Solvent loss

What would be considered an average amount of solvent loss?

for what process? what scale?

Closed loop bho

5lb runs

25lbs in and getting back 14 I’m assuming maybe its a recovery pump leak?

I recently experimented with this. I did 4 runs each one weighing ~22lb w/ fresh frozen material and lost 40L of solvent. So I lost about a half liter per Lb. I’m looking to do some more experimenting with this because I’ve only kept track of this once.

Yeah, that sounds high.

Current shop is loosing 8lb on 100lb wash, and I’m not happy with how much they’re deliberately off gassing to get done.

Will try and get permission to update plumbing. Probably.

Edit: some of that solvent loss is to our pour, and I have uncompiled data on that.

1 Like

Are you heating your material column for recovery? If not you could be throwing away gas everytime you dump material.
Do you have a sniffer to find leaks?


Wouldn’t applying heat allow fats and lipids to trickle back into the oil? I’m running with a sleeved column filled with dry ice and acetone also so we may have to modify the column to allow us to drain before applying a heating jacket as to not heat the acetone

yeah, we have a valve at the top of our system that allows us to close the column from the bottom and scavange off the top of the column and the collection pot.

1 Like

Which is a plumbing mod I shouln’t need to make to a system using 100lb of solvent each run right?

If it’s not done you want to do it! The ability to recover the column seporatly from the collection pot is nice. It also allows you to bake out your column.

1 Like

Could i close my valve and pull the gas put the column passively? Without pump

If I’m understanding right though I would have to heat the column while valve closed undergo collection, with one those heat guns from the explosion video no?

W my biggest runs being a 2x24 would it even give a suffice amount to make the time worth it?

And if staged properly w temps should there even be any left?

Not with a heat gun. Please!

Hot water works well, if you have sleeves you can drain and refill (drain at the bottom is nice…), it’s easy. Otherwise towels soaked in warm/hot water work too.


That sounds a lot better…

Hence the mention of the explosion video lol


What I did with our large sleeved columns (6"×48, 2-8x48) at Burnt River Farms, I would close off bottom ball valves, I stacked a 1.5" BV on another 1.5" BV, release HP clamp between the 2 remove column, cap off the bottom and stand up right in corner with a strap around the column, we then pour boiling water into the sleeve and watch the head gauge pressure,hook up line from column head to recovery pump and recover until pressure on gauge stays around 1-0 psi when pump is off and water is still warm for couple minutes, drain water and empty column, material inside column should be warm all the way to middle and should not have that wet look from solvent remaining. When I run a column that is smaller than 3x36 i run passive, still adding boiling water to Sleeve after my wash is finished, I run a line from the top of column to the liquid port to a chilled solvent tank on dry ice to help the warm vapor condense back to liquid using the cold solvent for assistance, until the column is reading a slight vac


We ran over 200 lbs of solvent (just N-butane) and our loss was under 5 lbs we had days were it would reach 8 to 10 lbs but that was during some diamond experiments


That sounds way more reasonable. And a target to aim for.

Thank you!

1 Like

Any time, I came to the conclusion that wasting solvent is wasting more than the value of solvent but every pound is potentially $500 or more in product made. Saving money for the real money eater…Dry Ice…


What type of recovery pump are you using? You have a chiller-cooler set up leading to the solvent tank? The CMEP-OL have a good volume of piping between the inlet and outlet ports that hold highly compressed gas, along with condensed gas in the chiller cooler.

Ultra basic set up; 2 trs21 pumps, dry ice/ acetone bath, into vacced tank. Been averaging 6 to 10 lbs loss per run recovering out of the column sounds like a good idea, now to convince the boss we need more equipment… YAYYYYYYY!!!:tada::tada:

The solvent could be 1) leaking; 2) in your column of trim 3) in your oil in the pot. For 1) a simple laser gas detector will find the leak, be sure to use on the pumps as well all the way to the solvent tank; 2) heat wrap applied at the recovery stage will burn off the solvent and speed your recovery time; 3) Not sure what your warm water bath situation is, but stainless has poor heat transfer so you could up the temp a bit without burning your oil.

1 Like