Simulation of air-steam gasification of pine sawdust in an updraft gasification system for production of hydrogen-rich producer gas

Abstract

In this paper, a kinetic model of biomass gasification for H2-rich syngas production is proposed using Aspen Plus process simulator. Having obtained the syngas composition, various parameters and characteristics of the biomass gasification can be determined; they include the gas yield, H2/CO, gas higher heating value (HHV), Carbon conversion efficiency (CCE) and cold gas efficiency (CGE). The gas yield and H2/CO increase as temperature increases from 750 °C to 900 °C. CCE and CGE were also found to increase with increasing temperature. Increasing equivalence ratio (ER) increases the gas yield and CCE due to the decreased concentration of chars in the products. Air induction also decreases the concentrations of combustible gases in the syngas, thereby decreases the HHV of the product gas. H2/CO shows a slight change with ER increasing from 0.1 to 0.4. The detailed analyses performed in the course of the present article reveals that the steam is a feasible gasification agent that can be utilized to generate a syngas with high H2 content. H2 increases from 16.75 vol% to 18.46 vol% with increasing S/B from 0.25 to 1.0. The gas HHV decreases with increasing S/B due to a slight decrease in CH4 content.