Dehydration by coupling centrifuge drainage with microwave drying

• This study focuses on dehydration combining centrifuge drainage and microwave drying.
• An instrumented semi-industrial pilot has been designed.
• Experiments have been performed on mineral suspensions and textile yarn spools.
• For yarn spools the energy consumption reduction can reach 30%.
• Modeling effort has to be carried to understand physical phenomena.

In solid–liquid separation, the centrifugal drainage operation is an efficient and economic process for particulate suspensions. It is often used before a thermal drying, and its interest relies on the elimination of most of the liquid at low energetic cost. It is sometimes used to dehydrate products that are not in the form of suspensions such as textile spools. Microwave drying appears to be the most adapted technology to dry thick cakes in a centrifuge as basket rotation allows homogenizing electromagnetic fields leading to homogeneous heating.The objective of this study is the optimization of coupling processes between drainage and thermal drying. To reach this objective, the development of a model with complete description of cake desaturation during centrifuge cycles is necessary, to implement thermal energy in order to assist the mechanical operation. To demonstrate the interest of the coupling process and the validity of the model, an instrumented pilot was developed and experiments were performed with model suspensions and industrial products.