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In this Discussion
- CothermanDistilling October 2015
- dwhuff October 2015
- grim October 2015
- jacksonbrown October 2015
- jbierling October 2015
- Kill_Devil_Spirit_Co October 2015
- Myles October 2015
- punkin October 2015
- Ryno October 2015
- SDeurope October 2015
- Smaug October 2015
- TheMechWarrior October 2015
Comments
that is why I gave the link so you could punch in your numbers...
I appreciate it. It appears to be accurate.
Ok, I really don't have time for this but I will clarify my previous comments. I have a 200 gallon pot. Its not a stilldragon pot. I don't put a 200 gallon charge in it. It ends up being 160 to 170 gallons. I thought that would be understood but I should have made it clear. I know when we talk about size its usually in terms of charge volume. My washes are 8.5% to 9.5% typically. Its usually 75 to 80 degrees in the distillery so the wash will be in that range also. I have a stilldragon pot and column and used it for 2 years. I have a larger system now but when I upgrade again I'll go back to stilldragon for the equipment. The still I'm using now was custom made for me to maximize the power and space I had available. Heat up time to 4 plates bubbling is 1.5 hours. Agitator running from the start. Use whatever calculator you like to disprove. I just finished a run this afternoon. 1.5 hour heat up time.
Real world trumps theory once again.
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The rate the heat can flow through the jacket will be higher with a greater the temp difference, that's one benefit to high temp oil jackets.
That's also why the mixing is making a difference but I'm still getting my head around it as the same power is going into the elements regardless. Is it from higher heat loss rates? Have to let it stew a bit more :-?
Thanks for chiming Dave.
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Hey guys, Im the customer Punkin started this post for. Thank you so much for taking the time to help.
After reading all your comments, im thinking of doing a water jacket style. To make the water jacket 100% safe, would it not be best for the water jacket to have an open 'chimney" style port so that it cannot build up pressure, thus eliminating the chance of an explosion?
The first negetive with this idea that comes to mind is the amount of water steam you would loose during the entire run so the water level would drop inside the water jacket. But would it only start to steam once the temp gets up around 80 degrees Celsius which by that time the run is mostly done so the loss of water would not be anything too large? Or have I got it wrong and the water jacket actually needs to be hotter than 100degrees for the wash to get to the 80degree temperature? Is there a flaw to my thinking?
Thanks again for your time and effort with this topic guys.
The boiler will be shipped with 15psi relief valve as well.
StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand
Hi Ryno, you're close with your desire for a chimney. My understanding is an expansion chamber would be used. Perhaps someone more knowledgeable will chime in.
Don't forget you need a temperature differential/Delta T/driving force for heating. So you are going to want close to 100 in your jacket while you are heating up and then back it off somewhat prior to hitting a boil. I have no idea what temps you'll need in your jacket to give you a boil but there's no shortage of operators here who would know.
At 10kw of power input, full boil, you can expect to boil off 15.86 liters per hour of water from the jacket.
36,000kJ/hr / 2,270kJ/kg = 15.86kg/hr
This is only on the boil side and doesn't reflex the heat transfer taking place, which means 15.86l is a worst case theoretical.
I think my math is correct. :)
While the expansion tank would be useful in an oil situation (since it would allow you to seal the jacket, in the water scenario the expansion during boiling would quickly consume the volume of the expansion tank, if you were sealed, if you were open to the atmosphere, the expansion tank wouldn't do anything at all.
A good way to look at water as an HX is to look at the boiling point in a different way.
In most cases, the boiling point of water is a good thing.
However, in the case of HX (without steam as the medium), the boiling point of water is a road block, a problem, and it just so happens that the road block is in the wrong place too.
Once the HX starts boiling, now we have a problem, we either need to deal with the resultant spike in pressure, or we need to reduce the HX temperature (which means significantly less power input), or, we let it boil off.
The liquid loss is only half the problem with boiling off, the other is the huge loss in power efficiency by losing the steam to the atmosphere.
