Automate distilling process

Distillation methods and improvements.

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panikry83
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Re: Automate distilling process

Post by panikry83 »

I fell asleep once at my still when i decided to do a late night run. Nothing happened other than container overflow and getting low wines over the carpet but goddam that's nott a way to wake up I'll tell ya that. Talk about ruining your britches.
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Re: Automate distilling process

Post by Pikey »

I'm just wondering what are the minimum safety sensors one could put on a still, to shut it down automatic in case of an issue ?

Pot Pressure
Ethanol escape
Propane leak
Water Failure
Water too hot
Propane out
Electric Failure (What backup to close valves etc without electric)
Pot temperature
Head temperature

What else ?
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NZChris
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Re: Automate distilling process

Post by NZChris »

Use a latched relay that requires you to manually restart after any shutdown.

Propane should have an NC solenoid valve controlled by the same relay.
Dead man timer that you have to reset.
Condensate temperature can shut the heat off for any condenser water failures. Automating condensate temperature control prevents water loss if the still shuts down for any reason.
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Re: Automate distilling process

Post by WIski »

Pike Wrote;
I'm just wondering what are the minimum safety sensors one could put on a still, to shut it down automatic in case of an issue ?
I'm sure you could put a sensor on "everything" but then the question is, can sensors fail? :shock:

And what Skow said :thumbup:
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Re: Automate distilling process

Post by Bobbywolf »

Yes the sensors can fail. Part of the issue is we use cheap chinesium grade parts for stuff like this because guess what? They are cheap and they work. I used to only have one temp sensor on the takeoff plate of my boka. I've replaced this sensor a couple times now due to it going inaccurate over time.

I have fallen asleep in front of my still before, so I added a temp sensor to the top of my condensor. If the well goes dry or something else to cause vapour to escape, the still shuts down automatically.

Saved me once when I forgot to turn on the cooling flow.

Would I depend on it? No way.
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Re: Automate distilling process

Post by Pikey »

WIski wrote:
Pike Wrote;
I'm just wondering what are the minimum safety sensors one could put on a still, to shut it down automatic in case of an issue ?
I'm sure you could put a sensor on "everything" but then the question is, can sensors fail? :shock:
Of course sensors can and do fail. As NZChris said, the most important single part of any consideration would be to shut down the heating in the event of any issue and there would need to be continuous monitoring of all sensors to ensure the outputs were valid and real. There would also need to be intruder detectors and a non internet connectable computer to run it all. Plus the fuel shutdown and delayed water shutdown would need to operate in the event of any computer malfunction?

And at the end of the day are you building a nice little computerised record of all your nefarious activities ?
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Re: Automate distilling process

Post by speedfreaksteve »

Pikey wrote: And at the end of the day are you building a nice little computerised record of all your nefarious activities ?
We already have this forum to cover that part. :)
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Kareltje
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Re: Automate distilling process

Post by Kareltje »

Pikey wrote:Your gas supply can stop. We had a case in Leicester a good many years ago. However, if it does, it will NOT be restarted - Purge and relight teams at the vvery least would have to visit and reworkk every home prior to letting the gas back on ! :shock:

What makes you thingk your water supply is indestructible ?
Of course, it can happen and seldomly does too.
And if the goverment has any decency, it will prevent an unexpected renewal of the gasflow into the houses. Just imagine what can happen when a whole block would suffer a gasexplosion! :twisted:
I use no water when distilling, so I do not mind that.
Until now I have only used spiral condensers in the air.
So what I do is: start the boiler and watch it till it starts stilling. Then I regulate it so, that the boiling is rather constant and I have a large enough part of the condenser that is cool. Then I place a large enough receptacle and it runs safely.
From that moment onward the system only gets safer by running.
I do not use a pump that needs electricity and water, I only need reliable gassupply.
The very best thing is even: when the alcohol is driven out of the boiler, the heath in the condenser crawls backward and the debit slowly drops.
I still did not really figure out how that works or what the theory is, but it works in my simple potstill configuration.
Automated by sheer physical laws, apperently.
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Kareltje
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Re: Automate distilling process

