Actually running a stripping (continuous?) still

[therealraycharles]

How do you actually run one of these? A couple of questions for those of you who actually run these stills (manu, violentblue, absinthe, etal):

1) The way I understand it there needs to be a balance between how much steam goes in the bottom and how much wash comes in the top. This is because the heat from the steam is transferred to the lower BP ethanol in the wash right? How hard is this to control? Do you find it is best to adjust the rate of the wash, the rate of the steam, or both?

2) Are there any distinct advantages over using the spent wash (with an initial water charge) in a boiler VS steam injection ("wasting" the spent wash) ?

3) What sort of "observables" do you have? Are you monitoring anything like the ABV in the "spent" wash, temperature at a specific point in the column, output ABV, etc

Some these are touched on briefly in the other posts which consider continuous stripping, but I'm interested in finding a little more before I spend some big money on a column (since I'm not interested in neutral, I haven't built one to experiment with...)


* Yes, I already know that there will be heads and tails and foreshots and there are no cuts. I can handle it. No discussion or warnings are necessary *

[rad14701]

(since I'm not interested in neutral, I haven't built one to experiment with...)

What, exactly, are you after then...??? What comes out will be neutral spirits, with foreshots, heads, and tails... Virtually all flavor normally carried over in a pot still will be stripped...

[MuleKicker]

Yes, I already know that there will be heads and tails and foreshots and there are no cuts. I can handle it.

[Bayou-Ruler]

Yes, I already know that there will be heads and tails and foreshots and there are no cuts. I can handle it.

lol.....

[airhill]

I fail to see what the confusion is. The title of the thread is a stripping still, what is likely to come out is a low wine with the flavour carried through. The choices then are to potstill it for a flavoured drink or run it through a column for a neutral, making appropriate cuts (unless this is to be used as fuel )
I'm afraid you will have to wait on Manu or one of the others with experience to answer your questions

[olddog]

Are we talking about a stripping still or a continuous still, a continuous still is a production still and has no place in home distilling except for fuel production, and even then licences are required.


OD

[airhill]

I'm afraid I disagree with that OD and its probably the terminology.
The only difference between a batch load still and a continuous run still is the amount of wash heated at a point in time; the amount stripped could be the same.
As the person who asked the question was talking about steam as an energy source it makes more sense to use a continuous run still.

[MuleKicker]

what is the point of running a continuous still if you aint interested in running large volumes?

[therealraycharles]

(since I'm not interested in neutral, I haven't built one to experiment with...)

What, exactly, are you after then...??? What comes out will be neutral spirits, with foreshots, heads, and tails... Virtually all flavor normally carried over in a pot still will be stripped...

I was under the impression that flavor would come through if you fed from the right point to prevent reflux.

Yes, I already know that there will be heads and tails and foreshots and there are no cuts. I can handle it.

lol.....

Obviously I plan to do a spirit run in my batch still after the strip so I can make the cuts. Every other thread just had 120 posts about how you can't make cuts in a single column continuous rig and everyone in the world would surely die if you ever dared to do any distilling without making cuts. I was trying to "cut" to the chase, so to speak.

As for terminology, I interpreted that "continuous" just meant I could feed the mash in as long there was mash to feed, so I didn't have to heat up 60L washes all at once (since I don't have a 60L pot, or a wish to do 3 20L runs), and that a continuous still that didn't make cuts was for stripping only, and therefore a "stripping still".

I'm interested in reducing the labor required to make it to a spirit run, as well as the energy input required to get the thing going.

[kiwistiller]

what is the point of running a continuous still if you aint interested in running large volumes?

For
a) fun, and
b) energy efficency with pre-heaters and whatnot.

You might want to PM the guys who have experience with continuous and draw their attention to this post. Most of them aren't around here much.

[airhill]

I promised myself I would not do this again, however just for fun
A completely untested untried design for a continuous stripper (note this has not been completely thought out )

[manu de hanoi]

How do you actually run one of these? A couple of questions for those of you who actually run these stills (manu, violentblue, absinthe, etal):

1) The way I understand it there needs to be a balance between how much steam goes in the bottom and how much wash comes in the top. This is because the heat from the steam is transferred to the lower BP ethanol in the wash right? How hard is this to control? Do you find it is best to adjust the rate of the wash, the rate of the steam, or both?

2) Are there any distinct advantages over using the spent wash (with an initial water charge) in a boiler VS steam injection ("wasting" the spent wash) ?

3) What sort of "observables" do you have? Are you monitoring anything like the ABV in the "spent" wash, temperature at a specific point in the column, output ABV, etc

Some these are touched on briefly in the other posts which consider continuous stripping, but I'm interested in finding a little more before I spend some big money on a column (since I'm not interested in neutral, I haven't built one to experiment with...)


* Yes, I already know that there will be heads and tails and foreshots and there are no cuts. I can handle it. No discussion or warnings are necessary *

1) you control the wash feed to get the best of the available power. Too much wash and you get first ethanol in spent wash then slower product output.

