LM Nixon-Stone Offset Rebuild

[rparody]

So after a discussion in another part of this forum, I have discovered with the help of some educated people that my current setup is not really creating the azeotrope needed to separate out all the different volatiles that I get when I am distilling. My current build's column was only 2' long with 2" diameter copper pipe. And this supposedly is helping to cause smearing. So before I began on my plans for the rebuild, I just wanted people to know what my last Nixon-Stone Offset setup was.

So onto bigger and better things. I have made up some drawings. I've done the scaling. I have all of the copper parts. All of the tools to solder this new plan up. So I guess I am all ready to go. But I think before I do it, I want to get some people to look over some of the details and tell me if this setup ultimately is going to give me some clean product if fermented/distilled correctly. I want to break down each component of the setup so everyone can see the stats. And just a side note... all of the pieces I am breaking down are going to be modular, so I can take those pieces apart for cleaning or changing out to a different type of still. These parts are all separated by 2" MNPT and 2" FNPT adapters for easy disconnect.

Boiler:

The boiler is a 15 gallon SS Pot. Modified with a 5500W element in the bottom. I am not changing anything about this except for the gasket to seal the lid, which right now is some type of vinyl. Gotta check out PTFE or just use the dough like so many probably do.

Condenser:

The condenser plan is a 1' long shotgun condenser. The outer shell is 2" copper pipe and the inside is (8) 3/8" pipes running through it. Ordered some special rigid straight 3/8" pipe just for this. Love the amount of surface area making contact vs. 1/2" or 3/4". Anyhow. This was going to be longer (2' long), but unfortunately with the setup needing to be in the house near the stove, the ceiling is 84" tall, and anything over a 1' condenser will not clear. From what I read (or by theory)... this should be plenty to knock down under 2kW of power being thrown at it. My standard has been to run the still at 1.6kW when doing a spirit run. So this should suffice, until I get a garage in our new house we are looking for. Then I can make this bigger.

Column

The column is a straight 2" Pipe that is 3' Long. This combined with the Nixon-Stone Offset head should give a total packed column (with copper scrubbies) for a total of around 40" of refluxing. My understanding is this is the money for creating the fractional still. Everything should be at peace and it should create the layers needed to separate the volatiles etc...

Nixon-Stone Offset Head

This is the core of the operation. It is all 2" piping (there is no reduction). Coming from the column, the vapor enters a 2" copper T. Above the T is where the vapor monitoring temperature gauge is. When the vapor makes the 90 turn it travels to another T. That T then goes up to the condenser or down to the collection/reflux vales. The reflux path goes back over to the column separated by a 3/8" needle valve and the collection tube just straight down with another 3/8" needle

Drawings:

Boiler Drawing v1.jpg (14.24 KiB) Viewed 3366 times

Column Drawing v2.jpg (14.17 KiB) Viewed 3366 times

Please take a look at these drawings and let me know your concerns. Thank you!

[Odin]

Your packing choice may be crucial. For SPP ... if you push 1.6 kW in it, not sure if it is going to be enough. 2 to 2.5 kW is better.

Odin.

[rparody]

Your packing choice may be crucial. For SPP ... if you push 1.6 kW in it, not sure if it is going to be enough. 2 to 2.5 kW is better.

Odin.

I think with any new setup... I will have to play with the power and see where I am getting the best results. I have never operated a 3 foot column before, so maybe 1.6kW will not be enough. We shall see. I definitely do intend to pack it full with copper scrubbies for all 40 in. Thanks for the feedback!

[still_stirrin]

You may try scoria (lava rock) packing. I’ve heard it is very efficient for reflux. And is is almost “dirt cheap”....you can get a big bag of it from any landscape shop for a few dollars. Copper scrubbies or copper mesh wil not be cheap, especially for a meter tall column. Glass marbles aren’t too expensive either although not quite as efficient as the scoria.

Also, insulating the column will help with the reflux cycling. The vapor’s heat stays inside the column allowing better heat transfer to the falling condensate.

Good luck with your project.
ss

[OtisT]

Hi rparody

I have a few personal observations for ya.

I’m surprised to see you using a lot of 2” NTP connections. Hell, I have never seen one that big. Maybe I am miss reading the diagrams you posted. (Quite possible). If you have them, they must be damn heavy. This may not be the best modular solution long term. For starters, using copper threads it will be a challenge to get everything lined up right, and over time this alignment will likely move. Assembly and disassembly will be a PITA, using tape and you will be marring up the copper over time. Leaks will be a challenge. I’m not sure what else other than ferrules/tru-clamps for something that size. Couplers with a lot of paste? Do they make a 2” union fitting?

Make sure the drain from the LM head drops reflux directly in the center of your column for proper fractioning. Either by tube positioning or possibly a centering ring.

You should be able to get good separation in a 2” x 36” insulated column if you go slow enough and watch the temp. You called this being “at peace”. I like it.

All sorts of packing options already discussed above. I’ll just add to the packing conversation that I use just shy of a full pound of copper mesh packing to fill my 2” x 36” column for fractioning. It seems to be a good density for my needs. If the 1 lb role of mesh is 5” wide, I cut the role into 8 equal sized pieces. Roll 7 of those pieces up to pack gently into the 2” column for 35” of packing. I use the last role in my sight glass when a little extra height is needed or for scraps to wrap with my coil condenser.

