New Construction: Improved Hybrid Air- and Water-Cooled Still

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Pierrot Lunaire 55
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New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Pierrot Lunaire 55 »

About a month ago I posted a description of a stripping still that I'd built using a two-stage condenser, first an air-cooled section using a baseboard heating fin equipped pipe, followed by a Liebig condenser.

viewtopic.php?t=87886

I received a variety of comments and decided to make a Mark II version with a number of improvements:
• Additional air-cooling capacity
• More generous pipe diameters
• Replacing the Liebig condenser stage with a shotgun (shell and tube) design
* Convertible between a pot and column configuration

And it would require some basic capabilities:
• Easy to change boilers
• Fits under a relatively low ceiling
• Moveable

Here is the basic concept of the new design: The pipe off the boiler (2 inch) goes straight up about 3 feet, and necks down to 1.5 inch. It turns horizontal and feeds into the first cooling stage. The air-cooling capacity has been doubled by using two fin equipped pipes, side by side, in a shroud box with air forced in by a blower. The box is a parallelogram, 10 degrees off axis, to create tapered sections on each side of the fins.
P1000804.JPG
The photo (one side removed) shows the air inlet in the lower RH corner and the outlet through the three holes. This will stand so the pipes are vertical. The steam inlet and outlet split the flow into both pipes. (I do some ugly solder joints. Sorry.)
P1000806.JPG
This is ready to close up and install on the support structure.

The second part is the shotgun condenser. Thanks to some comments from Twisted Brick, I decided to do a four-tube, 2 inch shell arrangement using the stampings he makes for the ends and internal baffles.

viewtopic.php?f=87&t=67972

Here is the assembly in progress. My adaptation of his design was to make my own inlet/outlet pieces that could be mounted directly on the shell rather than using a pipe tee. I milled a block of brass to match the outside radius of the shell with a through hole for the pipe.
IMG_0841.JPG
Here it is fully assembled. The inlet and outlet pipes are both mounted about 30 degrees off axis so the flow goes between the internal pipes rather than right into the side.
P1000807.JPG
The next phase is the support structure and final assembly. Stay tuned.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Deplorable »

Following along. All those "ugly solder joints" can be cleaned up with a file and some sandpaper if you so choose once the design has proven itself.

Im interested in seeing how much air flow will be sufficient to knock down the vapors.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Pierrot Lunaire 55 »

I'm not expecting that the air-cooled section will be enough by itself, but it should reduce the water flow through the shotgun a lot. I'll try to mount an RTD on the pipe at the bottom of the box between the two stages.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by StillerBoy »

Pierrot Lunaire 55 wrote: Mon Sep 05, 2022 11:19 am I'm not expecting that the air-cooled section will be enough by itself, but it should reduce the water flow through the shotgun a lot.
The shotgun as mounted after the air condenser will only be a distillate cooler.. and how much less water flow is used will be base on power usage and angle of setup..

Since the required efficiency you're after is intended for stripping run, should a puking occur how will the shotty be cleaned..

Mars
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by shadylane »

Pierrot Lunaire 55 wrote: Mon Sep 05, 2022 11:19 am I'm not expecting that the air-cooled section will be enough by itself, but it should reduce the water flow through the shotgun a lot. I'll try to mount an RTD on the pipe at the bottom of the box between the two stages.

I really like your builds. :thumbup:
You might be surprised how much the air-cooled section can knock down.
Just guessing I think it can condense around 4kw but the output is going to be kinda hot.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by shadylane »

StillerBoy wrote: Mon Sep 05, 2022 5:22 pm
Since the required efficiency you're after is intended for stripping run, should a puking occur how will the shotty be cleaned..

Mars
Not only for cleaning a puke, but also for cleaning the black gunk that builds up.
It would have been better if the end of the shotgun had a slip fit instead of being soldiered.
Something like this would let you slip off the end and run a rifle cleaning brush into the tubes.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Twisted Brick »

shadylane wrote: Mon Sep 05, 2022 6:14 pm
Not only for cleaning a puke, but also for cleaning the black gunk that builds up.
It would have been better if the end of the shotgun had a slip fit instead of being soldiered.
Something like this would let you slip off the end and run a rifle cleaning brush into the tubes.
For any member seeking to do this with one of my endplates, it can be done! I recently sent a shotty to a member who specifically asked for a slip fit with the endplate installed flush with the exit end. I placed a flattened solder ring internally prior to inserting the endplate and heated from the outside resulting in no visible solder. Despite heating the shell hot enough to melt the solder inside, the pre-soldered vapor tubes remained perfectly intact (no wet terrycloth inserts needed).
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Pierrot Lunaire 55 »

Puking, in my experience, is closely related to patience, or the lack thereof. If I have the heat turned up high and leave it that way right as the mash comes to a boil, about half of what's in the boiler will come blurping out of the condenser. At least it seems that way. If I watch carefully and back off the heat as it approaches the boiling point, I can usually keep it under control.

