Enhancing thermal decomposition in cylindrical reactors: A finite element analysis of thermal aspects and fluid dynamics for thermosensitive, exothermic compounds

_This work numerically investigates the thermal decomposition of compound A in a thermosensitive exothermic cylindrical reactor. The study primarily focuses on the influence of the reactor's configuration and heating temperature on its total performance. Simulations of reactors with 2, 4, 6, and 8 hot cylinders are performed using COMSOL Multiphysics 5.0 and finite element analysis, taking the heating temperatures as 30 °C, 40 °C, and 50 °C using an activation energy of 70 kJ/mol with an initial fluid velocity of 0.001 m/s. The results depicted that at 50 °C, the performance of the 4-cylinder reactor was the best; indeed, the exit concentration of reactant 'A' compared to that in the 2-cylinder reactor was decreased by 20.42 %, and the reaction rate of 25.5 mol/m 3 .s proved high conversion efficiency along with favorable thermal conditions. The 4-cylinder reactor showed better performance against all other reactors, namely the 6-cylinder and 8-cylinder reactors, through both reaction rate and conversion efficiency. Also, the cylinder size variation analysis for the 4-cylinder reactor shows that increasing the radius (R cyl ) of the cylinder from 2 mm to 4 mm gave a higher exit temperature of 56.332 °C, a 74.63 % reduction in the exit concentration of 'A' compared to a cylinder size of 2 mm, while the competitive reaction rate becomes 26.1 mol/m 3 .s. Although the reaction rate for the 4 mm radius cylinder was somewhat lower than that for the 2 mm radius, the larger size managed heat much more effectively, and the 4-cylinder reactor with a 4 mm radius at 50 °C was the most optimal configuration. This setup provides the best balance of high reaction rates, efficient conversion, and effective thermal conditions for thermal decomposition, offering significant insights into reactor design optimization.