In this paper, we analyze the dynamics of integrated process networks featuring large recycle streams and small purge streams. We consider a prototype network comprising of a reactor and a condenser, and, within the framework of singular perturbations, we establish that the dynamics of such a network exhibits three time scales. We describe a model reduction procedure which leads to an explicit nonlinear description of the dynamics in each time scale, and we outline a controller synthesis procedure that rigorously accounts for this time-scale multiplicity.