You might think, I'm just going to add some glycol to the jacket, but now you are just going to foul your glycol with minerals if you lose the water to steam. You can keep adding water to make up for the volume loss, by you'll eventually turn your hx to muck and coat your kettle in scale and kill your elements, so no dice there.
And, I mean, if you are really looking to get creative.
Put a 5psi pressure relief on the kettle jacket, fill it with a 50% glycol mixture (leave headspace for expansion, otherwise use an expansion tank set correctly), and run the jacket with a temperature limit controller to keep the liquid temperature from going above 240 degrees.
What you are doing is moving the roadblock up the road, to give you more headroom.
You don't ever let the HX hit boiling point, however you will be building pressure.
But now you are introducing all sorts of complexity.
Water only becomes a problem at boil, can't water do a good enough job below boiling point?
Thermal gradient. I have run 100% glycol at 130 degC before now and it wasn't anywhere close to boiling. The only issue is that without ph buffers it can start to degrade when it gets too hot.
Steam gives you the increased thermal gradient. Pressurised steam, an even bigger gradient. Have you ever tried putting a can of water inside a pot of boiling water and seeing how long it takes the can to boil. Be prepared for a long wait.
A 5% wash is boiling at 205f, a 10% wash is boiling at 199f.
Assuming you can hold the jacket at 211f, you are talking about a delta-t of 6-12f for typical scenarios, and that is at the start, through the run this will only drop lower. This is what I mean by road block, the phase change temps of the HX and the liquid are so close, that if you can't boil the HX, you have to pull back your power input to compensate.
And, when you do that, remember, as delta-t decreases, your efficiency of heat transfer decreases as well.
Also, with steam, don't look at the temperature of steam at pressure, that is misleading. The phase change of condensation transfers a massive amount of energy compared to the temperature of the condensate.
Filling the jacket with 250F water is not the same as steam at 15 psig (250f), not by a long shot. The steam condensing will transfer more than 4 times the energy to the jacket walls than the water will, and it will do it with significantly more efficiency.
With our BM, it is only the liquid reservoir that gets filled. The remaining head space that is within the jacket is for steam/vapor heating. The vapor must occupy that space in order to generate enough oomph to liberate the alcohol.
If the entire jacket is filled with water, the dern thing would take hours upon hours to heat up.
And as Grim mentions, you will absolutely struggle to render alcohol through out the run,,,particularly toward the middle/end of the run.
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a 10' pipe/stack filled with water above the jacket gives your 5psi without the need for a valve...
Diameter matter on that?
StillDragon North America - Your StillDragon® Distributor for North America
About 5 feet should do it
No diameter bears no affect on head pressure.
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I'm keen to know what temperatures people are running BM jackets at present and for what products. And what sort of boil up and run times they experience.
Smaug your comment above is important. I was not aware of what you described until I looked at some of the prints again.
@TheMechWarrior, my buddy is running the 100gal BM with peanut oil up to the sight glass. This gives him boil up of ~90-100 gal of on grain whiskey at ~7-8% in about 2 hours. He starts with 22K and agitator then switches to 22k plus an adjustable 5k for dialing in output. He isn't measuring jacket temp so can't tell you
Another guy is using the heat circuit and pumping water around. He has the ability to hold temp so dials in as needed as far as I know. That's all the info I can give on that one.
When the guys I'm working for right now get their still in I will be recording damn near everything and posting it all here. I will be experimenting with both water and oil, though water sounds like the better option when it comes to heat up time and controlling output.
Diameter won’t make a difference to static head but it will play a part in dynamic head.
Total pressure head is static plus dynamic.
Less restriction = less back pressure.
I don’t think all that effects the jacket conditions much though.
I think there are too many variables in it for anecdotal evidence to be of much use here, unless you have all the details at your disposal.
Personally, I’m leaning towards pressurised water or oil BM and controlling the detaT between the jacket temp and wash temp.
It’s that difference in temp that is going to govern the boil in the wash.
Here’s the results from some ambient steam jacket testing I did a few years back.
It was just a double boiler on the stove. One temp is the ‘jacket’ and the other is the boiler.
