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Running a vodka column with a Danfoss valve


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We had our pot/column on one. Bulb read water temp inside the dephleg. We tried to hold 20C there. The inlet of the dephleg was on bottom with constant pressure. The outlet of the dephleg was on top and that is where the Danfoss was. Hope this helps!

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Which Danfoss?  The integral unit (FJVA) or the remote bulb (AVTA)?  The integral unit has a small orifice bypass to keep water flowing to the internal temp sensor, the remote bulb has no bypass.  That remote bulb becomes problematic if you try to install it in the dephleg output plumbing (especially without a bypass).  The integral can be problematic when your dephleg is running cold water at high flow rates - the lag time will often cause cycling - wavering temps).

Both can work well, assuming you take into account some of these factors.  In both cases, tempering your input water through your PC to reduce the potential for cycling, can help smooth out temps - however this requires that your product condenser is not undersized, nor is your dephlegmator.

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@Silk City Distillers @Stumpy's it's an integral.  

We run the cooling water into the condenser, out via the Danfoss sensor assembly, then into the second dephleg and finally into the first dephleg and out to the return.

We run a recirculated cooling water system using two 1800 gallon wine tanks cooled to 55F. We switch tanks once we hit 65F. The system operates at 75 psi.  

I can get both columns balanced (equally loaded plates) but no output.  I try to increase heat input or raise the dephleg temp the top plate floods and overflows. 

The water pressure maybe too high and needs to be throttled back. 

Another ideas?

Thanks

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Yours looks like one of our Danfoss set ups.  Try increasing the temp setting on the danfos and allow a little bypas at the danfoss valve.  If that doesn't work increase the temp setting more.  Also you should try bypassing the dephlegmator on column 1 completely.

 

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58 minutes ago, Southernhighlander said:

You need a reverse acting Danfoss valve and here is how it should be set up.

 

Danfoss-Valve-Placement - Rev.03292022-Single Column.jpg

There is not enough room between the condenser and the column to install as illustrated - that is why it's reverse from illustrated but the flow is maintained as diagrammed.  This still flows from right to left, too.

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56 minutes ago, Southernhighlander said:

Yours looks like one of our Danfoss set ups.  Try increasing the temp setting on the danfos and allow a little bypas at the danfoss valve.  If that doesn't work increase the temp setting more.  Also you should try bypassing the dephlegmator on column 1 completely.

 

It is your still. 

As I stated in my reply to @Silk City Distillers & @Stumpy's I can get the columns balanced with no output but I increase the temp on the Danfoss or up the boiler temp, the top plate floods and overflows.  

Extremely frustrating - I think we have tried every combination to affect the output with no result. (expect knocking down the cooling water flow).  

Getting desperate because we have vodka orders we need to fulfill ASAP. 

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29 minutes ago, Silk City Distillers said:

That's an interesting approach - you are basically controlling the input temperature to the dephlegmator, but not the flow rate.

 

The reverse acting Danfoss valve controls the flow rate.  It does so proportionally to maintain the coolant temp going into the dephlegmator.  If you are running vodka and the danfoss valve is set to 120F then if the temp of the coolant coming out of the final condenser increases above 120F the thermostatic valve's orifice opens more to increase the flow rate which brings the temp down to 120.  Also, unlike with on off flow control valves, the Danfoss acting in a proportional manner gives a steady output of distillate.

 

 

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Golden Beaver,  You should try bypassing the Danfoss valve to completely control the coolant flow manually to see if the still will function correctly manually.  If you cannot get correct functionality manually something is wrong other than the valve.  If you get correct functionality manually then there is something wrong with the valve.  

Also if you purchased the valve from us it will be a reverse acting valve.  If you purchased it yourself and did not purchase a reverse acting valve it will never work.  Did you just buy your column from us or your complete still including the still pot?

 

 

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1 hour ago, Southernhighlander said:

Golden Beaver,  You should try bypassing the Danfoss valve to completely control the coolant flow manually to see if the still will function correctly manually.  If you cannot get correct functionality manually something is wrong other than the valve.  If you get correct functionality manually then there is something wrong with the valve.  

Also if you purchased the valve from us it will be a reverse acting valve.  If you purchased it yourself and did not purchase a reverse acting valve it will never work.  Did you just buy your column from us or your complete still including the still pot?

 

 

We just bought the whole setup including the Danfoss valve from you last month...the valve is working correctly as far as we can tell (it's engaging and opening).

The issue I see is that the Danfoss is useless if the condenser is not cooling distillate. If we can't get output without flooding the top plate, there is no distillate to cool and condense so the valve operation is mute.

Am a pot still guy, not a column guy. I'm sure we're missing something but it's just not apparent to us.

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4 hours ago, Golden Beaver Distillery said:

The issue I see is that the Danfoss is useless if the condenser is not cooling distillate. If we can't get output without flooding the top plate, there is no distillate to cool and condense so the valve operation is mute.

If im understanding what your saying correctly. In a sense yes it is useless. If hot vapor isn't getting to the top of the final condenser and water isn't running past the temp sensor yes the valve will remain closed.  Or at least very constricted.  

  This is why you run your set up with the bypass valve opened up first so that water is flowing through the system and it allows you to pack the column   Then you slowly dial that manual valve down as you do this it will start to allow vapor to the top of the final condonsor and the water going out will start to affect the temp sensor now because its hot and eventualy you can almost turn off the bypass valve completely   and the danfoss will do its job maintaining the temp 

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Yep that's the right valve.  We've been having our customers plumb them like this for some time with good results.   

