Influence of Density on Microwave Pyrolysis of Cellulose

Abstract

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.