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pHzero
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Condenser cooling
I've been trying to make some distilled water, but I got stopped by my mum for using up too much tap water for cooling. So I need a new way to cool my
condensers. I'm planning a sort of air-cooling system
The idea is that water is pumped round a closed system, perhaps using one of those drill-powered pumps that I've seen. The hot water goes through some
sort of radiator, perhaps an old car radiator, cooled by fans - either desk fans or computer fans.
Can anyone see any problems with this idea? Is there anything I haven't thought of that I need to take in to consideration
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hissingnoise
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If your water-supply is unmetered it might be easier to convince Mum that your water usage isn't a problem. . .
Failing that, your sketch looks OK but corrosion in car radiators can be a problem. . .
A closed system, though, might side-step that!
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panziandi
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Why not have a bucket of water with some ice added. Place a pond pump in there with a tube leading to your condenser inlet, then a tube leading from
the condenser outlet back to the bucket. Condenser water is rarely warmed much and rapidly cools to a temperature that is usable again, you can do
without the ice for most condensates but for toxic or very volatile/flammable vapours this is recommended. Sacks of ice are dirt cheap and a bucket of
water is much better than a gurgling drain 
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DJF90
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"Sacks of ice are dirt cheap..."
Where the hell do you buy your ice?? I get mine at sainsburys and its on offer atm for £1/2kg... which is still extortionate
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pHzero
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Quote: Originally posted by panziandi  | | Why not have a bucket of water with some ice added. Place a pond pump in there with a tube leading to your condenser inlet, then a tube leading from
the condenser outlet back to the bucket. Condenser water is rarely warmed much and rapidly cools to a temperature that is usable again, you can do
without the ice for most condensates but for toxic or very volatile/flammable vapours this is recommended. Sacks of ice are dirt cheap and a bucket of
water is much better than a gurgling drain |
Hmm, would it cool down enough? I'd imagine that it'd just keep heating up, wouldnt it? And as DJF90 says, ice is pretty expensive. But maybe instead
of using ice, I could chuck some liquid propane in the bucket, which would cool it by evaporation? I'm about to get 19kg of propane for £30, so
that's about 75p/litre.
hissingnoise, sadly, we are metered  We used to be on an unmetered supply but then
my dad got a meter installed to save money
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DJF90
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pHzero - dont be an idiot. Why are you buying so much propane?? Other members have already warned you against buying bulk quantities. You think your
propane is gonna come in a plastic bottle as a liquid? If so you are sadly mistaken. Water by itself will be fine for most things.
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User
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Cooling water does warm up quite quickly , Its underestimated.
I had a bucket with a pump , the system contained about 25 liters of water and yes after distilling for about 2 hours the water felt hand warm.
I came up with a darn simple solution. I bought a 65 liter cement mixing tub.
This keeps cold for hours. By adding a little bleach the water remains free of organisms.
It's a good system which is running fine for more then a year now.
Another funny thing is that i have a timer switch on the pump, when i go to bed and a setup is still cooling down i set the timer on half an hour or
so.
What a fine day for chemistry this is.
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panziandi
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Quite often I just have a bucket with lets say 10L of water in it (actually perhaps 5L) and I have a pump which pumps that through my condenser and
back to the bucket, I can condense most things like that very efficiently. The water cools suffiently travelling back into the bucket and cooling of a
small volume of water by the bulk volume of unused water is adequate, for some things I do opt to have a block of ice added to ensure the water in the
condenser is very cold. Never had any issues at all.
Yeah ice is a bit pricey (compared to tap water) but you don't NEED it, like I said, cooling by mass-action of unused water is suffienent. I suppose
depends how much you are distilling/condensing and over what time period. Try this method before investing in a variety of fans and radiators and time
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DJF90
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I think it would be more important for him to try it before blowing himself up personally... If he's using a heating mantle its risky, but my guess is
our little experimenter here uses a bunsen...
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kclo4
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Perhaps if you need to cool your water to room temperature using the bucket method, you could get a fish air bubbler or something that will pass air
into the water to help cool it off?
It probably wouldn't work very well at all, it was just the first thing I thought of so I decided to blurt it out. But the increased surface area from
the bubbles would lead to increased evaporation, and cooling.
What would probably work a lot better assuming you need it room temperature is to use a metal bucket. That would conduct the heat better into the
cemenet, or whatever it were standing on.
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Ozonelabs
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pHzero- for your own good, don't buy that much propane.
We have no idea how exactly it is that you intend to liquify the propane- surely though, whatever agent you would use to liquify it could just be
employed in itself to cool your condenser? With the added bonus that you dont have to deal with large quantities of flammable material.
