NOVELTY - Gas separation method for separating carbon dioxide from a gas mixture comprising methane and carbon dioxide, comprises utilizing a rapid cycle kinetic pressure swing adsorption apparatus comprising an adsorbent structure, where the adsorbent structure comprises a kinetic adsorbent comprising a molecular sieve with an average pore size less than 3.9 Angstrom .    USE - The method is useful for separating carbon dioxide from a gas mixture comprising methane and carbon dioxide.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a pressure swing process cycle for separating carbon dioxide from a gas mixture comprises methane and carbon dioxide, comprising: (a) providing the gas separation device; (b) introducing the gas mixture at an elevated pressure to the adsorbent structure whereby carbon dioxide is preferentially kinetically adsorbed by the adsorbent to produce a methane-rich product gas; (c) delivering the methane-rich product gas from the apparatus; (d) reducing the pressure in the apparatus whereby the adsorbed carbon dioxide is desorbed from the adsorbent to produce a carbon-dioxide-rich exhaust gas; (e) delivering the carbon-dioxide-rich exhaust gas from the apparatus; and (f) repeating steps (b)-(e) in a rapid cycle with cycle speeds of 2-30 cycles/minute; and    (2) making an adsorbent structure for a pressure swing adsorption apparatus where the adsorbent structure comprises an adsorbent sensitive to sudden increases or decreases in water content, comprising: preparing a slurry of the sensitive adsorbent and water; coating a substrate with the aqueous slurry; and drying the coated substrate to produce the adsorbent structure where the drying comprises first, second and third drying stages in sequence, where the rate of drying in the second drying stage is slower than that in the first drying stage and the rate of drying in the first drying stage is slower than that in the third drying stage.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of one pressure swing of rotary gas separation device.    Rotary pressure swing device (100)    Rotor assembly (102)    Upper stator assembly (104)    Lower stator assembly (106)    Rotor housing (119)