Lets Talk Column Packing

[thecroweater]

Yes i guess everyone is comfortable with different products , I myself would not be overly concerned with the impurities of coking coal (not petroleum coke) as it needs to be almost free of any impurities to be used for its main purpose in forges and blast furnaces for the production of steel iron stainless ect . The coal is cooked to remove impurities for this end and has only trace elements of sulfur , hydrogen ect as so would my copper or my wash . Lava stone (scoria , pumice ) would likewise be very high in carbon with a number of other elements . most of this type of product round here anyways would be perhaps millions of yrs old and surely any volatile or disolveable compounds would have long ago leached out , I can't comment on raschig rings as I have no idea of the compounds used in their manufacture
OFF TOPIC @ MR : Chicken , Bald Eagle ? Nar more like a mix of vulture and magpie ha just means someone from South Australia (to do with a famine in the 1830s)

[Prairiepiss]

Something else to consider. Yes you may be getting good results from lava rock in your 4". But can the same results come from a 2"? I've read in a few places where lava rock had been used. But was considered inferior in efficiency compared to say scrubbys. Those test would have more then likely been made on a 2" column. As it was the norm up until fairly recently for hobby scale. So maybe there is more to the size of the column? Maybe the bigger mass in a 4" has something to do with it?

It's been said for a long time structured packing like scrubbys doesn't work good in columns over 3". So maybe somewhere between 3" and 4" it flips where scrubbys don't work anymore but the lava rock does?

I'm just going by information I read a long time ago about lava rock. And I can't for the life of me remember where I read it? And who knows if it was accurate? But its worth a thought or two.

[cob]

BTW, Does crow taste like chicken? Bald eagle?

OFF TOPIC @ MR : Chicken , Bald Eagle ? Nar more like a mix of vulture and magpie ha just means someone from South Australia (to do with a famine in the 1830s)

the northwestern crow (USA) with proper and careful preperation tastes just like spotted owl.

[Dnderhead]

I whould think with retaining heat you could make the column taller therefor more/better separation.
with a short column this mite not be practicable,the whole column/packing whould tend to heat the same.
posably with a "short" column you whould want a packing that does not retain heat and when using a tall column you whould.??

[Prairiepiss]

I think you have a good point Dnderhead.

If you combine that with what I said about it working with the larger diameter column could hold true to this thinking to? Possibly bigger diameter shorter hight would need a packing that would dissipate heat quicker?

Not trying to take this thread off Target. But this could answer some questions of why the inline thumpers under a shorter packed section are working so good. The inline thumper is making a temp barrier so the packing isn't getting so much to shed. So less height is needed. Sory trying to equate how this could help my experiments.

[Odin]

I spoke to a guy in Poland about supplying me with SPP. He asked me: "what is the diameter of your column?" I asked him why he wanted to know that, and he said it is because for bigger diameter columns bigger sized SPP works better.

If that is true, a bigger sized packing than scrubbers should work better in a bigger diameter column ...

Odin.

[Bushman]

I spoke to a guy in Poland about supplying me with SPP. He asked me: "what is the diameter of your column?" I asked him why he wanted to know that, and he said it is because for bigger diameter columns bigger sized SPP works better.

If that is true, a bigger sized packing than scrubbers should work better in a bigger diameter column ...

Odin.

Interesting, I would like to know the science behind that statement!

[Prairiepiss]

There has always been talk about the size of SPP compared to the column diameter. There was a formula for determining the size of wire and the diameter of the SPP coil by the column diameter. I think 2" they used .020 to .022 wire on like an 1/8" mandrel. Then I think they stepped up to a .030 to .035 wire with a 1/4" mandrel for 3" columns. I even seen something about a .040 to .045 wire for bigger columns. Don't quote me on those numbers. Just going by my horrible memory. I chose .020 for my 2". And when I get it I will use a 1/8" Manuel. To make it. But I have to wait a little over a month for the wire. So I think that will be a winter project.

[mash rookie]

Packing allows you to achieve greater distillation cycles with less reflux ratio because of density or greater surface area.
Surface area = evaporation surface. How long will it take for 1 cup of water to evaporate in a tall skinny glass as compared to spreading it out over a large surface? Simply, the greater the surface area the easier the evaporation.

