Gas Separation Process for CO2 Removal from Natural Gas with DDR-type Zeolite Membrane

The DDR-type zeolite membrane (DDR Membrane) with an aperture of 0.36 × 0.44 nm was formed on a porous alumina substrate by hydrothermal process. We have succeeded in scaling up the DDR Membrane element into a large monolithic structure with a diameter and length of 180 mm and 1,000 mm, respectively. The CO2/CH4 selectivity exceeded 100 for mixed gas of 70 mol% CO2 at 8.0 MPag, 45 degC. This high selectivity improves hydrocarbon recovery compared to the conventional polymeric membrane. The DDR Membrane is suitable for CO2 separation for high CO2 natural gas fields.