Now turn those keg boilers 90 degrees please!

[Desvio]

I don't think that the conversion from liquid to vapor is happening at a fast enough rate where headspace or surface area is going to become a performance issue, now the headspace is going to remain the same by volume, however by spreading it out you are reducing the headspaces vertacle space bringing liguid closer to the vapor path into the still head increasing the chance of puking if it starts foaming on you.

[DAD300]

Evaporation happens only at the surface of a liquid and occurs at any temperature (so long as the substance is a liquid at that temperature). However, as most people are aware, liquids evaporates faster at a higher temperature.

Boiling, on the other hand, happens throughout the bulk of a liquid, usually starting from some site on the inside of the container (usually at the point of heat input, ala bottom of the keg) and rising in a bubble to the surface. It only happens when the temperature is above the boiling point of that substance.

or-

Evaporation occurs on the surface of liquid and it is a micro vaporization of liquid. Evaporation has a correlation between Temp and Surface area.

Boiling occurs on the entire mass of liquid and it is the macro vaporization of liquid. Boiling has a correlation between Temp and Mass.


There is no correlation between the boiling of a gas, to the size of the surface exposure.

[fyfo]

Mainly posting to dispute the puddle comparison. 2 puddles of equal volume but differing surface area would have different heat input, since the larger one gets more Sun.

I think even if there is a difference (which I doubt) it would be minuscule compared to minor differences in heat input.

Fascinating discussion everyone!

I agree with Angles explanation entirely. The spread out puddle is exposed to more heat so will of course evaporate faster (it is a red herring that there also happens to be more surface area).

I will also agree with Odin, BUT only if the keg is tipped onto its side and is heated externally with a large enough fire to cover it's entire lower surface area. Thereby exposing more liquid to be in contact with more heat (again the increased to surface area is a red herring).

I deem this to be a like for like comparison.

[ranger_ric]

I frickin Love Science....

Honestly I dont know a damn thing about it. However I LOVE reading the passionate beliefs and supporting arguments.....

Odin, I Love the Hand Grenades you throw into the mix. It stirs the pot and heats the boiler from the wrong side to bring about some really engaging thought!!

I am drawing out some plans and weighing how to get them (I am unemployed at this time) for a keg boiler wired for electrical..... This is fascinating discussion for me...
On my first read of Odins post it sounded reasonable to me... However thinking about "Science" it may not be as applicable as it sounds.....

Carry on my good friends. I am looking forward into some raids into mexico from the border here to capture some pinas from the agave plant....

WooooHooooo Good Conversation

[NZChris]

Put two cups on the table. One wide, the other narrow. Same amounts of water in them. See what's evaporated first.

And in a boiling situation: more disturbence in the liquid bath creates more turbulance to the gas bed, creating more (unwanted) reflux.

Odin.

I meant proof from the likes of a reliable physics text book. It is a pretty outrageous claim to make, so it's not up to us to disprove it, it's up to you to demonstrate that there is solid scientific theory behind it, and that you really can get something for nothing.

[LWTCS]

"I will also agree with Odin, BUT only if the keg is tipped onto its side and is heated externally with a large enough fire to cover it's entire lower surface area. Thereby exposing more liquid to be in contact with more heat (again the increased to surface area is a red herring). 

I deem this to be a like for like comparison.

Cheers, fyfo."


Totally flawed thinking and irrelevant.

An open flame will not heat a kettle charge more efficiently than an internal immersion element. The source of heat has nothing to do with the OP's assertion.





fyfoNovice 39 Sat Mar 14, 2015 12:37 pm Auckland, New Zealand

[aceswired]

Isn't evaporation just individual molecules gaining sufficient energy to turn to gas? The temp of a liquid is a measure of average kinetic energy. Within that is a wide range of individual kinetic values.

It's the same reason that when we boil, the stuff doesn't stack neatly according to boiling point. Otherwise, all the ethanol would be gone before any water. So the evaporating cups analogy is, in a way, analogous to boiling. But it ignores the fact that surface area is a big factor in low heat environments and of far less impact in high heat environments.

