Patent ID: 7896949

Claim:
A method for separating carbon dioxide from a fluid stream comprising carbon dioxide and hydrogen with selectivity higher than Knudsen diffusion selectivity, said method comprising contacting a porous membrane with the fluid stream at a temperature greater than about 200° C., the porous membrane comprising a porous support and a continuous porous separation layer disposed on a surface of the porous support and extending between the fluid stream and the porous support layer; wherein the porous support comprises alumina, silica, zirconia, stabilized zirconia, stainless steel, titanium, nickel-based alloys, aluminum-based alloys, zirconium-based alloys or a combination thereof; the porous separation layer comprises titania, MgO, CaO, SrO, BaO, La 2 O 3 , CeO 2 , HfO 2 , Y 2 O 3 , VO z , NbO z , TaO z , ATiO 3 , AZrO 3 , AAl 2 O 4 , A 1 FeO 3 , A 1 MnO 3 , A 1 CoO 3 , A 1 NiO 3 , A 2 HfO 3 , A 3 CeO 3 , Li 2 ZrO 3 , Li 2 SiO 3 , Li 2 TiO 3 , Li 2 HfO 3 , A 4 N 1 y O z , Y x N 1 y O z , La x N 1 y O z , HfN 2 y O z , or a combination thereof; median pore size of the porous separation layer is less than about 10 nm; and A is La, Mg, Ca, Sr or Ba; A 1 is La, Ca, Sr or Ba; A 2 is Ca, Sr or Ba; A 3 is Sr or Ba; A 4 is Mg, Ca, Sr, Ba, Ti or Zr; N 1 is V, Nb, Ta, Cr, Mo, W, Mn, Si or Ge; N 2 is V, Mo, W or Si; x is 1 or 2; y ranges from 1 to 3; and z ranges from 2 to 7.