4" plates vs packed testing for neutral

[bluefish_dist]

So a while back there was a long thread on using plates vs packing for neutrals. Lots of opinions, so I thought I would put some data to it. I talked with Cranky and decided to do 5 different runs from the same wash to compare packed, plated columns, and a combination. The plan is to compare 5 plates, 5 plates with packed on top, packed of equal height and what I usually run to see how they do by the numbers. Note that all data is at ~6000 ft elevation, so my temperatures will be lower than what most people get.
Today I did the first run with 5 plates.
I started with my normal vodka base. This came in at 9.7% alcohol. I used 11.3 gallons in a keg still with 4000W of power. See photo.
Total run time was 5 hrs and I collected 10 jars (pints) while going deeper into the tails than I would usually go. Power was a full 4k watts for all except stabilization which was done at 2500 watts for 30 min.
The head temp during stabilization was 165.3 which suggested that I would not hit azeo as that is usually 164 +/-.5 deg depending on the day. Once I got it running I was able to hold 165.5 F at 3 turns out on the valve. Valve is a 1" on a 2" path. This is pretty much the minimum opening and max reflux while still allowing takeoff. So not looking good for doing a neutral with only 5 plates. I checked the ABV on jar #3, still 165.5 F and it was 188.3 proof at 72.4 F, which converts to 185.1 proof. I also did a time to collect 300ml, which was 15 min 10 seconds. So my take away is 5 plates wont come close to making azeo from a 10% wash/wort.
By the end of the run the bottom 3 plates were fogged and head temp had increased to 180F, which I know is ~150 proof.

I tried to increase takeoff, but if I did the head temperature increased. Once the takeoff was reduced the temperature came back down.

Tomorrow is packed over the 5 plates.

[cranky]

Cool deal. I'm very interested to see how this turns out.

[MichiganCornhusker]

I like to watch!

[ShineonCrazyDiamond]

Fun! Thanks blue!

Although subjective, will there be a taste comparison? Not all azeo is created equal, after all

[HDNB]

Bluefish can you explain that still a bit? it lloks like a VM on the left, LM on the right and a CM down the middle.

[bluefish_dist]

It is a lm/vm combo. No cm as I run recirculated water. The right side is pretty much a Nixon/stone offset. All tri clamped, only had to weld a pipe into the reducer. The left side is a vm with a gate valve. For neutrals I run a 1" valve since I don't go anywhere close to 4:1 reflux. When running it on plates alone for flavors, I run a 2" valve to allow for a lower reflux ration.
I am not a fan of the lm takeoff and use it simply for heads. It is sensitive to the valve setting and the valve I have does not have fine enough adjustment. I much prefer the vm side as it runs more stable and small adjustments like 1/4 turn will adjust head temp by .5 to 1 deg. I can run the head over 6" plates with 8000w or over a tall packed 4" pushing 4000w, works well for all of them. I am building a larger version to run on 6" plates, it has 4" T's instead of the 2".

[spiff]

I'll be watching this as well. Much appreciation for someone who can do a detail oriented test.

[bluefish_dist]

I was disappointed how the 5 plates ran, so I moved to a 35" packed section today. The 5 plates came in right at 30", so this was pretty close in height to test 1. You will notice I added a site glass under the packed, it does not have a plate in it. I added it to get the height taller so I could use the stabilizing clamp and it added the ability to see the reflux or flooding or puking (which it tried to do). Again this was at 4000w. Packing was 3m stainless steel scrubbies from walmart.

The raw data is as follows: run time 3 hours 41 min, 11.33 gallons of wash at 9.7%, head stabilized at 163.8 and settled in at 164.1 when running. We had a low pressure come through last night, so that contributed to the lower temperature. Still ran at 4.5 turns on the gate valve, jar number 3 came off at 191.8 at 74.8 or 188.2 proof. Collection was 8:16 for 300ml. Run was 10 jars, same as yesterday. You can see that the proof was higher and the take off much faster. Still not where it needs to be for me to call it vodka, but its going in the right direction.

Running the still was much easier, the column was much more stable than the 5 plate setup. Raising the takeoff rate did not immediately cause the temperature to raise. This setup would also be a lot cheaper than building a 4" plated column. A simple spool and some packing.

I also included a closer view of the still head.

[bluefish_dist]

Fun! Thanks blue!

Although subjective, will there be a taste comparison? Not all azeo is created equal, after all

Once I find a setup that can actually make azeo, yes.

