn how to recover more effectively I’m all ears. I run a tall skinny collection myself, be it small in the grand scheme of thing on here.
This isnt in relation to recovery vessel size and geometry correct? I understand how having a larger volume vessel, under vacuum, chilled, with more surface area to condense vapors into liquid is advantageous. I was specifically referring to collection dimensions.
If you have your collection heated to 90* tall and skinny, and another collection heated to 90* short and fat, and could maintain those temperatures, wouldn’t the short and fat collection distill more butane due to its larger vapor producing surface area? Given all other factors were the same?
Is the underlying issue, that you cannot properly heat a short fat collection to effectively distill the tane? So the larger vapor producing surface area isnt an advantage if it doesnt have the BTUs behind it to push the distillation? Just trying to confirm my uneducated understanding of it. Please correct it/me if I’m wrong.
What increases the vapor pressure of hydrocarbons etc in practical application is the temperature not the amount of headspace in a given volume. If that were the case a big huge collection pot would make its own pressure the bigger it got. I can assure you a tiny distillation pot with a heater attached will work much better than a huge distillation pot with the same heater attached.
For the same reason you dont want headspace in a diamond miner. For best results you fill it up all the way and then pressurize it to spec.
@TwistedStill Taller and more skinny equates to more pressure more push faster recovery . It just depends if you have a bottle neck in your system how fast you can recover . Shorter and fatter equates to easier distillation because of surface area but not as much psi or push so in return you recover more slowly . Its all about the psi how much pressure is pushing everything.
In reality were dealing with 2 very different curves.
1 for how fast the distillation vessel can heat up the solution to boil off the gas
1 for how fast the recovery vessel can cool down and condense the solvent from gas into liquid
I know i can cool my recovery vessel enough to alone make the solvent in the collection pot boil but its inefficient. If I add a little heat to the distillation pot and keep lots of cold on the recovery pot it distills (passively) probably 5-10 times faster than it does without using the heat.
So disregard vapor producing surface area of the vessel? That is somehow not a factor? Or it is a factor, just not as relevant as when evaporating hydrocarbons for fuel?
My scenario wasnt using the same heater. It was using the same constant temperature applied to the collection during recovery. Saying the butane in each collection, tall one and short one, were the same temperature. The btu of a heater isnt in question.
I believe yall are correct, just trying to further grasp it…
I think I’m just looking at it half backwards due to having some experience feeding equipment with propane and such. Feeding something with pressure and volume is different…I need to keep it that way in my mind.
You can distill at negative pressure or positive pressure. What it’s more important is the split, the difference in psi from the distillation pot to the recovery pot. If your recovery pot goes up in pressure (higher temperature) it will eventually stop the distillation from occurring in the distillation pot. You need to find the sweet spot for your system by adjusting the cold temperature (low pressure) in the recovery pot in relation to the high temperature (high pressure) in the distillation pot to achieve the highest rate of distillation. For me its keeping the recovery pot as close to -50°F as I can with the 2 coils and adding 75-80°F to the distillation pot via heating coil and jacket
So with my dumb ass appeased now…I have more ignorance to displace…
You all running coils passively…I was kinda under the impression people used coils for cooling injection, or in some form of running active(I dont know shit about that). Running 4 coils in that manner is pretty impressive. The only place I see the use for a coil in my application is injection, but I’m still able to get the solvent pretty cold with my small 10 lb tank.
I think running a dewax sleeve is probably a better investment at this point so I can cold soak if I desire. Like I said, previously…this is a hobby on a shoestring budget.
Thank you for the knowledge and insight 4200 fam
1 of my coils is an inline injection cooling coil like that. The other 3 + the jackets are for closed loop heat exchangers. One cold loop for recovery which has a coil dunked in dry ice slurry and a coil inside the recovery tank. The other warm loop with a coil in a sous vode bucket and a jacket around the collection pot and its base
For me passive means no recovery pump to move solvent via distillation. I still use bottled nitrogen and pumps to cool/heat my coils and jackets with. If you have a liquid pump that slows down the colder it gets thats a problem. You might not even notice it and have problems in the middle of runs and have to chase down the problem. More than once i have had to switch out the pumps on the coil loops in the middle of distillation because they went bad or failed completely. Still looking for the “ideal” pump for this application but i have gone thru several.
I’m familiar with the various states of heat exchangers. I play with heat exchangers/condensers on an industrial level…so I see it all to a certain extent.
I couldn’t apply a coil elsewhere without big bucks on jacketed vessels and an internal coil for the recovery vessel.
If ever
Draft beer coolers are often sold dirt cheap once broken they are supposed to be equipt with at least two and often 4 sscoils with 1/2 jic fittings
just need to rinse out the old beer 
It isn’t the coils that are costly. It’s getting a jacketed solvent tank, and a jacketed collection that are spendy for me. I’m a cheap fucker lol.
Introducing a injection coil would he pretty simple and cheap. Looks like I’ll see if I can find a broken beer cooler lol
That can also be done with a ss bucket or the polystyrene box and dry ice or dunkin warm water in an igloo depends how much effort you wan t to do 
Injection coils?
Yes…?
So your recovering through the coils into your vessel correct? So the heated collection creates vapor pressure, which is condensed in the 100 feet of coils. Once liquid, the solvent is then pushed into the solvent tank by the vapor pressure in the collection pot? That’s fucking sweet. I’d need to add some valves and fittings to get some bi directional coils for injection and recovery going…but I think thats the ticket.
[Propane Butane Mixture - Evaporation Pressure](http://Vapor Pressure of Butane/Propane/Mixes)
A good way to conceptualize all this is by understanding that the path from point A to B to C to D to E to F (A: Solvent Tank, B: Injection Coil, C: Material, D: Collection, E: Injection Coil, F: Solvent Tank) is basically a series of pressure drops that must be overcome by either an outside force (nitrogen) or by passively flowing from areas of high pressure to low pressure. The latter is done by understanding that temperature drives the pressure difference.
So, ultimately, you can increase your recovery speed by heating the collection hotter or by cooling the solvent tank lower or both.
Something else to consider, if your recovery injection coil is colder than your solvent tank, it’s just going to trap a ton of LPG in there.
My opinion is leave the recovery/collection vessel at room temp. Chill the solvent tank as low as possible, push with nitro out of solvent thru injection coil into collection and then purge nitrogen and begin heating recovery while maintaining ultra low on solvent tank.
As several people have mentioned, vessel geometry is huge, if I lived in a perfect world my recovery would be similar to a hexapod from bizzybee. Skinnier collection vessels that are gassed into super cold solvent vessels and then manifolded into the bulk solvent tank.
Exactly!
Yeah, once I used this setup, I won’t go back. Even my small setup runs a lot better with a coil in it.
A coil and a sous vide cooker are great for recovery.