GB1286670A - Apparatus for gas separation - Google Patents

Abstract

1286670 Gas diffusion barriers ENGELHARD MINERALS & CHEMICALS CORP 8 Oct 1969 49530/69 Addition to 1125110 Heading B1L [Also in Division C1] An assembly for separating gases by diffusion, e.g. H 2 from other gases, comprises at least one centrally bored ceramic, laminated monolithic plate 15 having an inner layer (30), Fig. 2a (not shown) of coarse porosity adhered to an outer layer (31) which has at least some portions extending across the thickness thereof of fine porosity, the remainder (if any) of the outer layer (31) being of non porous material. The plates are coated with a non-porous hydrogen permeable material 20, e.g. palladium or an alloy thereof, at least on those parts which are porous to the gas being perforated. An axial bore 18 provides a hydrogen exit and has a gas impervious cap 19 at the other end. Spacing elements 17 may be as shown or in the form of integral central hubs, Fig. 2b (not shown). The fine porosity layer may also extend over the edge surface of the plates 15 as also may the palladium layer 20. Annular regions of dense non-porous ceramic may be provided at any position in the plates and may be of the same thickness, e.g. around the bore 18 or the circumference. These regions may be provided with gas holes (42), Fig. 4 (not shown), to direct the gas flow over the surfaces of the plates. The ceramic material comprises from 50-90% by weight of alkali aluminium silicates, 10-50% clay, 0-10% silica and may have 2-50% of glaze. The porosity is controlled by adding filler materials which are removed by combustion during firing, e.g. wood powder, finely divided plastics or carbon powder. In the preparation of the plates the silicate, clay, carbon and glaze are mixed and glycerin or water added with a binder, e.g. poly vinyl alcohol, methyl cellulose, acrylic resin or polyethylene glycol. An emulsion of microcrystalline wax may be used as a binder and lubricant.