No. You dont need larger packing in a larger column if its structure is capable of supporting its own weight without collapsing and causing choking. To use larger packing could defeat the goal by reducing packing surface area.

What I have shown is that you can achieve high purity in a relatively short column if the surface area is great enough to provide a very low HETP. The larger diameter allows for reasonable take off speed without severe disruption of column equilibrium.

I am going to speculate that using a packing that does not transmit heat well may provide a more stable equilibrium. Once warm It is not prone to temperature swings that affect fractioning as liquid is removed. We know that column insulation improves distillation because of reduction in wall affect. Reflux is kept more on the packing were it moves down slower and enjoys more evaporation cycles.
Using material that has a soft surface allows liquid to cling to it and evaporate instead of dripping off. Greater evaporation cycles.

PP, You will have to pickle your SPP for a dull porous surface. SPP shape will allow for very dense placement without choking. BTW. You might try Alaskan Copper and Brass for your stainless wire.

[Max_Vino]

Mash Rookie
Thank you for presenting your research. I found the information you presented is some of the best reading on this site and I look forward to seeing how this progresses.

What I have shown is that you can achieve high purity in a relatively short column if the surface area is great enough to provide a very low HETP. The larger diameter allows for reasonable take off speed without severe disruption of column equilibrium.

This is what it's all about…surface area. Greater surface area is achieved by the "wet-ability" of the substrate. If you place a lump of lava rock in a shallow dish of water alongside of a glass or stainless steel marble you can see the water climb the sides of the rock and not the glass. Even worst the water will trend to bead on a glass surface. (check out high energy surfaces vs low energy). so if you had two columns with the same SA the lava would present more liquid to the vapor stream than marbles.

(

I am going to speculate that using a packing that does not transmit heat well may provide a more stable equilibrium. Once warm It is not prone to temperature swings that affect fractioning as liquid is removed.

I think the issue of thermal conductivity of the packing is moot. A insulated column is mostly adiabatic and the phase changes are powered by the vapor stream and limited to surface effects.

I think the next part of the process is to size the rock, keeping in mind the interstitial spaces between the lumps…so you will need to screen for two or three sizes. Depending on how your tests go I would think a small business could be made selling rock for this purpose. I wouldn't worry about contamination like arsenic, as metallic ions they will not be carried over in the distillate…entrainment is another issue.

Cheers,
Max

[mash rookie]

Goodness, Very nice first post. Welcome aboard Max! I am happy to see I get some peoples attention. Particularly those that understand. I always wonder how many are reading along.

I think the issue of thermal conductivity of the packing is moot. A insulated column is mostly adiabatic and the phase changes are powered by the vapor stream and limited to surface effects.

I noted a couple of posts ago that surface effects and density of high efficiency packing may out weighs thermal conductivity concerns.

Greater surface area is achieved by the "wet-ability" of the substrate.

I think that is why some have had sucess with pottery or raching rings and why I treat copper and stainless with acid.

Entrainment is not an issue with dense packing that has high evaporative qualities. In a sense it is solved by the additional evaporation cycles. Channeling is always an issue and can be addressed by sizing the stone.My recent test was done without sizing. I did make an effort to pack it tightly by filling slowly and tapping my column gently with a hammer.
I still dont know how tight I can pack it and still maintain vapor speed and a similar reflux ratio. I am hoping to find the efficiency sweet spot with lowest reflux ratio and optimum take off speed.That will provide the lowest power consumption.

Stick around Max. You will fit right in!
MR

[Max_Vino]

Entrainment is not an issue with dense packing that has high evaporative qualities. In a sense it is solved by the additional evaporation cycles.

Entrainment in the distillate is a result of high vapor forces (mass x acceleration)..in commercial pilot operations the packing is often screened down to prevent it from flying up into the condenser...( I have seen this happen). An easy way to check for this it called the "Tyndall Beam method (or effect)" ...place you distillate into a clean beaker and shine a bright collimated light (like a par spot)...you should be able to see particles on the order of a single wavelength..your distillate should be crystal clear...maybe a few floaters...more than that an you have a problem.... but I warn you, I once set my feet on fire trying this.

