| 摘要 |
<PICT:0974439/C1/1> <PICT:0974439/C1/2> In producing ammonia by reacting nitrogen and hydrogen at elevated temperature and pressure over an iron catalyst which is replaced at intervals in its entirety, additional interim replacements are effected with fresh pre-reduced catalyst of that part of the catalyst charge with which the reactant gases first come into contact. In Fig. 1, the reactant gases enter at 1, and are pre-heated in 2, 3, before passing up space 4 and across electric heater 5. The pre-heated gas passes through catalyst beds 6-10, each separated by cooling coils 13-16, and reaction products are withdrawn through heat-exchanger 11, and line 12. At least one of the catalyst beds, e.g. 6, or 6 and 7, is subjected to interim replacement as shown in Fig. 2. Inert gas, e.g. N2, is introduced at the base of the reactor, while catalyst is aspirated through pipe 18 by means of a pump, 19, operating in association with water-tank, 20. Coarse and fine catalyst is separated in cyclones 22, 23, and the gas, freed from catalyst, is driven back through line 26 to pipe 25 by pump 19, to prevent air entering the reactor and causing an outbreak of fire. |
