Im in the process of trying to go passive as well. I read that part about vaccing down after nitrogen assist can you expand more on that and how you did it? I want to try but it makes me nervous using a vac while the system has a bunch of butane moving around. If your solvent tank was on DI does that mean there wasn’t much pressure to vac down anyways? Im just trying to picture it.
I have the ability to do any size up to 2" from my collection but my coil is a 1/4" and the solvent tanks im using are 3/8 valves at max.
It sounds like this is the way to go so I really want to go passive!
Curious I just looked up what a sieve is and apparantly it’s an alumina silicate and isnt activated alumina also that? And I’ve heard that silica gel and activated alumina are both desiccants so my question is would running aa and silica in a crc remove the need for a sieve?
Interesting. I wonder if anyone could give a detailed explanation of this I would live to hear it and I am curious if such little but if moister would pose a problem without a sieve as it would be filter out the next run. Maybe if the tank is going to sit for awhile sieve and store?
The sieve is filled with beads used to take moisture out of the solvent on the way back to the solvent tank. You can use it without one but then you contaminate your tanks.
I was curious about vacing down while the system is running to get that vacuum in the solvent tank.
It is done. But you need to watch the vapor pressure. You can hear and see on the gauge when you start pulling butane vapor. You need to have the collection cold so the butane is wanting to be under vacuum without changing phase.
Is it safe with a standard vacuum pump? Probably not. Do I do it…absolutely.
So I was gonna take a shot as passive next run and I have 2 solvent tanks I was gonna put on DI. I should also have the collection on DI? I have nitrogen assist as well. So I run everything through into collection then vac down the solvent tanks then open up the recovery line?
Im gonna try it ill just make sure to be careful and watch my guages!
I think you missed the point of my post… the beads in the sieve are alumina silicate (or activated alumina) so my point is crc has activated alumina and silica gel is also a desiccant ( a hygroscopic substance used as a drying agent) so a case can be made that crc will remove moister from the solvent ?
It makes sense thinking about it like that im curious if it might help a little bit.
I would assume the sieves wouldn’t really be used as much if the crc acted like a sieve itself and I know most guys on here run a sieve or filter dryer no matter what.
I would suggest against leaving your media to act as the desiccant for your solvent. There is a reason why so many people bake their media. Unwanted moisture can add a slurry of different problems during your run and generally locks up your filter stack.
Dealing with a mol sieve will save you a ton of headaches IMO.
Plus beads be cheap
certainly won’t work for the “I don’t bake my powders” crowd…
as far as vac/ing N2 out of your solvent tanks, to do that safely the best solution is a N2 permeable membrane. see Tricks of the trade - #124 by Soxhlet (I suggest reading the whole thread. all kinds of gold in there…)
Nice. I switched my recovery to passive as well using a 3/8" line and 3/8" condensing coil. The reason I was asking is my solvent tank is a welded 1/4" fitting so I was worried about a bottle neck at that point. I’m def. recovering faster then my Cmep with 1/4" lines. I’m waiting on a couple things in the mail as soon as the come I will have dual 3/8" lines with dual coils. I’m hoping this really speeds things up.
Since the switch though I’ve been running into a new problem. I have one line that has been clogging even with 60psi of pressure behind it (nitrogen). I’ve checked all my hoses and ball valves they all seem to be free of debris. The only thing I can think of is water in my lines freezing now that im running everything so cold. Only thing that trips me out is it’s only happening to one spool, and not the other.
@Hansel Do you think the dual 3/8" lines will recover as or near as fast as a 1/2" line?
The ID of hoses vary a decent bit, so it’s hard to say without hoses in hand which will have a larger vapor path.
After going from 3/8 to 1/2 on my recovery side…I will slowly up my injection side to 1/2 as well. I believe when going to bigger colums, more flow upon injection will aid in a thorough extraction.