Post by Kareltje »

skow69 wrote:
Kareltje wrote:To leave the still alone for me is no problem: I have only one uncontrollable part, namely the influx of natural gas from the national grid to my burner. So, when started and properly regulated, my still is as safe as a pan of simmering stew.
That sounds a lot like what the guy said when he set the brakes on that train at Lac Magantic. Problem is, it's not that "only one uncontrollable part" that you are aware of that will screw you. It's the perfect storm of issues that you underestimated, worn parts, acts of god, and that one in a million chance of everything lining up just right or happening at the same instant. That is what will burn your whole downtown business district to the ground. It's always a combination of things, some impossible to anticipate, that make you look back later and say, "Holy shit, what were the odds of THAT happening?"
I do not know about that train at Lac Magantic, but deep down inside me I do indeed agree with you.
But than again: shit sometimes does happen and in the end we are all going to die. Even being there and taking notice will not always prevent disaster or heinous acts of some gods. When you really want to exclude that kinds of risks, you can not act at all.
That is not how I want to live. I calculate the risks as good as I can, I make some tests, think of limits. And indeed: shit can and sometimes will happen. We will see and take it from there.

Edit: I like systems that are fail safe. For example: when you want to keep your feet dry, go live on a hill, not in a polder. Or on terps, not behind dykes. Or in a boat.
Worst thing that could happen to me: I start a spirit run, and just when it starts running I get a heart attack, grab the boiler, topple it over and can not get the gas out. Yeah, that would be a problem. For my neighbours.
Last edited by Kareltje on Mon Mar 13, 2017 3:44 pm, edited 1 time in total.
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Re: Automate distilling process

Post by Kareltje »

NZChris wrote:
AK49ER wrote:Nope don't care what new tech come up , have to be there tending , tweaking , looking , tasting, paying attention to the girl. She needs to be looked at and tweaked that's the fun of it right ? Well I think it is anyhow ...
Most of my stills can be run without any tweaking, so it would be easy to automate shut downs for completion and for faults that you might not notice if you are nodding off in front of the still, a kid has skinned their knees, Ma In Law has picked a fight, you've dropped dead from a heart attack, whatever.
I must admit: I have no system of automated shut down. But the systems I used until now kind of die out by themselves. At the end of a run all the alcohol is driven out of the boiler, the condenser is cool from the start and hardly any liquid is dripping in the receptacle. There is an almost complete reflux and the system is in fact only spilling gas and heating the room.
It could go on for days, in case I got a heart attack. But it will not set the place on fire or cause an explosion.

But I must say: when doing a spirit run I like to pay attention. Just to keep track of what is going on or make cuts.
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Kareltje
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Re: Automate distilling process

Post by Kareltje »

Pikey wrote:I'm just wondering what are the minimum safety sensors one could put on a still, to shut it down automatic in case of an issue ?

Pot Pressure
Ethanol escape
Propane leak
Water Failure
Water too hot
Propane out
Electric Failure (What backup to close valves etc without electric)
Pot temperature
Head temperature

What else ?
Seems you are not looking for minimum, but for maximum sensors.
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Re: Automate distilling process

Post by Pikey »

Kareltje wrote:
Pikey wrote:I'm just wondering what are the minimum safety sensors one could put on a still, to shut it down automatic in case of an issue ?

Pot Pressure
Ethanol escape
Propane leak
Water Failure
Water too hot
Propane out
Electric Failure (What backup to close valves etc without electric)
Pot temperature
Head temperature

What else ?
Seems you are not looking for minimum, but for maximum sensors.
Some would be min, some max - but would ALL need to be proven fail-safe. There are others and this is not an advocacy of automation, just a condsideration of how such a thing might work !

