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Why cold butane is slow rate then room temp butane in a cls ?

dabboy

New member
People like to cold the butane and then extracts for a better result .
But is slow rate compared to room temp butane .
I think the cold butane should flow faster than the room temp butane since the butane is cooler and it's liquid in that form ?
Am i correct ?
 

Gray Wolf

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People like to cold the butane and then extracts for a better result .
But is slow rate compared to room temp butane .
I think the cold butane should flow faster than the room temp butane since the butane is cooler and it's liquid in that form ?
Am i correct ?
Lowering the temperature raises the viscosity, so it flows slower.
 

atomicponderer

New member
People like to cold the butane and then extracts for a better result .
But is slow rate compared to room temp butane .
I think the cold butane should flow faster than the room temp butane since the butane is cooler and it's liquid in that form ?
Am i correct ?

What Graywolf said. Think cold honey vs warm honey.
 
Does anyone have a chart showing butane viscosity at temperature?

Does anyone know what the practical temperature limits are for extraction?
 

MrBungle

Active member
butane acts like freon.... there is a temperature pressure relationship.... the higher the temp the high the pressure... conversely the lower the temperature the lower the pressure

thats why when you take a bottle of butane and release its contents it gets real cold at the point of release cause there is an immediate drop in pressure.....

The reason you can have liquid and gas in a can of butane is cause it was filled under vacuum
 

pnw bb

Member
i think what he is getting at is why do people use cold butane even though its slower. obviously we know that its slower because of its increased viscosity. but i think the valuable information he is looking for is that we like sub zero temps because the solvent becomes more selective at those temps not pulling as many undesirables and water content. warm solvent is much more aggressive. for those looking to make high quality and boutique level extracts the colder the better.
 

Gray Wolf

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i think what he is getting at is why do people use cold butane even though its slower. obviously we know that its slower because of its increased viscosity. but i think the valuable information he is looking for is that we like sub zero temps because the solvent becomes more selective at those temps not pulling as many undesirables and water content. warm solvent is much more aggressive. for those looking to make high quality and boutique level extracts the colder the better.

The key is that the molecules we seek are primarily C-10 through C-22, and the molecules we avoid are C-30. Extracting at low temperatures limits extraction of the C-30 molecules more than it does the lighter ones.

Solly SM, I haven't seen any viscosity charts, but we typically add propane below about -30C and extract down to around -50C with it.
 

Gray Wolf

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Can you explain how the term viscosity applies? butane is a solvent or am i missing something?

Butane is a simple Alkane hydrocarbon whose viscosity changes with temperature. As you chill it, it gets thicker and more viscous, so that at some point it becomes a solid.
 

Sriley28

Member
The key is that the molecules we seek are primarily C-10 through C-22, and the molecules we avoid are C-30. Extracting at low temperatures limits extraction of the C-30 molecules more than it does the lighter ones.

Solly SM, I haven't seen any viscosity charts, but we typically add propane below about -30C and extract down to around -50C with it.

If it's that cold what are you using to get the butane to go to the column? N2 or are you just getting the collection chamber even colder?
 

jswick93

Member
If it's that cold what are you using to get the butane to go to the column? N2 or are you just getting the collection chamber even colder?

They keep the tank in a regular ice bath so it has positive pressure which helps push liquid through the prechiller coil and also use a recovery pump for what is called push/pull assist.
 

Gray Wolf

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If it's that cold what are you using to get the butane to go to the column? N2 or are you just getting the collection chamber even colder?

It works push pull to about -30C after which we use a hot vapor boost.
 

Old Gold

Active member
Thanks for the info! Looks like it's time to upgrade to an active setup

Nitrogen gas will work for the pressure assist as well. With any passive setup, you never want to be dumping into your "final" or "last" chamber. As you fill liquid, the inevitable vapors created need to be removed. If a pump isn't doing this, that is where the cold solvent tank or another vessel comes into play. This is the "pull." Nitrogen or warm solvent vapor would be your "push."
 

Sriley28

Member
Nitrogen gas will work for the pressure assist as well. With any passive setup, you never want to be dumping into your "final" or "last" chamber. As you fill liquid, the inevitable vapors created need to be removed. If a pump isn't doing this, that is where the cold solvent tank or another vessel comes into play. This is the "pull." Nitrogen or warm solvent vapor would be your "push."
With that last vessel, does that have to a certain size based on the size of the run your doing? Also will that have to be recovered or will that just be nitrogen vapor that can be burped out after?
 

jswick93

Member
With that last vessel, does that have to a certain size based on the size of the run your doing? Also will that have to be recovered or will that just be nitrogen vapor that can be burped out after?

It needs to hold enough butane safely for whatever size runs you intend on doing. Also, if you keep the whole tank cold, than a larger tank will have more cold surface area for butane to condense back to a liquid on. Not necessary though. The nitrogen can be burped from your chilled tank after recovery each time.
 

Old Gold

Active member
With that last vessel, does that have to a certain size based on the size of the run your doing? Also will that have to be recovered or will that just be nitrogen vapor that can be burped out after?

You can get away with small - it just needs to big enough and stay cold enough to chill minimal vapors. I typically do use large chambers, because I couple it as a solvent recovery tank separate from my initial solvent feed tank (so equal in size). Also know that the end of the dump will be followed by a column full of nitrogen, so it helps to be able to draw nitrogen into the bigger chambers rather than needing more "vent cycles"; or if only one solvent tank is present, I set it up so that I dump initially into a dewax chamber (same size as collection pot), while pulling the vapors into a cold collection pot. Then I vent the nitrogen from my solvent tank, drain solvent/oil mixture from the dewax chamber to collection pot, and subsequently pull the vapors from collection pot to cold solvent tank.
 

Sriley28

Member
You can get away with small - it just needs to big enough and stay cold enough to chill minimal vapors. I typically do use large chambers, because I couple it as a solvent recovery tank separate from my initial solvent feed tank (so equal in size). Also know that the end of the dump will be followed by a column full of nitrogen, so it helps to be able to draw nitrogen into the bigger chambers rather than needing more "vent cycles"; or if only one solvent tank is present, I set it up so that I dump initially into a dewax chamber (same size as collection pot), while pulling the vapors into a cold collection pot. Then I vent the nitrogen from my solvent tank, drain solvent/oil mixture from the dewax chamber to collection pot, and subsequently pull the vapors from collection pot to cold solvent tank.

I know this is off topic from the thread but for dewqxing do you use something like a Buchner vessel or a collection platter with a pour spout?
 

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