low abv in reflux glass bubbler colum packing maybe?

Perforated & bubble cap plated columns

low abv in reflux glass bubbler colum packing maybe?

Postby austenpowers » Sat Feb 16, 2019 4:11 pm

Ok guys here is another one for ya ~x(

i ran my newly built and assembled 4" stainless steel still, it has 4 bubble plates with 5 bubble caps configured with a 650mm long packed section above the plates.

the abv never went above 90% and the top bubble plate filled right up in full reflux mode

i remember having this problem (low abv) with my 3" still (packed column non bubbler) and i added more scrubbers, i think till i got to 94-95%

is there a method or rule of thumb for packing vs abv ? or how much is to much or the effects of to much vs not enough??
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Re: low abv in reflux glass bubbler colum packing maybe?

Postby db1979 » Sat Feb 16, 2019 8:24 pm

Sounds like your top downcomer isn't coping. What were the other plates doing?
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Re: low abv in reflux glass bubbler colum packing maybe?

Postby bluc » Sat Feb 16, 2019 8:27 pm

Running to hard? How much power you throwing at it?
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Re: low abv in reflux glass bubbler colum packing maybe?

Postby austenpowers » Sat Feb 16, 2019 11:02 pm

i had the 2400w stick running hard and the small ring gass burner going out of a double ring burner
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Re: low abv in reflux glass bubbler colum packing maybe?

Postby austenpowers » Sat Feb 16, 2019 11:34 pm

i turned off the gas and the element and one by one the plates collapsed the top first and the next and so on.

i waited till the plates were even and the bubble caps were all covered the same and turned the element back on, 10 minutes later i adjusted the r/c till i had 78 going to the p/c
the rest of the run was topping out at 90% and below, abv

the bubble caps remained covered plus 10mm for the run on all plates , which is why i drew my assumption to the packing in the column above??
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Posts: 38
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Location: Tasmania
equipment: 2" reflux ss column 25 L boiler 2400w ring
3" pm & vm reflux ss 50 L boiler 2400w stick

Re: low abv in reflux glass bubbler colum packing maybe?

Postby db1979 » Sat Feb 16, 2019 11:51 pm

Too much heat. My 4" bubbler can bubble away on as little as 1200 to 1400 W. If I run it on 2 x 2000 W elements the second one needs to be dialled right down with my voltage controller before the plates behave properly. The flooding you saw was your downcomer not coping. I'm surprised you didn't see blow-through of your downcomers.

Have you checked the calibration of your alcometer? Put it in tap water, it should read zero.

Is your alcometer oversized for your parrot? You may be getting a lifting effect on your alcometer if it is too close a fit to the walls of your parrot, causing a lower abv reading than what it really should be. Test the cuts you've made in a jar and compare to the parrot reading for the same cut, if it's different then your parrot is too narrow.

Alternatively, you're just running it too fast. What collection rate are you getting? If you are collecting too fast, you are using too little cooling which equates to too little reflux and then abv drops. I doubt this is the case though cause you had flooding issues.

Perhaps you could try running with less than 2400 W but I thought bubblers with packed sections needed more heat. But I have no experience with packed sections. :think:
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Posts: 1760
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Location: South of the big smoke in banana bender land.
equipment: Eve - 4" x 4 plate solid state bubbler (sieve plates), 330 mm packed section on a keg boiler with 2 x 2000 W elements.
Currently having a makeover: 2" x 4 plate solid state bubbler (1" bubble caps, no sight glasses...maybe not for much longer!) on a bain-marie boiler.

Re: low abv in reflux glass bubbler colum packing maybe?

Postby scythe » Sun Feb 17, 2019 6:58 am

Why do you have 78 going to the PC?

It does soud like flooding of the top plate.

But if %ABV tops out and your starting with a wash in the boiler then you have either found the max your still is capable of (unlikely) or you are not running it with enough reflux and at the correct take off rate.
:think:
You don't mention the output rate.

Bubblers need reflux and they need to get to an equilibrium before you start getting output.
How fast you let product come out governs the %ABV.
If you are not getting the %ABV you want at the output you want then you need to add more plates.

What size are your downcomers?
1/2" or 3/4"?

General consensus for bubblers starting with a wash is 2L/Hr, low wines you can acheive higher rates as you have more ethanol to start with in the boiler and it needs less separating from water.
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Re: low abv in reflux glass bubbler colum packing maybe?

Postby db1979 » Sun Feb 17, 2019 7:58 am

Another issue, since your location says Tasmania, I'm wondering if it's possible your cooling water is cold enough so the output of your PC is less than 20 degrees C and this will result in a lower abv reading, as alcometer are calibrated for 20 degrees C. I checked the weather in Launceston and today it's supposed to Max at 21, with a minimum of 9. You could be somewhere that's cooler or warmer than Launceston, but it's still worth while considering. I'm guessing that it's possible your cooling water may be too cold for an accurate parrot reading. :think: :think: :think:
Forgive me in my sub-tropical naivety if I'm way off the mark.
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Posts: 1760
Joined: Sat Dec 29, 2012 3:47 pm
Location: South of the big smoke in banana bender land.
equipment: Eve - 4" x 4 plate solid state bubbler (sieve plates), 330 mm packed section on a keg boiler with 2 x 2000 W elements.
Currently having a makeover: 2" x 4 plate solid state bubbler (1" bubble caps, no sight glasses...maybe not for much longer!) on a bain-marie boiler.

Re: low abv in reflux glass bubbler colum packing maybe?

Postby hillzabilly » Sun Feb 17, 2019 12:02 pm

scythe wrote:Why do you have 78 going to the PC?

It does soud like flooding of the top plate.

But if %ABV tops out and your starting with a wash in the boiler then you have either found the max your still is capable of (unlikely) or you are not running it with enough reflux and at the correct take off rate.
:think:
You don't mention the output rate.

Bubblers need reflux and they need to get to an equilibrium before you start getting output.
How fast you let product come out governs the %ABV.
If you are not getting the %ABV you want at the output you want then you need to add more plates.

What size are your downcomers?
1/2" or 3/4"?

General consensus for bubblers starting with a wash is 2L/Hr, low wines you can acheive higher rates as you have more ethanol to start with in the boiler and it needs less separating from water.

:text-+1: Setting temp at the RC of 78'c does not guarantee the correct amount of reflux,use ya sight glasses to verify the correct reflux,I remember being told to do it 15yrs ago like that ,stills and practical experience have come a long way since then,but a lot of out dated info remains on the intermaweb.Set your power and adjust output speed to between 1.5-2lt /hr,then check ABV,slow down collection to increase ABV,speed up collection to decrease ABV.A pic or two of the set up could be helpful to.The packing could be too loose or tight,I played around with my packing 3-4times befor it hit the 95% mark ,for these stills to function at their best everything needs to be working well,so do not think that its just going ta happen without you having ta fine tune a few details.cheers hillzabilly :handgestures-thumbupleft:
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