Passive Butane Extraction & Recovery

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4 responses to this post.

  1. Posted by chemjames on January 3, 2013 at 10:46 AM


    We have spoken a few times over emails, I wanted to ask you about the Appion g5 units, and I just had to return both of mine because I was loosening over % 40 of my butane through the recovery process. I did the test in the G5’s where you close the outline and it builds pressure to 500psi and then shuts off for safety well both my units wouldn’t go over 100psi, so we took them in and they were supposed to have them ready for me this am but when we went to pick them up they said they had to send them back to appion to have them looked at, they told us that we shouldn’t be running n-butane through the units because it ruins the gaskets. So now I’m stumped on what to use to recover my nbutane. Have any ideas that might help to lower the wear and tear on the units using the nbutane? Thanks GW


    • There is little question that Appion has not encouraged butane use, but they seem to be grasping at straws, as to exactly why. The issue we’ve found with the seals on the Appion, has nothing to do with the Butane and has a whole bunch to do with process.

      I fried the upper end of our first Appion the first week we had it, by running it essentially dry, trying to achieve vacuum levels that it isn’t designed to achieve. I rebuilt the upper end, with a $250 seal kit, and we have over 1000 hours on it without incident afterwards, but I also refined our process. We also haven’t had any issues with our second Appion, nor have any of the folks we’ve helped shake out their Mk I’s, II’s or III’s, also using Appions.

      We stop pumping with the Appion, when we reach -22″Hg, and pump off the rest of the butane using the high vacuum pump. The difference between 29.5″ Hg and 22″ Hg, is about 25% of the chamber volume, but at 233:1 ration between n-Butane vapor and liquid, the loss is pennies and the cost of a rebuild kit is usury.


  2. hey gray wolf you are the man. i have a recovery unit like the one DK built all fashioned up and am now debating on what recovery unit to buy promax vs appion and just talked with the appion rep and he said using butane in the machine is a big no no because it could explode if air gets in the system or some static could cause it to explode also. Are there other recovery units designed to handle butane or will i be cool with the ones you guys use thanks


    • If the right mixture of air gets into any system pumping butane, and ignition is provided, it is unsafe.

      What he said about pumping any flammable gas is true, and I can understand why Appion doesn’t want the liability.

      The issue of explosive gas mixtures is why it is important to evacuate the system to minus 29.5″hg to eliminate the free oxygen in the system, before introducing the butane.

      That is why it is also critical that if you do pump some atmosphere into your recovery tank, that you burp it off.

      I can’t recommend a pump for you because of the same liability, only tell you what I picked given the choices.

      I haven’t found a better pump than the Appion, in a size suitable for this application, but continue to look for one. So far all we’ve found are refinery or tank car pumps, which are much too large.

      I invite anyone with information on a better pump selection to share that insight with us’ns and when we find the answer to our prayers, we will share as well.

      n-Butane and Isobutane both have to be handled with respect and care, but are currently being used in refrigeration systems as a more environmentally friendly alternative to fluorocarbons.

      Gasoline is highly inflammable, but we still drive around at high speeds with a tank of it in our cars.

      There are risks associated with extracting with butane, which it why it is critical that anyone doing so, educate themselves and pay close attention to details.

      Even though our Terpenator is a enclosed circuit, we still never use it indoors, just in case something goes wrong, goes wrong, goes wrong, goes…., as mechanical things are sometimes wont to do.

      The indoors Mk II will be pneumatically operated in a 2500cfm exhausted enclosure, to keep any sparks and butane accumulation down, because there is no way to guarantee that there won’t be a leak from a failure, or operator error, despite my best efforts.

      What I did do with material selection, and we can do by regular maintenance and inspection, is minimize risks. That is how airplanes have maintained their safety records, because things go wrong on them as well. A cost of flying……….



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