3" to 4" back to 3"

[Mord]

Is there any reason why going from a 3" column 18" long to a 4 plate bubble plate 18" long back down to a 3" refulx wouldn't work? Pot is a 15 gallon with 5500w element with controller. Would it be better to just stay all 3"?

[Mord]

Forgot to mention that the bubble plate is 4". Everything else is 3".

[Newtothis]

Watching with anticipation as I have been wondering the same thing with a onion head.

[bluefish_dist]

It will work. You will be limited by the most restrictive portion for takeoff speed. If it’s packed 3” and plated 4”, that will probably balance ok. My still heads reduce down to 2” from 4” and then back up to 3” for the condenser. I also run a 4” column over a 6” plate. It’s not as fast as a 6”, but the 6” plate runs fine at 4” speeds.

[RC Al]

I would be putting the 3" above the plates if its packed.

If its empty, its just a riser and of little consiquence.

The onion head is a great way to provide a small amount of reflux and copper contact for a pot still, if its up away from the boiler you might get a tiny bit more reflux (very small numbers), imho of questionable use on a packed reflux still

[jonnys_spirit]

I would be putting the 3" above the plates if its packed.

If its empty, its just a riser and of little consiquence.

The onion head is a great way to provide a small amount of reflux and copper contact for a pot still, if its up away from the boiler you might get a tiny bit more reflux (very small numbers), imho of questionable use on a packed reflux still

Unless you pack the onion head too...

Cheers,
j

[Saltbush Bill]

Is there any reason why going from a 3" column 18" long to a 4 plate bubble plate 18" long back down to a 3" refulx wouldn't work? Pot is a 15 gallon with 5500w element with controller. Would it be better to just stay all 3"?

A bit better explanation of what your trying to achieve here would be helpful.

I would be putting the 3" above the plates if its packed.

[Mord]

Is there any reason why going from a 3" column 18" long to a 4 plate bubble plate 18" long back down to a 3" refulx wouldn't work? Pot is a 15 gallon with 5500w element with controller. Would it be better to just stay all 3"?

A bit better explanation of what your trying to achieve here would be helpful.

I would be putting the 3" above the plates if its packed.

The price of a 3" and 4" aren't that far off if you order from china and are willing to wait over a month. My thinking was that I could run the 4" plates a bit faster.

[Saltbush Bill]

So in short your wanting to run a four inch 4 plate column with a packed section on top to make neutral?, doubt you will need all 5500w, will more than likely need to buy a controller

[Yummyrum]

My thinking was that I could run the 4" plates a bit faster.

You can only run 4” plates at around 3kW . After that , they pull through tails and defeat the purpose of using them at all . However , you could run a 3” packed column at much higher power than that .

As Saltbush said , you’ll need a controller to find the balance .

I’ve never been a fan of Packed column over plates . They are a compromise . If you want Neutral , a packed column reflux still is the best choice .

[Mord]

I do run a controller on it. Thanks for all the input everyone you've geen a great help!!! Keep on rocking in the free world!

[bluefish_dist]

My thinking was that I could run the 4" plates a bit faster.

You can only run 4” plates at around 3kW . After that , they pull through tails and defeat the purpose of using them at all . However , you could run a 3” packed column at much higher power than that .

As Saltbush said , you’ll need a controller to find the balance .

I’ve never been a fan of Packed column over plates . They are a compromise . If you want Neutral , a packed column reflux still is the best choice .

I run my 4” sieve plates much faster than 3kw. My stilldragon bubble caps flooded about 4kw and the pro caps were good to 5.5kw. Sieve ran 5.5-6kw. I also ran my 4” packed about the same speed over low wines, slightly slower over wash.

[Saltbush Bill]

doubt you will need all 5500w, will more than likely need to buy a controller

You can only run 4” plates at around 3kW . After that , they pull through tails and defeat the purpose of using them at all .

I run my 4” sieve plates much faster than 3kw.

Sieve ran 5.5-6kw.

Well there you go Mord, 2 very different opinions to the same question, suggest that you try both ways, and get back to us about what you think works best.
I'm in Yummys corner, any more than about 3200 and things will get interesting fast in my opinion.
I for one will be interested to hear your feedback.

[bluefish_dist]

I know my power rates seem high, but I ran a lot of reflux. If I was running 3 plates, I would hold output at 165-170 proof or no more than 173f at 6200 ft. If the temp went over that, I would increase reflux. Never had a problem pulling tails up the column. Only limit was flooding.

[juana_b]

Refining lentils do exactly that, increase then decrease diameter. Generally not used with plates, though.
viewtopic.php?f=15&t=59658

[shadylane]

For a neutral, instead of stacking a packed section on top plates for a one run and done.
I'd run the packed column at a low reflux ratio for stripping, then dilute and run it again with the column.