Scale-up How do we get it right first time?
Scale-up in the context of fast moving process developmentcan be problematic. Getting scale-up right requires anunderstanding of the way in which physical and chemicalprocess parameters interact to determine overallperformance. Multiphase systems are particularly difficult.The most common types of scale-up problem at thereaction stage will be shown, and the root causes will bediscussed and exemplified. Common root causes are:increases in overall processing time on scale-up, withpossible adverse effects on yield and quality; differences inheat transfer capability, which can feed back to increasesin cycle time; changes in mass transfer rates, which canimpact on reaction time and selectivity; poor dispersionof solids (mass transport), leading to low reaction ratesand stalled reactions; and changes in mixing efficiencyin homogeneous reactions, with implications for reactionselectivity. A procedure for identification of potentialscale-up problems will be described.