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Help with a condenser design


Rickdiculous

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Okay,

So I have built a still from a design a friend come up with inconjunction with Custom Metalcraft using one of their 550 gallon bulk tanks. I sent a schematic for a column and a condenser based on what could easily fit in the corner of the top of the tank to a great local fabricator. So this has a 4 ft x 8inch column with a still dragon dephlemator on top which goes over to the 6 inch by 4 ft condenser via a 3" pipe. When I originally designed it I took a shot in the dark and ran (7) 1 inch by 44 inch tubes evenly spaced down the middle. I did not do any calculations other then generally looking at the ratios of the columns to condensers on Carl's and Vendome's and took a best guess. Needless to say to make this work, it runs very slowly on stripping runs. I started out at about 12 hours and began to push it. My best time was around 6.5 hours and typical is 7.5-8. I had to slow it down because my distillate began to run hot and things started coming out of the vaccuum break on the parrot.

I know that is not a lot of detail, but my thought is to go back to the fabricator and get a new condenser with the layout of tubes in the picture below. I did do some surface area calculations on the tubes. Right now I have (7) 1 inch tubes, 44 inches long with a total surface area of 1627.36 square inches. If I go to the configuration below, I will have (21) .5 inch tubes with a combined surface area of 2935.8 sq/inches. Basically 1.5xs the current surface area. If I add tubes where the x's are, I will get an additional (16) .5 inche tubes for a total of 5172.6 sq/inches or 2.6xs the surface area.

post-1573-0-61545300-1440281301_thumb.jp

So, based on this 550 gallon still, 8"x4 fit column with dephlegmator (plumbed from top of condenser), 6"x 44" tube in shell condenser I get this question:

Which of the two 1/2 inch pipe configurations will give me the most bang for the buck. Is the surface area of the 21 tubes a sufficient gain/ correct for size, or should I add the extra tubes? Is there a diminishing return for too much surface area and volume taken up by the tubes compared to the volume of cooling water within the shell?

I hope this makes sense, and someone with some design savy can help me out.

Thanks,

Rick

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I would check the temperature of the water. What are you using to cool your water. Are you using a evaporation system. A byproduct of a evaporation system is hard water.

Sometimes a evaporation system is used to pre-cool a mechanical system. Be careful with a evaporation system, that is where Legionnaires Disease comes from.

You can also try joseph@dehnerdistillery.com

515-559-4879

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Personally I'd probably just buy a condenser from a reputable builder. I recommend Dehner as he actually owns a distillery, uses his own equipment and has enough experience with seeing first hand what works better. A general fabricator probably has no idea what works best for a distillery and is just shooting from the hip (which probably costs you more money and time).

Or (and please don't take offence), you could keep trying to reinvent the wheel.

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First, you don't say how much power input the still has. That is the first consideration. Without knowing that, no one can determine the condenser size needed.

Once you know that, you can more readily determine the square footage you need. You could also hire an engineer to calculate the ratio of power to square footage needed.

A couple other factors. A longer condenser is better, in general. Think about 60-100 inches, especially if your incoming water temperature is high. It's also good to have baffles inside the condenser to make the water flow more turbulent.

Or for a quick fix, you could add some additional condensers (eg, stilldragon) inline with the vapor pipe, before the main condenser. Run a separate cold water feed to each condenser.

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I have the same question as Ebstauffer.

An efficient condenser / heat exchanger creates turbulence as well as having a large surface area.

Turbulence needs to be inside as well as outside the tubes.

Smaller diameter tubes usually create more turbulence.

The 1 inch tubes on that size still might have enough surface area but the vapor or cooling water is moving slowly so there is little turbulence.

The slower you run the still the less efficient it becomes.

If the cooling water is on the outside of the tubes it also needs turbulence. Higher velocity will help, and baffles to create more turbulence also increase the efficiency.

If you can easily get to the ends of the 1 inch tubes you could try inserting some half inch wide thin stainless strips. Bend the strips into a lot of zig zags and this will increase turbulence and efficiency. Maybe not enough but probably worth a try.

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Okay,

So here area couple of other details to answer some of the questions you guys have

1) Energy to the still comes from a 500K Steam Boiler. It only services this unit.

2) Steam Jacket covers 75 percent of the Still Surface.

3) Cooling water is ground water from a well at 55F/ 13C running at 70 PSI

I could easily put in some strips to the 1 inch columns for the time being.

I looked at the latest pics Joe put up of his condensors and they appear to be just like my pictured design in terms of tube size and configuration. I could put some baffles in for water turbulence as well. That is a good idea.

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Okay,

So here area couple of other details to answer some of the questions you guys have

1) Energy to the still comes from a 500K Steam Boiler. It only services this unit.

2) Steam Jacket covers 75 percent of the Still Surface.

3) Cooling water is ground water from a well at 55F/ 13C running at 70 PSI

I could easily put in some strips to the 1 inch columns for the time being.

I looked at the latest pics Joe put up of his condensors and they appear to be just like my pictured design in terms of tube size and configuration. I could put some baffles in for water turbulence as well. That is a good idea.

Sorry bud but I do not use 1" tubes on my condensers.

You should read the quote "To much or To little". Basically in your situation you could mess around for weeks or months on end trying to fix a problem you could fix with one phone call. Or you could look at it this way, you could spend a whole Lotta money trying to fix your problem and never fix it, or spend the right amount of money on the right part and get it completed.

Just saying.

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