2" vs 3" Column for VM still

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Drosteo
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2" vs 3" Column for VM still

Post by Drosteo » Tue Sep 07, 2010 4:04 pm

Hi,

have been readin through multiple posts in this fantastic forum and have decided that i would be best to build a VM still.

Was wanting to know the pros and cons of going for 3" vs the 2" that most people tend to use for their column.

Also if anyone has any good plans for a VM still i would definitely appreciate a PM.

Thanks in advance

rad14701
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Re: 2" vs 3" Column for VM still

Post by rad14701 » Wed Sep 08, 2010 10:49 am

The choice to go with 3" versus 2" needs to be based on several factors...

First is cost... The price of 3" is quite a bit higher than for 2"... All of the fittings are higher priced as well...

Second is the size of the boiler you will be using to drive the column... And along with that comes the amount of heat you will require to drive the boiler...

Then you have the size of the wash that is required to charge the boiler...

And then there is the added time to get a 3" column up to equilibrium...

So, essentially, if you want to do larger runs that take longer then a 3" VM column is the way to go... But if you will be doing more smaller runs then a 2" column would be a better fit... The choice is yours...

kiwistiller
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Re: 2" vs 3" Column for VM still

Post by kiwistiller » Wed Sep 08, 2010 1:34 pm

Can you provide more detail about the wider column needing more time to equilibriate, rad? Haven't heard that before.

Also, I think it's misleading to say that a 3" will be a larger, longer run - remember it can produce theoretically twice as fast (slightly less in practice I'd expect) as a 2". Also, the difference in the columns when it comes to entrainment is quite small, so you don't nessesarily need a bigger boiler. I agree you'd want one, though.
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rad14701
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Re: 2" vs 3" Column for VM still

Post by rad14701 » Wed Sep 08, 2010 4:35 pm

Given the volume of the column it will take longer to reach equilibrium... Also, being larger, and thus requiring a larger boiler charge, runs will take longer even with a greater production rate - but perhaps not depending on the boiler charge size... You wouldn't run a 3" column on a 20 liter stock pot, for example...

kiwistiller
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Re: 2" vs 3" Column for VM still

Post by kiwistiller » Wed Sep 08, 2010 4:49 pm

rad14701 wrote:Given the volume of the column it will take longer to reach equilibrium...
Why? Can't see how diameter would effect they way fractions stack in the column. Have you got something empirical on this or is it just supposition? A link or whatever is fine, you don't need to write it out. I can see how thermal mass would mean a marginally longer heatup, but I don't imagine that's what you are referring to.
rad14701 wrote:You wouldn't run a 3" column on a 20 liter stock pot, for example...
... You could.... You'll lose a tiny bit more to column entrainment, granted, but you're talking a litre or so at max. I remember running the numbers with riku and harry on the amount entrained when you account for both vapour and reflux, it isn't all THAT much really. But I agree that you wouldn't, it would indeed be silly to build a fast still and limit yourself with a substandard boiler. like a Maserati with a 5L fuel tank....

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condensificator
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Re: 2" vs 3" Column for VM still

Post by condensificator » Wed Sep 08, 2010 10:13 pm

Drosteo wrote:Hi,

have been readin through multiple posts in this fantastic forum and have decided that i would be best to build a VM still.

Was wanting to know the pros and cons of going for 3" vs the 2" that most people tend to use for their column.

Also if anyone has any good plans for a VM still i would definitely appreciate a PM.

Thanks in advance
i'm just a first year guy, but i'll tell you what...you'd think that it wouldn't be a big step from 2" to 3", but it is HUGE! i've built a few 2" rigs, and the 3" that i'm working on right now is more than double of everything. http://homedistiller.org/forum/viewtopi ... 17&t=17062 the copper pipe and fittings are more than double in price, seems more than double in weight, double the amount of heat to solder (i use hard solder and that 3" shit sucks up heat like water on a sponge). i'm not finished yet, but i think it will end up being four times the amount of hours into it as a 2", and if i hadn't had the experience of the other 2 inchers, it prolly would've taken me even twice over that! i am super STOKED on the project, and if it give me twice as much as my current 2" rig, it will all be worth it...but be warned...if you do not already have some of the necessary skills, you are putting yourself up against it, big time. my 2 incher is more than capable of providing me with more likker than i will ever be able to consume or give away, but i have always subscribed to the "too much is never quite enough" philosophy.

good luck!

