Vapor in Column Backflow

[ThatDrunkenBird]

I have a consistent problem with vapor traveling from my boiler to my column via the return pipe. There is no P-trap on the return or downspout in the boiler. The vapor causes flooding in the lower plates and oddly enough plate 7 of my DYE 16 bubble plate column. Because of this I have to constantly drain certain plates and this throws the entire system off and effects my collect rate, temp and proof. I have, through a lot of babysitting, chainsmoking, hairpulling and valve manipulating, gotten the system to run smoothly without flooding any plates. However, I feel like a downspout in the boiler or a P-trap just outside the return line would immediately remedy these issues. 

Does anyone have a system that also lacks a downspout or vapor trap? How do you prevent vapor from creeping up the return?

[Brian]

Are there two paths to the column....1) for vapor and 2) for condensed liquid being returned to the pot?

[Brian]

if the liquid return path is above the liquid line in the pot, both paths could be feeding vapor....

[ThatDrunkenBird]

1 hour ago, Brian said:

if the liquid return path is above the liquid line in the pot, both paths could be feeding vapor....

This is exactly what is happening. I believe a downspout is required to fix this.

[Brian]

my pots had a return well into the pot....the path was up through the helmet and over to the bottom of the column....the liquid from the downcomers draining out of the very bottom of the column and the vapor input 3-4 inches off of the very bottom of the column.....so when running the "seal" was the liquid in the bottom of the column...

What is the diameter of the return to the pot?   ru not doing something like mis-configuring the valves right?  so another silly question: did the manufacturer commission your still....has it been wonkly from day one?

If you have a grain in mash the return could be plugged with solids from previous runs and not allowing a return...

 

 

 

[Brian]

is it possible you are driving it too hard and not allowing for the entire column to stabilize or the defleg is too cold and rejecting too much product and flooding the plates?....happen to have a laser temperature gun to check temps of plates as vapor goes higher and higher?

[whiskeytango]

3 hours ago, ThatDrunkenBird said:

I have a consistent problem with vapor traveling from my boiler to my column via the return pipe. There is no P-trap on the return or downspout in the boiler. The vapor causes flooding in the lower plates and oddly enough plate 7 of my DYE 16 bubble plate column. Because of this I have to constantly drain certain plates and this throws the entire system off and effects my collect rate, temp and proof. I have, through a lot of babysitting, chainsmoking, hairpulling and valve manipulating, gotten the system to run smoothly without flooding any plates. However, I feel like a downspout in the boiler or a P-trap just outside the return line would immediately remedy these issues. 

Does anyone have a system that also lacks a downspout or vapor trap? How do you prevent vapor from creeping up the return?

When you say "boiler" are you talking about the still kettle or the actual boiler that is providing steam to your still?

 

[ThatDrunkenBird]

3 minutes ago, whiskeytango said:

When you say "boiler" are you talking about the still kettle or the actual boiler that is providing steam to your still?

 

The Still Kettle

[whiskeytango]

Ok so there is no down tube inside the still kettle that pushes the reflux form the column back down into the wash? There usually is a p trap at the bottom of each column and a down tube into the kettle. 

 Have you contacted the manufacture? 

[JustAndy]

I've had a similar problem with a Kothe 2-column still at a place I occasionally work. The return pipes from the bottom of each column to the still kettle/boiler don't have a p-trap, valve, or flapper. Inside the still kettle, the return pipes are only about half-way down, meaning they are not submerged in liquid if the liquid level in the still drops below about 275 gallons (in a 500 gallon still). As soon as the liquid level drops below the return pipe, both columns begin to fill with vapor which is problematic if trying to bypass the columns or just use 1 column.    

[HedgeBird]

It blows my mind that professional built stills might not have a functional trap at the bottom of the column and or the plate deactivation drain line.   

Sounds like you just need to extend the line from the drain to almost the bottom of the kettle (so it will always be below the mash/wash level) or just add a J pipe to the drain line. 

