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Re: Automate distilling process

Posted: Thu Mar 16, 2017 11:55 am
by Pikey
Thanks for that plato, good to hear from someone "in the trade" as it were. I deliberately kept away from specifics, since it was not my intention to publish something anyone less competent may feel they could use as a design, on the basis of 5 minutes of my idle cogitation.

Not everyone runs reflux though and so the option to use water as a control mechanism does not exist for many and many DO run propane irrespective of what you or I may feel about that. Electronic gas valves do tend to be on the pricey side and complicated.

NZChris came up with the latched relay system in the post after mine if I remember correctly. And going silicon, is not a bad idea, but you'd still need to build a triac or paired thyristor circuit to drive them in AC configuration, as well as your amplified comparator sensor switching and of course silicon switches can fault short as well as open circuit !

My apparatus does not need adjusting as it progresses at all and all I really do is "Switch jars" at relevant stages. That could be automated in fact, since I tend to do it by quantities and temperatures, depending on the stage. in any case with a system of valves and a timed cutoff at simplest, although I would use head temperature myself as cutoff (You can actually run head temperatures well over 100 C although I have never gone above about 103, since the yield is by then small. )

I understand what you say, and you may have the best gate in the world, but will you then ignore the phone call from your neighbour saying "Your horse is in the lane ..." ?

Could I build a system ? - undoubtedly. Will I ? Nope - Life's too short to automate something you can't leave on it's own and I can't be arsed ! :lol:

We all tend to be a bit "enterprising maveric" in nature in this hobby, and have had to learn a lot and learn to do things which may have been outside our comfort zone in getting where we are, so saying "get a technician in" will just be seen as a "challenge" to many !

Anyway, thanks a lot for your views, I've enjoyed this thread and perhaps we've all learned something.

I for one will be considering an ethanol sensor alarm, and cooling water sensors. (other than just holding on to the end of my copper coil occasionally ! )

Re: Automate distilling process

Posted: Thu Mar 16, 2017 12:26 pm
by NZChris
plato wrote:>>>Pot Pressure
Isn't a reliable indicator that you are safe... and isn't a particularly useful parameter to monitor from a control perspective
High pressure in a pot is a reliable indicator that you are not safe.

Re: Automate distilling process

Posted: Thu Mar 16, 2017 12:49 pm
by NZChris
plato wrote:>>>Pot temperature
A temperature switch on the pot would be useful to tell you when a run is ended (no point pushing it beyond 99C) , but not so much from a safety perspective (another matter of horses and gates).
I regularly run mine to 100C to get low wines to 30% and below for flavored products.

Safety wise, an unexpectedly high boiler temperature indicates pressure and can be used to shut the heat off.

Re: Automate distilling process

Posted: Thu Mar 16, 2017 1:13 pm
by Pikey
NZChris wrote:
plato wrote:>>>Pot temperature
A temperature switch on the pot would be useful to tell you when a run is ended (no point pushing it beyond 99C) , but not so much from a safety perspective (another matter of horses and gates).
I regularly run mine to 100C to get low wines to 30% and below for flavored products.

Safety wise, an unexpectedly high boiler temperature indicates pressure and can be used to shut the heat off.
DO you Chris ? So you use the low alcohol part between 90 -100 C to Lower the overall abv of your low wines ?

I usually stop mine at head temp 100 ish at which time the boiler is around 91 ish. But then I do single runs and the last portion is only producing feints to go back into the next run as far as I am concerned. At 100 C head, the distillate is just below 30 abv so there's virtually nowt left in there as far as I'm concerned. :( - Except Flavour you're saying ? Gonna have to try one of these double runs :( You running pot mode or reflux ?
Edit:

Re: Automate distilling process

Posted: Thu Mar 16, 2017 1:17 pm
by der wo
I do it like NZChris. Stripping to 100°C or even higher. Yes, the temp can rise a bit further.

Pikey, are the numbers really correct? Boiler is 91° and head 100°? Do you have a heating element between boiler and head???

