Anyone try dry ice inside a closed loop column?

Rather than adding the ‘dewaxing columns’ to a blasting rig or whatever other method of chilling the extraction, I was curious if anyone simply got everything as cold as possible, and mixed in some dry ice with the plant material?

I am cautious to try it myself just yet, but I’ve been thinking about it… not a huge fan of some of machining on some components of my current BHOgart rig though…

Definitely DO NOT DO THIS!!

The liquid butane will cause the dry ice to sublimate rapidly, and youre going to quickly have a ton of co2 pressurizing your vessel, and if you don’t have a PRV you could have a catastrophic failure


Why don’t you build your self an injection coil? Put a 50 foot roll of stainless tubeing into an ice chest full of dryice. Inject through the coil into the column.


Please don’t build a pressure bomb

Which issue are you trying to overcome? Don’t want to use alcohol? Not getting cold fast enough? Help us pinpoint what you are trying to accomplish and we’ll steer you to a safer option.
Are you trying to chill the material, or solvent, or both?

Dry ice needs to stay vented because it is always sublimating into a gas. It physically expands a LOT in this phase change.

Also I don’t think I’ve ever seen a weld on Bhogart equipment that I remotely approved of, and I don’t know shit about welding…it’s always ugly, with bubbles and blemishes. Back in 2014 I caught them reselling me columns from Glacier Tanks…idiots…


Just to drive this one home.

No. That’s a bomb.


Hi guys, thanks for the replies.

CO2’s rate of sublimation in alcohol or other high boiling solvents is not especially impressive in a short period of time. Especially if the solvent was propane, the bp’s are so close together, I really have alot of trouble believing that a pressure bomb would be created in the quick time blasting lasts. Of course then my solvent would be mixed with co2, didn’t really have a plan for that…

I was simply trying to achieve a very low temp extraction without a different column, but I am not happy with this column anyway. I am considering a design with the wort chiller setup or maybe an inline dewaxing column with it, but really, I am tired of working with gases, so will likely dig deeper into cryogenic pentane or etc. Maybe 80/20 or 50/50 cryo acetone to pentane would do a good job on terpenes

CO2 has no boiling point at atmospheric pressure, and the expansion due to sublimation is pretty severe. Propane can be kept liquid without vapor pressure and/or at static pressure. Dry ice will constantly offgass and steadily pressurize whatever it is contained in.
CO2 gas at 1 atm is 1.98 kg/m^3 while dry ice is roughly 1500 kg/m^3. You’re looking at the vapor being 700-800 times the volume of starting dry ice. Pressure bomb indeed.

Fill the head of the cold solvent vessel with nitrogen gas. Fluids will run from high pressure areas to low pressure areas until equalized. This head pressure will push the liquid solvent out of the dip tube and into your cold, vacuumed material column. Beyond the collection vessel, open a recovery line to a cold, empty, vacuumed recovery tank. This will remove any vapor pressure created in the material column or collection vessel so that you do not see backpressure/equalization and stoppage of flow.

If you’ve ever drained a gasoline tank by blowing air into the drain hose and creating some air pressure at the top, this works by the exact same mechanism.

Nitrogen is not flammable (exactly the opposite) and can be vented back to the atmosphere whenever the solvent is kept cold enough to have no vapor pressure (~ -51°C for propane)

An alternative to nitrogen would be to daisy chain a hot solvent tank to the vapor port on your cold solvent tank. Create the same head pressure using hot solvent (say, 30-40C) in order to force the liquid out of the dip tube.


Gasses can exist as a liquid above their boiling point with positive pressure. Think of a bbq tank, on a 100 degree day you can shake the tank feel liquid. Therefore you could in fact flow room temp solvent over the ice. One thing I found when attempting to use co2 instead of nitrogen in a closed loop was, after burping the co2 off my tanks and turning off the Chiller my pressures would get much higher than normal. The co2 was definitely getting trapped in the tanks when cold. As you know a tank should be cold to burp it, cant burp a warm tank without loosing solvent. I don’t have any way to look into the tanks, my best guesses were carbonation, ice, or liquid would form. This would account for the extra pressure.


Dry ice will still sublimate unless significant pressure is added.

It’s been said a dozen times already but: don’t do this!

Instead: dry ice sleeve your material column, dry ice sleeve your solvent, push solvent with Nitrogen through material column then recover. If you run cold enough, you can skip secondary dewax.

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Yes I know that. I was referring to the butaine or propane in a tank. Later in the text I refered to a situation where I had co2, as a liquid inside my tank. This was from using co2 as an assist gas for injection.

not only is it a bomb ur building but basically a thermobaric bomb.
pressure testing vessels for sc CO2 is the only time i do anything like that

Isnt this the exact sort of reason they dont sell dry ice to people under 18. Cause kids make dry ice bombs. This is a terrible idea. Why cant you just buy jacketed spools and have them sit in a freezer first…then dry ice and acetone will get them cold enough …fast!!


Calm down a bit.


The explosions that plague our industry are created by a fuel air mixture, not a flashack into a tank. The Chain of failure looks like this: leak or rupture leads to pooled gas—>Pooled gas has enough o2 and ignition source----> boom. If you run your machines inside a properly ventilated booth this problem can be mitigated by diluting the leaking gas below explosive limits, and having a sparkless enviroment. Flammable gas monitors should be used to alert the operator.


Someone tried this closed loop?

That is not a closed loop. That is an open blast tube



*Controlled Open Blast

Still your safest option is a closed loop extraction unit and if you REALLY need to go super duper cold and want to keep your tank on dry ice the entire run, then outfit your entire closed loop system or purchase a pre-made pressure tested turnkey system meant for a nitrogen push. ALSO AND FINALLY GET IN PERSON ON-SITE TRAINING!!! PAY FOR TRAINING FOR NITROGEN PUSHES!!!

XD can we also talk about if it wouldn’t explode like a bomb it would surely ruin the product.


I actually know someone who claims they fill Te top head space of material column with dry ice. Didn’t seem to have any problems doing so by the way he described, I told him I’m good without it lol. Yeah be safe. Just get proper equipment to chill your columns.