Influence of CO2 Injection on Biomass Gasification

• Published in: Industrial & engineering chemistry research 2007-12, Vol.46 (26), p.8875-8886
• Main Authors: Butterman, Heidi C, Castaldi, Marco J
• Format: Article
• Language: English
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie071160n

The impact of CO2 cofeed (0−50% by volume) on steam gasification of biomass was investigated via thermogravimetric analysis−gas chromatography (TGA-GC). H2, CO2, CO, and CH4 gas evolution as a function of temperature were quantified for various S/C and CO2/C ratios. CO evolution enhancement became significant at temperatures above 700 °C for all woods and grasses studied. H2 evolution began at temperatures above 450 °C and began to decline above 700 °C. All samples had similar mass decay curves that were completed by 900−1000 °C and were independent of the amount of CO2 injection. Improved char conversion was observed when CO2 was present. The biomass fuels and their ash residue were analyzed using atomic absorption spectroscopy (AAS) and scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). A significant amount of highly corrosive ash residues were observed with no CO2, yet much smaller volumes were observed when CO2 was present. Finally, the experimental data was compared to ASPEN simulations to understand the influence of CO2 recycle for carbon based fuels, and they showed good agreement.