Recirculation chillers and coiled solvent tanks

NorCalHawaii · Mar 13, 2017

Greetings all! I am waiting on a 5 lb rack mounted MK x to be shipped and am trying to figure out the best way to pre-chill the solvent. I want to get the 60# jacketed/coiled solvent tank from Xtractor Depot but i am unsure of which re circulation chiller to order to get -30 solvent. Has anyone had any experience with this application? Specifically i am unsure what size unit (7,15,20,30 liters) will keep the temps down efficiently. Does a bigger resi mean more stable temps and/or is pump volume a factor? I have been considering the Polyscience -40 15/l unit, the ColeParmer -40 15/l unit and a few others but am unsure if they fit the application. Any help would be appreciated, love to hear from anyone that knows....Thanks.

Dabgrow · Mar 13, 2017

I run a 7L/-40 chiller coiled on a 20# and it will only take it to -30 after about 2 hrs. Then again after a run. Need to look at the cooling efficiency at the temp you want to run. My chiller is really only good for 0 to -20, getting from -20 to -30 takes way too long. I'm looking at increasing my solvent tank to 30# and believe I need a 20k Huber to really have it do what I want.

NorCalHawaii · Mar 13, 2017

Dabgrow said:
I run a 7L/-40 chiller .

Mind if i ask which one? Brand?

Gtir · Mar 14, 2017

Coil In a bucket of Dry ice after the solvent tank, don't cool your solvent tank until recovery.

Rickys bong · Mar 14, 2017

The size of the reservoir is irrelevant. The spec you need to look for is the cooling capacity in watts or btu. The chiller should be rated for at least 10 deg C colder than what you want to run.

It all depend on how quickly you want to get to -30 and how much solvent you want in the tank at that time. The more cooling capacity (or ability to remove heat) the quicker you'll get to your setpoint.

RB

Old Gold · Mar 14, 2017

Double check my numbers, but.....Butane for example has a specific heat capacity of about 0.39 BTU/lb*F which means 0.39 BTU is required to change the temperature of 1 lb of butane by 1 degree Celcius. Butane has an enthalpy of vaporization of about 803.26 BTU/lb which means it requires 803.26 BTU to turn 1 lb of butane liquid into vapor (or vice versa).

These are the two stages of heat/energy the chiller needs to overcome, just on the recovery itself. The heat required to cool it to it's boiling/condensing point, and the heat required actually condense it. Add the two together (using appropriate mass and temperatures) and you can appropriately select a chiller to recover with.

1 BTU/hr = 0.293 Watts
3.412 BTU/hr = 1 Watt

.....

I just re-read your post and I completely missed your question. I hope that helps anyways. I'll leave it up for relevance.

As for chilling the solvent before a run, just use the specific heat of butane. There may be minor variation in specific heat values between different phases (liquid vs gas) but I believe it is negligible in this case (unlike water). Could anyone clear this up in case I'm incorrect?

The 60lb solvent tank at Xtractor Depot holds 30lbs of solvent. So, in order to bring 30 lbs of liquid butane down to -30C from 0C:
(30 lbs) x (0.39 BTU/lb*F) (30°C) = 351 BTU

For example, 351 BTU/hr = ~103 Watts
So a chiller with cooling capacity of 103W @ (-30°C) would take one hour to chill 30lbs of butane to -30C.

But like Rickys Bong notes, you might have trouble reaching a true -30C if the chiller is only rated for a minimum temperature of -30C, not colder.

Gray Wolf · Mar 14, 2017

Ditto what RB and OG said.

Besides heat of vaporization, some heat is picked up from the pump itself, and differs pump to pump. One way to tell exactly what temperature it is leaving the pump, is to measure it, using an infra red thermometer on the pump head discharge fitting.

That includes both the specific heat and heat of vaporization. It also changes with flow, because the pump runs cooler with higher gas flow carrying away the heat.

Be careful talking to salesmen, because I repeatedly gave them the specifications and repeatedly got back something else.

For instance, I prefer to only chill the returning LPG to about 0C so that it still flows readily, and use a counter flow at the point of injection to chill it to -30 or 40C using liquid N2.

WolfWurx Mk IVC/VC's used a Haskel EXT-420, which requires about 1500W at 0C capacity to cool its discharge. When I asked for those specs, I continually got 1500W at some other temperature, usually higher.

I also specified a -15C chiller, to maintain the delta T that RB has alluded to.

