Flooding in CCVM's Thread

Distillation methods and improvements.

Moderator: Site Moderator

Post Reply
Andrew_90
Rumrunner
Posts: 613
Joined: Sun Aug 30, 2020 9:24 am
Location: Johannesburg, South Africa

Flooding in CCVM's Thread

Post by Andrew_90 »

Not wanting to hijack others threads with flooding posts I thought there may be sufficient interest from others to discuss this topic in a standalone thread. Let me repost my video. This is of the sight glass which is located directly under the take off T. There have been comments on this but perhaps to comment again so that this thread starts from scratch and does not pick up from where the other thread left off.

So my first real run was completed with the the still flooding. https://mavness.co.za/vid/ginstillpercolating.mp4 I accept this "criticism" gladly and will seek to remedy that matter.

My take on the packed column is that it should have vapor rising and distillate descending simultaneously. Ideally one would want this parallel process to take place with neither having any restriction to flow. So for any given molecule of alcohol it will rise up the column to the RC, condense and fall back down the column and the process will be repeated for as many times as it takes the molecule to shed the burden of the wash and to clean up to azeo.

Flooding in the column will provided a "back pressure" which will inhibit the fall of the distillate from the RC through the packing. So any resistance encountered on the way down would not be in the interests of seeking an efficient reflux process. The bubbling head as shown in my video is a restriction but not a blockage. If it was a blockage the sight glass will fill. So the cool distillate will pass through but some may be reheated sufficiently that it immediately rises straight back up without the benefit of dropping and moving through the packing again.

- So then how does one control the "flooding"?
- How do you determine if flooding is happening halfway up the column? After all the coolest part of the column will be the exit to the sight glass. Things are a little more volatile further down the column and could be flooding away.
- It there merit to having the sight glass directly on the boiler or will this not indicate flooding?

So I can see a couple of factors that will require attention;
- Temperature obviously, but more importantly the resolution of the controller. I have been doing test on my controller and have discovered a problem. With a multimeter connected to the 2W 500k potentiometer that controls the kW input there appears to be a very non linear resistance response and or that there simply is not the resolution in the pot to do the job. This results in an inability to dial in the required power. It is almost as if one requires another fine tuning dial. My multimeter is currently in the repair shop so experiments have temporarily been suspended.

The goal is simply to improve the resolution through reducing the range. The controller goes from 0 to 4000W, this is more range than I require so through the addition of resistors I want to reduce the range to 500 to 2200W or an increase in resolution of 2.3X.

Assuming the pot is linear (it is a LIN pot) then the 500k divided by a travel of 270o = a resolution of 1.85 ohms per degree of rotation. Reducing the range will result in a pot of circa 250k which should yield a resolution of circa 0.9 ohms per degree which allows for greatly improved control. So there will be a selector switch to kick in the additional circuit for fine control.

The alternate to this a 3 turn pot which will achieve the same result. This is also a consideration.

- Packing density, too dense and there may not be sufficient path for bidirectional flow.

- Column insulation. This will allow for a more controlled thermal state and should improve all controls.

- The efficiency of the RC. Highly efficient RC's would return more distillate to the column which may or may not be a problem. I noticed a difference in the behaviour of the still when playing with the flow rate of the RC cooling water. I am amazed that the flow that comes down my sight glass.
One too many wasted sunsets, one too many for the road.
Setsumi
Distiller
Posts: 1371
Joined: Tue Sep 07, 2010 10:23 pm
Location: Central South Africa

Re: Flooding in CCVM's Thread

Post by Setsumi »

Although it seems like flooding I think you have a controlled state. Skow69 had a video on here that showed agressive boiling if compared to your video. Unfortuanetly Skow's video looks to be at the beginning of the aquatic state.

It would be interesting to see how large your temprature gradient is in your column. That may indicate a problem.

If you have an amp meter to monitor energy input it may help to understand the vapour speed in your column.

