Aspen Plus Simulation of Biomass Gasification: a Comprehensive Model Incorporating Reaction Kinetics, Hydrodynamics and Tar Production

Energy generation from biomass through gasification has been a keen area of research for a long time. However, gasification still needs to overcome a significant number of challenges for its wider acceptability. Even though experimental works on lab-scale biomass gasifiers are available, computational modelling and simulations are crucial in predicting the system performance. Process simulation and analysis of fluidized bed gasification using Aspen Plus software are considered in this study. Among the three Aspen Plus models developed in the present study, model 1 and model 2 are developed based on equilibrium and kinetic approach, respectively. In addition to this, reaction kinetics, gasifier geometry and bed hydrodynamics are considered in model 3. The model-predicted values are then validated against experimental data. Minimum values of mean error, root mean square error, mean absolute error and mean absolute percentage error, are observed for model 3. As model 3 realistically represents the gasification process, the impact of gasification temperature and equivalence ratio on the product gas composition, lower heating value, cold gas efficiency and carbon conversion efficiency are systematically studied using this model. The model is simulated at temperatures ranging from 680 to 800 degrees C and equivalence ratio of 0.24-0.32. The simulation results indicated that higher operating temperature and lower equivalence ratio enhanced the gasification process. Benzene is identified as the primary component of tar with a composition of 9.79 g/kg(biom).