Does a packed column need to be vertical?

[Steve Broady]

If I have a 2” column packed with something, does it have to be vertical to work? I would assume the answer would be yes, but you probably know a lot more than I do.

The reason I ask is that I’m thinking of starting off a column with a nearly horizontal section in order to get it into a better location for my space. Is there any benefit to packing that section? And would it matter if the packing was something like copper mesh which could conduct heat to the column walls rather than something like lava rocks? My guess is that liquid would just run down the bottom of the tube and do virtually nothing useful on its way back to the boiler. But I figured I’d at least ask.

[contrahead]

"If I have a 2” column packed with something, does it have to be vertical to work?"

I would ASSume that the best answer to your question is, certainly not. The most important consideration for a reflux column is the intermingling and exchange between hot new vapor and the rerunning reflux which is liquid and less hot. Surface area of the packing, temperature exchange and gravity are all crucial to the concept of cycling reflux.

A nearly horizontal packed column should have at least some slope so that the liquid reflux can run back to the boiler. But it would seem that such a scheme should be less efficient that a vertical column, because of the reduced gravity factor alone. However it also seems that such a scheme could be compensated for by increasing the surface area of the packing and lengthening the travel distance of vapor.

A comprise might be to fix the column at a median angle, say 45 degrees or so. That way the gravity problem is partially satisfied; but also, the height of the still can be reduced, the heavy weight of the still's top might be more easily balanced or possibly everything above the boiler could be built freestanding. (Column, condenser, hoses and valves – anything above the boiler fixed to and supported by a strong and braced stand, rising from the floor – attaching to the mouth of the boiler only by union or tri-clamp).

[cob]

Your question could be prompted by 1. a height problem. 2. a distance problem.

#2. could be solved as simply as a longer lyne arm, or takeoff tube. #1. not so much.

[Yummyrum]

Not sure what angle you are thinking about , but I did a little experiment here

I’d say pack it and see . You may be surprised .

E83E2390-B5D1-4DE4-B311-173B3B8CAF96.jpeg

[Steve Broady]

Your question could be prompted by 1. a height problem. 2. a distance problem.

A little bit of both, actually. For the time being, I am restricted to using a relatively small 8 gallon still on the kitchen stove. While I have 9’ ceilings, I would prefer not to need a ladder to reach the top of a tall column. But the bigger issue is that the microwave is above the stove, and if I have a column coming out of the center of the still, it blocks access. Since I have to be considerate of the other people in the house (my wife is quite supportive, my toddler not so much) I am trying to find a way to avoid that problem. The solution so far has been simple- pot still that’s carefully built to just fit beneath the microwave door.

As for the angle, I’m thinking nearly horizontal. I would run it from the center of the still to fit in beside the microwave, then turn vertical at that point. Obviously, I could just leave it open and start the packing in the vertical section, but I was curious to know if I could make some practical use of the 18”-24” horizontal run as well.

[Steve Broady]

I should note, all of this is theoretical at this point. I’m cogitating on a new build if I can come up with a design I like.

[Demy]

Not sure what angle you are thinking about , but I did a little experiment here

I’d say pack it and see . You may be surprised .

E83E2390-B5D1-4DE4-B311-173B3B8CAF96.jpeg

I remember reading this experiment .....

[RC Al]

Move the microwave?
Just when stilling?

I think horizontal is very different to what yummy did, you would need to support it well.

Have a look at offset column builds, perhaps a small thumper on the next bench at the right height with a p trap return drain.

What sort of stove? If its electric you will most likely have dramas with the element cycling, especially with a reflux vs a pot.

Maybe find an appropriate portable electric element and put it on the floor?

[captainshooch]

Not sure about if it will work or not but in the past flooding and channeling have been issues that in my opinion makes vertical better, or you will certainly encourage channeling which defeats the benefit of the packaging.

[Steve Broady]

Move the microwave?
…
What sort of stove? If its electric you will most likely have dramas with the element cycling, especially with a reflux vs a pot.

The microwave is built in, so moving it is technically possible (I’m
The one who put it there in the first place, after all), but not practical.

I hadn’t thought about the element cycling. Yes, it’s electric, so that might be a deal breaker right there. Now that you mention it, I’ve read about others having issues with that. Event, I’ll be putting an induction cooktop in, but that means building cabinets, which takes time away from ‘stilling!

Might be time to consider other options.

[Stonecutter]

What sort of stove? If its electric you will most likely have dramas with the element cycling, especially with a reflux vs a pot.

