Verfahren für die Herstellung von mikroporösen keramischen Membranen für die Trennung von Mischungen aus Gas und Flüssigkeit

摘要

Gas and liquid separation with membranes has either been achieved by organic polymer membranes, which are limited by low temperature stability and a separation mechanism through adsorption or solubility in the membrane matrix, or by inorganic membranes, whose gas and liquid separation efficiency is limited by Knudsen diffusion. The membranes of this invention show a temperature stability up to 500 DEG C and a gas separation with separation factors better than the Knudsen limit. Continuous microporous inorganic membranes of any desirable thickness can be prepared by e-beam evaporation of metal oxides on a support membrane, which has substantially larger pores than the metal oxide membrane. It is advantageous when the support membrane consists of the same material as the microporous membrane. The membranes are of porous structure with a narrow pore size distribution of pores, where the majority of the pores have diameters smaller than 1 nm. The membranes can be used in all areas of gas and liquid separation, where the selective separation of smaller molecules from mixtures is desired (f.e. gas concentration by removal of water from natural gas, hydrogen from synthesis gas). The membranes can also be used for the concentration of aqueous solutions (fruit juices with retention of aroma compounds, vitamines and other compounds important for the flavor and nutritional value of the juice; biological liquids like lymphe, blood, or others with retention of valuable compounds including small peptides, hormones, antibiotics and others) and for the concentration of organic solutions with retention of molecules larger than the solvent including oligomers and polymers. The membranes can also be used for the concentration of waste water with retention of organic contaminants like phenol resins and coal oil at coking plants. If the membranes have been made catalytically active, the membranes can also be used for the selective and poison resistant conduction of heterogeneously catalyzed three phase reactions by having the reaction gas diffusing through the catalytically active membrane to react at the other side of the membrane with the liquid, consisting of molecules too large to penetrate the pores.