Cryogenic Gylcol Process Chillers for CLS

[tommy_greens]

Looking for an easy way to get cryogenic temperatures during extraction, dewaxing, solvent recovery etc.
I've learned that they are being used by precision on their flagship PX2 or PX1 model.
There are some complaints on their thread though about the power of the chiller that comes with it.

Does any one have a model or a supplier for good quality cryo chillers that gets to -40C and keep up with a heavy load? It would be a dream to find a unit with the power chill multiple locations at the same time and have an adjustable thermostat.

There is a company in India that fabricates them to ones desired specifications but I'm concerned about potential breakdowns and the availability of parts and people that can install them.

http://www.chillersindia.in/cryo-chiller.php

 

[snake11]

I have used thermo scientific and Neslab chillers(not cryo) and never had complaints. I'm sure they have cryo models. I'd stick to a name brand company that you can get parts and service from.

 

[Permacultuure]

Poly science

 

[snake11]

Poly science

I've used poly science as well and never had problems.

 

[Gray Wolf]

The latent heat of vaporization for n-Butane is 165.6 btu/lb, so that converts to about 48.5 Watts per pound:

http://www.engineeringtoolbox.com/butane-d_1415.html
http://www.rapidtables.com/convert/power/BTU_to_Watt.htm

You have to remove both any heat added by the pump, as well as the heat of vaporization to return it to liquid state at about 31.2F.

You can measure the temperature of the gas exiting your pump closely enough for our purposes, measuring the plumbing fitting at the pump discharge with a hand held infrared thermometer.

If you subtract 31.2 from that reading, you will have your delta T for your calculations.

The specific heat of n-Butane is 0.39 btu/lb/F, and can be found in the engineering toolbox link above.

It says that it takes 0.39 btu’s per pound of butane, to raise its temperature 1 degree F.

So if you pump exhaust is 120F, your delta T is 120F – 31.2F= 88 degrees delta T.

Soooo, 1 lb of n-Butane at 88 degrees delta T, requires 88/0.39=225.6 btu to return it to 31.2F.

225.6 btu + 165.6 btu heat of Vaporization = 279.88 btu/lb to remove to return it to liquid state.

Using the converter above, that is about 82W per pound.

We are building our own 10,000 btu/3000W -40C chiller, using a refrigeration plant designed for a -40C walk in cooler, and have the refrigeration plant, the stainless barrel and the stainless chiller coil, but still looking for a circulation pump capable of running at -40C reliably.

So far the magnetic drive pumps that I’ve found are ghastly expensive, so I’ve designed my own air driven one as a last resort. Any of ya’ll know of a good -40C pump that doesn’t cost one arm, leg, and testicle?

As one more thought, check out the properties of a 50/50 mix of Methanol and water. It doesn’t develop the same viscosity issues that glycol develops at subzero temperatures, and actually has good thermal properties.

 

[NorPene Solutions]

Could a 50/50 mix of Methanol and water be placed in a chest freezer or would that pose too high of a safety issue.

 

[A6 Grower]

Could a 50/50 mix of Methanol and water be placed in a chest freezer or would that pose too high of a safety issue.

I have a chest freezer filled with 50/50 glycol and water. Its been working ok. Recently i tossed a few cheapo harbor freight fountain pumps in there to move the glycol around as it was freezing around the edges and top but liquid in the center. Now the whole thing is a nice orange slushy mixture that holds the -10f my freezer gets it to much much longer. Even with a hot lab at 80f my glycol is only at 0f at the end of my 10 hour days. Poor freezer works 24/6 probably. the sides get a little warm to the touch, i'm wondering how long she'll last.

Was pleasantly surprised the little mag driven fountain pumps were able to work as well as they do.

 

[tommy_greens]

Poly science

Dont see a poly sci model that goes to -40.
Have you used one of their chillers successfully to reach cryo temps?

 

[tommy_greens]

The latent heat of vaporization for n-Butane is 165.6 btu/lb, so that converts to about 48.5 Watts per pound:

http://www.engineeringtoolbox.com/butane-d_1415.html
http://www.rapidtables.com/convert/power/BTU_to_Watt.htm

You have to remove both any heat added by the pump, as well as the heat of vaporization to return it to liquid state at about 31.2F.

You can measure the temperature of the gas exiting your pump closely enough for our purposes, measuring the plumbing fitting at the pump discharge with a hand held infrared thermometer.

If you subtract 31.2 from that reading, you will have your delta T for your calculations.

