Optimising food dehydration processes: energy-efficient drum-dryer operation

Current environmental policies, which promote a more sustainable food sector, have boosted efforts to reduce energy demand during processing, and particularly during drying operations. One of the routes towards more sustainable and efficient drying processes is the design and implementation of optimal operational routines for the existing drying equipment. In the food industry, drum-dryers are typically employed for the production of food powders from viscous slurries (e.g. starchy slurries). Food powders are used in a wide range of applications in the food industry, from beverage powders (milk or cocoa), instant soups, spices or flours and flavours. In this framework, we propose a model-based optimisation routine for the operation of a double drum-dryer (product under atmospheric conditions) used in the manufacture of a breakfast cereal porridge. The problem defines optimal steam temperature and optimal rotation speed that minimises the energy demand of the dryer operation for a range of operating conditions that considered different: product formulation, final moisture contents, thickness and initial temperature of the wet slurry. Overall, this work demonstrates the potential of model-based approaches to the design and optimisation of more sustainable and efficient industrial drying technologies in the food sector, which can help in the achievement of short/medium-term energy reduction goals.