I am hoping to find the efficiency sweet spot with lowest reflux ratio and optimum take off speed.That will provide the lowest power consumption.

Ahhh...well this brings us to THE question...all of your graphs to find the sweet spot will relate to "your" still configuration, and the operating parameters you set, which will culminate in a % of purity. Assuming a water, sugar, yeast wash....what percent ? 90 ?...92?....95? Tell me Mash, how are you going to arrive at this number ?

Max

[mash rookie]

Ahhh...well this brings us to THE question...all of your graphs to find the sweet spot will relate to "your" still configuration, and the operating parameters you set, which will culminate in a % of purity. Assuming a water, sugar, yeast wash....what percent ? 90 ?...92?....95? Tell me Mash, how are you going to arrive at this number ?

One design at a time. I am working on four inch columns and will work on six inch next.

The simple answer is I want to produce 96% at best possible speed with lowest BTU input possible and lower ABV 85% at rocket fast speeds. I will work backward from these numbers. A truth in the hobby world is that most dont care about power consumption and will run a very high reflux ratio to get higher ABV without fractioning concerns. I am trying to understand the big picture. Micro distilleries will care and want to know real numbers. I want to build a still that is truly versatile.

Unfortunately Max I am going to do it like a gear head. By trial and error (failure), documenting results and attempting to make sense out of them. I try to make one change at a time and do comparative tests so there is some value to them. Vapor speed, wash ABV, and reflux settings are constants when doing packing tests.

Vapor, Liquid, Equilibrium graphs are flying right over my head trying to do the calculations. Particularly with an azeotrope compound . I need to break out a high school algebra book and learn math again.

I know all the information is at my finger tips. I am just not knowledgeable enough interpret it correctly or put it to formula. I am learning a lot but dont want to draw incorrect conclusions.

Known starting ABV. (not sure this maters recently)

Known power in. Watts @ 4” = vapor speed

Take off speed = reflux ratio when subtracted from vapor speed.

Final ABV. = Total theoretical plates.TTP

I am not sure how to determine equilibrium ratio until I can master the graphs. This may be as simple as TTP/Hieght?

I have noticed some interesting things lately that I want to prove or disprove. One, a four inch column seems to be limited to about a gallon an hour give or take some variables. (although recent tests showed faster speeds)
Two, starting ABV does not seem to play a role in column performance. That is contrary to thinking at this site but is something that has been showing in my tests. Conventional wisdom states that the column will perform better with a higher starting ABV because it does not have to do as much work. In some of my tests I have increased starting ABV with the same still configuration without change in performance.

Its all fun and games till someone burns their shoes!!


edit; to add. The information that I am able to learn should transfer to my larger stills. Similar vapor speeds should apply to similar packing protocols and reflux ratios. The height to width ratio increase should improve take off without diminishing returns.

[HookLine]

something that mite work ,,there is a copper "foam" type of material.I have no idea what its called.but its copper that is full of bubbles/holes like a sponge.

found some others out there,,http://www.ergaerospace.com/images/ERG% ... ts%202.pdf

Nice find, sir.

Can you imagine being able to buy a single large cylinder of that stuff, just the right size to be a perfect fit inside your column, simply slide it in and out in one go... Fantastic.

[Dnderhead]

i had a bit of brain storm..if you had disk of the copper that fit in column. place a disk.spacer disk,,,

", simply slide it in and out in one go...(used to be that way ) that could be done with most packing
just make a "cartridge" similar to what a grease guns takes.

[mash rookie]

Myles recently built a packing cartridge. I dont think we want a spacer. That would work kind of like putting packing on top of a flute plate to stop entrainment.
I think we would be wasting valuable space that could be providing additional evaporation cycles. A packed column is taking advantage of every inch available.

I would love to get my hands on some of that copper for testing. It might be too tight to use as a disc or inserted solid piece to let vapor flow. If it was sized in small chunks I think it would work better.

RC mentioned using pumice discs. Those may be too dense as well. My thinking is that we need small individual packing pieces with massive surface area. They should then be packed perfectly as to allow vapor to contact every surface and flow freely without enough space for liquid to channel and run. Liquid should flow like a sheet weeping down packing. No drips. No runs.