I'm interested to understand how a condensation system without a coolant would work ? :?
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Re: Automate distilling process

Post by Pikey »

Kareltje wrote:
Pikey wrote:Your gas supply can stop. We had a case in Leicester a good many years ago. However, if it does, it will NOT be restarted - Purge and relight teams at the vvery least would have to visit and reworkk every home prior to letting the gas back on ! :shock:

What makes you thingk your water supply is indestructible ?
Of course, it can happen and seldomly does too.
And if the goverment has any decency, it will prevent an unexpected renewal of the gasflow into the houses. Just imagine what can happen when a whole block would suffer a gasexplosion! :twisted:
The reason it would not be turned back on is because the "Dead" pipes will be impregnated with air, which needs to be purged and tested before any attempt is made to relight the system -
Kareltje wrote: I use no water when distilling, so I do not mind that.
Until now I have only used spiral condensers in the air.
So what I do is: start the boiler and watch it till it starts stilling. Then I regulate it so, that the boiling is rather constant and I have a large enough part of the condenser that is cool. Then I place a large enough receptacle and it runs safely.
From that moment onward the system only gets safer by running. .......



.......................... my simple potstill configuration.
Automated by sheer physical laws, apperently.
Sounds bloody scary to me - but I'd love to hear how that works :thumbup:
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Re: Automate distilling process

Post by Kareltje »

Pikey wrote: The reason it would not be turned back on is because the "Dead" pipes will be impregnated with air, which needs to be purged and tested before any attempt is made to relight the system -
I never had a break in the gas supply, but I had my meter changed, some time ago. After that I was told to open some valves to let the air and diluted gas out.
Kareltje wrote: I use no water when distilling, so I do not mind that.
Until now I have only used spiral condensers in the air.
So what I do is: start the boiler and watch it till it starts stilling. Then I regulate it so, that the boiling is rather constant and I have a large enough part of the condenser that is cool. Then I place a large enough receptacle and it runs safely.
From that moment onward the system only gets safer by running. .......

.......................... my simple potstill configuration.
Automated by sheer physical laws, apperently.
Sounds bloody scary to me - but I'd love to hear how that works :thumbup:[/quote]
I am not sure how it works. There is a constant flow of energy into the system so there should be a constant flow of energy out of the system: via the condenser. I tried to make a model of it, but this seems not to work properly.

But in practice it is quite simple.
I had an iron still of 8 litres with an iron riser of 50 cm. Then a copper cooler hanging in the air, with a length of about 4 m and a diameter of 9 mm.
I filled the kettle with a wash of about 12 %BV and some boiling stones, started the fire and waited. When the temperature in the head of the riser was about 80 degr. C I lowered the gas and listened to the rattling of the boiling stones. I regulated the heat so, that the last 3 of the 9 coils of the condenser were cool. Judging by the rattling of the boiling stones and the heat of the condenser I made the system stable.
Then I waited. And by waiting and observing I found that it took about 8 hours to run a stripping run. (I did not think of it that way, 30 years ago.) This ended in a cool condenser and a rather cool head of the riser. Wasted some energy, but no hazards or problems.

So next time I had a stripping run, I started it in the evening, took good care of regulating it and then went to bed.
When I woke up, the head was cool as was the spiral.
A spiritrun needs attention, a singular run needs cutting and attention too. But a simple stripping run needs no attention.

My present still behaves different. I did not see it work for 8 hours without attention. But I leave it alone for some hours, sometimes.
It is not something I advise, let me be clear about that.
But when your equipment is reliable, why not rely on it?
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Re: Automate distilling process

Post by Pikey »

I'm still a bit confused - can you give more detail or a photy please ?
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Re: Automate distilling process

Post by cranky »

Kareltje wrote:But when your equipment is reliable, why not rely on it?
Because it's a proven scientific fact that million to one chances come up nine times out of ten.

