Simulation of Corn Stover and Distillers Grains Gasification with Aspen Plus

A model was developed to simulate the performance of a lab-scale gasifier and predict the flowrate and composition of product from given biomass composition and gasifier operating conditions using Aspen Plus software. Mass balance, energy balance, and minimization of Gibbs free energy during the gasification were applied to determine the product gas composition. Carbon conversion efficiency and tar content were provided to the model as inputs as these could not be predicted by the model based on minimization of Gibbs free energy. Experiments for validation of the model were performed on a lab-scale fluidized bed gasifier using corn stover and distillers grains as the feed materials. Steam to biomass ratio, equivalence ratio, and furnace temperature were varied during the gasification. The results show that temperature of the gasifier bed was most influential on the product gas composition. However, higher freeboard temperature may have increased formation of CO and decreased CO2 in the final gas composition.