[rad14701]

The same heat input into the same volume of the same constituent mix in the same sized yet different shaped boilers will produce distillate vapor at the same rate... The main difference is the distance the azeotropic molecules have to rise through the volume of liquid and how much head space there is to be filled, potential fraction stacking, and perhaps surface related condensation reflux...

Yep, we've been here before...

[FullySilenced]

Thank you RAD... I know i have read this discussion a couple of times...

[Saltbush Bill]

Only a couple of times Fully? The subject has been done to death on ever distilling forum around at one stage or an other. The end result is always the same, Surface area makes no difference.

[ga flatwoods]

Odin and others,
I care not to discuss the science of the issue at hand but offer up this thought. Especially for those using gas as a heat source, the bottom shape and ring of the typical boiler keg is much better at receiving the heat source and keeping it where needed than would be the keg laid on its side. The heat would tend to roll around the edges and deflect away more from the surface making it much less efficient. Unless, of course, the keg were modified with longitudinal plates to help contain the heat. Even at that the mdifications necessary to make the keg user friendly from the side would be cumbersome for most folk. Look how many dont go electric now due to the welds and modifications required.
it has been years ago now but I did once run across a very in depth discussion about circumference verses height on boiler construction. I forget the small details but it was always a more narrow bottom dimension than height dimension (ie taller than wide as is a keg). However, picture the old timey moonshine copper, large capacity still with worm coiling out of the top and more than likely the bottom is smaller than the circumference near the fill line. I like my vertical keg.
Ga Flatwoods

[fyfo]

"I will also agree with Odin, BUT only if the keg is tipped onto its side and is heated externally with a large enough fire to cover it's entire lower surface area. Thereby exposing more liquid to be in contact with more heat (again the increased to surface area is a red herring). 

I deem this to be a like for like comparison.

Cheers, fyfo."


Totally flawed thinking and irrelevant.

An open flame will not heat a kettle charge more efficiently than an internal immersion element. The source of heat has nothing to do with the OP's assertion.





fyfoNovice 39 Sat Mar 14, 2015 12:37 pm Auckland, New Zealand

We are all on here sharing our opinions and theories. Some are based on sound knowledge and some are not (that's the fun of it I guess!) The number of posts a user has (and his site determined "rank") is not in any way related to whether their post is worthy of your approval. You do not know my formal training, or what I've read or my level of intelligence etc etc etc... I could indeed be thick, or I could indeed be a science professor, the point being you have no way of knowing this.

Perhaps you would prefer a filter that allows you to not have to bother with us low down on the sites food chain! Ha!

But seriously, if you wish to encourage new members, or you wish to encourage friendly discussion (and by the way I don't determine your post as being that), then throwing in someone's "status" as a factor to strengthen your case, then what on earth does this site exist for?

[LWTCS]

Hi fyfo,
Your right and I do apologize for coming off that way.
In hindsight, I think I was just really surprised that we were hashing this subject matter out again with some senior members here not quite understanding how this particular concept applies in practice.

After re reading I can see that my manners were not good at all.

[fyfo]

Thanks LWTCS apology accepted. I can understand how it might be frustrating to rehash these topics over and over and perhaps you even see the same responses too

[pfshine]

He might have come off harsh but he was right. The logic stated was flawed. I'm not trying to be mean either. Sometimes flawed thinking or ideas can steer new guys in the wrong direction. Fact is open surface area of the liquid has nill to do with boiling.

[thecroweater]

He might have come off harsh but he was right. The logic stated was flawed. I'm not trying to be mean either. Sometimes flawed thinking or ideas can steer new guys in the wrong direction. Fact is open surface area of the liquid has nill to do with boiling.

+100% ,I came across two old threads just like thislooking for some guys post a few years back,.same for stearing noobs in the wrong direction ,this sort of bull was the gossip back when I was lurking

[S-Cackalacky]

I don't know which is worse - Odin posting this topic, or us seriously discussing it. But then, I guess it needed to be seriously discussed so as not to corrupt the knowledge base.

