Butane/ Propane recovery rates

I was wondering if, when you are running a mixed gas of butane and propane in a closed loop, do they recover at the same rate? If you were to recover 100% would the ratio butane/propane remain the same? Would your recover more than the other? Why? How would you know what the recovered ratio was?

you’re doing a fractional distillation. albeit a poorly controlled one. the lower boiling point solvent recovers first. math & some assumptions might get you close.

if you’re using just n-butane and propane, then a reasonable assumption might be that all the weight lost from your solvent tank when you’re done with recovery is butane.

if you’ve got methyl-propane/iso-butane in the mix, the math is more complicated, or the assumptions are more problematic. ie using ideal gas laws and pretending that you’re dealing with ideal gasses.


Firstly, thank you for your reply. Would there be a way to ballpark the ratio off of the tank pressure? Quick and dirty method I know.

yes. that is an appropriate method…and I’ve posted a link to an appropriate resource twice around here. making me wonder why I didn’t suggest that…


I think I’ve seen it and know exactly what you are talking about. Thanks

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I’ll leave it here for anyone else in the future


How fast do you guys recover actively ? How many pumps are you using and what kind of chiller is used in your tek?

I depends on your gas ratio. A mixture with more propane will recover quicker. Two pumps will speed up the process. The Emo Tek I’ve used in the past had no chiller, just the mt69 condenser in ice water. @Apothecary36