I’m only 10 or so runs into using a nitrogen push and it’s caused me to have a slew of questions. Not asking for a spoon fellas I’ve searched nitrogen on here and read everything and I still have questions. For reference I’m running a 1lb vertical CLS.
I’ve noticed if I leave some pressure when recovering it does not ‘bubble’ up to my lid as fast and I can leave my recovery valves wide open. Previous to nitrogen since my solvent tank is in iso/di it normally will recover at very close to 0psi, but I can not open both valves (liquid and vapor port) until half way through recovery or it will bubble right to the hemispherical lid. Is this safe to leave some pressure as long as I just bleed off the pressure from my solvent tank and system post recovery?
Does it matter if solvent bubbles to the lid? it seems like there is always a cushion of gas that prevents it from sucking liquid straight into the solvent tank.
If I leave pressure in my collection won’t this increase the evaporation temp for terps helping me preserve more terpenes?
I’ve noticed I am losing more solvent per run since adding nitrogen. The mass of solvent moves faster to collection but the material is staying wetter and i’m losing about .5lbs more solvent (1lb runs). I can’t think of any relation to nitrogen but it’s the only change. I’ve experienced this solvent loss both when bleeding off the pressure prior to recovery and with some pressure left in recovery. Recovery is in iso/di, solvent tank starts in iso/di but I remove it when I begin the process (to monitor weight), material column is sleeved and I’ve ran both with the sleeve empty and full of di and the temp difference seem to not matter. The top ¼ of the material column will be bone dry but near the bottom it’s still wet. Should I just sit and wait longer after I haven’t seen any movement in the collection pot for more gases to pass through the material?
Because pressure scares me (I have PVRs everywhere) I only ‘burp’ nitrogen into my solvent tank. Should I just leave the nitrogen on at my set psi (40) until all solvent has moved through the system? Does this make a difference besides the ease of mind I have knowing the nitrogen regulator can not ‘run away’ on me?
Thanks fellas for those that are helpful I’m offering free hugs.
For some background, I run a large 150 lb industrial butane system (actually currently running right this second, I’m waiting on my butane recovery). Hopefully I can answer some of your questions.
Before every run, we pull vacuum (-10ish psig) on every column and check for leaks. As long as your seals and clamps are all tight and you’re not leaking anywhere, a few psi of pressure is perfectly fine. IDK if your equipment is ASME stamped or anything, but even if it isn’t 10-20 psi isn’t that dangerous as long as you’ve checked everything beforehand and made sure there’s no leaks.
Solvent bubbling back into the solvent tank isn’t a problem, but crude is. If it’s come in contact with plant material, you don’t want that backflowing into your solvent tank.
Yes in theory, but butane boils at such a low temperature anyway, your terpenes will be preserved pretty well no matter what. I personally haven’t experienced much difference in the terpene content for runs collected at pressure.
It’s always extremely difficult and/or time consuming to recover butane held up in your plant material. My best theory is that the nitrogen assist causes your bulk liquid to move to collection faster but doesn’t help the held up butane to move. The held-up butane will move through at a fixed rate and when you’re not using nitrogen you give it more time to naturally pull through as opposed to the fast transfer with nitrogen. That’s my best guess.
Setting your regulator to a safe pressure is a very prudent thing to do, considering some of those nitrogen tanks can be pressurized to 100’s of psi. My first job out of school was doing relief valve sizing and analysis for big oil refineries. #1 rule of process safety when it comes to pressure is to just design an inherently safe system instead of relying on safeties if something does happen. This means it’s easier to simply limit your source pressures to keep things safe than to rely on PSVs to keep you safe.
Have you tried recovering off the top of your column after your done recovering the pot? I usually do this to scavenge a lil extra tane but truthfully never even weigh how much I get from the columns
Nitrogen assist works on the principle of a pressure gradient. Essentially when you start there is a high pressure at the upstream end and a low pressure at the downstream end. Your solvent acts as a plug and is caught in the middle, so it is ‘assisted’ through. Oce the majority of the solvent is pushed through, it’s likely that some piping/communication occurs between the upstream end and the downstream end. No longer impeded by the plug flow, the pressures equalize and the gradient drops to zero. You can try to isolate the flow by directing to a secondary collection vessel so that you can reestablish a gradient to try and recover more solvent. Will burn a lot of N2 with bypass going this route.
Leak checks shouldn’t be done with negative pressure. Those seals are designed for positive pressure. Pressure checks should step increase to the max operating pressure and hold for x minutes.
Are you using jacketed columns? What temps do you run at? Are you stalling in a dewax column? What is your process?
I made a purge manifold plumbed to the outside,
With ports on all vessels, , I just burp off n2 to keep pressures lower, my 2lb system seems to work better that way.
I don’t use as much n2 as some, I push 10lbs if solvent with under 20psi
I should clarify. We positive pressure check after every major disassembly or cleanout at regular intervals. Our day to day checks are at vacuum and more intended to be a sanity check in case someone didn’t tighten a clamp or close a valve or something of the sort.
sleeved column. i wont lie and say i check temps every run because i dont. I do keep solvent in di/iso slurry for at least an hour, material column is sleeved and is filled with di, material is in freezer prior. collection is in iso/di as well. Stall is anywhere from 15 min to 1 hour depending on what kind of time i have avialable and how much mat
sleeved material column filled with di,di/iso slurry for at least 1 hour on solvent and recovery (not monitoring temp but based on conditions -40+ cold). hose on a valve on recovery that i purge to outside. I need to make a manifold that allows me to run nitrogen and a recovery line to solvent tank. for now i run nitrogen line to vapor port and at the beginning of recovery i purge both lines of air before fully tightening on solvent tank end then open valves.
if the added pressure doesn’t increase your boiling point beyond where you’d like to be and it makes your system behave better keep it up.
try to keep extract out of your recovery lines.
what temperature do you recover at? as long as there is liquid solvent remaining your extract does not exceed the solvent’s boiling point. just dont dry boil your extract.
to actually get all the solvent back you need to add heat to your plant.
40psi is tame. keep doing what you’re doing if it works.
hey man so what would you do if you collected butane in your collection base and it was a vapor and looked gaseous instead of a heavy flow i have my jacketes base heated to 100 and i have my cooling coil in dry ice as well as my lp tank but im reading positive pressure on my guages