olddog
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Re: 2" vs 3" Column for VM still

Post by olddog » Wed Sep 08, 2010 10:19 pm

condensificator wrote:'m just a first year guy, but i'll tell you what...you'd think that it wouldn't be a big step from 2" to 3", but it is HUGE! i've built a few 2" rigs, and the 3" that i'm working on right now is more than double of everything. http://homedistiller.org/forum/viewtopi ... 17&t=17062" onclick="window.open(this.href);return false;" rel="nofollow the copper pipe and fittings are more than double in price, seems more than double in weight, double the amount of heat to solder (i use hard solder and that 3" shit sucks up heat like water on a sponge). i'm not finished yet, but i think it will end up being four times the amount of hours into it as a 2", and if i hadn't had the experience of the other 2 inchers, it prolly would've taken me even twice over that! i am super STOKED on the project, and if it give me twice as much as my current 2" rig, it will all be worth it...but be warned...if you do not already have some of the necessary skills, you are putting yourself up against it, big time. my 2 incher is more than capable of providing me with more likker than i will ever be able to consume or give away, but i have always subscribed to the "too much is never quite enough" philosophy.

Wait til you go to a 4"column, go apply for a loan. :mrgreen: :mrgreen: :mrgreen: :mrgreen:


OD
OLD DOG LEARNING NEW TRICKS ......

RefluxFan
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Re: 2" vs 3" Column for VM still

Post by RefluxFan » Wed Sep 08, 2010 11:04 pm

rad14701 wrote:Given the volume of the column it will take longer to reach equilibrium... Also, being larger, and thus requiring a larger boiler charge, runs will take longer even with a greater production rate - but perhaps not depending on the boiler charge size... You wouldn't run a 3" column on a 20 liter stock pot, for example...
I went from a 2 inch to a 2.5 inch column, granted the first one was a CM and the 2.5 is a VM, but my run times are actually alot quicker and my first boiler was 25litres, my new one is 96litres.
I am also using a bigger gas heater.

Long story short, I made everything bigger: boiler, column and gas heating and my runs don't take as long with alot bigger yeilds. :wink:

kiwistiller
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Re: 2" vs 3" Column for VM still

Post by kiwistiller » Wed Sep 08, 2010 11:19 pm

olddog wrote:Wait til you go to a 4"column, go apply for a loan. :mrgreen: :mrgreen: :mrgreen: :mrgreen:
OD
Yeah, or wait around for cheap bits and pieces to appear for a year or so :roll: :lol: (just need some sheet for my plates now!)
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Manback
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Re: 2" vs 3" Column for VM still

Post by Manback » Thu Sep 09, 2010 3:55 pm

How much n what thickness you need kiwi?

Kentucky shinner
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Re: 2" vs 3" Column for VM still

Post by Kentucky shinner » Thu Sep 09, 2010 3:58 pm

olddog wrote:
condensificator wrote:'m just a first year guy, but i'll tell you what...you'd think that it wouldn't be a big step from 2" to 3", but it is HUGE! i've built a few 2" rigs, and the 3" that i'm working on right now is more than double of everything. http://homedistiller.org/forum/viewtopi ... 17&t=17062" onclick="window.open(this.href);return false;" rel="nofollow the copper pipe and fittings are more than double in price, seems more than double in weight, double the amount of heat to solder (i use hard solder and that 3" shit sucks up heat like water on a sponge). i'm not finished yet, but i think it will end up being four times the amount of hours into it as a 2", and if i hadn't had the experience of the other 2 inchers, it prolly would've taken me even twice over that! i am super STOKED on the project, and if it give me twice as much as my current 2" rig, it will all be worth it...but be warned...if you do not already have some of the necessary skills, you are putting yourself up against it, big time. my 2 incher is more than capable of providing me with more likker than i will ever be able to consume or give away, but i have always subscribed to the "too much is never quite enough" philosophy.

Wait til you go to a 4"column, go apply for a loan. :mrgreen: :mrgreen: :mrgreen: :mrgreen:


OD
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loneswinger
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Re: 2" vs 3" Column for VM still

Post by loneswinger » Wed Sep 15, 2010 2:42 pm

Why not 3 inch for packing, reduce to 2 inch for T and all the workings. Not sure why this isn't done more often. From my understanding the reason for the larger column diameter is you can up the power/vapor load into the column without increasing the vapor velocity. The vapor velocity shouldn't matter in the T section or the reflux condenser or the take off valve or any of them workings. Most of the $costs$ is in these components, not in the pipe itself.

