Help with recovery


Hello friends! First post here! Curious if someone could shed some light on my recovery issue… Tried recovering 50lbs of 70/30 butane/propane mix in my newly assembled system last night. 90deg water was circulated through the jacketed base for heat. Active recovery with a trs-21 and a coil packed with dry ice and 70% iso… also had the recovery tank submerged in salty ice water. Seemed to be going smooth at first but ended up taking way too long, aprox. 3.5 hrs! Seemed that the final 25% of recovery took about 1.5 hrs or more… it slowed down a lot! Started to think that maybe it’s counter productive to be icing down the recovery tank while using dry ice and a coil? I know pressure helps turn vapor into liquid and the recovery tank pressure stayed very low the whole time doing it this way. Did I shoot myself in the foot by icing the recovery tank AND using dry ice? Should I just stick to dry ice and not keep the recovery tank in an ice bath? Any other ideas of why this may have taken so long? Any help or tip appreciated! Thanks🙏


50 lbs of gas is a lot to run with a single trs-21


That sounds about right using a trs21 they’re the slowest loudest pump you can really use. You want to keep your recovery tank on ice when you’re distilling into it.


I knew it would be slow with that pump, but DAMN! If the final 1/3 of recovery went at the same pace of the first 2/3 it would have be done in a little over 2 hrs. Is it normal for recovery to drastically slow down as you recovery more of the gas? Or should things stay recovering at the same rate the whole time?


Is your water temperature staying at the same temp?


I have a couple heat exchangers that might help. Check out my post under classifieds.


Water temp was around 90 but climbed over 100 at times. Maybe I let it get too hot?


Well the trs’s run way hot so you put hot vapor into them then it’s going to get even hotter. The issue you are seeing is you are removing vapor with cls’s That’s the idea behind solvent recovery. When you have a chamber of fixed size and consent temperature the liquid gas is going to vaporize at the same rate. More room in collection base+ same vaporization rate means less vapor, this is exhibited by the declining pressure inside of the collection base. With less vapor being compressed into the head room of the base because you gain more as the liquid is turned to vapor means less vapor for the pumps to grab at once causing it to recover slower.


The high pressures are fighting your pump, try n butane much lower pressure. Thats a lot of solvent for a trs21! might want 2-3 for that!


try and … butane much lower pressure? Recover? What’s an appropriate temp for the hot water jacket?


80* f -100*f depending on how fast you want to go/desired outcome. Hotter temps tend to darken hash.


86°F is my golden area 100° is speedy but requires observation.


If ur coil is colder than ur tank than the butane is gonna wanna go to the coil


So a coil with dry ice before my tank that’s just sitting in ice water is counter productive? Am I better off just using dry ice on my recovery tank? Or better yet just using dry ice for everything and forget regular ice? Could solvent be turning back into liquid and be stalling in my coil?


like others have said your fighting vapors with your recovery tank being warmer than you coil. put your recovery tank in a bath of acetone and dry ice. add another coil. and if your not using a molecular sleeve your coils could be freezing water moisture and clogging that . i use to have that problem happen a few times.


I dont have a coil for my recovery I just make sure my recovery tank is covered by dry ice in a 5gal bucket. It works. From what I understand the recovery tank being on dry ice creates its own vacuum because of such low temps.

Hot chases the Cold.


Use regular ice with salt on ur coil…dry ice on ur tank…also if u bleed out the hot vapors out of ur tank it will recover way faster