yet another new build query

[dingfelder]

Hi all

I acquired a still that was being used for making vodka and I've been adding improvements over time and am keen for some feedback on how to make it better.

what I started with is:

original still pic

• digiboil 65L boiler
• 15amp voltage regulator
• 2" to 3" reducer (reversed)
• two 3" columns - insulated - about 600mm high total
• 3" reflux condenser
• 3" to 2" reducer with thermometer gauge
• two 2" 90 elbows
• 2" shotgun condenser
• 2" (swan neck? liebig?) condenser
• 2" vented output
• also water reservoir and pump for coolant lines, and 65L fermentation tank

I am running the still in 2 modes, pot still or reflux but my questions here are mainly surrounding the pot still mode
I purchased several new parts:

• new upgraded digiboil lid with 4" hole and lid sightglass
• 4" to 3" reducer
• 3" sightglass wiih filter
• 2" sightglass with filter (gin basket)

so now, running in pot still mode i have:

current still pic

• digiboil 65L boiler
• 15amp voltage regulator
• new upgraded digiboil lid with 4" hole and lid sightglass
• 4" to 3" reducer
• 3" sightglass with filter
• two 3" columns - insulated - about 600mm high total
• 3" to 2" reducer with thermometer gauge
• two 2" 90 elbows
• 2" shotgun condenser
• 2" (swan neck? liebig?) condenser

also invested in:

• still spirits filter pro
• heavy duty hoses with camlocks and magnetic pump
• got an air still for experimentation
• 2" stainless steel distilling parrot with 2" tri-clamp - would like to use for stripping runs to know when to stop

Questions I have:

1. one thing i'm not at all happy with is how to get product from the 2" (swan neck? liebig?) condenser, which has a 1/2" hose barb fitting for the output - its not in a place where I can easily capture the output, so I have to use silicone tubing which I don't want to do
   for reference the condenser im mentioning above is:

   

   condenser.jpg (8.33 KiB) Viewed 1199 times

2. related to the previous question, when i'm doing a stripping run I would like to add my parrot to the end of the stack, but the output of the condenser being a hose barb is not good as there is no way I can think of to go from a barb to a 2" tri-clamp - is there any sort of attachment I can use to do that?
3. when I am heating the boiler I crank it up to 3500 watts. Then when doing a spirit run, I lower the wattage so the output is a small stream. If I'm doing a stripping run though, I want to run faster... but I was running into issues with the output temperature being too high when I just used one condenser, so I added a second condenser which you can see in the 2nd pic above. if I up the wattage though, the run then does a lot of "huffing". Ive read that this can be caused by vapour locking, if the temp cools too quick? I'm wondering it I can eliminate that by changing the angle of the condensers - what is the optimum angle to allow me to run faster but still cool all the vapour?

[dingfelder]

in case you wonder here is a pic of the parrot I purchased

parrot

parrot.JPG (8.14 KiB) Viewed 1195 times

and I have purchased another elbow that I can use in between the 2 condensers, that im hoping will tell me the vapour temp

I also have ordered this basket that I hope will help me in making full grain mash

basket.JPG (12.48 KiB) Viewed 1195 times

[Salt Must Flow]

So your shotgun condenser won't knock down 3500W? How many tubes are inside it? I'm guessing 4 or less? What is the length of your shotgun? My 2"x24" shotgun condenser will knock down 11000W though it is made of copper and has seven 3/8" copper tubes. I know there's stainless shotgun condensers that have 7 stainless tubes and I've even seen some that have 7 copper tubes which would be ideal. You really shouldn't need more than a single shotgun condenser for any use.

Are you sending water down the drain or are you recirculating water? The reason I ask is because I use cold tap water and send it down the drain. For my shotgun condenser to handle 11000W, I need to increase the water flow. When I'm doing a spirit run, it barely needs a trickle of water. If you're recirculating water then how many gallons is the reservoir?

I don't know what that hose is made of that's connected to the product outlet of that condenser, but I'd get rid of it.