Re: Automate distilling process

Posted: Thu Mar 16, 2017 1:25 pm
by NZChris
Stripping with a pot still, I run into a single vessel with an alcometer floating in it and run until it reaches my desired abv for the low wines. This usually has the boiler temperature close to, or at, 100C at shutdown, close enought that 100C could be used to automate shutdown. Note that this is for my setup, using a preheater, yours may behave slightly differently. The preheater is distilling towards the end of each strip, putting out more alcohol than the main boiler, so the extra heat to get to 100C isn't totally wasted.

I have had all molasses rum washes go over 100C.

Re: Automate distilling process

Posted: Thu Mar 16, 2017 2:18 pm
by Pikey
der wo wrote:I do it like NZChris. Stripping to 100°C or even higher. Yes, the temp can rise a bit further.

Pikey, are the numbers really correct? Boiler is 91° and head 100°? Do you have a heating element between boiler and head???
Yes absolutely correct der wo - The head temp starts getting away from teh boiler temp as soon as foreshots are done.

It is based on a modified tea urn of 25 litres.

I don't quite know how I managed to "fluke it" on my first build, but I did !

It's a 1" offset in theory, but as was pointed out to me in "my first" the reflux return is too low to be "proper" - So I run it as a pot ! And I love the way it works !

When I put packing in the column, My distillate starts well over 80% but fades quickly.

Without packing, and without insulation, the column gets quite hot and I'm assuming that is due to the thin column acting as a sort of air cooled liebig type Dephleg and recondensing some of the vapour (mainly water). The released LAtent Heat of Vapourisation then raises the temperature of the rest of the vapour. It is 40" (1 metre) to the offset and the distillate starts about 68-70 abv. It holds up rather well at 60 abv or a little over until my hearts are over, when my head temp is 95 or 96 depending what I'm running. Then I cut to tails and stop at head 100 ish or when abv drops below 30.

resized.jpg




PS it's an old photy at our old place - do not worry about the wire trailing from the head - that's when I thought you could use head temp to govern the alcohol strength :roll:

And the funny bit of stuff over the open coolin coil was me thinking ethanol would escape from there. It's been a big learning curve :lol:

Re: Automate distilling process

Posted: Thu Mar 16, 2017 2:53 pm
by Pikey
Chris, that system of yours sounds amazing !

You actually get distillate from the preheater ? - So that is not plastic as I thought, but stainless I suppose ? By my standards you are saving at least 1/4 of your heat costs, water costs as you've said elsewhere and most importand TIME ! - I really would like to get my head around your system properly 8) - Sounds like the "way to go" - or at least to learn from.

It seems that even thoufgh we may not have "sensors" as such in our vatious systems, we are "automating certain decisions in our own ways and thus staying on subject. Very informative thread :thumbup:

Re: Automate distilling process

Posted: Thu Mar 16, 2017 3:27 pm
by Kareltje
cranky wrote:
Kareltje wrote:@cranky: I do not agree: the heat that is needed to vapourize a certain amount, is regained or dissipated by the condensation of the same amount. Be it water or alcohol.
What you seem to fail to understand is that as the alcohol comes out of the wash it takes more energy to heat that wash to keep it boiling to keep vapor coming out so the amount of vapor produced drops off and less vapor requires less cooling.
Assuming that there is no energy needed to compensate the loss from kettle to air, all the energy goes into vapourizing water and alcohol. And that energy must be lost by cooling in the condenser.
The amount of vapour or fluid or the ratio water/alcohol do not matter: the vapour produced in the boiler has to be condensed.
When the energy dissipated in the cooler starts to diminish, the energy going from boiler to condenser is diminishing, while the energy input from the burner is steady. So there must be an energy-sink.
Maybe the rising temperature and so the heatloss from kettle to environment plays some role.
Kareltje wrote:Inefficient? Distilling is inefficient by definition. By cooling you remove and waste the heat you put in the vapourizing of alcohol. Whether you remove this heath by air or water is not relevant: it is removed and wasted. (Although I heard of someone who used the hot water to clean his terrace. I could use it to fill a bathtub.)
Yes inefficient because it cannot cool as fast, as well or as much in a short period of time as a jacket liebig or a proper flake stand with a reservoir or even a fan cooled air condenser. I run a recirculation system, my setup is much larger than yours with a reflux coil as well as a product condenser, so I use 2 reservoirs, a 50 gallon and a 30 gallon. I clean and refill it once a year and lose less than 20 gallons a year due to evaporation for a total of less than 100 gallons a year used to run everything I feel like running. When I ran a pot head I only needed the 30 gallon to cool a 13 gallon run, I never controlled the pump it just circulated so it was turn on the pump and turn it off when it was over and often could do 2 runs back to back without getting too hot. I could also strip a 13 gallon wash in under 1.5hr and do a spirit run in well under 3. When I ran a small 4 gallon pot a 5 gallon bucket of water was sufficient to take care of a run. I feel it is much less efficient and much more wasteful to continue heating something for a greatly extended amount of time just so you don't have to use 5 gallons of water to cool it.
Ah, I would like to make such systems. Reusing the heat!