Maybe find an appropriate portable electric element and put it on the floor?

+1

[shadylane]

A while back there was a post about a column that was almost horizontal and rotated.

[bcook608]

I would bite the bullet and go with the submerged element and controller. You can even build your controller so it plugs into your stove outlet!
If your wife is supportive, maybe she won't mind the dryer being unplugged while you're doing your run. Then you can leave your microwave and stove open altogether!

Ever since I switched from my propane burner to my electric still, I've been amazed at how much more responsive it is and how easy it is to still wherever I want to without having to worry about flames and excessive heat. Just remember to insulate your boiler well otherwise you're just making one big radiant heater. However, that might not be such a bad idea coming into the winter months

[IAmPistolPete]

Just to be clear, [especially for newb/future readers] are we talking about a true packed reflux column? or packing the riser/lyne arm of a pot still?
Kind of a big difference...

[Stonecutter]

Just to be clear, [especially for newb/future readers] are we talking about a true packed reflux column? or packing the riser/lyne arm of a pot still?
Kind of a big difference...

Just to add to that. Without reflux you’ve only got a pot Still whether you have packing or not.

How are you controlling reflux Broady? CCVM, CM, VM? Hopefully this hasn’t already been asked in this thread.

[Steve Broady]

What I have right now is a pot still. I’m just thinking about the next step, which seems like it ought to be some kind of reflux design. So, the short answer is yes, we’re talking about reflux and I haven’t decided the best way to control it yet, though a combo LM/VM design is appealing to me at the moment. However, as I mentioned above, it seems that I might need to go back to the drawing board.. I have a couple other ideas that might be worth exploring as well. Time will tell. In the mean time, I’m very grateful to anyone willing to share their experience and to teach others.

[Stonecutter]

Well, a theoretical or hypothetical stilling design that’s not yet on paper is going to be hard to critique even for the most experienced members
Looking forward to seeing which path you take. Like what’s been said above. I’d get different equipment so that you can mobilize your rig.
If you’ve got an existing setup that makes a decent drop there’s nothing wrong with working that setup for all its worth. Especially If money and space are tight just work with what you’ve got to make the best you can until you can drop the rig onto the floor. You’ll build up stock and experience.
That way you’re not trying to reinvent the wheel for a reflux still design later down the road.

[elbono]

I’ll be putting an induction cooktop in

I think some of those also pulse the heat on and off.

They are really snazzy and have many variations available. I saw some that work through a granite countertop when I was remodeling my kitchen. Just make sure what you buy doesn't pulse the power if you want to run a still on it.

[Steve Broady]

Well, a theoretical or hypothetical stilling design that’s not yet on paper is going to be hard to critique even for the most experienced members

That’s certainly fair! I guess I ought to be more clear in my questions. When I tackle a project, I like to make sure I understand most, if not all, the reasons that go into the decision making process. Tried and true is very useful as a template, and sometimes it’s done that way because it’s the best way. Other times it’s done that way because it’s always been done that way. So when I start coming up with ideas that are non-conventional, I try to understand why the would or wouldn’t not work as well. And when I can’t do that, I try to find someone who can help me understand.

Which is a long winded was of saying that I don’t know what I’m doing, so before I spend a bunch of time and money making stupid mistakes, I figured I’d ask some more questions.

[Renhoekk]

Well let me put it this way. Regardless of what you do with your column, your vapours are going to do their damn best to rise vertically, and the falling reflux is going to do its best to go down vertically.

A vertical column allows the rising vapour to have optimal interaction with the falling liquid, and become more and more enriched as it moves up the column.

A horizontal column will just smoosh everything together along its length. You may even find that a large amount of vapour recondenses and falls back into the boiler without travelling very far into the column.

If you’re pressed for vertical space, choose packing that has a very large surface area to get the most bang for buck from a shorter vertical column.

[PLAYMP]

Not sure what angle you are thinking about , but I did a little experiment here

I’d say pack it and see . You may be surprised .

E83E2390-B5D1-4DE4-B311-173B3B8CAF96.jpeg

One thing I haven't seen mentioned is I think there is a little bit of safety concern here to a sloped column. My set up is really similar to Yummyrum's
VM above but if that slope was any more severe I'd be worried about mine tipping over part way through a run as the boiler loses weight

[SDEngr1]

If not completely vertical the distillate will tend to run down the low side via gravity and defeat the entire process in my opinion.