A Comprehensive Study of Iron-Coke Briquettes’ Pyrolysis and Reduction Behaviour in an Industrial-Scale Pyrolyser

Iron-coke is a promising raw material for ironmaking blast furnaces for reducing carbon consumption and can be produced by pyrolysers, but the present pyrolysis technologies should be improved to further lower energy consumption and CO 2 emission. In this work, an integrated experimental and numerical study is conducted to investigate the pyrolysis and reduction behaviours of iron-coke briquettes in an industrial-scale gas heat carrier pyrolyser. A lab-scale two-stage tubular furnace is first employed to pyrolyze the briquette samples to obtain the recycled gas components. A DEM model is then used to simulate the packing status evolution of ellipsoidal iron-coke briquettes in the pyrolyser chamber. A CFD pyrolysis model is then used to study the pyrolysis and reduction behaviours of coke briquettes and then evaluate the impact of switching the carrier gas from traditional exhaust gas to recycled pyrolysis gas on the pyrolysis and reduction behaviours. The comprehensive in-furnace pyrolysis and reduction phenomena are illustrated. The simulation results also indicate that using the recycled gas as the gas heat carrier is beneficial to the pyrolysis efficiency and progress of ferric oxide reduction, compared to the exhaust gas. This study is useful for gas heat carrier pyrolyser design and optimisation for efficient iron-coke production.