Biomass pyrolysis devolatilization kinetics of herbaceous and woody feedstocks

Devolatilization kinetics were determined using a modified micropyrolyzer reactor for several biomass feedstocks: switchgrass, corn stover, red oak, and pine. The micropyrolyzer was directly coupled to a flame ionization detector (FID) to track the release of volatiles from the biomass. Time series data from these experiments was analyzed to determine apparent devolatilization rates. Care was taken to assure the experiments were isothermal and kinetically limited calculating a Biot number less than 0.1 and pyrolysis numbers greater than 10, which simplifies the derivation of devolatilization rates. A single, first order reaction was able to model devolatilization rates at temperatures up to 500 degrees C. No correlation was found between the inorganic content of the biomass and its rate of devolatilization. Apparent activation energies were in the range of 54.9-88.4 kJ mol(-1). The rate coefficient at 500 degrees C was calculated as 1.90-5.14 s(-1) for the four feedstocks.

Automated summary

The study used a modified micropyrolyzer reactor to determine devolatilization kinetics of switchgrass, corn stover, red oak, and pine, showing that a first order reaction could model devolatilization rates at temperatures up to 500 degrees C. No correlation was found between inorganic content and devolatilization rate.