Many people and distilleries have height restrictions. Home distillers normally overcome this with using smaller diameter to match their height available. Commercial distilleries regularly use side columns to get enough height/length to match their purity and production speed goals.
I built this 4" x 60" CM using Siporax Pro for packing and have been happy with it....but I wanted to make it better.

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The current still was producing at 10.5 liters per hour around 95%. I believe this will increase those numbers.
I wanted to increase the length of the column but I am already at the ceiling. I also wanted to get the boiler off the floor for cleaning but that would have stolen precious column height. I have built side columns before and actually have a 4 plate side column still as my primary still. So building another one seemed like some more building fun.
By not using a gravity return drain I could start the column almost at the floor and get much better efficiency from the columns. The idea is to have a packed column that sits on the boiler ( column #1) and the outlet of column #1 would feed into the base of the packed side column (column #2). Both columns have dephlegmators but I will only use the dephleg on column #2. As the reflux/condensate drains down to the bottom of column #2 into a collector a variable speed stainless steel gear pump will pump it up to a spray head just below column #1 dephleg. By doing it this way it should work as one single column minus a little inefficiency from piping going from column #1 to #2. I have now gone from a 5' column to a little over 11' column and my boiler is off the floor.
This is what it looked like before polishing powder coating and a ton of other work