What type of trap is on the bottom drain/down-comer of the first column plate above the kettle?  Assuming that trap is working and you dont have vapor pushing into the overflow from the first plate, then you have an example of a trap you should be able to duplicate and add to the drain line.

If you install a J pipe trap, just make sure to pre fill the trap with water before your first run after its installed.

[Brian]

in the bottom of my columns the downward liquid flow seals the down of the column which then drains from near the bottom of the column this "backup" functions as a kind of trap with separation from the in flow of high temperature vapor.....the tube returning to the pot was not uncovered.....

[Southernhighlander]

We use both a dip tube in the still pot and P traps at the bottom of each offset column to keep back flow from occurring.  A J tube can be used in the still pot instead a dip tube, but I think that a dip tube is more of a sure thing.   There are other design flaws that will cause columns to flood.

[Southernhighlander]

We use both a dip tube in the still pot and P traps at the bottom of each offset column to keep back flow from occurring.  A J tube can be used in the still pot instead a dip tube, but I think that a dip tube is more of a sure thing.   There are other design flaws that will cause columns to flood.

[ViolentBlue]

a p-trap is helpful, but there needs to be sufficient height separating the column bottoms, P-trap and fluid level of the boiler. otherwise you wont have enough head for gravity to do its thing and overcome the micro pressures in the kettle.  12" of height difference between kettle fluid levels and the bottom of your column only gives you a gravity/pressure difference of 0.375 PSI. this is well within the range of pressures you can build in the kettle, even with an open vapor path. Many of the newcomers to the equipment market are using 12" or less height difference, realistically 24" or more would be ideal, but then height becomes a concern.

throw in Dual columns, and your troubles double.

 

individual plate flooding is another issue, it can either be bad plate design, or a combination of running too much heat and too much reflux, in which case back off on the heat, back off on dephlegmater flow and you will have the same results out of your parrot with fewer column flooding problems.

Edited December 4, 2017 by ViolentBlue
clarifying with math

[Southernhighlander]

Violent Blue 

 

Calculating the total water column using the liquid level above each plate and accounting for the pressure differential between the columns, I come up with a minimum height and then I raise the offset columns an extra 3" to 8" above that.  However, we can now set the bases of our offset columns within 8" of the floor, for those Vodka System customers who have very little vertical space.  Also we can run through up to 3 columns with the same efficiency as a single column with the same number of total plates, no problem.  We have 0 flooding issues with these designs.  Have you seen Corson's designs?  There are like 4 different reasons that their columns flood that I can see.    The plate design is totally weird.  It's like they saw a picture of a German single bubble cap design but they didn't understand it and built it wrong.  16" plate with 1 down comer with a 1/2" ID.  Through put on that 16" plate appears to be less than my 8" plate.

[ThatDrunkenBird]

On 12/3/2017 at 11:35 AM, JustAndy said:

I've had a similar problem with a Kothe 2-column still at a place I occasionally work. The return pipes from the bottom of each column to the still kettle/boiler don't have a p-trap, valve, or flapper. Inside the still kettle, the return pipes are only about half-way down, meaning they are not submerged in liquid if the liquid level in the still drops below about 275 gallons (in a 500 gallon still). As soon as the liquid level drops below the return pipe, both columns begin to fill with vapor which is problematic if trying to bypass the columns or just use 1 column.    

Have you found a way to combat this problem? When I run my 4 plate for whiskey, the plates function fine but there is obviously an efficiency issue with vapor filling the 16 plate column. When I run all 20 plates there is a constant fight in the 16 plate column. Flooding on the lower 3 plates and #7 force me to manipulate the drain back/bypass valves and the problem persists until late in the run when. I've found that bypassing #7 and #8 help the issue but it does not solve it.

[Southernhighlander]

ThatDrunkenBird,

First try reversing your agitators rotation.  If that does not work, install A P trap in the drain return for each column and run the drain return tube down to within 3" of the bottom of the still pot.   

 

I send my techs all over the US.  Let me know where you are.  If one of my guys is coming by there anytime soon they can do the work for you.

