Plate column Surging

Vapor, Liquid or Cooling Management. Flutes, plates, etc.

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frunobulax
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Plate column Surging

Post by frunobulax »

I have a 4'' Perf plate column that I've run 5xs. The first two sacrificial runs with sugar went ok. The last 3 with all grain surged. The hydrometer in the parrot bobbed and it spit out of
the vent hole. (It would only spit if collecting, not in full reflux) The surge was not only in the parrot, but the bubbles on the plates rose and lowered as well and seemed to coincide with the parrot bob/spit. At full reflux, if I put my hand next to the parrot vent, I could feel air intermittently blowing out and even cause a slight bob of hydrometer.. I tried every variation of heating/cooling I could think of. I thought it may be super cooling in the deflag but that would only huff when collecting?
I'm heating with a 12" Natural gas banjo burner which is very steady and it's in my garage, so there isn't any breezes etc.
There's two other things that I can think of that may cause this. the 4x2 reducer not letting vapor up evenly, (but I've never heard of anyone having a problem)
or, the boiler is surging and I need something for boiler chips, which I'm thinking it may be. Even when making beer I have a 2 gallon per hour boil off rate, but in all my reading never heard of anyone having this problem in a column.
Any suggestions will be greatly appreciated!
Thanks
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Re: Plate column Surging

Post by bearriver »

Can you post a picture of the rig?
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Re: Plate column Surging

Post by frunobulax »

I forgot, It's on a 15.5 keg. And the water supply is city water, the hose bib it's connected to is supplied before the house is.
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Re: Plate column Surging

Post by bearriver »

I don't see a vent on the parrot. If there is not one, then that is source of your problem. :thumbup:

Its a common oversight, that I have made myself...
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Re: Plate column Surging

Post by frunobulax »

There is one.
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Re: Plate column Surging

Post by LWTCS »

Talk about the plates more.
Where is the liquid level at on each plate during 100% reflux mode?
Where is the liquid level at on each plate when collecting?
Is the liquid level reasonably equal during each?
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Re: Plate column Surging

Post by Sungy »

I think this may be caused by city water temp at 52f. You are running full flow threw your product condenser and regulating flow threw dephleg with a bypass valve. I think rapid vapor condensing is the cause. I would split the cooling water to feed both condensers separately with 2 valves. Adjust product condenser flow so that the cooling water exiting has gained some temp and your spirit is cool. The setup you have now works well with recirculating water from a barrel as it will be warmer than city water.
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Re: Plate column Surging

Post by LWTCS »

Sungy is correct in that there is a temp split / relatioship between discharge water temp and vapor head temp.
That looks like a big dephlegmator. Try less water but don't starve your product condenser in the process.
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Re: Plate column Surging

Post by LWTCS »

Also how big are the tubes in the dephlegmator?
They need to be sized to allow for two way traffic flow.
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Re: Plate column Surging

Post by googe »

sometimes I get surging on the plates at full reflux if running to fast, running at a nice speed it was fine, never had it at the parrot. What speed are you running it at?.
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Re: Plate column Surging

Post by frunobulax »

Thanks, The deflag is not a big as it looks The cooling section is only 4.5" with 7 -1/2'' tubes.
Yes, The water is run through the Product condenser to a T to waste, then to the Deflag which also has a needle valve on the output side it to control it separately. I thought having preheated water going to the deflag would keep it more stable. Sungy,are you talking about vapor collapse in the deflag itself? I thought that also, but if I'm not condensing product, then wouldn't that water be at a stable temp? I've tried running it slow, with just enough heat to keep the plates full and hot where the bubbles are way up on the site glasses, and it surges regardless.
Thanks for the input guys, I really appreciate it. I'm anxious to get it square and not aggravate me!
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Re: Plate column Surging

Post by Sungy »

If the surging does not happen when in full reflux I think your dephleg is fine. From my experience with surging it was in the product condenser. I tried running city water at 52f and my float bobbed up and down in my parrot. When I slowed down the water flow through my product condenser to a trickle and allowed it to gain 20f in temperature the float bobbing stopped.
Just my opinion...
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Re: Plate column Surging

Post by frunobulax »

It surges in full reflux, That's when I can feel the air being pushed out the vent for the parrot. The bubbles on the plate will rise and fall rise and fall, Not super extreme but
enough to know it's doing it.
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Re: Plate column Surging

Post by Sungy »

Ok my bad...thought the issue was in the PC.

