Height to introduce wash in continuous still?

[Faben]

He all, greetings from South Africa. first post here, been following this wonderful site for about a year now.
I have built a standard stainless boka. I have a potential 120L 10% wash bubbling away thanks to birdwatcher,, Wondering about your guys opinions on continuous distillation...

My boka reflux column is 63cm (~25in) and diameter 5cm (~2in) stuffed with copper scrubbers. It has a 3000W element, fully controllable. The cooling coil can easily handle anything 3000W can throw at it.

1) For continuous stripping runs only: Should I just put a wash 'introductory hole' right below takeoff point to get a speedy stripping run or will it vastly improve final product if I make it lower down and allow a rectifying section to strip tails?
I hear you should dilute the product to 40% anyhow when doing a proper secondary reflux.

2) I do not have a digital thermometer to measure the temp of the boiler. I have been relying on low-end 'analog?' cooking thermometers to measure the 78 at takeoff point. Is it possible to efficiently run in continuous mode without an accurate reading off the boiler?
(I get maybe two, max three degrees off which is obviously bad for detecting precise drops below 100).. I suppose I could admit defeat and buy an accurate digital one but for short term, I really want to get that 120L out of those drums (heheheh) so any advice on that?

Thanks in advance guys.
Oh and feel free to ask add info, pics (not the prettiest lady) and anything else.

[Wim]

He all, greetings from South Africa. first post here, been following this wonderful site for about a year now.
I have built a standard stainless boka. I have a potential 120L 10% wash bubbling away thanks to birdwatcher,, Wondering about your guys opinions on continuous distillation...

My boka reflux column is 63cm (~25in) and diameter 5cm (~2in) stuffed with copper scrubbers. It has a 3000W element, fully controllable. The cooling coil can easily handle anything 3000W can throw at it.

1) For continuous stripping runs only: Should I just put a wash 'introductory hole' right below takeoff point to get a speedy stripping run or will it vastly improve final product if I make it lower down and allow a rectifying section to strip tails?
I hear you should dilute the product to 40% anyhow when doing a proper secondary reflux.

2) I do not have a digital thermometer to measure the temp of the boiler. I have been relying on low-end 'analog?' cooking thermometers to measure the 78 at takeoff point. Is it possible to efficiently run in continuous mode without an accurate reading off the boiler?
(I get maybe two, max three degrees off which is obviously bad for detecting precise drops below 100).. I suppose I could admit defeat and buy an accurate digital one but for short term, I really want to get that 120L out of those drums (heheheh) so any advice on that?

Thanks in advance guys.
Oh and feel free to ask add info, pics (not the prettiest lady) and anything else.

Kan `n mens in die RSA nie beter mampoer stook nie?

On a different note, you always should dilute your product below 40% before distilling again. Higher ABV's can cause explosions.

A good thermometer is always better, but once you have your column running well and you reflux properly, your temperature at the TOP of your column will remain stable untill all the alcohol is consumed. You will notice a sharp increase in your temperature as soon as the alcohol is depleted, you will notice this with the cheapest thermometer you can find as well as the most expensive. For a good reflux column you will need some more height but I guess you allready read that in the forum.

On another different note, are you sure ESKOM will be able to handle your fully controlable element? Or are conditions improved over there?

[Faben]

Kan `n mens in die RSA nie beter mampoer stook nie?

Ek woon in kaapstad, ek het net Fruit & Veg City om my Naartjies te kry.. Te duur en ek is nie lus vir drie uur om die pad om n lekker plaas te vind nie.. Ek het 50kg suiker vir R240 laaste week verkoop!!
Enige tips om lekker vrugte in die Kaap te kry?
Eskom is a little better, only an unscheduled power cut about once a week now

Hmmm I do realise the column is a little short, I just don't have the energy to extend it.
Are you talking about a reflux still or a continuous reflux still where wash is introduced somewhere along the column?

[Wim]

Kan `n mens in die RSA nie beter mampoer stook nie?

Ek woon in kaapstad, ek het net Fruit & Veg City om my Naartjies te kry.. Te duur en ek is nie lus vir drie uur om die pad om n lekker plaas te vind nie.. Ek het 50kg suiker vir R240 laaste week verkoop!!
Enige tips om lekker vrugte in die Kaap te kry?
Eskom is a little better, only an unscheduled power cut about once a week now

Hmmm I do realise the column is a little short, I just don't have the energy to extend it.
Are you talking about a reflux still or a continuous reflux still where wash is introduced somewhere along the column?

