First run on new bokakob inline - added pics

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erbachem
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Posts: 75
Joined: Tue Oct 03, 2006 7:01 pm
Location: New Zealand

First run on new bokakob inline - added pics

Post by erbachem »

Hi All,

Well, after months of threatening to get a bokakob inline still up and running I have finally done it. I'll post pictures shortly but thought I'd do a once over of the first run to see what people think. Here goes.

The still.
bokakob inline
Column = 75mm diameter, 1m length. Currently only 85cm of copper mesh installed until I can order more.
Boiler. Converted keg with 1x 1kw and 1x 2kw elements installed.

Charged with ~45 litres of tomato paste wash pre-stripped and measuring 50% abv.

The first pleasant surprise was when I found that the condenser was good enough to keep up with both elements going at the same time. These forums have suggested that 3kw should be okay for a 3 inch column so I just let both go right through to the end. I initially ran the still at 40ml/min achieving 88% abv. Later on I upped the rate to 50ml/min with a resulting abv of 87.5%.

First on the priority list is to get some more copper mesh to fill the entire column. I am also thinking about fitting a 50cm extension.

So first question, are there any other quick wins I can do? My next goal is to get 90-92% without having to stay up all night. Any recommendations from the old hands out there?

New Boka setup. The blue bit is a piece of silicon sleeve from Repco (car parts shop). Seals extremely well.I still need to make room for the thermometer

Image

Close up of the condenser.

Image

Here is my pot still. Used for stripping and the odd rum / bourbon run.

Image
Last edited by erbachem on Mon Jun 02, 2008 10:27 am, edited 1 time in total.
ME
erbachem
Novice
Posts: 75
Joined: Tue Oct 03, 2006 7:01 pm
Location: New Zealand

Re: First run on new bokakob inline

Post by erbachem »

So I just did a quick calculation using the reflux still calculations page and it tells me that I should be getting 94.4% out at 4.6 litres per hour.

The 4.6 litres per hour I think is pretty easy to explain. I knocked 1kw off for heat loss and it came down to ~3 litres per hour. Insulation is now high on my priorities.

So is 94.4% the theoretical maximum or does this indicate problems with my existing design? I was only able to get 88% out.
ME
Hawke
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Posts: 2471
Joined: Tue Mar 25, 2008 1:39 am

Re: First run on new bokakob inline

Post by Hawke »

Once you have the column fully packed your ABV will jump up there. That is a pretty fast take-off rate. If you got 88% with limited packing, you are in good shape.
It is the very things that we think we know, that keep us from learning what we should know.
Valved Reflux, 3"x54" Bok 'mini', 2 liebig based pots and the 'Blockhead' 60K btu propane heat
tracker0945
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Joined: Thu Aug 09, 2007 8:28 pm
Location: Oztraylia

Re: First run on new bokakob inline

Post by tracker0945 »

Your takeoff rate will improve with more packing for sure but what you may find is that along with that fast rate, you may drag some of the tails through into your hearts.
I found with my still that to get the quality and clean cuts along with the high abv%, I had to reduce the speed of the take-off.
Cheers.
2"x38" Bok mini and
Pot still with Leibig on 45 litre boiler
Hawke
retired
Posts: 2471
Joined: Tue Mar 25, 2008 1:39 am

Re: First run on new bokakob inline

Post by Hawke »

Unless I'm stripping, I like to stay under a litre an hour. (3" Bokakob 'mini')
The tails cut comes like flipping a switch. It does take a while though.
It is the very things that we think we know, that keep us from learning what we should know.
Valved Reflux, 3"x54" Bok 'mini', 2 liebig based pots and the 'Blockhead' 60K btu propane heat
glassman
Swill Maker
Posts: 231
Joined: Thu Jan 03, 2008 4:14 am

Re: First run on new bokakob inline

Post by glassman »

i agree with hawk. i should beable to pull 4+litres an hour but theory and reality aint allways the same. keep it slow and enjoy the ride. gman
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