I wonder if you are right, I am not sure. Short time and high pressure vs. long time and low pressure.
Or: low energy and long time air condenser vs high energy and short time water condenser.
Apart from the reusing of the heat.

Re: Automate distilling process

Posted: Thu Mar 16, 2017 4:39 pm
by NZChris
Kareltje wrote:The amount of vapour or fluid or the ratio water/alcohol do not matter: the vapour produced in the boiler has to be condensed.
When the energy dissipated in the cooler starts to diminish, the energy going from boiler to condenser is diminishing, while the energy input from the burner is steady. So there must be an energy-sink.
Maybe the rising temperature and so the heatloss from kettle to environment plays some role.
Except for a slight increase in heat loss through the walls or insulation, the energy going from boiler to condenser does not diminish during a run if the energy input from the burner is steady. There is no energy-sink.

Re: Automate distilling process

Posted: Fri Mar 17, 2017 2:27 am
by der wo
Pikey wrote:Without packing, and without insulation, the column gets quite hot and I'm assuming that is due to the thin column acting as a sort of air cooled liebig type Dephleg and recondensing some of the vapour (mainly water). The released LAtent Heat of Vapourisation then raises the temperature of the rest of the vapour. It is 40" (1 metre) to the offset and the distillate starts about 68-70 abv. It holds up rather well at 60 abv or a little over until my hearts are over, when my head temp is 95 or 96 depending what I'm running. Then I cut to tails and stop at head 100 ish or when abv drops below 30.
The heat of the uninsulated column is released to the ambient air. So a part of the vapor condenses and flows back down the column. This vapor gets redistilled by the rising vapors -> higher abv / lower temp. The temp can only get lower due to reflux not hotter. If you have realy a higher temp at the top of column than in the boiler, one of the thermometers is WAY off.
At "100 ish" the abv is zero not "below 30". I would distill once water and look what the themometers measure. Both at any position should measure 100°C.

Re: Automate distilling process

Posted: Fri Mar 17, 2017 3:07 am
by Pikey
I think I will try to put it a different way when I return from a journey I need to make.
I will also post a photo of both thermometers readings in the same container of liquid. - They will be the same (ish)
The latent heat of vapourisation is released when a steam type gas is condensed. It is the reason why steam burns are far more severe than water burns.

Re: Automate distilling process

Posted: Fri Mar 17, 2017 11:05 am
by Pikey
My thermometers in a cup off hot water - I hope you can make them out. That on the meat thermo measuring 43.5 (HEad temp), whilst that on my Power controller box (Boiler temp) measures 43.7. Near enough - No ?
thermo resize.jpg






When the head temp measures 100C - the abv of the distillate is +/- 30 % as stated. If the boiler temp was really 100C at this time, the distillate would be as der wo stated very close to 0% abv.

I am quite sad that there seems to be a disbelief of what I said, since it is a repeatable and consistent observation over numerous runs. At 100C (Head temp) the boiler temp is just over 90. That is at first sight counter-intuitive. Clearly this apprent anomaly puzzled me too at first, until I came out with a thought out solution to the issue.