Leaks happen, failures happen...basically as has already been said, shit happens. when a leak happens and there is open flame you get what happened to a guy in Oklahoma a few years ago. His garage blew up because he had a system he thought was as reliable as yours and it sprung a leak, blew his garage door off and sent him to jail. That isn't an isolated incident it has happened even to professionals with what would be considered excellent equipment, not just some home made rig.
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Re: Automate distilling process

Post by spiff »

I don't run unattended, except for rare brief periods for this or that. But I trust my still more than I do my clothes dryer. I never run that when I'm not around either.
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Re: Automate distilling process

Post by Kareltje »

Pikey wrote:I'm still a bit confused - can you give more detail or a photy please ?
The system is really the most simple still one can imagine: a heatsource, a boiler, an arm and a very long pipe, spiraled to minimise the needed space.
2014-03-10001a.jpg
On the left my first boiler on the stove, a riser of about 0,5 m high, a head to put the thermometer, a lyne arm and a spiral cooler of 4 m long and 9 mm OD. Do not mind the stuff around it, that is not important.
This is the one I could start, then regulate the gasflow such that a steady boiling was reached with 2/3 of 1/2 of the spiral being hot and the remainder cold. As for leaks: the riser was screwed tight on the boiler and the head on the riser. The couplings from head to arm/cooler were screwed tight too. No leaks there.
2016-04-10-001b.jpg
This is my current still in its smallest form: a copper boiler on a stand on the stove and two bends leading to a spiralled cooler of about 7 m long and 15 mm OD. No leaks at all: the lid is screwed tight on the boiler and all couplings are the normal couplings for water- and gaspipes and can hold in a pressure of 3 bar. And as we all know: there is no pressure in a functioning pot still.

My first still started to leak small drops after some years of use, as the welded seam of the boiler apparently rusted a bit. The drops of course consisted of wash with not more than 10 % alcohol. That poses no real danger.
When I use a new pipe with my current still, it takes 2 or 3 times of use before the couplings are set. Until then they sometimes sweat a bit, but not more than droplets.

As I use ambient air as a coolant I need a long condenser and I have to still slowly. With my first still a stripping run could take as much as 8 hours to finish, so after some repeats I thought I might as well go to sleep during that time.
With my current still a stripping run takes less time, so I can not do that.
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Re: Automate distilling process

Post by Kareltje »

cranky wrote:
Kareltje wrote:But when your equipment is reliable, why not rely on it?
Because it's a proven scientific fact that million to one chances come up nine times out of ten.
No it is not! But I grant you: a million to one may happen tomorrow as well as in a thousand years.
Leaks happen, failures happen...basically as has already been said, shit happens. when a leak happens and there is open flame you get what happened to a guy in Oklahoma a few years ago. His garage blew up because he had a system he thought was as reliable as yours and it sprung a leak, blew his garage door off and sent him to jail. That isn't an isolated incident it has happened even to professionals with what would be considered excellent equipment, not just some home made rig.
If memory serves me well that guy in Oklahoma had done something stupid. But even than you do have a point.
Of course failures happen, but I guess you get in your car almost every day without any hesitation. Sitting on a few gallons of highly flammable stuff, trusting the rusting parts of a very complicated machine and trusting all the other roadusers. And of course you have no enemies who want to kill you by a bomb or cutting your brakes.

It is not like I fill the kettle, light the fire and go away. I take good care to start it until it runs properly. Only when it is running smoothly, I trust it.
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Re: Automate distilling process

Post by Kareltje »

Pikey wrote: Sounds bloody scary to me - but I'd love to hear how that works :thumbup:
Well, I would really like to know how it works.
My observations are quite simple.
I have a pot still like the one in the pictures above.
I fill the kettle with a wash of about 12 %ABV, light the fire, put together the riser, arm and condenser and wait till the vapour rises tothe condenser. Then I lower the fire until the spiral condenser is hot for 1/2 or 2/3 from the start. When the distillate starts to drip I check the fire and keep the heat in the condenser on 1/2 to 2/3. Say 7 out of 10 windings or 5 or 6 out of 9. This ensures that the distillate dripping into the receptacle is cold enough and is not vapourizing into the room. The border between the hot and cold part of the condenser is very clear and quite narrow.
From that moment on I do not touch the valve of the stove, so the flow of energy to the kettle is constant.
One would expect that the amount of energy in the vapour is constant too, so the energy of condensing is constant too. So one would expect the border between hot and cold would stay at the same place.
But it does not: it gradually crawls backward, until it reaches the start of the spiral or the top of the riser.
At the same time the amount of condensed fluid diminishes, until it reaches almost zero.
And of course the strength diminishes too to zero.

