Boiler surface area vs production rate

[ShineonCrazyDiamond]

This discussion sounds familiar.
There may be some info in here: http://homedistiller.org/forum/viewtopi ... 88&t=57353" onclick="window.open(this.href);return false;" rel="nofollow

"Do not fear to be eccentric in opinion, for every opinion now accepted was once eccentric."
-Bertrand Russell

[DirtyOz]

The evaporation rate is exactly what I was trying to compare. The surface area I was referring to is the exposed surface of the liquid. I do understand that different types of “alcohol” boil at different temperatures, and that more heat equates to higher off gassing of vapor. If the whole volume of liquid is heated to the boiling point of the desired alcohol within, does that mean more vapor in a larger vessel of the same diameter. Of course I could turn up the heat, but I don’t want to increase the water vapor to point where it is considered undesirable.
It’s obvious I have a lot to learn, and I am definitely getting an education from all of you. Thank you for that guys.
I just thought of another question. Let’s say you have 3 gallons of stripped alcohol at an abv of 65%. You dilute it with 1 gallon of added water for the spirit run for a total of 4 gallons. Then you compare that to the same abv with 2 gallons water to a total of 5 gallons. Using the same still, how would they compare In the end if you ignored heat up times?
On the few runs that I have done, I’ve always just aimed for a semi steady stream out the end.

Oz

[still_stirrin]

... Let’s say you have 3 gallons of stripped alcohol at an abv of 65%. You dilute it with 1 gallon of added water for the spirit run for a total of 4 gallons.

Then you compare that to the same abv with 2 gallons water to a total of 5 gallons. Using the same still, how would they compare In the end if you ignored heat up times?

So, 3 gallons @ 65%ABV = 1.95 gallons of (theoretical) 100%ABV.
If you dilute that with 1 gallon of water, it becomes 1.95 / 4 = 48.75%ABV.
But dilute it with 2 gallons, and it becomes 1.95 / 5 = 39%ABV.

How would they compare....what do you mean?

The undiluted low wines is too high to run at 65%ABV. Even the 4 gallon low wines is on the higher side to run, but it could be done cautiously. But the 5 gallon low wines would be fine to run. The 4 gallon low wines will start to produce quicker than the 5 gallon low wines. And the product off the still will have a higher purity than the 5 gallon low wines run.

But in the end, you have the same amount of alcohol to collect, just that the collection will have more water in it when the low wines is diluted.

Does this help?
ss

[DirtyOz]

I’m sorry. I was just throwing out some numbers for comparison. Like how a more dilute solution would compare as far as what the net recovery would be versus a higher abv solution. Also, is one more tolerant of a higher temp when it comes to proof. All this might be a moot point since tail can be re-run anyway. I never really figured out how far into the tail I should take it. I’ve heard talk of congeners (if I spelled that right) being more so in the tails. When tails are added to next spirit run, do they build to an unacceptable level eventually? Just more stuff to figure out.
Yes that does help a lot SS. One day I can help someone new. But I’ll just keep the trap shut for now.

Oz

[Twisted Brick]

It's different when trying to boil mash, because it likes to foam up and/or scorch.

+1

I think this is an important point since even though most don't distill on-the-grain, a lot of us strip with cloudy or particulate-laden AG washes. I have always wondered how much foaming occurs in my strips, and subsequently heat up slowly. (I strip 100% of the wash shown below).

I also remember reading (here) that surface vaporization behaves differently when under pressure versus exposed to the atmosphere. So for grins, I did a stovetop test with a clear lid on a small pot of rolled oats in water. Without the lid, the oat "mash" began to foam into the air with ever-increasing bubbles, eventually overtaking the rim of the pot. With the lid on, the bubbles erupted larger faster, quickly boiling over. At that point it appeared that surface evaporation rate involves more variables than just area.

Gives credence to proper still charge volume, slow heat break, or both.

PS: It would be interesting to repeat the test using an oat mash whose proteins had been altered by fermentation.

[NZChris]

https://www.engineeringtoolbox.com/flui ... d_147.html

The input energy required to change the state from liquid to vapor at constant temperature is called the latent heat of vaporization. When a liquid vaporize at the normal boiling point the temperature of the liquid will not rise beyond the temperature of the boiling point.

The latent heat of vaporization is the amount of heat required to convert a unit mass of a liquid into vapor without a change in temperature.

Note that no allowance for surface area needs to be made in order to calculate the amount of energy required to convert a unit mass of a liquid into vapor.

Alcohol 896 kJ/kg
Water 2256 kJ/kg