Pyrolysis of Shrinking Cylindrical Biomass Pellet

In the present study, impact of shrinkage on pyrolysis of biomass particles is studied employing a kinetic model coupled with heat transfer model using a practically significant kinetic scheme consisting of physically measurable parameters. The numerical model is used to examine the impact of shrinkage on temperature profile and pyrolysis conversion time considering cylindrical geometry. Finite difference pure implicit scheme utilizing TDMA is employed for solving heat transfer model equation. Runge-Kutta 4 order method is used for chemical kinetics model equations. Simulations are carried out for radius ranging from 0.0000125 m to 0.025 m, temperature ranging from 303 K to 1100 K and shrinkage factors ranging from 0.0 to 1.0. The results obtained in the present study are in excellent agreement with many experimental studies, much better than the agreement with the earlier models reported in the literature. The impact of shrinkage reflects on pyrolysis in several ways. The temperature profile of the particle changes due to increased density and decreased distance across the pyrolysis region. The magnitude of the temperature gradient is more for shrinking particle as compared to non-shrinking particle. Shrinkage affects the pyrolysis time in thermally thick regime. Pyrolysis conversion process is fast for shrinking particle as compared to nonshrinking particle.