Ok so now that Ive been brought back to reallity...

Sugar washes dont foam much in your boiler. That being said AG and molasses spirits do foam...A lot....

My guess is the boiler charge is to large and there isnt enough head space for the foam created. This will cause foam to fill the column below your first plate.

What is the boiler charge your using? I find 12 gallons fine for sugar heads but 11 works best for my rum and whiskey..
For very foamy washes I add 3 oz vegetable oil to the boiler (15Gallon) to break down the surface tension of the bubbles.
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Re: Plate column Surging

Post by frunobulax »

The charges were only 10.5 gallons in a 15.5 gallon keg. I tried for 12 but that damn yeast/trub...............
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Re: Plate column Surging

Post by LWTCS »

If you were running bubble caps I'd tell you to incrementally turn down your heat and turn down your dephlegmator water flow until you get the system to behave.

Not sure how well your perf plates would cope with that recommendation though?
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Re: Plate column Surging

Post by googe »

I'd agree it's to do with your wash, and foaming/surging/huffing, if it is, it should settle down after a while though!. My surging settles after I've turned down the heat or taken some product, I have caps, so can't say if sieves do the same?. bubbles way up the glass to me would suggest your running to hard for the wash, with my runs it is anyway. I'd do some fiddling and lower the heat till your plates are right on the verge of collapsing and see if it surges still.
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Re: Plate column Surging

Post by rager »

not to hijack but I just want to make sure I understand what im seeing.

cool water into PC "shotgun" im assuming.

out to the inlet of the dephleg ,

then out the top of dephleg

?

Im trying to get a grasp on this. cooling , not to mention the separate valves for control .

great looking rig btw :clap:

from a pot still it sounds like huffing. and I agree that maybe a little larger vent could help and cooling water control . but only take that with a finger and a cube. im a newb when it comes to this stuff but im trying to learn

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Re: Plate column Surging

Post by frunobulax »

There is only 1-5/16" Vent hole. It did seem restricted when I blew into it. I wish I paid more attention to it when the drain valve was open
while collecting foreshots. I will definitely drill a couple more.
Googe, The only reason I ran it that hard was to try all settings, I actually turned it down low enough to have it collapse too. If nothing else I'm learning all of the variables in running this thing! I also would think foaming in the boiler would subside, I wish I had a site glass in the boiler to see.
Rager, you have the water routing correct. That valve between the water in to the deflag and water out is a one way valve that lets the water from the PC not being used by the deflag to go out (the deflag has a one way valve on the exit too) I thought that was pretty clever, but if I knew anything,
I would not be posting here..lol.
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Re: Plate column Surging

Post by still_stirrin »

I'm not a "fluteman", but I'm wondering if it is a heat input overload too. Your deflag is quite adequately sized for your flute's throughput. And your product condenser seems to be very well matched as well. But your boiler output is only 2" into a 4" flute. That would imply a fast vapor velocity in the orifice to load the plates properly.

As you originally suggested in your opening comments, you may be right on the threshold of your boiler's output. If you turn the heat down on your banjo a little more, does that cause the plates to collapse? You could be seeing the effects of the column refluxing through the "choked" vapor path.

Again, I'm not a flute operator but I am a mechanical design engineer with production vessel design experience.

ss

edit - remember 4" is 4 times as much flow area as 2".
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Re: Plate column Surging

Post by still_stirrin »

Hey, I'm thinking out loud here, but do you flute operators think that a short 4" extension between the 4x2 reducer and the 1st plate would help to stabilize the vapor flow? Or even possibly insulating the 4x2 reducer?

Again, it feells to me like the refluxing liquid off the bottom plate is causing the surging through the 2" Triclover joint.

Experts?

