Air Cooled Reflux column, - AKA The Very Silly Still.
Posted: Tue May 17, 2016 4:50 am18 months ago I first mentioned this.
It is finally done.
For anyone interested, some info on my air cooled reflux column, Scroll down to look at the pics and then pour yourself a drink and come back for a read.
My Silly Still (a large version of the Smart Still) is just a 1m x 54mm copper column on an urn, run through a power controller, with a very LARGE air cooled copper condenser.
The new Very Silly Still swaps out that column for a SS scrubbie packed 700mm length of 54mm pipe sitting on a 4" bubble plate, above the packing is a thermowell and then almost 5 metres of coiled 10mm pipe followed by a doo-hickey Swan Neck and Lynn arm.
A piece of timber (I used whisky barrel stave for the fun of it) helps keep it rigid.
The hd.org HETP calculator gives it a HETP value of 8.3 + 1 for the pot , a theoretical vapour purity better than 93.9%. + 1 for the bubble plate, even higher?
The bottom of the 10mm coil has a short length of 8mm soldered inside and protruding down into the 22mm, to ensure that cooled distillate drips/runs into the centre of the packed section. With hindsight this is obiously the busiest part of the column, with all vapour rising and liquid falling through this restriction,virtually a mini bubble plate,this may have been a mistake, or a piece of accidental genious (luck!).
When running, the top section of the column is enclosed in a wooden box, which takes a couple of minutes to assemble with an electric screwdriver.
The bottom of this box has a 6" duct to outside air, near the top is a 6" 25 Watt domestic extractor fan with a short length of duct to the room.
This changes the air in the box twice a second. This was hard to photogragh in place, so one from the side and one from beneath.
The cheap Chinese thermometer in the thermowell is not there to be believed for actual absolute temps, but for relative temps at different stages of a run, something that it is capable of. I have much better thermometers,but they have longer probes, and I did not want to interfere with falling refluxed product..
Touching, (or not! ) the pipes either side of the 'box' and looking at the power controller, gives as much different useful information.
Outside air on the runs so far was 7-8°C, TBH the 10°C temp diff either side of that I can expect year round, with night time air where I am, I believe will not make a great difference, as a temp. diff. of 55°C, is all I believe needed for the reflux condenser to work
I would expect bigger changes from a larger reflux condenser, and re-jigging that short length of 8mm pipe.
So does it work? Yes! well sort of...
I seem to have a similar problem to T500 owners in balancing the cooling power, for them it is someone turning on a tap, for me it is a fridge or freezer kicking in or out, or some such.
It seems to happily knock down everything @ around 570 watts supplied to the boiler, (which is twice the power that I really expected from that length of reflux condenser pipe) but it does not take much more power to have distillate flow from the product condenser.
After equalising,it outputs at a steady 92% from stripped wash at 650 -700W, at just under a litre/ hour.
I struggle to slow it below this rate without it falling back into total reflux due to voltage fluctuations, but have managed 94% @ 620 W and 600ml/h.
Towards the end of the run the take off rate slows,and ABV drops a couple of percent, Kind of weird as I thought that was LM column behaviour,and that this was basically a CM column,using constant cooling of the reflux,and run as a power management still by the ability to regulate the boiler heater. But what do I know?
Whatever, discovering the points at which to increase boiler power are still to be learned.
I have had a few plays with the new toy, I may continue.
The silly still neutral was easy and quick, averaging 67-71% and around 7 litres when the cuts were combined from a couple of stripped neutral washes,and after running through the Essencia was acceptable.
The product from the Very Silly Still does taste a little better, and is at a higher ABV, but seems harder work.
The latest run produced 4.4 litres of very neutral 92% hearts from two of my usual stripped neutral washes.
I am still undecided about it being an improvement, but have proved to myself that it works.
Robert.
It is finally done.
For anyone interested, some info on my air cooled reflux column, Scroll down to look at the pics and then pour yourself a drink and come back for a read.
My Silly Still (a large version of the Smart Still) is just a 1m x 54mm copper column on an urn, run through a power controller, with a very LARGE air cooled copper condenser.
The new Very Silly Still swaps out that column for a SS scrubbie packed 700mm length of 54mm pipe sitting on a 4" bubble plate, above the packing is a thermowell and then almost 5 metres of coiled 10mm pipe followed by a doo-hickey Swan Neck and Lynn arm.
A piece of timber (I used whisky barrel stave for the fun of it) helps keep it rigid.
The hd.org HETP calculator gives it a HETP value of 8.3 + 1 for the pot , a theoretical vapour purity better than 93.9%. + 1 for the bubble plate, even higher?
The bottom of the 10mm coil has a short length of 8mm soldered inside and protruding down into the 22mm, to ensure that cooled distillate drips/runs into the centre of the packed section. With hindsight this is obiously the busiest part of the column, with all vapour rising and liquid falling through this restriction,virtually a mini bubble plate,this may have been a mistake, or a piece of accidental genious (luck!).
When running, the top section of the column is enclosed in a wooden box, which takes a couple of minutes to assemble with an electric screwdriver.
The bottom of this box has a 6" duct to outside air, near the top is a 6" 25 Watt domestic extractor fan with a short length of duct to the room.
This changes the air in the box twice a second. This was hard to photogragh in place, so one from the side and one from beneath.
The cheap Chinese thermometer in the thermowell is not there to be believed for actual absolute temps, but for relative temps at different stages of a run, something that it is capable of. I have much better thermometers,but they have longer probes, and I did not want to interfere with falling refluxed product..
Touching, (or not! ) the pipes either side of the 'box' and looking at the power controller, gives as much different useful information.
Outside air on the runs so far was 7-8°C, TBH the 10°C temp diff either side of that I can expect year round, with night time air where I am, I believe will not make a great difference, as a temp. diff. of 55°C, is all I believe needed for the reflux condenser to work
I would expect bigger changes from a larger reflux condenser, and re-jigging that short length of 8mm pipe.
So does it work? Yes! well sort of...
I seem to have a similar problem to T500 owners in balancing the cooling power, for them it is someone turning on a tap, for me it is a fridge or freezer kicking in or out, or some such.
It seems to happily knock down everything @ around 570 watts supplied to the boiler, (which is twice the power that I really expected from that length of reflux condenser pipe) but it does not take much more power to have distillate flow from the product condenser.
After equalising,it outputs at a steady 92% from stripped wash at 650 -700W, at just under a litre/ hour.
I struggle to slow it below this rate without it falling back into total reflux due to voltage fluctuations, but have managed 94% @ 620 W and 600ml/h.
Towards the end of the run the take off rate slows,and ABV drops a couple of percent, Kind of weird as I thought that was LM column behaviour,and that this was basically a CM column,using constant cooling of the reflux,and run as a power management still by the ability to regulate the boiler heater. But what do I know?
Whatever, discovering the points at which to increase boiler power are still to be learned.
I have had a few plays with the new toy, I may continue.
The silly still neutral was easy and quick, averaging 67-71% and around 7 litres when the cuts were combined from a couple of stripped neutral washes,and after running through the Essencia was acceptable.
The product from the Very Silly Still does taste a little better, and is at a higher ABV, but seems harder work.
The latest run produced 4.4 litres of very neutral 92% hearts from two of my usual stripped neutral washes.
I am still undecided about it being an improvement, but have proved to myself that it works.
Robert.
...