 

I think you should run her manually.  Go ahead and bypass both plate columns with your vaper and also bypass both dephlegmators so that no coolant is going through them and see if you get any output and then we will move on from there to running one column.  It might be more expedient if we do this over the phone.  Call me when you set things to run  at 417-778-6908 and we'll get her lined out.

Thanks.

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4 minutes ago, whiskeytango said:

If im understanding what your saying correctly. In a sense yes it is useless. If hot vapor isn't getting to the top of the final condenser and water isn't running past the temp sensor yes the valve will remain closed.  Or at least very constricted.  

  This is why you run your set up with the bypass valve opened up first so that water is flowing through the system and it allows you to pack the column   Then you slowly dial that manual valve down as you do this it will start to allow vapor to the top of the final condonsor and the water going out will start to affect the temp sensor now because its hot and eventualy you can almost turn off the bypass valve completely   and the danfoss will do its job maintaining the temp 

Thanks Whiskey Tango.   

Golden Beaver, I'm sorry I thought that you had already loaded the plates by bypassing the Danfoss valve.  It's been a long day for me. 

If you run as Whiskey Tango describes you should start getting some output. 

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I might have done something wrong, but I never liked the operation of the danfoss and when we ran one it always seemed to be open a little too much or too little too closed.

We switched back to metered needle valves and it works very well for us.  We have them on our single column still and two column vodka still.  For the most part we turn the still on, set each meter to whatever flow rate we know works best, and have to make very few adjustments between the beginning and end of the run.  Our cooling is a constant temperature, so our setup might not be ideal if you have coolant temperature creep.

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19 hours ago, Golden Beaver Distillery said:

Extremely frustrating - I think we have tried every combination to affect the output with no result. (expect knocking down the cooling water flow).  

 

 

13 hours ago, Southernhighlander said:

Thanks Whiskey Tango.   

Golden Beaver, I'm sorry I thought that you had already loaded the plates by bypassing the Danfoss valve.  It's been a long day for me. 

If you run as Whiskey Tango describes you should start getting some output. 

As I stated in an earlier post we've started with all three bypasses engaged.  We will try again today but also reducing the incoming water flow pressure per @Silk City Distillers observation.

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I'm not Paul (don't know his rigs), but I'd be glad to hop on a Facetime/Video call with you and walk through real time.

Based on what I'm seeing, you should be able to get this to work.

You should be starting with valves full open through Dephleg 1 and 2, and only enough flow through the PC Bypass to be able to just barely hit 100% reflux to load the plates, which will be a pretty small amount of overall flow.  It's a ball valve, so tiny adjustments will make huge differences in flow rate.  Input coolant at 55f is plenty cold enough to easily generate full reflux.

Too high of a flow rate through the Dephlegmators will over cool the reflux, and result in top plate flooding that will be challenging to settle down without turning off heat to the kettle and allowing the pressure to reduce so the plates can drain down.  Top plate flooding, or flooding on some seemingly random plate in the column, is almost **ALWAYS** due to subcooled reflux creating a kind of block in the column, as the liquid is cold enough to condense the vapor trying to pass through it.  Where the flooding will sit in the column will tend to be based on the backpressure generated by the kettle vapor generation.  Quickly turning off heat to the kettle will drop the vapor pressure and allow the reflux to drain down to subsequent plates.  Usually a quick on and off is all it takes to force the column to restack.

You said something about 75psi on the water feed, having the PC valve full open is going to be way too much flow.

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48 minutes ago, Silk City Distillers said:

"I'm not Paul (don't know his rigs), but I'd be glad to hop on a Facetime/Video call with you and walk through real time.

Based on what I'm seeing, you should be able to get this to work.

You should be starting with valves full open through Dephleg 1 and 2, and only enough flow through the PC Bypass to be able to just barely hit 100% reflux to load the plates, which will be a pretty small amount of overall flow.  It's a ball valve, so tiny adjustments will make huge differences in flow rate.  Input coolant at 55f is plenty cold enough to easily generate full reflux.

Too high of a flow rate through the Dephlegmators will over cool the reflux, and result in top plate flooding that will be challenging to settle down without turning off heat to the kettle and allowing the pressure to reduce so the plates can drain down.  Top plate flooding, or flooding on some seemingly random plate in the column, is almost **ALWAYS** due to subcooled reflux creating a kind of block in the column, as the liquid is cold enough to condense the vapor trying to pass through it.  Where the flooding will sit in the column will tend to be based on the backpressure generated by the kettle vapor generation.  Quickly turning off heat to the kettle will drop the vapor pressure and allow the reflux to drain down to subsequent plates.  Usually a quick on and off is all it takes to force the column to restack.

You said something about 75psi on the water feed, having the PC valve full open is going to be way too much flow."

 

 

Thank you Silk.  This is a great explanation of what needs to be done.

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Golden Beaver,

I believe that Silk and Whiskey Tango's advice is spot on, especially Silks advice concerning your high pressure and backing off the coolant flow.  With that kind of pressure and the size of your lines you have far more flow than you need in this situation.   I rarely run stills anymore so the insight of people that run stills everyday can be really helpful in a situation like this.

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Another thing to think about is the size of the wash and the size of the column.  If your wash volume is smaller and your low abv you might have a hard time just packing the column due to not enough alcohol in the wash to fill it causing a very slow / takeoff.  

 

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2 hours ago, whiskeytango said:

Another thing to think about is the size of the wash and the size of the column.  If your wash volume is smaller and your low abv you might have a hard time just packing the column due to not enough alcohol in the wash to fill it causing a very slow / takeoff.  

 

@whiskeytangoThis is double distilled distillate @ 100 proof / 100 gallons in 150 gallon pot.   Should be no issue.

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