A study of particle flow in a ribbon reactor: Effect of ribbon configuration on mixing and heat transfer performance

Abstract

The mixing and heat transfer of particles are two important operating units in the lithium-ion battery industry due to the cycling performance of the cathode is mainly dependent on the mixing and heat transfer performance of granular matter, such as needle coke and asphalt particles. In this work, simulations of the particle mixing and heat transfer process in a ribbon reactor were conducted based on the three-dimensional discrete element method (DEM). The stacking angle test, rotary drum, and thermal conductivity test were designed to obtain the DEM parameters. The trajectory of tracer particles, total velocity fluctuation, coordinate number, and relative standard deviation (RSD) were used to analyze the mixing and heat transfer process. It was found that particles in the ribbon reactor experience two types of movement. The first one is high-speed tangential movement, and the second one is low-speed recirculation movement in the vertical plane. Particles near the vessel wall and impeller shaft are first heated and a cold core is generated in the initial stage of heat transfer. Results obtained indicate that the mixing performance increases slightly with the increase of ribbon number. The mixing performance increases with the increase of velocity fluctuation and the decrease of coordination number, and the heat transfer can be improved by enhancing the mixing performance of granular matter. Increasing the ribbon width and ribbon pitch can improve the heat transfer performance, while the ribbon pitch has little influence on the mixing performance.