You need to understand the flow physics pumping/sucking the low density butane causes choking in the orifice of the pump (from supersonic flow).
These issues are best explained in two of my insta posts:
https://www.instagram.com/p/B4ZTOKch4Vl/
https://www.instagram.com/p/B4ZPTjJBT2l/
Hence why I am a proponent of using passive for everything, even large scale.
If you take a look at the specs of the systems we offer you will see the electric refrigeration is hugely more cost effective than CO2/LN2, and provides all the needed energy to pre-chill the solvent and do recovery (3 loops total on our flagship model: https://www.greenprocess.solutions/2020/01/13/2-5-4-ton-refrigeration-system-spec-sheet-quote/).
The extractor needs to correctly designed for all of this to work, obviously.