GB163026A - A new or improved process and apparatus for the production of concentrated nitrous gases - Google Patents

Abstract

163,026. Norsk Hydro - Elektrisk kvaelstofaktieselskab. May 5, 1920, [Convention date]. Void [Published under Sect. 91 of the Act]. Nitrogen oxides; nitric acid.-In the absorption of dilute nitrous gases by means of solid absorption agents, and the decomposition of the resulting product to produce concentrated nitrous oxides and nitric acid, the combined process is conducted in retort-like, acid- and fire-proof vessels surrounded by gas-tight jackets capable of resisting comparatively high pressures. The hot gases before actually entering the retorts pass into the space between the jacket and the retort in order to heat the latter and thus enable either absorption or decomposition to take place. The absorbent may be such as is described in Specification 137,071 consisting of a mixture of a dry base with one or more metallic oxides, and the absorption is advantageously effected at 300-600‹ C. In one form of the apparatus shown in the Figure, the furnace gases first pass to the vessel C containing material fully saturated with nitrous gases through the valve B, but before entering the inner retort, traverse the interstices between the jacket and the retort. To facilitate the decomposition which is preferably effected at a pressure below that of the absorption, a small portion of the furnace gases is led through the valve D actually into the retort and carries with it the concentrated nitrous gases and nitric acid to the exit F. The greater portion of the furnace gases leave the vessel C by the valve G and enters the second vessel H containing fresh or de-nitrated material, after passing through the space between the retort and the jacket. The residual gases freed from nitrous gases escape through the valve I and pipe L. When the material in the vessel H becomes saturated, the circulation of gases is reversed, i.e. the furnace gases enter the vessel H and then pass on to C. The valve D may be shut off entirely, the necessary gases then entering the retort through holes in the retort walls. Alternatively the retort walls may be made porous. Instead of two vessels, a battery connected on the counter-current principle or in any suitable manner may be employed.