Micromixing and memory in chemical reactors

We analyze the mathematical description of the behavior of maximum mixedness and maximum segregation reactors in appropriately defined equivalence classes, all members of any such class behaving equivalently in a well-defined sense in both steady and unsteady state. Three important conclusions are reached. First, we establish under which conditions the behavior of at least one member of an equivalence class is, at all times, in the domain of the initial conditions, and the reactor has therefore perfect memory. Second, when the reactor has perfect memory the boundary conditions play no role whatsoever. so the discussion of what are the appropriate ones for a maximum mixedness Zwietering reactor is shown to be empty. Third, both the possibility of multiple steady states and of the sustained conduction ora biochemical (or more generally autocatalytic) reaction are shown to be related to the memory of the reactor, and not to backmixing.