Kinetic study of meat and bone meal pyrolysis: an evaluation and comparison of different possible kinetic models

Alternative treatments such as gasification or pyrolysis need to be developed for the disposal of meat and bone meal (MBM). The present work is focussed on a study of the pyrolysis of MBM in a thermobalance in order to compare different possible kinetic methods of obtaining information about the MBM decomposition process. Previous experiments were performed to establish the optimum operating conditions. Several dynamic experiments were then carried out at low heating rates (5, 10, 15 and 20 °C/min) up to 900 °C under the optimum operating conditions obtained, 250-350 μm, 15 mg and 100 cm3/min NTP of nitrogen. Different kinetic models were tested and compared, considering one fraction or two, three or four fractions decomposing simultaneously. The basis of comparison was the goodness of the fit with regard to the linear correlation coefficients of the lines αexperimental = αcalculated and dα/dTexperimental = dα/dTcalculated. The most valuable kinetic expressions and the kinetic parameters obtained are shown. The kinetic model which best describes the decomposition of MBM considers four fractions decomposing simultaneously following a second order equation (F2). However, other models tested with lower fitting parameters values can also be considered satisfactory depending on the degree of accuracy required in the kinetics. The results obtained with the different models were compared with those found in the literature.