Patent GB-1246483-A (GB)
Title: Process and device for the removal of homogeneously dissolved impurities from gases and liquids
IPC: C01B32/50
Filed: 1968-06-04
Abstract: 1,246,483. Gas separation. MESSER GRIESHEIM G.m.b.H. 4 June, 1968 [20 June, 1967], No. 26547/68. Heading C1A. [Also in Divisions B1, C5 and G1] A gas or liquid which contains homogeneously dissolved impurities is freed from such impurities by a chemisorption process which comprises bringing the gas or liquid into contact with a mass consisting of heat-stable oxide carrier material which contains, at least on its surface, at least one active component selected from the oxides of titanium, vanadium, chromium, molybdenum, manganese, rhenium, iron and nickel, the mass having been rendered active by treatment with molecular oxygen at a temperature of from 300‹ to 600‹ C. and subsequently with a reducing gas at a temperature above ambient temperature, for example of at least 200‹ C., in order to convert the active component to a lower state of oxidation. Exemplified impurities which may be removed are carbon monoxide, nitrogen oxides (for example nitrous oxide), ammonia, halogens (for example chlorine), hydrogen halides (for example hydrogen chloride), hydrogen sulphide, sulphur dioxide, sulphur trioxide, benzene (as vapour) and, especially, oxygen which may be removed from, for example, hydrogen, nitrogen, rare gases, carbon monoxide, carbon dioxide, ammonia, hydrogen halides and hydrogen sulphide. The oxide carrier material, which preferably has a surface area of from 200 to 500 m.<SP>2</SP>/g., may be silica, alumina, zirconia, thoria or a mixture thereof, for. example silica-alumina; examples of suitable commercial carrier materials are given in the Specification. The mass may contain from <SP>1</SP> to 5% by weight, calculated on an elemental metal basis, of the active component or components. The treatment of the mass with molecular oxygen may be effected with the use of pure oxygen or an oxygen-containing gas, for example air. Exemplified reducing gases are hydrogen, carbon monoxide, town gas, ethylene and saturated hydrocarbons, for example methane and propane; the reducing gas may be a gas from which impurities are to be removed. The reducing gas may be diluted with an inert gas. Preferred temperatures for the treatment of the mass with reducing gas are about 350‹ C. when such gas is hydrogen and about 250‹ C. when such gas is carbon monoxide. After treatment with molecular oxygen and with reducing gas, the mass may be purged with an inert gas, for example nitrogen, or with for example the gas from which impurities are to be removed. Impurity oxygen may be removed at a temperature of from the temperature of liquid air to the temperature at which the mass becomes thermally unstable; a mass used to remove impurity oxygen may be regenerated by following the activation procedure, i.e. by treatment with molecular oxygen and subsequently with reducing gas. When oxygen is to be removed from a reducing gas which has been used to treat the mass, the removal of oxygen preferably is effected at the temperature at which the reducing gas was used to treat the mass; removal of oxygen from such a reducing gas may be effected continuously, the mass being regenerated simultaneously by the oxygen removed and the reducing gas.