The specific heat of n-Butane is 0.39 btu/lb/F, and can be found in the engineering toolbox link above.

It says that it takes 0.39 btu’s per pound of butane, to raise its temperature 1 degree F.

So if you pump exhaust is 120F, your delta T is 120F – 31.2F= 88 degrees delta T.

Soooo, 1 lb of n-Butane at 88 degrees delta T, requires 88/0.39=225.6 btu to return it to 31.2F.

225.6 btu + 165.6 btu heat of Vaporization = 279.88 btu/lb to remove to return it to liquid state.

Using the converter above, that is about 82W per pound.

We are building our own 10,000 btu/3000W -40C chiller, using a refrigeration plant designed for a -40C walk in cooler, and have the refrigeration plant, the stainless barrel and the stainless chiller coil, but still looking for a circulation pump capable of running at -40C reliably.

So far the magnetic drive pumps that I’ve found are ghastly expensive, so I’ve designed my own air driven one as a last resort. Any of ya’ll know of a good -40C pump that doesn’t cost one arm, leg, and testicle?

As one more thought, check out the properties of a 50/50 mix of Methanol and water. It doesn’t develop the same viscosity issues that glycol develops at subzero temperatures, and actually has good thermal properties.

That is some pretty complex math! If I really dove in i could probably get a pretty accurate idea of the heat load I want to cool though. Thanks for the break down GW!
Would you ever consider buying a unit like this if you were in the market for something off the shelf instead of DIY?
http://farrarscientific.com/index.php?pg=21

 

[Gray Wolf]

That is some pretty complex math! If I really dove in i could probably get a pretty accurate idea of the heat load I want to cool though. Thanks for the break down GW!
Would you ever consider buying a unit like this if you were in the market for something off the shelf instead of DIY?
http://farrarscientific.com/index.php?pg=21

I would sure consider it at the right price.

 

[NorPene Solutions]

I have a chest freezer filled with 50/50 glycol and water. Its been working ok. Recently i tossed a few cheapo harbor freight fountain pumps in there to move the glycol around as it was freezing around the edges and top but liquid in the center. Now the whole thing is a nice orange slushy mixture that holds the -10f my freezer gets it to much much longer. Even with a hot lab at 80f my glycol is only at 0f at the end of my 10 hour days. Poor freezer works 24/6 probably. the sides get a little warm to the touch, i'm wondering how long she'll last.

Was pleasantly surprised the little mag driven fountain pumps were able to work as well as they do.

Are you using the same type of pump for pumping the 50/50 mix to an IC69?

 

[Gray Wolf]

Could a 50/50 mix of Methanol and water be placed in a chest freezer or would that pose too high of a safety issue.

Read link @:http://www.che.sc.edu/faculty/weidner/Sethuraman/MeOH_Solution.pdf

Flammability issues of mixtures:

If you hold a match over pure MeOH in air a fire is likely because the MeOH vapor over the liquid is within the flammability limits.

Looking at the other end if you have 99 per cent water - 1 per cent MeOH by weight and you hold a match over the liquid in air what happens? Nothing I expect.

Question is what happens between 1% and 100% MeOH. Adding to the problem are the different evaporation rates of the MeOH and water....

The following values were used in the calculation,

For Methanol:

Flash point = 12.22 °C
Upper Flammability Temperature = 43 °C
Lower Flammability Temperature = 7 °C
Upper Flammability Limit = 36.5% (by volume)
Lower Flammability Limit = 6 % (by volume)
Ignition Temperature = 350 °C

(Source: The Methanol Institute, Washington, DC 20006 - http://www.methanol.org)

 

[NorPene Solutions]

Link:http://www.che.sc.edu/faculty/weidner/Sethuraman/MeOH_Solution.pdf

Flammability issues of mixtures:

If you hold a match over pure MeOH in air a fire is likely because the MeOH vapor over the liquid is within the flammability limits.

Looking at the other end if you have 99 per cent water - 1 per cent MeOH by weight and you hold a match over the liquid in air what happens? Nothing I expect.

Question is what happens between 1% and 100% MeOH. Adding to the problem are the different evaporation rates of the MeOH and water....

The following values were used in the calculation,

For Methanol:

Flash point = 12.22 °C
Upper Flammability Temperature = 43 °C
Lower Flammability Temperature = 7 °C
Upper Flammability Limit = 36.5% (by volume)
Lower Flammability Limit = 6 % (by volume)
Ignition Temperature = 350 °C

(Source: The Methanol Institute, Washington, DC 20006 - http://www.methanol.org)

Thanks GW!

