Optimization studies for hydrothermal gasification of partially burnt wood from forest fires for hydrogen-rich syngas production using Taguchi experimental design

Highlights: • Hydrothermal gasification of partially burnt wood was studied using Taguchi design. • Statistical studies on temperature, time, particle size and feed concentration. • Contribution of factors: temperature > feed concentration > time > particle size. • H₂ yield (5.3 mmol/g) maximum at 500 °C, 45 min, 10 wt% feed concentration. • Liquid effluents contained aromatics, phenols, aldehydes, ketones and hydrocarbons. Forest fires significantly affect the wildlife, vegetation, composition and structure of the forests. This study explores the potential of partially burnt wood recovered in the aftermath of a recent Canadian forest fire incident as a feedstock for generating hydrogen-rich syngas through hydrothermal gasification. Partially burnt wood was gasified in hydrothermal conditions to study the influence of process temperature (300–500 °C), residence time (15–45 min), feed concentration (10–20 wt%) and biomass particle size (0.13 mm and 0.8 mm) using the statistical Taguchi method. Maximum hydrogen yield and total gas yield of 5.26 mmol/g and 11.88 mmol/g, respectively were obtained under optimized process conditions at 500 °C in 45 min with 10 wt% feed concentration using biomass particle size of 0.13 mm. The results from the mean of hydrogen yield show that the contribution of each experimental factors was in the order of temperature > feed concentration > residence time > biomass particle size. Other gaseous products obtained at optimum conditions include CO₂ (3.43 mmol/g), CH₄ (3.13 mmol/g) and C₂–C₄ hydrocarbons (0.06 mmol/g).