摘要:
An SCR catalyst containing titanium, molybdenum and vanadium has the particular characteristic that its catalytic activity is significantly less than that of a tungsten-containing catalyst. That disadvantage has been compensated for in the past by using a comparatively large volume of catalyst. In contrast to the conventional practice of using a molybdenum oxide proportion of about 10 to 12% by weight, the invention proposes that the molybdenum proportion of the catalyst, in the form of molybdenum trioxide MoO.sub.3, is about 0.01 to 5% by weight, preferably 1.5 to 4% by weight, relative to the weight of the catalyst mass. A catalyst containing this amount of molybdenum thus has an activity comparable to that of a tungsten-containing catalyst. The invention is applicable to all deNO.sub.x catalytic converters which call for the simultaneous presence of a reducing agent, in particular plate-type and honeycomb-type catalytic converters.
摘要:
In an arsenic resistant mixed oxide catalyst and a process for producing the same, oxides of at least the metals vanadium and molybdenum are provided, especially for reducing nitrogen oxides in flue gases in the presence of a reducing agent such as ammonia and carbon monoxide. A MoO.sub.3 phase and at least one oxygen-rich mixed oxide phase such as V.sub.9 Mo.sub.6 O.sub.40 is at least partly converted into a mixed oxide phase being poorer in oxygen such as a V.sub.9 Mo.sub.4 O.sub.25 phase, for increasing arsenic resistance.