 

[Permacultuure]

Dont see a poly sci model that goes to -40.
Have you used one of their chillers successfully to reach cryo temps?

http://www.labdepotinc.com/Product_Details~id~825~pid~60529.aspx

Their immersion chillers get down to -80.

I don't have one of their chillers, but Regis does, and has struggled to get it to -40, last I heard.

Recirculating chillers are taxed, domestic made 20l -80c quotes were 30k plus. Across the sea they are about 5k.....

 

[A6 Grower]

Are you using the same type of pump for pumping the 50/50 mix to an IC69?

My coils are IN the freezer thats filled with glycol. Im not pumping the glycol anywhere it stays in the freezer along with 4 coils. The pumps in the freezer just move glycol around to create a more even temp...

I do plan on using one of these pumps next week to pump glycol out of my freezer and through the coil condenser on my rotavap thats coming monday. Ill let you know how that goes.

 

[Dab Strudel]

I have a chest freezer filled with 50/50 glycol and water. Its been working ok. Recently i tossed a few cheapo harbor freight fountain pumps in there to move the glycol around as it was freezing around the edges and top but liquid in the center. Now the whole thing is a nice orange slushy mixture that holds the -10f my freezer gets it to much much longer. Even with a hot lab at 80f my glycol is only at 0f at the end of my 10 hour days. Poor freezer works 24/6 probably. the sides get a little warm to the touch, i'm wondering how long she'll last.

Was pleasantly surprised the little mag driven fountain pumps were able to work as well as they do.

haha id love to try this but back when I had it filled with ice i had to chizzle the ice away to get the tank out once and realllllly dinged the inside of the thin metal. maybe I can flex seal or silicone the holes and proceed with caution... Id drill holes and silicone them to still make the coils self draining :0

 

[Dab Strudel]

Whats the chances Glycol, Methanol, and Water/Ice would be a better mixture?

 

[A6 Grower]

I did the same thing. I just sealed them with epoxy and silicone on top. Works fine unless you made some crazy big holes. And obviously now you have to be careful not to scrape the patch off. Or just spend $600 on a new freezer. I ended up going that route after fixing the holes. Successfully, but the freezer was old and didn't work that great so i got a kenmore elite freezer that goes down to -30F. Gets my glycol down to -10F no problem and holds that for most of the day and gets to about 0f or 10f if it's a long day. I toss some DI in there when its the end of the day and i need some colder solvent but my days go like this, run good stuff first and shitty stuff last. Lots of differnt stuff from differnt people every day. Make the temperature thing not a big deal for me. Im just happy i havent bought ice in months and buy DI every once and a while. And i only need like $20 worth for two or 3 days lol

 

[Oil Crisis]

I tried making a chiller for prechilling my tane before injection. I used a 60/40 blend of glycol/water. I set 8lbs of dry ice in a cooler and pored the solution into the cooler and set my 3/8x 50' coil in it. I was rockin -30 on first injection. I let it soak for 20 mins and dumped. recovered to same rc tank by puttting it on ice with my second coil that was already on ice.
After recovery, I tried to inject again and I ran into some problems, my tane wasnt moving. Was it too cold and could I have froze the butane? I thought butane freezes at -200. I had to take it out of my glycol bath before it would move to the injection port again. What was I doing wrong? I thought that the vapor from the tank should've pushed it though as it did the first time? Is a 30 lb tank too small for vapor assistance? I'm thinking if I get a second 50 lb tank and use that for "warm vapor" and injection and my 30 for recovery would that work?

 

[Gray Wolf]

I tried making a chiller for prechilling my tane before injection. I used a 60/40 blend of glycol/water. I set 8lbs of dry ice in a cooler and pored the solution into the cooler and set my 3/8x 50' coil in it. I was rockin -30 on first injection. I let it soak for 20 mins and dumped. recovered to same rc tank by puttting it on ice with my second coil that was already on ice.
After recovery, I tried to inject again and I ran into some problems, my tane wasnt moving. Was it too cold and could I have froze the butane? I thought butane freezes at -200. I had to take it out of my glycol bath before it would move to the injection port again. What was I doing wrong? I thought that the vapor from the tank should've pushed it though as it did the first time? Is a 30 lb tank too small for vapor assistance? I'm thinking if I get a second 50 lb tank and use that for "warm vapor" and injection and my 30 for recovery would that work?

Water content or too cold will solidify the butane.