Revamped still

[deeferdog]

Just recently I decided on a major revamp to fix all the things that made running the still a pain, such as leaking water hoses, no heater control, knocking over the distillate collection bottle, (serious pain!) and all the other ratty bits that creep into new projects.The column I made about four years ago and it has always delivered good results.
The major problem has been the readiness of the column to flood and although now I can see the signs and take action, especially now that I have heater control, I just wonder where I have gone wrong in the column design. The scrubbers are SS and packed in tightly but I can breathe through it, they end well below the take off plate. The condenser seems to handle the load well, I suspect that it is oversized. I adjust for a water flow rate of around 1 litre a minute and this keeps the water out temp around 40 C.
After the column has stabilized and I have gotten rid of the heads I run a take off rate around three drips per second, this gives me a purity of 88 to 90 and I'm happy with this. A 20 litre TPW gives me around 2.5 litres.
So everything should be fine except for this flooding, which seems to occur at random, it probably doesn't but I don't have the experience to pick the build up. The first thing I know is the gurgle from the column. What I generally do in these situations is open the take off valve and bleed the column and, now that I have heater control, knock it back to under a kilowatt.
I hate doing this because it upsets the column and it takes time for stability to be re established.
I have two questions. What are the things in column design that encourage flooding? Secondly, is it possible to build in an alert system to warn me that the column is heading towards the flooding stage well before the dreaded "gurgle"? I suspect that the pressure in the boiler will increase due to the liquid plug starting to block the top of the column. I realise that the pressure rise would be small, but if I connected a U tube style manometer would that give advance warning? (Third question, I know).
Thanks to all who are interested enough to read this. Regards,

deeferdog

[skow69]

Can you explain your still, please?

[Hound Dog]

Can you explain your still, please?

Yea, what the heck is all that?

As for flood detection, a site glass at the top of your packing is the easiest way to maintain things. You can see when you are getting fluid build up there and make adjustments to keep just a little bit of flood right at the top and it will purr right along.

[rad14701]

I am also very curious about this still design... What, exactly, is it made out of is the first thing that comes to mind... And what are all the contraptions all over it...??? The column appears to a bit short and that will contribute to the lower %ABV of your spirits... Make it a bit taller and use marbles instead of SS scrubbers and you should be able to run faster, at higher %ABV, without flooding...

[okie]

I'm not sure I know what I'm looking at. Is this for vodka or clear liquor?

[deeferdog]

Thanks for all the replies. I have posted a few pics which will help explain. The still design is fairly basic, Boka with slant collection. The plates are SS scrubbers. Three temps are monitored, under the collection plate, the boiler and the exit water. The 2Kw element is controlled with a 4Kw SCR and is monitored with a power consumption meter. The whole set up is on wheels. A stabilizer bar runs up the back and attaches to the top of the column for the purpose of rigidity. The collection jar is in a PVC holder that clips to the column. This allows it to be swung out of the way of the collection spout. Water flow is monitored through a flow meter. I put a bit of effort into this in an attempt to overcome all the problems that plagued me when I used it in it's previous form which was primitive to say the least. This new design suits me, I just push it to the tap, connect the hoses and away we go. I now know a lot more about what's going on when the still is in operation and I like to know why things are happening. If I put a sight glass in, that will tell me when the flooding commences but I will be no wiser as to why. If the packing is too tight, then how tight should it be? Is there any way measure packing tightness? I could go on and on as this is an absorbing hobby for me and I have the time to put into it. I look forward to any suggestions and would like th thank those who have already assisted. Regards,

Deeferdog

[thecroweater]

Seems to look fine to me, as others have said a sight glass will give you a visual aid for the flooding issue, not needed but it is another tool for the box. I would guess you are simply running it a bit hot, drop the energy a bit and it shouldn't effect your already regulated output rate and with no flooding and excessive canalsing your ABV will improve out of sight. Neat still with some cool innovations

[skow69]

What causes flooding is too much heat input. I'm surprised that you need to turn it down below 1 kw. Is that 2 inch? You should be able to find a stable input level well above that, and end up maxed out at 2 kw by the end of a run. Maybe you are overshooting and yoyoing up and down. A sight glass would help. 3 drips per second is pretty slow. You will be able to feed it more power if you increase the takeoff rate.

I am not aware of any standard elements of still design that are known to increase the propensity to flood. You should experiment with packing to prove that to yourself. I have used scrubbies, lava rock, and SPP, and found no substantial difference. I also tend to pack my column very tight, to where it is difficult to blow through. I have seen that cause excess pressure in the boiler, but little to no difference in flood level.

