Parametric studies of heat and mass transfer process for two-stage biochar production from poultry litter pellet biomass.

The study presents a parametric study of pyrolysis of poultry litters under isothermal heating conditions using a two-stage pyrolysis scheme and a downer separation technique. The study aims to increase the yield of biochar through pyrolysis using a two-stage kinetic process. The thermo-physical properties of mild steel and poultry litter were used to develop a simulation with a finite element method and COMSOL multiphysics to predict biochar yield at different temperatures and residence time. The numerical model was validated by comparing the predicted and the experimental results from the literature with a percentage difference of 1.3 to 11% and an R² value of 0.9124. Further parametric studies showed that for the pyrolysis of 0.5 kg of poultry litters, a maximum yield of biochar of 42.9% was obtained at a lower temperature of 573.15^oK with a residence time of 9000 s. Higher temperature favoured gas yield while biochar yield declined. [ABSTRACT FROM AUTHOR]