Judging by this observations potstilling a simple wash is a self stopping process.
We start with a wash of 12 % and a distillate of 65 % at 100 ml per 10 minutes and we end with a wash of 0 % and a distillate of 0 % at 0,5 ml per 10 minutes.

I can not figure out why the system is coming to a halt. Calculating with vapourizing heat, volume and mass of water and alcohol I find no reason to stop.
Maybe the growing heat loss due to a higher temperature of the wash and the growing empty room over the wash plays some role.

But my observations are the same.
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Re: Automate distilling process

Post by cranky »

Kareltje wrote:If memory serves me well that guy in Oklahoma had done something stupid.
Yes he did something very stupid he took good care to start it until it ran properly. Only when it was running smoothly, he trust it. It then sprung a leak, filled the garage with alcohol vapor and blew up.

and as has been pointed out this thread is quickly becoming about people running unattended which as we continue to say is a bad idea and likely to get this thread locked.

I like the idea of some automation, I would love to be able to put a temperature controlled valve to control the flow of water to my reflux condenser but wouldn't leave it unattended and think such things are beyond my simple understanding of things like that as well as budget.
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Re: Automate distilling process

Post by cranky »

Kareltje wrote:it gradually crawls backward, until it reaches the start of the spiral or the top of the riser.
At the same time the amount of condensed fluid diminishes, until it reaches almost zero.
That's actually exactly what I would expect to happen. As the alcohol in a wash diminishes it requires more heat input to keep the wash boiling at the same rate and less cooling to condense the smaller amount of vapor.

It's a very inefficient system to be honest. You could run much faster if you simply add a cooling source.
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Re: Automate distilling process

Post by Pikey »

did you wind those coils yourself Kareltje ? - They Are lovely ! and such a tiny little pot - is water a huge shortage where you are ?

You could use a pot 5 times that size with just a little water recirculated and cooled. Clearly you're no mug, so why not ? :?
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Re: Automate distilling process

Post by Kareltje »

To be clear: I do not advise to leave your still unattended. Most stills need a lot of attention during running.

I would like to see more about automating stills too, but I felt compelled to answer questions and remarks.
As I now feel I did that sufficiently, I will rest this case.
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Re: Automate distilling process

Post by MichiganCornhusker »

cranky wrote: this thread is quickly becoming about people running unattended which as we continue to say is a bad idea and likely to get this thread locked.
+1
Automation and running a still unattended are two entirely different discussions.
This thread is about automation. Let's stay on topic, no more discussion of unattended stills.
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Re: Automate distilling process

Post by Kareltje »

cranky wrote:
Kareltje wrote:it gradually crawls backward, until it reaches the start of the spiral or the top of the riser.
At the same time the amount of condensed fluid diminishes, until it reaches almost zero.
That's actually exactly what I would expect to happen. As the alcohol in a wash diminishes it requires more heat input to keep the wash boiling at the same rate and less cooling to condense the smaller amount of vapor.

It's a very inefficient system to be honest. You could run much faster if you simply add a cooling source.
Pikey wrote:did you wind those coils yourself Kareltje ? - They Are lovely ! and such a tiny little pot - is water a huge shortage where you are ?

You could use a pot 5 times that size with just a little water recirculated and cooled. Clearly you're no mug, so why not ? :?
I would really like to discuss this further, but as cranky said: maybe this thread is about automation.

@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.

@cranky and Pikey: no I did not wind them myself. I wound a 15 mm pipe of 2 m to a spiral riser, but that was much later. (And I wound a Liebig-cooler as an experiment.)
The 9 mm copper cooler was the heating coil of a geiser, the 15 mm ss cooler I bought as such.

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.)

