GB158593A - Improvements in or relating to the protection of the walls of enclosures in which reactions take place under high temperatures and pressures - Google Patents

Abstract

158,593. Claude, G. Aug. 29, 1919. Ammonia, catalytic production from nitrogen and hydrogen; catalytic apparatics; high pressure apparatus. - Relates to the protecting of the walls of the enclosure in which an exothermic reaction is carried out under high pressure and at a high temperature, for instance the synthesis of ammonia using " hyperpressures " according to Specification 130,086. The layer of molten material G interposed between the chamber C in which the reaction takes place and the pressure - sustaining wall A, is, by selection, of bad thermic conductivity, neutral with respect to the bodies present, and of low vapour tension; suitable materials are a metallic chloride, caustic soda or potash, a eutectic mixture of the latter, and borax dissolved in boric acid. To prevent transmission of heat by convection, the molten material may be held stationary by the addition of solid material of bad thermic conductivity such as sand, coke, powdered magnesia, or magnetic oxide of iron, employed in a granular or pulverulent state in such a manrner as to form a paste or pulp. Substances such as litharge may be added to the molten material to absorb hydrogen &c. that may become dissolved therein and which might attack the wall of the enclosure. In the apparatus shown, the catalyst E is contained in an inner tube B, surrounded at the lower part by an electrical heating-device D and the reaction gases enter at the connection H, pass through the annular or helical space between the tubes B, C, then traverse the catalyst E where they are brought to reaction, and finally escape through the connection I. At the point where the gases enter, the temperature is insufficient to lead to deterioration of the wall A, and it is adequate to continue the molten material G to a height X at which the temperature ceases to become injurious to the wall. Several layers of liquids may be employed, the more fusible at the top and extending down to a level L and the less fusible from the level L to the level O; such viscous liquid may consist of boric acid containing an increasing proportion of borax.