Be sure to insulate that column when fractioning.

I wish you good fortune in the cuts to come. Otis

[Yummyrum]

Its no going to work as drawn .
It is all wrong around the reflux collection and return bit .

The way you have the valve positioned is known as Reverse Liquid Management Control or RLM where you control the amount of reflux returning to the main packed column and the excess overflows as collected spirit .... but ... because the collection tube in your diagram is lower than the return line , all reflux will exit straight out the bottom and none will be returned as reflux .

You might be better off putting the valve in the output line . This will be the more common LM method . You adjust the output valve to let a dribble out and the rest backs up and overflows back to the packed column . However it is best if you add a pigtail or “U” in the return line to act as a fluid lock to let the reflux flow back but stop the vapour in the main column taking a short cut through it .

If you do stick with your present method you need to have the takeoff (output ) tube higher than the relux return outlet tube.... as simple as inserting it about 1/2” into the bottom cap .... so the liquid can backup behind the return valve before exiting out the outlet . It would also be wise to put a fluid lock on the output in this case .


Also I would strongly recommend forgetting about the NTP connections and using the pretty much standard triclamp connections as Otis said

[Saltbush Bill]

Listen to Yummy , he knows his shit when it comes to reflux stills

The boiler is a 15 gallon SS Pot. Modified with a 5500W element in the bottom.

This bit has me worried , I take it you will be using a controller with this.?

[rparody]

I’m surprised to see you using a lot of 2” NTP connections. Hell, I have never seen one that big. Maybe I am miss reading the diagrams you posted. (Quite possible). If you have them, they must be damn heavy. This may not be the best modular solution long term. For starters, using copper threads it will be a challenge to get everything lined up right, and over time this alignment will likely move. Assembly and disassembly will be a PITA, using tape and you will be marring up the copper over time. Leaks will be a challenge. I’m not sure what else other than ferrules/tru-clamps for something that size. Couplers with a lot of paste? Do they make a 2” union fitting?

Hiya Otis! Thanks for getting back to me on this. Yes... I have used the NTP connections before to connect up to my boiler. The only problems I have had with them is if you dont use the correct vapor sealing tape, it will leak. But other than that... Generally I have not had any issues. I got them for fairly inexpensive prices (less than 20 each) so.. I just figured I would do it up that way. I will definitely let you know how it all works out. If it is a major problem, then I suppose I can just de-solder them and put the tri-clamps in place. No worries there. Not too concerned about the lining up either... after a certain point (but before the threads start binding up) you can get pretty good sealing for a total 360 rotation. So also, no worries there. (Or at least, my tying the old still into the boiler had that kind of play. So we will see). And yes! They do make 2" unions. And they are like 140 dollars a piece. NOPE!

Make sure the drain from the LM head drops reflux directly in the center of your column for proper fractioning. Either by tube positioning or possibly a centering ring.

Are you saying to make sure the 3/8" pipe sticks in far enough to be in the middle of the diameter of the 2" pipe? Or are you saying that the actual reflux pipe is up too high on the column and should be much much lower than it currently is? I assume that you mean it should be pushed in further than just being right at the opening of the hole into the 2" pipe. Because then the returning fluid will just drop down the side instead of drip directly in the middle. Let me know which one you mean.

Be sure to insulate that column when fractioning.

My last column was insulated, and this one definitely will be as well! Check check and check

[rparody]

Its no going to work as drawn . It is all wrong around the reflux collection and return bit .

Hiya yummy rum. Well this is rather disheartening to hear. But I also think that maybe you have misinterpreted the drawing. Let me explain further. Or maybe I am not interpreting what you are writing correctly. So let me do a little explaining.

The way you have the valve positioned is known as Reverse Liquid Management Control or RLM where you control the amount of reflux returning to the main packed column and the excess overflows as collected spirit .... but ... because the collection tube in your diagram is lower than the return line , all reflux will exit straight out the bottom and none will be returned as reflux .

I am confused as to what you mean here. There is a 3/8" valve on both the return line (for the reflux) and on the collection line (the one dropping straight down). So initially when I begin, I will pretty much close off the collection line completely and then this will allow liquid to build and then flow into the return line and back into the column. This will give me the refluxing I am looking for. Then after the equilibrium is all set up, I can crack the collection valve open slowly and start collecting the foreshots/heads. Am I missing something?

You might be better off putting the valve in the output line . This will be the more common LM method . You adjust the output valve to let a dribble out and the rest backs up and overflows back to the packed column . However it is best if you add a pigtail or “U” in the return line to act as a fluid lock to let the reflux flow back but stop the vapour in the main column taking a short cut through it .