If there's "huffing", I imagine that is coming from the Liebig condenser. Reducing flow to the condenser stops that. There's a video demonstrating this on this page.

[dingfelder]

Thanks for the responses

So your shotgun condenser won't knock down 3500W? How many tubes are inside it? I'm guessing 4 or less?

I think its 5 tubes but I need to confirm

What is the length of your shotgun?

I think its about 500mm but ill confirm

My 2"x24" shotgun condenser will knock down 11000W though it is made of copper and has seven 3/8" copper tubes. I know there's stainless shotgun condensers that have 7 stainless tubes and I've even seen some that have 7 copper tubes which would be ideal. You really shouldn't need more than a single shotgun condenser for any use.

my 3" (reflux) condenser has 6 holes and is about 200mm

Are you sending water down the drain or are you recirculating water? The reason I ask is because for my shotgun condenser to handle 11000W, I need to increase the water flow. When I'm doing a spirit run, it barely needs a trickle of water.

I would like to switch to 2 tanks that i could alternate between but for the moment I'm sending down the drain
When im doing a spirit run I agree that flow is probably not an issue, its for stripping runs that I cant keep up and need 2 condensers I think. may have to do some more testing once I add a thermometer after the 1st condenser

I don't know what that hose is made of that's connected to the product outlet of that condenser, but I'd get rid of it.

its 19mm silicone. Thats my first question - what would you use instead?

If there's "huffing", I imagine that is coming from the Liebig condenser. Reducing flow to the condenser stops that.

I will give that a go -and/or may add some scrubby material to the end which I heard can help

[Yummyrum]

I’m surprised that the Shotty won’t knock down 3.5kw as well SMF .
Ideally , Shottys should be run vertical for max efficiency .
I’d be supprised if that little liebig would help at all .

If you had another 2-3” adaptor , you could run into the 3” Shotty first ( what you were using as a Degleg) and then into the 2”shotty . Then you could keep them all vertical and use your parrot . That will also fix the plastic on the output .

EDIT : regarding the huffing . It isn’t a problem as such , just messy and noisy . As you’ll see in that video that SMF linked to that I made , the huffing can be significantly reduced by simply turning down the coolant flow to the condenser . Huffing can also occur on a Shotty , butbit is not as common as it is on a Liebig .

[Salt Must Flow]

I would like to switch to 2 tanks that i could alternate between but for the moment I'm sending down the drain
When im doing a spirit run I agree that flow is probably not an issue, its for stripping runs that I cant keep up and need 2 condensers I think. may have to do some more testing once I add a thermometer after the 1st condenser

During a stripping run, that thermometer is not of any significant value. It will NOT tell you anything that has anything to do with your product condensers. All that thermometer will tell you is the vapor temp before it enters the product condenser. If your product condensers cannot handle the power input during a stripping run, you MUST either reduce the power input, increase water flow or lower the temperature of your water. Lowering the temperature of your water can be done multiple ways. You can run water directly from your tap (which should be a continuous cold temp). You can recirculate water from a larger reservoir. You can use a radiator & fan to draw heat from the condenser's return water. There's other ways too, but I'm just sticking to basics.

Now during a spirit run that thermometer might be of some value. If that still is being operated properly, during hearts the vapor temp should maintain steady within a few 1/10th degree the whole way. ONLY once tails arrive will the temp rise. That's a signal to shut down.

If you're using too small of a water reservoir then your water will get too warm/hot and your product will exit warmer. You said, "output temperature being too high". Do you mean the exiting product or the water exiting your product condenser is too high? You later said that your Liebig was huffing which typically means that the water flow is too high and/or the water is cold (causing the vapor to collapse therefore huffing). This makes me a bit confused. If you water is too hot then your Liebig should not be huffing. If your product is exiting too warm/hot then that should mean that your water is too warm. If your water is too warm then the Liebig shouldn't be huffing. I'm confused.

