TPW Boka Problems too much tails and too early

Reflux still design and discussion

TPW Boka Problems too much tails and too early

Postby egg85 » Fri May 12, 2017 12:27 pm

Hi,

I have a 3" slant plate boka with liebig controlled by voltage and output only.
I have done about 20 or so spirit runs and never had a problem except when experimenting/learning on the first few.
Running TPW. About 50/50 copper/stainless packing.
Water flow has not changed, I am not controlling thou.

I started having a problem with the tails coming in too early and too much of it.
The last 2 fresh runs I'm getting tails where there should be only heads.
So I started looking for problems.
I cleaned the copper mesh, no change
Run a citric cleaning run, no change
Replaced some of the copper mesh with new stuff (soaked in heads and then in citric), no change
Replaced all the stainless and old copper mesh for new copper, no change
Soaked the water side of the condensor in vinegar/water in case it had corrosion and was stopping heat transfer, no change
I have tried 3 different stripped runs, no change
I have tried running the power so low I was only just getting output (not good for reflux, but should separate everything), no change

I don't know what else to try. The only weird thing I have noticed is that on the stripping runs the output is slowing before the temp gets as high (95 degrees it never used to slow at all until I shut down at 97 or higher). I'm not controlling by temp but it has always been consistent.

Can anyone help
Thanks
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Re: TPW Boka Problems too much tails and too early

Postby Minpac » Fri May 12, 2017 12:29 pm

SG readings on the wash? Maybe you're getting stuck ferments in the cooler weather, so there's less product? This might explain the high temps once and slowed product - you're out of ethanol to distill?

Just my guess...not much refluxing experience yet.
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Re: TPW Boka Problems too much tails and too early

Postby Dogfish » Fri May 12, 2017 1:16 pm

Maybe a leak somewhere.
My last run was like that, and I'm thinking I have a leak.
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Re: TPW Boka Problems too much tails and too early

Postby hillzabilly » Fri May 12, 2017 1:21 pm

Are ya getting the same volume as usual from a run or not.cheers hillzabilly :handgestures-thumbupleft:
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Re: TPW Boka Problems too much tails and too early

Postby egg85 » Fri May 12, 2017 1:50 pm

Thanks for the replies guys

Wash ferments are fine. I did have some that did finish early maybe in the first failed run.
The last fresh batch was all good, I had one drum still bubbling like crazy at 0.990 using bakers yeast. I have heaters in some of my drums, but sometimes the unheated ones ferment better

Striping run volumes are fine. Spirit runs I haven't bothered to finish them properly cause they are shit early.
I haven't noticed any leaks, I'll have a look more closely next time. But the amount it is happening its like I'm letting the vapour pour out the top for an hour.
:angry-banghead:
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Re: TPW Boka Problems too much tails and too early

Postby egg85 » Fri May 12, 2017 1:56 pm

Forgot to add. The last stripping run I ran pretty slow to try and make sure it was good.
It came out at 60% which would suggest it should have not much tails in it. I watered it down of course.
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Re: TPW Boka Problems too much tails and too early

Postby coffe addict » Fri May 12, 2017 2:55 pm

60% is quite low for a boka. I'd be leaning towards not a high enough reflux ratio.
What power in put and what take off rate?
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Re: TPW Boka Problems too much tails and too early

Postby egg85 » Fri May 12, 2017 3:17 pm

60% stripping run is high, normally collect until temp 97 and it it at 40%. Stripping run is without packing.
The spirit run always comes out over 95%
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Re: TPW Boka Problems too much tails and too early

Postby Zak Griffin » Fri May 12, 2017 3:23 pm

If you're stopping your strip run at 40% you're leaving a lot of good alcohol in the boiler.
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Re: TPW Boka Problems too much tails and too early

Postby ed9362 » Fri May 12, 2017 4:04 pm

My simple 2 inch boka can run 93 from the wash all day.

