Numerical simulation and performance evaluation of throat sizing in an updraft fixed bed reactor for biomass gasification

This study presents a comprehensive numerical modeling approach to analyze and evaluate the performance of a throat biomass updraft fixed bed gasification reactor through computational fluid dynamic simulations. The numerical model uses detailed kinetics to capture the complex thermochemical processes within the gasifier. The influence of key parameters such as reactor design on the gasification efficiency and producer gas composition are systematically investigated. Also, performance metrics, including cold gas efficiency, hydrogen-carbon monoxide ratio, and producer gas heating value, are employed to quantitatively quantify the effectiveness of the throat updraft fixed bed gasification reactor to assess the reactors performance under varying configurations. The hydrogen and carbon monoxide concentrations increased by 6.5 % and 5.2 % by changing the throat diameter ratio from 0.14 to 0.33, respectively. Increased gasification efficiency is also observed, from 65.5 % to 77.84 %, within the same ratio range increase. Similarly, a 2.6 % increase is observed in the lower heating valve between the models with throat-to-diameter ratio of 0.14 and 0.33. The findings contribute to a deeper understanding of the gasification process in throat reactors, offering insights into optimization opportunities for enhanced producer gas quality and overall efficiency.