[Yummyrum]

I’m confused too .
If you have enough flow of cold water , why can’t the shotty cope on it’s own ?

By any chance do you have the water lines back to front ?
Water should enter the condenser at the end where the product comes out . IE , it is usually the lower end of then product condenser .

[dingfelder]

So your shotgun condenser won't knock down 3500W? How many tubes are inside it? I'm guessing 4 or less?

confirmed 5 tubes

What is the length of your shotgun?

confirmed - 450mm

---

I’m surprised that the Shotty won’t knock down 3.5kw as well SMF .
Ideally , Shottys should be run vertical for max efficiency .
I’d be supprised if that little liebig would help at all .

I was (mistakenly?) assuming that having the shotgun condenser vertical would make the product travel through it quicker, so it would cool less as it has less time to make contact with the cooler temps. If it definitely works better vertically, why do pot stills seem to be angled?

---

During a stripping run, that thermometer is not of any significant value. It will NOT tell you anything that has anything to do with your product condensers. All that thermometer will tell you is the vapor temp before it enters the product condenser. If your product condensers cannot handle the power input during a stripping run, you MUST either reduce the power input, increase water flow or lower the temperature of your water. Lowering the temperature of your water can be done multiple ways. You can run water directly from your tap (which should be a continuous cold temp). You can recirculate water from a larger reservoir. You can use a radiator & fan to draw heat from the condenser's return water. There's other ways too, but I'm just sticking to basics.

I dont really look at the top thermometer much
I was hoping that having a thermometer after the condenser would help me confirm that the product was getting fully condensed to 20ish as I want to ensure no vapour is getting past

Now during a spirit run that thermometer might be of some value. If that still is being operated properly, during hearts the vapor temp should maintain steady within a few 1/10th degree the whole way. ONLY once tails arrive will the temp rise. That's a signal to shut down.

If you're using too small of a water reservoir then your water will get too warm/hot and your product will exit warmer.

My "reservoir" is just a 20L tank to buffer flow from the incoming hose, to ensure water cooling isn't interrupted, its temp is the same as the incoming water

You said, "output temperature being too high". Do you mean the exiting product or the water exiting your product condenser is too high?

Yes I meant the spirit/product output was warmer than 20C, so I wanted to make sure it was colder, I was thinking I could smell output vapour if it was running too fast

You later said that your Liebig was huffing which typically means that the water flow is too high and/or the water is cold (causing the vapor to collapse therefore huffing). This makes me a bit confused. If you water is too hot then your Liebig should not be huffing. If your product is exiting too warm/hot then that should mean that your water is too warm. If your water is too warm then the Liebig shouldn't be huffing. I'm confused.

when I said the output was too warm that was when I had only one condenser (shotgun)
when I added the 2nd condenser I have not had any issues with it being too hot. but im not positive what the temp is between the 2 condensers, thats why ordered another thermometer so I could watch that

[dingfelder]

By any chance do you have the water lines back to front ?
Water should enter the condenser at the end where the product comes out . IE , it is usually the lower end of then product condenser .

water is definitely flowing in at the bottom and out at the top
water flow is I think about 2-3L/min via 12mm ID tubes

[dingfelder]

I will try again with the one shotgun condenser vertically (at max water flow) and see what happens

[Yummyrum]

I’ve been watching these forums for about 10 years now . In nearly every shot gun PC , it is vertical . It is however very common to see nearly every Liebig on an angle .

Only time I see Shotty in an angle is if the guy has to angle it to get the end high enough for collection jar .

If you imagine the water in the shotty is level with the height of the top coolant line , you can see that the top pipes in the shotty are not working as well as they could .

If you angled the shotty so that the pipes go up rather than down , that would help , but then you have to deal with hose supports etc . Just easier to hang the Shotty vertical .

IMG_9425.jpeg (25.05 KiB) Viewed 1132 times

EDIT: it doesn’t matter if your distillate is warm .If you can hold your hand under it then it is usually cool enough .
So yeah , run the PC vertical with water flat chat . If you can hold your hand under the distillate , then try slowly reducing water flow until it starts to either get so hot you see vapour coming out end . Then you know your minimum coolant flow , increase it a bit for safety .

