Effect of operating conditions on emission concentration of PAHs during fluidized bed air gasification of biomass

Abstract

With the concern of future energy use, hydrogen is taken as an important role in energy alternatives. In addition, biomass air gasification by using fluidized bed is an efficient and advanced method for hydrogen production. Despite of energy product generation, some pollutants such as PAHs easily formed in gasification process because of tar decomposition. Accordingly, this study provides a fundamental work of emission behavior of PAHs generated under different operating conditions such as temperature, air factor, and addition of catalysts. The experimental result shows the emission concentration of PAHs decreases with the operating temperature increases, but PAHs increases with increasing of air factor. Besides, addition of CaO resulting a reduce influence on PAHs emission, but Al 2 O 3 added in fluidized bed cause bimodal particle size segregate and reduce fluidized bed quality that leads PAHs formation during biomass air gasification.

Tars from Fluidized Bed Gasification of Raw and Torrefied Miscanthus x giganteus

“…The peak production of total GC-detectable tar is observed for both feedstocks between 750 and 800 °C, which is in line with the trends observed for other feedstocks. 8,9 For torrefied M×G, the total GC-detectable tar did not decrease significantly after its peak production at 750 °C, which can be attributed to (1) decomposition of some heavy GC undetectable tar into the GCdetectable tar fraction due to thermal tar cracking, 9,35 (2) higher thermal stability of light PAHs due to the higher content of aromatic lignin in torrefied M×G 7 resulting in higher total GCdetectable tar yield, and (3) limited steam reforming of tars due to lower water content in the product gas derived from torrefied M×G.…”