Scale‐Up and Scale‐Down

To gain a qualitative or semiquantitative insight into the major effects of scale-up, a design philosophy based on scale-down of the large-scale operation to a smaller scale has been developed. One starts by defining the desirable large-scale process conditions to give a product that has certain characteristics, such as quality, yield, ease of downstream processing, and so on. Then one constructs a smaller scale version in which these characteristic properties can be examined as a function of the process conditions. This chapter describes how the proper large-scale performance can be achieved through well-designed scale-down experiments, using regime analysis, compartment models, and other engineering models by which desired qualities of the product in large scale can be studied. It discusses a four-step approach of the scale-up work and elaborates on each of the four steps. The chapter also describes how the large-scale process can be improved based on good down-scale studies.