Beautiful!!!
What brand of tankless do you use? I wonder if my HC chiller would work?
I have ran i to this in my 100lbs solovent tank there is too much pressure in your tank put on dry ice get it really cold and release preessure out of the gas port should do the trick
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Yea…my buddy doing 5 a min is now at 10lbs a minute on his new bohemiath system. I can pull the first 20 back in like less than 10min. I just need more heat for the other 20 to 30lbs
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So all these times you talk about putting the machine under vac you are referring to using low low temps to create the vacuum?
Is the only time you use a vacuum pump before you start your runs to vac your machine and collection pot etc. ?
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Correct. The only vacuum I have is a venturi pump for pulling vacuum and removing nitrogen from my system.
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I use a smaller tank that I keep empty, that once I have recoved to the point that there is no more liquid gas, I switch to this tank. You want this tank to be chilled as well, it should have a very low pressure. Connect your vapour line to this tank and slowly open valves. When I do this I get the entire system down to about 1-3psi. It’s like a small breath when you open the release valve. Losses are extremely minimal. Then you simply distille the smaller tank back in to your main storage tank.
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Your saying if my solvent tank is cold enough like lets say -10 hg and submerged in dry ice at the point even if there is tane in the tank i can run my regular vacuum pump to get it to lets say -29 hg?
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I’d only recommend doing this if you rock an Welch explosion proof pump just to be on the safe side butane condenses to a liquid state @ -.5C and propane doesn’t condense to a liquid until -44C keep that in mind if you running a blend like most people do, If yah have your tank in that temp range it’s safe to pull vacuum on the tanks
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The exact pump I use is made by Welch the model # is 20198-01 (thermally protected insul class B)
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Easy on these remarks
Pulling a vacuum on a compound is lowering it s boiling point
So yes a safe pump to pull a vacuum is rule number one
And if cooled cryo a vacuum can be pulled but not to hard for the gasses will start to boil
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Do not try to pull -29 hg on a tank with butane in it. It will more than likely boil the butane as the pressure drops…if you pull hard enough…it will vaporize. You burp nitrogen pressure, not by pulling a vacuum over a pool of liquid hydrocarbons…but by burping the pressure…its positive pressure(nitrogen) over a chilled pool of hydrocarbons(liquid). A vacuum pump doesn’t seem necessary here…
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So I usually recovery through the liquid line instead of vapor line so once I’m starting to recover and my tank has been in dry ice -50° I will bleed off excess pressure from my recovery tank which helps assist in my recovery I believe I’m releasing nitrogen and not butane correct and can i just release that till it stops? I usually only slightly open it in like 3-5 second intervals when recovery is becoming really slow … I dont vac my recovery tank prior to recovery since i always have butane in it if that makes a difference
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So, when recovering, valve off the recovery line to the recovery tank. Watch the pressure gauge drop as the remaining butane in vapor form condenses, only takes 10 seconds or so. Now, most the gas in the head space should be nitrogen, as butane would have condensed at -50. Now burp the tank. I do this two or three times to burp the nitro from my collection into my recovery, and from my recovery to the atmosphere. It has worked well for me. Be aware that if working inside, butane fumes can accumulate. Pipe it outside or allow for ventilation.
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You can pull vacuum all you want. You just have to be know how much/little you can pull. How do you think I get my tanks back to a negative pressure for recovery? If you have everything cold enough, the only vapors you will be removing will be the nitrogen.
Using a venturi pump is also ideal for this.
But, you are correct, do not try to pull down to -29. As long as you are cold enough -23/25 is more than enough.
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Keep in mind you are working with PSIG not PSIA on your system gauges and when you vent your tank to 0 PSIG you really still have 14.7 PSIA of nitrogen pressure above the liquid.
If you started your system at -14.7 PSIV (PSI vacuum) or -29" inHg before you applied any N2 assist pressure and now you’re at 0 PSIG after venting, you still have 14.7 PSI that you need to evacuate to get back where you started.
That last bit of pressure will not exit the tank on its own because it’s in equilibrium with atmospheric pressure. This residual pressure will accumulate and begin to hamper recovery in a passive system. That’s why people use vac pumps over pools of liquid butane, which seems like a terrible and avoidable thing to do, IMO.
Also FWIW when you have that vent valve open at 0PSIG, even for a second, there is opportunity for O2 to enter the system which really seems to defeat a large part of why we use closed loop systems in the first place.
When you pull a vac with a pump on that tank you are removing that last bit of N2 and any O2 that may have crept in while you had the valve open. This returns your system to initial pressure conditions.
I think the reason people say to stop a 26 inHG and not to pull a “full” vac of 29 inHg (and to use approved pumps) is because at that point you are close to removing all the excess N2 pressure and you will start to pull significant amounts of butane vapor. You cannot have truly “negative” pressure above a pool of liquid butane.
Again I wonder: Why don’t you simply use warm vapor assist and keep your closed loop system truly closed loop?
IMO, all the venting and vaccing that’s needed for N2 assist slows overall throughput and complicates the SOP compared to an active system with vapor assist where you just use the assist and keep working with no venting or vaccing necessary.
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I’m not experienced enough to know what vac/temp you can safely go to…I’m a redneck in the woods…which is why I specified -29hg.
I am interested now though…I was unaware I can pull a vac on my tank with solvent in it, given the temp is low and the vac level isn’t too low. So if I’ve got my tank in dry ice and acetone, I could safely pull -10 to 15hg safely after venting?
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Ran a couple pounds of material over the weekend. Pulled vac in my solvent tank instead of just burping, but only to about -15hg. I can absolutely fucking rip on recovery now…holy fucking shit. I know I’m uneducated on this shit…having only learned from reading online and my own experience…but that right there is a break through for me. Massive time savings. Thank you for that piece to my puzzle homie. You’ve taught me so much with everything you post. Much respect.
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At that temp and pressure. The only thing you were taking out was the nitrogen. You’re very welcome, man. I’m glad you are doing better with that little tid bit.
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