Effects of Ionic Liquid-Assisted Pretreatment of Heavy Metal-Contaminated Biomass on the Yield and Composition of Syngas Production Using Noncatalytic and Catalytic Pyrolysis and Gasification Processes

摘要

In this research, noncatalytic and catalytic pyrolysis and gasification of heavy metal-contaminated biomass (HMCB)-untreated and pretreated using a low-cost ionic liquid (IL, triethylammonium hydrogen sulfate)-are investigated. To explore the effects of the pretreatment on the yield and composition of the produced syngases, both untreated and IL-pretreated HMCB were exposed to pyrolysis and gasification processes to highest temperatures of 700 and 900 degrees C with heating rates of 30 and 5 degrees C/min without and with zeolite, tincal, and potassium carbonate catalysts, respectively. Pyrolysis results show the negative effects of IL-based pretreatment of HMCB on syngas yield and its composition. In absolute terms, tincal and zeolite play positive roles in enhancing the syngas yield and H-2 concentration obtained from catalytic pyrolysis of the IL-pretreated HMCB, but not in comparison with the pyrolysis of the raw biomass. On the contrary, the results demonstrate the synergetic effects of IL-based pretreatment of HMCB and its catalytic gasification toward higher syngas yield and H-2/CO ratio with 32 and 153% increment, respectively, compared to noncatalytic gasification of the raw HMCB. The catalytic gasification of the IL-pretreated HMCB revealed five times higher syngas yield (an H-2-enriched syngas with lower CO2 content), compared to catalytic pyrolysis using tincal.