Torrefaction is considered as a kind of mild pyrolysis that is carried out in inert atmosphere (usually nitrogen). During this process, the moisture of the initial fuel and part of volatiles are removed from the biomass particles into the inert atmosphere resulting in advanced biomass properties as high energy density, hydrophobicity and durability. The most beneficial result of torrefaction process is that biomass feedstock logistics cost can be reduced, as less tones of biomass are required for a given amount of energy input. The development of a process model examining basic parameters as reaction temperature and residence time can provide useful information, which can be used for the more efficient design of a torrefaction reactor. This study presents such a process model for a straw torrefaction pilot plant. This model is based on the thermodynamic calculation of a single and/or a two batch reactor, built in the commercial software ASPEN Plus. The calculation of required flow rates of inert gas, cooling medium for a specific biomass feedstock value, is based on relevant results found in the literature.
Nikolopoulos, N., Isemin, R., Atsonios, K., Kourkoumpas, D., Kuzmin, S., Mikhalev, A., Nikolopoulos, A., Agraniotis, M., Grammelis, P., Kakaras, E. Modeling of wheat straw torrefaction as a preliminary tool for process design, Waste and Biomass Valor