Ummm ... it is simple distillation, but I suppose you have to ensure adequate ventilation - assuming that vapors are flammable. It ain’t rocket science ...
I had a distillation business in college, distilling cedar oil for the biology department. Extremely pure cedar oil was used for use with microscopes, as it has excellent refractory properties. Place a drop on a microscope slide over the specimen ...
Made $15/ounce ...
Looks like solvent extraction to me rather than distillation. Using butane as the solvent is hazardous in any case; quite flammable.
I would agree with you...a typical guy with some basic science knowledge and enthusiasm...can run a distillation system in his garage. Course, there are some general rules on ventilation and flames in the garage...which I suspect in this case, were violated. The same is true of safe ways to manufacture meth, which most people refuse to do in a safe manner....and you end up with folks doing in bathtubs and using some lousy sanitation habits.