A transient unimodel for reacting pellets is considered with various modes
of heat and mass transfer and structural changes for wood pyrolysis. Pellet
breakup was found to be possible from strength calculations. This leads to
an increase in the number of pellets and a decrease in the resistance to h
eat and mass transfer. The pressure and temperature buildup within 2.7 mm t
hick pellets was measured for wood pyrolysis/combustion experimentally. The
bimodal wood pyrolysis was analyzed, and the rate constant and activation
energy were found. Pellet breakup may also be used as a transient catalytic
process where the catalysts become smaller as they break up in time.