Design optimization and scale-up characteristics of a double-helical ribbon reactor for biomass catalytic pyrolysis

Abstract

Pyrolysis characteristics are closely related with the inner mixing performance of biomass and biochar particles in agitated biomass catalytic pyrolysis reactors. In this study, a novel double-helical ribbon reactor was designed for biomass catalytic pyrolysis. DEM (Discrete Element Model) simulations were performed to optimize the structure and operating conditions. Model calibration and validation experiments were firstly conducted. The effects of structural parameters and rotation speed on mixing performance were further explored. The results showed that the mixture homogeneity was closely related to the impeller outer diameter and rotation speed, while the mixing rate could be optimized by adjusting the inner diameter and pitch. The optimal operation condition showed adequate mixing in the axial and radial directions. Besides, the scale-up analysis demonstrated that similar mixing performance was presented at the same Froude number. Finally, the correlations of mixing characteristics provided a theoretical reference for industrial reactors design.