First time using Plates, question about PRV

[Jtruluck]

Hey Gang,

I am adventuring off into the world of bubble plates and I am about to run my first vodka mash on a 3 inch open column still. Little context for my still:

Standard Keg still with a 2 inch sanke fitting and a 2" to 3" expander, 2x 2000w elements on 2" tri clamp fittings, 1x 2" thermometer on Keg. 6" offset fill port on top, 2" Drain port with 90 and a 2" valve to 3/4" barb fitting drain. I have recently Added 4x 3" dendrod Glass sight glasses from amazon and made three, 3", 3 cap bubble plates. Image below if the embedding works.

My questions is: Now that I have gone from an open vapor system for whiskey and I have added plates, is there are concern for vacuum and pressure build or should I be ok to run a 14 gallon batch in the keg still without needing a relief valve? I was hoping to run this weekend as I have 30 gallons of vodka mash in my fermenter but want to make sure I dont make a stupid mistake in the process.

Advice would be appreciated.

[Stonecutter]

No PRV needed. The system is still open as long as you’re not plugging up your final condenser.

Good luck. There’s bit of a learning curve.

[Jtruluck]

Awesome! Thanks @stonecutter This was my understanding as well but just wanted to sanity check with people who have experience.

[Stonecutter]

I hear ya there. My whole existence is one big sanity check
I have very limited running experience on plated columns.
Picture didn’t come Through. I suggest a needle valve on your pre-condenser Water output.

[jonnys_spirit]

+1 on Stoney’s suggestions. Also may want to consider a packed column to get more HETP’s for your height. I think vodka distilleries use 20+ plates.

Cheers,
-j

[Jtruluck]

The pictures worked if I opened them in new tab. Edited the post a few times but gave up when I realized that the website wasn't working with the embed codes. I will dig into that more.

As for the amount of plates, I know its low. I have between 30 and 32 gallons of wash and my intention is to run two low wine runs of 13 gallons down to 5% and then run the final 6 gallons plus all low wines in a separate run through the 3 plates. I'm hoping for roughly 85 to 87% efficiency and ~ 175 to 180 proof off the still in the hearts. I'm considering this 5 distillation counting the low wines as 1 run, then the run with 3 plates being 4. I also have copper mesh inside my reflux condenser as its a 3" copper pipe with a water jacket but there are no restriction tubes so I'm using the copper mesh to transfer some thermal knockdown power as well as further increase the interaction of vapor. And water.

But I have a 4th sight glass and could make a 4th plate in the future if I don't meet my expectations. I am leaving it clear this run because I'm pretty confident I will puke trying to get the balance of power and water right even with butter so leaving an empty sight glass is to my benefit for round 1.

Regarding water, I have 2 pond pumps, with two flow control valves and a cooler with a window AC chiller for water temp control so I will be able to dial those in separately.

[Yummyrum]

We recommend using the attachment method of including pictures .
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[Jtruluck]

@yummy Thanks for the walkthrough on the photos. Super helpful!

[Stonecutter]

Your heating element seem awfully high. Is there a reason you decided to bring them so high up on the keg?

If this has already been addressed in another thread just let me know and I’ll STFU

[Jtruluck]

All in, it comes down to the fact that I wasn't 100% sure what I was doing and I wanted to play it safe.

So Element 1 is the lower element, it is the element that is always on, element 2 is the higher element. I set the elements up so that I can fairly evenly heat the keg without interfering with each other. (this is my first build so I wasn't sure if it would affect the taste by having a big hot spot at the bottom with two elements and natural radiant heating towards the top) I determined being able to evenly heat the whole keg was a better plan but didn't want to go all the way up so the element was out of the wash. Once I get the keg up to temp, I shut off element two and can maintain and build temp in the kettle with just 1 element. This gives me control by slowing the incline of the temp but takes a little more time. I'm patient, I can handle that. I also didn't know if I had some carry over grains from the fermenter, if they would settle at the bottom or float around the keg so I left some room so the elements didn't get covered and burn stuff.

It is also very unusual that I run a batch smaller than 8 or 9 gallons. 10 gallons is the bottom of the second ring so as long as I have roughly 8 gallons in the tank my elements are covered for initial heating. As the vapor passes, I need less power and can run with 1 element no issues. I could run a single element and have enough heating potential for a full run if I needed too but why make a little when you can make MORE! I also have a Still Spirits air still that I could use if I wanted a smaller batch that wouldn't work as well but would be functional.