[Prairiepiss]

My question with the lava rock type open cell packing. It seems from the discussion that it is thought the vapors will be traveling through the pieces of packing. Is this really what is happening? I would think the individual chunks of say lava rock. Will fill with liquid like a sponge. And the vapors will only be traveling around them. So although it has a greater amount of surface area. That surface area is split up into to parts. One liquid only contact area. This would be the inside of the rock. And one vapor liquid contact area. this would be the outside surface of the rock.

Now the outside surface area being porous will hold more liquid in place for the vapor to interact with. And the liquid within will have a chance to migrate towards the boiler. Reflux collecting on top of the rock will move either through or around and down the rock. Rising vapors and pressures would help the rock contain the liquid. So basically the surface of the rock will hold more liquid for a vapor contact area. Compared to a flat surface which will only wet with the liquid.

The rock being pours filling with liquid will now take on the thermal properties of the liquid within it. Or at least a portion of both the liquid and rock material. But in the case of a lava rock. I would expect there would be very little rock mass compared to liquid mass. I could be wrong on that?

Sory just something that I've been thinking about. And needed to post it. What are others thoughts on this thinking?
What is actually going on inside the rock? Compared to packing like Scrubbers?

Edited to add. The outside of the rock being the only surface area in contact with the vapors. This mite be why it works better in the larger diameter columns. Where in the smaller ones you can't get enough in the space provided. This mite just be a little part of the whole thing?

[Dnderhead]

i thank the rock is "closed pours" when its crushed/cut it exposes the nooks and crannies.
so the rock does not "soak up " the distilled but instead "holds it"

[mash rookie]

You are correct PP, Dndr. I doubt any liquid is penetrating or flowing through the rock. It is all about the surface. When watching refluxing in a glass column you only observe the liquid behavior. Evaporation is invisible to the naked eye and is assumed. The lava wicks more slowly than the stainless wool and flows well where packed tightly. Open areas did have channeling occurring.

I just had another thought. When working on my boat BBQ last night I noted that the lava rock exposed directly to the burner had turned white. What does this mean? Heck I dont know but It gives me another experiment. I will weigh up a couple of pounds to .001 and heat it in one of my furnaces to 2000 degrees for 30 min. Will it turn white? Will it be lighter. Will it be more porous? I think charcoal is activated by a high heat process. I will make sure it is bone dry by baking at low temps first. I could also measure liquid retention before and after by weighing. I could measure density by displaced volume.

Crap. I could spend a whole day playing with two pound of rocks. Remember the saying “Dumber than a box of rocks”? This idea might be.

[Prairiepiss]

I was thinking yes you could do a displacement test. But this would only give you the volume of rock. When in use in a column and the vapors traveling through it. How could we determine the displacement. As the rock would retain liquid. Making its mass bigger. And no real way to measure how much that would be? Or at least I can't think of one. How do you measure the mass of a rock filled with liquid? When it will just run out?

[Dnderhead]

when charcoal/activated carbon is made it is "destructive distilled" this is heating in a inert atmosphere,to vaporize the "softer" material.leaving the carbon.then "washed".
coke is done similar.coal is heated.leaving a high carbon content.burning off gases or collecting for future use.(coke can also be found naturally.this similar but by volcanic action)

[Dnderhead]

"measure the mass of a rock filled with liquid"
you whould measure the liquid..place "rocks" then remeasure.the "rock"will displace its volume.
only thing is trapped air.

[Prairiepiss]

Yes dunder that would give you the mass of the rock itself. + whatever air was trapped in it.

But I was asking how could you get the mass of one rock combined with the liquid trapped within it. As it would be during a run. Maybe its not a need to know measurement. But I would think it mite be? Seeing how that's how it will be wjen the still is running.

[mash rookie]

Information is most usable for comparison of different materials. Really good stuff to know when doing direct comparison tests. I would love to test for a month then sit down and sort out the numbers.

By measuring the weight of the rock and water before and after you can determine the amount of surface retention. Good info to know. Static retention or “wet-ability” is important. It is a direct measure of packings ability to perform.