We ended up using the Temco Fisher Merlin 150 and as RB also noted the btu rejection capacity is the critical factor, not reservoir capacity, because your whole system becomes the reservoir with the liquid in constant circulation through it.

You also have to transfer the heat via the heat exchanger, which is influenced not only by the Delta T, but by residence time and contact area. IE: Residence time at the same flow is less in a 3/8" diameter tube, than a 1/2" tube, because it has to move faster and the contact area is about 33% greater in the 1/2" tube moving at a slower velocity.

The Merlin 150 can't keep up with a VaporHawg using a 20' counterflow heat exchanger, but 50' of 1/2" in an ice bath can, which brings us to length. If you have the heat rejection capacity, you can increase residence time in the heat exchanger, by making it longer.

I advise against double wraps, with one coil inside the other, because it is no longer self draining.

Gray Wolf · Mar 14, 2017

Here is a self draining heat exchanger, which feeds through the side and exits the bottom. The insulation is closed cell foam.

NorCalHawaii · Mar 14, 2017

Thank you guys for the quick and dirty on "chillers". My goal of doing away with dry ice baths and solely relying on chillers might be a pipe dream. I'll do more homework today now that i am armed with some real knowledge. Most of the units i am looking at show stats that aren't really relevant to my application but i am sure if i spend more money i'll get more for it.
Thanks again, i do appreciate the input.

enthalpy713 · Mar 21, 2017

Perrotin-Brunel Thesis

Perrotin-Brunel Thesis

Hey Rickys Bong, I'm unable to obtain anything more than the abstract to the 2011 Perrotin-Brunel paper. Is there any way you can share a copy that includes the methods and results? Looks like a good source of data to help construct some orthogonal experiments.

Old Gold · Mar 31, 2017

Any personal experiences with Across International chillers?

I'm needing roughly 25,000 BTU per recovery. to do this in one hour, I need 7,327 Watts @ 0C - say 7500 Watts to be safe.

Looking at the AI -30C chillers - one with a 30L reservoir; the other with 40L - I want to know if either of these actually perform near their specs. I'm afraid of spending an extra 5k on a chiller (40L reservoir) that hardly works any harder than the 30L.

To specs, the 30L allegedly handles 2800 Watts @ 0C, while the 40L should handle 5000 Watts @ 0C. These would take 2.6 hours and 1.5 hours to recover with, respectively. I definitely find that hour per run worth my time and investment, but I'm not trying to throw 12k at something I could have happily done faster with a little dry ice budget (and without the possibility of equipment failure)....I'm trying to avoid dewar fill-ups at the moment.

I thought about supplementing the chiller's work load with an ice or dry ice heat exchanger prior to the recovery tank, but almost all of the work load comes with actually condensing the butane. It would still help, but not sure how much.

Any help is madly appreciated. AI owners, speak up!

Other recommendations are welcome of course. I'm not 100% set on AI. They just have great availability and reasonable prices. Hooray China!

GonePhishin · May 3, 2017

Hey NorCal,

Did you decide on a chiller yet? I was eyeing the same setup with the Infinity tank and Polyscience chiller. The polyscience website says the -40/15L chiller has a 1000 W chilling capacity @ +20c. Using the formulas provided by OG I think the 15L should work but my math skills are a little suspect. I think I'm going with the 15L since I want to use a jacketed dewax column too.

Gray Wolf · May 3, 2017

Old Gold said:
Any personal experiences with Across International chillers?

I'm needing roughly 25,000 BTU per recovery. to do this in one hour, I need 7,327 Watts @ 0C - say 7500 Watts to be safe.

Looking at the AI -30C chillers - one with a 30L reservoir; the other with 40L - I want to know if either of these actually perform near their specs. I'm afraid of spending an extra 5k on a chiller (40L reservoir) that hardly works any harder than the 30L.

To specs, the 30L allegedly handles 2800 Watts @ 0C, while the 40L should handle 5000 Watts @ 0C. These would take 2.6 hours and 1.5 hours to recover with, respectively. I definitely find that hour per run worth my time and investment, but I'm not trying to throw 12k at something I could have happily done faster with a little dry ice budget (and without the possibility of equipment failure)....I'm trying to avoid dewar fill-ups at the moment.

I thought about supplementing the chiller's work load with an ice or dry ice heat exchanger prior to the recovery tank, but almost all of the work load comes with actually condensing the butane. It would still help, but not sure how much.

