Pyrolysis Mechanism of Victorian Brown Coal Under Microwave and Conventional Conditions for Hydrogen-Rich Gas Production

Fast microwave pyrolysis technology can effectively convert brown coal into hydrogen-rich syngas. However, the unique pyrolysis behaviour of brown coal under microwave conditions is not fully understood in comparison with conventional pyrolysis. This study used Victorian brown coal as a raw material to conduct pyrolysis experiments under conventional and microwave heating methods. The results demonstrate that the microwave-assisted pyrolysis of Victorian brown coal can selectively crack polar functional groups, enhancing H2 and CO production via radical-driven secondary reactions and gasification, while conventional heating favours the formation of tar containing phenols and fewer aromatic compounds. The result is a high-quality syngas (75.03 vol.%) with a hydrogen yield of 10.28 (mmol Gas/g Coal (daf)) at 700 °C under microwave heating, offering a scalable route for valorising low-rank coals.