John Schilling wrote:
But there's still that pesky "liquify the CO2 under pressure" bit, which
requires refrigerators and compressors, with the moving parts and the
sliding seals, *before* you get rid of the dust. That machinery can
still get torn up if we underestimate the dust problem.

Well.... if you liquefy at ambient pressure at the top
of a column, then off the bottom, on one side,
have the fractional distillation chamber, then you
might get away with not having any exposed seals
or moving parts prior to the stage past the fractional
distillation.

I don't have the relevant CO2 thermodynamics in front
of me at the moment however, so I have no idea whether
it works at 4 millibars and reasonable temps or not.


-george william herbert