| 摘要 |
This invention is a catalytic element for use in the catalytic oxidation of ammonia. The element comprises a foraminous structure fabricated from a material consisting essentially of a metal selected from the group consisting of platinum, rhodium, palladium and alloys of mixtures thereof characterized by (a) a novel configuration whereby the initial product of the formula: curve the flat ratio (C/F) multiplied by mesh count in inches (N) and wire diameter (dw), for said element is greater than at least about 0.08 and (b) where, for a given hydrogen throughput, the conversion efficiency is a function of the curve to flat ratio (C/F), wire diameter (dw) and mesh count (N) combination and conversion efficiency is improved by increasing the mesh count (N) for a given wire diameter, increasing the wire diameter (dw) for a given mesh count, and increasing the curve to flat ratio (C/F) to a ratio of above 1.0. Preferably the initial product of the formula is greater than 0.2, more preferably 0.9 and the curve to flat ratio (C/F) is above about pi /2. The preferred initial product of the formula is in the range of from 0.08 to about 10 and more preferred from about 0.9 to about 10. The preferred element is woven gauze, knitted fabric, fibers and combinations thereof. The element can be in a series of said elements as a plurality of screens.
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