Influence of Density on Microwave Pyrolysis of Cellulose

Herein we present the influence of sample density on the microwave induced pyrolysis of crystalline cellulose, with heating rate, biochar and bio-oil yields investigated. This Letter demonstrates that sample density is a fundamental parameter influencing microwave-assisted biomass pyrolysis, with a direct impact on heating rate, the speed of volatiles diffusion through the sample matrix and distribution of products. Of significant interest was that the maximum heating rate and bio-oil yield corresponded to an optimum sample density as a result of heat and mass transfer effects. Increase in density above this value stimulated a rise in biochar yield. The increased understanding of the mechanisms influenced by sample density in a microwave field gives increased ability for users to produce bio-oil or biochar, giving rise to improved microwave-based biorefineries for future energy and chemical needs.