Passive faster than active?

Youre mistakenly assuming a linear rate of flow with only dT. As less vapor exists less mass transfers. Like I said theres a reason these massive gas compressors exist.

What does the flow rate look like? We’re starting in a vacuum, and with no obstructions assuming unlimited condensation surface area how would that not beat a 27cfm pump. Its like assuming you just open the biggest valve possible and are able to capture it even faster than the rate it would dump to atm because the tank its being condensed into is at vacuum pressures.

Your receiving vessel never achieves vacuum. You can get to zero but no less. And as the pressure differential approaches zero so does mass transfer. Youre basically theorizing a boiler system for vaporization. That runs on a bell curve. Im not just theorizing here ive been operating these scaled systems for years. Passive is good for when you dont want to watch your compressor or have your material pancake at the bottom of the reactor. Set to passive and go to bed. Wake up in the morning and theres still pressure in the system but crude isnt stuck to the reactor. When you wanna go fast you go active. Just dont undersize your compressor.

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I can get my system in the negative without a pump.

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Not negative in absolute but relative. Atmosphere is about 15psi. Jesus guys open a physics book.

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So when my gauge says -10 it’s really not under vacuum?

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yea open it up there wont be a vacuum vs psia, wtf

Lol negative 10 compared to atmospheres 14.7. Im going to have to start charging you guys for this.

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So how much solvent is left in my material column when the gauge is at -10?

4.7 psi.

You understand vacuum is achieved in the absence of gas right? So if you have any liquid with a vapor pressure vacuum isnt possible just relative vacuum to atmosphere.

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well what if we are going to the melting point baby!

Absolute vacuum isn’t possible in the universe. It’s always relative

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why cant the material side of the system be completely dry or liquid free, would it have more to do with the heating of the material side vs the condensing of the recovery side? over time will it not become completely devoid of any butane gas if properly heated and with a recovery side that is colder than its bp? Im still missing something I guess.

We are talking about the pressure or lack there of in a sealed vessel, correct?

also $1000 bucks for a tr21 that take 1.5 - 2.5 hours to recover 25lb run vs a passive system that can do 1 - 6lbs/min I could care less about the couple oz at most per run of butane left over.

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Not true.

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Thank god for entropy eh?

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Now youre getting closer. dT only works if heat transfers. So material in contact with the hts and other mass conducting heat poorly from that same surface. So lower the pressure and it lowers the boiling point! You still wont get all but its a hell of a lot faster.

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yeah id really like to understand this more, specifically why you say you wont get it all, if you could point me in the right direction Id appreciate it. is it some sort of feedback loop of evaporating and condensing do to like gravity or somesuch lol?

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There is matter with vapor pressure in the sealed vessel you speak of. And the focus should be on the pressure differential between high side and low side vessels. Gauge pressure is a reference and unless you set gauge pressure to zero at full vac your zero point is really atmospheric pressure.

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