Author: Ram Chandra PaulPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The kinetics of the steam reforming of methane over perovskite catalysts with the formula LaCr1-xNixO3 (x = 0.25 & 0.40) have been examined over a wide range of temperatures (500°C to 1000°C) and atmospheric pressure. These catalysts work well from 700 to 900°C for methane conversion (space velocity = 13,500 hr-1 , and gas composition is CH4 : H2 : H2 O : Ar = 2 : 3 : 6 : 30), the higher nickel content (Ni = 0.40) catalyst is more active than the lower nickel content (Ni = 0.25) catalyst. The water-gas shift reaction is close to equilibrium, while the steam reforming reaction is not at equilibrium for the conditions studied. Activity behaviour is in agreement with 'Marko's' methane oxidation result (1 ). However, these catalysts are unstable in the reforming environment, as they partially reduce to elemental nickel at high temperatures (worked up to 1000°C. Structural changes (from orthorhombic to rhombohedral) occur at lower temperatures (investigated up to 750°C). The higher nickel content catalysts are less stable than the lower nickel content catalysts.