Butane recovery
I have instructions for extracting pure essential oil from plant material using butane. The problem I have with it is that at the end, the butane is vented. I just don't feel right about venting unburned hydrocarbons into the atmosphere. I've been looking at glass lab equipment (distillation tubes, connectors, etc). I have no background in chemistry, but it seems to me it shouldn't be too difficult to put something together using standard glass lab equipment to capture, distill and reuse the butane.
Butane boils at 31 degrees Fahrenheit and is heavier than air. At the end of the process, the oil is scraped from the bottom of a drying dish.
Does anyone have any suggestions on how to put something like this together?
Thanks
Butane boils at 31 degrees Fahrenheit and is heavier than air. At the end of the process, the oil is scraped from the bottom of a drying dish.
Does anyone have any suggestions on how to put something like this together?
Thanks
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L
But it'll be a few months before I start building a prototype, so I have time to continue searching for ideas.
I've been learning about the different kinds of condenser's, used in laboratory distillation and this looks promising. The set-ups I've looked at were intended for vapor, lighter than air instead of heavier. I still think this is doable.
L
www.chem.leeds.ac.uk
You'll be right, but butane is hazardous, flammable, a bit toxic and probably inclined to "stick" to your extracts (minor problem).
L
On the budget side of things, a coil of copper tubing running through a sealed cup full of the same cooling bath would do well.
As long as you have air (or nitrogen, or whatever gas you feel like using) purging through your flask full of goodies, the butane should collect in a (cooled) recieving flask quite nicely.
I've been looking at different kinds of condensers. The Liebig style are the cheapest. The type I've been looking at the most is the Reflux condensers. They are cheaper than the Dewar condensers and do have a coil through the middle.
The problem is, I don't KNOW which one is right for the job. So what if I go with one that doesn't quite do it? Or buy one that is a lot more expensive than what I need. I'm hoping someone who knows chemistry will see this thread and knows the answer.
The collection flask is another problem. The instructions I've seen for this kind of extraction has you scraping the oil off the bottom of the collection plate with a razor. Difficult to do with a flask.
A new problem I've realized, is getting the recovered butane into a storage container. A small refrigerator pump might do it (from one of those small, dorm type refrigerator might work.
I suggested the dewar condenser because that's what I use in the lab to condense gases and very low-boiling point solvents (like ammonia). It's the simplest to use operationally (no tubes or pumps needed), but they are more expensive than Liebig-type condensers. This one on eBay is pretty cheap, though.
If you go with a Liebig condenser (assuming you've worked out the issues with cooling), all you'll need is the "distillation" flask, a simple still head, a recieving vessel, and the condenser. That's going to be the most inexpensive route.
As far as the product recovery goes, "lab spoons" like this are fairly effective at getting stuff out of round-bottom flasks. How gooey are you expecting the oils to be? If they're destined to be redissolved into something, it might be worth it to just go ahead and rinse the flask out with alcohol or oil or whatever the goo will be ending up in anyway.
It's great to finally meet someone who really knows what they're talking about (you've probably noticed that I don't).
the "distillation" flask
a simple still head
a recieving vessel
and the condenser
This is what I would use with the dewar condenser as well?
I think the lab spoons should do the trick. The end product will be comparable to honey.
Initially, that'll be the end of the process, but I might add additional refining or clarifying later on.
The blue flask contains the butane/oil essential mixture. That's attached to the top of the dewar condenser (red) by a length of rubber tubing. The red liquid indicates where the cooling bath material would go.
As the butane evaporates, it'll condense on the dewar condenser and drip into the receiving flask beneath it, which would also need to be cooled. For safety, the receiving flask should be vented in case the temperature rises and increases the pressure inside the apparatus. I've used a three-neck flask for collection, but any flask that can be vented (two-neck or side-arm/schlenk flask) would work.
Hope this is helpful!
I have a set of plans for a PVC tube (going to use some material other than PVC) where butane is forced in one end, through the plant material, then a filter and out the other into an evaporation plate.
If I use a two-neck flask for the first flask, with that tube connected to one neck and a butane line connected to that.
Then, at the other end I would just need a way to pump the liquid butane into a canister (initially it'll probably be a different canister than the first one to make it easier, but I'm still working on this part).
Thank you!
Now all I have to do is figure out what I need to pump butane (all the systems I'm finding so far are large industrial, but I'm working on it). Anyone have advice on the end of it?
Thanks
. Butane is flammable and explosive. Also a suffocation and frostbite hazard.