Influence of temperature and heating rate on the fixed bed pyrolysis of meat and bone meal

This work is focused on the study of meat and bone meal pyrolysis in a fixed bed reactor, analysing the influence of the final pyrolysis temperature and heating rate on the product (char, tar and gas) distribution and composition and the char characterization. Two sets of experiments have been performed at different final pyrolysis temperatures between 300 and 900 °C and heating rates from 2 to 14 °C/min. From the results obtained it is observed that the effect of the final pyrolysis temperature is more important than the effect of the heating rate, except on the temperature profiles. The analysis of pyrolysis product distribution shows that the major products obtained were tar and char at any temperature or heating rate. Most of the decomposition takes place at temperatures lower than 500 °C, and no more significant decomposition is produced above 750 °C. The chars obtained present a low specific surface area, less than 45 m2/g. The tar obtained is mainly composed of more than 60% nitrogenated aliphatic compounds (such as nitriles, amides and cyclic compounds), 15% aliphatic hydrocarbons (such as alkanes and alkenes), 10% oxygenated aliphatic compounds (mostly carboxylic acids) and about 8% oxygenated aromatic compounds (mainly phenolics).