Nonetheless, if this proves to be a problem, I may have to resort to removing the end cones. Something I don't really want to think about. Actually, I set the end plates of the condenser back inside the shell a bit so I can probably saw it off if nothing else.

As I work on the fully assembly of the system, one other potential problem could emerge. I know it's coming, we'll just have to see how bad it is. Stay tuned.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by StillerBoy »

Twisted Brick wrote: Tue Sep 06, 2022 9:54 am Despite heating the shell hot enough to melt the solder inside, the pre-soldered vapor tubes remained perfectly intact (no wet terrycloth inserts needed).
Ahh.. nice to read about the wisdom of experience in soldering..

Unlike reading about cutting off instead, as any part can be un-soldered and re-soldered without impacting other parts..

Mars
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Pierrot Lunaire 55 »

Yesterday I did a full assembly with all the pipe connections and support structure. Most of the structure is still a bit bodged together as you'll see in the photos. For proof-of-concept, it doesn't have to be pretty. Here 'tis:
P1000809.JPG
(As usual, pardon the cluttered background.) As you can see, the main support is basically a table holding the cooling shroud and blower, plus providing pipe support. The boiler has a 2 inch column with two tri-clamps holding a 32 inch removable center section. This is simply an open pipe, but my plan is to create a packed column with a deflegmator that can be put in the same place for spirit runs. Here's a better look at the steam side. As you can see, it necks down to 1.5 inch below the elbow and then into a pair of .75 inch pipes for the actual finned coolers. There is a thermowell inserted through the elbow extending several inches into the horizontal pipe for reading the temperature by inserting an RTD.
P1000811.JPG
On the blower side, the blower forces air into the shroud, passing through the finned pipes and exiting through the round holes. This is a small version of the type of blowers contractors use to dry floors and cure drywall mud, available at fine big-box stores everywhere. The air connection is ugly but it works. At the bottom, you can see where the two cooling pipes are joined, and sent to the shotgun condenser. Note that there is an RTD attached to the pipe and wrapped in insulation. This provides a rough reading for the steam/condensate at the end of the air-cooled stage.
P1000816.JPG
The shotgun condenser extends to the right. I'm trying to decide if I want to attach everything to a common base. Jury's still out on that, although I will certainly make a better outboard support for the shotgun.

Yesterday I was flushing the piping by pumping water through the outlet to clear remaining solder flux, etc. Today I put a few gallons of water in the boiler and did a full run.

So, does it work?

(First, I forgot to use the shroud around the boiler, so that was my mistake. So all the measurements relate to running without the shroud.) Once things heated up, I put the blower on HIGH and turned on a trickle of tap water to the shotgun.

Temperature at the top of the column ran rock-steady at 210 F. Temperature at the bottom of the air cooler was barely warm, but gradually crept up and stabilized between 128-135 F. It fluctuated within that range, but I don't know why. Air blowing out the top of the shroud stabilized at about 130 F. (I want to have this to heat my house over the winter. It puts out a lot of hot air. Before long the temperature in my garage was about 90 F.)

The boiler was running at about 12 minutes per quart (13 minutes per liter) so you get some idea about how hard it was working. With just a trickle of water into the shotgun, the distillate was cool as can be.

Technically, it's a success in my thinking. The question remains, is it a very elaborate solution for a minor problem? That being trying to save cooling water? I like it, if nothing else, so why not? I have one more stripping run to do for the season, so it will get its first actual test in short order, as soon as the jugs stop bubbling.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by shadylane »

Pierrot Lunaire 55 wrote: Thu Sep 08, 2022 11:28 am

Temperature at the top of the column ran rock-steady at 210 F. Temperature at the bottom of the air cooler was barely warm, but gradually crept up and stabilized between 128-135 F. It fluctuated within that range, but I don't know why. Air blowing out the top of the shroud stabilized at about 130 F. (I want to have this to heat my house over the winter. It puts out a lot of hot air. Before long the temperature in my garage was about 90 F.)
I'm guessing with cold weather and some alcohol in the boiler the shot gun won't be needed. :ewink:
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Pierrot Lunaire 55 »

