Institute of Solids Process Engineering and Particle Technology

In this project, the continuous spray granulation of sodium benzoate solution will be investigated. This material acts as model system for any acid-base formulation frequently applied in industry e.g. for catalyst manufacturing. The usual production process of the salt of interest involves a tank reactor, in which the acid-base reaction takes place in liquid state, followed by a fluidized bed for drying and granulation as formulation step. In order to make the spray granulation step autonomously adaptable for a SMART reactor and to produce particles with e.g. tailor-made morphology, flowability or crystalline fraction, both the process parameters and the residence time distribution need to be adjustable in-line, which is the main goal within this project. Adjustment of these parameters is required when for example the nozzle gets blocked, lumps are formed or slight fluctuations in gas supply occur. The residence time distribution will be adjusted by the installation of vertical weirs in the process chamber that influence the particle movement, the relation of convection and diffusion and thus the final product quality and homogeneity. The optimal configuration and design of the weirs need to be identified with the aim of a narrow residence time distribution and a low degree of back-mixing. For achieving a high flexibility and level of detail at the same time, the transfer geometries will be produced by additive manufacturing. The experimental part of the project with the Lagrangian sensors for in-line detection of granulation state will be complemented by simulations using the novel rCFD (recurrence Computational Fluid Dynamics) method that performs on time scales close to real-time or faster.

More infos:

SMART continuously operated fluidized bed for spray granulation with self-regulating residence time distribution