I do have A Level Physics, and do understand the principles of Evaporation and condensation, as well as most. As far as I can see, the only acceptable explanation can be that some of the evaporated water condenses on the walls of the column, releasing it's Latent heat (Approximately 2.26 KJ/gramme) This has no alternative but to raise the tube temperature, since there is no cooling coil within the tube. Some of that water may be re-evaporated as der wo suggests, but since there is no packing, most will run down the walls and drop back in the boiler. The hot tube will now raise the temperature of gas passing it by radiaion or conduction. Some will be transferred through the wall of the tube by conduction and dissipated into the air as suggested, but not all.

The parent site has also obsereved that the alcohol content of distillate in a pot still is increased by having a taller pot head as I remember. This would be down to the same reasoning imho.

If anyone can see a different explanation for this very real phenomenon, please do post it. :)

Re: Automate distilling process

Posted: Fri Mar 17, 2017 11:24 am
by der wo
http://homedistiller.org/theory/theory/strong" onclick="window.open(this.href);return false;" rel="nofollow
Vapor with 30% should have 97°C.

There is no disbelief of your observation. But I think there must be a mistake.
Pikey wrote:As far as I can see, the only acceptable explanation can be that some of the evaporated water condenses on the walls of the column, releasing it's Latent heat (Approximately 2.26 KJ/gramme) This has no alternative but to raise the tube temperature, since there is no cooling coil within the tube. Some of that water may be re-evaporated as der wo suggests, but since there is no packing, most will run down the walls and drop back in the boiler. The hot tube will now raise the temperature of gas passing it by radiaion or conduction. Some will be transferred through the wall of the tube by conduction and dissipated into the air as suggested, but not all.
But why does this happen only with your still? We all loose temperature with rectification. When I reflux 100%, the temp drops, when I reflux 0%, the temp rises, in opposite the abv, exactly like shown by the distillate strength chart.
Pikey wrote:The parent site has also obsereved that the alcohol content of distillate in a pot still is increased by having a taller pot head as I remember. This would be down to the same reasoning imho.
Yes. Taller riser -> more condensing -> more rectification -> higher abv and lower temp

Re: Automate distilling process

Posted: Fri Mar 17, 2017 11:30 am
by NZChris
Pikey wrote:If anyone can see a different explanation for this very real phenomenon, please do post it. :)
The manufacturor of your STC-1000 only claims -/+ 1C accuracy between -50C to 70C, so if you are using it over 70C, you should calibrate it at the range you want it to read. I haven't found them accurate enough to be useful at distilling temperatures.

Re: Automate distilling process

Posted: Fri Mar 17, 2017 12:50 pm
by Pikey
NZChris wrote:
Pikey wrote:If anyone can see a different explanation for this very real phenomenon, please do post it. :)
The manufacturor of your STC-1000 only claims -/+ 1C accuracy between -50C to 70C, so if you are using it over 70C, you should calibrate it at the range you want it to read. I haven't found them accurate enough to be useful at distilling temperatures.
Ok - that's interesting but I think I can answer that one Chris. When I first started, I used that and another the same, as column head sensors, in conjunction with the meat thermo. The sensors lagged the meat thermo time wise by several seconds (sampling rate? ), but was within a degree or so temp wise, so if I set it to shut off at 86 C, the meat thermo was perhaps at 87 by the time it did so. I could try them both in boiling water. perhaps I will when I think about this some more.

Re: Automate distilling process

Posted: Fri Mar 17, 2017 1:18 pm
by Pikey
der wo wrote:http://homedistiller.org/theory/theory/strong
Vapor with 30% should have 97°C.

There is no disbelief of your observation. But I think there must be a mistake.....
That chart does seem compelling der wo.

I'm convinced my 1" column is relevant. Perhaps though for different reasons than I surmised. I'm now wondering if I am getting Radiant heat from the copper affecting the head reading ? And my sensor is strapped to the outside of the boiler. I shall insulate it better for the next time I use it - from those boiling temperatures, it does seem that I should not be getting vapour at the temperatures I am stating as boiler temps, although they are consistent from one run through the next ten. If I have to, I'll drill a hole in the boiler top and hang the other inside on a water run as well. We know that should be starting at around 100.

