Numerical Simulation of Thermal and Mass Behaviors During Pyrolysis Homogeneous Reaction Within a Screw Reactor

In this study, a three-dimensional numerical analysis has been presented to simulate pyrolysis process involving transfer phenomena within a tubular reactor equipped with a rotating screw. A specific computational fluid dynamics code based on the finite volume method is developed in order to solve the general governing equations of momentum, energy and species concentration coupled with the thermochemical reaction of pyrolysis. The developed model aims to simulate the interaction between the kinetics of pyrolysis and transfer phenomena. Besides, the influence of various dimensionless numbers which are axial Reynolds number (Rea), mass Damkohler number (Dam), thermal Damkohler number (Dath), dimensionless activation energy (E*) and preheat parameter (τ) on the temperature and species concentration fields has been studied. It was found that the decrease in the axial Reynolds number, the thermal Damkohler number and the activation energy enhances the rate of conversion of the cellulose. However, the results of the numerical simulation have shown that the increase in the mass Damkohler number and the inlet temperature improves the cellulose conversion rate.