[der wo]

Thank you for the experiment.
Generally for neutral I would do double runs and take off the product on the second run much slower. Or instead of slower take off probably use more wattage if possible. 4kW is something for a packed 3" column, not for a 4" column. You don't profit from the diameter with this low wattage. At least when we talk about proof and take off. Probably the same setup with a 3" column would run even a bit better.

[bluefish_dist]

My usual run is a strip run from my big still, then run low wines through the 4". I would like more power, but a 5500 w element on 208 only gives 4000w. Until I add a second element I can not add any more power. From talking with Cranky we decided to go from a wash which is worst case and it really shows the difference in how the column can separate the alcohol from the water. I would not run this way in production, but it was eye opening to see how much better the short packed column worked than the plates. I knew that already from watching the temp when running plates, but now I have hard data.

I have enough of this wash left to do 3 more runs. Next I was planning on 5 plates and 2 ft of packed. Also one plate and 6 ft of packed. Any other requests?

[ShineonCrazyDiamond]

Can you change the packing? I am a huge lava rock over scrubbies fan, and that would give a secondary packed only test. But if you don't have the packing, I don't expect you to get it just for this experiment.

[bluefish_dist]

I have a gallon of marbles I could test, but no lava rock. If someone has some to send me I will test it.

[der wo]

From talking with Cranky we decided to go from a wash which is worst case and it really shows the difference in how the column can separate the alcohol from the water. I would not run this way in production

Yes, all right. Bad for you but good for the experiment. Thanks for the effort.

[bluefish_dist]

For reference I just ran a batch of low wines with 72" of packed over one plate. Ran at 163.7 which was 191.3 proof tapering to 163.8 which was 190.3 proof doing 3 gallons in 2 hrs. This will be the next setup that I run from wash on monday or tuesday. Have to get caught up on some production first.
I expect that this setup will be able to output a azeo spirit from a wash. Output wont be as fast as from low wines, but I expect it will be reasonable fast.

[bluefish_dist]

Ran the third configuration today. Since I had been running 72" of packed over a single plate, I ran that setup. I tried to make it the same as the previous runs, 4000w, 11.3 gallons of 9.7% wash. This setup did make 190+ proof and probably could have made true azeo, but a little slower. So for the hard numbers, run time was 4hr and 5 min from start to 180 deg at still head temp at max reflux. I took off 9.5 pint jars. Time to fill 300ml on the third jar was 3 min 52 seconds or twice as fast as the 36" packed. Stabilize temperature was 164.5 and run temp was 164.6 This was a high pressure day, so those temperatures gave an output of 190.6 proof corrected from a measured 193.2 @ 71.1 deg.
I was able to run the VM section at 9 turns open for about half the run, then had to close it down to hold head temp. I probably should have run more reflux early in the run and it would have been a more even takeoff and probably taste better. The takeaway is this setup will pull 190+ and at 4-5 turns probably will do full azeo. It was also much more stable on the LM side with changes in the reflux not causing much of a change in head temp.

At the end 1/3 of the run I could not hold 190+ and it climbed to 164.7-164.8 which was 189.5 proof. To me this suggests that I need even more height to get 190+ throughout the whole run. While I have the parts to do this, I dont have the space. This setup is already touching the ceiling which is just over 12ft.
Configuration - max proof - 300ml in X min
5 plates - 185.1 - 15:10
36" packed - 188.2 - 8:18
72" packed over plate - 190.6 - 3:52

Next will be 2 ft of packed over 5 plates.

[yakattack]

Ifnya wanted to get more hight to that column, put your condensor on a 45* fitting, should get ya another foot for packing height ;p

I'm just teasing. Glad you've taken the bull by the balls with this.

You're my boy Blue.

[bluefish_dist]

I have thought about doing a hammer head condenser. That would add a little height.

[DAD300]

If you need more than 4" x 72" of packing, it is a packing problem.

If you're still using SS Scrubbies, pack them tighter.

[bluefish_dist]

Now that this test is winding down, it begs the question, what to do next. I think that a test of different packings would be useful. Now I am not up to buy all the different packings just to test, but are people willing to send me packing to test provided I send it back or just donate it to the test?

Since 3ft of packed wont hit azeo from a wash, my thought is to test each packing and then compare the ABV. Might even be able to back into HETP for each packing. If 3ft will hit azeo with that packing, then retest with 2ft to get a difference.