I don't think I'm actually claiming to be Gaining heat der wo. Temperature rising yes, but a lot of heat taken out of the water running back down to the boiler, so apparently a surplus of heat energy Left at the column head, by the condensing fluid. You have water filled coils at the column head though, which are there with the espress purpose of removing heat from the vapour, I do not. Does that water keep running whether you are refluxing at 100% or at 0% ?

I'll consider what I can do to verify or otherwise my readings. Maybe a water run is called for ?

[Edit - Do we think a run of water in the boiler, without the top on, but the sensor connected as normal would do it ? Then I could SEE when the water was boiling and read the sensor at the same time ]

Re: Automate distilling process

Posted: Sat Mar 18, 2017 2:33 am
by der wo
Pikey wrote:I'm convinced my 1" column is relevant. Perhaps though for different reasons than I surmised. I'm now wondering if I am getting Radiant heat from the copper affecting the head reading ? And my sensor is strapped to the outside of the boiler. I shall insulate it better for the next time I use it - from those boiling temperatures, it does seem that I should not be getting vapour at the temperatures I am stating as boiler temps, although they are consistent from one run through the next ten. If I have to, I'll drill a hole in the boiler top and hang the other inside on a water run as well. We know that should be starting at around 100. Perhaps we should discuss further, when you have made this experiment. Can you swap the thermometers during the run?
I don't think I'm actually claiming to be Gaining heat der wo. Yes, gaining heat is impossible I think too. Temperature rising yes, but a lot of heat taken out of the water running back down to the boiler, so apparently a surplus of heat energy Left at the column head, by the condensing fluid. You have water filled coils at the column head though, which are there with the espress purpose of removing heat from the vapour, I do not. Does that water keep running whether you are refluxing at 100% or at 0% ? Yes, it's a LM, the water keeps running same regardless of 0 or 100% reflux. But anyway, is there a difference between cooling with water inside the column or with air outside? Both suck the heat and the heat goes either down the drain or is blown away.

I'll consider what I can do to verify or otherwise my readings. Maybe a water run is called for ? Yes, please.

[Edit - Do we think a run of water in the boiler, without the top on, but the sensor connected as normal would do it ? Then I could SEE when the water was boiling and read the sensor at the same time ] The top of the offset where the coil is should be open always at a LM or VM. If it is really steam tight you would have benn run into massive problems if your product outlet would have a valve (what such a still normally has). But this coil is only outside the column? Then it is probably not enough to knock all the vapor down and you would loose vapor. But no matter for experimental distilling water. Any setup with or without flaws should measure 100°C at any point of the still. Don't you hear it when it boils? When the upper thermometer shows a sudden rise of the temp, it has begun to boil. The termometer should measure within a few seconds 100°C and doesn't change it anymore.
Anyway, I hope, it is not your last still.
We are so massive off topic. Perhaps after your water run it's better to open a new thread with the results.

Re: Automate distilling process

Posted: Sat Mar 18, 2017 2:48 am
by Pikey
Rest assured for the moment on those points der wo.

Thanks to both you and Chris for these disussions 8)

I SHALL return ! :wink: :D

Re: Automate distilling process

Posted: Mon Mar 20, 2017 3:30 pm
by Kareltje
cranky wrote:
Kareltje wrote:@cranky: I do not agree: the heat that is needed to vapourize a certain amount, is regained or dissipated by the condensation of the same amount. Be it water or alcohol.
What you seem to fail to understand is that as the alcohol comes out of the wash it takes more energy to heat that wash to keep it boiling to keep vapor coming out so the amount of vapor produced drops off and less vapor requires less cooling.
I thought so too, in the past. But about a year ago I made a model to find out how it worked and I found something strange and counterintuitive.
The model calculates vaporization of a wash step by step. The amount and content of the vapour can be calculated and so the remaining amount and strength of the wash. So the amount and strength of the next portion of vapour. I start with a heated wash and assume all energy is going into the vaporization.
Starting with 9 litres of 12 %ABV and steps of 300 J. And of course the physical constants of water and alcohol.
The first step gives 0.198 kg vapour with a volume of 849 litres, resulting in a condensate of 0.226 litres at 58 %ABV.
In the last step there is 6.276 litre at 0.86 %ABV in the boiler, the vapour is 0.140 kg and 1,186 litres, resulting in a condensate on 0.143 litres at 9 %ABV.
So although the mass of the vapour diminishes, the volume grows bigger! And, most important: in every step 300 J is transferred from boiler to condenser, so in every step the condenser has to disperse the same amount of energy.