If at water flat chat , you see vapour , then you need to turn power down .

[greggn]

so now, running in pot still mode i have:

[*]15amp voltage regulator

How are you managing to control power to the boiler ? A voltage regulator is not the same as a power controller (which regulates amperage). My guess is that you're effectively running full power.

[still_stirrin]

This question gets asked frequently, but I think the engineering behind the answer is often misunderstood:

I was (mistakenly?) assuming that having the shotgun condenser vertical would make the product travel through it quicker, so it would cool less as it has less time to make contact with the cooler temps. If it definitely works better vertically, why do pot stills seem to be angled?

Gravity. It’s not just a “good idea” … it’s “the LAW”.

But seriously, shotguns work best in the vertical orientation so the condensate will wick down the vapor tube walls and drip from the condenser quicker. Gravity helps pull the condensate out of the spout.

Liebig condensers would similarly work better if the condensate was removed from the vapor tube walls faster so that the hot vapors could be exposed to the tube walls for condensing. Remember, the tube walls are where the heat transfer must pass in order to condense the vapors.

But why shotguns vs Liebigs for vertical orientation? It gets to their designs.

There are 2 “areas” that are fundamental to their design:

1) The vapor flow area, that is —> pi x ID x ID / 4, times the number of vapor tubes (N) in the tube bank.

This affects the vapor flow velocity for a given mass flowrate (which is determined by the heat input and wash composition). Ideally, the flow velocity should be less than 20 feet per second in order to efficiently transfer the vapor’s heat to the condenser (vapor tube) walls. Velocity is directly related to the “dwell time”, that is, the time the vapors (can) contact the condensing surface before it gives up its heat and condenses. Undoubtedly you’ve heard of this term (dwell) before.

2) The vapor tube surface area, that is —> pi x ID x L (where L = vapor tube length), again times the number of tubes in the tube bank (N).

This is the area through which heat is transferred and onto which the vapors will condense. A greater condensing surface area will provide more heat transfer capability, as in a greater mass transfer/flowrate, or even a greater temperature differential between the vapor inlet and the condensate outlet. Again, dwell time for the vapors to contact the condensing surface areas affect the efficiency of heat transfer (knockdown power).

Now about orientation:

Shotguns typically have greater vapor tube surface area for a given length provided the vapor flow areas are approximately equivalent. As a result, they can be much shorter and therefore can be oriented vertically in order to let the liquid condensate drip from the condenser quickly, and that in turn re-exposes the tube wall to incoming hot vapors.

With a Liebig, since the condensing surface is less efficient, the vapor tube is positioned less vertical (almost horizontal) in order to improve dwell time. Also, Liebig condensers will be made longer in order to provide enough surface area to transfer the vapor’s heat.

An advantage of a longer condenser is that the temperature gradient between the vapor inlet and the condensate outlet is/can be longer and more gradual, and this helps reduce the likelihood of “shock cooling” or “huffing” within the condenser.

If vapor velocities are fast (high boiler input heat), then the tube diameter must be larger (to accommodate the mass throughput), which will increase the surface area. But looking at the equations, the flow area is a function of the tube diameter squared and the surface area is only a function of the tube diameter and the tube length.

So, geometry (physical condenser length) does affect orientation in terms of heat transfer efficiency as well as ergonomically, as in, where you can place the condensate collection vessel relative to the boiler.

Long Liebigs typically require a slanted, or close to horizontal, orientation to get the spout away from the boiler. The much shorter shotguns can be oriented vertically, which assists performance, although you still need to keep the spout (outlet) away from the boiler, especially if it is heated with flames.

I’ve opined exhaustively about orientation of condensers here and I don’t know if I’ve actually answer the original question adequately. But I don’t want to drone on and on …. and on … and on…
ss