Catalyst contg. platinum and palladium based layers - used in oxidn. of ammonia to form nitric oxide

摘要

Layered catalyst material, based on precious metals, is used in the oxidn. of ammonia to form nitric oxide, partic. during the prodn. of nitric acid. In the first part of the catalyst material to be in contact with the flow of reaction gases, the principal component is Pt. In the second part the principal component is Pd. The amt. of Pd-based catalyst is determined so that the unit charge, calculated for the Pt-based catalyst, omitting the Pd-based catalyst, and expressed in tonnes of ammonia per 24hr. per m2 of active geometric surface, is >0.25 (1+p) where p is the pressure in the oxidn. reactor expressed in atmos absolute. Compared with previous Pt-based catalyst giving the same yield for the oxidn. reaction, the material contains a reduced amt. of Pt-based catalyst, and the irrecoverable loss of Pt is also reduced.