Deoxygenated pyrolysis-gasification of biomass for intensified bio-oil and syngas co-production with tar abatement

Deoxygenation-based biomass gasification provides a feasible solution for the effective utilization of biomass and value-added syngas production. However, the behavior of bio-oil formation during the pyrolysis stage and the characteristics of tar abatement at the gasification stage with applied deoxidizer still require exploration. Thus, this study investigates the effects of different deoxidizer/biomass (D/B) mass ratios, pyrolysis -gasification temperatures, and water -injection velocities on the composition and yield of bio-oil and tar -elimination law. The techniques of 2D HSQC nuclear magnetic resonance, attenuated total reflectance, gel permeation chromatography, and gas chromatography -mass spectrometer are used to investigate the formation behavior and evolution law of the bio-oil produced. The results indicate that the addition of the deoxidizer not only improves the quality and yield of syngas but promotes the deoxygenation of oxygen -containing bio-oil by donating electrons. Specifically, the phenolic compounds decreased by 12.4% under D/B = 0.3 as compared with D/B = 0. The results also confirm the promoting effect of tar elimination via reforming and cracking by Fe and CaO, respectively: Tar production during the gasification stage decreased by 54% under D/B = 0.3, as compared with nondeoxygenation. This study demonstrates the superiority of iron -calcium -based deoxidizer in bio-oil deoxygenation and tar elimination, which will promote the development of deoxygenation-based bio-oil and syngas polygeneration.