GB191227955A - Improvements in, or connected with, the Manufacture of Hydrogen. - Google Patents

Abstract

27,955. Johnson, J. Y., [Badische Anilin & Soda Fabrik]. Dec. 4. Catalytic materials. - Catalytic masses, containing finely-divided iron oxide, for use in producing hydrogen from mixtures of carbon monoxide and steam are prepared (1) by starting with finely-divided iron which becomes more or less oxidized, giving rise, for example, to a mixture of oxides. Or a compound of iron which gives rise to iron oxide may be used. The substance used can be supported on carriers or used as a fine powder, or in a fine porous condition, but preferably is used in the form of porous lumps, briquettes, &c. An oxide, hydroxide, or a salt difficult of solution, e.g. iron carbonate, may be precipitated from a solution of an iron salt, or produced by heating, a suitable salt, such as iron oxalate or nitrate. The product is, if desired, after moistening and adding a suitable organic or inorganic diluent or binding-agent, formed into lumps, which are then heated, before or after introduction into the contact furnace. The porosity of the lumps may be increased by the addition, before heating, of substances which evolve gases on heating, and the decomposition of such substances can often be accelerated by passing gases such as air, carbon dioxide, furnace gas, or water-gas over the compounds during heating. The following examples of the production of the catalytic masses are given: (1) Solutions of sodium carbonate and ferrous sulphate are mixed, the precipitate is filtered off and mixed wet with slaked lime, or with an agent decomposable upon heating, such as calcium nitrate, or a mixture of that salt and ammonium nitrate; the mass is dried to a paste, kneaded, rolled out, and cut into cubes, which are dried and heated. (2) Finely-divided iron oxide, such as crocus martis, and a solution of aluminium or magnesium nitrate are somewhat similarly treated, the heating being effected in a current of air. (3) A mixture of caustic lime, water, and caustic potash is stirred into a melted ferric-nitrate crystals, and the product is mixed with the precipitate of the first example; the mixture is dried, kneaded, rolled, cut, dried again, and heated with or without passage of a current of air or carbon dioxide. (4) Ferric nitrate is heated and stirred until the nitric acid is almost completely driven off ; the residue is sieved and mixed with calcined magnesia and moistened with potassium carbonate solution. The mass is briquetted, dried, and heated. (5) Potassium carbonate and iron oxide, obtained by carefully heating the oxalate, are stirred into a stiff wheat-starch paste, and the mass is kneaded, briquetted, dried, and heated. Gum tragacanth, gum arabic, or dextrin, may be used instead of starch. (6) A paste of ferric-oxide hydrate, ferric oxalate, and calcium nitrate solution is pressed into suitable shapes and dried slowly at 500‹ C. in a current of air. The oxalate may be omitted. (7) Ferric oxide, obtained as in the fourth example, is mixed into a paste with aluminium nitrate solution. The paste is then suitably moulded and heated until the nitrous gases are driven off.