I do not think a sight glass at the bottom is much informative on a packed column BUT in your case it could indicate why you flood. Pack it the same as the column.

Link to Skows video.
https://homedistiller.org/forum/viewtop ... =1&t=54682
My first flute
My press
My twins
My controller
My wife tells me I fell from heaven covered in white. Why did they let me fall?
Andrew_90
Rumrunner
Posts: 613
Joined: Sun Aug 30, 2020 9:24 am
Location: Johannesburg, South Africa

Re: Flooding in CCVM's Thread

Post by Andrew_90 »

I am really confident in my packing and my column insultation, I may yet be proved wrong however.

My digital readout has kW as well as an Amperage and Voltage readouts. I simply battle to dial in small increments in temperature, I want to control to +- 10W but don't think this is possible.

Right now I think it is simply a matter of a lack of experience, one sacrificial run and one product run.
One too many wasted sunsets, one too many for the road.
Setsumi
Distiller
Posts: 1371
Joined: Tue Sep 07, 2010 10:23 pm
Location: Central South Africa

Re: Flooding in CCVM's Thread

Post by Setsumi »

Andrew_90 wrote: Sat Dec 04, 2021 3:32 am I am really confident in my packing and my column insultation, I may yet be proved wrong however.
Insulation minimize ambient influence on packed columns and reduce chaneling on the walls. But inside the packed column there is a natural temprature gradient. Hot on the bottom and cooler on top. This gradient represents the fractioning of constituents.

My reference to this is if you have a small gradient it may indicate flooding and bad fractioning. How large I cannot say at this stage and the gradient would be dynamic... it will change during the run. But a column need it to work.
My first flute
My press
My twins
My controller
My wife tells me I fell from heaven covered in white. Why did they let me fall?
User avatar
bunny
Site Donor
Site Donor
Posts: 398
Joined: Fri Jun 26, 2020 8:28 am

Re: Flooding in CCVM's Thread

Post by bunny »

Hi Andrew_90,
I have a few tidbits of hard learned information. I'll give them to you one or two at a time.

You seem to have missed the discussions on secondary potentiometers. Use your 500K in series with a 50K. Ballpark with the 500K, and dial into the 0.1 A with the 50K.

Perhaps you have a TRMS clamp meter? You MUST use one to get meaningful amp readings to calculate your vapor speed. Your basic RMS clamp meter will not be able to give you useful information on non sinusoidal data.
Andrew_90
Rumrunner
Posts: 613
Joined: Sun Aug 30, 2020 9:24 am
Location: Johannesburg, South Africa

Re: Flooding in CCVM's Thread

Post by Andrew_90 »

Thought I was on the right track with regards to the pots. Thanks.

I do not have a RMS meter. I do have a digital readout with a CT which I believe will be sufficiently accurate. See the below link;

https://www.banggood.com/PZEM-022-Open- ... mds=search

I use the power readout to dial in the required power.
One too many wasted sunsets, one too many for the road.
User avatar
bunny
Site Donor
Site Donor
Posts: 398
Joined: Fri Jun 26, 2020 8:28 am

Re: Flooding in CCVM's Thread

Post by bunny »

You may find this interesting or distressing.https://homedistiller.org/forum/viewtop ... 85&t=84760
User avatar
bluefish_dist
Distiller
Posts: 1502
Joined: Fri Jan 16, 2015 10:13 am
Location: Eastern Ia

Re: Flooding in CCVM's Thread

Post by bluefish_dist »

There does need to be interaction between the falling liquid and raising vapor to help exchange energy. This is the function of the packing. It slows down and mixes the two states to allow for energy transfer. The falling liquid is cooler than it’s boiling point and the vapor is at or slightly above its bp. By creating a temperature gradient with the energy transfer we stack the components by boiling point, with the coldest section at the top and thus the lightest components. Since we run batch vs continuous, what is at the top is slowly changing. Once we remove the lightest component, the next lightest get to the top, until some pretty heavy stuff (aka tails) makes it up.