Any help is madly appreciated. AI owners, speak up!

Other recommendations are welcome of course. I'm not 100% set on AI. They just have great availability and reasonable prices. Hooray China!

I have zero experience with the AI chiller, but have some thoughts on the general issue.

I previously purchased a 1 1/2 ton -40C refrigeration plant, for a walk in cooler, that was made in USA, but probably assembled out of at least some offshore parts. The project got put on hold and things happened, and I ended up eating the plant, which sits in my garage in the original crate.

I was originally planning to use an expansion valve and a stainless coil in a 30 gallon stainless barrel of coolant, which I could pump too and fro, but alas the price of -40C mag drive coolant pumps is enough to take your breath away.

Consider that for things like pump discharges or pre-chilling injections, a counter flow heat exchanger could be used, with the 404A refrigerant on the jacket side, so that no pump was required.

morbious · May 3, 2017

Gray Wolf said:
Ditto what RB and OG said.

I advise against double wraps, with one coil inside the other, because it is no longer self draining.

Can you please clarify? I thought that "one coil inside the other" IS the type of heat exchanger that you use and have talked about in previous posts?

Gray Wolf · May 3, 2017

morbious said:
Can you please clarify? I thought that "one coil inside the other" IS the type of heat exchanger that you use and have talked about in previous posts?

You are picturing a counter flow heat exchanger.

I was speaking of a single tube with two stacks (rows) of coils, one nestled inside of the other, so that it was no longer self draining.

Breakover · May 5, 2017

Gray Wolf said:
I have zero experience with the AI chiller, but have some thoughts on the general issue.

I previously purchased a 1 1/2 ton -40C refrigeration plant, for a walk in cooler, that was made in USA, but probably assembled out of at least some offshore parts. The project got put on hold and things happened, and I ended up eating the plant, which sits in my garage in the original crate.

I was originally planning to use an expansion valve and a stainless coil in a 30 gallon stainless barrel of coolant, which I could pump too and fro, but alas the price of -40C mag drive coolant pumps is enough to take your breath away.

Consider that for things like pump discharges or pre-chilling injections, a counter flow heat exchanger could be used, with the 404A refrigerant on the jacket side, so that no pump was required.

^This will work! Ask me how I know...

Why use refrigerant (404a)to chill a fluid (dynalene, for example) that you'll pump around to chill another refrigerant (r290, r600/a), when you can just chill one refrigerant with another?

The coil in the infinity coil tanks looks an awful lot like a larger version of the business end of a polyscience immersion chiller often used for cold traps in lieu of dry ice and acetone.

Coincidence??? :biggrin:

HG23 · May 6, 2017

Interesting, can you guys explain how you're using the 404a without a pump? How do you recover it once it has done it's work on the counterflow exchanger?

Breakover · May 7, 2017

HG23 said:
Interesting, can you guys explain how you're using the 404a without a pump? How do you recover it once it has done it's work on the counterflow exchanger?

You definitely need a pump run a 404a system, to pump the 404a.

You'd need an appropriately sized freezer compressor, condenser, txv, and an appropriate sized evaporator of your choice. This evaporator could be an immersed coil, a counterflow coil exchanger, a flat plate exchanger, or even a shell in tube unit. YMMV based upon how you set these up and in what combination, but the principle is the same.

frazierk · Jun 5, 2017

Where did you find that counterflow heat exchanger? I'm looking for something similar.

SkyHighLer · Jun 6, 2017

I found these stainless steel counterflow heat exchangers,

https://www.amazon.com/Kegcos-Stain...ords=counterflow+wort+chiller+stainless+steel

https://www.amazon.com/Stainless-Co...rd_wg=N2GBT&psc=1&refRID=WQFTNC519C4FW3M3RRHC

Gray Wolf has mentioned getting one donated to him that originally came from an Apeks CO2 extractor. More info either side of this post,

https://www.icmag.com/ic/showpost.php?p=6981137&postcount=385

Recirculation chillers and coiled solvent tanks

Member

New member

Member

Member

Member

Active member

A Posse ad Esse. From Possibility to realization.

A Posse ad Esse. From Possibility to realization.

Attachments

Member

New member

Active member

New member

A Posse ad Esse. From Possibility to realization.

New member

Attachments

A Posse ad Esse. From Possibility to realization.

Member

Member

Member

Member

Got me a stone bad Mana