The model I used to calculate from %ABV in the fluid to %ABV in vapour is quite good, but I did not take into account the contraction of alcohol and water. This does not alter the general picture, though.
Some other factors I neglect are the change in volume in the boiler (from 9 litres to 6.3 litres in a 10 litre boiler) and the growing heatloss caused by the rising temperature (90 dg C to 100 dg C).
Thanks to the rethinking I now think that these factors might cause more reflux in boiler and the ascending part, so there is less heat going into the descending part.
Kareltje wrote:
Inefficient? Distilling is inefficient by definition. By cooling you remove and waste the heat you put in the vapourizing of alcohol. Whether you remove this heath by air or water is not relevant: it is removed and wasted. (Although I heard of someone who used the hot water to clean his terrace. I could use it to fill a bathtub.)
Yes inefficient because it cannot cool as fast, as well or as much in a short period of time as a jacket liebig or a proper flake stand with a reservoir or even a fan cooled air condenser.
...explanation....
I feel it is much less efficient and much more wasteful to continue heating something for a greatly extended amount of time just so you don't have to use 5 gallons of water to cool it.
Maybe you have a point.
Last week I bought a still with a watercooled condenser, so I might test this aspect sometime.

Re: Automate distilling process

Posted: Mon Mar 20, 2017 4:22 pm
by der wo
Kareltje wrote:Starting with 9 litres of 12 %ABV and steps of 300 J. And of course the physical constants of water and alcohol.
The first step gives 0.198 kg vapour with a volume of 849 litres, resulting in a condensate of 0.226 litres at 58 %ABV.
In the last step there is 6.276 litre at 0.86 %ABV in the boiler, the vapour is 0.140 kg and 1,186 litres, resulting in a condensate on 0.143 litres at 9 %ABV.
So although the mass of the vapour diminishes, the volume grows bigger! And, most important: in every step 300 J is transferred from boiler to condenser, so in every step the condenser has to disperse the same amount of energy.
Very interesting. I am not sure what it means for practice, but it's very interesting. I never thought about, that the difference between vapor mass and vapor volume could be such different depending on alcohol content.

Re: Automate distilling process

Posted: Mon Mar 20, 2017 4:31 pm
by Kareltje
I was surprised too.
But 1 kg of water makes 1.243 l of vapour, while 1 kg of ethanol makes only 487 l of vapour.

Re: Automate distilling process

Posted: Tue Mar 21, 2017 3:58 am
by der wo
Perhaps this is the real reason for huffing condensers while distilling water or during end of the run. More difference between vapor and liquid volume -> more movement, vapor collapses, action -> more huffing.

Re: Automate distilling process

Posted: Thu Mar 23, 2017 1:42 am
by Pelson
Thanks for all that Plato. Creates a clear image of what it would take to really do it.

It's cool to have you, with your background, give your opinion. I was playing with the idea to automatize the still and then send information to a computer (or maybe even a phone, but that would be less practical).
You could perfectly build a still that is remote-operated, but still monitored at all times. (not much unlike a lot of big industrial processes).
I do agree however that it would take a lot of knowhow or training and experience to set this up yourself at home. But it just seems so cool!

I should've studied engineering instead of pure chemistry.

That being said I do think it would be interesting to link a couple sensors to your still and to gather data to learn more about what your still is doing.
To go from there to (full) automatic distillation is indeed quite the leap.

Thanks everybody for the passionate replies. It's been a while since I've been on this forum (and since I've distilled) but it's awesome to see that this community is still going strong ;)

Re: Automate distilling process

Posted: Thu Mar 23, 2017 8:51 am
by Boda Getta
"12 - 20% wash"
Sounds more like low wine abv than a wash
Turbo yeast?