By flooding the packing I expect we maximize the heat transfer. With SPP being very open it may work better in this condition than ss scrubbies. I found I could not keep scrubbies in a stable flooded state, not saying it can’t be done, just saying I couldn’t do it.
Formerly
Dsp-CO-20051
Andrew_90
Rumrunner
Posts: 613
Joined: Sun Aug 30, 2020 9:24 am
Location: Johannesburg, South Africa

Re: Flooding in CCVM's Thread

Post by Andrew_90 »

Not at all, I am reasonably conversant with ohms law.

So for me the if one has an error in reading it is not actually an issue. If my still works perfectly at a displayed 1450W when in fact is it 1520W that is beong delivered it makes no difference as the error will always be the same. Next time under the same ambient conditions I dial in 1450W and I am good to go.

It only makes a difference when one changes controller and the error is different.

Our mains voltages fluctuate so reading wattage directly from the manel meter works.

I think it is more important to be able to fine tune the power setting through the addition of the 50k pot as ambient conditions will seldom be the same.
One too many wasted sunsets, one too many for the road.
User avatar
bluefish_dist
Distiller
Posts: 1502
Joined: Fri Jan 16, 2015 10:13 am
Location: Eastern Ia

Re: Flooding in CCVM's Thread

Post by bluefish_dist »

As Andrew pointed out, input voltage does fluctuate. I was surprised how much it changes. Enough that if you are on the ragged edge of control it could cause issues. Also power required to maintain the same vapor output changes during the run.
Formerly
Dsp-CO-20051
User avatar
Fletching
Site Donor
Site Donor
Posts: 47
Joined: Fri Dec 03, 2021 6:08 pm
Location: Oklahoma

Re: Flooding in CCVM's Thread

Post by Fletching »

I have experienced the same problems with trying to control in a flooded state using scrubbies. When I switched to SPP, this got a lot better for me. The only “surging” of the flooding I experience now occurs in the very beginning when I haven’t dialed my power down yet.
Here’s to lobster tail and whiskey. Three of my favorite things.

Easy Maceration Boiler https://homedistiller.org/forum/viewtop ... 7#p7691427
Andrew_90
Rumrunner
Posts: 613
Joined: Sun Aug 30, 2020 9:24 am
Location: Johannesburg, South Africa

Re: Flooding in CCVM's Thread

Post by Andrew_90 »

So it would appear as if the type of packing has an effect on flooding?

For the record my column is 1200mm (flange to flange) and starts with 295mm of copper mesh packing at the bottom followed by 875mm of 6mm Raschig Rings. The Raschig Rings will take longer to heat up but I like them as they have more thermal mass which means that they will not gain or lose temperature rapidly, I believe this will result in a more stable column?

The reason for this packing arrangement is that the Raschig Ring suppliers undersupplied (long story) and I was short of rings, I then extended the column by 200mm which exacerbated the matter. The reason for the copper mesh at the bottom, well it is less dense and I though that would allow for the very hot and higher velocity vapor to penetrate the column easier.
One too many wasted sunsets, one too many for the road.
drmiller100
Rumrunner
Posts: 679
Joined: Wed Mar 11, 2009 9:13 pm

Re: Flooding in CCVM's Thread

Post by drmiller100 »

Maybe I missed it but what diameter is your column?

I'd GUESS 2200 watts would be in the 2 inch diameter?
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
Andrew_90
Rumrunner
Posts: 613
Joined: Sun Aug 30, 2020 9:24 am
Location: Johannesburg, South Africa

Re: Flooding in CCVM's Thread

Post by Andrew_90 »

drmiller100 wrote: Sun Dec 05, 2021 7:21 pm Maybe I missed it but what diameter is your column?

