Enhancing Semi Flooding Condition with SPP

sergiolis

I would like to ask how we could enhance semi-flooding in a packed column with SPP.
By increasing the height of the column and the amount of SPP we are increasing liquid retention.
It may mean that the pressure buildup will also increase a little and consequently we will need less power to achieve the semi-flooding condition.
I am a bit power limited but I would like to know if there are other ways to reach this condition.
I am also not convinced if a bigger charge in the boiler could enhance semi-flooding too.....
All these factors working with SPP are a bit confusing to me.
Have a nice day!!

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StillerBoy

As an advocate of running a reflux column in the semi flooded state (SFS) with experience in both SPP and lava rocks, but I would need more info before providing further info on it..
What is the column size and length and style of reflux column setup are you asking questions on..  what is the power availability gas, 120V or 240V or something in between as you're in Spain..  and do you have a good source of water availability and flow...
And a large boiler charge has no bearing on the running in SFS, cause it is manage by the amount power used.. also best done using a sight glass at the top..
Mars" I know quite certainly that I myself have no special talent. Curiosity, Obsession and dogged endurance, combined with self-criticism, have brought me to my knowledge and understanding "
– Albert Einstein

sergiolis

Hi StillerBoy,
I'm trying to update my system from a 3.5" column (85mm ID) to a 4" column (103mm ID)
I work with LM Bokabob, both of them. My limiting power is 13Kw (240v).
The 3.5" column packed with 130cm with SPP is working nicely with 9Kw and I can see bubbles (liquid boiling or SFS) near the top of SPP through a sight glass at this power.
But I cannot get it with 4". Same SPP (4.2x4.2x0.24mm), same boiler, same boiler charge, a bit less packed height of 120cm. I suppose many factors are involved. I shot 12 or 13 Kw testing the column but couldn't see a SFS. Probably I need more power.
But as I know there is a formula which states that power is proportional to the square diameter of the column. In my case it's not true.
From 2" to 3" I needed 1.55 times more power (from 2.6Kw to 4 Kw). It was reasonable.
From 3" (72mm ID) to 3.5" (85mm ID) I needed 2.25 times more power, in other numbers, from 4kw to 9kw. This disproportion makes me think of some aspects beyond me.  

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Should be much more factors because the proportional law doesn't exist to me.
Just wondering if there are more ways to enhance SFS if you don't have enough power or you want to save some electricity.
I would love to see my 4" pipe bubbling...... Thanks for your quick answer  

StillerBoy

I would forget about the formula, as it's just good for info, as you have already experience..
From what you have stated, and from what you also have stated about using your full power available, you are still short of the necessary power required to get to the SFS..  
There was a post a few days ago on something similar about not enough power to make the column work properly, in that case it was from 4" to 8"..  power is the magical answer unfortunately..
As to doing something to get it to SFS, one could try some highly compressed ss scrubbies at the base for about 4 - 6", and see if the restriction created will cause it to get there..
I'm not a fan of 4' column, as I find that the 2" is a very good all around setup, for a few reason, but the main one I don't like to babysit for more than 6 hrs..
Mars" I know quite certainly that I myself have no special talent. Curiosity, Obsession and dogged endurance, combined with self-criticism, have brought me to my knowledge and understanding "
– Albert Einstein

Salt-Must-Flow

sergiolis, what SPP do you use? Did you buy that Doctor Gradus SPP? If so, which size? Do you know what the specs are?Last edited by Salt Must Flow on Wed Sep 21, 2022 6:33 am, edited 1 time in total.

TwoSheds

I have limited (and moderately frustrated) experience running a semi-flooded column, but given your set up and if you're already topped out on the power input the best thing might be to try to send more of that power up the column.
So if you haven't already, insulate your boiler, including the bottom, and your column where you don't have sightglass. That will at least minimize the energy loss to the atmosphere and put as much power as possible into flooding that column.
And of course there's the question of "how are the results?" Are you getting off flavors through? Not high enough ABV? Is there a good reason you're chasing the semi-flooded condition?
Hope that helps.
TwoSheds

StillerBoy

Base on the statement about, how is your power managed, by a single pot or dual..
Mars" I know quite certainly that I myself have no special talent. Curiosity, Obsession and dogged endurance, combined with self-criticism, have brought me to my knowledge and understanding "
– Albert Einstein

TwoSheds

Base on the statement about, how is your power managed, by a single pot or dual..
MarsNot sure what you mean 'single pot or dual' but I use an Auber Instruments SSR controller that gives me 1% increments for power input. Even with that I find it fiddly to try to maintain a flooded column and it's easy to chase your tail.
With 5,500 watts I'm able to flood 18" of 3" column with Raschig rings, but that's a lot different from your setup. I'm looking for some SPP but if I can't find it reasonably in the US I'll get more Raschig rings so I can double that packed height for better output.

