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Kinetics of reduction of nickel oxide with CO
Author(s) -
Krasuk J. H.,
Smith J. M.
Publication year - 1972
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690180308
Subject(s) - carbon monoxide , nickel , chemistry , activation energy , nickel oxide , oxide , inorganic chemistry , pellets , reaction rate constant , adsorption , carbon fibers , materials science , catalysis , kinetics , composite material , organic chemistry , physics , quantum mechanics , composite number
Initial rates were measured for the reduction of single pellets of nickel oxide with carbon monoxide at atmospheric pressure and temperatures from 566 to 796°C. The nickel oxide pellets were porous ( ϵ 0 = 0.032 − 0.35) and intrapellet diffusion retarded the rate so that the shrinking core model was not applicable. Effective diffusivities for the lower porosity pellets were very small, corresponding to tortuosity factors of about 180 for ϵ 0 = 0.032 and 92 for ϵ 0 = 0.062. The reaction appeared to be first order in carbon monoxide. Rate constants, based upon the intraparticle area, indicated an activation energy of 47 kcal/g.‐mole over the temperature range 566 to 682°C. At higher temperatures the rate was constant. These results, while not conclusive, are in agreement with a reaction sequence consisting of formation of nuclei of nickel atoms in the nickel oxide surface, rapid adsorption of carbon monoxide at the nickel‐nickel oxide interface, migration of the adsorbed carbon monoxide to the adjacent lattice, and a slow reaction to extract oxygen from the lattice.