I lived pretty far from Cape Town, I lived near Lydenburg close to Nelspruit. Lots of fruits there.

If we talk about hobby stills we usually speak about a kettle that is filled prior to distillation (batch operation). If you want a continues still you will need to expand your hobby. I don't know your plans further, but I would say a reflux still like most of us use is the way to go.

If you don't have the time or energy to extend the column you can just wait and see what product comes out and redistill it to get to get a purer product. Be warned though if you want a pure product, you will propably take longer to obtain it with your current setup, than modifying it to a higher column and then make the run.

[rad14701]

Greetings, Faben...

How much "packed column" does your short column have...??? For a 2" column you should have a minimum of 24" of structured packing and 36" to 48" would be better... Unless you have enough packed column you won't be able to attain and maintain the levels of purity that I am assuming you are striving for...

Also, I really don't see the Bokakob as being used for continuous distillation... Do you have a drawing of what you are contemplating...???

[Faben]

I have 25" packed column, 35" total. Sorry for not being clear.

Here is a 5min paint diagram, I know, I am in a hurry but I think it conveys the idea.

As I slowly feed wash into the middle of the top of the column drip by drip, it is held by the scrubbers and rising vapors heat it up and the alc rises to takeoff point and the water falls back down. Am I missing something here?

[Wim]

I have 25" packed column, 35" total. Sorry for not being clear.

Here is a 5min paint diagram, I know, I am in a hurry but I think it conveys the idea.

As I slowly feed wash into the middle of the top of the column drip by drip, it is held by the scrubbers and rising vapors heat it up and the alc rises to takeoff point and the water falls back down. Am I missing something here?

Ah thats sounds a lot better.

If you do want to try this, you should introduce the wash lower. My gut feeling says you will need a higher column if you want to introduce it this way.

If I was to try something like this I would make a column so that you have a minimum of 24" packed column above your introduction point, and enough packing below the introduction point to allow the introduced wash to be completely distilled before it drops to the kettle below. In essence you don't want your introduced wash to fall through the packing without seperating the alcohol contents first.

Don't forget that the mash should be introduced in the middle of the column!

[Faben]

Yea thanks.. So I suppose 25" is the minimum packed length below introduction point for an efficient strip.

So I gather my options are:
1) Extend column
2) Try introduce just below takeoff point and see how it goes. Low alc %, lots of flavours but this is just a stripping run so maybe it will be fine..

@Rad I am indeed striving for a 90+ neutral for schnapps.

Any opinions about second option? Anyone?

[Dnderhead]

""Low alc %, lots of flavours but this is just a stripping run "
not with a packed column..

[Faben]

""Low alc %, lots of flavours but this is just a stripping run "
not with a packed column..

Thanks dnd, so seems I wrongly assumed without rectifying section above inlet, column would act more as a continuous pot still.
I am completely new to this, still a student and have much to learn so excuse my ignorance..

So around what purity can I expect if I introduce wash at top of 25" column and would production speed be worth it?

thanks guys

[rad14701]

You definitely wouldn't want the raw wash entering above the structured packing... You would want it to enter either into the top of the boiler or about 1/3 up, into a coarser structured packing than scrubbers... I can envision finer packing quickly becoming encrusted with gooey sediment if the ash wasn't perfectly cleared...

The whole concept of continuous stills arises every couple of months but nobody has come up with an efficient small scale version that has caught on... On such a small scale you could easily lose a higher percentage of alcohol out the waste pipe than would be left behind in the boiler with batch distillation...

[Faben]

Well it seems it is not worth the losses, babysitting etc to attempt this, rather just replace wash in boiler with a nice valve.
Lucky I got your guys advice first.

Thanks all for helping me out

[jorel]

The whole concept of continuous stills arises every couple of months but nobody has come up with an efficient small scale version that has caught on... On such a small scale you could easily lose a higher percentage of alcohol out the waste pipe than would be left behind in the boiler with batch distillation...

What about this: http://homedistiller.org/equip/cont" onclick="window.open(this.href);return false;" rel="nofollow ?

Is this not a viable design/implementation?

I'm a newbie, so maybe I'm missing something, but it seems like, for producing fuel alcohol, a continuous still would be pretty nice.

[Prairiepiss]

Making alcohol fuel at home isn't all that viable.