Why shouldn't this work? My first VM still was a 2 inch column reduced to 1 inch for all the workings. (The reflux condenser was built out of 1/8" tubing :D ) It was a stove top unit so I never tried to push it and always ran it slow. I wonder if it could keep up with my all gas fired 2" VM output rate....

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Re: 2" vs 3" Column for VM still

Post by JethroBodine » Sat Sep 18, 2010 4:37 pm

I think you'll find that packing a 3 inch column is going to be WAY more expensive than packing a 2 as you are filling double the volumn, and 3 inch pipe is more expensive( special order in my area) than 2". Keeping the cost down with few fittings is easy to do with a little planning ahead. One 2" tee cxcxc, one street 2" 90 degree elbow, one reducer for the gate valve and one more for the condensor. I can only get 10 ft lengths of copper tubing, so using all 2" would be more cost effective and I wouldn't have an extra 5 foot chunk of 3 inch pipe hanging around. All things considered, without knowing how Drosteo is set for finding tube and fittings cheaply, I would vote for all 2 inch.
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Drosteo
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Re: 2" vs 3" Column for VM still

Post by Drosteo » Sat Sep 25, 2010 8:45 pm

Thankyou all for your input.

I have a friend who is going to build it out of stainless steel for me. He has alot of pipe and fitings lying around as he built his own large scale commercial winery.

I probably dont want to have to have more than a 50L wash to boil at any one time. Therefore maybe a 2.5" would be the go?

I have 2x1300W elements and a 2300W element. I was thinking of putting 1 of each in the boiler to get it up to temp then turning off the 2300W and just letting the 1300W keep the temp.

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Re: 2" vs 3" Column for VM still

Post by loneswinger » Mon Sep 27, 2010 8:02 am

Drosteo wrote:Thankyou all for your input.

I have a friend who is going to build it out of stainless steel for me. He has alot of pipe and fitings lying around as he built his own large scale commercial winery.

I probably dont want to have to have more than a 50L wash to boil at any one time. Therefore maybe a 2.5" would be the go?

I have 2x1300W elements and a 2300W element. I was thinking of putting 1 of each in the boiler to get it up to temp then turning off the 2300W and just letting the 1300W keep the temp.
Those numbers sound pretty good. With 1300 Watts and a tall, well insulated column, you should be able to pull off about 1.5L per hour of 95%. Including warm up time and equalization time you should be able to run off a 50 L wash of 30% in around 10-12 hours, depending on how deep into the tails you go. A 2" column will also handle that power well if you want to go a little smaller. I think with 2.5" you could get away with powering the column at 2000 Watts if you wanted to run the takeoff a little faster like in the 2L/hr range.

If you build it with 2.5", I think you could utilize 1x1300 Watt and 1x2300 Watt. Run them both during preboil, equalize the column and bleed off the heads with the 1300. Do the hearts with just the 2300 collecting up to 2.5L/hr, then maybe switch back to the 1300 Watt toward the end of the run to make the cut to tails. This way you could shorten the run some if you cared to. My runs take closer to 16 hrs so even 10-12 hrs for me would be pretty good.

Have Fun,
-Loneswinger
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myles
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Re: 2" vs 3" Column for VM still

Post by myles » Mon Sep 27, 2010 2:14 pm

loneswinger wrote:Why not 3 inch for packing, reduce to 2 inch for T and all the workings. Not sure why this isn't done more often. From my understanding the reason for the larger column diameter is you can up the power/vapor load into the column without increasing the vapor velocity. The vapor velocity shouldn't matter in the T section or the reflux condenser or the take off valve or any of them workings. Most of the $costs$ is in these components, not in the pipe itself.

Why shouldn't this work? My first VM still was a 2 inch column reduced to 1 inch for all the workings. (The reflux condenser was built out of 1/8" tubing :D ) It was a stove top unit so I never tried to push it and always ran it slow. I wonder if it could keep up with my all gas fired 2" VM output rate....

-Loneswinger
Mine is being built with a 1.4" T in a 2" packed column for a bit of variety and to compare with the 2" / 1" combo people. I see no reason at all why a 2" vapour spliting T wouldn't work on a 3" column.

Would be an idea to work out the vapour speeds and reynolds numbers to find a good combination. I just wish I could find the time to complete my VM / CM still.

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