Airflow Optimization in a Double Gasification Furnace to Produce Syngas and White Charcoal

The co-production of white charcoal and synthesis gas from rice husk was investigated in a dual-system furnace, which decouples pyrolysis and gasification processes. This study evaluated the relationship of air feed rate 0.08–0.16 kg/s on process efficiency and product quality. Increasing the air feed rate reduced production time from 141 to 69 minutes. An optimal air feed rate of 0.12 kg/s was identified for producing high-quality white charcoal, characterized by a maximum calorific value of 18.5 MJ/kg and an electrical resistance of 22.0 Ω. The charcoal yield ranged from 37-47%. A critical trade-off was observed in energy recovery, higher air feed rates favored syngas recovery and enhanced gasification efficiency at the expense of white charcoal energy recovery. This paper shows that the dual-system furnace, by separating the reaction zones, effectively optimizes the simultaneous production of both value-added products through precise control of the air feed rate.