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Column Freezing
- Thread starter wizzogmb
- Start date
I can almost guarantee that as far as efficiency goes its smartest to just cool your solvent.
introducing warm solvent to a supercold column is less effective than introducing supercold (-40f) solvent over a room temp column.
and then you dont have the column full of di and iso to drain/fill
all just my opinion
introducing warm solvent to a supercold column is less effective than introducing supercold (-40f) solvent over a room temp column.
and then you dont have the column full of di and iso to drain/fill
all just my opinion
^ I agree with that person.
Also, liquid nitrogen is the coldest, cheapest, and most efficient. Not always the most accessible.
Question for y'all with the recirculating chillers. How much power are you consuming running those things? And do you have any maintenance/repair costs to ever factor in?
Also, liquid nitrogen is the coldest, cheapest, and most efficient. Not always the most accessible.
Question for y'all with the recirculating chillers. How much power are you consuming running those things? And do you have any maintenance/repair costs to ever factor in?
Dry ice is CO2.
Dry ice
BTW: I'm surprised I haven't seen anyone trying to make extracts in the Winter months outside in a shed or something.
Where I live you can get -20 C in the Winter and no extra chilling would be required I bet. Think how safe it would be to
make something then.
Dry ice is CO2.
Dry ice
BTW: I'm surprised I haven't seen anyone trying to make extracts in the Winter months outside in a shed or something.
Where I live you can get -20 C in the Winter and no extra chilling would be required I bet. Think how safe it would be to
make something then.
I used snow for about 2 weeks for my solvent recovery tank. It worked so nicely - not as well as powdered dry ice of course.
THanks, thats what i figured, theres just so many chillers and water bath chillers, trying to pick the best for the application.
If sub zero extraction is the goal, you really need to both cool the column and chill the incoming solvent.
The column needs to be cooled for a decent amount of time to allow for the contents to cool as well.
Boiling liquid CO2 in a jacket works very well but the columns need to be designed for it.
The Julabo FP89 doesn't have very much cooling capacity at low temps so it won't have enough excess capacity to cool the incoming solvent. Even the FPW91 will be insufficient for a large extractor.
Depending on the size of the column, just cooling the column will be a waste of time unless the butane is also chilled. The larger the column the longer it takes to draw heat from the center of the column. Pushing warm solvent through a incompletely cooled column won't reduce the wax content.
Having a column initially cooled to -80 is useless if the solvent exiting gets warmed to room temp...
Liquid co2 cooled column and heat exchanger to cool the solvent will give the best results for the investment by far. A system like this needs to be properly engineered taking into account the size of the system and the desired throughput as well as many other factors.
RB
The column needs to be cooled for a decent amount of time to allow for the contents to cool as well.
Boiling liquid CO2 in a jacket works very well but the columns need to be designed for it.
The Julabo FP89 doesn't have very much cooling capacity at low temps so it won't have enough excess capacity to cool the incoming solvent. Even the FPW91 will be insufficient for a large extractor.
Depending on the size of the column, just cooling the column will be a waste of time unless the butane is also chilled. The larger the column the longer it takes to draw heat from the center of the column. Pushing warm solvent through a incompletely cooled column won't reduce the wax content.
Having a column initially cooled to -80 is useless if the solvent exiting gets warmed to room temp...
Liquid co2 cooled column and heat exchanger to cool the solvent will give the best results for the investment by far. A system like this needs to be properly engineered taking into account the size of the system and the desired throughput as well as many other factors.
RB
From the numbers I remember running, it seemed like N2 would be more cost-effective than CO2. I could obviously be mistaken. Human - I am.
What makes you lean towards CO2 over N2? More even cooling? Dewars last longer? Or just cost?
How much CO2 (or N2 if you have your own numbers) do you approximate it would take to cool a 6" x 36' column with a 1" cooling jacket? (Also, feel free to share jacket dimensions on your equipment. Is jacket diameter 2" more than the column OD?
LN2 at -196C will freeze butane. It's probably cheaper but harder to control. A pressure relief valve keeps CO2 liquid.
Calculations... Jeebuz, making me work now.
To cool butane from 25C ambient to -40C will take 160 grams of liquid CO2 per liter of butane. With losses etc count on at least 200g.
Most of the CO2 used to cool the column will be used to cool the metal.
For the same delta (25C ambient to -40C) it will take 60grams of CO2 per kilo of stainless...
The jacket dia. doesn't need to be much bigger than the column. 1" is fine.
RB
I can't get my cold butane to pull into my freezing column without using gravity and flipping my tank upside down. I pull vacuum from jacketed recovery tank with the recovery, dump and input valve on top of my column open. I'm using the mk4c. I cAn pull in 4-5 lbs but j can't get the rest with gravity. Do I need to pull vacuum from the top of my column separate? Please help.
Depends on your mixture and how cold you get it. We use 50/50% mix below about -30C.
We use an auxiliary hot vapor tank if we want more pressure. Hook it to the vapor side of the supply tank and heat it to 100F. It will put head pressure on the cold supply tank, so that it feeds better.
On the Mk IVC/VC's, we use the back end scavenging valve to attach the hot vapor tank. The same valve used to evacuate the rear end of the system between the pump/tank/heat exchanger when shutting down the system.
Respectfully, I see this canard repeated often but as far as i can figure, the contents of most columns doesn't really factor into the equation based on weight and comparative thermal load. As long as the column and solvent are correctly chilled their negative heat capacity will overwhelm any residual heat load within the vegetative contents.
