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indyspirits

Carbon Filtering Redux...

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indyspirits    31

We've build a filter for our neutral spirits which we either make or buy (The Horror!!).  Previously we've run it through our column and taken a wee heads & tails cut. We simply don't have that many hours in the day. We had our local metal fab shop make a tote platform; source tote on top, destination tote beneath.  Filter setup like this:

filter.thumb.png.36d3392deae5ef36d37e2d9ed7a7921b.png

 

We have around $700 in stainless triclamp pieces and parts.  I've read, researched, and gleaned all info both factual and anecdotal.  What I can't exactly determine is:

  1. Is the filter bed of sufficient depth (it's 36")?
  2. What flow rate should we run at (?
  3. Is 12x40 coconut husk based carbon appropriate for this task?

 

TIA!

 

 

 

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Natrat    3

Not sure what you're trying to accomplish, so it's hard to comment. But my guess is a setup like this will let a lot of carbon black into your finished product. I don't see a particulate filter after the carbon bed. Will this be pumped or gravity feed?

Bed depth is a concept for gravity feed filters, as you have your constant (gravity). If you're using a pump, then overall surface area and contact time are your variables.

If you go very slowly (<1 gpm) then I think a piece of polypropylene felt filter on top of your carbon bed will help, but at higher rates, it may blind. One concern I have with using 12x40 and a pump is that there will be a great deal of trapped gas inside your filter media, and if you use a pump, you can compress all that gas, and the filter gets crazy hot...which isn't awesome for high proof product. What proof will you be filtering at? 

Personally, for a project like yours (filtering neutral) I would recommend a coarser media, and rather than filter from one vessel to another, I would set up a cyclic filter process that runs for a set time. That may also help with trapping excess black AND you can increase the speed slowly,  limiting compression heating until your carbon is fully saturated. I also like to see a particulate bed (such as washed sand, pebble, or long-strand wound poly)

If you're looking for something more aggressive, for a true neutral, then carbon block filtering may be more productive. 

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Rum    1

We use a very similar setup. In our case it is gravity fed. The source tank is elevated above the filter and collection tank. Our bed might be slightly taller, but that shouldn't be a concern. Contact time is going to determine the result with a given carbon. The volume of the bed will limit the amount of product that you can filter effectively though. 

Use a granular carbon and run it slowly. You will need to experiment to figure out how much contact time gets you the results you want. Try starting at 10 to 15 minutes and adjust from there. 

We have the housing attached to a pivot bolt so we can turn it upside down to empty it easily. 

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indyspirits    31

@Rum @Natrat

This will be gravity fed one tote positioned directly above another. I do believe I can prep the carbon bed to eliminate most air pockets.  Not sure how I'd calculate contact time with the bed. Perhaps derive from flow rate?

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Rum    1

We don't have any problems with air pockets. If it's flowing in from the bottom at a slow pace through granulated carbon that's not going to be a problem.

You can time how long it takes to get flow out the top once you open the valve on the bottom. 

The flow rate may change over the run as the upper tank empties. We have learned to look at the flow coming into the bottom tank and can adjust accurately enough just by looking at it. You can catch outflow in a container if you want to be more accurate. See how long it takes to catch a liter and adjust accordingly. 

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indyspirits    31

Thanks @Rum!  I've stopped worrying about making it perfect the first go around. We'll collect flow-rate info and our organoleptic evaluation and if it needs more filtering we'll swap tote positions and run it again. Thanks for your thoughts.

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I think this was already implied by the other comments, but, you shouldn't need 2" piping on the feed or output.  I would imagine 3/8 to 1/2 ID tubing would be more than sufficient.  It's the difference between what looks like $200-300 in triclamp spool and fittings and $20 in tubing.

Oh, and you need submicron filtration after the carbon.  

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kelbor    0

We use a very similar system with good results - but at a very limited capacity. We use  .5" tubing for neutral to flow from tank to tank. I let it flow through the carbon at about a rate of 25 gallons in 12 hours. I do this as many times as needed until I feel it taste clean enough. (usually around 4-5 passes through the filter bed). Our filter bed is 36" tall and 4" in diameter and we use coco carbon with a few stainless filters at the top of the column. Carbon dust is rinsed out before using the filter for the first time and seems to be removed fairly completely by passing the neutral through the filter several times. Don't forget to place a few ball valves - one at the top and one at the bottom of your filter canister so you can isolate and/or remove for filling or whatever. I also use these valves to adjust flow rates and to close off the filter between batches. We store our filter full of vodka - not sure if that matters though.

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kelbor    0

Also, you will want to have your "Neutral In" pipe higher then the "Neutral Out" pipe to the whole holding tank will drain....maybe its just looks wrong on your napkin drawing.

 

Note: I see the valves now. Looks Great!

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