EDIT: Maybe you run it that slow to keep the ABV up. If that is the case, then the fix is a taller column.

[Hound Dog]

I see now. Pretty nice set up really. How do you keep the condensate liquor running off the collection plate from running on your thermometer? It is typically placed under the top plate so that it can act as a shield for falling liquid.

Like Croweater said, the sight glass I suggest is just a handy tool. The tightness of your packing depends greatly on how hard you run your rig. I would agree with Rad, try marbles. They only pack as tight or loose as they are. You get the same results each time. Same with lava rocks, once you find what size works best for you (by trial and error mostly) you can stick with it and have the same results each time. Mesh or scrubbers can be different each time depending on how you put them in. By the looks of it you are set up for repeat performance. Good monitoring will get you that.

I missed it, how tall is the packed section?

[rgreen2002]

deeferdog I ran a 2 inch Boka for a while and after getting up to temp usually never need any more than about 1500kw to run at about the same rate you suggest (3-4 drops/second). Only had one flood event and that was a molasses that got stuck in the packing and caused a heat surge (I believe)... what a mess!

I think skow is right with too much heat...try a little lower. One of the biggest reasons I switched to the flute was speed. My Boka could produce aezo every time, but the runs were hours and hours. No regrets though!

My girl

Her eye...

And while I do agree that it won't help you solve the flooding issues it really was a window into how she worked.

BAM!

[deeferdog]

Thanks to all. I have just finished an experiment to determine the pressure build up in the boiler vs the power input. I made a rudimentary manometer and connected that to the pot through a small cock. I put 3 litres of water in the boiler and ran it flat out at 2 Kw. The water flow through the condenser was 1 litre/min with outlet temp of 42 C. The pressure in the pot rose to approx. 0.07 psi. When I reduced to power to 1 Kw the pressure fell to 0.03 psi approx. The picture quality is not great and the experiment and the figures are a bit rubbery but it is raining heavy enough to frighten Noah at the moment and I am having difficulty in seeing the scales, so I will give it away for today. Tomorrow, if we haven't all been washed away here, I will do a full run with a TPW that is about ready and see if I can get a good set of numbers. If this all works, and I sure hope it does, then using a manometer to monitor boiler pressure would be a good way to indicate a potential flooding problem, IF, and it's a big if at the moment, excessive boiler pressure causes liquid build up in the upper part of the column. My column is 600mm (2 foot) to the collection point and is completely open at the top. The purity I get is pretty good, see pic of my last run, however it is never that at the end, more like 88 - 90. I always finish the hearts run at 80 C so am I going too far or is this a smearing problem caused by the flooding? Love this hobby! Look forward to your thoughts. Regards,

Deeferdog

[Mikey-moo]

That's some first rate McGuyvering you got going on. Love the use of the steel rule.

Have you tried using marbles as packing. I'm half way through a thread all about them. Looks promising so far.

[thecroweater]

That's some first rate McGuyvering you got going on. Love the use of the steel rule.

Have you tried using marbles as packing. I'm half way through a thread all about them. Looks promising so far.

Not sure unmodified marbles would be "better" per say than scrubbies , always found structured copper outstanding and scrubbers just about as good

[kimbodious]

Hey deefer,
Your system is really well insulated. I am tipping your heating is equally really efficient and your problem is simply too much vapour pressure because your wash? low wines? is in a hubbla bubbla state of boil. I wonder how much ambient temperatures affect heating efficiency? Usually up here 1600 kms further North in Cowboys country we cop all the rain, you are welcome to some of ours at the moment

[Hound Dog]

If you added two more feet into your column, you could go faster than drip speed and maintain equalibrium easier. You are doing a heck of a job now with a 2 foot section.

[rad14701]

That's some first rate McGuyvering you got going on. Love the use of the steel rule.

Have you tried using marbles as packing. I'm half way through a thread all about them. Looks promising so far.

Not sure unmodified marbles would be "better" per say than scrubbies , always found structured copper outstanding and scrubbers just about as good

Marbles allow for the addition of more heat which equates to more vapor which results in more reflux which allows faster take off rates at azeotrope without flooding or breaking equilibrium... My results have been to be able to go from 4 - 5 drips per second to 1oz per minute take off rate at 95% with absolutely no flooding...

[thecroweater]

Yes no doubt but I can get similar results from structured packing