Salt-Must-Flow

I've been seriously considering SPP for years, but it's so expensive and most often not sized correctly for 3" columns as I understand it. I'm thinking about starting to make some, ordering 4 lbs of wire, making a mandrel, put it in a drill and just spin long coils to cut by hand over time. It shouldn't take long to make.
Traditional calculations say a 3" column should use .02"-.03" diameter wire. The link to the .035" is the cheapest wire I've been able to find. I figure the extra 5/1,000" extra shouldn't make a noticeable difference, but half the price of the .025" wire I've found.

TwoSheds

Can't say I haven't considered making it too. I even have a lathe with great speed control that would certainly suffice to wind it but I can't convince myself that cutting it is going to be any fun at all.

StillerBoy

I have no ideal what a 1% increment mean in relation to wattage, but a PID is not the best for distilling, yeah they do work for rough stilling, exactly as you have experienced,  but not for fine operation of distillation,..  dual mean dual potentiometer, a coarse and a fine, providing the ability to increase/decrease power by 50 watt at a time, and anything less or more will create control-ability..
Ditched the idea of raschi rings and SPP, and get 3/8" lava rocks, if you are to pack a 3", and be done and  set for life..
Mars" I know quite certainly that I myself have no special talent. Curiosity, Obsession and dogged endurance, combined with self-criticism, have brought me to my knowledge and understanding "
– Albert Einstein

Salt-Must-Flow

I have no ideal what a 1% increment mean in relation to wattage, but a PID is not the best for distilling, yeah they do work for rough stilling, exactly as you have experienced,  but not for fine operation of distillation,..  dual mean dual potentiometer, a coarse and a fine, providing the ability to increase/decrease power by 50 watt at a time, and anything less or more will create control-ability..
Ditched the idea of raschi rings and SPP, and get 3/8" lava rocks, if you are to pack a 3", and be done and  set for life..
MarsHe's using an Auber EZboil DSPR variable power controller. You can dial it from 1% to 100% power. If he's using a 5500W element then each % adjustment is 55W. It's a really great controller packed with a lot of useful features. Instead of actually varying the power like with an SSVR, it uses an SSR that pulses to vary the power.

TwoSheds

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What he said.
There's a big difference between a PID (on/off over the course of many seconds typically based on a temperature setting) and an SSR run by a purpose-designed commercial still controller (on/off many times a second based on a power setting.)
Mine's a DSPR400 if you want to read up. Overall it's treated me well.

StillerBoy

It's certainly not allowing you what you want the still to do from has been stated..  otherwise you would have manageability..
Pulsing is no different than running by temp in stilling, both disrupt the vapor behavior..
Each to their own I guess, and the enjoyment the issues created..
Mars" I know quite certainly that I myself have no special talent. Curiosity, Obsession and dogged endurance, combined with self-criticism, have brought me to my knowledge and understanding "
– Albert Einstein

Salt-Must-Flow

It's certainly not allowing you what you want the still to do from has been stated..  otherwise you would have manageability..
Pulsing is no different than running by temp in stilling, both disrupt the vapor behavior..
Each to their own I guess, and the enjoyment the issues created..
MarsYou are incorrect. It pulses ridiculously fast and provides smooth and repeatable control not affecting "vapor behavior". "As from what has been stated", you do not know anything about this specific controller, how it works, what it is capable of and have zero experience using it. "From what has been stated" even dual potentiometers aren't even capable of the precision in adjustment as the Auber unit. You've failed your critique on all counts.
You are comparing apples to oranges here bud and you are absolutely dead wrong. PIDs operate based on a set temp. PIDs fire the element at 100% power until the set temp is nearly reached (using a smart algorithm to then pulse as to not over shoot or under shoot the set temp). The Auber EZboil has nothing similar in how it operates.
Once again you're making baseless claims without ANY info to back it up.
Ask yourself this ... how is a PID capable of pulsing so fast that it can maintain 1/10th of a degree F within the boiler with such precision, BUT the Auber EZboil (not a PID) can't pulse fast enough so that it can smoothly VARY the power supplied to the boiler from 1% to 100% power? It is an objective fact that the Auber DSPR EZboil works. It's not even up for debate.Last edited by Salt Must Flow on Wed Sep 21, 2022 4:22 pm, edited 5 times in total.

shadylane

Decrease the takeoff rate, so there's more reflux.

StillerBoy

Maybe..  maybe not.. from all indication, not..  all I know and care about is the setup I got creates no issues, can hold SFS at 3/4" level for an hour, the best indicator for operating a reflux column at peak efficiency..
As to the others, their the one with the issues..
Mars" I know quite certainly that I myself have no special talent. Curiosity, Obsession and dogged endurance, combined with self-criticism, have brought me to my knowledge and understanding "
– Albert Einstein