reflux - continuous operation still

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parkland
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reflux - continuous operation still

Post by parkland »

Hi all,

So I have read some fundamentals, and looked at several designs.
What my goal really is, is to make a continuous run reflux type system.
That is, heating the wash, using an upper secondary part to partially cool and condense contaminates, and a final condenser.

My first thoughts are using a 1.25" copper pipe with band heaters, and the bottom is drained off slowly.
On top as a reflux condenser, I was thinking about a coil of pipe inside a bucket with the water being temperature controlled.
Maybe 50 feet of tubing. Would open tubing work fine like this because of the large surface area? Or still require packing?

I obviously know most reflux stills are larger diameter, I would think that height can overcome that limitation but not sure how much.
I would think any similar design would work theoretically but quality and speed affect the design.
It does make sense to me from other projects that a long tube immersed in temperature controlled water will function well as a condenser.

I suppose the part I'm most curious about is a skinny 1.25" heater column; if the ethanol can boil out or if it will stay mixed and not boil off
before ending up in the trash.
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still_stirrin
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Re: reflux - continuous operation still

Post by still_stirrin »

This from the “Continuous Stripping Stills” forum:
We don’t condone the use of Continuous Stripping stills as a method of running 24/7 as this is a commercial setup only.

Home distillers should never leave any still run unattended and Continuous strippers should not be operated for longer periods than a Batch stripping session would typically be run to minimise operator fatigue.


Look for any correspondence regarding such in that forum. But, you’re kinda’ overstepping our rules here.
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LWTCS
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Re: reflux - continuous operation still

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parkland wrote: Fri Jan 15, 2021 4:28 pm Hi all,

So I have read some fundamentals, and looked at several designs.
What my goal really is, is to make a continuous run reflux type system.
That is, heating the wash, using an upper secondary part to partially cool and condense contaminates, and a final condenser.

My first thoughts are using a 1.25" copper pipe with band heaters, and the bottom is drained off slowly.
On top as a reflux condenser, I was thinking about a coil of pipe inside a bucket with the water being temperature controlled.
Maybe 50 feet of tubing. Would open tubing work fine like this because of the large surface area? Or still require packing?

I obviously know most reflux stills are larger diameter, I would think that height can overcome that limitation but not sure how much.
I would think any similar design would work theoretically but quality and speed affect the design.
It does make sense to me from other projects that a long tube immersed in temperature controlled water will function well as a condenser.

I suppose the part I'm most curious about is a skinny 1.25" heater column; if the ethanol can boil out or if it will stay mixed and not boil off
before ending up in the trash.
Are you able to put together and post a diagram ?
Trample the injured and hurdle the dead.
parkland
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Re: reflux - continuous operation still

Post by parkland »

still_stirrin wrote: Fri Jan 15, 2021 7:36 pm This from the “Continuous Stripping Stills” forum:
We don’t condone the use of Continuous Stripping stills as a method of running 24/7 as this is a commercial setup only.

Home distillers should never leave any still run unattended and Continuous strippers should not be operated for longer periods than a Batch stripping session would typically be run to minimise operator fatigue.


Look for any correspondence regarding such in that forum. But, you’re kinda’ overstepping our rules here.
ss
OK, obviously I don't want to overstep rules, but why would a continuous run device only be for commercial use?
I'd have no intention of running it unattended, I do think a continuous run system would be better to set up for a high quality distillation as the product and byproduct could be recycled back into the sugar wash for a while while temperatures are adjusted and then start collecting the product once everything is running ideal :think:
parkland
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Re: reflux - continuous operation still

Post by parkland »

20210116_222947.jpg
This is what i was proposing;

The pipe would have an overflow from the bottom to control the fluid level.
The pipe would be heated with clamp heaters and electronic controls.
I already have a waste oil boiler I made that I have running at 72-75*C so I'd preheat the sugar wash using that, so the electric heat would not need to raise the temperature much.
The condenser heads I was thinking could be fairly identical in design, but obviously operate totally different temperatures.
The condensers could be made from maybe a pail with tubing coiled inside, then circulate water through the pail, and have a radiator connected to that coolant loop, with a temperature controller to operate a fan to regulate the cooling water temperature.
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Re: reflux - continuous operation still

Post by parkland »

A huge benefit of this would be that the pipe would take minimal space and the condensing heads could sit in the garage rafters, not taking up space.
I know in theory it should work, but given the narrow pipe and narrow tubing in the cooling heads, I'm curious how well it would work.
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Re: reflux - continuous operation still

Post by Yummyrum »

Have a look at some of the continuous strippers in the Continuous stripper section.

https://homedistiller.org/forum/viewforum.php?f=109

I think you have a very very fundamental idea but you are missing all the detail .

