Study of the reaction mechanism for preparing powdered activated coke with SO2 adsorption capability via one-step rapid activation method under flue gas atmosphere

• The one-step rapid activation method under flue gas atmosphere for powdered activated coke preparation is divided into three distinct reaction stages based on reaction time. • Stage I (0–0.5 s) involves rapid volatile release and O2 consumption; Stage II (0.5–2.0/3.0 s) couples carbonization and activation; Stage III (2.0/3.0–4.0 s) focuses on CO2 and H2O(g) activation. • The first two stages create diffusion channels and activation sites essential for the final activation stage, enhancing SO2 adsorption capability. • Understanding the reaction mechanism provides critical guidance for reactor design, sizing, and optimal activator nozzle placement in industrial PAC production.