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Re: Plate column Surging

Post by frunobulax »

I actually have a 4" ferrule ready to be welded on the keg, but haven't gotten around to it. I see alot of guys using reducers without issues so
I'm GUESSING that the pressure equalizes once it's in the column. My Banjo burner is very adjustable. I can bring it to a simmer or a raging boil.
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Re: Plate column Surging

Post by still_stirrin »

frunobulax wrote:I actually have a 4" ferrule ready to be welded on the keg, but haven't gotten around to it. I see alot of guys using reducers without issues so
I'm GUESSING that the pressure equalizes once it's in the column. My Banjo burner is very adjustable. I can bring it to a simmer or a raging boil.
But pressure imballance is the surging/pulsing you're experiencing.

Again, I suspect that you're seeing the liquid causing vapor collapse in the hi-velocity area through the 2". The vpaor needs to stay in the vapor phase until the flow gets up to the plates, where you want the state to change. The velocity change, and corresponding static pressure change, as you go from 2" to 4" can cause the vapor to fall below its boiling point and condense before you actually get to the plates.

I do believe that your 4" ferrule would solve your instability problems and even allow greater throughput.

Also, I'd bet that increasing the 4" section between your reducer and your 1st plate would help with stability.

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Re: Plate column Surging

Post by googe »

Sounds like a coup@e of probs you have frunobulax, the surging can't be to do with the parrot vent size, so you need to trouble shoot that and then trouble shoot the parrot vent, I would imagine. Id like to ask some questions just to get things clear as I've always wondered myself about this problem, I remember talking to someone about it ages ago and they said there's surged to, on all different washes, but had no explanation for it.
It only does it with ag?.
Have you done a sugar wash again since the ag?
It surges when collecting and full reflux?.
Is the surging a fast surge or slow?.
Did the hydrometer miss behave when doing the first sugar washes?.

I've tried spacers below the first plate, from 100mm to 300mm and did not notice any change large enough to warrant it.
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Re: Plate column Surging

Post by frunobulax »

Googe, It seems to be with ag. The first sacrificial run went ok, then I ran straight corn and thats when I saw it surging, so I still had all of the stuff from the sacrificial run plus some feints I had laying around and ran that. It ran fine. Then the next two runs, one all corn and one all barley it surged. It surges full reflux, low reflux, High heat, low heat, (just not as bad low heat). On high heat the air from the surge can bob the Hydro. in the parrot,(no dissilate), so I did drill 3 more holes in it.
I made a bourbon wash Sunday that should be ready for this Sunday so I can try any changes
then (Except the reducer, I won't have time to have it welded). If I find the time, there may be enough crap laying around here to run just to load the plates and see what happens.
Thanks.
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Re: Plate column Surging

Post by SoMo »

Have you tried adding the bit of veg or olive oil?
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Re: Plate column Surging

Post by frunobulax »

I do use 5 star defoamer to prevent puking, but I believe boil surge is something different altogether.
I'm thinking that it takes X amount of heat to keep the column stable and that is enough heat to cause a surge boil....?
I notice when I make beer (all grain boils) its not always a steady boil, like water ( or a sugar wash perhaps?)
This is just my guess and I will try any other suggestions.
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Re: Plate column Surging

Post by frunobulax »

I ran this yesterday with the crap I had around, a charge of 8 gallons at 9% It ran perfect. The all grain Bourbon wash will be ready to run by the weekend, so I'll put something in
the bottom of the boiler and see what happens then.
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Re: Plate column Surging

Post by emptyglass »

frunobulax wrote:I notice when I make beer (all grain boils) its not always a steady boil, like water ( or a sugar wash perhaps?).
I think you might have found the cause....
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Re: Plate column Surging

Post by APR »

frunobulax wrote:I ran this yesterday with the crap I had around, a charge of 8 gallons at 9% It ran perfect. The all grain Bourbon wash will be ready to run by the weekend, so I'll put something in
the bottom of the boiler and see what happens then.
If you still have the surging, what I would do is remove everything past the deflag and run the still on full reflux and see if you can then see fluid surging on the plates. This would at least isolate past the deflag as the possible cause.

Is there a steady flow of fluid from each downcomer while the surging is occurring, or is the downcomer fluid flow erratic and in sequence with the surging??
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