I have a mostly jacketed 5lb rack mounted closed loop running 100% ntane with nitrogen assist. My jacketed collection vessel is maintained at 120f using 3 sous vide heaters, the solvent tank has both outer jacket and internal coil maintained temp with ice water and submersible pumps. Non jacketed material columns, non jacketed desiccant spool, non jacketed crc spool.
Running a single cmep ol for recovery. 1/2" lines on the entire system. Large condenser coil w/ 1/2" lines ran with dry ice and 99%iso to a slurry consistency
What can i do speed up my recovery? Right now its taking about 4 hours to run 4 pounds
I rock my solvent tank in a dry ice slurry, not sure of the actual temp. But my gut tells If you had a chiller that could keep your solvent tank at -40 you would be able to kill it (as long as you are only running n tane)
Key (at least for my system) is to be able to chill your solvent tank well below your solvents boiling point, pull vac on solvent/recovery tank (preferably empty or atleast most of the way) and start your recovery with your tank at full vac…
With your coil in-line and a chiller for your solvent tank, your tank would stay at full vac the entire time. And your recovery will fucking rip…
If you really want to go wild, add a second 1/2 recovery line and coil…
If my ntane is -40f ill be able to pull vacuum on that vessel without drawing a bunch of butane vapor thru my vacuum pump?
When i loaded the system with solvent for the first time i started my distillation at a -30hg vacuum and finished recovery at -30hg. Then i ran a column and now its pretty much consistently 30-50 psi. I was under the impression as long as ntane is below 32f it should be very low pressure.
So is the jump from -30hg to 30psi because my tank is not cold enough?
You’ve got atmosphere or N2 in your solvent tank if you’ve got pressure at -40C with a nominal “butane only” fill. You pumped it in with your cmep.
Last time this was explored it was as failure to vac down entire system before start. Repeatedly. I’m guessing it’s N2 in your case.
I personally would cut out the ice water on the internal recovery tank coil and outer jacket its probably increasing tank pressure because your coil with dry ice iso slurry should get your solvent much colder than 33F . A single cmep is known to recover about 1/2 a pound a minute on average give or take a little . Second thought maybe there is residual nitrogen built up in the system slowing down recovery trying chilling your solvent below its boiling point and pulling a mild vac -10hg with an properly rated vac pump . The best thing would be to convert to passive hybrid active so start your run passive then finish active to get the last bit .
im guessing you still have a decent amount of nitro in your tank , and if possible switch the coil to ice water and the tank to dry ice and use the coil as your first stage of cooling. Also might need to give that pump some love if it hasnt been rebuilt lately.
You can even go passive without chilling your tank with pretty good results i have experimented with depending on your set up . If you have a secondary pressure vessel and lots of coils loaded with dry ice and iso your solvent entering your tank should be below its boiling point and you can send over any psi in your solvent tank over to your secondary pressure vessel under vac . Just insulate all your coils and tanks with 3 layers of the windshield heat reflective stuff that they sell for your vehicles. When you set up a secondary pressure vessel i have mine set up for distilling gas , taking solvent tank psi , and even eliminating nitrogen with warm vapor push ! I love having it setup like this makes life so much easier. If you have it set up hybrid you just recover as much as you can super fast passive then switch to active . I even use my pump to lower my tank psi by just recovering vapor off the tank and sending it back through the coils since the solvent chills as it evaporates and the liquid coming in is so cold the psi drops to 0 in minutes from 50psi+
I think your onto something, i purged out most of the nitrogen after the collection pot is filled. I will purge it again here in moment. Being that my jacketed solvent tank is atleast 32f i should be able to open up a purge valve all the way open and expell all the nitrogen out of my solvent tank.
Any links to articles that go over nitrogen push n purge youd recommend?
Brand spanking new cmep here only been run 5 times. I dont think the pump is the issue i believe its a temperature issue in the solvent tank or/and residual nitrogen in my solvent tank
When i first starting running this machine i was not utilizing the internal coil or jacket on the solvent tank and had even longer run times 3+ hours per 2.5lbs of material ran. I believe thats around 30lbs of solvent recovered in 3 hours 10lbs solvent per hour. With the jacket in use ive cut it down a bit but ideally im recovering upwards of 30lbs per hour
How is it taking 4 hours for a 5lb run? That seems crazy. How many lbs of Solvent? I run two cmeps and was recovering 1lb every 2-2.5 minutes. Collection totally jacketed and set at 95°. And I had 3/8” hoses so with 1/2” I’d assume that would speed it up a decent bit. Also had my coil in a dry ice slurry like you. Did your cmep always have those recovery rates or has it been slowing down gradually? Kinda thinking there’s just something wrong with your cmep?? People talk so much shit on them for always breaking, ive never had one break. I rebuild them once a year just because they get a lot of use. They don’t like to pull a vac and don’t like to operate over 70 psi, so I just always made sure I didn’t do either of those things as much as possible and my pumps have always been fine. This is my system.
ill get there in a bit, just gotta ask the right questions.