Question about mixing column packing

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4runner
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Question about mixing column packing

Post by 4runner »

Hello,

I had a question regarding column packing that I either havent been able to find using the search function (likely), or perhaps it hasnt been asked yet.

Simply put: How best would you order the layers in a column that has 2 different types of packing? Specifically, in a 6ft 3" LM modular column that utilizes 36" worth of rolled copper mesh and 22" SS SPP, would you place the SPP on the top half or the bottom? I would guess that SPP on the top half with mesh on the bottom is superior, as my gut would lead me to think that the partially flooded state of the SPP will cause issues with the mesh on top. On the other hand, SPP being more efficient might be best served under the mesh? I dont know, and so I bring my quandary before you all.

Although I have what I am looking for (close to azeo neutral), I am looking for more stability in the column and faster production through adding more heat, which has led me to believe that more HETP will help (as will more experience in general), thus the addition of SPP to replace the plates.

For context, I currently run a 16g boiler with copper mesh in the bottom half of the column and have a glass section with 4 plates on top before the takeoff. This setup may sound weird, and I probably agree, but its just what I have so I use it. My guess is that Im currently getting around 20 HETP or so, but I struggle with the math of it all. It currently produces about 2l/hr of 95% using 4kw to heat up and 2kw to run with a charge of 40% low wines. I can recover 95% with a sugar wash at 10%, but its slower, more finicky, and I just prefer to strip first and store for a rainy day to do the spirit run. My plan is to simply replace the plate section with SPP.

I will ultimately convert the column to straight SPP, but it aint cheap and I want to make do with what I have for now. So what say you: mesh on bottom and SPP on top, or SPP on bottom and mesh on top?

If you need more info for context feel free to ask! Thanks all!
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bunny
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Re: Question about mixing column packing

Post by bunny »

Hi!

I'm an "old" novice not set in any particular way of doing things.

If those are your only two choices (top or bottom) you're better off just trying both and decide for yourself.

If you desire (as I do) tasteless, insipid, boring neutral consider stepping back and re-evaluating your situation.

You apparently have an empty 6ft x 3" LM column.

What can you put in it to get you what you want?

There are quite a few different packing materials to read about here.

For me, the key has been to be able to sift through the praises of the majority who desire at least some flavor in their end product and those (like me) who do not.

Might I suggest properly sized lava as an inexpensive yet wildly efficient packing?
richard1
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Re: Question about mixing column packing

Post by richard1 »

Always try keep copper to the base of the column and better still if it is easily removable. This will aid in cleaning. I designed a column where I can at will insert and remove the copper. Yes have the copper for stripping.

I am of the opinion the SPP is too small for your column, the SPP at approx. max 5.5mm diameter and 4.5mm length.

Having both plates and packing to me is non sensical. With the plates you change the column dynamics where tails is held back
richard1
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Re: Question about mixing column packing

Post by richard1 »

Regarding your column, you indicated 3", SPP, 2KW @ 2lph, this rate for when you are running with high reflux for high %ABV take off.

What rate do you achieve when stripping.
4runner
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Re: Question about mixing column packing

Post by 4runner »

Thanks Bunny! I figure Ill work with what I have but I wouldnt mind trying lava rock in the future. It certainly seems attractive, if only for the price alone! Ive been considering building an economical backup column and might end up getting some for that.

Richard1,

I can strip 14g in my potstill setup at 4kw (all I got) in about 4 hours or so including heat up. Ends up at around 40% so about 3.5-4gallons. I take everything from start to finish when stripping, save for the first couple hundred ml's just to remove some nasties to save time during the spirit run. Ive never put copper in my strips, but Im not opposed to the extra step and will give that a try.

Yes 2l/hr is the average after heads are removed for spirit runs. You might be right on the entrainment of tails in the plates. I find that although the run does have a noticeably hard cut into the super nasty tails with lets say 5% left, I typically slow it down a touch or close the valve for the last quarter and let it equilibriate (sp?) for about 5 mins a couple times to at least slow smearing (temp will pick up .1 degrees or so). I am hoping that simply having more HETP will stabilize it better, but not sure how much to be honest. Overall Im just trying to automate the process more and speed it up given my limited knowledge and any little bit helps!

Hoping the spp is not too small :/. Mine is 4mmx4mm. I found a data chart somewhere in a thread here that gave estimates for what different sized SPP can handle for 3", heatwise, and expected performance. Not sure how accurate it is, but I figure if I can get more stability, an extra 500w, and greater purity or so Id be pleased with that.

I think I will go with Mesh on bottom and see how it goes. Ill report back after I run. Thanks for the feedback and keep it coming if you have the time or see any red flags.
4runner
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Re: Question about mixing column packing

Post by 4runner »

Also: 2l/hr is using my current mesh/plate setup. Havent used the spp yet.
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