I'd GUESS 2200 watts would be in the 2 inch diameter?
2" x 47.25"
One too many wasted sunsets, one too many for the road.
User avatar
shadylane
Master of Distillation
Posts: 10363
Joined: Sat Oct 27, 2007 11:54 pm
Location: Hiding In the Boiler room of the Insane asylum

Re: Flooding in CCVM's Thread

Post by shadylane »

Just a Drunken thought :lol:
As far as a column is concerned, it doesn't know if the still head is CCVM, VM, LM or CM.

Reflux causes flooding.
The faster the takeoff rate, the less reflux available to rain back down and vice versa.
Power, vapor speed, and packing are only part the flooding equation, the percentage of reflux is the other half. :wink:
kimbodious
Distiller
Posts: 1198
Joined: Fri Apr 17, 2015 3:57 pm
Location: Far northern tropics of Australia.

Re: Flooding in CCVM's Thread

Post by kimbodious »

@shady. Agreed. It is super easy to flood a reflux column when it is supposed to be in total reflux.
--
50L Beer keg boiler, 2200W element
Modular 2" Pot Still
opinions are free and everybody has them, experience costs you time
User avatar
shadylane
Master of Distillation
Posts: 10363
Joined: Sat Oct 27, 2007 11:54 pm
Location: Hiding In the Boiler room of the Insane asylum

Re: Flooding in CCVM's Thread

Post by shadylane »

99% reflux is easier to find and hold.
A slow steady drip works great for getting rid of the forshots.
Just my opinion, I've tried running a column in a flooded state and it's not worth the trouble.
The difference is only a fraction of a percent in ABV and flooding seems to make for a less neutral spirit.
Last edited by shadylane on Sun Dec 05, 2021 11:48 pm, edited 1 time in total.
kimbodious
Distiller
Posts: 1198
Joined: Fri Apr 17, 2015 3:57 pm
Location: Far northern tropics of Australia.

Re: Flooding in CCVM's Thread

Post by kimbodious »

You can avoid flooding by reducing the packing but in doing that you reduce the amount of interface where the vapour and condensate can mingle - reduced purification. You can counteract the reduction in purification by increasing the vapour speed BUT by doing so you could be pushing the boiler to the point where everything is smearing.

To return to shady’s comment, you usually need to increase vapour speed when you decrease reflux (eg raise the RC coil).
--
50L Beer keg boiler, 2200W element
Modular 2" Pot Still
opinions are free and everybody has them, experience costs you time
Andrew_90
Rumrunner
Posts: 613
Joined: Sun Aug 30, 2020 9:24 am
Location: Johannesburg, South Africa

Re: Flooding in CCVM's Thread

Post by Andrew_90 »

OK Shady,

I'm with that.

I based my product off take on others with similar column arrangements. I am normally meticulous in my record keeping but I think too much was going on in my first run. Perhaps I was a bit higher in offtake, I remember around 1.2 to 1.5l per hour. So the only way to reduce flooding is to reduce offtake would be to reduce power and therefore flow. Will try at 1l per hour on the next run.

@Kimbodious. Your last sentence has me confused but I think I am understanding. My RC was set below the T during the run, I have noted in prior posts in other threads that the volume of product back down seemed to me to be excessive. This return flow may well added to the flooding simply due to the volume?
One too many wasted sunsets, one too many for the road.
kimbodious
Distiller
Posts: 1198
Joined: Fri Apr 17, 2015 3:57 pm
Location: Far northern tropics of Australia.

