Methods and apparatus for separating gases with ventilated blades

A method for separating an initial gas mixture of different molecular weight gas molecules on the basis of molecular weight of the different components of the mixture, comprising the steps of

• introducing the gas mixture to be separated into a separation zone, rotatably moving at least one curved hydrodynamically smooth porous surface in said separation zone with a relative velocity v.sub.w with respect to said gas mixture under non-turbulent conditions to provide a thin laminar boundary layer of said gas mixture adjacent said hydrodynamically smooth porous surface having a boundary layer displacement thickness .delta..sub.1, to provide an acceleration field having a strength of at least about 1.times.10.sup.5 g immediately adjacent said thin laminar boundary layer, passing heavier molecular weight gas components through said thin laminar boundary layer with a differential sedimentation velocity of different molecular weight components through said thin laminar boundary layer which is largest for the highest molecular weight gas component, such that the highest molecular weight gas component is preferentially concentrated at said hydrodynamically smooth porous surface, and
• conducting gas from immediately adjacent said hydrodynamically smooth porous surface which is preferentially concentrated in the highest molecular weight gas component through said porous surface to produce a separated higher molecular weight gas fraction which is enriched in said heaviest molecular weight gas component with respect to the composition of said initial gas mixture.