[Silk City Distillers]

Assuming there isn’t a physical issue with the trays (blockage, manufacturing issue), intermittent mid-column flooding is typically due to a slug of subcooled reflux in the column forming a vapor trap.  Usually traces back to sloppy RC flow control, where a spike in cold coolant flow causes a period of very cold reflux.  This liquid is slow to descend, and seemingly appears “stuck”, as the cold temperature of the distillate on the tray causes a disproportionate amount of upflowing vapor to condense.

If shutting down the still for a few minutes, allowing all trays to drain, fixes this, focus on getting better control of your RC coolant.

[Southernhighlander]

If you do not have p traps or a dip tube then that is your problem.  What is happening is you are pushing pressure up through your drain tube which is keeping your lower trays from draining.  When you shut the still down the pressure stops and this allows your trays to drain.  It is very unlikely that this is a dephlegmator flow control issue.  If you can reverse your agitator you might be able to negate the pressure issue by creating suction, thus pulling the column condensate out of the tube, however for that to work the drain tube needs to be positioned a certain way in relation to your agitator, and of course you must have the ability to reverse your agitator.  This information comes from my experience building over 240 stills for distilleries.

[Silk City Distillers]

Another option if the rig is beyond retrofit - Convert to pumped reflux with an explosion proof AODD pump and don’t worry about dip tubes, traps, heights, or differential pressures.   You will, however, need to dial in your pumping speed to match reflux rate, and this may require adjustment throughout the run.

[JustAndy]

22 hours ago, ThatDrunkenBird said:

Have you found a way to combat this problem? When I run my 4 plate for whiskey, the plates function fine but there is obviously an efficiency issue with vapor filling the 16 plate column. When I run all 20 plates there is a constant fight in the 16 plate column. Flooding on the lower 3 plates and #7 force me to manipulate the drain back/bypass valves and the problem persists until late in the run when. I've found that bypassing #7 and #8 help the issue but it does not solve it.

They don't actually use the vodka column for any of the product currently, so I haven't spent much time fooling with it and don't know what sort of issues it has with vapor and plate performance. It has a whiskey helmet which goes into 2- 8 plate columns. The one time I tried to run some wine through both columns, as the plates filled and it started to reflux the vapor turned out to flow up the gin basket return pipe and bypassed the 2nd column entirely (the return line is plumbed into the piping which leads from the top of the 1st column to the bottom of the 2nd). There are some other design issues with the still (like the gin basket was installed backwards so there is no way to open it...) which really astound me.  

[Southernhighlander]

33 minutes ago, Silk City Distillers said:

Another option if the rig is beyond retrofit - Convert to pumped reflux with an explosion proof AODD pump and don’t worry about dip tubes, traps, heights, or differential pressures.   You will, however, need to dial in your pumping speed to match reflux rate, and this may require adjustment throughout the run.

We have a complete kit that will allow you to do just what silk city is referencing.  Email Paul @ distillery-equipment.com

[Southernhighlander]

4 minutes ago, JustAndy said:

They don't actually use the vodka column for any of the product currently, so I haven't spent much time fooling with it and don't know what sort of issues it has with vapor and plate performance. It has a whiskey helmet which goes into 2- 8 plate columns. The one time I tried to run some wine through both columns, as the plates filled and it started to reflux the vapor turned out to flow up the gin basket return pipe and bypassed the 2nd column entirely (the return line is plumbed into the piping which leads from the top of the 1st column to the bottom of the 2nd). There are some other design issues with the still (like the gin basket was installed backwards so there is no way to open it...) which really astound me.  

The biggest problem with Chinese stills is that the Chinese manufacturers do not have a complete understanding of how these more complex systems work.  They just steal the drawings and build them.  More often than not they get it wrong.

[JustAndy]

This is a Kothe, and I imagined they would have the kinks worked out at this point as I've seen the same setup at numerous distilleries. I've used a smaller one at a different facility which has worked flawlessly with no modifications from factory original for 2000+ distillations, so I was surprised at all the issues with this installation.