[raketemensch]

Whatever the outcome, it was a question worth asking.

[LWTCS]

Whatever the outcome, it was a question worth asking.

But see that's the thing....the question was not asked at all.

Simply read the OP and the OP'S forthcoming rebuttal and all that it implies.

[pulsetech]

Whatever the outcome, it was a question worth asking.

But see that's the thing....the question was not asked at all.

Simply read the OP and the OP'S forthcoming rebuttal and all that it implies.

I Agree it was a Statement not a Question as was the title. Its Almost a Troll TBH

[Titus-a-fishus]

I'm sure Odin enjoys stirring the pot....

Some years ago I thought similar, but in relation to fermenters.
If you have a larger surface area in your fermenter it should ferment quicker.
Yeast gets started quicker etc.... or so I thought.

Did the experiment using a normal 30 ltr fermenter with a narrow top, a 30ltr fermenter with a wide top and a large storage box wide at the top 80ltrs.
Result?
They fermented out at almost exactly the same time.

Not quite what you are discussing here but it is relating to surface area making a difference.
It doesn't

And for the record....
I run my keg sideways.
It's a more stable platform.
Can't say it works any better or worse as I haven't got an upright keg of the same size to compare with.

Only doing the experiment will give you a definitive answer... though I'm sure there are those here that will argue about that as well.

TAF

[Titus-a-fishus]

Seriously Odin, what have you got in store? A 90 degree keg based hydro separating Istill?

I might be dumb, but I'm not stupid...

Remember awhile ago Odin... you were putting it out there that a copper still wasn't good for your health, stainless steel was the only way to go?
http://homedistiller.org/forum/viewtopi ... =1&t=42610

Perhaps we will be seeing some new items on your for sale list???

I like you mate but.... refer to Emptyglass quote.

TAF

[NZChris]

Only doing the experiment will give you a definitive answer... though I'm sure there are those here that will argue about that as well.

Those experiments have already been done for us. Look up 'latent heat of evaporation' in any physics textbook.

[Tokoroa_Shiner]

Distillation as been around for so long that if there was any validity to it, then we would already be doing it.

[Titus-a-fishus]

Only doing the experiment will give you a definitive answer... though I'm sure there are those here that will argue about that as well.

Those experiments have already been done for us. Look up 'latent heat of evaporation' in any physics textbook.

That's the point.
If the experiment has been done and proven....
What more is needed to be said?

[MoonBreath]

Odin, is there something we're all missing here?
Are you planning on releasing a re-designed horizontal version of your infamous set and forget, heartcut only producing, Pulitzer prize winning istill?
Let us all know when they're ready..We all may want to scrap our junk.

[thecroweater]

We got these old barrel shaped 18 gal kegs and they have a threaded bung in the middle . Lots of guys have ran them side on with a column screwed into the bung with no issues. Ppl who think they run better that way might be right..... and then again they could be left, they run the same

[Odin]

Hi guys, glad I got your attention! Okay, I will be honest, I sorta expected the remarks about keg boilers to raise the room temperature, since so many use them. And if you build it, and if you like running it, who the heck needs a weird Dutchman to tell you you are doing it upside down (well, sort of ...). Hell, he even claims he lives 3 feet under sea level! Hmmm ... well, actually I do. And my post on boiler design is no fake either.

So, if I may ask a bit more of your time and energy (pun intended), boiler designs matter. In fact they hugely impact total still performance. It's about boiler roof shape, about temperature delta's between the roof and the gasses inside the boiler (on top of the liquid bath ... and it is about how wide versus how narrow a boiler is.

Let's start with that last point and please stay with me.

Take two designs. Both can hold 13 gallons. That's gross. One design is higher and more narrow in shape. The other is wider and less tall. Now, both have the same column on top of them. We don't want to go there, right now. I have some interesting stuff on columns as well, but I am affraid if I dish it all out in one go, you will send the mob squat over to my place ... so let's focus on them boilers.

