| 摘要 |
The activity of conventional iron-based ammonia synthesis catalysts is enhanced by supplying alkali to the finished catalyst by vapor transpiration, either during preparation of the catalyst or during its use in a synthesis operation, or during both. The catalyst used may contain one or more conventional promoters, including alkali embodied in the catalyst during its manufacture. The vapor transpiration provides increased effective alkali at the catalyst surfaces in the form of an inorganic compound, such as the hydroxide, carbonate or hydride. It avoids the problem of loss of surface area which would result from adding more alkali during manufacture of the catalyst. Vapor transpiration conditions, especially the relative temperatures of the vaporization chamber and hence the alkali vapor partial pressure in the catalyst chamber, are controlled to achieve an effective deposition while avoiding pore blockage or reduction of surface area. |
