Pseudo-components of hemicellulose and lignin for the kinetic modelling of biomass pyrolysis

Sustainable feedstocks such as lignocellulosic biomass and agricultural wastes can be integrated as feedstocks in pyrolysis and gasification within platform chemical production systems. The low quality of biomass as a fuel and the limited knowledge on the chemical mechanisms of volatilisation are still challenges in the implementation of such technologies. Hemicellulose and lignin have important chemical variations within plant species and after biomass treatment, which are outside of the capability of current pyrolysis kinetic models. This study creates a chemical kinetic model that can (i) be readily adapted to different types of lignocellulosic biomass relying in their chemical composition, and (ii) offer detailed information of pyrolysis product composition within a satisfactory level of accuracy. A detailed lumped-mechanistic model (Ranzi's model) is used as benchmark to adapt the use of new pseudo-components of hemicellulose that include new chemical fragments, such as acetyl side-chains, uronic acids, and hexose carbohydrates. Reaction stoichiometry and kinetics of the new pseudo-components were defined to more accurately reflect the identified chemical, as determined using different characterisation techniques. Through this approach, the applicability and accuracy of semi-empirical kinetic models can be extended to new biorefining feedstocks.