Monday, October 6, 2014

High pressure gas cylinder transfer

I transfer high pressure ethylene gas from a rental cylinder to another cylinder that I own.  I use a cooling water bath to condense the ethylene and transfer as much mass as possible.


  1. Looks like you sourced the Ethylene! Did you get a decent price?

  2. Hey i just ran across your videos and already learned a ton!!! I dont have any background in science i however thought this could apply to when i fill co2 for paint ball. I usually just put 1/2 oz in and release to cool source tank (or just release if a little left in) then i tun 20 lb cylinder upside down ( because its not a siphon tank) and fill 20 oz tank measuring weight off a hanging scale. Should i be using a method more like yours? Is there a reason i shouldnt be transfering as liquid?

    1. Joseph, the critical point of CO2 is about 88*F. Below this temperature, the CO2 will separate into gas/liquid, so turning the cylinder upside down will be helpful since liquid will be transferred. Above the critical temperature, the CO2 will form a continuous supercritical phase in the source tank, so turning it upside-down will not change anything. Of course, as you depressurize, the CO2 will cool itself, possibly below the critical temperature even if the ambient starting point was above. The critical point of ethylene is lower, so the source and receiver tanks would have to be refrigerated first for liquid transfer to be possible.