Study on the pyrolysis kinetics of Pinus sylvestris pine cones by model-free fitting method and model-fitting method
Using the TA Q600 synchronous thermal analyzer,the 2～3 mg pinecone particles with a particle size of 250～420 μm were linearly heated to about 1 073 K at the heating rate of 10 K/min,15 K/min,20 K/min and 25 K/min in an air atmosphere.Model fitting method(Coats-Redfern method,Zsako method,Satava-Sestak method)and no model fitting method(KAS method,Doyle method,FWO method)were used to solve and compare the kinetic parameters of pine pyrolysis,and the value of activation energy E and pre-index factor A were calculated.The results show that the pyrolysis of Pinus sylvestris pine cones in-cludes four stages,and the mass loss ratio of the main mass loss stage is more than 85%.The average activation energies obtained by the modelless fitting method were 74.3 kJ/mol(Doyle method),71.8 kJ/mol(FWO method)and 68.3 kJ/mol(KAS method),respectively,and the fitting curves of the activation en-ergies of KAS method and the predigital factor were>0.95.The average activation energies obtained by model fitting were 65.4 kJ/mol(Zsako method),62.4 kJ/mol(Satava-Sestak method),56.4 kJ/mol(Coats-Redfern).The average activation energy of Zsako method,and Satava-Sestak method is closer to the activa-tion energy without model,and the pre-exponential factor of Satava-Sestak method can reflect the complexity of the pyrolysis reaction mechanism.This paper suggests that KAS method and Satava-Sestak method should be combined to better evaluate the burning property of Pinus sylvestris pine cones.
Pinus sylvestris pine conesthermogravimetric analy-sismodel-free fitting methodmodel-fitting methoddynamics
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