No Pikey, water is not a problem here. :lol: Not really :twisted:
But the copper spiral weighs almost nothing and air cooling needs no energy. Cooling with water needs valves, hoses, couplings. It implies weight, leakage, attention etc.
When I bought the ss spiral I made a stand for it. Rather than a cooling vessel.
I know I could distill harder and faster, but until now I felt no need to do that.

Maybe later: today I bought a still with a large ginbox and a watercooled Liebig.
And when weather is good, I will start my 80 litr still.
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Re: Automate distilling process

Post by cranky »

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.
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.
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Re: Automate distilling process

Post by The Baker »

Kareltje said, "By cooling you remove and waste the heat you put in the vapourizing of alcohol."

True but you can recover a lot of the energy by using a pre-heater. And I do not yet use grain but some recover hot water to be used in their next ferment.
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Re: Automate distilling process

Post by NZChris »

The Baker wrote:Kareltje said, "By cooling you remove and waste the heat you put in the vapourizing of alcohol."

True but you can recover a lot of the energy by using a pre-heater. And I do not yet use grain but some recover hot water to be used in their next ferment.
Geoff
I do both of those, plus it saves on time and cooling water. Even at hobby scale it's worth doing. On an industrial scale the savings would be huge.
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Re: Automate distilling process

Post by plato »

Pikey wrote:I'm just wondering what are the minimum safety sensors one could put on a still, to shut it down automatic in case of an issue ?

Pot Pressure
Ethanol escape
Propane leak
Water Failure
Water too hot
Propane out
Electric Failure (What backup to close valves etc without electric)
Pot temperature
Head temperature

What else ?

Before I get too carried away in sharing my thoughts here, it might be useful to also share my professional background.

I worked for several decades in the petrochemical industry as a unit controller on distillation units. I also have a trade background in process instrumentation, specialising in process analysers, automated control and critical shutdown systems.

With the benefit of that experience, could I put together an automated system that might be relied on to do a run from start to finish and shut itself down safely when it's appropriate or required (for safety reasons)? Yes...

Would I try?... Nope.

Would I recommend someone without a trade background give it a go?... probably not.

That being said, here's my take on that list:

>>>Pot Pressure
Isn't a reliable indicator that you are safe... and isn't a particularly useful parameter to monitor from a control perspective

>>>Ethanol escape
Whilst ethanol vapours are trivially easy to detect (cheaply) with mass produced sensors, ie)
http://www.ebay.com.au/itm/like/122035679339?chn=ps" onclick="window.open(this.href);return false;" rel="nofollow
My thought is that its a bit like having an alarm to tell you that your horse is out the gate... a bit late at that stage and maybe it would have been wiser to just build a better gate.
... How confident are you going to be regularly testing/calibrating the sensor, versus how confident you would be if you had just got a TIG welded rig using 304 sanitary fittings in the first place.

>>>Propane leak/Propane out
The idea of a naked flame near a distillation column doesn't appeal to me one little bit, especially when the alternative (electric elements) is so easily controllable.

>>>Water Failure/Water too hot
The issue with inferring the system status from water (effluent) temperature is that in the instance of water failure, the water stops moving so is no longer an accurate indicator of what is going on in the column.

>>>Electric Failure (What backup to close valves etc without electric)
It's easy to make an electric element fail safe by using latching solid state relays.

>>>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).

>>>Head temperature.
A moving target... useful to see if the column is puking, and will certainly tell you if the cooling water has failed, but you have to be there watching it to catch it.

So, how I would tackle it would be to set the cooling water flow to get the reflux ratio you want.
Use the cooling water discharge temperature as the setpoint for a PID temperature controller.
The temperature controller would regulate the power to an electric heating element via an SSR.
The SSR would require latching at the start of the run.
The SSR would de-latch via a (high) temperature switch on the pot vapour space.
The SSR would de-latch via a (high) temperature switch on the column head.
The SSR would de-latch via a level switch on the pot.

I'd recommend securing the services of an instrument tech to set it up and tune the PID for you.
best
~c
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