Seth Huggins and Ken McRae. Process Engineering and Development, Amgen, Inc., 1 Amgen Center Drive, MS 99-1-A, Thousand Oaks, CA 91320
During process development, variability in processing times were observed for a multi-step, heterogeneous reaction to produce an API intermediate. It was determined that at the reaction temperature of interest the reaction was mass transfer limited. The studies to be discussed will be on the techniques used to determine the mass transfer coefficient and how the surfaces area dependence was used to describe the overall reaction rate. This discussion will also highlight how this simple modeling technique was used to help determine raw material particle size requirements, solidify expected reaction times, and successfully transfer into the kilo lab and pilot plant processes. In addition, comparison of model to lab, kilo and pilot scale will be presented.