So yes, as I stated in the previous quote, there are two valves. that should remedy what you think is the problem. As far as the vapor possibly getting into the return line, I guess I could add some kind of vapor lock. However, I just assumed that once the reflux got going, the vapor would no longer take that route because there would be liquid in the return line and it would be a more "resistant" path to follow and therefore would not go up the return line. Now I might be thinking completely wrong on that and perhaps there is a better more efficient way to stop this from happening (like this U that you speak of). I guess my question is, is it really that big of a deal for that vapor to go up the return line? The return line is up pretty high, so I would think it would be fine (since the lighter volatile are already up high to begin with). Not too much smearing should happen if a little vapor gets splashed together with the returning liquid. Correct me if I am wrong.

If you do stick with your present method you need to have the takeoff (output ) tube higher than the relux return outlet tube.... as simple as inserting it about 1/2” into the bottom cap .... so the liquid can backup behind the return valve before exiting out the outlet . It would also be wise to put a fluid lock on the output in this case .

I think this is also solved by the fact that there are valves on both the return line and the collection line.

Also I would strongly recommend forgetting about the NTP connections and using the pretty much standard triclamp connections as Otis said

And as for the NPTs... I am willing to give them a shot like I have done before. I had no leaking issues and as long as you use the Vapor PFTE tape, it hasn't given me any issues. But I could find out it all sucks and I will gladly switch to the tri-clamps.

[rparody]

Oooooopppsss! I see the problem yummy! I didn't bring another call-out line to the other valve! That was my fault. There definitely is two 3/8" needle valves on both lines, I shall correct the drawing and re-post.

Edit: Yeah, when i shrink the size of the photo down to less than 800x800... that line that is going over to the collection valve completely disappears. I just tried it again, and the line did not appear again. So I am not sure how to fix that issue to show you yummy

[rparody]

This bit has me worried , I take it you will be using a controller with this.?

Oh yeah!!! I didn't say anything about the controller. Yeah I have a pot resistor type controller. It works just great! Gets a little warm during the heat up at 5.5kW though. But after I back it down to around 1.6kW it resumes just lightly warm to the touch temperatures.

[Yummyrum]

Arrh Yes . I can now see that you have a valve on the outlet . It wasn’t labeled and my blurry eyes didn’t realise that was what it was . So yes you have it correct

I still don’t see the need for a valve on the return line . It won’t hurt so long as the internal bore does not impede reflux flow but it won’t really be needed either .

My comment about vapour blowing back up the return line was based on some experiments I did a few years ago where the reflux was not flowing steadily but coming out as spurts which upset the whole still making it run erratically .
If you read back in your other thread you will find still-stirrin also recomended the same thing . Its not just my thinking .

[rparody]

Arrh Yes . I can now see that you have a valve on the outlet . It wasn’t labeled and my blurry eyes didn’t realise that was what it was . So yes you have it correct

I still don’t see the need for a valve on the return line . It won’t hurt so long as the internal bore does not impede reflux flow but it won’t really be needed either .

My comment about vapour blowing back up the return line was based on some experiments I did a few years ago where the reflux was not flowing steadily but coming out as spurts which upset the whole still making it run erratically .

I guess the ONLY reason I even put the valve in there was just in case I wanted to make an overly rich pot still hahahahhaha. So I could shut the reflux down completely and let it run wide open out of the collection. Maybe killing two birds with one stone I suppose.

And I guess I dont understand this U loop back thing quite clearly. Inside of the line going across, you make a U shape underneath it so liquid can pool up? Maybe it would help if I could see a picture?

[Yummyrum]

You got it , just about a few inches long . Imagine the thing under a kitchen sink . Just a U not an S

Regarding the valve on rhe return line for Pot mode , yes that makes sense

[rparody]

OOOOHHHHH. You mean get rid of the valve completely and shape the return line into a U shape. I think I see what you mean. But wont the vapor just push through it regardless whether its in a U or a straight pipe? I think that is the part i'm having a hard time grasping.

[Yummyrum]

The weight of the liquid in the U stops the vapour pushing through .

If tou have looked at the flute builds you will see they all have a cup or U at the bottom of rhe down comers . It doesn’t take a lot of liquid to stop the vapour.
Some of those Flute fluid locks are only about 3/4” long but its enough to hold back the pressure thats pushing up through the plates above .

[rparody]

Physics. Love it. I wanna re-draw the drawing real quick and get the blessing before I actually build this. Thanks for the info Yummy!

[rparody]

Alrighty! This is what the new VM head will look like. No valve (So I guess I have to build a pot still head now for sure hahahhaha) Tell me what you think.

[Yummyrum]

[rparody]

Game on! I am gonna work on this over the weekend! (I just priced out those ferrules and Tri-Clamps.... wooooooooo pricy)

[Kindafrench]

Keeping the U-part as small as possible, keeps smearing in a lower range. As far as I understood. I just put a piece of spiral bent copper cable in the reflux line, so the reflux flow is disturbed and wavy. Don‘t know yet if it works. If not, I pull the spiral out of the tube again or change the spiral design. It‘s a small playground in there. Maybe I worry to much about it.

[Kindafrench]

I just put a piece of spiral bent copper cable in the reflux line, so the reflux flow is disturbed and wavy. Don‘t know yet if it works.

Well, it didn‘t have any visual effect, so I removed it. Should stay longer in the KISS area and not trying to overengineer things.