Patent GB-163047-A (GB)
Title: Improvements in and relating to the process of preparing mixtures of nitrogen and hydrogen such as are suitable for the production of ammonia
IPC: C01B21/04
Filed: 1921-05-09
Abstract: Mixtures of nitrogen and hydrogen suitable for the synthesis of ammonia are prepared by cracking hydrocarbon in the presence of air and steam, then catalytically oxidizing the contaminating carbon monoxide, and finally removing the carbon dioxide produced with ammonia.  The high-temperature treatment in tubes of iron-chromium alloy or other refractory material of a gas oil, air and steam, yields a mixture of nitrogen, hydrogen, carbon dioxide, carbon monoxide, and water vapour.  This mixture is passed over ferric oxide or other catalyst maintained at a high temperature, whereby the bulk of the carbon monoxide is oxidized to carbon dioxide at the expense of the steam; any residual carbon monoxide is eliminated by preferential combustion in the presence of such a catalyst as that described in Specification 163,046.  The carbon dioxide content of the gas mixture is now removed by treatment with ammonia, prepared as below and preferably in aqueous solution, leaving a mixture of nitrogen and hydrogen which is in the proportions requisite for ammonia synthesis provided the starting materials for the cracking operation were suitably proportioned.  The hydrogen and nitrogen of the mixture are then caused to combine in the known manner under pressure and at high temperature in presence of a catalyst preferably comprising a metallic cyanamide or cyanide; the resulting ammonia is absorbed in water and a desired proportion-in practice, the whole-of the solution is used for the afore-mentioned elimination of carbon dioxide.ALSO:Ammonium carbonate is prepared by first producing the mixture of nitrogen and hydrogen by cracking a hydrocarbon in the presence of air and steam, then catalytically oxidizing the contaminating carbon monoxide, and finally removing the carbon dioxide produced with ammonia.  The high-temperature treatment in tubes of iron-chromium alloy or other refractory material of a gas oil, air and steam yields a mixture of nitrogen, hydrogen, carbon dioxide, carbon monoxide and water vapour.  This mixture is passed over ferric oxide or other catalyst maintained at a high temperature, whereby the bulk of the carbon monoxide is oxidized to carbon dioxide at the expense of the steam; any residual carbon monoxide is eliminated by preferential combustion in the presence of a catalyst. The carbon dioxide content of the gas mixture is now removed by treatment with ammonia, preferably in aqueous solution, leaving a mixture of nitrogen and hydrogen.  This mixture is then caused to combine in the known manner under pressure and at high temperature in presence of a catalyst; the resulting ammonia is absorbed in water and a desired proportion-in practice, the whole-of the solution is used for the aforementioned elimination of carbon dioxide.  The ammonium carbonate obtained may be transformed into ammonium sulphate.  The Specification as open to inspection under Sect. 91 (3) (a) states that the ammonium carbonate may be converted into ammonium sulphite by treatment with sulphur dioxide, the sulphite being then oxidized to sulphate in any way, say by passing air through its aqueous solution in the presence of a catalyst such as vanadium pentoxide.  This subject-matter does not appear in the Specification as accepted.