Insights into exergy analysis of air-steam biomass gasification for H₂ production via kinetic modeling

The aim of the research article is to investigate the extraction of maximum usable energy in terms of exergy utilizing gasification of eucalyptus wood sawdust. The physical and chemical exergy and the exergy efficiency of H₂ gas are critically analyzed using surface kinetic modeling which is based on Langmuir-Hinshelwood mechanism. Four important gasification parameters, namely gasification temperature (T = 900–1200 K), equivalence ratio (ER = 0–0.4), steam-to-biomass ratio (SBR = 0–2), and char particle size (Dp = 100–2000 μm), are varied to study their effect on H₂ exergy. The exergy trend for different parameters induced by the chemical reactions involved in the gasification progression is elaborately discussed. The results reveal that exergy is highly influenced by T followed by SBR and ER. In absence of air at T = 1150 K, the highest H₂ yield and the exergy values are obtained by fixing SBR as 0.75 and Dp as 1000 μm.