Does anyone have any first hand experience using an inline coil with -100c immersion chiller as a means to pre-chill solvent before blasting? BVV specifically sells this setup, which is what I’m referencing (of course this could be accomplished with other brand’s gear): Solvent Injection Kit
Right now I am cooling the jacket the solvent tank to -20c and then using an inline coil with dry-ice to bring the temps down farther before it hits the material. Alternatively, I’m wondering if a setup with an immersion chiller might be effective enough to couple with the cooling system I have already to eliminate the need for dry-ice all-together. I.E. jacket to cool to -20c and then inline through coil/immersion chiller.
Anyone have any real world experience with replacing dry-ice with immersion chiller?
check the kw cooling capacity and you’ll see why noone does this.
edit for the lazy
| Part Number |
P10N4A101B |
| Cooling Capacity @ -100°C (W) |
0 |
| Cooling Capacity @ -80°C (W) |
35 |
| Cooling Capacity @ -65°C (W) |
85 |
| Electrical Requirements (VAC/Hz/Ph/A) |
120/60/1/11.5 |
tens of watts cooling capacity. not the right tool for the job
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Agreed. Dry ice would work much better.
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So the fantasy of eliminating dry-ice from the work-flow remains just that, at least without the use of a large extremely expensive -80* chiller. Bummer.
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Unless you adequately pre-chill your solvent.
Typically, it’s better to put a “big chiller” on your condenser. A low-temperature glycol chiller should go down to -10 or -20C. Check out the Huber CS line for an idea.
Anyways, you pass your evaporated gas through the tubes of a heat exchanger using this chiller on the shell side. If you’re using a butane heavy mix then your butane will be completely condensed and (assuming your evap temp isn’t super high and your heat exchanger is big enough) then the solvent temp only needs enough energy to get down to your desired temp.
So think about it like:
Power required to evap = m*Lf
m is the amount of gas being moved in kg/s
Lf is the heat of vaporization of butane kJ/kg
Power will be given in kW
This is how big your chiller needs to be to condense a flow rate of gas “m”
Power Required to Chill = mCp(T1-T2)
m is the same (kg/s)
Cp is heat capacity in kJ/kg*K
T1-T2 is the change in temperature desired
This is how big your ultra low temp chiller needs to be. So, for example
m = 2.2lbs/min = 1kg/min = 0.0167kg/s
Cp = 2.2 kJ/kg*K
Lf = 386 kJ/kg
T1-T2 = (-20 - (-80)C) = 60C
Condensing Power = 6.43kW
Chilling Power = 2.2kW
Oversized by at least 25%.
Keep in mind:
The power of chillers reduces with temperature.
Heat capacity (Cp) is temperature dependent so this isn’t suuppperr accurate but this is how I’d size a chiller for anyone at this scale. At a larger scale it’s a bit different.
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I have that immersion chiller, it has absolutely no cooling capacity for any kinda heat load. They shouldn’t be selling that for that purpose
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Great write up Phil! Also, keep in mind two things: horsepower required to achieve the same amount of cooling at a lower temperature is higher, and at a higher pressure, latent heat decreases and vice versa. It’s expensive to condense at low temperatures (and thecorresponding low pressure).
4 Likes
Maybe a —40 or a —80 chiller have everything jacketed and set for nitrogen push. Cause you could chill your solvent tank if it was jacketed with a —40 or —80 chiller and then push that thru a column with nitrogen start recovery and have the solvent tank kept at the lowest the chiller can go. Right?
Like manifold your solvent tank and collection at —40 or —80 and then after it’s done extracting you kick in a hot water source
(or maybe set it so you can purge out the chiller refrigerant fluid with an explosion proof vacuum pump or something before you start the warm water recovery, idk I don’t have hvac training correct me if that’s dangerous)
And then just have the manifold closed off and only running the chiller on the solvent tanks jacket. Then start recovery.
In theory sounds like it should work.
Would using an immersion chiller probe in dry ice and solvent mixture like a spd cold trap but rather with a injection coil in dry ice and solvent for a closed loop be beneficial to chill the coil faster and hold at a more consistent cold temperature for injection of the solvent into the material column via nitro push