If I wanted to do it all over again, i would center the 6" port on top and use a 6" to 4" reducer but I'm pretty happy with the burner placement. I might take element 2 down a little but not much. What I have found is that by the time I'm at 5% on a low wines run of 12 gallons, I'm still above element 2 even though I'm not running power through it.

[Setsumi]

All in, it comes down to the fact that I wasn't 100% sure what I was doing and I wanted to play it safe.

So Element 1 is the lower element, it is the element that is always on, element 2 is the higher element. I set the elements up so that I can fairly evenly heat the keg without interfering with each other. (this is my first build so I wasn't sure if it would affect the taste by having a big hot spot at the bottom with two elements and natural radiant heating towards the top) I determined being able to evenly heat the whole keg was a better plan but didn't want to go all the way up so the element was out of the wash. Once I get the keg up to temp, I shut off element two and can maintain and build temp in the kettle with just 1 element. This gives me control by slowing the incline of the temp but takes a little more time. I'm patient, I can handle that. I also didn't know if I had some carry over grains from the fermenter, if they would settle at the bottom or float around the keg so I left some room so the elements didn't get covered and burn stuff.

It is also very unusual that I run a batch smaller than 8 or 9 gallons. 10 gallons is the bottom of the second ring so as long as I have roughly 8 gallons in the tank my elements are covered for initial heating.

As the vapor passes, I need less power and can run with 1 element no issues.
I do not follow you here. To me as alcohol reduce in the kettel you need more power... Not that it matters sonce you actualy want tails and water to stay in the pot, but I would not reduce power.

I could run a single element and have enough heating potential for a full run if I needed too but why make a little when you can make MORE! I also have a Still Spirits air still that I could use if I wanted a smaller batch that wouldn't work as well but would be functional.

If I wanted to do it all over again, i would center the 6" port on top and use a 6" to 4" reducer but I'm pretty happy with the burner placement. I might take element 2 down a little but not much. What I have found is that by the time I'm at 5% on a low wines run of 12 gallons, I'm still above element 2 even though I'm not running power through it.

[Jtruluck]

Yeah, I kind of combined two thoughts here. I was thinking about low wine runs where you are purposely choosing to evaporate water with the distillate by going low into the percentage of ABV. As the volume of water comes down, naturally your heating is more efficient and you don't need to add additional heating. That being said, as I read it back, it sounds like I'm saying once the vapor starts I decrease the temp. That is not the case. I don't have any issue taking the still from 160 to 190 degrees on 1 element without scorching so between ~160 and ~190 increasing power is necessary as you aren't evaporating much of the water of the mash.

Still learning how to explain all of these concepts, kind of like a new dictionary of terms and science.

[haggy]

J,

I have done some research and posted some information on bubble cap columns. Check out page 2 of this topic:

viewtopic.php?t=88352&start=30

One thing you have to watch is flooding. If you use 2000 watts or less heating, you should be ok at 20% abv low wines in the pot. If you have procaps, they are more forgiving. The vapor velocity through the procaps is lower. Weeping is not a problem with bubble caps.

There is an effect of the pot abv%; a higher abv will tend to flood at lower pot watts. Attached is a chart, derived from some posted run data, showing this. The middle curve is for 3" bubble caps, standard purchased bubble caps are used, three to a plate. If your three caps are standard, then running low wines above 25% pot abv at 2000 watts may be close to flooding. So run only the lower heater element and control the watts used.

____________________________________

Then there is the water jacketed defleg condenser you are using. Not a standard shotgun condenser. The wire mesh in there may help keep the vapor from blowing through, that is a new to me. Be sure to control and measure your cooling water flow rate and cw temperatures in and out. I hope the condenser is efficient.

You have a CM type plated reflux column. The cooling water flow rate will determine how much of the vapor up the column is condensed and falls back as reflux, and the rest will pass through and be your product flow. Try to find the cw flow rate to give you about 1 L/hr product rate if you want a high product abv%. This will give a high reflux ratio. Run at 2+ L/hr and a lower reflux ratio if you want a lower ( about 90% ) product abv% and more flavors carryover.

Maybe you know all this stuff, but I put it out there since you are new to HD.

haggy