Polymer separation membrane for purifying methane
AssigneeAxiom Angewandte Prozesstechnik Ges.M.B.H.
InventorAleksander MAKARUK
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Abstract
The use of polymer separation membranes to selectively separate CO2 and H2 from CH4 in a membrane separation step for purifying methane contained in an optionally pre-dried product gas mixture of a methanation method which contains CH4, H2 and CO2 is described. a) The separation is carried out at an operation temperature TB between −20° C. and 100° C.; and b) the polymer membranes b1) are able to simultaneously separate CO2 and H2 from CH4, b2) have a higher selectivity for the separation of CO2 than of H2 from CH4, i.e., a ratio α1/α2<1, and b3) have a glass transition temperature Tg that is lower than the operation temperature TB.
Claims16
A polymer separation membrane for selectively separating CO2 and H2 from CH4 in a membrane separation step for purifying methane contained in an optionally pre-dried product gas mixture of a methanation method which comprises CH4, H2 and CO2,
- wherein
- a) the separation is carried out at an operation temperature TB between −20° C. and 100° C.;
- and
- b) the polymer membrane
- b1) is able to simultaneously separate CO2 and H2 from CH4,
- b2) has a higher selectivity for the separation of CO2 than of H2 from CH4, i.e., a ratio α1/α2<1, and
- b3) has a glass transition temperature Tg that is lower than the operation temperature TB.
A method for producing methane, comprising the following steps:
- a methanation step in which, by reducing CO2 with H2, a product gas is formed that comprises H2O, H2 and CO2 in addition to CH4;
- optionally a drying step in which H2O is removed from the product gas;
- and
- a membrane separation step for purifying the methane, wherein the gas mixture obtained by drying and containing CH4, H2 and CO2 is subjected to separation using separation membranes being able to selectively separate CO2 and H2 from CH4;
- wherein
- a) the separation in the membrane separation step is conducted at an operation temperature TB between −20° C. and 100° C.;
- and
- b) polymer membranes are used that
- b1) are able to simultaneously separate CO2 and H2 from CH4,
- b2) have a higher selectivity for the separation of CO2 than of H2 from CH4, i.e., a ratio α1/α2<1, and
- b3) have a glass transition temperature Tg that is lower than the operation temperature TB.
Dependencies are inferred from the claim text.