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Relationship between reaction and diffusion during ultrafine NiO reduction toward agglomeration fluidization
Author(s) -
Li Jun,
Zhu Qingshan,
Li Hongzhong
Publication year - 2021
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.17081
Subject(s) - non blocking i/o , economies of agglomeration , fluidization , nucleation , diffusion , materials science , reduction (mathematics) , grain boundary diffusion coefficient , grain boundary , grain growth , chemical engineering , fluidized bed , particle (ecology) , grain size , thermodynamics , metallurgy , mechanics , chemistry , catalysis , microstructure , engineering , physics , mathematics , geology , geometry , biochemistry , oceanography
The relationship between reaction and diffusion during ultrafine NiO reduction by H 2 in a fluidized bed reactor were investigated. The result illuminates that the reduction reaction proceeding in the unreduced NiO powders is according to the nucleation model. A modified force balance model between cohesive and collision forces incorporating grain‐boundary diffusion and reaction is proposed to predict the agglomeration behavior of ultrafine Ni during the reduction of NiO in a fluidized bed. The modified force balance model shows more precise predictions than the model without consideration of grain‐boundary diffusion. Based on the model, it is found that the core of the two‐step reduction is to decouple grain growth from reduction for achieving full conversion while retaining nanosized grain sizes.