Scale-up – How do we get it right first time?

Scale-up in the context of fast moving process development can be problematic. Getting scale up right requires an understanding of the way in which physical and chemical process parameters interact to determine overall performance. Multiphase systems are particularly difficult. The most common types of scale up problem at the reaction stage will be shown, and the root causes will be discussed and exemplified. Common root causes are: increases in overall processing time on scale-up, with possible adverse effects on yield and quality; differences in heat transfer capability, which can feed back to increases in cycle time; changes in mass transfer rates, which can impact on reaction time and selectivity; poor dispersion of solids (mass transport), leading low reaction rates and stalled reactions; and changes in mixing efficiency in homogeneous reactions, with implications for reaction selectivity. A procedure for identification of potential scale-up problems will be described.