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Condenser Design/Size/Build Question


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Hedgebird.

If you do not have a baffle in the top of your condenser then your vapor is only going through a few of your tubes (the ones that are directly below your line arm input). If there is no baffle then the vapor will not spread horizontally outside the diameter of the line arm input pipe. If you don't have a baffle then take the top off of your condenser and lay a piece of perforated stainless plate cut a little smaller than the ID of your condenser on top of the tubes. This will spread the vapor out evenly and it will go down all of your tubes instead of just those within the diameter of your line arm input. The plate should have 3/32" holes on 5/32" centers. I can sell you a piece cut to your dimensions. Call 417-778-6908 ask for Paul. Another option is to pack some 304 stainless steel scrubbers (make sure they are 100% stainless) in there or some copper structured packing material or copper scrubbers. If you use scrubbers, you will have to clean them from time to time. I would be glad to sell you a couple of copper tri-clamp ferrules and a tri clamp so that you can weld the ferrules to the condenser shell so that you can take the condenser apart and put it back together at the top for cleaning. The perf plate is the best way to go. Try baffling the top before you try anything else, because it can save you allot of money over building a new condenser. If you already have a baffle in the top of your condenser then this is not the problem.

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Here is my 2 cents.

Look at it this way, you don't need a bigger condenser, you need MORE condenser (even thought its kinda the same thing). It looks like you have several feet above your current one before it gets to the elbow. Let just say for conversation it is 3' long, I'd build a 3' x 8" condenser and raise your current one up to the top by the elbow and put the newly made condenser underneath (or switch them). Next I would hook them together in series.

**It would save on the building cost.

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HedgeBird, are there no baffles at all in your current condenser to make the water flow more turbulent?

Correct. My current condenser has no baffles on the shell/water side, and no baffle/spreader at the top of the tubes on the vapor side. It would be possible for me to cut open the top to add a baffle/spreader as Paul suggests, but near impossible at this point to add baffles on the shell because of the way I built this.

There are additional reasons why I want to build a new condenser and not try to fix/improve this as Paul suggests, or add to it as Dehner suggests.

- Current condenser seems to have a small leak between the tube and shell.

- Would prefer all stainless and not copper at this point. (my distillate seems to pull a lot of copper salts and I think this is because of the combination of these two factors)

- Not enough cooling power (as stated)

- I have not done a real metal project since I finished building the still and would enjoy the project

So assuming I am building a new condenser, do you guys agree that a 8' x 6" (vapor on the shell side/water on the tube side) with seven baffles (about 1 every foot) would be plenty big enough for anything I could throw at it with my 320,000 BTU boiler?

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HedgeBird,

8' x 6" should be good enough but I would be inclined to go 8" x 7' if you really want to handle anything that you can throw at it with 320,000 BTU output boiler. You could do a stripping run in less than 2 hrs if you wanted to do it with the 8"x7' with the baffle spacing every 12" or so. I have 6", 8" and 10" stainless tubing in stock. It is mirror polished and we can engine mill it for you if you like. I don't have any 3/4" tubing, but I have some 1" stainless tubing that is 7/8" ID. I also have plate and sheet in 304 and a very good selection of tri clamp fittings and parts. I buy in bulk from the manufacturer so my prices are really good even with shipping. paul@distillery-equipment.com http://distillery-equipment.com

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O.k. let's go...this article should get it going. If not, I have other research papers on EC.

Whiskey Science ...Saturday, October 18, 2014
Copper Product Condensers

http://whiskyscience.blogspot.com/

"Ethyl carbamate (EC, urethane) was a hot topic in the 1980s, as it was found to be carcinogenic and to increase during maturation phase of spirits. At the time various whiskies, especially grain or bourbon whiskies from stainless steel column stills were producing spirits with way too much EC and the concentrations seemed only to increase during maturation. It was found that copper in the ascending phase on still decreased EC dramatically and copper was (re)introduced into column stills. Adversely copper salts in the new make does catalyses the EC formation during the maturation, so most grain distillers use only stainless steel in the condensers to diminish the amount of copper residues in the new make. "


Best, think copper in ascending and Stainless in descending.

You can buy a SS Product condenser far cheaper than you can build and they are stack-able. A 4" x 24" product condenser may or may not handle vapor from a 700 gallon boiler, but two or three of them will!

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Hedgebird.

If you do not have a baffle in the top of your condenser then your vapor is only going through a few of your tubes (the ones that are directly below your line arm input). If there is no baffle then the vapor will not spread horizontally outside the diameter of the line arm input pipe. ...............................................................

Ok, if the vapor only goes down the centre tubes a baffle could help spread it to more tubes.

But the main reason it is only going down the centre tubes is because the tubes are not correctly sized, their diameter is too large for the quantity of vapor. Smaller diameter tubes will cause a slight back pressure and the vapor will spread across more tubes.

A baffle as described will help, but with oversize tubes there is not enough turbulence. Turbulence is very important to get good heat exchange.

There are several ways to get a slight back pressure and increase turbulence.

I cut open a swimming pool exchanger and the thin tubes had flat strips of zigzag metal inside them, it increased turbulence as well as conducting a little more heat through the tube wall.

If you are building your own then another way I have seen is to partially crimp oversized tubes every inch or so, every second one at right angles to the previous. This is very easy and as well as increasing turbulence, the average velocity is slow which gives more time for heat transfer.

I am about to build another still and condenser. I am considering using a re-purposed dairy plate exchanger. Those things are VERY effective and cheap.

.

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In the big picture, aren't the ideal or minimal coolant flow rates and temperatures as important as the physical size and design? When everyone is talking sizing here, I understand it's easy to just describe things in terms of height and width, but what's the design coolant flow rate and temp and what's the minimal? Designing a heat exchanger for expensive 75f municipal water is going to be a very different exercise than designing a condenser for a 1500 gallon 50F chilled water reservoir.

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Since, I sell to the public I must design my condensers for 65° water because that is what some of my customers are going to use. Also, I designed the condensers on my pro series stills to handle a 2 hr stripping run with coolant at 65°. That way I know that my customers are never going to be limited by their condensers. If, due to the size of my condensers, my stills cost more, then that would be a problem, however the fact is that when comparing apples to apples my stills cost around 1/2 as much as my competitors. That is not because they are cheaper to build, it is because I keep my overhead low and I am not taking nearly as much profit as my competitors. http://distillery-equipment.com/300_gallon_still.htm

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If they have 65 degree water I normally suggest that they purchase a chiller to chill the water in a chilled water holding tank and that they run the output from their cooling processes into a hot water holding tank for mashing or CIP. That way they utilize the heat energy in the cooling process output water and since the water is used a 2nd time it is like using no cooling water at all. I have several customers who have 55° to 59° well water and they really have it made because it costs them nothing to chill their water. They all use a hot water storage tank for the output from their cooling processes for recycling as mashing in water and or CIP water.

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Exactly my recommendation, with additional caution for the maximum flow drawn out out of the well (I like to put a filter package in if I have any additional exchangers involved- have one like that now where the guy is using old milkhouse reservoir with booster cooling from his low temp chiller & isolation exchanger).

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