GB191019249A - Improvements in the Manufacture of Ammonia. - Google Patents

Abstract

19,249. Johnson, J. Y., [Badische Anilin & Soda Fabrik]. Aug. 16. [Cognate Applications, 19,250/10 and 19,251/10.] Ammonia.-Better yields are obtained in the synthetic production of ammonia by the addition of substances termed " promoters " to the iron, nickel, or cobalt used as the catalytic agent. These substances are generally compounds of magnesium, beryllium, aluminium, or of the alkali, alkaline-earth, or rare-earth metals, or of zirconium, vanadium, tantalum, chromium, manganese, molybdenum, or tungsten. The 'addition of the oxide or other compound of magnesium or aluminium is particularly favourable. It is found, however, that certain bodies have the property of diminishing or destroying the catalytic property of the iron &c. Such bodies are, for example, arsenic, sulphur, selenium, tellurium, phosphorus, boron, antimony, bismuth, tin, lead, or zinc, or their compounds, and the presence of carbon monoxide and dioxide, and of oil in the gases should be avoided. Iron &c., which is unsuitable for use as a catalyst owing to the presence of contact poison or for other reasons, can be rendered effective by heating to a high temperature in admixture with a promoter, so that a mixture of oxides is obtained, which is reduced by means of hydrogen, preferably at as low a temperature as possible. It is preferred that the first heating should be sufficient to melt the mixture. This treatment may be repeated until the desired result is obtained. The reaction gases may be freed from contact poison by passage over a material capable of absorbing it, and this material may be a further quantity of the catalytic agent placed in advance. The mixture of iron and a promoter may be supported on a carrier, such as asbestos or chamotte, and one constituent of the carrier may constitute the promoter, but it is necessary in this case that the iron and promoter should be actually mixed together. In use, a mixture of nitrogen and hydrogen; preferably in combining proportions, is passed over the heated catalytic agent, and the reaction may be effected under great pressure as described in Specification 14,023/10.