TY - JOUR
T1 - Unravelling the mechanisms of microwave pyrolysis of biomass
AU - Robinson, John
AU - Binner, Eleanor
AU - Beneroso Vallejo, Daniel
AU - Diaz Perez, Nidia
AU - Al Mughairi, Khalid
AU - Ryan, John
AU - Shepherd, Benjamin
AU - Adam, Mohamed
AU - Budarin, Vitaliy L
AU - Fan, Jiajun
AU - Gronnow, Mark J.
AU - Peneranda-Foix, Felipe
N1 - © Elsevier B.V., 2021. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy.
PY - 2022/2/15
Y1 - 2022/2/15
N2 - This study uses empirical observations and mass transfer simulations to establish a new mechanism for microwave pyrolysis of biomass. Experiments were conducted on cellulose and hemicellulose, using microwave equipment that could vary the observed heating rate. No microwave-absorbing additives were used. At high heating rates it is shown categorically that microwave pyrolysis can significantly reduce the pyrolysis temperatures for hemicellulose and cellulose, but when microwave heating is used to deliver a low heating rate the pyrolysis behaviour is identical to that obtained with conventional heating. Dielectric properties are shown to vary by over an order of magnitude depending on the heating rate. The implications of heating rate on mass transfer and phase behaviour are developed and discussed within the paper, with liquid-phase water identified as a key driver for the observed differences in the microwave pyrolysis process. This is the first study in microwave pyrolysis that is able to reconcile microwave heating phenomena against simple and well-understood mass transfer and phase equilibria effects. As a result, a number of processing strategies have emerged with the potential to use microwave heating to enable more selective pyrolysis and bio-oils with more targeted quality than has been possible with conventional approaches.
AB - This study uses empirical observations and mass transfer simulations to establish a new mechanism for microwave pyrolysis of biomass. Experiments were conducted on cellulose and hemicellulose, using microwave equipment that could vary the observed heating rate. No microwave-absorbing additives were used. At high heating rates it is shown categorically that microwave pyrolysis can significantly reduce the pyrolysis temperatures for hemicellulose and cellulose, but when microwave heating is used to deliver a low heating rate the pyrolysis behaviour is identical to that obtained with conventional heating. Dielectric properties are shown to vary by over an order of magnitude depending on the heating rate. The implications of heating rate on mass transfer and phase behaviour are developed and discussed within the paper, with liquid-phase water identified as a key driver for the observed differences in the microwave pyrolysis process. This is the first study in microwave pyrolysis that is able to reconcile microwave heating phenomena against simple and well-understood mass transfer and phase equilibria effects. As a result, a number of processing strategies have emerged with the potential to use microwave heating to enable more selective pyrolysis and bio-oils with more targeted quality than has been possible with conventional approaches.
U2 - 10.1016/j.cej.2021.132975
DO - 10.1016/j.cej.2021.132975
M3 - Article
SN - 1385-8947
VL - 430
JO - CHEMICAL ENGINEERING JOURNAL
JF - CHEMICAL ENGINEERING JOURNAL
IS - 3
M1 - 132975
ER -