Modelling, simulation and optimization of a continuous multistage torrefaction reactor with a separator for the torrefaction process using mustard husk
摘要
Renewable biomass energy represents a diversity of energy sources that maintain the equilibrium of different ecosystems. However, one of the biggest obstacles to using agricultural waste biomass like mustered husk as a cellulosic feedstock is the low bulk density, high moisture content, storage degradation, and poor energy density of raw lignocellulose biomass. Biomass torrefaction has been recognised as a technically feasible method for converting raw biomass into green torrefied charcoal, with a high-energy density and lower oxygen-to-carbon ratio. The developed technology continuous multistage torrefaction reactor enhances the torrefaction method, which has a rotary drum with modified blades (RDMB) and a solid gas cyclone separator (SGCS) to separate the torrefaction gas from the torrefied charcoal. ANSYS Fluent was used to simulate and optimise the continuous multistage torrefaction reactor. The optimised parameters of the torrefaction process, such as velocity, blade angle, temperature and residence time, were 0.8 RPM, 20°, 543 K and 20 min, respectively. The separation efficiency of SGCS was 100% for particle sizes from 0.5 mm and above. It was also observed that green charcoal powder is 0.5 to 2 mm, indicating that SGCS could be an alternative to conventional separation processes. This research shows overall significant effect on torrefaction process in terms of mass and energy yield and torrefied charcoal properties, such as calorific value, moisture, volatile content, and ash content are 61%, 92%, 4896 Kcal kg−1, 2%, 20% and 16%, respectively. Thus, the present work significantly improves the continuous torrefaction process with the continuous separation of torrefied charcoal and torrefaction gas.
Graphical abstract