SJTU Team with Collaborators Developed Double Logistic Distributed Activation Energy Model for Lignocellulosic Biomass Pyrolysis

On May 25, 2018, the scientific research team from School of Agriculture and Biology, Shanghai Jiao Tong University (China) with the collaborators from Aston University (UK) published a paper entitled Theoretical Analysis of Double Logistic Distributed Activation Energy Model for Thermal Decomposition Kinetics of Solid Fuels in Industrial & Engineering Chemistry Research.

Lignocellulosic biomass contains three major components: cellulose, hemicellulose and lignin. Through pyrolysis, lignocellulosic biomass can be converted into pyrolysis char and volatiles. The latter comprises condensable products called pyrolysis oil, which can be used both as an energy source and a feedstock for chemical production.

  

The pyrolysis kinetics is fundamental to the computational fluid dynamics simulation of biomass pyrolysis, the design and scaling-up of pyrolysis reactors, and the optimization of process operation conditions. Many models have been proposed for describing the kinetics of biomass pyrolysis, of which the distributed activation energy model (DAEM) is the most comprehensive and accurate. The experiment results showed that there were two overlapped peaks in the derivative conversion curves of biomass pyrolysis. The DAEM with a single distribution could not accurately describe this kinetic property because the thermal decomposition normally involves multiple subprocesses of various components. The Gaussian distribution is usually used to represent the activation energies. However, it is not sufficiently accurate for addressing the activation energies in the initial and final stages of the thermal decomposition reactions of solid fuels. Compared to the Gaussian distribution, the logistic distribution is slightly thicker at the curve tail and suits better to describe the activation energy distribution. The double logistic DAEM has been developed and the systematic analysis of the model has been performed including the derivation, numerical calculation, physical meaning of model parameters, analysis of typical processes of the double Logistic DAEM. The results also showed that the double Logistic DAEM was a suitable model with abundant flexibility in describing various thermochemical conversion processes of other solid fuels.

 

Junmeng Cai, Associate Professor in Agricultural Engineering from SJTU is the corresponding author, and Miss Zhujun Dong, Master Candidate from SJTU is the first author. The other co-authors include Dr. Wenfei Cai, PhD candidates Yifeng He and Meiyun Chai, and Master candidate Biaobiao Liu from School of Agriculture and Biology at SJTU, Dr. Yang Yang, Dr. Xi Yu, Dr. Scott W. Banks and Prof. Anthony V. Bridgwater from European Bioenergy Research Institute (EBRI), Aston University, UK, and  Prof. Xiangguang Zhang from Department of Chemical Engineering at Nanjing Forestry University.