Help! Butane always left in material column!

Help! We have a closed loop system built and can not seem to push all of the butane and extract into our collection column. The material column is 8” x 48” chilled down to -75c. We use nitrogen assistance at 30psi to push the butane into our material column. We fill the material column until the material is soaked and fully saturated where the butane/propane is pooled over the material. We have let the material soak and we have run it straight through as well with the same problem. The butane is then pushed from the material column into our collection chamber that has a -25~ inches of Mercury vacuum to start with using nitrogen at 60psi. We let the gas settle for approximately 15 minutes and give it another push. We could do that ten times it seems and still get some more pushed but never seems to fix our end problem. The gas is then purged off and recollected. Our issue is that when we go to pull our material out from the bottom (we are waiting on material socks atm) there has been quite a bit of gas left over, roughly 20 cups worth (filled 2, 10 cup Pyrex dishes) in the filter plates and or material. The last few runs we have left the material in the column overnight and did a final push in the am to recover what was left. The material is cured and going into the column cold and ground up but by no means frozen or even close to a freezing temp. Could the material be holding that much gas in it that we have to wait many hours for it to settle? We have over 1000 lbs to process from the season so freezing it all is a difficult task. Is there a solution we are overlooking? Any and all advice or suggestions are appreciated!!


Heated columns, that’s the one freebie you get from me.

Use the search function, there’s tons of threads about this.


Do you have a crc inline?


We are not running a crc atm

The columns are jacketed, the material column is left cold and our collection chamber is pumped with ice water for collection then heated water for boil off…


Then you just need to either recover more, or write off some losses.

There’s a thread about this exact question

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You will probably want both top and bottom recovery lines, and jacketed columns that you can heat upon recovery.


Heat the columns at a higher temp than the collection, around 140°f. Then flush a few times with n2


You can either heat your column like everyone else says, which is really going to slow you down if you really want that column to be that cold for every injection. Also depends on how many columns you have.

Or once you get socks, drain as much as you can into the collector, pull the wet socks from the top of the column and empty into a secondary heated vessel to recover the rest of your gas.

A tip for draining all the gas out of the sock before pulling from the column. Flush all of the gas through and begin recovery. Leave 25 psi nitrogen in the column. Every 10 minutes, open the valve and dump whatever has drained off the biomass into the recovering collector. Pull the socks just before you reload to inject the next run. Time everything properly for the highest efficiency.


You will never push the LPG out of an 8” packed column with N2, you need to suck it out as a vapor.

Consider venting off the N2 so that only condensable gasses remain in your system, chilling the recovery tank below 50C, and heating the column to 150F


Push it with nitrogen

If you still have liquid solvent left push until you can’t get anymore then hot jacket the material column amd recover from top of column

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Compare pressure between material column and collection vessel. If your recovering and the psi on your collection vessel gets higher than your material column the lower psi wont be able to push into the higher pressured collection vessel. Fill your material column to desired amount, dump inti cillection vessel. Obviously Use N2 to push out solvent if needed. But ince you push out what you feel like was all of it, close bottom feed valve of material column and leave whatever little oressure is still in there. Recover your oil and when collection vessel is beliw 0 go ahead and open material column feed valve and youll notice more solvebt push into coloection vessel. If you run multiple columns repeat process. Last, once the pressure on material columns drop to zero do a final n2/vape assist on xour material column. And push through till you see no more solvebt abd jzst capors oushing through. Recover, collect any remaining oul(shouldn’t be much) and recover the rest off the pressurized gas . Recover all the way opening all bottom valves then bypass valve and recover from top of material columns as well till you rech full vacc again and bleed system, open material columns abd they should ve…dry. I hope that helps dome one. It works for me.

Sorry for the typos.

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After reading this thread I finally broke down and bought some thermostat controlled heat tape. From day one I was never satisfied with the amount of time wasted waiting for the material column to be relatively solvent free and even then there were many times there was still solvent left in the column. I thought many times about a drug store heating pad/bungee cords, a heating mat, or heat tape. That is as far as I ever took it.

This weekend on my second run I was really wanting to be done but once again the material column was cold enough that I knew there had to be solvent left in there. Toward the end of the day I said phuck it, that’s good enough (something I rarely do, but seem to do more the older I get). Sure enough when I was tearing down the machine I found a chit ton of solvent and the mess took longer to clean up than if I had waited for all of the solvent to move through.


BriskHeat Electric Heat Tape with Adjustable Thermostat

Now… how much heat?? 50° 60° 70°… or even 80°

I usually purge at 85° to 90° depending on strain


Careful using electric heat mats. Most aren’t c1d1 rated.

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very good point, might need to cancel that order. And here I thought I had found a simple solution

Briskheat sells c1d1 gas cylinder blankets, IIRC. Those might be a good fit.

I guess the time has come to break down and buy a circulator. It’s strange, I went back over the thread and couldn’t seem to find any of the posts talking about heat mats or heat guns… maybe I was imagining things

Thanks for the input as I would rather be pointed in the right direction than awaiting skin grafts in the ICU … or worse

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Fluid heating is really the best and safest way to go.