Hey gang, first post here so I’m really hoping I found the right thread to post this in. If not please feel free to redirect me to the proper place.
Im trying to find a way to recover about 200gal of ethanol in a single day with this setup.
Left to right: I have a still with an air operated agitator in it, 4inx24 in condenser, into a smaller chilled tank, then over to a larger chilled storage tank. I’m running a single small diaphragm vacuum pump to assist.
Chillers:
Touch Science DLSB-50/80 on the condenser AND final large ethanol storage tank.
MTA TAEevo Tech 031 on the small tank after the condenser.
The problem I am having is the distillation rate seems to have dramatic peaks and troughs, to the point where my condenser is filling with ethanol. I think its just building enough pressure to push itself all the way over the large tank.
Maybe this is just a stupid setup altogether? Or maybe there is just something Im missing here. Any insight is greatly appreciated.
This distance from the hot side to the cold side is to far to start with. me personally I would come off of the hot side with 3 45 degree elbows into the condenser then into the recovery tank. after that its just math for btu’s.
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Three 45 degree elbows? Im sure Im just missing something but wouldn’t that mean I’m heading back toward the still/hot side? Or is one of those 45’s supposed to be like horizontal with the ground?
Im dumb. Sorry. I understand the difference between a 45 and a 90 haha my bad.
the 3 45’s are just for adjustability to change the pitch of the condenser. your want that condenser to be at about a 45 degree angle. angles not terribly important it just needs to have enough downward draft to flow the fluid. you want the shortest possible distance between the hot side and the condenser (cold side).
btu calculation for GPH of ethanol phase change is 385x6.59x200/how many hours you plan to run. this doesnt account for rise in temp btu’s needed but just add 20% and you should be pretty close.
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So if I want to recover 200gal in 8 hours I need 75k BTU or kW rating right?
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yes on BTU’s or it would take 22kw. 3.42 btu’s per watt.
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Researched a bit and got the kW rating to BTU per hour conversion rate. Thanks so much for your help man.
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your welcome man. Have fun!
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Just a fun update. I adjusted some stuff today because of what you told me earlier. Here is a new pic of what it looks like.
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The cooling power of your chillers is:
MTA TaeEvo 031 = 9.1kW @ 7C
DSLB-50/80 = 4.8kW @ 0C
The condensing temperature of Ethanol is 78C
The heat capacity of ethanol is ~ 2.5 kJ/kg*K
The latent heat of ethanol is ~ 850 kJ/kg
Assume an 8hr workday = 28,800 seconds
200 gal of Ethanol is equivalent to about 600kg of ethanol.
So…you need to condense and cool at a rate of 600kg/28,800 = 0.02kg/s
The size of the chiller needed to keep up with condensation at this rate is equal to:
Power of Condensing Cooler = (0.02kg/s)*(850kJ/kg) = 17kJ/s = 17 kW
@ 80% efficiency = 21.25 kW
The size of the chiller needed to chill the solvent to desired temperature (I’m assuming -40C) is calculated as:
Power of Chiller = (0.02kg/s)(2.5kJ/kgK)*(78C-(-40C) = 6kJ/s = 6kW
@80% efficiency = 7.5kW
In short, both chillers are too small if we adjust for actual thermal efficiency—however you can improve in a few ways;
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the MTA should be hooked to the condenser and the DSLB should be hooked to the tank. As you can see from calculations, the cooling load required for condensation is 3x as large as the cooling load for chilling. So use the larger chiller on the condenser and the smaller on the tank.
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extend your work day to a 24-hour shift after making the switch in step 1 and the chillers you have will work just fine.
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Insulate. As it sits currently, the thermal efficiency of the system is easily below 80%—this means you must divide the calculate numbers by 0.8 to see the ACTUAL chilling load. Insulation bumps this efficiency up more than you’d think.
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Buy appropriately sized chillers for the job of 200gal/day is absolutely required.
-Phil
Edit: I realized you said 8-hours so I adjusted accordingly.
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use a radiator and do most of your first stage condensation at ambient
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My god you guys are amazing help. Thank you. Thank you. Thank you.
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Sweet still @ChillinDistillin. Welcome to future4200
@downtheterphole do you know of any stainless radiators you can link me to?
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well…since you asked.
if those heating elements are going directly into your “starts at 190, ends as crude”, then one might want to question your sanity, and the placement of your agitator… and even your use of a flat bottomed vessel.
I personally would not put heating elements in direct contact with 190proof solvent (certainly known folks who do it. I just don’t recommend it). Bane Marie or jacketed vessels that keep the elements out of the hi-test are safer. I prefer conical vessels for my pot stills, because they deliver the product out the bottom way more effectively than flat bottomed vessels.
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if you circulate your cooling water through the radiator rather than your solvent you don’t need a stainless radiator.
@tweedledew may have pictures of his set up around. I used that strategy with “Maria”.
Who is king of EToH Recovery? - #109 by cyclopath
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The elements go into a water filled jacketed wall around the still. They never come in direct contact with the processing fluid aka crude.
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awesome! that makes the agitator easier to understand too. 
glad you had that part covered, with luck it’s now covered for a bunch more folk too.
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I am left wondering, in terms of insulation, what types of material do you suggest? And what is worth insulating?
My first guess would be, let the chiller run over night, anywhere that ice builds up is a perfect place to insulate right?
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