I need a small water chiller

OneWithWood · July 10, 2008, 10:56:30 AM

Finally got around to putting a methanol recovery still together to recover the methanol from the glycerine by product of making biodiesel. The still would work much better if I could chill the cooling water circulating in the condensing column. Any ideas?

I do not have running water in the shop currently so I am using a 20 gallon plastic drum filled with water for the resevoir. I put large blocks of ice in the water but I cannot bring the water temp down to a consistant 40°F. So I need to contruct a small chiller similar to a drinking fountain.

flip · July 10, 2008, 11:20:25 AM

Would a drinking fountain work? The barn the mill is in has one that has not been used for a few years but worked when it was on.

OneWithWood · July 10, 2008, 11:23:37 AM

Yes, if the chiller part works that would be just the ticket!

Dave Shepard · July 10, 2008, 11:32:51 AM

Will you be running Meth injection on your diesel vehicles?

Dave

DanG · July 10, 2008, 11:47:52 AM

If you can find someone who is parting out an old motor home, you might find some useful stuff. My old '77 Minnie Winnie has a nice 50 gallon water tank, and a 12v on-demand pump. One of those little refigerators might be the ticket for your chiller, too.

Gary_C · July 10, 2008, 11:52:29 AM

Have you super insulated the drum, particularly on the lower part? Or simply put it inside an old refrigerator with connections thru the side so you can keep the door closed?

scsmith42 · July 10, 2008, 12:50:00 PM

Hey Robert - what about this?

http://www.surpluscenter.com/item.asp?UID=2008071011432763&item=1-1302&catname=electric

You can't beat the price either! I'll pass this link along to Mark as well and ask her what she thinks...

Scott

flip · July 10, 2008, 01:54:56 PM

I'll plug it in this weekend and make sure it works well.

StorminN · July 10, 2008, 05:49:21 PM

OWW,

If you've got a deep freeze... for now, try some colder ice. Get some 1 gallon plastic milk jugs and mix up about 5lbs of salt per 1 gallon of water... make a eutetic saltwater solution. Put these jugs in your deep freeze and turn the freezer down so the temp is as cold as it goes... maybe -10F or hopefully -20F. It will take a while (maybe a day per gallon) for the jugs to freeze, but once they do, and once you take them out and put them in your 20 gallon drum, they will absorb a LOT of heat when they change state from solid ice to liquid saltwater... the difference is, the saltwater will do this at maybe 0F to 10F instead of 32F for tap water... therebye chilling your cooling water nicely.

I have also in the past run a chilled saltwater aquarium... 150 gallon acrylic one that I chilled to about 45F by taking a cheap Costco deep freeze (their smallest one) and putting a 100? foot coil of 3/4"? poly tubing in it (question marks because I can't remember exactly), with a circulator pump that pumped water from the sump of the aquarium, through the coil (in the freezer) and then back. Of course, the only part of this system that was insulated was the freezer itself.

Robert, how big is your gylcerol still? I ask, because the homebrew ones I've been around that were 80 gallons or so just used a small radiator (like a heater core or tranny cooler), and had a couple of pancake fans mounted on them... so no water, just moving air used to cool and distill the methanol...

P.S. I'm not sure if you've tried it or if this will help, but if your glycerol and methanol tanks are made from something that will take pressure (like an old propane tanks) you can pull a vacuum on the tanks and the methanol will boil off a lot sooner, like 100F instead of 180F. Pulling a vacuum (with a small Surplus Center vac pump) takes a lot less energy overall than heating the glycerol an extra 80F and then cooling the methanol...

-Norm.

OneWithWood · July 13, 2008, 09:02:36 AM

Norm,
I am using my old appleseed, a 50 gallon HWH. I load about 40 gallons of glycerol in it, circulate with a pump while heating with the lower element. The element (240v 4500w) is controlled by a pid so it stays constant at the set temp. I have a 'plumbers delight' condensation column mounted to precipitate the methanol. I recently added a schrader valve in the fill/circulating pipe so I can increase air pressure to force the remaining gasses into the column at the end of the process.

I have read about using a vacuum. I have an AC vacuum pump so I can pull any amount of vacuum I would need. Something I have never been clear on is when to open the valve going to the condenser. Currently I leave it open all the time. I assume if I was to pull a slight vacuum (10Hg?) that I would need to leave the valve closed until the unit has been at temp for a period of time. Initially air would enter through the condenser valve. Would I need to add air pressure before cracking the valve. Once the pressure equalized I am assuming the methanol would remain in a gaseous state until condensed. Is that right?

Sometimes the easiest things confuse me :

Fla._Deadheader · July 13, 2008, 10:48:41 AM

Robert, be careful the vacuum doesn't foam the oil and pass the foam into the column.

StorminN · July 13, 2008, 02:20:11 PM

OWW,

I would leave the valve open all the time... and if you were to use a vacuum pump, I would put the vacuum on the methanol recovery tank, not the HWH... with the valve open the whole time... so the vacuum sucks the methanol out, all the way to condensation. I'll try and find a diagram I had and PM you. I'm not sure how much vacuum your HWH will take... it depends on how thick the tank is (if it's older or newer). You'd probably be OK with 10Hg. I know I have collapsed a few different tanks with about 22Hg (he he).

Harold has a very valid point... make sure you've got room above your oil... so maybe 30 gallons in a 50 gallon tank. I'd guess slower would work better (ie. valve open all the time, vacuum pump starts at 0Hg, instead of vacuum tank has 24Hg in it and you open the valve going to the HWH)... of course, this is just a guess.

-Norm.

OneWithWood · July 14, 2008, 08:38:48 AM

So far I seem to not have a foaming problem putting 40 gallons in the 50 gallon HWH (which prolly only has a 48 gallon capacity). My set temps range from a beginning 180°F to 195°F. To date I have run two batches recovering 2.5 gallons of better than 99% pure methanol (measured by weight). I am hoping to recover about 4 gallons. Each 40 gallons of glycerol should contain about 6 gallons of methanol.
If I incorporate a vacuum I will need something better than the 5 gallon fortpak plastic carboy I am using now ;)

Fla._Deadheader · July 14, 2008, 12:34:02 PM

You could be correct with the quantity, BUT, a Vacuum will lower the atmosphere in the processor, and allow the glycerol to expand and create foam.

There was a post about this not long ago, at BioDiesel.infopop. ;)

OneWithWood · July 14, 2008, 07:43:53 PM

Yes, I remember that post. Thanks for the clarification.

Victor · July 14, 2008, 09:56:20 PM

Onewithwood,

Get an old de-humidifier. They are usually available from the dump for free. Carefully re-shape the copper coil on the back of the de-humidifer to fit into the tank of liquid you want to chill. Don't try to empty the freon in the copper coil. Just bend it slowly by hand. Insulate the part of the copper tubing that is outside the liquid to prevent condensation from the air. You can use the 'volume control' knob on the front of the unit as a thermostat.

Victor

flip · July 25, 2008, 07:51:59 AM

Oww,
The water fountain only made slightly cool water, probably not what you need. You are welcome to it but it will probably need to be charged up.

OneWithWood · July 25, 2008, 07:58:16 PM

Thanks for checking it out, Flip. I have the still fairly well dialed in now. It is flowing quite well with just some ice added. I did insulate the drum.