Knowing the maximum density possible for a given vapor speed would be good to know. Denser means more surface area per unit measure. There will be a balance between density, vapor speed and reflux ratio. You can only do so much with a given space. Look at just a 6” slice of a column. What percentage should be packing, vapor space and liquid space?

By measuring the liquid volume displaced by the rock will give you direct density per unit measure.
Example; total area of a six inch column, six inches high is 3 x 3 x 3.1415 x 6 = 169.6 cubic inches.

A twelve inch piece of glass tube would be a great tool. Add 6” of water and remove. Instal six inches of packing to be tested and re-instal the water. Simple measurement of liquid height above the packing will determine displacement using basic math.

Unfortunately I have more ideas than time. Time to go sit in the sun and drink a beer.

edited; I think I was drinking when I posted this yesterday. I corrected some wording to not sound so stupid.

[mash rookie]

Foolin around on my boat I found a bag of BBQ lava rock. This is stuff that I used in my Keg BBQ. It is larger but considerably lighter than the decorative red rock lava that I used.

I took a piece out on the dock and smacked it with a hammer. It is much softer and crushed easily. It is dark brown or black in appearance. It looks much more porous than the red lava. I have been planning on rock shopping when I return from vacation. This will definitely be on my list to buy. It will be easier to size it down to increase density.

I will of course have to test it in the four inch column with the same power and coolant settings. Damn. I am dying to run the six inch.

[Odin]

6 inch .. allmost industrial size. What do you expect to get out of it? Like 2 gallons an hour, right?

Mash, when testing lava rock, did you encounter any problems like the stones expanding under heat ...?

Odin.

[mash rookie]

Odin there were no expansion issues that I can report. I did COE tests on the glass, stainless and copper that showed very little expansion at these low temps. I would expect that if there was any significant packing expansion I would have had issues in the glass column.

Speed on my six is yet to be determined. Volume is more than double so yes, I expect two gallons an hour approximately. Maybe slower at 96.5% ?? A very good reason to be anxious to do testing. Yes, I am working on micro distiller designs. I doubt hobbyists will want to pay what I would charge. I am going at things a little differently. Once I have perfected an efficient neutral column, I will design a de-tuned system for making whiskeys, rum and brandy. Eight inch tests next year?

[myles]

I have to admit that I do like the idea of a "cartridge " type packing utilising loose packing. I am still not sure about the relevance of a porous material, but I am willing to be open minded.

So how about a perforated cylinder to slide into your column? Perforations just small enough to prevent the packing falling out. You could build them in say 12" lengths if you wished to use different packings. A small version of a gabion filled with basaltic pebbles (just as an example) for instance. Just as a mechanism for retaining the packing and stopping it going all over the floor during removal.

Someone else mentioned a modular column, which is a good idea too, I am just thinking of ease for experimental purposes.

[Bushman]

Myles my mind has been rapped around this concept for about 3 weeks. I have been reading Kister's book Distillation Design and he devotes almost 100 pages (1 chapter on Packing Design and Operation) then the next chapter goes into Packing efficiency. I had no idea that there are already so many different types of designs and materials for packing. It is an interesting book as prior to this chapter several 100 pages are dedicated to Tray design and operation and tray efficiency. I understand it a bit more as I have given up on the post graduate math calculations to compare designs and just concentrated on the design itself and it's comparisons.

[mash rookie]

Until I saw SPP I had never considered pour in packings. I have read about copper and ceramic pour in packings as well. They are really easy but they still have to be installed correctly.

Myles, I like your idea for providing a product to people. My take on it would be to build six inch sections using stainless screen. Make a ten inch long cylinder. Fold one end closed. Place it in a six inch piece of scrap pipe. Pack tightly and fold remaining end closed. Ship with rubber bands or cardboard wrap. People could slide in as many sections as necessary.
How would this change wall affect channeling? Make it better or worse? Would we loose efficiency or have choking at section butts?
My thoughts are that sections like this could be helpful by directing liquid away from the wall and centering it at the folded ends

What about packing sets for vodka and a different sets for rum? I dont think that will be necessary but??

BM we are just scratching the surface. The commercial guys have been studying packing for a long time. There is a whole world beyond scrubbers. What will work best for our size, speed and desired product? I am not sure but am going to keep an open mind. Keep your eyes open for something that might work.