First VM Design - Comments?

[noodrid]

So here is my design for a VM still. Basically it's stainless steel with copper scourers for packing. Reason is it is a lot easier for me to get a hold of and work with SS. The column is 3" diameter. Boiler is a 62L stainless pot (16gal).

Dimensions are in mm (sorry).
Before anyone says anything, the glass condenser is laboratory grade and has never been used. I had it lying around so that's why I want to use it. It's about 500mm long and 3 concentric coils, so I'm confident it will be able to do the job. I'm planning to have a piece of SS machined to fit into the top to connect it - so no glues etc. There shouldn't be any other issues with this should there?

The main question I have are:

1) Should there be anything in the packing to help redistribute the flow of liquid through it. I get the feeling channeling will be a problem over the length of the column, but thought I'd ask.

Any comments/advice are appreciated!

[rad14701]

A taller packed column section would allow for higher purity...

A larger diameter take off branch might provide better performance...

We don't consider the use of lab glass components to be the safest way to go... You probably already know that but it's worth reiterating for any novices stumbling across this topic... Copper or Stainless Steel... Very few here practice this craft in laboratory environments and knowing that glass can break makes for a potentially unsafe scenario... If it breaks you have very high proof explosive spirits all over your stilling area... Investing in a metal product condenser would be a safer option... Just sayin...

[skow69]

Rad is right about the takeoff tube. Assuming the column is 2" your reflux ratio will limit at 4:1. The other solution is reducing to a 1X1X1 tee at the takeoff. I wouldn't be concerned about channeling. There is so much turbulence in the column. Also, the machined disk at the top is unnecessary.

[DAD300]

I agree...the disk at the top will hamper or stop reflux penetration.

[rad14701]

A 3x1x3 would have a minimum reflux ratio of 9:1... A 3x2x3 would have a minimum 2.25:1 reflux ratio...

[skow69]

Oops. I missed the "The column is 3" diameter." in the text. Rad is right. Another other solution would be reducing to a 2x2x2 tee at the takeoff for approx. 1:1 reflux ratio and better output.

[T-Pee]

Is this a slant plate? What directs the distillate to the takeoff?

tp

[skow69]

VM magic.

[noodrid]

Thanks for the input everybody! Will change the takeoff to 2".