Modeling, simulation and estimation of optimum parameters in pyrolysis of biomass

Pyrolysis is a process by which a biomass feedstock is thermally degraded in the absence of air/oxygen. It is used for the production of solid (charcoal), liquid (tar and other organics) and gaseous products. The present work involves the estimation of optimum parameters in the, pyrolysis of biomass for both non-isothermal and isothermal conditions. The modeling equations are solved numerically using the fourth order Runge-Kutta method over a wide range of heating rates (25-360 K/s) and temperatures (773-1773 K). The simulated results are compared with those reported in the literature and found to be in good agreement qualitatively in the range of operating conditions covered, but some very interesting trends are found, especially with respect to the effect of net heating rate and temperature on final pyrolysis time. The final pyrolysis time first decreases at lower values of net heating rate or temperature and then increases as net heating rate or temperature is further increased, providing an optimum value of net heating rate or temperature at which final pyrolysis time is minimum. This interesting phenomenon, which was not reported by investigators earlier, is well explained by means of the pyrolysis kinetics. (C) 2002 Elsevier Science Ltd. All rights reserved.