BG

Re: Automate distilling process

Posted: Mon Mar 27, 2017 2:53 pm
by Kareltje
NZChris wrote:
Kareltje wrote:The amount of vapour or fluid or the ratio water/alcohol do not matter: the vapour produced in the boiler has to be condensed.
When the energy dissipated in the cooler starts to diminish, the energy going from boiler to condenser is diminishing, while the energy input from the burner is steady. So there must be an energy-sink.
Maybe the rising temperature and so the heatloss from kettle to environment plays some role.
Except for a slight increase in heat loss through the walls or insulation, the energy going from boiler to condenser does not diminish during a run if the energy input from the burner is steady. There is no energy-sink.
I thought so too.
But I tested my new still with water, both half and completely filled. And without or with insulating mantle.
From gas till distillate without mantle the efficiency was about 18 %, with mantle it was about 36 %.
So the loss in the boiler and the system before the downward path is either 82 or 64 % of the energy input.
This was measured at 100 dgr C: a gradient of 80 dgrC with ambient air. A wash of 12 %ABV has a boiling point of 92 dgrC, so a gradient of 72 dgrC,which is 10 % less. So while distilling with an input of 1.000 kJ the loss will enlarge with some 10 % of 650 kJ is about 20 % of the distillate of 350 kJ.
As this 350 kJ is cooled in 10 windings of my spiral, 20 % less loss means 2 windings crawl back.

Depending on the system the heat loss during a run can be of some importance.
My first still I ran without any isolation at all. So with a very large energy sink of about 80 %.

It seems I finally understand how this still behaved.
Thank you.

Re: Automate distilling process

Posted: Mon Mar 27, 2017 3:00 pm
by Kareltje
der wo wrote:Perhaps this is the real reason for huffing condensers while distilling water or during end of the run. More difference between vapor and liquid volume -> more movement, vapor collapses, action -> more huffing.
Today I tried a watercooled condenser for the first time and heard the huffing.
When I ran the cooling water quite fast, the condenser huffed. When I ran it very slowly the condenser felt hot but the huffing stopped.
There is a lot to learn about watercooled condensers.

Re: Automate distilling process

Posted: Tue Mar 28, 2017 12:22 am
by der wo
Kareltje wrote:
der wo wrote:Perhaps this is the real reason for huffing condensers while distilling water or during end of the run. More difference between vapor and liquid volume -> more movement, vapor collapses, action -> more huffing.
Today I tried a watercooled condenser for the first time and heard the huffing.
When I ran the cooling water quite fast, the condenser huffed. When I ran it very slowly the condenser felt hot but the huffing stopped.
There is a lot to learn about watercooled condensers.
This is called the shock cooling problem here. For example if you have a very small condenser which needs much water to cool down everything, you have this. Or when your condeser is all right, but you crank up the water just for fun.

Re: Automate distilling process

Posted: Fri Apr 07, 2017 1:40 pm
by papapro
der wo wrote:I do it like NZChris. Stripping to 100°C or even higher. Yes, the temp can rise a bit further.


Going that high get you higher alcohols one of them is isopropyl here is some info from wiki,

Isopropyl alcohol forms an azeotrope with water, which gives a boiling point of 80.37 °C (176.67 °F) and a composition of 87.7 wt% (91 vol%) isopropyl alcohol. Water-isopropyl alcohol mixtures have depressed melting points.[7] It has a slightly bitter taste, and is not safe to drink.

Re: Automate distilling process

Posted: Fri Apr 07, 2017 2:51 pm
by NZChris
papapro wrote:
der wo wrote:I do it like NZChris. Stripping to 100°C or even higher. Yes, the temp can rise a bit further.


Going that high get you higher alcohols one of them is isopropyl here is some info from wiki,

Isopropyl alcohol forms an azeotrope with water, which gives a boiling point of 80.37 °C (176.67 °F) and a composition of 87.7 wt% (91 vol%) isopropyl alcohol. Water-isopropyl alcohol mixtures have depressed melting points.[7] It has a slightly bitter taste, and is not safe to drink.
It's a stripping run. If you are desperate enough to drink it you need a different hobby :D

Most of the congeners in alcoholic drinks would kill you if you could find a way to drink them concentrated, but without them your finest whiskey would be just another tasteless vodka.