CFD-based scale-up and environmental assessment of a rotating drum leaching reactor for WEEE recycling

One of the most challenging engineering tasks is the scale-up of a device. The information transfer between the different scales is crucial because similar yields and conversions should be achieved in a pilot and an industrial-scale device, which were obtained in a laboratory-scale unit. To maintain the same performance, the construction and operating parameters are often changed during the scale-up procedures. Traditionally, dimensionless numbers can be used to calculate the proper operating parameters and sizes for the scale unit. However, a validated computational fluid dynamics (CFD) simulator can be an excellent tool to perform scale-up studies with less time and energy consumption. This work reports a scale-up procedure aimed at supporting the building of a pilot plant-scale leaching reactor, used for the dissolution of metals form waste electric and electronic equipment. Particularly, the process deals with the dissolution of copper which has the second highest economic potential after precious metals. The scale-up studies are based on the validated model of the laboratory-scale reactor. Different construction and operating parameters were tested using CFD simulations. The different cases were evaluated based on conversion (leads to economic potential) and environmental assessment. COMSOL multiphysics will be used as CFD software and MATLAB for conversion and utility calculations and also for environmental assessment.