What are the reasons for the deterioration of distributed quality during scale-up? An explanation of the essence of how results change between the lab and mass production, along with design points to ensure reproducibility.
澁谷工業 メカトロ統轄本部
While dispersion was successful in the lab, transitioning to mass production leads to sedimentation and aggregation, resulting in unstable quality. Such challenges occur in many settings. One cause is that simple scale-up does not reproduce the flow conditions and shear conditions. Merely increasing the size of the stirrer significantly changes the forces acting on the particles and the dispersion state, making it impossible to achieve the same results as in the lab. This is particularly true for high-viscosity systems and nanoparticle dispersions, where even slight differences in conditions can greatly affect dispersion quality. Additionally, batch processing is susceptible to the effects of residence time and mixing uniformity, making it difficult to ensure reproducibility. To address these challenges, it is crucial to review the entire process, including shear history and flow design, rather than just scaling up the equipment. Approaches that maintain consistent conditions, such as inline continuous processing, are needed to reduce variability in dispersion state and replicate lab results in mass production. Furthermore, during scale-up, indicators such as energy density and circulation frequency become important, necessitating designs that maintain the amount of shear applied per unit volume. From this perspective, ensuring reproducibility throughout the entire process is key to stable production.