Yes , you can pump wash into the top of a column and alcohol will come out the top and alcohol depleted wash will exit the bottom . The column however must have packing or plates so that there is a place / surface / medium fir the alcohol to flash and raise up the column and become separated from the water .... and hopefully the tails alcohol if that is part of the Goal . You can’t simply pump it onto an element and use a Deflagmator regardless of how you fiddle temps ... without packing or plates you will not achieve any separation worth mentioning

As you pictured , an element or heat source ... maybe a steam generator needs to supply energy at the bottom of the column to allow the flashing of alcohol up the column . .... but you need packing or plates

Now consider all that flashed off alcohol , it won’t just be ethanol , but also all the heads and foreshot products as well .... and if you are efficient enough , also all the tails products .

So you then need to batch distill all that collected alcohol to seperate out the drinkable stuff ..... or if you have managed to get the stripper working successfully , feed it into a second rectifier column that can remove all the fores and head towards the top and tap off the good stuff further down .

Commercial distillers like Jack Daniels or Bundaburg Rum use these big continuous strippers and then Batch distill the stripped wash in Pot stills to remove the heads .

Places like Bacardi have Multi column continuous stills that just just pump out high proof hearts day in day out .
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Re: reflux - continuous operation still

Post by parkland »

I will read that section. I had not come across it yet. but I have been doing lots of reading.
The packing, Not that I'm ignoring it, but was leaning towards it can be eliminated by more surface area, but I may be wrong.

From what I collected so far, a pot still produces the acetone, methanol and ethyl acetate and then the ethanol, at which point the temperature may need to be raised to get the rest of the ethanol as it's boiling point is higher being mixed with water.

The design I sketched out, the column would be heated with several clamp heaters and probes, likely set close to 100*C.
The first condenser head would condense all the heads and they drip back down. If there was 50-75ft of pipe submersed in temperature controlled water I would think the vapour would have plenty of time to condense without packing. (could be wrong).
However, if the heaters are set to say 98*C, there should be only foreshots or heads and the tails shouldn't boil off.
I don't think I'm really forgetting details just re imagining a setup using a column as a boiler and a heat exchanger as a reflux function, and another heat exchanger as a condenser.

Maybe... this would be a better device to use for boiling the alcohols from the wash, and use a secondary step to separate the ethanol from other products after.
Still have a lot to read....
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Re: reflux - continuous operation still

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parkland wrote: Sun Jan 17, 2021 12:01 am From what I collected so far, a pot still produces the acetone, methanol and ethyl acetate and then the ethanol, at which point the temperature may need to be raised to get the rest of the ethanol as it's boiling point is higher being mixed with water.
That sounds like the magic boiling point myth. The bad news is that the actual science is a lot more complicated than the myth, so don't base your design on the myth.
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Re: reflux - continuous operation still

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I feel like your current iteration will be sending quite a bit of alcohol down the drain. Or, you will need so much more power to ensure that all of your alcohol flashes in a timely manner.
Using your beer as cooling medium for knocking down your alcoholic vapor will help save on power requirements.
Will it make vapor? I assume so.
Will it do its job well? I'm doubtful.

You'll want your beer injection temps as close to 78° C as possible.
We (couple fellas here) helped to determine that 408 watts, per gallon, per hour is what is needed for power.
Since we sorta hammered that out with napkin math, I wasn't too sure how much heat losses would affect that calculation? I was worried that perhaps 500 watts would be a safer bet.
As it turns out 408 works really well and room to spare on a well designed system.
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parkland
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Re: reflux - continuous operation still

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RE : sending alcohol down the drain;
Of course anyone would want to avoid this. So one way I was thinking to avoid this in the boiling column is to use gradient adjusted heating based on the column height., As a rough explanation if the boil column is about 6 ft high, and there are 4 band heaters, the top may be set at 99*C, the second 101*, 3rd 102*, 4th 103*, as the fluid at the bottom of the column would have higher boiling points. Otherwise whatever alcohol didn't flash boil of the top would end up in the waste. (I'm stating close to water boiling temperature, less may be desirable to produce cleaner product.)
I realize a skinny tall column to boil wash is slightly unconventional, but it might work well for keeping spent product from sticking around.

By beer injection, I'm assuming this means the sugar wash injection. I have a 140,000 btu boiler used for heating my garage and house, it runs 72-75*C so I was planning to use that for pre heating the wash before entering the boiling column, and let the electric heaters bring the heat up from there. I could add an electric pre heater to control the incoming wash temperature and bring it from 72 to 75 to an even 78. I'm assuming the 408 watts per gallon per hour figure is from room temperature 20*C or so.



