Modeling of industrial biomass fluidized bed gasification system and optimization of operating conditions

Abstract

Carbon emissions from fossil fuel combustion have emerged as a critical constraint on sustainable industrial development. Biomass gasification gas (BGG) represents a promising decarbonization pathway; however, the reliance on single-source biomass cannot ensure the operational reliability of industrial fluidized bed gasifiers. A key challenge to large-scale BGG adoption lies in the limited adaptability of fluidized bed reactors to different biomass, which exhibit heterogeneous physicochemical properties. Moreover, industrial research on the impact of structural parameters on gasification efficiency remains scarce. To investigate the impact of different biomass on gasification performance in fluidized-bed reactors, this study developed an industrial-scale fluidized-bed gasifier model using the Aspen Plus fluidized-bed module, based on an 8 t/h biomass gasifier operating in a regional facility. Key parameters, including equivalence ratio (ER), gasification pressure, and gasification temperature, were systematically evaluated to assess their effects on BGG composition and gasification efficiency. Furthermore, model validity was rigorously validated through computational and experimental data comparisons of critical design parameters. The results demonstrated that gasification temperature and ER are critical factors influencing biomass gasification efficiency. When the gasification temperature increased from 650 to 900 °C, the gas yield variation of corn stover and wooden blocks reached a maximum of 0.17 m³/kg. For corn stover gasification, the volumetric fractions of H₂, CO, CO₂, and CH₄ exhibited an increasing trend, rising by 11.43 %, 8.41 %, 7.73 %, and 2.24 %, respectively. Notably, biomass briquette gasification showed the most significant increase in H₂ fraction (11.4 %). Balancing operational safety and efficiency, the optimal gasification temperature was identified as 850 °C, with an ER range of 0.15–0.2. Increased biomass moisture content (2 %–25 %) reduced CH₄ concentration from 4.08 % to 2.95 %, lowering the overall BGG calorific value. Air temperature exhibited negligible impacts on gasification performance. Implementation of these findings in industrial biomass gasifiers validated the optimized parameters of the model can accurately predict and guide actual experiments, with <20 % deviation in BGG composition under optimized conditions.