You have been warned on more than one occasion about your general laboratory practice. If you ignore these warnings, it will surely be not only to
your peril, but to the peril of the Amateur science community.
Think before you act.
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User
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I can imagine using a large block ice works nicely, I once even thought of using the pool next to my house.
Oke it would be overkill, funny overkill.
personally i really don't like using open flames, only for small scale tests with test tubes.
Djf90 , do you mean the guy talking about the propane?
What a fine day for chemistry this is.
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pHzero
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| Quote: Originally posted by DJF90 | | pHzero - dont be an idiot. Why are you buying so much propane?? Other members have already warned you against buying bulk quantities. You think your
propane is gonna come in a plastic bottle as a liquid? If so you are sadly mistaken. Water by itself will be fine for most things.
|
I've already got through most of a 4.5kg bottle of butane for my bunsen in a couple of months, so I've decided to replace it with a 19kg bottle of
propane - that should last me the best part of a year. It comes as a liquid in a steel cylinder and if you hold it upside down, you can pour it out as
a liquid, because it auto-refrigerates. I tried this with butane and filled a test tube with it then left it boiling away in the sun. When I went back
about 10 minutes later, most of it was still there.
Anyway, back on topic, we have an unused water butt which I think is about 80 litres, I'll try using that. I might try kclo4's bubbler idea - the
increased surface area could be useful. Thanks for your input, everyone!
ps, O3labs, I understand how buying some things in bulk can be dangerous, but propane? Calor gas cylinders are made out of thick steel which can
withstand huge pressures.
[Edited on 14-6-2009 by pHzero]
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watson.fawkes
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| Quote: Originally posted by pHzero | The idea is that water is pumped round a closed system, perhaps using one of those drill-powered pumps that I've seen. The hot water goes through some
sort of radiator, perhaps an old car radiator, cooled by fans - either desk fans or computer fans.
Can anyone see any problems with this idea? Is there anything I haven't thought of that I need to take in to consideration |
Such systems are used commonly; for example, every car has one. The issues are engineering ones.
If you're using ambient air cooling, your cooling fluid won't be as cold as tap water (generally). This means a slight
lowering of the capacity a some given condenser, say, by about one-fourth. If your condenser is running at capacity, you can either buy a bigger
condenser or build a refrigerated cooling loop. For lab scale, a bigger condenser is going to be cheaper.
I wouldn't use a drill as a motor for a drill pump unless your drill is rated for continuous duty (which it's not). Otherwise expect a short
lifetime of that drill. There are plenty of small pumps available, for example, sump pumps or pumps used for water-block cooling in computer systems.
You likely don't need the capacity of a full automotive radiator. A heater core, which is just a tiny radiator, should do you fine.
Box fans such as found on computers work fine. You'll want to fabricate a shroud system so the air flow is actually cooling your radiator off.
You can avoid corrosion in your pumping loop by using automotive antifreeze, which has corrosion inhibitors built in. As a bonus, the maximum
operating temperature of your condenser goes up, should you be distilling fluids other than water.
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1281371269
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I don't see what's wrong with 19Kg propane? It comes in metal containers, 4.5kg, 19kg, 40somethingKg. You can buy a container from a local garage and
it's barely more suspicious or dangerous than buying a few litres of petrol for the lawnmower...
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hissingnoise
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pHzero, DJF90 and Ozonelabs are correct---the propane idea is crazy; a highly flammable gas like propane will cause an inferno at the slightest
opportunity.
The smallest spark will set it off. . .
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pHzero
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| Quote: Originally posted by Mossydie | | I don't see what's wrong with 19Kg propane? It comes in metal containers, 4.5kg, 19kg, 40somethingKg. You can buy a container from a local garage and
it's barely more suspicious or dangerous than buying a few litres of petrol for the lawnmower... |
Yup, in fact it comes in steel bullets and boils a lot quicker if it did leak/explode, so you could consider it even to be safer. I know plenty of
people who use big bottles of propane for camping, but have never managed to kill themselves
| Quote: Originally posted by hissingnoise | pHzero, DJF90 and Ozonelabs are correct---the propane idea is crazy; a highly flammable gas like propane will cause an inferno at the slightest
opportunity.
The smallest spark will set it off. . . |
I take it you didnt mean to include me in that list? xD
But yeah, now I come to think of it, its pretty damn easy to ignite - that wasn't one of my best ideas.
[Edited on 14-6-2009 by pHzero]
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User
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This gets me thinking, what is the max use able temp for a condenser cooled with water.
I can imagine there would be a point at which the thermo shock would be to great for the glass to handle.
