The biomass pyrolysis process usually could be expressed by a threepseudocomponent modelThe value of reaction order in the traditional threepseudocomponent model is set as 1 or 3In this study

the kinetic parameters of three pseudocomponents (activation energy

prefactor and reaction order) were calculated from the threepseudocomponent model with undefined reaction order by the nonlinear least square fitting methodThe analysis result showed that the reaction order of cellulose decomposition was close to one

which agreed with the conclusions of other researchersThe reaction order of lignin decomposition was related to the type of biomass sample

and was close to one or threeThe most complex process was hemicellulose decompositionThe reaction order of hemicellulose decomposition changed in the range of 1.5 to 4Several threepeseudocomponent models based on the weight average activation energy calculated by the Ozawa method were comparedThe threepseudocomponent model with undefined reaction order was more accurate than the other two models to describe the biomass pyrolysis process.