Both of them are heated by ... well, let's say a 4 kw electric heating element. Doesn't really matter, as long as they have the same power input and power input system. They do. At least in this example.

Okay, we fill each boiler and start to heat up. After some time the contents of both boilers get to a boil. Let's say we keep on using 4 kw. Just for examples sake. That's 4 kw being fed into both systems. "Power in is power out?" Yeah, but ... let's zoom in on the top of the liquid bath. The narrow boiler has a total surface area (where gasses boil off) of 1 by 1 foot (just making things up here, so don't crucify me by stating that's our of the ordinairy, please). The other boiler is wider. Say 2 by 2 feet. A simple computation means that the total surface area (in this example) of the still with the wider boiler is 4 times bigger than the still with the narrow boiler.

Now, they both get 4 kw fed into them. They both boil. So, they both create an x amount of 4 kw in gasses per whatever time slot you choose.

But with the narrow boiler that 4 kw of energy coming off over a surface area of 1 foot, where the liquid bath in the wider still has 4 times more surface area. The wider boiler releases less watts per square centimeter or millimeter or whatever unit you want to pick.

The wider boiler releases less watts per square centimeter ...

That's like saying the boil is more gentle. Much more gentle, actually! If the boil up (liquid levels that raise and fall due to the boiling action) is like an inch in the wider system, it may well be 4 inches on the smaller diameter boiler. In fact, the boil may be so violent that liquids is flying all around ... and especially through the gas bed on top of the liquid bath.

Now, let's change one thing. Let's make both boiler designs not just 13 gallons gross, but 13 gallons nett. The boiler with wider design, that facilitates a mellow boil may probably need to be as large as 15.5 gallons gross (83% filling rate or something like that). The more narrow design needs to be something like 18.5 gallons.

To compensate for high energy release in the liquid bath, more narrow boiler designs need to have more head space. Okay, some simple math again ... and 18.5 gallon boiler is bigger than a 15.5 gallon boiler. About 20% more material involved. That's material that needs to be made, bought, formed into a boiler. And it is material that continuously needs to be warmed during the distillation run. For no obvious reason, other than temperature loss. Just some shitty calcs again. Say a boiler weights 20 kilo's and the more narrow design therefore 24 kilo's. Total wash weight 48 kilo's ... that's 68 kilo's total weight for the wide system and 72 kilo's for the more narrow system. So ... by choosing a wider design (AKA a more optimized design) for our boiler, we just created an energy gain of close to 6%. Turn that around: 6% slower runs. Or 6% less output. And that's just from material heat-up and keeping that material warm. There is more, that makes the advantage of a wider design much bigger. Turbulence in the more narrow boiler creates more aerodynamic drag on the gasses trying to reach the column entrance. Drag leads to (slight) overpressures. And overpressures (and liquids flying through the not so stable gas bed) create unwanted boiler reflux. Boiler reflux? Yeah, shit falling back into your distillers beer instead of making it to the column.

On the tests I did with more narrow designs and wider designs, I find total differences up to 20%. That's with insulation and boiler roof slopes optimized. Not saying beer kegs have optimized boiler roof slopes. Pretty sure most of them don't have insulation.

Regards, Odin.

[Titus-a-fishus]

Hi guys, glad I got your attention!

And my post on boiler design is no fake either.


Take two designs. Both can hold 13 gallons. That's gross. One design is higher and more narrow in shape. The other ... so let's focus on them boilers. OK apples with apples

Both of them are heated by ... well, let's say a 4 kw electric heating element.
Still with you

That's 4 kw being fed into both systems. "Power in is power out?" Yeah, but ... let's zoom in on the top of the liquid bath. The narrow boiler has a total surface area (where gasses boil off) of 1 by 1 foot (just making things up here, so don't crucify me by stating that's our of the ordinairy, please). The other boiler is wider. Say 2 by 2 feet. A simple computation means that the total surface area (in this example) of the still with the wider boiler is 4 times bigger than the still with the narrow boiler.
Now we are into theory land as this isn't a proper comparison of two actual boilers. You don't know the actual surface area of these two boilers that now are orientated differently.
Benefit of the doubt though.

