Effect and functioning mechanism of spheronization and calcination on oxygen carrier performance in mid-temperature CH4 chemical looping reforming

Bimetallic oxygen carriers hold great promise for CH 4 chemical looping reforming at 500–700 °C. Current research focuses on material optimization of lab-scale powders. However, industrial use requires mass production, shaping, and calcination—causing performance shifts from lab samples. Therefore, this study explored how beads-shaping and calcination affect a 10-kg-scale Fe–Ni oxygen carrier. Compared to powder, spheronized beads increased H 2 generation in reduction stage. Calcination at 1300 °C produced 2.5-time stronger beads than 1200 °C. Both calcined beads had 10-15 percentage points lower CH 4 conversion at 550–600 °C, recovering to >92 % at 650 °C. The calcined beads produced 0.4–0.6 more H 2 from per CH 4 , though requiring more oxygen carrier input. Microscopical reasons to performance change were the shifts in reaction pathway and the forming of Fe–Ni–Al spinel. Macroscopical reasons were the oxygen release influenced by topology change. This work identifies key shaping and calcination parameters critical for oxygen carrier commercialization.