Reactor unsteady state perfect mixing

Identifying the Parameters of an Unsteady State Perfectly Mixed Reactor... 

Consider answer (C). Batch reactors are normally operated in the unsteady-state, perfectly mixed mode. 

The process is described by the mathematical model of a nonisothermal, unsteady state, continuous and perfectly mixed reactor. It is defined by the beloiv differential equations ... 

These are systems where the state variables describing the system are lumped in space (invariant in all space dimensions). The simplest chemical reaction engineering example is thp perfectly mixed continuous stirred tank reactor. These systems are described at steady state by algebraic equations while in the unsteady state they are described by initial value ordinary differential equations where time is the independent variable. 

Shallow bed model. Fan and coworkers (87,88) have treated the case of shallow reactors (bed height low relative to diameter or length for rectangular vessels). While mixing is rapid in the vertical direction, it tends to be limited in the lateral direction so that the residence time distribution for solids can differ considerably from the perfect mixing assumption adopted in most of the models covered in Sections 7.1 and 7.2. Lateral mixing of both solids and gas is described in terms of lateral dispersion coefficients. Unsteady state terms are retained in order to provide dynamic solutions. In other respects the models are "conventional in their treatment of two phases (bubbles and dense phase). It is shown that lateral... 

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