Towards a multiscale model-based design of spray drying processes

Buchholz, Moritz

• Publisher: Cuvillier Verlag
• Year: 2023
• Print ISBN: 9783736977747
• eBook ISBN: 9783736967748
• Edition: 1

This work focuses on the experimental and numerical investigation of different aspects of the spray drying process on multiple scales with the aim to develop a model-based workflow to support the design of spray dryers. On the droplet scale, acoustic levitation is used for single droplet drying experiments with the aim of gaining insights into the drying kinetics and the particle formation processes. The findings are compared to spray drying experiments on pilot scale. A novel approach of a coupled CFD-DEM simulation for single suspension droplets allows for a detailed description of the solidification mechanisms. The boundary conditions of the droplet simulation are extracted from CFD simulations of the spray dryer. Finally, a reduced order model for the spray drying process based on a multi-compartment approach is presented which uses the information from the detailed CFD simulations to accurately describe the drying processes. This model is applicable in the context of flowsheet simulations to simulate complete process chains involving spray dryers.

Table of contents

• Symbols
• 1 Introduction
• 1.1 Motivation
• 1.2 Outline
• 2 Fundamentals of the spray drying process
• 2.1 Atomization
• 2.2 Droplet drying and particle formation
• 2.3 Single droplet drying experiments
• 3 Experimental investigations of the spraydrying process
• 3.1 Material characterization
• 3.2 Pilot scale spray dryer experiments
• 3.3 Single droplet drying experiments using acoustic levitation
• 4 Numerical flow simulation of spray dryers
• 4.1 Theoretical background
• 4.2 Data extraction and processing
• 4.3 Validation
• 4.4 Summary
• 5 Detailed simulation of a single suspension droplet
• 5.1 Model overview
• 5.2 Numerical analysis
• 5.3 Particle formation
• 5.4 Summary
• 6 Development of a reduced order spray dryer model
• 6.1 Model structure
• 6.2 Governing equations
• 6.3 Numerical Analysis
• 6.4 Validation
• 6.5 Production scale plant
• 6.6 Summary
• 7 Conclusions
• Bibliography
• A Experimental investigation
• B CFD simulation
• C Coupled CFD-DEM simulation
• D Reduced order model