Comparative study of the pyrolysis of almond shells and their fractions, holocellulose and lignin. Product yields and kinetics

A comparison between the thermal decomposition of almond shells and their components (holocellulose and lignin) was carried out, considering the yields of the most important products, under flash conditions, and the decomposition kinetics. The yields of the main gaseous products obtained in the fast pyrolysis of almond shells can be reproduced from the yields obtained with holocellulose and lignin. The best results were obtained with CO, water and CO2. The differences were greater with the minor hydrocarbons, CH4, C2H6, C2H4, etc. The kinetics of the slow thermal decomposition (TG-DTG) of almond shells cannot be reproduced by the sum of lignin and holocellulose. The cellulose from almond shells decomposes at lower temperatures than almond shells, and the behavior of isolated lignin is very different from that found when it forms part of the raw material, proving the importance of the interactions between its components.