If course this could be slightly avoided by placed the condenser far away from the heat source, where one could use a bridge.
Anyone?
What a fine day for chemistry this is.
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Lambda-Eyde
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User: That's why one uses air condensers for substances with a BP of ~200*C and higher.
But yes, it is an interesting question.
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pHzero
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| Quote: Originally posted by User | This gets me thinking, what is the max use able temp for a condenser cooled with water.
I can imagine there would be a point at which the thermo shock would be to great for the glass to handle.
If course this could be slightly avoided by placed the condenser far away from the heat source, where one could use a bridge.
Anyone? |
Hmm, thats a good question. I'd say at least a few hundred degrees - i poured cold water in a borosilicate beaker of molten sulfur once and it came
out fine. But on the other hand, a few days ago, I left a melt of Ag2O to freeze in a borosilicate beaker, just being cooled by the ambient air, and
it broke.
[Edited on 14-6-2009 by pHzero]
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merrlin
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If you are doing this outdoors, then the closed loop system you suggest could be augmented with a water mist applied to the radiator. Evaporative
cooling would allow a compact radiator and reduced water consumption. You should use enough mist so that the excess water collects and drips off the
radiator, preventing mineral buildup. From an energy balance standpoint, the heat removed from your condensate will be largely used to evaporate a
similar quantity of water from the radiator surface. Ice would be effective, but the enthalpy of fusion (6.01 kJ/mol) is quite a bit less than the
enthalpy of vaporization (40.68 kJ/mol).
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DJF90
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Its not the fact pHzero is buying 19kg of propane that bothers me. Its his irresponsibility and intended use that does. Butane will stay liquid when
you empty a container of compressed (liquid) butane because the bp. of butane is only -0.5C. This is doable just using a salt ice bath. Propane I
suspect is another matter, and I have a funny feeling that you'll have trouble getting it out in liquid form (in a usable amount).
Rather than have you blow yourself up with the bunsen, I suggest you invest in a flashback regulator, just in case... 19kg of propane + flame does not
sound like much fun. Make sure that its a propane regulator, and that it fits the bottle properly... this isnt something you want to bodge.
And a water cooled condenser should only be used for components boiling below 150C from what I've read... although I've used a liebig with flowing
water to distill oil of wintergreen, bpt 220C. I wouldnt do this often though because its bound to cause some stress in the glass which will
eventually lead to breakage.
[Edited on 14-6-2009 by DJF90]
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pHzero
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| Quote: Originally posted by DJF90 | Its not the fact pHzero is buying 19kg of propane that bothers me. Its his irresponsibility and intended use that does. Butane will stay liquid when
you empty a container of compressed (liquid) butane because the bp. of butane is only -0.5C. This is doable just using a salt ice bath. Propane I
suspect is another matter, and I have a funny feeling that you'll have trouble getting it out in liquid form (in a usable amount).
Rather than have you blow yourself up with the bunsen, I suggest you invest in a flashback regulator, just in case... 19kg of propane + flame does not
sound like much fun. Make sure that its a propane regulator, and that it fits the bottle properly... this isnt something you want to bodge.
|
I saw it work on TV - it was a program my younger brother was watching where they had to make a beer cooler. They turned a propane bottle upside down
and used liquid propane as a coolant. But now I see that it wouldnt really work if i'm using a bunsen nearby. It'd just go up in flames. I've got a
suitable regulator, and I think its designed to prevent flashback - if you blow through it backwards, it closes a valve.
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entropy51
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pHzero, why are you distilling water of all things? I buy distilled water for less than $1 a gallon and I use it for many sensitive analyses without
problems.
You can use a pump in a large bucket of water, as has been suggested. When the water starts to get warm, move the condenser outlet hose to an empty
bucket and take out most of the water. Dump the warm water, bring back a bucket of cold water and dump that into the bucket with the pump.
Condenser water only needs to be about 20 or 30 degrees cooler than the the boiling point of the distillate. I only use ice water for distilling when
the boiling point is less than 80 degrees or so.
There are probably limits on the amounts of flammables your fire code allows to be stored in dwellings. If you have a fire, the fire marshall's
report will note that you were in violation of the fire code. Guess what? Your Mum's insurance company will not pay off on the policy!
Personally I am beginning to believe that pHzero is concocting wild tales of dangerous plans just to set us off. Even most kewls have better
sense.
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watson.fawkes
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Propane is a refrigerant,
designated R-290. So of course expanding a liquid refrigerant causes cooling. The problem (danger aside) is that it's a horribly, horribly inefficient
use of refrigerant.
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