Biomass temperature profile development and its implications under the microwave-assisted pyrolysis condition

Microwave-Assisted Pyrolysis (MAP) is a highly scalable process that has the potential to realize the Distributed Biomass Energy Production System (DBEPS) concept. This study was to illustrate the heating properties of MAP when applied to biomass, and to demonstrate the feasibility of manipulating the heating operation to fully utilize exothermic reactions as a means to save energy. Alternate microwave heating of corn stover revealed exothermic reactions occurring in temperature ranges of 188.4–224.0 °C and 367.0–387.0 °C. These exothermic reactions can potentially sustain the pyrolysis reactions in the absence of external heat sources, indicating that alternative dielectric heating is a practical energy-saving operation mode for MAP. Analysis of the liquid products obtained from different heating intervals suggests that it is possible to selectively extract the primary pyrolysis products by collecting the condensables at specific heating times. The solid chars produced during MAP have desirable microwave absorbent properties and could be recycled in the MAP process.