At the time I was thinking about using an external boiler pushing ambient pressure steam into my boiler jacket as a low cost, ‘safe’ steam jacket system.
I ended up dropping the idea as you can see I hit a wall at about 91°.
Any more power in the element at that point and was only boiling off the jacket contents quicker. I couldn’t get the contents of the boiler any hotter than 91°.
There is only so much heat I could get through the wall of the jacket and at 91° the heat loss was the same amount.
insulation etc. could help out but you can see the issue.
This is why I’m dubious about non pressurised water jackets.
At the end of the run the detaT is approaching zero. Zero delta T means zero heat transfer.
You can put in as many Watts as you like into those elements but you’ll be boiling the jacket, not the wash.
I don't think you need to boil off any water.
The water is just a contact medium for conducting heat. If your jacket is boiling you're not doing it right IMO.
It depends. If you can get the water to a sufficiently high temp in a closed system then I suppose it might not need to boil.
Boiling point of water at 30 psi or 2.07 bar is 121°C. However the huge energy advantage comes from condensation of steam back into water on the surface of the inner pot. You would need to do the energy calculation to show it, but the steam is far more efficient than the hot water.
The big advantage of the glycol is that you can attain the same temperature 121°C at atmospheric pressure and well below the boiling point of the glycol which is 188°C.
These are old now but they do indicate the principle of a glycol bain marie pot still boiler.
glycol temp vs wash temperatore in an insulated boiler with the power switched off when the glycol reached 120°C
The same glycol pot still as above showing glycol temp vs vapour temperature in the pot still headspace.
The big advantage of the HX fluid like glycol or other oils, is that you don`t need to use a pressurised jacket to get to the same temperatures.
The bigger the temp difference between your bath and the wash, the more energy you pump into the wash. Do bear in mind though that it is just as easy to burn a wash or mash with an over hot jacket, as it is with direct heating. If the inner surface of the boiler gets hot enough the contents will burn - it doesn`t matter what the heat source is. All that matters is how well that heat is dissipated into the boiler contents.
Re:Agitator and reduced heat up time
As the jacket heats, the liquid closer to the inner surface heats up faster than the liquid further away, this hotter liquid near the jacket wall forms a kind of insulator (reduced delta-t, lower heat transfer), until there is sufficient convective mixing to reduce the temperature.
An agitator can force the liquid away from the walls, resulting in less stratification of the water, and ensures that delta-t is kept at a maximum. Increased efficiency, reduced heat up time, etc etc.
I was talking about open systems. In an open water bath it doesn't matter how much steam you have spewing out of the jacket if the contents are low ABV (high BP), it's the delta T through the wall that transmits the heat. You're just wasting energy on latent heat that isn't doing anything for you.
Best to keep the max jacket temp a few points under it's BP. If the wash is close to 100° the steam just won't condense no matter how much you blast at it.
Pressurise the steam to get it over 100° and you get that delta T back and you're in business.
That's spot on Grim but where is that extra 0.5 hour of energy going if you don't turn on the agitator???
On heatup, my boiler will not cycle, it will run until we hit operating temps and then begin to cycle as expected. Despite being 15hp, I can't get my boiler to full pressure with cold still contents. The steam condenses nearly as fast as I can push it.
The most enlightening situation, is when we were building pressure in the jacket, but the agitator was off. As soon as I flipped the agitator on, the jacket pressure dropped pretty significantly. Meaning the lower jacket temp collapsed the vapor in the jacket, and the boiler could no longer keep up with the condensation again.
Lower delta-t, less condensation, increased jacket pressure. It's that the energy wasn't going where it should have been going fast enough.
Feed me Seymore!
You'd think that the higher jacket pressure means more energy is being transferred, but it sure didn't work out that way. Maybe if I had one of those fancy Fultons, I could push more volume. But really, 15hp is 15hp.
Another thing is, you would think all the pressure gauges would read the same.
Nope. Midway through heatup, my boiler pressure gauge is reading 11-12 psi, and the jacket reads about 5 psi.
Another way to look at it, the 1000 liter steam jacket can easily consume 150kw (less efficiency losses) of energy without a batting an eye.