Try simply pumps, the 600 series peristaltic pumps out about 2gph against 50 torr with a net inlet pressure available of 1psia. The more you increase the nipa the better it will perform.
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yes, but it makes retrivial of the resin faster and cleaner than removing the flask each time. This is especally true if you have silicone oil in your heat bath.
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The vacuum and preheater would serve the same purpose of matching the boiling point of the liquid to the feed temperature. You can either do this by reducing the pressure in the flask or by preheating the liquid before it enters the flask such that the vapor pressure of the liquid is the same as the pressure in the flask.
The interesting thing is that superheating the liquid with a preheater before it enters the rotovap doesnât do very much to increase your distillation rate, since the heat of vaporization is so high compared to the specific heat capacity. The same is true for trying to pull a super deep vacuum with crazy pumps and cold traps, it just doesnât really speed things up. For ethanol, the latent heat of vaporization is 575 kJ / L and the specific heat capacity is 1.9 kJ / L * c. This means that even if you could manage to superheat the feed stream by 10c, which would be pretty difficult, that would only buy you a 3.3% improvement in distillation rate.
The bottom line is, there arenât many tricks you can do to really improve the distillation rate of the rotovap besides just adding more heat into the bath. Depending on your available electricity, this could be a pretty straightforward thing to do by just adding more heating elements to the bath. You can buy these home water heater style coils for like 10 bucks on amazon. The rest of the electrical components wouldnât add up to very much.
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Awesome post, thanks
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Use a big cooler. Fill with warm/hot water.
Place mason jars with etoh wash inside. Thos will warm up the etoh wash, and be already warm when you suck it into your rotovap.
I had a spare big igloo cooler eyeballing me, i tried it and it worked pretty good.
Edit:
When i need to refill my 5l flask with room temp etoh wash, it literally takes -1.5 mins to get to flowing normally again. After i break vac to drain the recieving flask, it takes 45 seconds for the vac to go back to normal. BUT after 10x of doin g this, thats a total of 24.5 mins. Do that 2-3x and tour almost 1hr of down time.
I go my the numbers now. Whats the quickest, safest, and thurough way to do things now. Almost 8 yrs of 7day work weeks is tiresome for sure!
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The point of the preheater is just to prevent dumping a bunch of room temp, often much colder post winterization, solution into the BF. Which will stop the distillation until equilibrium is reached again.
No super heating, just making sure incoming solution is relatively close in temp to the boiling flask solution
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Yeah, -20 feed stream would definitely slow you down.
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Iâm no bizzybee, wonât catch me bending the laws of thermodynamics 
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Not sure if anyone else has done this, just I just found that the chinese RE series roto recovery ports can be attatched to a 2" triclamp fitting with very, very little effort.
broke my flask just now, and love finding solutions to problems quickly- this seems rather useful- triclamps are my legos now.
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So just hook it up to 2â tri clamp kegs and get much larger reviving flasks?
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youâll need some hoses and valves, but yes you can directly hook a 2" triclamp fitting to a chinese roto- just shave the gasket on one side.
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Put a T on your feed line and when you want to empty it just turn the valve or use the same feed line and have it hooked to a pump as lonf as your feed hose goes all the way to the bottom
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Get gamma buckets for survival and cut a whole in the top tou can get 30 gallon buckets so you will only have to put the hose in another bucket when itâs full
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Well done sir
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@Rowan How do you tell the keg (fantastic idea btw!) is full? Is there a cold-trap before the pump?
(We get 20 liters/hour recovery on all three of our 50 liter Rotos. @spdking. Just saying)
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How are you getting such fast recovery?!
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I donât run a cold trap anymore, just make sure the upper condenser isnât dripping - the half liter of ethanol I lose every other day or so if Iâm being aggressive with evap is not a big deal to me rn.
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I can tell when the keg is full after I put 15 gal through the unit. I can have my fab guy put a sight glass port on the top but as of now have not had any issues paying attention to how much ethanol goes in.
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That does, of course, makes sense. 