Background

Once chemicals are commercially synthesised on a large scale, industrial driers apply thermal and mechanical action to dry the product into powder. Under certain problematic operating conditions, these products end up stuck to the sides of the drier (see picture above), leading to wastage and the need for expensive manual removal and cleaning of the equipment. The drying process is complex, involving both phase change, particle collision and mechanical action.

From a fundamental scientific standpoint, there is still a great deal to understand about this process, despite its common use in industrial settings. From a practical standpoint, new predictive modelling approaches are needed to inform and accelerate industrial process design, as this is an area where much process development occurs through trial and error.

We will work with industry partner Syngenta to develop a new multiphysics model to characterise the material properties of drying powders, enabling the identification of key causes and trends in wall adhesion. Through Syngenta’s involvement, we will have access to experimental to guide the project inform modelling decisions.

Project Objectives for the PhD project

The aim of the project is to understand the drying process in commercial driers from a continuum perspective. Starting from established models of granular flows and complex fluid flows that incorporate plasticity, the project will explore the impact of drying and the stress applied by the mixing action in the drier on the nucleation of stuck layers of material.

Outcomes

• Motivated by experimental data, build a theoretical model to understand the dominant physics in the drying process.
• Develop a well-documented open-source code to simulate a suitable reduced problem of the drying process.
• Generate a database quantifying expected performance under different operating conditions from the resulting model for Syngenta’s future reference.