Are you sure your cooling is sufficient
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Re: TPW Boka Problems too much tails and too early

Postby coffe addict » Fri May 12, 2017 6:12 pm

Sorry bud I got confused as the topic was about your boka getting too much tails and I saw 60%.
I'd still lean towards there not being enough reflux. What power are you running at and what is your take off on spirit run?
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Re: TPW Boka Problems too much tails and too early

Postby warramungas » Fri May 12, 2017 6:47 pm

Using a boka you should be able to strip fast at a fairly high abv. 80% was not an unheard of number for me and then the abv would drop real fast at the end. This was at full noise and only a very small reflux ratio just to bump the strength a little bit. My pot will do 60% on a 10% wash at least initially.
Try refluxing for a while when you think your tails are starting to appear. A 3" boka should be ok to run 2400 watts or less if its insulated. I've heard of people here running higher power but you need the reflux ratio to keep the strength up. Less power is not always better with a boka. You need to find the sweet spot.
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Re: TPW Boka Problems too much tails and too early

Postby egg85 » Sat May 13, 2017 8:21 am

Zak - Sorry not stopping at 40% when I stop the whole run is at 40% mixed. I don't have a parrot.
ed - I could get 93% direct from the wash with the packing but that would be really slow. Easier to run a few fast strips with no packing then a slow and larger spirit run.
coffe - I have 2 2200w elements, after boiling I normally have them at 130volts when I start my collection and at the end about 150volts. Takeoff about 250mls every 4 mins. The point is I was running like this for 20 or so runs everything was fine, something has changed but all the inputs and outputs are the same.
warra - I do run a little reflux during the stripping run. I don't know the percentages during the run but I get about 8-9 litres at 40% from 45 litres of wash. I don't measure starting sg anymore but most finish in the 0.99 range. I have had some problems with pH or not enough TP but this was happening when I was getting good runs as well.
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Re: TPW Boka Problems too much tails and too early

Postby coffe addict » Sat May 13, 2017 9:11 am

So that puts your take off at 3.75L an hr. With about 2.4Kw.

I'm not familiar with 3in take off speed but that is the power I used to put into a 2in I'd be bumping to 3 or 3.6kw and slowing down to 3L an hr that is going to hold tails down in the column and stop them getting dragged through.
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Re: TPW Boka Problems too much tails and too early

Postby egg85 » Sat May 13, 2017 11:07 am

Thanks coffe, I can try that and I have run slower before with only marginal quality increase. I found that speed to be my happy medium.
I don't think that is my main problem though. I am getting tails within the first litre
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Re: TPW Boka Problems too much tails and too early

Postby Kenster » Sat May 13, 2017 8:42 pm

egg, i run a 3'' bok, tails in the first lit... crazy...should not happen. I always let the col stack/reflux, probably too long and i take off too slowly, compared to figures bandied around. I would suggest to run it much slower as a separation test, where the fractions should do what they are meant to.
I too built a 3'' assuming i could fly thru the whole exercise with ease yet found that slower is better.No point getting 3 lit per hr of shit.
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Re: TPW Boka Problems too much tails and too early

Postby egg85 » Thu May 18, 2017 8:44 am

The problem is mostly fixed. I believe it was caused by 1 roll of mesh being too tightly wound and also pushed up the column too far possibly causing flooding around the slant plates.
I have dropped some quality down to 93 percent no matter how slow I run (I always got at least 95 before) because some of the other packing is not as tight

I did some testing while holding the temp and refluxing which I always do for 30mins to an hour.
Didn't find any leaks. Did consider the possibility of a leak into the water side, but that would have caused an airlock in the water. The same airlock I clear at the start of every run.
I can turn the power up to 170 volts with both elements before I get any vapour getting through the condensor.
At 160 volts and holding the water temp input was 15 deg output 30 deg and flow 2.5 L/min. Product output 22 deg
And my takeoff speed estimate must have been way off, cause I definately wasn't getting 3.75 L/hour on previous runs.
These numbers probably don't mean much in something custom built, but might be handy if I have more problems in the future.

Thanks for the brainstorming everyone :clap:
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Re: TPW Boka Problems too much tails and too early

Postby Dogfish » Thu May 18, 2017 2:25 pm

I'm glad you got it sorted out.
How do you measure your water input and output temp and flow rate? Something I need to start doing.
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Re: TPW Boka Problems too much tails and too early

Postby egg85 » Thu May 18, 2017 7:22 pm

Dogfish, I put either my temp probe or temp gauge in the 1000L fish pond where my water gets pumped from to get input.
And in the return to the fish pond to get outlet temp.
For flow, I put the return hose in a 20L bucket and timed it
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