Fast microwave assisted pyrolysis of biomass using microwave absorbent

A novel concept of fast microwave assisted pyrolysis (fMAP) in the presence of microwave absorbents was presented and examined. Wood sawdust and corn stover were pyrolyzed by means of microwave heating and silicon carbide (SiC) as microwave absorbent. The bio-oil was characterized, and the effects of temperature, feedstock loading, particle sizes, and vacuum degree were analyzed. For wood sawdust, a temperature of 480 °C, 50 grit SiC, with 2 g/min of biomass feeding, were the optimal conditions, with a maximum bio-oil yield of 65 wt.%. For corn stover, temperatures ranging from 490 °C to 560 °C, biomass particle sizes from 0.9 mm to 1.9 mm, and vacuum degree lower than 100 mmHg obtained a maximum bio-oil yield of 64 wt.%. This study shows that the use of microwave absorbents for fMAP is feasible and a promising technology to improve the practical values and commercial application outlook of microwave based pyrolysis.