Spray drying is used for the manufacture of many consumer and industrial products such as instant dairy and food products, laundry detergents, pharmaceuticals, ceramics, and agrochemicals. During spray drying, agglomerates of powder particles are formed which determine the instant properties of the powder. Agglomeration during spray drying is considered to be a difficult process to control. The main cause of this is the complex interaction of the process variables: the atomization process, the mixing of spray and hot air, the drying of suspension droplets and the collision of particles which might lead to coalescence or agglomeration. As a consequence, agglomeration during spray drying is operated by trial-anderror. In an EC-sponsored project, named the EDECAD projects, an industrially validated computer model, using CFD technology, to predict agglomeration processes in spray drying machines is developed. An Euler-Lagrange approach with appropriate elementary models for drying, collision, coalescence and agglomeration of the dispersed phase is used. The main result of the EDECAD project is a so-called ''Design Tool,'' which establishes relations between the configuration of the drying installation (geometry, nozzle selection), process conditions, product composition and final powder properties. The Design Tool is being validated on pilot-plant scale and industrial scale. It will provide an advanced tool for improved design and optimization of spray drying and agglomeration equipment, to improve the quality of products and to increase the productivity of such equipment. This article introduces the background and approach of the project and some preliminary results.

-Spray drying is used for the manufacture of many consumer and industrial products such as instant dairy and food products, laundry detergents, pharmaceuticals, ceramics and agrochemicals. During spray drying, agglomerates of powder particles are formed, which determine the instant properties of the powder. Agglomeration during spray drying is considered to be a difficult process to control. The main cause of this is the complex interaction of the process variables: the atomization process, the mixing of spray and hot air, the drying of suspension droplets and the collision of particles which might lead to coalescence or agglomeration. As a consequence, agglomeration during spray drying is operated by trial-and-error. In an EC-sponsored project, named the EDECAD project and co-ordinated by NIZO food research, an industrially validated computer model, using Computational Fluid Dynamics (CFD) technology, to predict agglomeration processes in spray drying machines is developed. An Euler-Lagrange approach with appropriate elementary models for drying, collision, coalescence and agglomeration of the dispersed phase is used. The main result of the EDECAD project is a so-called "Design Tool", which establishes relations between the configuration of the drying installation (geometry, nozzle selection), process conditions, product composition and final powder properties. The Design Tool is being validated on pilot-plant scale and industrial scale. It will provide a tool for improved design and optimisation of spray drying and agglomeration equipment, to improve the quality of products and to increase the productivity of such equipment. This paper introduces the approach of the project and some preliminary results. spray drying / agglomeration / computational fluid dynamics / modeling Résumé -Simulation de l'agglomération dans les équipements de séchage par atomisation : le projet EDECAD. Le séchage par atomisation est utilisé dans la fabrication de nombreux produits de consommation et de produits industriels, tels que les aliments en préparation instantanée et les poudres laitières, les détergents pour lessive, les produits pharmaceutiques, céramiques ou agrochimiques. Au cours du séchage, des agglomérats de particules de poudre sont formés, qui déterminent les propriétés d'instantanéisation de la poudre. L'agglomération pendant le séchage par atomisation est un processus difficile à maîtriser, principalement en raison de l'interaction complexe des variables opératoires comme le mode d'atomisation, le mélange du spray avec l'air chaud, le séchage des gouttelettes en suspension et la collision des particules pouvant conduire à la fusion ou à l'agglomé-ration. En conséquence, l'agglomération au cours du séchage est opérée par approximations successives. Dans un projet appelé EDECAD, soutenu par l'union européenne et coordonné par le NIZO, un modèle informatique validé industriellement, utilisant la technologie CFD, a été développé pour prédire l'agglomération dans les équipements de séchage par atomisation. Une ap...

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