Now, they both get 4 kw fed into them. They both boil. So, they both create an x amount of 4 kw in gasses per whatever time slot you choose.

But with the narrow boiler that 4 kw of energy coming off over a surface area of 1 foot, where the liquid bath in the wider still has 4 times more surface area. The wider boiler releases less watts per square centimeter or millimeter or whatever unit you want to pick.

The wider boiler releases less watts per square centimeter ...

That's like saying the boil is more gentle. Much more gentle, actually! If the boil up (liquid levels that raise and fall due to the boiling action) is like an inch in the wider system, it may well be 4 inches on the smaller diameter boiler. In fact, the boil may be so violent that liquids is flying all around ... and especially through the gas bed on top of the liquid bath.
I see what you are aiming at, you are looking for a less violent boil. That says to me that the type of boiling action is what you think is optimal and that is influenced by the boiler surface area.


Now, let's change one thing. Let's make both boiler designs not just 13 gallons gross, but 13 gallons nett. The boiler with wider design, that facilitates a mellow boil may probably need to be as large as 15.5 gallons gross (83% filling rate or something like that). The more narrow design needs to be something like 18.5 gallons.
So now are you comparing just surface areas, the boilers are no longer similar. You've now lost me.
Your thread was about turning your boiler sideways to get better performance. Just turn your keg sideways and you will get a performance gain.... OK most blokes use a 50ltr keg
What performance gain is there in taking a 50ltr and turning it sideways?
Have you done a comparison as you set out above to check that what you are saying is correct?
If so - please give us the results and a photo of the kegs in action.


To compensate for high energy release in the liquid bath, more narrow boiler designs need to have more head space. Okay, some simple math again ... and 18.5 gallon boiler is bigger than a 15.5 gallon boiler. About 20% more material involved. That's material that needs to be made, bought, formed into a boiler. And it is material that continuously needs to be warmed during the distillation run. For no obvious reason, other than temperature loss. Just some shitty calcs again. Say a boiler weights 20 kilo's and the more narrow design therefore 24 kilo's. Total wash weight 48 kilo's ... that's 68 kilo's total weight for the wide system and 72 kilo's for the more narrow system.
Hang on - you are now running a smaller boiler and a larger boiler on the same 4kw elements. Of course there is going to be an energy loss difference. Now we are into the apples and oranges scenario. Your logic is flawed.

So ... by choosing a wider design (AKA a more optimized design) for our boiler, we just created an energy gain of close to 6%. Turn that around: 6% slower runs. Or 6% less output. And that's just from material heat-up and keeping that material warm. There is more, that makes the advantage of a wider design much bigger. Turbulence in the more narrow boiler creates more aerodynamic drag on the gasses trying to reach the column entrance. Drag leads to (slight) overpressures. And overpressures (and liquids flying through the not so stable gas bed) create unwanted boiler reflux. Boiler reflux? Yeah, shit falling back into your distillers beer instead of making it to the column.
Apples and oranges, doesn't count as a fair comparison.

On the tests I did with more narrow designs and wider designs, I find total differences up to 20%. That's with insulation and boiler roof slopes optimized. Not saying beer kegs have optimized boiler roof slopes. Pretty sure most of them don't have insulation.

It has always been known that a larger head space even in pot stills gives passive reflux. This isn't related to the vigor of the boil as you are saying earlier in this post. You've gone from same sized boilers with same input but change of orientation to different boilers same elements, no longer a fair comparison.

The differences in 50ltr boilers turned side on should be enough to convince the majority.
So apples with apples and take the results from that. You've run ahead of yourself Odin and missed where you left the fair comparison.

Regards, Odin.

Not convinced Odin.
You need to make fair comparisons.
TAF

[Odin]

Hmmm ... I thought I did by taking nett wash as a starting point for fair comparisons ...

Odin.