Re: Flooding in CCVM's Thread

Post by kimbodious »

@Andrew_90, when you raise the RC coil you get to the point where up to half the vapour is exiting via the offtake. This means there is only about half as much vapour being condensed by the RC coil. This means your risk of flooding is very much reduced. You are then able to increase the vapour speed (through the heating power to the boiler) if you desire a greater rate of product from the PC.
--
50L Beer keg boiler, 2200W element
Modular 2" Pot Still
opinions are free and everybody has them, experience costs you time
User avatar
bluefish_dist
Distiller
Posts: 1502
Joined: Fri Jan 16, 2015 10:13 am
Location: Eastern Ia

Re: Flooding in CCVM's Thread

Post by bluefish_dist »

kimbodious wrote: Mon Dec 06, 2021 4:30 am @Andrew_90, when you raise the RC coil you get to the point where up to half the vapour is exiting via the offtake. This means there is only about half as much vapour being condensed by the RC coil. This means your risk of flooding is very much reduced. You are then able to increase the vapour speed (through the heating power to the boiler) if you desire a greater rate of product from the PC.
Depending on your starting vapor speed you can quickly get the speed too fast and you will drag tails up the column. It’s a balancing act. There is a small range of power, takeoff rate, and vapor speed where more power will help with takeoff rate and purity. Usually you will make a cleaner spirit with less power. When I would get to the end of a run, I could delay tails by lowering power. Once I had dropped power by 30% and could no longer hold a abv, time to shut down.
Formerly
Dsp-CO-20051
Andrew_90
Rumrunner
Posts: 613
Joined: Sun Aug 30, 2020 9:24 am
Location: Johannesburg, South Africa

Re: Flooding in CCVM's Thread

Post by Andrew_90 »

So then there must be a sequence of events. Surely with roughly the same stills people will not have vastly different processes. So lets critique mine if you all don't mind.

So this is what I did.
- RC Coil positioned in full reflux with max cooling flow. No cooling flow to the PC.
- Ensure that there was no vapor leaking out the top of the column and the PC.
- Stabilise column.
- Turn on the PC cooling flow.
- Crank the power up until I was on the verge of / just flooding. As depicted in the video clip.
- Slowly crank the RC up until I was getting 1 drop per second and removed the fore's. My RC is infinitely variable so I have mm control on position.
- Crank up the RC until output was around 1.0l/hour to remove the heads.
- Cranked up the RC until circa 1.2 to 1.5l/hour output was achieved. The RC was not touched after that.
- Kept tweaking the input power to maintain a steady state of what I know believe to be flooding / on the verge of flooding.

Fire away.
One too many wasted sunsets, one too many for the road.
drmiller100
Rumrunner
Posts: 679
Joined: Wed Mar 11, 2009 9:13 pm

Re: Flooding in CCVM's Thread

Post by drmiller100 »

Are the scrubbies squashed flat by the weight of the rings?
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
Andrew_90
Rumrunner
Posts: 613
Joined: Sun Aug 30, 2020 9:24 am
Location: Johannesburg, South Africa

Re: Flooding in CCVM's Thread

Post by Andrew_90 »

I am not sure but the weight of the rings is only 1.7kg and a lot of is is borne by the sides as the rings tend to stick and grip.
One too many wasted sunsets, one too many for the road.
drmiller100
Rumrunner
Posts: 679
Joined: Wed Mar 11, 2009 9:13 pm

Re: Flooding in CCVM's Thread

Post by drmiller100 »

Well,, actually you have a 45 inch tall column saturated with liquid squishing the scrubbers

I really doubt the rings are hanging onto the walls very hard.
Now I know how you claim azeo so easy, it's based on a meat thermometer. :lol:
kimbodious
Distiller
Posts: 1198
Joined: Fri Apr 17, 2015 3:57 pm
Location: Far northern tropics of Australia.

Re: Flooding in CCVM's Thread

Post by kimbodious »

@Andrew_90, your sequence is similar to mine. I heat up slowly using the power setting I use for hearts. I keep the system in total reflux until I see/ hear the signs that it is stabilised, takes 45 mins - 1 hour. I don’t push the system that it is on the verge of flooding, like I used to. I find that the purity of the product decreases fairly noticeably if I am collecting at or above 1.5 litres per hour. My condensers are plumbed in series.
--
50L Beer keg boiler, 2200W element
Modular 2" Pot Still
opinions are free and everybody has them, experience costs you time
Post Reply