RE: Boiling point myth;
Yes, this was and is still a difficult thing to learn. My experience so far is limited to boiling mash out of a pot inside a larger pot in water on an electric element to prevent hot spots. In fact I remember thinking I could increase temperature to 77.5 and collect the junk, then let it sit at 78 and collect pure product. Too bad it doesn't work that way haha. I have played with oil gasification before so I am a little familiar with heating and condensing to fractional distil fluids, but that isn't a product that you drink so a little less dangerous. Or more dangerous if were worried about fire lol.

Side question; I notice cooling water for product condensing is always said to be "as cool as possible", frequently using running tap water (10*C) or ice water. Since ethanol condenses far warmer than those temperatures, is the cool water just to make sure the product condenses in a short tube with little surface area? or is there a science reason for actually bringing it down that cool?
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Re: reflux - continuous operation still

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parkland wrote: Sun Jan 17, 2021 11:25 am Side question; I notice cooling water for product condensing is always said to be "as cool as possible", frequently using running tap water (10*C) or ice water. Since ethanol condenses far warmer than those temperatures, is the cool water just to make sure the product condenses in a short tube with little surface area? or is there a science reason for actually bringing it down that cool?
You don't have to believe everything you find on forums and Youtube. If you've made the mistake of building an undersized condenser, you have to deal with it the best way you can. My product condensers are large enough that I can switch the water on and off with a thermostat to maintain a desired condensate temperature range while minimizing my water use.
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Re: reflux - continuous operation still

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NZChris wrote: Sun Jan 17, 2021 11:39 am
parkland wrote: Sun Jan 17, 2021 11:25 am Side question; I notice cooling water for product condensing is always said to be "as cool as possible", frequently using running tap water (10*C) or ice water. Since ethanol condenses far warmer than those temperatures, is the cool water just to make sure the product condenses in a short tube with little surface area? or is there a science reason for actually bringing it down that cool?
You don't have to believe everything you find on forums and Youtube. If you've made the mistake of building an undersized condenser, you have to deal with it the best way you can. My product condensers are large enough that I can switch the water on and off with a thermostat to maintain a desired condensate temperature range while minimizing my water use.
Do you feel that condensing at warmer temperatures can help with a cleaner product? or is it just to save water?

I know I won't always believe everything I see, but I have to believe there are methods that are tried and true by people that know more than I do. haha
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Re: reflux - continuous operation still

Post by NZChris »

Once the condensate is going downhill, everything in it will go into the receiver unless you have done something silly and dangerous and have vapor coming out of the condenser.
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Re: reflux - continuous operation still

Post by parkland »

NZChris wrote: Sun Jan 17, 2021 12:22 pm Once the condensate is going downhill, everything in it will go into the receiver unless you have done something silly and dangerous and have vapor coming out of the condenser.
Right. I suppose in theory the reflux head or first condenser would put anything lower than the ethanol boiling point back into the boiler. Was just thinking there are a few compounds with close to the same boiling point as ethanol so maybe it would work to have the condensing head operate at a temperature where the ethanol is condensing but other compounds remain in a vapour state, to be condensed by another unit and drain to the garbage.
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Re: reflux - continuous operation still

Post by NZChris »

That's the magic boiling point myth again.
parkland
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Re: reflux - continuous operation still

Post by parkland »

NZChris wrote: Sun Jan 17, 2021 1:16 pm That's the magic boiling point myth again.
I must like that myth lol. Darnit.

Now I'm reading about silica to remove water from methanol :wtf:
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Re: reflux - continuous operation still

Post by Corsaire »

To put it bluntly: seems like you don't have a clue how distilling works

Your drawing shows a rather poor rendition of a continuous stripper.
If you don't intend to use heat exchangers I'd use batch distillation, like the vast majority of us homegamers. Add a preheater if you like.
Your napkin drawing has no provisions to separate heads from hearts and tails. So research how the big boys do it or just go batch.

Also. Hard to remove methanol if there's hardly any present.

Ever wonder why the big outfits always run multiple columns? Would be a lot cheaper if your design worked.

Not meant to discourage you, just do some more studying now, it will save you a lot of frustration later on
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Re: reflux - continuous operation still

Post by LWTCS »

That is an interesting bit of remedial reading. Not really practical for spirits production.
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parkland
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Re: reflux - continuous operation still

Post by parkland »

Sorry maybe it wasn't a good drawing but there is heat exchangers, the first reflux stage and a product condenser.

The idea was to coil pipe in water so that there might be 50 feet of pipe without 50 feet of actual height.
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