[ShineonCrazyDiamond]

How many liters does it take? I have a few liters I think of lava rock, and I don't think there are good research on the numbers for that type of packing. It's been estimated to perform like SPP. I don't have 2 gallons though, is what I'm estimating you might need?

[bluefish_dist]

By my calculations about 7.4 L of packing to do 36" If that is too much I could probably just do 2 ft for everything and that would only be 4.93 L We would probably not hit above 190 proof with 2 ft, but it could be used to calculate hetp.

[ShineRunner]

I have a small bag of lava rock that you could use. It's the gas grill variety.. But isn't the size of lava rock related to the column diameter? Mine is meant for a 2" column, so was going to crush to nickel size. Although I haven't busted it up yet, so that's neither here nor there. I don't think it would be near enough for a 4" column.

A size comparison (of the lava rock! ) could be useful too.

SR

[cranky]

I used the same size lava rock (scoria) in my 1.5" and 3.5" with good results. Total size was nothing bigger than a nickle. I'm wondering how much I could fit in a priority flat rate box.

[bluefish_dist]

For the 4th test, I ran 5 plates with 2 ft packed with stainless scrubbies. The short version is it ran better than 5 plates alone, but not as well as 6 ft packed. This setup did not reach azeo.

Now for the hard numbers: The still stabilized at 163.8 deg and could hold 164.1 while running. Take off rate was better 4:18 to get 300ml. The still could run a lower reflux rate with the valve open 6 turns. Total run time was 4 hr 5 min start to finish. I was able to pull off 10 jars. Jar #3 had a proof of 193.1 @ 75.7 deg or 189.4 proof when corrected.

A couple of notes, once I got in about 5 jars the view ports fogged in the plates and the proof dropped to 187. I think this suggests that most of the work was being done in the 2 ft packed section. I suppose it could be an area to explore in the future, but it wont do azeo, so probably not worth exploring if neutral is the goal.

Next week I will run the last setup which is 5 ft of packed which will be very close in height to the 5 plates plus 2 ft packed. I would expect that setup will pull azeo and have faster take off rates than the 5 plates/packed setup. Looking at the parent site, stainless scrubbies have a HETP of about 4" That is almost 2" shorter than the standard plate T from stilldragon. For the same height you can run packed instead of plates and it will produce a higher output and higher ABV based on the 3 ft packed vs 5 plates. Dont get me wrong, I think plates have a place for the home distiller, but it isnt for making neutrals.
Based on what I have observed so far, I would say if you want to run plates, run 2 or 3 and make a flavored product. For a neutral buy a couple of spools and run a packed column.

[bluefish_dist]

Finished the final test today. I would say the results are not unexpected. I ran 5 ft of packed column. The run time was right at about 4 hrs, collected 10 jars, ran at 8 turns open and had a collection time of 4:30 for 300ml. The proof was slightly higher than the 2 ft packed over 5 plates at 190.2 corrected. Overall this setup ran pretty well, but still not quite azeo, although it was the only setup other than the 6 ft packed over one plate to exceed 190 proof. It might have been able to get to azeo if I had kept the reflux higher and not pushed for output. I will put together a spread sheet with the results, but my take on it is you need a lot of column to truly hit azeo.

Based on what I see in the data a packed column offers a better ability to separate alcohol from water quickly given the same column height. The HETP of stainless scrubbies is smaller than the standard T's offered for sale, so you get more equivalent plates per foot of height. Packed column is also cheaper for hobby size still 2, 3, 4". What this test really showed for me is I need to test different packing material to see if there is a packing of reasonable cost that has a better HETP than stainless scrubbies. If there is something that does offer a better HETP then packing will out perform plates by a larger margin.

With that said, I think plated columns have a place on the hobby scale, but more for one and done runs of flavored products. I will continue with my normal routine of using 2 or 3 plates for Rum, Tequila, White Dog, Whiskey, and packed for Vodka.

[der wo]

Thanks bluefish,

you sacrificed a lot of time for something where we (and you too) didn't expect a surprise. Good to have a thread now with straight numbers. Probably it will linked from many threads in future.

[bluefish_dist]

I really didn't know how it would go when I started. I had wondered if 3 plates under 5ft packed was better than 1 plate and 6 ft packed. It became quickly evident that packing was more efficient. Now to test packing.

[Lowie]

Thanks for sharing your experiment with us Bluefish. Much appreciated.

[raketemensch]

Agreed, this was awesome. Nice work, man.

It’s interesting to see speed go up with ABV. That seems counterintuitive to me.