2) steam injection tastes better. Spent wash can be used to pre heat the fresh wash

3) You monitor the temp at the bottom of the stripper and make sure it doesnt go below 100C (if so you are loosing ethanol in the spent wash). Just increase the wash feed slowly until that temp start dropping, then decrease wash feed to go back to 100. And that's it your stripper is set. But you still have to control that your wash feed doesnt change.

[jdpete]

How much increase in efficiency can you expect from using the spent wash to preheat feed?

Jeff

[manu de hanoi]

How much increase in efficiency can you expect from using the spent wash to preheat feed?

Jeff

about 15% if heating directly
about 25 % if injecting steam

[RefluxFan]

what is the point of running a continuous still if you aint interested in running large volumes?

It is very helpful for the person that doesn't have alot of time to do full on stripping and final runs,ie: 1 hour here, 20 mins there.
You don't have to heat the whole batch at a time, just feed the continuous at a small constant rate and strip until you are ready to shut down until next time. Easy.

Obviuosly the spirit run would have to be a batch run, 'coz you can carbon filter heads and tails until it tastes like the best Vodka in the world, but it'll still kick your ass the next day.

[jdpete]

manu,

At 15% efficiency increase is that with direct fire or internal elements, or does that not matter. Also, at what preheat feed temperature into the column is that figured at?

Jeff

[manu de hanoi]

manu,

At 15% efficiency increase is that with direct fire or internal elements, or does that not matter. Also, at what preheat feed temperature into the column is that figured at?

Jeff

Either heating, it doesnt matter. I don't remember the exact temperature of preheating but it should be around 60 C for direct heating and 65 C for steam injection. You'll need a better heat exhanger than the one in my video.
I just made some updates of my calculations for pre heating parameters, you should re download the excel file here
http://homedistiller.org/forum/viewtopi ... 1#p6848456

[jdpete]

Finally got my continuous stripping still operating without leaks. Here are the specs on the still and the feed rate per minute:

- pump is a 2 roller peristaltic with a homemade bypass using a needle valve.
- 5625 watts effectively using 4700 watts based on boil up time.(51 min. with 11.5 gal. startup water charge in keg)
- 4" bok still with 20" of copper mesh for stripping section. Also used vapor distributor and liquid distributor.
- 11" liebig (3/4"x1/2") for preheating using spent wash. raised feed wash temp from 62F to 100F.
- feed rate was 530ml of wash per minute. wash is 10.4% alcohol.
- feed rate adjusted to 201F at head and 211.5F at boiler.
- output was 100ml per minute at 50% abv.

The stripping section of the column was not insulated and and there was no insulation around the boiler.
Tommorrow I plan on insulating the stripping section and the boiler and seeing if I can increase the feed rate a little more.
next goal after that is to add another 11" of liebig to see if I can increase the feed rate to about 140F.
My goal is to get to 700ml per minute feed but I am not sure if the suggested changes will allow that.
I'll report back after runs.

Jeff

[manu de hanoi]

did you check my calculator ? I think that you are already close to the theoretical max you can get out of your power

[jdpete]

I looked at it once but was not sure as to what all the variables were that needed to be entered. I'm not much of a math person.
What do you see as the maximum being?

Jeff

[manu de hanoi]

for the 530ml/min feed I get 4953 Watts required on direct heating and 5712s Watt required on steam heating
for 700ml/min 6541 Watts required on direct heating and 7544 Watts required on steam heating

These are theoretical numbers, in real life some power is wasted on areas of the still that are poorly insulated

[jdpete]

Thanks!

Do you think insulating the boiler would help much?

Jeff

[manu de hanoi]

it would help a lot

[jdpete]

I must be getting some reflux going on because the abv goes up higher the more feed I push, up until the boiler temp starts to drop. I am running it right now and at 196F I am getting 58% abv. coming out. output does not change but the abv does.

Jeff

[jdpete]

Hi Manu,

Thanks for your help with the calculations. After insulating the stripping column and the boiler I got a wash feed rate of 640ml per minute. I was thinking of adding a little more liebig to the preheat but am not sure if it's worth the effort. I am feeding at 100F right now and was thinking of raising it to 135F.

Jeff

[The Baker]

Theoretically, I suppose, and oversimplifying the whole thing, and ignoring the 'continuous running' possibilities and the problems of matching the heat and the water flow and so on;

(and I'm thinking as I write this...) and ignoring heating-up time.

You could have, in effect, a pot still without a condenser;

feeding the vapour into (about) the middle of the column of a reflux still

(which for the purpose of illustration could be running a medium quantity of feints; and which COULD be steam operated).

Savings in time and cost would result from not having to expend energy in condensing the vapour from the pot still part of the operation, and then having to again expend energy (time and money) in turning it back into vapour in the reflux still.

[jdpete]

Manu,

Have you ever had any problems with co2 in the feed wash causing problems? I recently ran a continuous run and had to fuss with the feed alot. Never had to do that before.

Jeff

[manu de hanoi]

if you have preheating and a lot of Co2, that could cause issues. But you don't get too much co2 if you distill dry and rack twice.
Racking is especially important if you dont want your column full of goo

[jdpete]

What kind of issues are most prominent with to much co2 present?

Jeff

[manu de hanoi]

What kind of issues are most prominent with to much co2 present?

Jeff

the feed spurts after the preheater, can even splash around