So I did an actual stripping run this morning, about 25 gallons of mash divided into three batches. Probably about 9% ABV. Each started boiling around 197 F and I pushed over about 5 liters with each batch. They did not all behave the same. They started out similarly, gradually building up heat in the air-cooled section. Each developed a temperature at the output of the air cooler of at least 140 F, but one went up to 157 F. I don't know why because they were all running at similar rates. Apparently there was more difference than I realized. Using cold tap water for the shotgun, I was able to run with just a trickle of 5 to 6 gallons per hour. (With the original hybrid unit, I would use at least 20 gallons per hour.)

The thing that puzzles me is with the shotgun. When using a Liebig, I got used to the idea that the distillate can be warm, probably 110 F or more, even when the condenser seems fairly cold. I did not expect that with the shotgun, but as I neared the end of all three runs, I was getting bathwater temperature distillate out of the condenser, even with a cold condenser. Is it possible that when the condenser is about 30 degrees off horizontal that most of the liquid is passing through just the bottom pipe of the four inside? Are the upper three simply empty much of the time?

Interesting.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by StillerBoy »

Pierrot Lunaire 55 wrote: Sat Sep 10, 2022 1:39 pm but as I neared the end of all three runs, I was getting bathwater temperature distillate out of the condenser, even with a cold condenser. Is it possible that when the condenser is about 30 degrees off horizontal that most of the liquid is passing through just the bottom pipe of the four inside? Are the upper three simply empty much of the time?
What was the cooling efficiency of your air condensers at that point.. the shotty required more water flow due to the higher temp reaching it.. and 30 degrees does not help as a shotty should be vertical for best efficiency..

Mars
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Pierrot Lunaire 55 »

I suspect I'm using a shotgun under the worst conditions. A sloped horizontal installation is probably OK if there is only steam entering, but liquid will tend to run to the bottom pipe. I'm probably getting a mix of both if the temperature at the shotgun inlet is 130 to 150 F.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by shadylane »

Sounds logical to me.
The shotgun is good as at knocking down vapor.
But as a liquid chiller, the lowest tube gets all the liquid.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

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Pierrot Lunaire 55 wrote: Sat Sep 10, 2022 2:42 pm I suspect I'm using a shotgun under the worst conditions. A sloped horizontal installation is probably OK if there is only steam entering, but liquid will tend to run to the bottom pipe.
All the tubes are getting all equal vapors, but what happening in a horizontal install is that the distillate is only run along a very small portion of each tube to the overall available cooling.. whereas in a vertical install all the tubing wall is available..

Mars
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Yummyrum »

StillerBoy wrote: Sat Sep 10, 2022 6:06 pm
Pierrot Lunaire 55 wrote: Sat Sep 10, 2022 2:42 pm I suspect I'm using a shotgun under the worst conditions. A sloped horizontal installation is probably OK if there is only steam entering, but liquid will tend to run to the bottom pipe.
All the tubes are getting all equal vapors, but what happening in a horizontal install is that the distillate is only run along a very small portion of each tube to the overall available cooling.. whereas in a vertical install all the tubing wall is available..

Mars
You are correct Mars , but in this case , the air condenser has condensed most of the vapour to liquid before it reaches the shotty and so it will concentrate on the lowest pipes.

Pierrot , is it possible to rotate shotty so there are two pipes at the bottom . May help a bit maybe . But yeah , not the best condenser for the job at hand
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by Pierrot Lunaire 55 »

I've made some additions to this project so I can run it with a defleg and packed column for spirit runs. That has been an adventure in itself. I am going to start a new thread soon in the column builds section to explore methods for controlling a defleg. Stay tuned.
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Re: New Construction: Improved Hybrid Air- and Water-Cooled Still

Post by LWTCS »

shadylane wrote: Sat Sep 10, 2022 2:57 pm Sounds logical to me.
The shotgun is good as at knocking down vapor.
But as a liquid chiller, the lowest tube gets all the liquid.

Yep.
Best ( for liquid to liquid HX) to use the shell for distillate and the inner tubes for cooling media. Then only employ a slight pitch to optimize dwell time. So,,,mostly a horizontal orientation.
This also allows the accumulation of liquid distillate in the shell to assist as an additional heat sink.
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