Agglomeration of nickel oxide particle during hydrogen reduction at high temperature in a fluidized bed reactor

• Published in: Chemical engineering research & design Vol. 168; pp. 193 - 201
• Main Authors: Lee, Jae-Rang, Kim, Yong-Ha
• Format: Journal Article
• Language: English
• Published: Rugby Elsevier Ltd 01.04.2021; Elsevier Science Ltd
• Subjects: Agglomeration; Chemical reactions; Chemical reduction; Fluidization; Fluidized bed reactor; Fluidized bed reactors; Fluidized beds; Gas-solid reactions; Heterogeneous; High temperature; Homogeneous; Hydrogen reduction; Nickel; Nickel oxides; Reaction time; Temperature effects; Fluidized bed reactor; Heterogeneous; Agglomeration; Fluidization; Homogeneous
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2021.02.005

•Agglomeration of NiO have occurred under high temperatures.•Heterogeneous fluidization has caused the cohesion of particles to grow up to 20 times.•At high temperatures, channeling was caused by agglomeration.•The reduction reaction of NiO in agglomeration was low. This study examined the effect of temperature and time on the reduction reaction, agglomeration, and fluidization of NiO particles in a fluidized bed reactor. NiO particles, which are classified as Geldart group B, showed homogeneous fluidization at 600°C. Above 700°C, heterogeneous fluidization and a low reduction reaction were observed, and the agglomeration rate of the particles increased. From 600 to 900°C, the reduction rate increased up to 40min of reaction time and decreased with increasing agglomeration rate at a reaction time over 40min. Above 700°C and over 40min resulted in a low extent of gas-solid reaction owing to agglomeration of the particles. The structure and distribution of nickel and oxygen in the product were verified at various reaction temperatures, based on SEM, TEM, and EDS analyses.